Nautical, Seafaring, & Sailing Terms & Phrases, Terminology & Nomenclature for Sailing, Sailboating, and Sailboarding. A Sailing Glossary with Nautical Definitions for Sailors and Windsurfers of Sailboards, Sailboats, Windsurfing, and Ships; with labeled Illustrations, Photographs, Diagrams, Tables, and Charts.

A windsurfer tilts his rig and carves his sailboard to perform a planing laydown jibe or gybe (downwind turn). See sailboarding terms and nomenclature below.
Sloops (actually knockabouts) racing - the sailboat on the right has a Fractional Rig and the larger vessel (sailboat) has a Masthead Rig. See sailboating terms and nomenclature below.

Nautical & Sailing Terms & Nomenclature


In Honor of Doyle and Virginia McClain
of the sailing vessels Eric and Reverie
Who guided their ships through the Caribbean
And their son through Life

One of the most exhaustive and easily understood glossaries of sailboarding (windsurfing) and sailboating terms & nomenclature anywhere on the web.

Italian Full Rigged tall ship Amerigo Vespucci sailing through New York Harbor showing off all its square rigged sails, staysails, and studding sails. See nautical terminology below.




Nautical, Seafaring & Sailing & Sailboating Terms & Nomenclature
Sailboard, Sailboat & Ship (Man of War) Illustrations and Diagrams


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A beautiful, full color illustration of a sailboard (Windsurfer) and rig, with its nomenclature, terms and parts labeled. 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See sailing terms and terminology below. 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Nautical, Sailing, Sailboating, Sailboarding (Windsurfing) and Seafaring Terms, Phrases, Definitions, Diagrams, and Illustrations
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Aback - the condition of a ship's sails when the wind bears against their front surfaces. They are laid aback, when this is purposely effected to deaden her way by rounding in the weather-braces; and taken aback, when brought to by an unexpected change of wind, or by inattention in the helmsman.--All aback forward, the notice given from the forecastle, when the head-sails are pressed aback by a sudden change in the wind.

Abaft - a relative position toward the stern of a vessel from another object; as, "abaft the forward hatch".

Abeam - at right angles to, or beside the boat

Able Bodied Seaman - a member of the deck crew who is able to perform all the duties of an experienced seamen; certified by examination; must have three years sea service, and be an example to the "ordinary seamen" and "landsmen." Also called Able Seamen and A.B.

Aboard - on or in the boat

About Ship! - the command given to order the crew to tack a vessel

Above Board - on or above the deck, in plain view, not hiding anything

Above Deck - on deck, not over it - that would be "Aloft"

Above-water Hull - the part of the hull that is out of the water; between the waterline and the deck

Absolute Bearing - the bearing of an object in relation to North; either True North or Magnetic North. See also: Relative Bearing, Magnetic Bearing, True Bearing, and Bearing

Abreast -side by side, even with, or by the side. This can refer to two or more vessels or other objects

Abyss - that volume of ocean that is profoundly deep or lying below about 300 fathoms from surface.

Acockbill or A-Cock-Bill 1. Hanging at the cathead, ready to let go, as an anchor.   2. Said of a square-rigger's yard; topped up; having one yardarm higher than the other.

Acoustic Navigation - the use of a sonic depth finder to gauge water depth and bottom features for information to determine a ship's location.

Admeasure - a formal measurement of a vessel for the purpose of documentation

Admiral - an officer of the highest rank and command in the fleet, and who is distinguished by a flag displayed at his main-top-mast-head

Admiral of the Fleet - the officer who superintends the naval forces of a nation, and who is authorized to determine in all maritime decisions

Admiralty Law - the law of the seas, a term for maritime law derived from the British Admiralty department that governs naval affairs

Admiralty Pattern Anchor or Admiralty Anchor - an older (1840's), but very good anchor design that features long arms with a long iron stock set perpendicular to the arms and at the top end of the shank. No longer used for large ships but continues in use for small boats and for moorings. Although it has great holding power in a penetrable bottom it is extremely awkward and the long stock is vulnerable to mechanical damage. When in position the upstanding arm may foul a chain or pierce the hull of a vessel. Also called Fisherman's Anchor. See the illustration at Anchor

Adrift - not moored or anchored, driven without control by the wind, currents, and seas

Afloat - floating on the surface of the water; not aground

Afore - 1. Near the bow   2. further forward. Opposite of abaft

An illustration showing the general directions onboard a ship. Click On Image To Enlarge in New Window

Aft or After - toward the stern or behind it. See illustration at right.

After Bow Spring Line - a mooring line fixed to the bow of the boat and leading aft where it is attached to the dock. This prevents the boat from moving forward in its berth. Its opposite, the forward quarter spring line, is used to keep the boat from moving aft in its berth

Afterdeck - all parts of the upper deck of a ship that lies abaft amidships

After Leading - a line that goes from its point of attachment toward the stern

After-Sails - all sail which are extended on the mizen-mast, and on the stays between the mizen and main-mast. They are opposed to the head-sails, which include all spread on the fore-mast and bowsprit

Against the Sun - Anti-clockwise circular motion. Left-hand lay ropes are coiled against the sun

Agonic Line - an imaginary line on the earth's surface where there is no magnetic declination in relation to True North and South. The agonic line is a line of longitude on which a compass will show true north, since where magnetic declination is zero, magnetic north coincides with geographic north.

Age of Sail - the period in which international trade and naval warfare were dominated by sailing ships.

Agger - two consecutive high and low tides that show little range

Aground - when the hull or keel is touching, resting or lodged on the bottom of the body of water you have been sailing on

Ahead - forward, in front of the vessel

Ahead Reach - the distance traveled by a ship underway at full speed with engines reversed until she comes to a full stop

Ahoy - a seaman's call to attract attention; like "Hello"

Aid to Navigation - a marker or device external to your craft, designed to assist in determination of position of the craft, or of a safe course, or to warn of dangers. View a downloadable and printable US Coast Guard brochure about aids to navigation.

Airs - a measurement of wind speed. Here is a table showing Airs and their relation to jib usage on a knockabout or sloop.

STANDARD JIB SELECTION FOR VARIOUS WIND CONDITIONS ON A KNOCKABOUT OR SLOOP
Light Airs 0 -10 Knots 110% - 150% Genoa (Optional)
Moderate Airs 10 - 20 Knots 90% - 110% Working Jib
Heavy Airs 20 Knots or more 60%- 90% Storm Jib

AIS - Automatic Identification System

Aka - the beams connecting the main hull and the smaller amas on a trimaran, or the windward ama on a Proa or similar vessel

Aldis Lamp - See Signal Lamp

Alee - downwind; opposite of "Windward"

Algae - aquatic plants which thrive near the surface and frequently attach to rocks, pilings, and the bottoms of boats

Alidade - a telescope or other device mounted over a compass, compass repeater or compass rose, for measuring direction; a telescopic azimuth circle

All Hands - entire ship's company, both officers and enlisted personnel, on duty or not

All Night In - having no night watches

Aloft - above the deck; not on deck

Along-Side - side by side, or joined to a vessel, wharf, etc. and lying parallel to the vessel

Altair - a first magnitude (very bright) star, often used in celestial navigation

Altitude - the angle between the horizon and a celestial body. In practice, the celestial navigator will consult tables to estimate the azimuth and altitude of each star line he will attempt, and preset the sextant as an aid to identification of the star or planet. Then he will measure the exact altitude of the body and use that figure to calculate a line on the chart.

Ama - the outrigger(s) on a trimaran, Proa, or similar sailing vessel

American Bureau of Shipping (ABS) - a U.S.- based private classification, or standards setting organization for merchant ships and other marine systems.

America's Cup - The America's Cup race, dating from 1851, is the oldest trophy in sailing and is considered yacht racing's Holy Grail. The race was originally called the Hundred Guineas Cup, presented by the British Royal Yacht Club, and raced around the Isle of Wight. The winning vessel that year was the "America", and the name of the race was changed to "America's Cup". Because of the enormous costs involved, the race is only held approximately every three years.

Amidships - the middle of the boat; either along the longitudinal centerline, or halfway from bow to stern, but not necessarily both.   See General Shipboard Directions illustration.

Amplitude - a measurement of the arc between true East or West and the plane of a selected star or planet at a precise moment in time

Analog - a readout of an instrument which is displayed with a dial and pointer rather than numerically

Anchor - an object designed to grip the bed (lake bed, seabed, riverbed) or ground, under a body of water, to hold the boat in a selected area

Formerly the largest and strongest anchor was the sheet anchor (hence, best hope anchor or last refuge anchor), called also waist anchor. Now the bower and the sheet anchor are usually alike. Then came the best bower and the small bower (so called from being carried on the bow of the vessel). The stream anchor is about one fourth the weight of the bower anchor. Kedges or kedge anchors are light anchors used in warping and kedging.
    Parts of an anchor: (All anchors don't have all parts.)
All Anchors Don't Have All Parts
Anchor Nomenclature
Old Fisherman's or Admiralty Pattern Anchor
An old Fisherman's type ship's anchor with labeled parts and nomenclature
Stockless Navy-Type Anchor
A stockless Navy type ship's anchor with labeled nomenclature
Danforth-Style Anchor
A Danforth-type boat anchor with the anchor's parts labeled
  • Ring (Shackle) - Device used to attach the anchor chain to the shank of the anchor. The ring is secured to the top of the shank with a riveted pin.
  • Shank - The long center part of the anchor running between the ring and the crown.
  • Crown - The lower section of the anchor to which the shank is secured. The shank is fitted to the crown with (on some anchors) a pivot or ball-and-socket joint that allows a movement from 30o to 45o either way.
  • Stock - a crossmember, spar, or rod, that rolls the anchor into an attitude that enables the flukes to dig into the sea bed. Most newer anchors are stockless.
  • Arms - The parts that extend from each side of the crown.
  • Throat - The inner part of an arm where it joins the shank.
  • Fluke or Palm - The broad shield part of the anchor that extends upward from the arms.
  • Blade - That part of the arm extending outward below the fluke.
  • Bill or Pea - Tip of the palm or fluke.
  • Cup - on a Mushroom Anchor, the round ground-holding portion corresponding to the fluke of other designs

Anchor's Acockbill - when the anchor is suspended perpendicularly from the cathead, ready to be let go.

Anchor's Apeak - when the anchor cable is drawn in so tight as to bring the ship directly over it.

Anchor's Atrip - when the anchor is lifted out of the ground. Same as "Anchor's Aweigh".

Anchor's Awash - when the anchor is hove up to the surface of the water.

Anchor's Aweigh - said of an anchor, during the weighing (raising) of the anchor, when just clear of the bottom

Anchor Ball - a round black shape hoisted in the forepart of a vessel to show that it is at anchor

Anchor Bell - a warning bell mounted on the foredeck and rung while at anchor in foggy conditions

Anchor Bend - a very secure knot used to tie rode to anchor

Anchor Buoy - a small buoy secured by a light line to an anchor to indicate position of the anchor on bottom. The anchor buoy is said to be watching if it is floating on the surface. An anchor buoy can be a valuable asset in relocating an anchor that has been lost while weighing anchor or if the anchor has been slipped in an emergency.

Anchor Chain - chain attached to the anchor. The chain acts partially as a weight to keep the anchor lying next to the ground so that it can hold better.

Anchor Chocks - deck fittings for storing the anchor

Anchor Detail - a group of men who handle ground tackle when the ship is anchoring or getting underway

Anchor Ice - ice of any kind that is aground in the sea

Anchor Light - a white light displayed by a boat or ship at anchor. Two such lights are displayed by a ship over 150 feet (46 m) in length, Also called a riding light.

Anchor Pocket - a recess in the bow for storing an anchor; also called a billboard

Anchor Warp - a line used to attach an anchor to a vessel

Anchor Watch - making sure the anchor is holding and that the boat is not drifting. Important during rough weather and at night. Most marine GPS units have an Anchor Watch alarm capability.

Anemometer - an instrument for measuring the speed of the wind

Aneroid Barometer - an instrument that determines atmospheric pressure by the effect of such pressure on a thin-metal cylinder from which the air has been partly exhausted

Angle of Attack - the angle between the chord of a sail and the relative wind or between the chord of a hydrofoil such as a keel or rudder and a vector line representing the true path through the water, taking the amount of sideslip or leeway into account. The term applies to a sail only when the relative wind is forward of the beam.

Angle of Sail - the angle between the vessel's compass course and the true wind

Antarctic Convergence - an irregular line of demarcation in the southern ocean, mostly between 45° and 60° south, along which northward moving Antarctic waters meet sub-Antarctic waters and sink below them with little or no mixing. An abrupt change in sea temperature takes place, and with it a change in sea and bird life. Because of the amount of land mass near the pole in the northern hemisphere, there is no corresponding convergence there.

Antarctica - the earth's fifth largest continent; located at the South Pole. Antarctica is nearly twice the size of Australia, and about 98% of Antarctica is covered by ice that averages at least 1 mile (1.6 km) in thickness. Antarctica, on average, is the coldest, driest, and windiest continent, and has the highest average elevation of all the continents. Antarctica is considered a desert, with annual precipitation of only 200 mm (8 inches) along the coast and far less inland, yet it has huge amounts of ice due to the millions of years of accumulation. Many nations, including Australia, South Africa, the United States of America, Argentina, the United Kingdom, and the U.S.S.R. have claims on the continent and all (48) have entered into a treaty declaring that the continent is an international preserve for scientific research.

Anti-Cyclone - a fair weather, slow moving, weather system based on high barometric pressure

Anti-Fouling - a type of paint or other coating for the under-water hulls of vessels that is resistant to barnacles, moss, seaweed, Teredo worms, marine grass and various other plant and animal life that would want to adhere to a vessel's hull and slow or damage the hull. There are four basic types: ablative, sloughing, modified epoxy, and vinyl. Most usually contain copper biocide or some other repellant. Copper itself is under increasing pressure and is already banned in some areas because it can harm other marine life, too. The technology of the poisons used has progressed from organoarsenicals and organomercurials in the 1960's to relatively harmless organic materials today which target fouling organisms without harming other marine creatures. Recent developments include "foul release" technologies in which non-stick coatings based on silicones or fluoropolymers are able to shed fouling at speeds above about 10 knots.

Antitrades - the prevailing westerly winds of the middle latitudes. The winds to the north of the trade winds which blow in the opposite direction. Since the early square rigged ships could not sail to weather, they had to cross to the New World on the trades or tradewinds, and return by a more Northerly route in the antitrades.   See illustration at Prevailing Winds of the World

Anti-trip Chine - a flared out aft section of the side and bottom of a boat. The purpose is to prevent the hard chine of the boat catching a wake or small wave on a sharp turn.

Apeak or Apeek - 1. more or less vertical. (You may hold your oars apeak, raise your gaff apeak or be apeak your anchor.   2. (of a dropped anchor) as nearly vertical as possible without being free of the bottom.   3. (of an anchored vessel) having the anchor cable as nearly vertical as possible without freeing the anchor. Sometimes it is necessary to do this in order to let wave action break the anchor loose.

Aport - on or toward the port side of a ship; as in: "Come ten degrees aport."

Apparent Horizon - the plane where the earth or water and sky seem to meet

Apparent Time - the time of day indicated by the hour angle of the sun; i.e. apparent noon locally would be the moment when the sun is at its zenith. A properly mounted sundial indicates apparent time. The concept is employed when making navigation calculations. A sun sight at noon and a simple calculation can produce a very accurate line of longitude.

Apparent Wind - the direction and velocity of the wind relative to the speed and direction of the boat which is derived from the True Wind and Wind of Motion. This is the wind you feel on your face when on a moving sailboat.

Apron - a timber fitted abaft the stem to re-enforce the stem and give a sufficient surface on which to land the forward ends of the planks

Arc of Visibility - the portion of the horizon over which a lighted aid to navigation is visible from seaward

Arctic Ocean - the northern polar ocean north of Alaska, Canada, Russia, Greenland, etc.

Argos - a satellite-based system which collects, processes and disseminates environmental data from fixed and mobile transmitters and receivers worldwide. Argos is unique in its ability to geographically locate the source of the data anywhere on the Earth utilizing the Doppler effect.
      Argos was established in 1978 and since that time, it has provided data to environmental research and protection communities that, in many cases, was otherwise unobtainable. The system is fully proven and highly reliable. Many remote automatic weather stations report via Argos. Argos is a key component of many global research programs including: TOGA, TOPP, WOCE, Argo, and others. Since the late 1980's Argos transmitters have routinely been deployed on a large number of marine mammals and sea turtles and continues to serve as the most important tool for tracking long distance movements of both coastal and oceanic species. By uploading of data from pressure transducers attached to wild animals of the oceans, it has been possible to obtain a wealth of knowledge about their diving and foraging behavior.
     Argos was developed under a Memorandum of Understanding (MOU) between the Centre National d'Etudes Spatiales (CNES, the French space agency), the National Aeronautics and Space Administration (NASA, USA) and the National Oceanic and Atmospheric Administration (NOAA, USA).
      The system utilizes both ground and satellite-based resources to accomplish its mission. These include: instruments carried aboard the NOAA polar orbiting environmental satellites (POES) and the EUMETSAT MetOp satellites, receiving stations around the world, and major processing facilities in France and the United States. This fully integrated system works to conveniently locate and deliver data from the most remote platforms to the user's desktop, often in near real-time.

Argosy - an extremely large ship or fleet of ships, especially merchant ships. (archaic)

Arm - 1. a branching waterway from a harbor or bay   2. The crosspiece of an anchor from the crown to flukes

Armada - a fleet of warships

Arming - tallow or other sticky substance placed in the recess at the lower end of a sounding lead for obtaining a sample of the bottom

Ash Can - World War II slang for a depth charge

Ashore - On shore or beach; as in, "Send someone ashore to find fresh water."

Aspect Ratio - the relationship between the height of a sail and its breadth. i.e. A sail with a height of 30' and a breadth of 20' has an aspect ratio of 3:2. A tall and narrow sail is said to have a high aspect ratio.

Astarboard - in or toward the direction of the right side of the ship when facing forward, as in: "Pass the marker, then turn hard astarboard."

Astern - behind the vessel

Astrolabe - a primitive portable insturment used to measure celestial angles. A predecessor to the sextant.

Astronavigation - Celestial navigation. Determining your positon by sightings of celestial bodies.

Astronomical Almanac - a catalogue of tables showing the location of various celestial bodies at specific moments in time throughout the year; consulted by the navigator in preparation for taking sights of celestial bodies. Such tables were known as "The Ephemeris" since the 18th century until 1981 when it was jointly published by the US and Britian. Also called the Nautical Almanac.

Astronomical Twilight - See Twilight

Athwart or Athwartships - at right angles to the fore-and-aft or centerline of a ship.   See General Shipboard Directions illustration.

Atmospherics - interference in reception of radio communications caused by natural phenomena such as lightning or sunspots; as in: "Atmospherics are so bad I can't understand his transmission."

Atoll - a roughly circular island created by and of coral, most common in the South Pacific, surrounding a lagoon

Aurora - a luminous phenomena caused by electrical discharge in the upper atmosphere

Aurora Australis - an aurora in the southern hemisphere

Aurora Borealis - an aurora in the northern hemisphere

Automatic Identification System or AIS - an automated tracking system for identifying and locating vessels by electronically exchanging data with other nearby ships and AIS Base stations. AIS information supplements marine radar, which continues to be the primary method of collision avoidance for water transport. Information provided by AIS equipment, such as unique identification, position, course, speed, bearing and distance of nearby vessels in a radar-like display format. AIS integrates a standardized VHF transceiver with a positioning system such as a LORAN-C or GPS receiver, with other electronic navigation sensors, such as a gyrocompass or rate of turn indicator

Auto Pilot - an electrical automated steering mechanism used to steer a preset course based on the apparent wind. These are expensive and very susceptible to breakdown, but most handy when there is not enough wind to operate a windvane.   Compare to Windvane on this page

Auxiliary - 1. an engine used when there is no wind or for assistance in approaching a dock, etc.   2. a tender carried on deck

Avast! - given as a command to stop, cease, and desist the action currently being carried out (archaic term used in movies)

Awash - setting so low in the water that the water is constantly washing across the top surface

Aweigh - the position of the anchor just as it clears the bottom when raising it

Awl - a pointed wooden or steel tool used to poke holes in leather and for unlaying the ply of a rope for splicing   Compare to Marlinespike and Fid

Azimuth - the horizontal direction of a celestial point from a terrestrial point

Azimuth Circle - a circular sighting device that fits around the ship's compass for taking bearings of terrestrial or celestial bodies


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Back - 1. to alter the position of (a sail) so that the wind will strike the forward face   2. an alteration in the direction of the wind toward the bow of a vessel that makes the wind strike the forward face of the sails   3. to brace (yards) in backing a sail   4. a counterclockwise alteration in the direction of the wind. Opposite of "Veer"   5. to reinforce the holding power of (an anchor) by means of a smaller anchor attached to the main anchor and dropped farther away (to back the anchor)   6. the front surface of a propeller (as opposed to the "face")

Backbone - heavy timbers that form the main fore-and-aft structure of a wooden ship, to which the keel and all the frames are fastened, comprised of its stem, keel, and stern members

Backing Block - a sturdy piece of wood secured inboard behind a planking joint to provide extra strength

Back Splice - an end section of rope that has been unlayed, reversed, and woven back into itself in order to keep it from unraveling and add weight to the end.   See Knot

Backstaff - a navigation instrument used to measure the apparent height of a landmark whose actual height is known, such as the top of a lighthouse. From this information, the ship's distance from that landmark can be calculated. A Davis quadrant. Also has some similarities to the sextant, but cannot be used to take accurate observations of the nightime stars.

Backstay - a wire that runs from the top of the mast to the stern to support the mast and control mast tension, rake, and bend

Backstay - a wire or line that runs from the top of the mast to the stern to support the mast and control mast tension, rake, and bend. Compare to Forestay, Jibstay, and Headstay

Backstay Bridle - a line, near the bottom of the stay that holds the mast stationary from aft, that splits the stay in two and runs to near the corners of the transom in order to allow clearance for movement of the tiller, if so equiped.

Back-winded - to have the wind change to the what has been the leeward side of the sail. If you're on a sailboard, you won't be for long.

Bad Tack - the direction of sail that pushes the lee side of the sail against the mast or sprit, thus deforming the sail and reducing its airflow significantly on lateen, lug, sprit sails, and others that have a yard that crosses forward beside the mast. On some lug rigged sails, the yard can be switched to the other side, but other rigs cannot.

Baggywrinkle - a soft, smooth, plastic covering for cables that prevents sails from chafing as they slide against the cables

Bail - 1. to remove water from the boat   2. a semi-circular metal fitting on the under side of the boom to which the sheet block is attached. The boom bail reduces twist on the boom by allowing the sheet block to change angles as the boom moves from side to centerline to the opposite side of the vessel.

Balanced Helm - a combination of sails and rudder and mast positioning that leaves the helm with no tendancy to turn either to weather or lee. Compare to Lee Helm and Weather Helm

Balanced Rudder - a rudder that has a small portion of the blade forward of the axis, so that it will turn with less effort

Baldheaded Schooner - a schooner without topsails

Ballantine - to flake the foresail halyards in a large coil, then three overlapping smaller coils within, then repeating. The system is used by schoonermen to keep the halyards ready to run free in the event the sail must be doused quickly.

Ballast - stone, iron, gravel, lead, or such like materials, deposited in a ship's hold, when she has either no cargo, or too little to bring her sufficiently low in the water. It is used to counter-balance the effort of the wind upon the masts, and give the ship a proper stability, that she may be enabled to carry sail without danger of capsizing. Inside ballast is within the hull or keel, either cast into it or stowed. Outside ballast is attached to the outside of the hull or keel.

Ballast Keel - a heavy keel, usually cast of lead or iron, that lowers the hulls center of gravity and thus increases resistance to heeling. Lead is more desireable because it is denser and thus takes up less space for its weight and won't corrode; but it makes a vessel more expensive.

Bank - a large area of elevated sea floor that may pose a problem floating across it

Bar - 1. a large mass of sand or earth, formed by the surge of the sea and deposition of silt from a river. They are mostly found at the entrances of great rivers or havens, and often render navigation extremely dangerous and may only be crossed at high tide, but have calmer waters on the shore side.   2. spars to be inserted into the holes in a capstan in order for men to rotate the capstan as they walk around it

Barberhauler - a line or line and block system used to hold the jib sheet inboard or outboard, thus changing its angle

Bare Boat - a boat that is chartered without a crew

Bare Poles - the condition of a sailing vessel when she has no sail set

Bare Steerage Speed or Bare Steerage Way - the lowest speed at which a vessel's rudder is effective, still allowing the vessel to maneuver controllably and safely   Compare to Wakeless Speed and Dead Slow

Barge - 1. a long vessel with a flat bottom used to carry freight on rivers. Barges are usually not self-propelled, but are pushed or towed by a tugboat instead.   2. a long, narrow, light boat, employed to carry the principal sea officers, such as admirals and captains of ships of war, to shore

Bark - See at Types of Sailboats on this page

Barkentine - See at Types of Sailboats on this page

Barnacle - a species of shell fish that looks like a tiny volcano and feeds by gathering nutrients on its feathery appendages called cirri, and is often found attached to the bottom of vessels, pilings, rocks, etc.

Barn Door Rudder - slang for a very large rudder

Barograph - an instrument that continuously records atmospheric (barometric) pressure allowing the user to visualize changes in the pressure

Barometer - an instrument for measuring atmospheric pressure

Bar pilot - a bar pilot guides ships over the dangerous sandbars at the mouth of specific rivers and bays

Barrelman - a sailor stationed in the crow's nest

Barrier Reef - a coral reef lying offshore and running parallel to the shoreline which may block access to navigation

Baseline - a horizontal fore-and-aft line drawn below the keel in lines plans and loftings from which heights to various points on the hull are measured

Basin - 1. a docking facility located along a tidal river or in a harbour; as in: "yacht basin".   2. a small depression in the ocean floor.   3. a large depression in the earth's surface filled with seawater; as in: "Atlantic basin".

Bathyscaphe - a relatively small, maneuverable, submersible vessel specially constructed to withstand enormous pressure and used to explore the deep ocean floor. The Alvin and the Trieste are two famous examples of the bathyscaphe.

Bathysphere - a hollow sphere heavily built of steel alloy and designed to withstand enormous outside pressure, used to carry observers to the deep ocean floors. The bathysphere, which was lowered on a cable and could not maneuver, has been largely replaced by the bathyscaphe for deep ocean exploration

Batten - 1. thin, stiff strips of plastic, fiberglass or wood, placed in pockets in the roach & leech of a sail, to assist in keeping the sail's proper airfoil form. On a sailboard sail, battens are usually tapered with the fore end thinnest and may extend the full width of the sail. 2. to cover (a hatch) so as to make watertight (usually followed by "down"). 3. a thin strip of wood used to fair the lines of a boat throughout the construction process. 4. certain long, thin timbers used in hull construction, as in batten seam planking

Batten Down - to secure the hatches and all things on deck and within the hull

Batten Pocket - pockets in the roach and trailing edge of the leech of a sail to slide battens into, to stiffen the sail, and in some cases, running from the roach to the luff. See Batten

Batten Seam - a method of construction used for double planking wooden boats in which the lighter weight inboard planks are placed parallel to the outboard planks, but offset so that the seams and joints are covered. The method creates considerable longitudinal strength, and reduces the likelihood of leaking, at the expense of greater weight.

Bay - 1. a gulf or inlet of the sea-coast, between two promontories, or capes of land, where ships frequently ride at anchor, sheltered from the wind and sea   2. a large open area belowdecks on a ship, as in cargo bay, sick bay

Beach - 1. the part of the shore of an ocean, sea, large river, lake, etc., washed by the tide or waves.   2. to haul onto or run a vessel onto a beach

Beach Boat - a style of small boat that can be launched from shore by a few strong men. Often double enders, such boats are common where the tidal range is great

Beach Start - a technique for getting underway by stepping directly on a sailboard, boom in hand, in knee-deep water without uphauling.

Beacon - Beacons are aids to navigation that are permanent structures attached to the bottom of a body of water, not floating or may be structures on shore. A beacon that has a light attached is simply referred to as a “light”; a beacon without a light attached is called a “daybeacon.” View a downloadable and printable US Coast Guard brochure about buoys and other aids to navigation.

Beak or Beakhead - a protruding part of the foremost section of a sailing ship. It was fitted on sailing vessels of various time periods for different reasons. Early on, a beak or beakhead was often used as a ram in order to punch holes in an enemy ship at or near the waterline. From the 16th to the 18th century they served as a working platform by sailors working the sails of the bowsprit, the forward-pointing mast that carries the spritsails. The beakhead would be one of the most ornate sections of a ship, particularly in the extravagant Baroque-style ships of the 17th century. The sides were often decorated with carved statues and located directly underneath was the figurehead, usually in the form of animals, shields or mythological creatures. The beakhead also housed the crew's toilets (head), which would drop refuse straight into the sea without sullying the ship's hull unnecessarily.

Beam - 1. the width of a boat at its widest   2. transverse supports running from side to side to support the decks and hold the gunwales at their proper distance from each other   3. a direction; at, near, or off a side of the vessel.   See General Shipboard Directions illustration.

Beam Ends - the sides of a ship. "On her beam ends" may mean the vessel is literally on her side with her beams almost vertical and possibly about to capsize; more often, the phrase means the vessel is listing 45 degrees or more. A vessel may be laid on her beam ends ashore for cleaning when a cradle is not available

Beam Reach - a point of sail where the craft is sailing at a right angle to the wind. Maximize window at Points of Sail Illustration to see more detail. (Opens in new window)

Beam Seas - ocean waves that approach the vessel from the side, a very dangerous situation in heavy weather

Beamy - this describes a vessel that has a proportionally wide measurement from side to side; it may be slow, but stable

Bear a Hand - an order to quickly join in and help with the work

Bearing - the position of one object relative to True North, Magnetic North, or to another object. See also: Absolute Bearing, Magnetic Bearing, True Bearing, and Relative Bearing

Bear Down On - to approach from windward

Bear Off or Bearing Away - to turn the bow of the vessel further away from the Eye of the Wind. Also called "Falling Off." Opposite of "Heading Up"

Bear Up - to change the heading of a vessel toward the wind

Beat - 1. to sail upwind in a sailboat by sailing alternate legs with the wind first on one side of the bow, then on the other.   2. to sail close hauled.

Beating - sailing close hauled through a series of tacks in order to get straight upwind of your original position. For more information, see Beating at Wikipedia.org

Beating Straps - footstraps that are parallel to the centerline of a sailboard and located nearest to the centerboard trunk or case.

Beaufort Scale - a numerical scale for indicating wind speed, named after Admiral Sir Francis Beaufort, who devised it in 1806. The initial scale of thirteen classes (zero to twelve) did not reference wind speed numbers, but related qualitative wind conditions to effects on the sails of a man of war, then the main ship of the Royal Navy, from "just sufficient to give steerage" to "that which no canvas sails could withstand." At zero, all his sails would be up; at six, half of his sails would have been taken down; and at twelve, all sails would be stowed away.   See more at Wikipedia

Becalmed - without wind and unable to make headway

Beck - the reach of a coastal river that dries at low tide

Becket - 1. a short length of rope for securing spars, coils of rope, etc., having an eye at one end and a thick knot or a toggle at the other, which is passed through the eye.   2. a grommet of rope, as one used as a handle or oarlock.   3. a grommet or eye on a block to which the standing end of a fall can be secured.   4. a wooden cleat or hook secured to the shrouds of a sailing vessel to hold tacks and sheets not in use.

Bedding Compound - a caulking material for mating two surfaces and making them watertight

Beetle - a heavy mallet used for driving caulking into a seam with a caulking iron

Before the Wind - running with the wind

Beginner Board - these sailboards have a daggerboard, are almost as wide as Formula boards, and have plenty of volume, hence stability.

Beginner Jibe (Gybe) - a low speed sailboard jibe in which the sailboard enters and exits the turn at non-planing speed that involves turning the board by moving the sail forward to initiate the turn downwind, moving the feet to near the centerline of the sailboard to avoid tipping the board and falling into the water, flipping the clew of the sail around the mast toward the bow of the board, moving the hands to the other side of the wishbone boom, leaning the mast back to complete the turn, then moving the feet into position on the other side of the board; in that order. See how easy it is!!!   Go To "Jibe"

Belay - 1. to make secure a line, usually to a belaying pin or cleat   2. an order to stop doing or rescind something; as in "Belay my previous order!

Belaying Pin - rods of iron or hard wood that are inserted into a hole in a rail, to which running rigging may be secured, or belayed. Pulling the Belaying Pin immediately releases the line.

Bell - 1. a bell buoy   2. the Ship's Bell

Bell Buoy - a floating navigation aid, anchored in place and having a bell mounted in the framework with a free-swinging clapper which sounds the bell as the buoy rolls in the seas. A bell buoy is usually mounted near a rock or shoal to warn of a serious danger to navigation. In clear daylight, you can see the buoy; at night or in fog, you can hear the bell. In common usage, the bell buoy would be referred to as simply a "bell".

Belly - the deeply rounded portion of a filled sail

Below - any inboard portion of a ship beneath the main deck

Bend - 1. to tie two lines together. 2. a knot used to tie two ropes together. Compare to "Hitch"

Bend On - to attach a sail in preparation for sailing

Bending Jackstay - a rope, iron rod, or piece of wood attached to a spar, and onto which a sail may be bent

Bends - a painful and potentially fatal affliction caused by nitrogen bubbles from the blood collecting in the joints, which can happen when a Scuba or deep sea diver ascends from depth too quickly

Bent - tied or secured by hitches or knots; as in: "The awning is bent to the shrouds."

Bent Frame - a type of wooden frame made to shape by steaming the wood and forcing it into shape

Bergy Bit - a large chunk of an iceberg showing about 5 m above sealevel, and 100 m or more in size

Bermudan Rig - A triangular mainsail, without an upper spar, which is hoisted up the mast by a single halyard attached to the head of the sail. This configuration, introduced to Europe about 1920, allows the use of a tall mast, enabling sails to be set higher where wind speed is greater. Most modern sloops now use this rig instead of a gaff rigged mainsail. Another name for Marconi Rig

Bernoulli Effect - the function of fluid dynamics that tends to draw together two ships that are moving side by side   2. the function that tends to accelerate fluid through a pipe submerged in a moving stream   2. the function of wind accelerating through a restricted opening, such as between overlapping sails. (All of these definitions are wildly oversimplified.) After Daniel Bernoulli, 18th century scientist, known as the father of fluid dynamics.

Berth - 1. a bed on a boat.   2. a space in a port or harbor where a vessel can be tied up beside a wharf, quay, or dock   3. to bring a vessel along side a wharf or place it in a slip

Best Bower - the largest anchor carried by a vessel

Bibbs - a sturdy set of timbers, attached to the mast at the hounds, which support the Trestletrees on a wooden mast. Part of the "Top" where implemented

Bible - jargon for the large porous stone used to scrub the decks of wooden ships. Also called "Holystone" because it brought sailors to their knees

Bight - 1. the central portion of a rope between the ends or end and standing (hitched to an object) part of the rope. A hitch or knot tied "on the bight" is one tied in the middle of the rope, without access to the ends.   2. a curve or arc of a rope no greater than a semicircle. Compare to Loop and Turn   See Bight at Wikipedia.   3. an indentation in the shoreline so wide that it may be sailed out of on one tack in any wind.   4. the bay enclosed in a bight of land.

Bilge - the lowest part of a boat, designed to collect water that enters the boat so that it can be removed

Bilgeboard - a lifting foil used in a sailboat, which resembles a cross between a leeboard and a centerboard. Mounted between the centerline of the boat and the sides, they are almost always asymmetric foils mounted at an angle to maximize lateral lift while minimizing drag and are most often found on racing scows. When sailing, the windward bilgeboard is retracted into the hull of the boat, so that it creates no drag. The leeward foil provides the lift to counter the lateral force of the sail, and converts it into forward motion. The bilgeboards are angled so that as the boat heels, or leans under the force of the wind, the leeward bilgeboard becomes more vertical, and provides the most possible force in the desired direction.
      Bilge keels minimize the draft of the vessel compared to a single fin keel thus enabling it to negotiate shallower water. Bilge keels on sailing yachts extend below the lowest point of the hull extending slightly outwards. Such an arrangement also enables the vessel to stand upright on firm sand or mud at dry moorings without the need for detachable legs, and is simpler than retractable fin keels while giving the hull greater protection. Bilge keels are not as effective as central fin keels in preventing leeway (sideways slippage) caused by crosswinds but are preferred by many small craft owners due to their other advantages.

Bilge Keel - a non-moving stabilizer consisting of a pair (one on each side) of small keels or fins extending out at approximately 45° from a vessel's hull at the turn of the bilge in order to lessen or slow the rolling of the vessel. Bilge keels do not have any components inside the hull that would adversely affect cargo or storage space, but do increase the drag of the vessel slightly.

Bilge Pump - a hydraulic pump installed at the lowest inboard part of the hull to remove accumulated water

Bilge Water - all water leaked into the vessel or otherwise accumulated at the lowest interior part of the hull

Bilged On Her Anchor - a vessel that has run upon her own anchor; a good way to damage your hull

Billboard - a permanent stowage mount for the anchor

Bill of Health - a document provided to a ship's master by port health authorities indicating the state of health of the ship's company and of the port from which the ship is sailing, as well as other ports to which the ship intends to sail. The procedure is a result of international agreements, with the intent to keep infectious diseases from spreading to otherwise healthy areas from the crew of visiting ships.

Bill of Lading - an itemised list of all the cargo on board, issued by a shipping company as a receipt and as a customs document.

Billethead - 1. a bitt mounted at the stem of a whaleboat for securing the harpoon line (pennant).   2. an ornamental, curved stempiece, below the bowsprit and above the cutwater, that usually ends in a scroll or fiddlehead

Bimini or Bimini Top - a weather-resistant fabric stretched over a frame, fastened above the cockpit of a sailboat or flybridge of a power yacht which serves as a rain or sun shade. A similar type of shelter on a boat, but with added forward and side protection, is called a Dodger.

Binding Knot - a knot that may be used to keep an object or multiple loose objects together, using a string or a rope that passes at least once around them. There are various binding knots, divided into two types: Friction knots are held in place by the friction between the windings of line. Knotted-ends knots are held in place by the two ends of the line being knotted together.

Binnacle - the post on which the ship's compass is mounted or the box the compass is kept in

Bireme - an early Roman galley propelled by two banks of oars

Bite - to hold fast to the ground (bottom); said of the anchor

Bitt or Bitts - a strong vertical post or pair of posts fixed on or through the deck aboard ship for making mooring lines and towlines fast   See illustration at Deck Fittings on this page

Bitter End - the end of a line that is secured. A bitt is used for tying lines to. In fact the bitter end is the end of the Anchor "Cable" that connects to the Anchor Bitts in the cable or chain locker under the forecastle or poop using the bitter pin. (British nautical usage). Other uses are borrowed from this derivation.   Also see Knot

Blackstrake - a strip of extra planking fastened outboard on the hull as chafing gear and protection against impact damage. A rubbing strake. On early ships these were usually covered with black tar.

Blade - 1. the broad, flattened portion of an oar   2. the "wings" of a propeller

Blanket - to sail parallel to and just to windward of another ship, thus blocking or stealing her wind

Block - a pulley; the complete assembly of sheaves (grooved wheels), axels, and shell (side plates). It may be fixed to some part of the vessel or spars, or tied to a line.

Block Nomenclature
A Wooden Block
A wooden block illustrating its nomenclature
  • Fiddle Block - two or more sheaves in one block, each having a separate axle, arranged so that the sheaves are in line one below the other
  • Snatch Block - a block having one side that opens so that a line may be introduced from the side and the block locked around it rather than having to be threaded into it
  • Ratchet Block - a block whose sheave turns only in one direction, making it easier to hold a line under tension
  • Handy Billy - a loose block and tackle with a hook or tail on each end, which can be used wherever it is needed. Usually made up of one single and one double block. May also be called a Burton
  • Turning Blocks - horizontally or vertically mounted blocks used to redirect lines on or to the deck (as from the mast to the cockpit).
  • Block & Tackle - See Block & Tackle below

Block and Tackle - an arrangement of two or more pulleys (blocks), and ropes and hooks (tackle), used to reduce the amount of force needed to move heavy loads. One block is attached to the load, and rope or chains connect this block to a fixed block. Each block may have multiple wheels (sheaves) for the rope to pass over numerous times. Pulling on the Fall or Hauling Part of the rope or chain slowly draws the load-bearing block toward the fixed block with high mechanical advantage (MA).

  • A Block & Tackle may be:
    • "Rigged to Advantage" - the pull on the rope is in the same direction as that in which the load is to be moved and where the Fall or Hauling Part is coming from the MOVING or Traveling Block; in other words, pulling UP on the hauling line LIFTS the weight. The Fall or Hauling Part is pulled from the moving block. This gives a greater mechanical advantage than rigging to disadvantage.
      To Disadvantage: As Line is Hauled DOWN, Weight Goes UP
      Blocks and Tackle
      ALL BLOCKS RIGGED TO DISADVANTAGE
      Several blocks and tackle showing various configurations and their names as used on ships. All these configurations illustrate blocks rigged to disadvantage, since the weight lifts as the line is pulled downward; force applied and weight moving in opposite directions.
    • "Rigged to Disadvantage" - the pull on the rope is in the opposite direction to that in which the load is to be moved and where the Hauling Part is coming from the FIXED or Standing Block; in other words, pulling DOWN on the Fall or Hauling Part LIFTS the weight. The Fall or Hauling Part is pulled from the Standing Block. This gives less mechanical advantage than rigging to advantage.
    While rigging to advantage is obviously the most efficient use of equipment and resources, there are several reasons why rigging to disadvantage may be more desirable. The decision of which to use depends on pragmatic considerations for the total ergonomics of working with a particular situation. Lifting from a fixed point overhead is an obvious example of such a situation.
    There are many different configurations by which a simple set of block and tackle can be arranged, but basically, the Total (NOT PER BLOCK) number of sheaves in the system determines the type:
    • One sheave - Whip, if reaved to disadvantage - (MA=1); Runner, if reaved to advantage - (MA=2)
    • Two sheaves - Gun Tackle, if reaved to disadvantage - (MA=2); if reaved to advantage - (MA=3)
    • Three sheaves - Single Luff Tackle or Jigger, if reaved to disadvantage - (MA=3); Luff Tackle, if reaved to advantage - (MA=4)
    • Four sheaves - Twofold Purchase, if reaved to disadvantage - (MA=4); if reaved to advantage - (MA=5)
    • Five sheaves - Gyn Tackle (pronounced "gin"), if reaved to disadvantage - (MA=5); Double Luff Tackle, if reaved to advantage - (MA=6)
    • Six sheaves - Threefold Purchase - if reaved to disadvantage - (MA=6); if reaved to advantage - (MA=7)

    Mechanical Advantage (MA) of a Block and Tackle

    The mechanical advantage of a block and tackle is equal to the number of parts (falls) in the line, that either attach to or run through the MOVING block, counting both upward and downward moving parts of the line. For example, take a block and tackle with two sheaves on both the Traveling block and the Standing Block. If one compares the blocks, one will see one block will have four lines running through its sheaves. The other will have 4 lines running through its sheaves (including the part of the line being pulled or hauled (Fall)), with a 5th line attached to a secure point on the block. If the Fall or Hauling Part is coming out of the Standing block, the block and tackle will have a mechanical advantage of 4. If the tackle is reversed, so that the Fall or Hauling Part is coming from the Traveling Block, the mechanical advantage is now 5.

    The mechanical advantage of a block and tackle is relevant, because it dictates how much easier it is to haul or lift your load. A tackle with a mechanical advantage of 4 (a double tackle) will be able to lift 100 lbs with only 25 lbs of tension on the Fall. In the diagram above right the mechanical advantage of the tackles shown is as follows:

    • The formula used to find the effort required to raise a given weight is:

      S * P = W + (nW)/10

      Where:

      • S is the power in the Fall or Hauling Part.
      • P is the power gained by the purchase (this is the same as the number of parts at the moving block).
      • n is the number of sheaves in the purchase.
      • W is the weight lifted.
      • 10 is the denominator of the fraction for friction. An arbitrary 10%.

        Mechanical advantage correlates directly with linear movement ratio. The linear movement of the line of a tackle refers to the relative linear movement of the hauling line to the hauled load. A line with a mechanical advantage of 4 has a velocity ratio of 4:1. In other words, to raise a load at 1 meter, 4 meters of line must be pulled from the hauling part of the rope.

Blow Out - 1. to tear a sail from carrying too much wind; "I'm afraid we might blow out a sail." 2) To slacken and dissipate, referring to a storm; as in: "After several days the storm will blow itself out."

Blower - an explosion proof fan used to exhaust explosive gasses overboard before activating engines or electrical equipment

Bluejacket - an enlisted man in the navy

Blue Water - deep water offshore, beyond the continental shelf

Blue Water Sailing - open ocean sailing, as opposed to being in a lake or sound

Board - to go onto a vessel

Board Boat - a small boat, usually cat rigged. May have a shallow cockpit well. Typically has almost no freeboard. A Sunfish is a board boat.

Boarding Ladder - a temporary set of steps lowered over a vessels side

Boarding Party - a group of people organized to go on board a vessel to attack or inspect, usually bearing arms.

Boat - 1.a watercraft of small to modest size designed to float or plane on water, and provide transport over or through it. 2.any watercraft that operates only on inland waterways.   3. to bring something inboard a small vessel, as; "Boat your oars as we come along side their boat."

Boat Falls - blocks and tackle with which boats are hoisted aboard at davits

Boat Hook - a pole with a blunt hook designed to aid in docking or mooring operations, picking things up, or fending off

Boatman - 1. a commercial boat operator   2. a man who makes his living on boats

Boat Plug - a plug fitted in the bottom of the stern or at the bottom of the transom to drain the water out of the bilges when the craft is out of the water

Boatswain or Bosun - a non-commissioned officer responsible for the sails, ropes and boats on a ship who issues "piped" commands to seamen

Boatswain's Pipe or Bosun's Call (Pronounced "Bosun") - a pipe that is made of a tube (called the gun), that directs air over a grape-sized metal sphere (called the buoy) with a hole cut in the top (called the hole). The player opens and closes the hand over the hole to change the pitch. Other parts of the boatswain's call are the keel, a flat piece of metal beneath the gun that holds the call together, and the shackle, a keyring that connects a long silver or brass chain that sits around the collar, when in ceremonial uniform.   The historical use of the boatswain's call was a way to pass commands to the crew when the voice could not be heard over the sounds of the sea. Because of its high pitch, it could be heard over the activities of the crew and bad weather.

Boatswain's Chair or Bos'n's Chair (Pronounced "Bosun") - a board seat on which a man working aloft is swung

Boatwright - a builder of small vessels. A shipwright builds ships.

Bobstay - a stay attached to the bottom of the bowsprit and to the bow to hold the bowsprit down and counteract the force of the forestay. Many times there are two. On a vessel with a Dolphin Striker, this is called a Martingale. This needs to be very strong and not stretchable, so it is usually made of wire rope or heavy chain since it counteracts most of the upward and rearward pull of the foremast through the forestay.

Body Plan - in a lines plan of a vessel, the sectional view of the hull as seen from the bow and stern

Bollard - a substantial vertical pillar to which lines may be made fast. Generally on the quayside rather than aboard ship.

Bolster - chafing gear made like a cushion, used where needed to protect rigging from wear

Bolt Rope - a rope sewn into the luff of a sail for use in attaching to the standing rigging

Bonaventure Mizzen Mast - in larger galleons, a fourth mast with, usually, a lateen-rigged mizzen

Bonnet - a strip of canvas laced onto the bottom of a loosefooted jib in order to increase the sail area in fair weather. The bonnet is removed when wind velocity increases again.

Booby Hatch - a small hatch through the deck of a ship with a raised frame and a sliding cover. This hatch is especially useful when the decks are awash, since the high sides keep the water from pouring in, and the small size of the opening limits the amount of water than can splash in

Boom - the horizontal spar to which the foot of a fore & aft sail is attached

Boom Bra - a padded protective cover for the boom head that keeps the boom head from denting a sailboard as the mast pivots forward during a fall.

Boom Brake
A photograph illustrating a modern sailboat's boom brake and line.

Boom Brake - a device designed to control the swing of the boom on a sailboat. The boom brake acts as a preventer when sailing downwind, and can also be used to jibe the mainsail in a slow controlled movement.
Uncontrolled jibes can be violent and often damage elements of the rig, and can knock crew overboard or inflict serious and sometimes fatal injuries to crew in the path of the boom or the mainsheet and associated hardware. The boom break helps avoid this.

Boom Clamp - a lever on the boom head of a wishbone boom that tightens around and attaches the boom to the mast of a sailboard. Early models of sailboard booms didn't have a clamp. They had to be lashed to the boom. The boom clamp is a major improvement that has undergone many modifications and some current models are still much better than others.

Boom Crotch or Crutch - a removable support to set the boom on when it is not in use to keep it from swinging

Boom Head - the fore end piece on a wishbone boom that connects the two sides of the boom

Boom Iron - a set of iron brackets near the outboard ends of a yard through which the studding sail boom is mounted to support studding sails out beyond the yard arm.

Boom Jack - a boom vang

Boomkin - a short horizontal spar extending from the stern of a vessel to which a sheet block is attached for a long, overhanging boom; or for vessels without running backstays, the backstay may be attached

Boom Traveler - an arrangement of a wide metal bracket or horse often mounted athwartships on the cabin top or deck under the boom to which the sheet block is secured allowing it to move to the lee side at each tack.

Boom Vang - a line attached to the bottom of the boom and the mast, a short distance from the mast, that adjusts downward tension on the boom. Also called a Boom Jack

Boot - a wrapping or sheathing around the mast at the partners in order to keep water from going below

Boot Top - 1. a painted line on a vessel's hull that marks the designed load waterline (LWL). A vessel loaded such that its boot top is below water level is in extreme danger of either sinking or, if the overload is on or above decks, capsizing and turtling due to its new high center of gravity. Also, if a hull is given a new coat of paint, it is extremely important that its boot top be repainted at the proper height on the hull.   2. the area between the water lines of a ship when fully loaded and when unloaded. The portion of the hull above the boot top is the "topsides" and the portion below is the "bottom."

Bore - an incoming tide that advances as a sharply defined wave in certain rivers and inlets that have a long way to run over a gradually sloping bottom

Bos'n - See Boatswain

Bosun - See Boatswain

Bottlescrew - See Turnbuckle

Bottom - 1. that part of a vessel that is underwater   2. ground, the terrestrial surface submerged under the ocean, lake, river, etc.

Bottom Paint - specialized paint containing ingredients like copper and lead that are toxic to marine crustaceans and algea, applied to the bottom of boats to inhibit growth of marine life that can substantially reduce the speed and range of the vessel.

Bottom Sample - a portion of the material forming the bottom, brought up for inspection

Bouse - see "Bowse"

Bow - the front of the boat or sailboard   See General Shipboard Directions illustration.

Bow and Quarter Line - a group of ships arranged such that each ship follows on the quarter of the ship ahead. With this type of convoy arrangement, each ship is clear of the wake of the ship ahead making it easier to keep up.

Bower - an anchor carried at the bow of a vessel

Bow Grace - pieces of scrap rigged around the bow at the waterline to protect the hull from ice damage

Bow Line - a painter or line to the bow

Bowline - 1. a simple hitch used to tie a fixed loop at the end of a line, identical in structure to the sheet bend, except it is tied in one line instead of tying two together. It is simple, strong, virtually slip proof, and easy to untie if not under strain. If under strain, it can be VERY difficult to untie. The Bowline is one of the eight most useful knots a sailor needs to know.   2. a rope fastened near the middle of the leech, or perpendicular edge of the square sails, by three or four subordinate parts, called bridles. It is only used when the wind is so unfavourable that the sails must be all braced sideways, or close-hauled to the wind: in this situation the bowlines are employed to keep the weather, or windward, edges of the principal sails tight forward and steady, without which they would be always shivering, and rendered incapable of service.

Bow Thruster - an auxiliary motor and propeller mounted athwartships at the bow, and employed to maneuver the ship sideways

Bowse - 1. to pull or hoist with a block and tackle   2. to secure something by wrapping with small stuff

Bowsprit - a near-horizontal spar extending from the bow of the boat, used as an anchor for the foremost mast by the forestay and offering additional space on which sails can be rigged

Bowsprit Shrouds - opposing cables or chains fitted horizontally from the end of the bowsprit to chainplates on the bow's sides to support the bowsprit from side to side.

Box-Hauling - a method of veering or jibing a square rigged ship, without progressing to leeward appreciably. It is performed by heading bow to windward until most speed is lost, but steerage way is still barely maintained. The bow is then turned back downwind to the side it came from, aftermost sails are brailed up to spill the wind and to keep them from counteracting the turning force of the foresails, and the ship allowed to pivot quickly downwind without advancing. They are, however, extended as soon as the ship, in veering, brings the wind on the opposite quarter, as their effort then contributes to assist her motion or turning. Box-hauling is generally performed when the ship is too near the shore to have room for veering in the usual way. (Falconer- 1779)

Boxing - an operation in sailing somewhat similar to box-hauling, but is a tack rather than wearing about or veering. It is performed by turning head to wind and backing the headsails, then, as sternway is made, reversing the helm to turn the bow down wind on the opposite side. Aftermost sails may be brailed up to keep them from counteracting the turning force of the foresails, and the ship allowed to pivot quickly downwind, then the brails released and the yards braced about again when the wind hits the opposite quarter of the vessel to assist in turning. (Smith - 1629)

Box the Compass - To state all 32 points of the compass, starting at north, proceeding clockwise. Sometimes applied to a wind that is constantly shifting.

Brace - 1. a rope near the end of each yard by which a yard is swung about to alter its angle to the wind.   2. to swing or turn the yards of a ship by means of the braces. Yards are "Braced Aback" to bring the wind onto the forward side of the sail and to take way off the ship. They are "Braced About" to bring the ship onto the opposite tack and "Braced Abox" to bring the headyards flat aback to stop the ship. They are "Braced In" to bring the yards athwartships when running and they are "Braced Sharp" or "Braced Up" to make the yards as close as possible to fore-and-aft when sailing close-hauled.

Brackish - half salt water and half fresh water, as where a river dumps into the seas

Braided Line or Rope - a modern configuration of line that is braided instead of twisted. It may be single or double braided, one braid over another braided core. Easy to handle because it does not tend to tangle as much as twisted line

Brails - 1. small ropes used to haul in or up the leeches, bottoms, and, sometimes, luff and corners of sails, for furling. These brails belong only to the two courses and the mizzen sail of a square rigged sailing vessel. The command is, "Hale up the brails", or, "Brail up the sails."   2. a general name given to all the ropes which are employed to haul up, or collect to their yards, the bottoms, lower corners, and skirts of the other great sails, for the more ready furling them whenever it shall be necessary. The operation of thus drawing them together, is called brailing them up, or hauling them up in the brails.   3. ropes led from the leech on both sides of a fore-and-aft, loose-footed sail and secured to the mast at deck level, to gather the sail close to the mast, spilling wind and thereby slowing the ship. The command is "Brail the sails," or "Brail Up the sails."

     Some spritsails have a vertical batten set in a pocket about two to three feet aft of the luff, a series of brails run horizontally from points on the batten pocket through rings on the luff and splice into a line running down the mast. To shorten sail, the skipper eases the snotter and pulls on this reefing line, bringing the batten forward to the mast and thereby reducing sail area in one easy operation by as much as a third. He then secures the reefing line and the snotter.

Brake - a device on the windlass on larger vessels to control or slow the descent of the anchor

Brass - 1. an alloy of copper and zinc commonly used for fittings, accessories and decorative pieces on a vessel   2. senior officers

Breach - 1. a hole or opening broken in the hull through which water will enter   2. to break an opening in the hull   3. the action of a whale when it leaps clear of the water   4. a leap of a whale clear of the water

Breadth - an admeasurement term for the width or beam of a ship at its widest point across the deck

Break - 1. to dismantle and scrap a ship   2. for the crest of a wave to fall down the face of the wave   3. the joint or step between two deck levels

Breakers - waves cresting and spilling over as they reach shallow water; surf

Break Out - to bring a piece of equipment out of storage and put it to use

Breakwater - a man-made extension of the shoreline made to take the brunt of wave action and erosion and protect the waters on its lee side; a jetty

Breaking Yard - a shipyard where ships are taken apart for scrap

Bream - to clean the bottom of a vessel, of barnacles, seaweed, moss, etc., using torches to soften the pitch, and scrapers

Breast Hook - the joint in the heavy timbers of a wooden vessel that firmly connects the keel and the bow timbers

Breast Line - a docking line going at approximately a right angle from the boat to the dock, usually at the bow and stern

Breech - the opening in a block through which the line is rove   See at Block on this page

Breeches Buoy - a canvas seat shaped like breeches (pants) suspended under a life buoy which is swung from a tight hawser by a snatch block and used for hauling a man from one ship to another, or from a shipwreck to the shore.

Bridge - a structure above the weather deck of some modern ships, extending the full width of the vessel, which houses a command center, itself called by association, the bridge

Bridle - 1. a line attached at both ends in order to distribute the strain between the two points   2. a wire mounted transversely on deck of a small sailboat to which the main sheet block is secured allowing it to slide to the lee side at each tack. A type of traveler.

Brig - See at Types of Sailboats on this page

Brigantine - See at Types of Sailboats on this page

Bright Deck - a wooden planked deck that has been varnished or oiled, rather than painted or coated with canvas

Bright Work - varnished woodwork or polished metal of a vessel

Brine - 1. seawater with a high salt content   2. foam which gathers at the edges of seawater on the beach   3. the sea, poetic usage

Bring To - the act of stopping a vessel by turning her head into the wind

Bristol Fashion - shipshape; clean, neat, orderly, and meeting high standards of seamanship

Broach - to be thrown broadside into the trough and out of effective control while running downwind; caused by the stern outrunning the bow as it slides down the face of a wave.

Broad Plank - one of several planks just above the garboard plank

Broad On... - in the general direction of. For example, "Broad on the starboard beam" describes the general direction that is forward of the beam and on the starboard side of the vessel

Broad Reach - a point of sail where the boat is sailing away from the wind, but not directly downwind. Maximize window at Points of Sail Illustration to see more detail.(Opens in new window)

Broadside - to fire all the cannon on one side of a vessel at the enemy

Brow - the gangplank. A moveable ramp used for boarding/disembarking from and loading/unloading a vessel

Brume - light fog or mist

Brummel Hooks - a type of patented hook, used in pairs to quickly attach two lines or a line to a sail. These hooks are figure 8 shaped with a narrow beveled opening in the side of one of the loops of the eight so that when the openings of two hooks are held at right angles to each other, they will slide together or apart, but once joined and the angle changed, they hold like two links of chain. A very good, quick attachment device, however, caution should be considered in using brummel hooks in places like the clew attachment of a jib, where in tacking, the clew of the sail is thrown violently and erratically as it flaps, which might cause the openings to align properly and disengage.

Buccaneer - a pirate and privateer of the Spanish coast of the Americas and Caribbean Sea

Bulb Keel - a fin keel with a large, heavy aerodynamicly shaped weight at the very bottom to increase the vessel's lateral stability

Bulbous Bow - a large, rounded, forward protrusion below the wateline at the bow of many large displacement hulled, modern vessels. The bulb modifies the way water flows around the hull, reducing drag and increasing speed, range, stability, and fuel efficiency.

Bulkhead - An upright wall within the hull of a ship. Particularly a load bearing wall.

Bulwark - The extension of the ship's topsides above the level of the weather deck.

Bulldog Grip - a U-shaped steel clamp with threaded ends and a bridge tightened down with nuts, used to hold two cables together

Bullnose - a chock placed at the stem (bow) that is used to pass the anchor chain through while a vessel is being towed or while moored to a buoy, or for use to pass the bow line while moored to a pier

Bullseye - A single Deadeye, used to guide and control a line and, particularly in older vessels, to change its direction.

Bumper - No! Bumpers on boats don't exist; they are on automobiles. You're thinking of Fenders that fend your vessel off piers, wharves and other objects.

Bumpkin or Boomkin - 1. A spar, similar to a bowsprit, but which projects from the stern instead of the bow. May be used to attach the backstay or mizzen sheets.   2. An iron bar, projecting out-board from a ship's side, to which the lower and topsail brace blocks are sometimes hooked

Bungee Chord - a rubber, elastic rope useful in limited rigging and stowage applications onboard a vessel; shock chord

Bunker - a compartment for the storage for the ship's fuel

Bunt - 1. the central part of a square sail

Buntline - a line tied to the bottom of a square sail and used to haul it up to the yard when furling

Buoy - an anchored float marking a position or channel, or for use as a mooring or other aid to navigation. Some have a bell, light, or whistle attached to them. A buoy with a cylindrical shape and a flat top is called a “can.” A buoy with a cylindrical shape and a conical top is referred to as a “nun.” View a downloadable and printable US Coast Guard brochure about buoys and other aids to navigation.   Also see "Buoy" at Wikipedia

Buoyage System - a formal, well established code of rules and definitions for marking shoals, harbor entrances, channels, and obstructions to permit safe shipping. View a downloadable and printable US Coast Guard brochure about buoys and other aids to navigation.

Buoyancy - the degree to which an object floats in a fluid

Buoyancy Jacket or Vest - a vest or jacket that will keep a sailor afloat in the water; not as bouyant or safe as a bulkier life jacket which is designed to hold a person's head out of the water; even if unconscious

Burdened Vessel - the vessel that must "Give Way" in a right of way situation

Burgee - a yachting pennant of any shape, but usually either pointed or swallow tailed and identifies either a ship's owner or a sailing organization. Yacht clubs and their members may fly their club's burgee while underway and at anchor, day or night, but not while racing. Modern sailing vessels fly the burgee from a lanyard under the starboard spreader on the mast, while older sailing vessels fly the burgee from the main masthead. Power boats fly the burgee off a short staff on the bow.

Burton - a light tackle having double or single blocks, used to hoist or tighten rigging.   See Block on this page

Butt Block - a wooden block fastened behind a butt joint to add strength

Butt Joint - a point where two planks join each other without scarfing or overlapping

Buttocks - in a lines plan; the contour lines that represent the vertical, lengthwise slices through surface of the hull of a vessel

Button - a raised ring around the upper part of the leather on the loom of an oar to keep the oar from sliding out through the oarlocks   See Oar

Button Knot - a type of knot in which the end of the line, after forming a knob, passes out of the same end of the knot it entered. There are several button knots.

By the Board - said of anything that has gone overboard

By the Head - a term applied to a vessel when she is deeper forward than aft

By the Lee - sailing with the wind coming from behind, and slightly to the side that the sails are on; usually a risky situation because it increases the likelyhood of an unintended and dangerous hard and violent jibe

By the Stern - a term applied to a vessel when she is deeper aft than forward

By the Wind - sailing close hauled or beating


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C     (TOP OF PAGE)     (Sailboard Diagram)     (Sailboat Diagram)     (Warship Diagram)

Cabin - an enclosed room on a deck or flat offering accommodations for passengers or crew. Compare to Saloon

Cabin Cruiser - a small power boat that has accommodations for passengers and/or crew

Cabin Sole - the floor of the cabin

Cable - 1. a very large rope; greater than 10 inches in circumference   2. a wire rope   3. a measure of length or distance equivalent to (UK) 1/10 nautical mile, approx. 600 feet; (USA) 120 fathoms, 720 feet (219 m); other countries use different values.   4. a ship's rode or anchor line.

Cable Laid - twisted nine-strand rope made by twisting three rope parts, each part consisted of a twisted three-strand rope

Caboose or Camboose - 1. a wooden deck structure housing the ship's galley   2. a cooking stove and forge sometimes located on the gun deck

Cabotage - the act of trading between the ports along the coast of a single nation

Cackling - See Keckling

Cadet - 1. a student in training at a naval academy   2. a rank of student officer aboard a training ship

Caique - 1. a light rowing boat common in the Bosporous   2. a small sailing boat used in the Eastern Mediterranean

Calm - a weather situation with no wind and no seas

Cam Cleat - a tensioning device for a line that has opposing, parallel, spring loaded, movable cams with teeth to grip the line pulled through them and hold the tension on the line, and from which the line can be easily and quickly freed by pulling on the line and lifting it out of the jaws. Also called by the ambiguous name, "Line Stopper".   Compare to "Clam Cleat"

Camber - the convex curvature of a sail or deck.

Camber Induced Sail - a sailboard sail that has internal or external camber inducers to help properly shape the sail

Camber Inducer - a mechanical device, usually inside the mast sleeve of some sailboard sails that the fore (luff) end of a batten fits into and either wraps around or partially wraps around the mast, keeping the fore end of the batten centered on the mast, thus enabling tension on the batten to create a forced, semi-rigid, camber (curvature) in the sail.

Can - a type of navigation buoy, the above-water portion of which is in the shape of a cylinder. View a downloadable and printable US Coast Guard brochure about buoys and other aids to navigation.

Canal - an artificial waterway that has been dug, dredged or constructed to carry vessels

Canister Shot - a type of anti personnel cannon load in which lead balls or other loose metallic items were enclosed in a tin, wooden, or iron shell. On firing the shell would disintegrate releasing the smaller metal objects. Canister shot pretty well replaced Grapeshot in the early 19th century. The canister gave improved range, better dispersal and allowed higher velocity powder loads.   See also Grapeshot, Cannon Balls, Chilled Shot and Chain Shot.

Cannon Balls - Solid, round projectiles fired from a cannon in order to sink, dismast, and do other structural damage to one's enemy's ship, along with killing him, if possible. Cannon balls were fired at great distance, but as vessels grew nearer, Chain Shot was substituted in order to dismast and destroy rigging on the enemy's vessel, then Canister Shot, or Grapeshot were substituted at close range.

Cant - a cut made in the body of a whale behind the neck and used for hauling the body on board

Canting Ballast Twin Foil (CBTF®) - technology that differs from a canting keel system in that the boat has twin rudders-one forward of the canting keel strut and one aft of the keel strut. The "rudders" perform the function of both the keel and rudder on a normal fixed keel boat relieving the canting keel strut of having to produce mostly lateral resistance.

Canting Keel - a form of sailing ballast, suspended from a rigid canting strut beneath the boat, which can be swung to windward of a boat under sail, in order to counteract the heeling force of the sail. The canting keel must be able to pivot to either port or starboard, depending on the current tack. The purpose of the canting keel is to allow the boat to develop righting moment when level, by swinging the keel to windward independent of the boat's angle of heel. With the canting keel handling the ballast functions, lateral resistance and steering can be managed separately with a foil (or pair of foils fore and aft). This allows for much quicker maneuverability than traditional keelboats, with about half the weight usually required for ballast.

Cant Purchase - a long block and tackle arrangement mounted at the head of the mainmast and leading to a whale alongside and used for hauling the carcass aboard. The weight of the whale on the tackle would cause the ship to lean (cant)

Cant Timbers - heavy frames at the bow and stern that are not perpendicular to the keel, but rather radiate at an angle to support the curving topsides of the hull

Canvas - 1. a tightly woven fabric, originally made of hemp, linen, then cotton, used for sails and awnings. New sails are usually made of Dacron and Nylon or composits.   2. all encompassing term for a set of sails

Cape - a promontory or headland protruding into a body of water

Capping - the fore-and-aft finishing piece on top of the clamp and sheer strake, at the frame heads, in an open boat

Capsize - 1. to turn a boat over.   2. for a knot to fall apart or come undone   3. to turn a knot inside out

Capstan - 1. a vertical drum, revolving on a spindle, used for reeling in heavy line or chain.  2. During the "Age of Sail", a large round hub, on a vertical axis, that sat on an upper deck and drove the windlass on a lower deck via a shaft in order to raise the anchor. Removable levers, known as Bars, were inserted into the capstan for men to push on as they walked around the capstan to raise the anchor. Some larger ships had two capstans on separate decks driving the windlass on yet another deck, in order to allow more men room to push. The anchor chain or line came up from the side of the ship, through the hawse-hole, around the windlass, then into the hold or anchor chain locker. Over time, several forms existed. See Capstan at Wikipedia for more information.

Capstan Chantey (pronounced "shan'-tee") - a rhythmic sea song with a short repetitive answering chorus, sung by the crew as they trod around the capstan pushing on the bars to raise the anchor or other heavy object. The rhythm helped them to act in unison, and gave them heart for the hard work.

Captain - 1. the person on board a vessel and who is in charge of the vessel and legally responsible for it and its occupants   2. a naval officer having a rank equivalent to a full colonel

Captain of the Fleet - a temporary adjutant-general who is in charge of discipline aboard the ships of a fleet

Captain's Mast - a disciplinary hearing aboard a naval vessel at which the captain hears testimony about offences committed on the ship and administers appropriate punishment

Car - a sliding fitting that attaches to a track allowing for the adjustment of blocks or other devices attached to the car

Caravel - see Types of Sailboats

Carbon Fiber - a modern, light weight, strong, composit made of carbon fibers and epoxy used in masts and other sailing components

Cardinal Points - the four primary directions on a compass: North, East, South, and West

Careening - to cause the ship to tilt on its side, usually to clean or repair the hull below the water line. To Heave Down

Cargo - the merchandise being hauled in a merchant ship

Cargo Bay - a large open area below decks used for stowing goods

Cargo Vessel - a ship or boat designed and built for the sole purpose of carrying cargo

Carlines or Carlins - fore-and-aft aligned timbers separating deck beams

Carling - fore-and-aft beams at hatches

Carpenter's Walk - a narrow space between the hull and interior bulkheads where the ship's carpenter could inspect for damage and make repairs

Carrack - a large galleon of the 15th century. See Types of Sailboats

Carronade - a short smoothbore, cast iron cannon, developed for the Royal Navy by the Carron Company, Scotland, UK used from the 1770s to the 1860s. The carronade was designed as a short-range naval weapon with a low muzzle velocity. The lower muzzle velocity of a carronade's round shot was intended to create many more of the deadly wooden splinters when hitting the structure of an enemy vessel, leading to its nickname, the smasher. A carronade was much shorter and a third to a quarter of the weight of an equivalent long gun: a 32 pounder carronade, for example, weighed less than a ton, but a 32 pounder long gun weighed over 3 tons. Carronades were manufactured in the usual naval gun calibres (12, 18, 24, 32 and 42 pounders, but 6 pdr and 68 pdr versions are known), but they were not counted in a ship of the line's rated number of guns. The classification of Royal Navy vessels in this period can therefore mislead, since they would often be carrying more pieces of ordnance than they were described as carrying.

Carry Away - to break loose or tear off; said of gear that has exceeded its strength capabilities, as "The storm jib was just carried away."

Carved or Carving Jibe (Gybe) - any of several high speed planing jibes initiated by taking the rear foot out of the strap and placing it near the leeward rail of a sailboard, shifting weight to that rail in order to make the board turn in that direction, flipping the sail as you pass through straight downwind, then exiting the jibe, still at planing speed.  Go To "Jibe"

Carvel Built - a method of constructing a wooden boat's hull by fixing planks to a frame so that the planks butt up against each other, edge to edge, gaining support from the frame and forming a smooth hull. Such planking requires caulking between the joints over and above that needed by the Clinker Built or Lapstrake technology, but gives a stronger hull capable of taking a variety of full-rigged sail plans, albeit one of greater weight.   See illustration at Clinker Built

Cast Away - forced from a ship by disaster

Castaway - a crewmember or passenger of a vessel that survives its sinking and is left adrift or stranded

Casting Line - a heaving line

Cast Off - to release lines holding boat to shore or mooring, to release sheets

Cat - 1. To hook an anchor, with a block and tackle called the Cat, after raising it to the Cat Head, prior to securing (Fishing) it alongside or on the Billboard on deck for sea. (An anchor raised to the Cat Head is said to be Catted).   2. The cat o' nine tails.   3. A cat-rigged boat or catboat.

Catalyst - a chemical used to activate polyester resins and other polymer compounds to make them solidify

Catamaran - a sailing vessel with two hulls; usually pontoons of equal size.

Catboat - a one sail sailboat with the mast well forward, usually having a gaff rig.   Compare to other sailboat types on this page

Catch a Crab - in rowing, to miss a stroke by failing to get the oar into the water at the beginning of a stroke or by failing to withdraw it properly at the end.

Catenary - the U-shaped curve in a line or rope, made fast at both ends, due to the downward pull of gravity

Cat-harping - One of the short ropes or iron cramps used to brace in the shrouds toward the masts in order to give freer sweep to the yards.

Cat Head - a beam extending out from the hull at the bow,used to support an anchor when raised (Catted) in order to be secured (Fished). They are used to draw the anchors up to the top of the side without injuring the bow.

Cat O'Nine Tails - short nine-tailed whip kept by the bosun's mate to flog sailors (and soldiers in the Army). When not in use, the cat was kept in a baize bag, hence the term "cat out of the bag". "Not enough room to swing a cat" also derives from this.

Caulk - to fill gaps with waterproof compound or materials to make watertight

Cavitation - 1. a condition where bubbles or vacume form around a propeller allowing it to spin without resistance and making it lose its ability to drive a vessel forward.   2. a condition where air bubbles form along the windward (low pressure) side of a sailboard fin making it lose its ability to offer lateral resistance and propel the board forward

Cay (Pronounced "Kee") - one of a chain of small low lying tropical islands composed of coral or sand. Same as "Key".

Ceiling - the inside lining of the hull. Not above your head.

Celestial Navigation - determination of position, and thus, the total process of navigation based on your position, by the position of the sun, moon, and stars.

Centerboard - a retractable, sometimes removable, keel that extends from the bottom of the boat or sailboard from the centerboard case or trunk. The centerboard typically will self retract by swinging backward and upward while making headway if it hits bottom in shallow water and its angle and depth can be adjusted to lessen drag, increase stability, or increase the ability to sail upwind. The deeper it is adjusted, the more drag it creates, the more stability it creates, and the more easily the craft will sail upwind

Centerline - 1. a vertical line running from bow to stern through the middle of a craft.   2. In a lines plan of a vessel, a vertical line that represents the plane that divides the vessel in half, and from which half-breadths are measured.

Center of Effort - an invisible point on a sail where the combination of all the aerodynamic forces converge. The point where the sail "seems" to pull from. It is above the boom of a sailboard at the deepest point in the curvature of the sail. This point will move with changes in the wind velocity, downhaul tension, batten tension, and outhaul tension.

Center of Lateral Resistance - a point on the bottom of a watercraft where the combination of all the hydrodynamic forces converge. It is in the center of the keel or of the centerboard when the centerboard is down and near the fin or skeg on a sailboard if a centerboard is not down

Certificate - an official government paper, such as a seaman's, boat's, or master's license, allowing the operation of a commercial vessel

Chafe - damage to a line caused by rubbing against another object

Chafing Gear - Cloth, tape, baggywrinkle or other material attached to lines or other rigging to avoid abrasion

Chain Locker - storage space for the anchor chain and rode

Chainplate - metal plate with an eye, bolted to the deck or side of a gunwale, to which standing rigging is attached

Chain Shot - Cannon balls linked together with a chain and fired in order to do structural damage to the enemy's rigging and masts.   Compare to Grapeshot, Cannon Balls, Canister Shot

Chain Wale or Chain Wail or Channel - a horizontal timber or ledge built outboard from the side of a sailing vessel to spread shrouds and backstays outward. There may be fore chain wales, main chain wales and aft or quarter chain wales.

Chandlery - 1. nautical items   2. the stores where nautical wares are sold

Chantey or Chanty or Shanty - a shipboard song, or chant primarily on merchant ships during heavy work, such as turning the capstan or hoisting a sail, to help coordinate the men's efforts and to pass the time

Channel - 1. the navigable portion of a waterway where there is a known depth of water. Boats may not normally anchor in a channel   2. a horizontal timber or ledge built outboard from the side of a sailing vessel to spread shrouds and backstays outward. There may be fore channels, main channels and aft or quarter channels.

Chart - a nautical map

Chart No. 1 - a booklet prepared and distributed by the National Oceanic Survey that shows all the symobls and abbreviations approved and used by the U.S. government on its nautical charts

Charted Visibility - the extreme distance, shown in numbers on a chart, at which a navigational light can be seen under standard conditions

Chase Guns - Cannons mounted on the bow or stern of a ship. Those on the bow could be used to fire upon a ship ahead, while those on the rear could be used to ward off pursuing vessels.

Cheeks - 1. Wooden blocks at the side of a spar.   2. The sides of a block or gun-carriage.

Chess Tree - a piece of wood fastened with iron bolts on each top-side of the ship. Used for boarding the main-tack to, or hauling home the clews of the main-sail or course, for which purpose there is a hole in the upper part, or deadeyes or blocks attached, through which the tack passes, that extends the clew of the sail to windward. Where chain has been substituted for rope, iron plates with thimble-eyes are used for chess-trees.

Chicken Jibe (Gybe) - turning a fore-and-aft rigged vessel upwind and tacking through more than 180 degrees to avoid having to jibe on a downwind course. While much slower, this technique avoids the dangers of passing the boom across the boat under load. This is the opposite of a square rigged vessel "Wearing Ship".   Go To "Jibe"

Chilled Shot - cannon balls made of very rapidly cooled cast-iron, i.e. cast in iron moulds, and thus found to acquire a hardness which renders them of nearly equal efficiency with steel shot for penetrating iron plates, yet produced at about one-quarter the price. They invariably break up on passing through the plates, and their fragments are very destructive on crowded decks; though in the attack of iron war vessels, where the demolishment of guns, carriages, machinery, turrets, etc., is required, steel shot is superior.   Compare to Grapeshot, Cannon Balls, Chain Shot, and Canister Shot

Chine - 1. A relatively sharp angle in a hull, as compared to the rounded bottoms of most traditional boat hulls.   2. A line formed where the side panels of a boat meet the bottom panels. Soft chine is when the two sides join at a shallow angle, and hard chine is when they join at a steep angle. Chine is not seen on round bottom vessels.

Chine Log - an internal, longitudinal timber that runs from stem to stern at the chine of a vessel

Chip Log - a simple, old, speed measuring device consisting of a wooden board, in the shape of a quarter circle, attached to a line (the log-line). The log-line has a number of knots tied in it at uniform, measured, spacings. The log-line is wound on a reel to allow it to be paid out easily in use. The Chip is thrown overboard at the stern of the vessel and as the line pays out, it is timed, thus the speed of the vessel can be calculated. The log-line is attached to the board with a bridle of three lines connected to the vertex and to the two ends of the quadrant's arc. In order to ensure that the log submerges and is oriented correctly, the bottom of the log is weighted with lead. This provides for more resistance in the water and a more accurate and repeatable reading of speed. The bridle is attached in such a way that a strong tug on the log-line results in one or two of the bridle's lines releasing, allowing the log to be retrieved with relative ease.   See Chip Log at Wikipedia.   Compare to Dutchman's Log and Taffrail Log

Chock - a guide or fairlead for an anchor, mooring or docking line, attached to the deck   See illustration at Deck Fittings on this page

Chock-a-Block - rigging blocks that are so tight against one another that they cannot be further tightened   Sometimes called Two-Blocked

Chop - a series of small waves that tend to make your ride rough or "choppy."

Chord - an imaginary straight line drawn between the luff and the leech of a sail and parallel to the water's surface. Used for describing sail shape.

Chronometer - a ship's clock. Before GPS units were used, these needed to be extremely accurate on long voyages in order to determine a ship's longitude

Chute - another name for Spinnaker Derived from "parachute" because of their similar appearance.

Civil Twilight - See Twilight

Clam Cleat - a tensioning device for a line that has opposing, stationary teeth in a "V" or "Wedge" configuration to grip the line pulled through them and hold the tension on the line. Also called by the ambiguous name, "Line Stopper".   Compare to "Cam Cleat"

Clamp - a main longitudinal strengthening member under the deck in decked-over boats that acts as the bearer of beams and joints, and at the gunwale in open boats

Classes - organized groups for racing boats that are either of identical specifications and measurements, or have variable measurements and fit a formula, designed to compensate for boat performance, and thus, put a premium on skill and tactics

Claw Off - to beat to windward away from a lee shore

Cleat - a horned, stationary fitting used to secure a line   See illustration at Deck Fittings on this page

Clenched Nail - a nail whose tip has been bent back into the wood to lock it in place; most often used in lapstrake planking

Clevis Pin - a cylindrical pin that secures one fitting to another

Clew - the lower aft corner of a sail, where the leech meets the foot, and where the outhaul or sheet is tied and is adjusted. On a square rigged sail, the lower corners of the sail. Square sails have sheets attached to their clews like triangular sails, but the sheets are used to pull the sail down to the yard below rather than to adjust the angle it makes with the wind. Sails hang from a yard on a square rigger and the yard is swung about to alter its angle to the wind with its braces.

Clew First - sailing with the sail of a sailboard reversed; clew ahead of the mast

Clewgarnets - tackles attached to the clewlines of square sails, on the yards above, used to truss up or clew up the sails (i.e. to pull the clews up onto the upper yard or the mast in preparation for furling the sail).

Clew Lines - lines attached to the clews of square sails and to the yards above, used to truss up or clew up the sails (i.e. to pull the clews up onto the upper yard or the mast, using the clewgarnets, in preparation for furling the sail).

Clinker Built or Lapstrake
Compared to Carvel Built Hulls
A line drawing showing the difference between Clinker Built/Lapstrake and Carvel Built Hulls

Clinker Built - a method of constructing hulls of boats and ships by fixing wooden planks and, in the early nineteenth century, iron plates to each other so that the planks overlap along their edges. The overlapping joint is called a land. In any but a very small boat, the individual planks will also be joined end to end; the whole length of one of these composite planks is a strake. Same as "Lapstrake"   Compare to Carvel Built.

Clipper - a very fast sailing ship of the 19th century that had multiple masts and a square rig. They were generally narrow for their length, could carry limited bulk freight, small by later 19th century standards, and had a large total sail area. While traditional merchant ships were accustomed to average speeds of under 5 knots (9 km/h; 6 mph), clippers aimed at 9 knots (17 km/h; 10 mph) or better. Some could reach 20 knots (37 km/h; 23 mph). The fastest recorded speed for any sailing vessel during this time was a clipper, Sovereign of the Seas, traveling at 22 knots (41 km/h; 25 mph) in 1854. Clippers were built for seasonal trades such as tea, where an early cargo was more valuable, or for passenger routes. The small, fast ships were ideally suited to low-volume, high-profit goods, such as spices, tea, people, and mail. Given their speed and maneuverability, clippers frequently mounted cannon or carronade and were often employed in piracy, privateering, smuggling, or interdiction service.

Clipper Bow - the sharp bow of a vessel whose stem creates a concave curve and projects outboard

Close Aboard - not on, but near a vessel

Close Hauled - a point of sail where the boat is sailing as close to the wind as effectively possible without luffing the sails or becoming in irons. Maximize window at Points of Sail Illustration to see more detail.(Opens in new window)

Close Reach - a point of sail where the boat is sailing towards the wind but is not close hauled or in irons. Maximize window at Points of Sail Illustration to see more detail.(Opens in new window)

Close-Winded - a vessel that is capable of sailing very well upwind

Closing the Gap - sailing a sailboard in high winds with the mast raked back so the foot of the sail almost touches the deck of the board.

Clove Hitch - a simple hitch used to tie a line to a post. Effective in its purpose, but spills easily. It should be finished with at least one half hitch over the standing end of the line, if not two. The Clove Hitch is one of the eight most useful knots a sailor needs to know.

Club - 1. a boom for a jib on a vessel so rigged.   2. a spar laced to the foot of a jib, or sometimes to the after edge of a quadrilateral, fore-and-aft rigged sail like that on a log canoe.

Club Footed Jib - a jib with boom or "club" on the foot of the sail

Club Hauling - a maneuver in which a ship drops one of its anchors at high speed in order to turn abruptly. This was sometimes used as a means to quickly get a good firing angle on a pursuing vessel.

Coaming - the raised edge around a hatch, cockpit or skylight that helps keep water on deck from running below

Coastal Current - an ocean current flowing roughly parallel to a coast, outside the surf zone

Coastal Refraction - a small change in the direction of travel of radio waves as they cross a shoreline obliquely

Coaster - a vessel that stays near land rather than venture out to sea

Cockbill - a yard having one yardarm cocked higher than the other

Cockpit - the area, below deck level, that is somewhat more protected than the open deck, from which the tiller or wheel is handled

Coffee Grinder - a geared, pedistal mounted hand crank, similar to the pedal crank on a bicycle, that drives a winch. A coffee grinder may be used by one person, or two people that are facing each other. This geared system offers a lot of power enabling sails to be trimmed quickly.

Coil or Coil Down - to lay a rope in a loose, stacked spiral on the deck. To coil down a line, a large turn of the standing or bitter (secured) end of the line is made on the deck and successive turns are made on top of each other until all the line has been used, making sure to keep out kinks, and laying the bitter end on the outside of the coil. The whole coil is then carefully capsized (turned over) leaving the standing end clear for running.   Compare to Fake Down and Flemish Flake

Collar - the reinforced opening in the deck or cabin roof through which the mast passes, designed and constructed to take the lateral strain of the mast. Called "Gate" on smaller vessels and "Partners" on larger vessels

Collier - a historical term used to describe a bulk cargo ship. In the late 18th century a number of wooden-hulled sailing colliers including HMS Adventure, HMS Discovery, HM Bark Endeavour, and HMS Bounty, gained fame after being adapted for use in voyages of exploration in the South Pacific, for which their flat-bottomed hulls and sturdy construction made them well suited.

COLREGS - The International Regulations for Preventing Collision at Sea, also known as the Rules of the Road or International Navigation Rules, are a set of statutory requirements designed to promote navigation safety while in outer coastal waters and on the high seas. These rules include requirements for navigation lights, dayshapes, and steering as well as sound signals for both good and restricted visibility. They are similar to, but slightly different from the Inland Rules in the wording and in the signals that vessels must use. An entirely different set of rules apply when boats are racing, previously called the International Yacht Racing Rules before 1996, and now, the Racing Rules of Sailing, created by the International Sailing Federation (ISAF).

Combers - long curling waves

Come About - to Tack; to change course by turning the bow into the wind so that the wind comes from the other side of the boat. In sailboarding, this is usually the first turn taught to beginners. It requires the sailor to move forward and around the mast to the other side of the sailboard as the board passes through the eye of the wind.

Companion Ladders or Companionways - ladders or stairways leading below

Compass - a navigation instrument, either magnetic (showing magnetic north) or gyro (showing true north)

Coordinated Universal Time See Universal Time, Coordinated

Cordage - rope or line

Coriolis Force - an apparent force acting on a body in motion, due to rotation of the earth, causing deflection to the right in the northern hemisphere and to the left in the southern hemisphere

Corrector - a magnet, piece of iron, or device to counteract the built in deviation of the ship's compass

Corsair - a pirate or privateer

Counter - The part of the stern above the waterline that extends beyond the rudder stock, culminating in a smaller transom. A long counter increases the waterline length when the boat is heeled, so increasing hull speed

Countercurrent - a secondary current flowing adjacent to and in the opposite direction of another current

Counter Timber - a fore-and-aft structural member of the hull sloping up and backwards from the keel to the transom to support the overhang of the counter. Also called the Horn Timber

Coupler - a devise for attaching the tongue of a trailer to the hitch of a vehicle

Course - the intended direction of travel expressed as an angular distance from 0° at North clockwise through 360°.   Compare to Course Made Good, Heading, and Track

Course Error - the angular difference between the course and the course made good

Course Made Good - the single, resultant, direction of actual travel from the point of departure to the point of arrival (which may not be the destination if you calculated wrong), expressed as an angular distance from 0° at North clockwise through 360°.   Compare to Course, Heading, and Track

Course of Advance - the course expected to be made good over the ground

Course Over the Ground - the course actually made good over the ground

Courses - the lowest square sail on each mast - The mainsail, foresail, and the mizzen on a four masted ship (the after-most mast usually sets a gaff driver or spanker instead of a square sail)

Courtesy Flag - a small version of the flag of the country being visited; flown from the starboard spreader

Cover - In racing, to stay between your opponents and the next mark

Covering Board - the outermost, wide, fore-and-aft running deck plank on either side of a vessel; covering much of the length of the top edge of the hull, the ends of the frames, and the top edge of the sheer clamp

Cowl - the horn-shaped top of a ship's ventilator

Coxswain or cockswain (Pronounced "cox'n") - The helmsman or crew member in command of a boat

CQR - Coastal Quick Release - (also a poor pun on the word Secure) - a popular plow type anchor design.

Crab - a pedestal mounted abaft the mast; used in place of a gooseneck fitting on some catboats

Crab Claw or Crabclaw - an isosceles triangular sail with, sometimes very curved, spars along upper and lower edges that are tied down at the bow, and switched from one end of the boat to the other when shunting (tacking) and have a shorter, sometimes very concave curved, leech. The upper spar or yard is attached to the mast, but the bottom spar is not and the crab claw pivots around the leading edge spar. The mast is mounted in the larger hull (Vaca) of a Proa or other, similar vessel.

Cradle - a framework to support vessels in the vertical position when they are out of the water

Crance/Crans/Cranze Iron - a fitting, mounted at the end of the bowsprit to which stays are attached

Cringle - A circular eye, made of rope, metal, etc., usually sewn into the corners or luff of a sail, for attaching the sail to a spar.

Crossbeams - the akas or connecting framework between the hulls of a catamaran

Crosscut Sails - a sail manufacturing technique, first implemented by Nathanael Herreshoff in the mid 1800's, whose seams run at right angles to the leech; as opposed to paralleling the leech, as had been done for centuries prior to that time. Cross cut sails stretch less and allow smoother airflow across the fabric.

Cro'jack or crossjack - a square yard used to spread the foot of a topsail where no course is set, e.g. on the foremast of a topsail schooner or above the driver on the mizzen mast of a ship rigged vessel

Crosstrees - 1. horizontal pieces of wood or metal that cross the mast athwartships near the top of a mast, acting as spreaders for the shrouds of the mast section above it. Masts of a square rigger are made in sections in case the mast breaks, so that only that section need be replaced. It would be nearly impossible to replace a wooden one-piece mast the full height of square rigged ship, much less carry spares onboard. See at Mast   2. Spreaders

Crow's Nest - a structure built on the mainmast masthead, constructed with sides and sometimes a roof to shelter a lookout from the weather. Until the invention of radar, having a man in the crow's nest was the best way to view other ships, land, or approaching hazards

Crutch - a support for a spar when the spar is not in use

Cuddy - a small cabin in a boat

Culverin - a light, long barreled cannon used in the 16th and 17th centuries used to bombard targets from a distance. The culverin fired solid cannon balls with a high muzzle velocity, producing a relatively long range and flat trajectory.

Cunningham - a grommeted hole in the luff of a sail, just above the tack, through which an easily adjustable line that controls the downforce on the luff of the mainsail is run in order to flatten the sail; a type of downhaul

Cuntline - 1. the spiral "valley" between the strands of a rope or cable. Before serving a section of laid rope e.g. to protect it from chafing, it may be "wormed" by laying yarns in the cuntlines, giving that section an even cylindrical shape   2. the space between casks or barrels stowed side by side

Cunt splice - A join between two lines, similar to an eye-splice, where each rope end is joined to the other a short distance along, making an opening which closes under tension

Current - the horizontal movement of water. Compare to Tide

Cutback - a maneuver a sailboarder makes during wave sailing that involves climbing the face of a wave then making a sharp turn near the lip of the wave and heading back down the face.

Cut and Run - When wanting to make a quick escape, a ship might cut lashings to sails or cables for anchors, causing damage to the rigging, or losing an anchor, but shortening the time needed to make ready by bypassing the proper procedures

Cut of His Jib - The "cut" of a sail refers to its shape. Since this would vary between ships, it could be used both to identify a familiar vessel at a distance, and to judge the possible sailing qualities of an unknown vessel

Cutter - 1. a single masted, fore-and-aft rigged vessel that has the mast stepped further aft than the conventional sloop, about two-fifths of the way aft measured on the water line, allowing for larger jibs. They usually sail with an inner staysail and an outer jib.   2. a ship's boat having double-banked oars and one or two lugsails.   3. Also, a revenue cutter; a lightly armed government vessel used to prevent smuggling and enforce the customs regulations.   4. A U.S. Coast Guard Cutter - the Coast Guard calls any CG vessel 65 feet in length or greater, having adequate accommodations for crew to live on board, "Cutters".   Compare to other Types of Sailboats on this page

Cutwater - the leading edge of the stem; the part that cuts or separates the water when the ship is in motion. A False Stem

Cyclone - a large-scale, atmospheric wind-and-pressure system characterized by low pressure at its center and by circular wind motion, counterclockwise in the Northern Hemisphere, clockwise in the Southern Hemisphere   See also: Typhoon and Hurricane


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Dacron - a trademarked name for a type of polyester used in sails and lines that was developed in the 1950s. It is strong, light, impervious to rot, stretches little, is supple and has a high resistance to sunlight. Dacron sails can be precisely cut and hold their shape well, thus most modern working sails are made of this material. Also called Terylene in some parts of the world.   See Polyester

Daggerboard - a removable keel that is inserted straight down from the top, through a slot in the deck, through the bottom of a boat or sailboard. It typically needs to be raised manually to avoid damage when running aground in shallow water, since a daggerboard will not pivot back when it hits an object like a centerboard will.

Dan Buoy - a locator buoy consisting of a ballasted float carrying a staff which supports a flag or light, typically employed to show the location of a worksite, the end of a fishing net or a man overboard.

Danger Angle - a piloting angle, on which both chart and the water, a measured angle between two points - such as buoys, obstacles, or landmarks - indicates to a sailor an unsafe limit to his vessel

Danger Buoy - a buoy marking an isolated danger to navigation. View a downloadable and printable US Coast Guard brochure about buoys and other aids to navigation.  

Dangerous Semicircle - that half of a cyclonic storm area to the right of the storm track in the northern hemisphere, and to the left in the southern hemisphere. In this semicircle, the winds are stronger and tend to blow a vessel into the path of the storm

Click on IMAGE to open in new window and enlarge.
DANGER ZONE !!!
YOU MUST GIVE WAY TO VESSELS IN BLACK DANGER ZONE
An illustration showing when YOUR vessel must GIVE Right of Way when approaching another vessel

Danger Zone - the angular area from Dead Ahead to Two Points Abaft the Starboard Beam of your vessel. Other vessels in this Danger Zone have the Right of Way over you and YOU MUST Yield Right of Way to and steer clear of them. Vessels approaching your course and not in your Danger Zone should yield Right of Way to you.

Davit - a rotating crane able to project over the sides of a vessel in order to hoist heavy articles or weights, such as lifeboats, tenders, anchors, or stores; frequently used in pairs

Davy Jones' Locker - An idiom for the bottom of the sea

Daybeacon - an unlighted fixed structure which is equipped with a dayboard for daytime identification. View a downloadable and printable US Coast Guard brochure about daybeacons and other aids to navigation.

Dayboard - the daytime identifier of an aid to navigation presenting one of several standard shapes (square, triangle, rectangle) and colors (red, green, white, orange, yellow, or black) marking channels, obstructions, etc. Range Dayboards, which are usually shore-mounted, come in pairs to help the vessel operator maintain a straight and safe course within a navigable channel. Each member of the pair is separated from the next in distance and elevation, with the one in front shorter than the one behind it. When the two appear to be vertically stacked, the vessel is on the range line.View a downloadable and printable US Coast Guard brochure about dayboards and other aids to navigation.

Day Sailer - 1. an open sailboat   2. a small to medium sized sailboat not intended to be used for extended cruising

Dayshape - a geometric shaped marker, such as a cone, ball, or cylinder used onboard ship during daylight hours to indicate a vessel's condition, type, or occupation according to the Rules of the Road

Day's Run - the distance traveled by a vessel in one day, usually reckoned from noon to noon

Dead Ahead - bearing 000°, relative; straight in front of the vessel

Dead Astern - bearing 180°, relative; directly behind the vessel

Click on IMAGE to open in new window and enlarge.
A Pair of Triple Deadeyes
A photograph of a pair of Triple Deadeyes in use onboard a square rigged sailing ship.

Deadeye - a round, thick wooden disc with one or more holes through it, perpendicular to the plane of the disc, and through which a lanyard or line is run, used in the standing and running rigging of traditional sailing ships; used as a less expensive stand-in for a block and tackle which has rotating sheaves that greatly reduce friction and wear on the line. Single and triple-hole deadeyes are most commonly seen.
     Single deadeyes (or bull's eyes) are used to guide and control a line and, particularly in older vessels, to change its direction. More modern systems would use a block for this purpose but in traditional rigs with many lines to deal with, designed when blocks were relatively expensive to make, a deadeye provided an acceptable compromise.
     Triple deadeyes are used in pairs; a line called a lanyard is run back and forth between them, through the holes, so that they function again much as a block and tackle would. This provides a mechanical advantage, pulling harder on whatever the deadeyes are attached to. Pairs of deadeyes are placed in the shrouds (the lines that hold up the mast), where they are used to create greater tension in the shrouds.
     In recent decades, as steel wire became the prevalent material for sailboat rigging, deadeyes and laynards gave way to metal turnbuckles for tensioning the wires. More recently, however, with the advent of high-strength and low-stretch synthetic fibres, some sailboats are using synthetic rope for standing rigging, and deadeyes and lanyards are coming back into use as tensioning devices

Deadlight - pieces of thick, transparent glass or plastic, fixed in the decks or sides of a vessel to admit light. Unlike "portlight" portholes, they have cannot be opened for the flow of air.

Deadman - a line that has come free of its cleat and is thrashing in the wind or dragging in the water, a very embarrassing example of poor seamanship

Dead Reckoning (DR) - the process of estimating one's current position based upon a previously determined position, or fix, and advancing that position based upon known speed, elapsed time, and course; without sightings to land, etc. The speed reading was originally based on a Dutchman's Log, which uses a buoyant object tossed overboard near the bow of the vessel and assumed to be "Dead" in the water, or stationary, and the time it takes for the boat to move by it a certain, measured, distance on the deck is timed, then the speed of the vessel can be calculated. This does not take into account effects of wind and currents on the calculated position of the vessel.   Compare to Ded Reckoning and Fix.

Deadrise - the angle above horizontal of the bottom from the centerline (keel) to the chine, measured in degrees. A flat bottomed boat would have zero deadrise. Deadrise is typically measured at the transom. If measured at some other point, that point should be specified. "Midship Deadrise Angle" is the angle, taken at midship, at which the hull slopes up from horizontal. The deadrise can vary dramatically along the hull, very acute at the bow, to very small angles at the stern.

Dead Slow - the speed a vessel will make through still water with its propulsion continuously engaged at engine idle speed   Compare to Wakeless Speed and Bare Steerage Speed

Deadwood - a heavy reinforcment of the keel mounted on top of the keel of a vessel to afford a firm fastening for the frames and to attach the keel to the stem and/or sternpost

Death Roll - In a keel boat, a death roll is the act of broaching to windward, putting the spinnaker pole into the water and causing a crash-gybe of the boom and mainsail, which sweep across the deck and plunge down into the water. The Death Roll often results in destruction of the spinnaker pole and sometimes even demasting of the boat. Serious injury to crew is possible due to the swift and uncontrolled action of the boom and associated gear sweeping across the boat and crashing to the (now) leeward side.

Deck - an approximately horizontally surface that is a structural part of a ship. This is the part you stand on. Compare to Flat

Deck Beams - timbers that run athwartships and support the decks

Deck Fittings
Deck fittings for sailing vessels

Deck Fittings - hardware mounted on the deck for making lines, shrouds, or stays fast or changing the direction of lines

Deck Log - a written record of the movements of a vessel with regard to courses, speeds, positions, and other navigational information, and important events aboard the vessel. Also called "Ship's Log"

Declination - angular distance north or south of the celestial equator; the arc of an hour circle between the celestial equator and a point on the celestial sphere, measrued northward or southward from the celestial equator through 90°, and labeled N or S to indicate the direction of measurement

Ded Reckoning or Deduced Reckoning - the process of estimating one's current position based upon a previously determined position, or fix, and advancing that position based upon known speed, elapsed time, and course, along with currents and effects of wind (leeway).   Compare to Dead Reckoning.

Deadrise - the angle with the horizontal made by the outboard rise of the bottom of a vessel at the widest frame

Deep V - a hard chine power boat having a 15 degree or more angle deadrise at the transom

Depth - the vertical distance, measured inside the hull, from the bottom or floors to the deck. Used as a measure of storage space on larger vessels   Compare to Draft and Headroom

Depth Contour - a line connecting points of equal depth on a chart

Depth Finder - an electronic device that uses Sonar to determine the distance from the hull to the bottom of the body of water. Compare to Sounding Line

Depth Sounder - a "Depth Finder"

Delaminate - to have the outer layer (skin) of a sailboat or crafts hull separate from its adjoining layer

Depower - to reduce heeling force by changing sail trim

Derelict - a vessel or cargo abandoned in open water by its crew without any hope or intention of returning.   Compare to Jetsam and Lagan or Ligan and Flotsam and Marine Debris

Deviation - a deleterious influence on compass readings caused by magnetic objects near the compass that need to be corrected for to make the needle point directly to magnetic north. These may be parts of a vessel, other objects, temporary or permanent, or the vessel itself. Compare to Variation. Also See: Corrector

Diagonals - in the lines plan of a round bottomed boat, the set of lines corresponding to slices made at various angles down from varying points on the center line to the outside of the hull. The distances from the center line to the intersection of the diagonals and the sections are used to check the accuracy of the hull being created compared with the lines plan.

Dinghy - 1. a small, open boat, often carried by a larger vessel to act as a tender.   2. a small, open sailing boat

Directional Light - a light illuminating a sector or very narrow angle and intended to mark a direction to be followed

Displacement - the weight of the water displaced by a watercraft as it sits in the water

Displacement Hull - a vessel's hull that is designed to ride through the water, pushing the water down and outward as it travels rather than riding on top of the water's surface.

Ditty Bag - a small bag for personal items or tools

Diurnal - having a period of, occurring in, or related to once a day

Diurnal Current - tidal current having one flood current and one ebb current each tidal day

Diurnal Inequality - the differnece between the heights of the two high tides or two low tides during the tidal day, or the difference in speed between the two food currents or the tow ebb currents during a tidal day

Diurnal Tide - tide having one high tide and one low tide each tidal day

Dividers - an instrument consisting, in its simple form, of two pointed legs jioned by a pivot, used principally for measuring distances or coordinates on a chart or map

Dock - 1. a landing pier.   2. an enclosed or nearly enclosed water area for working on or loading and unloading vessels.   3. the act of taking the boat to a pier to secure it

Dodger - a frame-supported, covered structure, sometimes with windows, providing a helmsman and other occupants of the cockpit of a sailboat partial protection from harsh weather and seas. It covers part of the cockpit and the entrance (or "companionway") into the interior of the sailboat. One can usually stand under a dodger and be protected from rain, spray and snow travelling straight down or from the front and sides of the craft, but there is little protection afforded from elements moving from aft forward. A similar type of shelter on a boat, but without the forward and side protection, is called a Bimini top.

Dog - a lever-like handle found on hatches and bulkhead doors, that when turned, force the unit to be water tight

Dog Vane - a small wind vane placed on the truck or above the rail and within the view of the helmsman

Dog Watch - the duty watch from 4:00 P.M. to 8:00 P.M. The purpose of the Dog Watch is to shift the watches each night, so that the same watch shall not be on deck at the same hours throughout a voyage. In order to effect this, the watch from four to eight P.M. (the Dog Watch) is divided into two half-watches, one from four to six p.m., and the other from six to eight p.m. By this means they divide the twenty-four hours into seven watches instead of six, and thus shift the hours every night. The choice of time also allows both watches, if there are only two, to eat an evening meal at about the traditional time, usually at two bells (5:00 P.M.) (1700 hours) during the First Dog Watch, and at the change of the watch at four bells (6:00 P.M.) (1800 hours) (beginning of Last Dog Watch).

Dogged Down - to have the thumb screws or other tightening devices, as on a hatch, tightened

Doldrums - a band circling the earth at or near the equator, created by the convergence of the opposing winds of the northern and southern hemispheres and known for its erratic weather patterns with large areas that lackwind punctuated with violent thunderstorms. The area of the Doldrums moves farther away from the equator during the Northern summer than the Southern summer due to the concentration of the continents north of the equator. Early sailors named this belt of calm "the doldrums" because of the inactivity and boredom they found themselves in after days of no wind; often towing their ships with their oar-powered ship's tenders toward any winds they could find. To be becalmed in this region in a hot and muggy climate could mean death in an era when wind was the only effective way to propel ships across the ocean. Even today leisure and competitive sailors alike attempt to cross the zone as quickly as possible as the erratic weather and wind patterns may cause many days of delays.
      A more modern name for the Doldrums is the "Intertropical Front" (ITF) (1920s - 1940s), but after the recognition in the 1940s and 1950s of the significance of wind field convergence in tropical weather production, the term Intertropical Convergence Zone or "ITCZ" came into use. When it lies near the equator, it is called the near-equatorial trough.   See illustration at Prevailing Winds of the World

Dolphin - a piling or nest of pilings bound together off a wharf or beach, or off the entrance to a dock, for use in mooring or having navigational markers mounted on it.

Dolphin Striker - a spar pointed downward from the bow of a boat, supporting the martingale, to strengthen the bowsprit.

Dopler Effect - the apparent change in frequency of radiant energy when the distance between the source and the observer or receiver is changing, as when the sound of a train's whistle changes pitch as the train approaches or recedes.

Dorade Vent - a ventilation opening with a cowl on deck and a box designed to keep water out while allowing air to pass below

Double Banked - a rowing arrangement having two oarsmen per thwart, each pulling an oar on opposite sides

Double Ended - having bow and stern shaped almost the same; as in a canoe or whaleboat

Double Headsail Rig - a vessel with two sails forward of the mast as on a cutter

Double Planking - a planking method in which two staggered layers of carvel laid planks make up the hull. Perhaps the strongest and most lasting of various planking methods.

Douse - to lower quickly, as in dousing a sail

Dousing Sock - a device used to make the launching and retrieval of a spinnaker a much easier task. The dousing sock is a long fabric tube with a ring in one end to hold it open. Since the spinnaker is stored inside the dousing sock, it must first be rigged. Two lines are attached to the sock; one is attached to a bridle on the ring, for pulling the sock down, and one is up the inside, from the ring, through the top, and back down, for raising the sock; these lines may be two ends of the same line, to form a complete loop. The head of the spinnaker is attached the top of the dousing sock and the ring runs down to the tack. The resulting bundle is stuffed into the spinnaker bag. The top of the sock will have provisions for attaching to the spinnaker halyard. The spinnaker is raised as normal, but with the sock in place the spinnaker is unable to catch the wind. Once the spinnaker is raised and the guys are ready to set, the dousing sock is raised, releasing the spinnaker. The dousing sock remains bundled up at the head of the sail while the spinnaker is deployed. To retrieve the spinnaker, the sheet or the tack is released and the sock is pulled down, gathering the sail. The halyard is then dropped and the sail may be packed away.   Also called "Snuffer" or "Spinnaker Sleeve" or "Sock".

Downhaul - 1. the wire or rope tackle that pulls the foremost end of the boom on a sailboat down in order to tighten the luff of a sail 2. a line, attached to the tack of a sailboard, that adjusts tension in the luff of the sail. 3. to tighten the downhaul line. The opposite is to "ease" the downhaul.

Downwind or Down Wind - all points of sail and the all the area leeward of the centerline of a watercraft

Downwinder - a course that is to a destination downwind of its starting point

Drabbler - a piece of canvas fastened by lacing to the bonnet of a sail, to give it a greater depth, or more drop in light winds

Draft - 1. the depth of the curve of a sail   2. the vertical distance from the bottom of the keel to the waterline. (British - Draught)   Compare to Depth and Headroom   2. the depth or fullness of a sail

Drag - the resistance caused by wind and water

Drag Anchor - the breaking loose of an anchor, caused by high winds and seas, and dragging it freely across the bottom, thus putting the vessel to which it is attached, in peril

Draw - 1. a vessel is said to draw six feet of water if her draft is six feet deep   2. the sails are said to be drawing when they are filled with wind in order to give the vessel headway

Dressing Down - 1. treating old sails with oil or wax to renew them   2. a verbal reprimand

Drift - 1. the amount of movement of a boat caused by wind or air currents when not under power, or the amount of Leeway while under power. Compare to Pitch, Roll, Yaw, Surge, Leeway, Headway, Sternway, and Heave

Drift Lead - a lead placed on the bottom to indicate the movement of a vessel

Driver - the large sail flown from the mizzen gaff

Driver-mast - the fifth mast of a six-masted barquentine or gaff schooner. It is preceded by the jigger mast and followed by the spanker mast. The sixth mast of the only seven-masted vessel, the gaff schooner Thomas W. Lawson, was normally called the pusher-mast.

Drogue - a Sea Anchor

DRS - a sail known as a "Drifter/Reacher/Spinnaker

Drydock - a narrow basin or vessel that can be flooded to allow a load to be floated in, then drained to allow that load to come to rest on a dry platform. Drydocks are used for the construction, maintenance, and repair of ships, boats, and other watercraft.

Dryrot - decay of wood timbers caused by moist, but not necessarily wet, conditions

Dry Sailing - 1. keeping a boat out of the water when not sailing.   2. hoisting sail and drying the boat out after a sailing session

Dry Storage - storing on land, out of the water

Drysuit - a rubberized or impermeable neoprene, loosely fitting suit that allows insulation to be worn inside it, with neck, wrist, and ankle gaskets to keep out water, that retains the warmth of the sailor wearing it and, supposedly, keeps them dry.

Duck Jibe (Gybe) - changing the tack of a sailboard by grabbing the tail of the boom and letting the sail pass across the sailboard just before the board passes through straight downwind. The name derives from the improper assumption that the sailor "ducks under the sail." Instead, the mast is leaned forward, via the boom, in order for the sailor to avoid being hit by the boom or foot of the sail. This maneuver is easier, by far, than a regular jibe, but you need speed for stability as you enter the turn; this is why it is not taught to beginners.   See "Jibe"

Ducts - channels for the movement of fresh air or evacuation of fumes

Dutchman - a wooden plug used to fill a cavity in a hull member

Dutchman's Log - an early speed measuring device which uses a buoyant object tossed overboard near the bow of the vessel and assumed to be "Dead" in the water, or stationary, and the time it takes for the boat to move by it a certain, measured, distance on the deck is timed, then the speed of the vessel can be calculated. This does not take into account effects of wind and currents on the calculated position of the vessel.   Compare to Chip Log and Taffrail Log


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Earings or Earrings - small lines, by which the uppermost corners of the largest sails on a square rigged vessel are secured to the yardarms

Ease or Ease Off - to loosen or let out

Ebb - a tidal current flowing away from shore. Opposite of Flood.

Echo Sounding - measuring the depth of the water using a sonar device.   Compare to Sounding Line and Swinging the Lead

Eddy - a circular motion in the water caused by the meeting of opposing currents

Electrolysis - a term used loosely to describe electrochemical galvanic corrosive reaction between two different metals when they are placed in contact with one another

Electronic Navigation - sailing using automatic or manual electronic devices such as depth finders, electronic compass, radio direction finder, radar and various positioning systems like Loran, Decca, Omega, VHF Omnirange or GPS, etc., to navigate

El Niño - a warming of the ocean surface off the western coast of South America that occurs every 4 to 12 years when upwelling of cold, nutrient-rich water does not occur. It causes die-offs of plankton and fish and affects Pacific jet stream winds, altering storm tracks and creating unusual weather patterns in various parts of the world

Embayed - a condition where a sailing vessel is confined between two capes or headlands, typically where the wind is blowing directly onshore

Ensign - an organizational or national flag flown aboard a vessel

Entry - the design of the forward section of a vessel's hull in the water. This quantifies the type of hull in terms of efficiency and behavior in relation to wave action. For instance, a sharper bow means faster speeds for a racing hull.

Ephemeris - a catalogue of tables showing the location of various celestial bodies at specific moments in time throughout the year; consulted by the navigator in preparation for taking sights of celestial bodies. Such tables were known as "The Ephemeris" from the 18th C. until 1981 when it was jointly published by the US and Britian; now called the Nautical Almanac or Astronomical Almanac.

EPIRB - Emergency Position Indicating Radio Beacon - a small, continuously transmitting radio device on a standard distress frequency, used to alert authorities of a distress situation and lead rescue personnel to the scene.

Equator - an imaginary line on the Earth's surface equidistant from the North Pole and South Pole, dividing the Earth into the Northern Hemisphere and Southern Hemisphere and having a latitude of 0°. Certain navies, such as the U.S. Navy and the British Royal Navy, have a tradition of holding "line crossing" initiation ceremonies on board ship to mark sailors' FIRST crossing of the Equator, typically featuring King Neptune, Roman god of the sea, as do some civilian ocean liners and cruise ships.  See illustration at Prevailing Winds of the World

Estimated Position (EP) - a navigation point, less accurate than a fix, determined by course run, estimated speed, and estimated factors like drift caused by the wind and currents

ETA - an abbreviation for Estimated Time of Arrival

Even Keel - when a vessel is floating on its designed waterline or "Boot Top", it is said to be on an even keel

External Camber Inducer - a camber inducer that is in an opening in the mast sleeve of a sail board sail as opposed to inside the mast sleeve

Extremis (also known as "In Extremis") - the point under International Rules of the Road (Navigation Rules) at which the privileged (or stand-on) vessel on collision course with a burdened (or give-way) vessel determines it must maneuver to avoid a collision. Prior to extremis, the privileged vessel must maintain course and speed and the burdened vessel must maneuver to avoid collision.   See Right of Way

Eye Bolt - a bolt having a looped head mounted through the deck or stem on small vessels to receive a towing line or hook

Eye of the Wind - Directly upwind. In the direction from which the wind is blowing.

Eye Splice - a fixed loop in the end of a line made by doubling a line back on itself and either interweaving the strands back into the lay of the rope, or tucking the end of a double-braided line back into the core.   See Knot on this page


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Fair - 1. A smooth curve, usually referring to a line of the hull which has no deviations   2. In lofting, to correct a hull's lines with the use of a batten; making them even and regular   3. To make something flush   4. A rope is fair when it has a clear run   5. A wind or current is fair when it offers an advantage to a boat. (Opposite of Foul)

Fairlead - an eye or block used to change the direction of a line without chafing and/or to give the line a better angle to a winch. Often used on modern boats to guide the jib sheets.

Fake or Fake Down- to lay a rope in a series of flat, elongated, side-by-side coils. To fake down a rope, a short length of the working or free end of the line is laid out in a straight line on the deck and then turned back on itself to form a small coil. The line is then laid back along itself beyond the free end and another coil made at a short distance. Successive coils or Flakes are made, laying the coils neatly upon each other at the end of each straight section, keeping the straight portions uncrossed and flat.   Compare to Flemish Flake and Coil Down

Fall - 1. the rope or chain of a block and tackle; especially the end to which the power is applied in hoisting. Also called Hauling Part.   2. a wide front flap on trousers (as those worn by sailors)

Fall Off - a vessel is said to "fall off" when its bow turns away from the direction from which the wind is coming

False Stem - a separate timber that attaches to the stem, covering the side planking. Also called the Cutwater

Fast - Tied or held firmly (made fast: tied securely; fast aground: stuck on the seabed)

Fathom - a measurement relating to the depth of water, one fathom is 6 feet or 1.83 meters

Fathometer - a trademarked name for a brand of sonar depth finder

FCC or Federal Communications Commission - the ruling agency in the U.S. for radio equipment and its operation

Feather - 1. to turn the blade of an oar, after the power stroke, so that it rests or moves parallel to the waters surface on the return stroke, in order to decrease resistance to wind and waves.   2. to change the course of a sailboat slightly to windward upon being hit by a puff of wind in order to reduce the force of the wind on the sails and avoid excess healing. A stronger gust might require a full-fledged luffing of the sails.

Fender - a cushion made of rope, rubber, or inflatable plastic hung over the sides to keep boats from banging into docks or each other when docking or berthed. Don't call them "Bumpers" unless you want to get laughed at.

Fend Off - to hold away from

Fetch - 1. the distance over which wind blows across the water's surface   2. In some countries, "Fetch" or "Fetching" is the same as being on a close reach

Fiberglass - 1. strands, matte, or woven glass fibers   2. stranded, matte, or woven glass fibers laid up on a form and reinforced with an epoxy or polyester resin   GRP - Glass Reinforced Plastic

Fid - a tapered, sometimes hollow, rod, made of wood, bone, or plastic, used to open the "lays", or strands of synthetic or natural rope for splicing.   Compare to Marlinspike

Fiddle - a small rail on tables and counters used to keep objects from sliding off when heeled or in heavy seas

Fiddle Block - See Block

Fife Rail - a rail around the mast with holes for belaying pins

Figure-Eight Knot - a very good stopper knot, used to keep a line from passing through a block or fairlead. Use a figure-eight knot instead of an overhand knot whenever you can; although it will pull down tight, it is significantlyl easier to untie than an overhand knot. One of the eight knots everyone should know. See at Knot on this page

Figurehead - a symbolic, carved image at the head, mounted under the bowsprit, of a traditional sailing ship or early steamer

Fin - skeg, a blade on the bottom rear of a sailboard that creates lift and gives the board the ability to hold a straight course by reducing side slippage.

Fin Box - the slot built into the bottom rear of a sailboard for the fin or skeg to fit into and lock in place. There are several variations, each with its corresponding set of fins. Fins are not interchangeable between models of finboxes.

Fin Keel - a longitudinally short, but deep, keel on a vessel   Compare to Full Length Keel on this page

Finger Pier - a long narrow pier projecting from shore or projecting at right angles from another pier

Fireboat - a boat equipped with water pumps and water cannons to fight fires along waterfronts and on ships

Fireship - a ship loaded with flammable materials and explosives and sailed into an enemy port or fleet either already burning or ready to be set alight by its crew (who would then abandon it) in order to collide with and set fire to enemy ships

First Mate - The Second in command of a ship

First Rate - The classification for the largest sailing warships of the 17th through 19th centuries. They had 3 masts, 850+ crew and 100+ guns

Fish - 1. To repair a mast or spar with a fillet of wood.   2. To secure an anchor on the side of the ship in preparation for getting under way after Catting, or lifting the anchor to the Cathead

Fisherman's Anchor - an older (1840's), but very good anchor design that features long iron arms with a long stock set perpendicular to the arms and at the top end of the shank. No longer used for large ships but continues in use for small boats and for moorings. Although it has great holding power in a penetrable bottom it is extremely awkward and the long stock is vulnerable to mechanical damage. When in position the upstanding arm may foul a chain or pierce the hull of a vessel. Also called an Admiralty Anchor. See the illustration at Anchor

Fisherman's Staysail - a full, quadrilateral sail used in light air on schooners. It is flown high, between the fore and main mast, and is also known as a Gollywobbler   See Sails

Fishhook - 1. a sharply pointed hook, usually baited, for catching fish.   2. the sharp, broken individual wire strands in a wire rope or cable; so named because of the ferocity with which they rip or puncture skin. If a line has more than a very few fishhooks, it should be replaced. Also called "Meathooks".

Fix - an accurate determination of your position without reference to a previous position. Compare to Dead Reckoning

Flag Semaphore - See Semaphore Flags

Flake - 1. one complete coil of a line that has been Faked Down   2. to fold the sails in place on the deck

Fake To - to lay a rope or chain up and down on the deck so the whole length is exposed

Flank Speed or Flanking Speed - the maximum speed of a ship; faster than "full speed"

Flam - that part of the topsides that flares just below the foredeck

Flame Arrestor - a safety device like a metal mesh on an engine's air intake that absorbs heat and keeps a backfire from causing an explosion if gas vapors are present

Flare - 1. upward curve and outward spread of the topsides at the top of the bow in order to make the bow more buoyant and to keep the deck dry by deflecting waves away from the vessel.   2. a pyrotechnic signaling device, usually used to indicate distress

Flashing Light - a signal lamp that is on more than it is off in a regular sequence of single bursts not greater than 30 times per minute

Flash-Lock - a lock that, after being partially emptied, is opened suddenly to send a boat over a shallow place with a rush of water. Also called, staunch or stanch, or navigation weir.

Flat (also called Platform) - a partial, non-structural, horizontal surface between two full decks or on top of one. Compare to Deck

Fled Block - that part of a block and tackle system which is attached to the permanent support. Also called the "standing block."

Flemish Flake - a coiled a rope on the deck in a flat, one layered, tight spiral starting with the working or free end in the center. This ends up looking like a mat and is very unlikely to tangle or be tripped over.   Compare to Fake Down and Coil Down

Flip the Sail - to rotate the rig so that the clew passes around the mast toward the bow of the sailboard in order to fill the sail with wind from the other side.

Flinders Bar - a soft iron bar, in or on the binnacle, in place to compensate for compass error from vertical magnetism in a vessel with an iron hull

Floe - Sea ice. Either a single piece or serveral/many pieces floating as a group

Flog - the violent back and forth whipping of a sail whose clew has been release in strong winds

Flood - a tidal current flowing toward shore. Opposite of Ebb

Floors - transverse members that reinforce the frames and carry the strength athwartships across the keel

Floorboards - the surface of the cockpit on which the crew stands

Floor Timbers - athwartships timbers that attach to keel and frame heels and serve to unify the backbone and framing as well as strengthen the lowermost strakes

Flotation - a measurement of buoyancy for sailboards. The number of liters that a sailboard displaces when submerged. The larger the number of liters, the more flotation and the greater weight of sailor and rig it will carry

Flotsam - Debris or cargo that remains afloat after a shipwreck.   Compare to Jetsam and Lagan or Ligan and Derelict and Marine Debris

Fluke - the wedge-shaped part of an anchor's arms that digs into the bottom

Flush Deck - a deck with no superstructure or upward protruding cabin

Flying - a term describing a sail not bent to any spar or stay and controlled by its halyard, tackline and sheet

Fly By Night - a large sail used only for sailing downwind, requiring little attention

Flying Bridge - a secondary set of controls on larger vessels, higher, for better visibility

Following Sea - waves or tidal movement directly to aft of and going in the same direction as a vessel

Foot - 1. the bottom edge of a sail   2. the bottom of a mast   3. a measurement of 12 inches   4. when sailing upwind, to ease the sails slightly and sail faster instead of trying to point

Footlings - bottom boards or walking flats attached to the insides of the frames on boats where deep floors are not fitted

Footloose - If the foot of a sail is not secured, it is footloose.

Footrope - 1. a rope on each yard on a square rigged sailing ship for sailors to stand on while setting or stowing the sails (Also, in antiquity, called a "Horse")   2. the boltrope along the foot (bottom) of a sail

Footstraps - 1. straps attached to the deck of a sailboard that fit snugly over the front of the foot of the sailboarder in order to enhance the control of the board with the feet or to keep the sailboard from falling away from the feet during a jump. 2. a horizontal strap running fore-and-aft in the cockpit, on deck, or on the trampoline of a small vessel for the crew to hook their feet under when leaning out over the side of the vessel (hiking out), in order to keep from falling overboard, while counteracting the lateral force of the wind on the sails that is trying to rotate the vessel around its longitudinal axis (tip the boat over) Hiking straps.

Fore-and-Aft - a reference or parallel relationship to the longitudinal axis or centerline of a vessel

Fore & Aft Rigged Sails - sails suspended directly from the masts or gaffs and attached to booms, such that the sails, when sheeted in, run approximately parallel to the centerline of the ship, unlike Square Rigged Sails that run at approximately 90 degrees to the centerline. See the photographs at the top of this page.   Compare to Square Rigged Sails

Forecastle (Pronounced "foc'sle") - a partial deck, above the upper deck and at the head of the vessel; traditionally the sailors' living quarters. The name is derived from the castle fitted to bear archers in time of war.

Foredeck - the forward portion of the main deck of a vessel

Forefoot - the forward part of the keel that adjoins the stem

Foreguy - a line used to control the spinnaker pole and keep it from getting too high

Foremast - the forward mast of a boat that has more that one mast

Forepeak - a compartment or area inside the bow on smaller vessels. It often contain the chain locker or other storage.

Foresail - any sail before the mast; any jib, genoa, gennaker, spinnaker, etc.

Foresheets - the portion of the boat forward of the foremast thwart

Forestay - lines or cables reaching from the front portion of the deck, between the bow and mast to near, but below the masthead, sometimes used to support the mast on a fractional rig.   Compare to Headstay, Jibstay, and Backstay

Foretriangle - the triangular area formed by the mast, deck and bowsprit, and forestay. If a foresail is equal to or smaller than the foretriangle, it is a jib; if it is larger, it is a genoa, gennaker, or spinnaker.

Formula Class sailboard - Shorter boards up to one meter in width, for use in Formula Windsurfing races. These boards are designed primarily for sailing up and downwind rather than on a beam reach.

Forward - toward the bow to the boat   See General Shipboard Directions illustration.

Foul - 1. a piece of equipment that is jammed or tangled. For example, a rope is foul when it does not run straight or smoothly, and an anchor is foul when it is caught on an obstruction or its own rode. The opposite of clear or fair.  2. A breach of racing rules

Foul an Anchor - to hook another anchor, wreck, or cable, under the surface of the water; or when, by the wind suddenly abating, the ship slackens her strain, and straying round the bed of her anchor entangles her slack cable about the upper fluke of it, and easily draws it out of it's place as soon as she begins to ride with a strain. To prevent this, it is usual, as a vessel approaches the anchor in light winds, to draw the slack cable into the ship.

Founder - to fill with water and sink

Fractional Rig - a fore-and-aft sail configuration, typically used on dinghy sailing boats and racing oriented keel boats, consisting of a foresail, such as a jib or genoa sail, that does not reach all the way to the top of the mast.   See two sailboats photograph at the top of the page for a comparison.

Frames - 1. the principal structural members, comprising the skeleton of a hull.   2. a transverse structural member which gives the hull strength and shape. Wooden frames may be sawn, bent or laminated into shape. Planking is then fastened to the frames. A bent frame is called a timber. Also called Ribs

Free (Sailing Free) - sailing any point of sail except close hauled

Freeboard - the distance from the gunwale to the waterline

Freeride Sailboard - meant for comfortable recreational cruising (mostly straight-line sailing and occasional turning) at planing speed, mainly in flat waters, light chop, or in light to moderate swell. They typically fall into the volume range of 90 to 170 liters

Freestyle Sailboard - Related to wave boards in terms of maneuverability, these are wider, higher volume boards geared specifically at performing acrobatic tricks (jumps, rotations, slides, flips and loops) on flat water. Usually 80 to 110 liters in volume, and about 240 to 250 centimeters in length, with widths frequently in excess of 60 centimeters. Freestyle boards began to diverge more noticeably in design from wave boards in the early part of the year 2000 decade, as aerial tricks (the Vulcan, Spock, Grubby, Flaka, and related New School maneuvers, almost all involving a jump-and-spin component) became the predominant part of the freestyle repertoire, superseding Old School moves, in which the board did not leave contact with the water.

Frigate - a warship. In the age of sail, a Frigate was usually a long, low, fast, light weight, full-rigged ship, built to fight, patrol, and escort other ships. Frigates have changed significantly over the centuries and many nations still have frigates in their navies; although they now are all steel and armed with missiles.   Compare to other sailboat types on this page.   For more information, see Frigate at Wikipedia.

Full and By - Sailing into the wind (by), but not as close-hauled as might be possible, so as to make sure the sails are kept full. This provides a margin for error to avoid being taken aback (a serious risk for square-rigged vessels) in a tricky sea. Figuratively it implies getting on with the job but in a steady, relaxed way, without undue urgency or strain.

Full Length Keel - a longitudinally long, but shallow, keel on a vessel.   Compare to Fin Keel on this page

Full Rigged Ship or Fully Rigged Ship or Ship - a sailing vessel with three or more masts, all of them square rigged. A full rigged ship is said to have a ship rig.

Fully Battened Sail - a sail that has battens (stiffeners) that run horizontally clear from the leech to the luff

Furious Fifties - the name given to strong westerly winds found in the Southern Hemisphere generally between the latitudes of 50 and 60 degrees. Air displaced from the Equator towards the South Pole, which travels close to the surface combines with the earth's rotation to cause west-to-east air currents. Because there is little land below the 40th parallel south, greater wind speeds are able to build than in the same region of the Northern Hemisphere that contains significant land masses.   See illustration at Prevailing Winds of the World
      Similar conditions occur in adjacent latitudes, and are referred to as the Roaring Forties, that are usually weaker, and the Screaming Sixties that are usually more extreme.

Furl - to fold or roll a sail and secure it to its main support

Futtocks - pieces of timber that make up a large transverse frame


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Gaff - 1. the spar that is attached to the upper edge of a fore-and-aft mounted sail, if so rigged   Compare to Sprit and Yard   2. a long hook with a sharp point to haul fish aboard

Gaff Rigged - 1. a fore-and-aft sail mounted on an upper spar or gaff which extends aft from the mast.   2. a vessel thus rigged.   Compare to Lugsail or Spritsail

Gale - a strong wind. Actually, there are four categories of Gale: Moderate, Fresh, Strong, and Whole Gale Storm from Beaufort number  7 - 10 respectively.

Galleon - a large, multi-decked, square rigged vessel of the 16th to 18th centuries with 3 to 5 masts with a lateen sail on the mizzenmast. The principal warships of the opposing English and Spanish fleets in the 1588 confrontation of the Spanish Armada were galleons and were the prototype for all three or more masted, square rigged ships for over two and a half centuries, including the coming full rigged ship.   Compare to other Types of Sailboats on this page

Galley - 1. a kitchen onboard a ship or boat.   2. a vessel whose main propulsion was rowing, but had some square sails. It was in use from 3000 years ago until the 1700's. Some had as many as three levels of rowers and in excess of 300 rowers, almost always, slaves.   Compare to other Types of Sailboats on this page

Gallows - a frame used to rest the boom on when the sail is furled

Gammon Iron - the bow fitting which clamps the bowsprit to the stem

Gangplank - a movable bridge or walkway from ship to shore used in boarding and leaving a ship

Gangway - an opening in the Bulwark of a ship to allow boarding and disembarking of passengers

Garboard Planks - the first planks immediately on either side of the keel

Gantline - a rope rove through a single block hung from a mast, funnel, etc., as a means of hoisting workers, tools, flags, or the like.   Also called Girtline

Gasket - a light line for securing a furled sail to a boom; a sail stop

Gate - a hinged, semicircular, metal band attached to a thwart on a small sailing vessel to help stay a mast

Gel Coat or Gelcoat - the standard outer, visible finish on a fiberglass hull. Gelcoats are designed to be durable, providing resistance to ultraviolet degradation and hydrolysis. The gelcoat will often carry a pigment that provides the finish color to the hull.

Gennaker - a foresail larger than either a jib or a genoa, with much greater camber for generating larger amounts of lift when reaching. spinnakers are used when running, instead of gennakers or genoas, because when running, the mainsail blocks the wind of a gennaker or genoa.

Genoa - a large foresail that reaches aft past the mast and overlaps the mainsail

Ghost - to sail along very slowly when there appears to be no wind

Gibe - a change of tack going downwind that brings the stern through the eye of the wind.     See Jibe

Gibson Girl - a portable radio transmitter used in lifeboats

Gig - 1. a light boat rowed with four, six, or eight long oars.   2. a boat reserved for the use of the captain of a ship.

Gimball - a pivoted device that suspends a compass, stove or other devise so that it remains level when its support is tilted

Girtline - a rope rove through a single block hung from a mast, funnel, etc., as a means of hoisting workers, tools, flags, or the like.   Also called Gantline

Give Way - to yield right of way

Give-Way Vessel - "Burdened Vessel" - the vessel that must yield to the "Privileged Vessel" in a Right of Way situation

Global Positioning System - a world-wide, satellite based locating system capable of fixing a position with extreme accuracy

GMT - Greenwich Meridian Time, also known as Universal Time or Zula Time

Go About - to tack a vessel; to change course by turning the bow into the wind so that the wind comes from the other side of the boat - to come about

Gob - an ordinary enlisted seaman in the US Navy; a sailor

Gollywobbler - a full, quadrilateral sail used in light air on schooners. It is flown high, between the fore and main mast, and is also known as a fisherman's staysail   See Sails

Gooseneck - a swiveling device that connects the boom to the mast of a sailboat or ship, allowing the boom to swivel vertically and horizontally. Also called the Pacific Iron   Compare to Jaws   See "Boom Head" for sailboarding

GPS - Global Positioning System - a world-wide, satellite based locating system capable of fixing a position with extreme accuracy

Goosewinged - to sail wing-on-wing with the headsail on the windward side

Granny Knot - the False Reef Knot. a poor knot often confused for the Square Knot. It slips easily and is often hard to untie when pulled down hard.

Grab Rails - hand holds on the cabin sides and top for personal safety when moving around the boat

Grapeshot - Grapeshot is a type of anti-personnel ammunition fired from a cannon for the purpose of causing bodily harm to the enemy rather than do structural damage to his ship. Instead of solid shot (cannon balls), a mass of loosely packed metal slugs, or chain links, shards of glass, rocks, etc., in a bag was loaded. When assembled, the balls resemble a cluster of grapes (hence the name). On firing, the bag disintegrates and the balls spread out from the muzzle at high velocity, giving an effect similar to a shotgun, but scaled up to cannon size. Grapeshot was largely replaced by canister shot during the early 19th century, with the cloth bag being replaced with a wood-sealed metal canister.   Compare to Chain Shot, Cannon Balls, and Canister Shot

Grapnel - lightweight anchor with claw-like hooks or barbs used as an anchor or in dragging, grappling or boarding operations

Grave - to clean a ship's bottom

Great Circle - the intersection of a sphere and a plane that passes through its center. This is the shortest distance between two points on the surface of the sphere.

Greater Ebb - the stronger of two ebb currents that occur in one day

Greater Flood - the stronger of two flood currents that occur in one day

Greenwich Mean Time - the local time at the Greenwich Meridian, also known as Universal Time or Zula Time

Greenwich Meridian - the meridian passing through Greenwich, England and serving as the prime meridian and as the reference meridian for Greenwich Time

Gripe - a curved timber used to join the keel to the stern

Grog - watered-down pusser's rum consisting of half a gill with equal part of water, issued to all seamen over twenty. From the British Admiral Vernon who, in 1740, ordered the men's ration of rum to be watered down. He was called "Old Grogram" because he often wore a grogram coat), and the watered rum came to be called 'grog'. Often used (illegally) as currency in exchange for favors in quantities prescribed as 'sippers' and 'gulpers'. Additional issues of grog were made on the command 'splice the mainbrace' for celebrations or as a reward for performing especially onerous duties. The RN discontinued the practice of issuing rum in 1970. A sailor might repay a colleague for a favor by giving him part or all of his grog ration, ranging from "sippers" (a small amount) via "gulpers" (a larger quantity) to "grounders" (the entire tot).

Groggy - drunk from having consumed too much grog

Grommet - a metal ring fastened in a sail or tarpaulin through which lacing or robands may pass

Ground - the bed of the sea, lake or river

Grounding - when a ship (while afloat) touches the bed of the sea, or goes "aground"

Ground Swell - a long ocean wave or series of waves that started a considerable distance away and are increasing in height and getting shorter in length because of the gradient of the bottom as they arrive in shallower waters

Ground Tackle - the anchor, chain and rode

Growler - a small iceberg, piece of an iceberg, or other sea ice that is large enough to be a hazard to shipping, but small enough to avoid detection

Gudgeons - small metal fittings, similar to eyebolts, secured to the sternpost on very small boats, through which the pintles fit, in order to attach the rudder to the stern of the boat

Gun Deck - any deck with guns; on most of the old sailing ships it was a enclosed deck below the main deck. First Rate Ships had three gun decks.

Gunkholing - cruising in shoal water or overnighting in small coves

Gunter Rig - a triangular sail hung from a yard that slides up a shortened mast and raises to vertical, allowing the peak of the sail to be much higher than the mast. This is similar to a Gaff Rig, but the yard raises all the way to vertical. This rig is very convenient on small boats because it allows the whole rig to be unstepped at the mast and laid down in the boat for storage. Once the sail is raised, it looks and performs much like the triangular Marconi Rig. If using a boom, it is, however, rather difficult to reef the sail.   Compare to other Rigs

Gunwale (Pronounced "Gun'l") - the upper edge of the sheer strake or hull of the boat at deck level

Guy - a controling line attached to the end of a movable spar; specifically, the inboard or windward controlling line, attached to the tack of a spinnaker; the outboard line is the sheet and is attached to the clew. The Guy always goes through the outboard end of the spinnaker pole

Guy Hook - a metal hook near the shrouds used to hold the guy near the deck

Gybe, Gibe or Jibe - a change of tack going downwind that brings the stern through the wind's eye. Compare Gybe to Wearing.     See Types of Sailboard Gybes

Gybe Ho - a notification or warning that a gybe (jibe) has been initiated by the helmsman. Watch out for the Boom!!!


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Hail - to call a vessel

Half-Breadth View - in a lines plan, the view of the half of the hull from above. Since a hull is longitudinally symetrical, only half of the hull is drawn.

Halyard - the lines used to raise and lower the sails

Halyard Rack - a toothed rack on which the halyard may be tensioned to adjust the luff of the sail

Handy Billy - a loose block and tackle with a hook or tail on each end, which can be used wherever it is needed. Usually made up of one single and one double block.   See Block

Handycap - a type of racing among dissimilar boats where finish placement is determined by finishing position and the boat's measured ratings

Hand Lead - a weight on a line lowered into the water to measure the depth

Hand Over Fist (originally "hand over hand") - to climb steadily upwards (from sailors climbing shrouds on a sailing ship)

Handsomely - slowly and carefully; as, "to ease a line handsomely"

Hanging Knee - a wooden brace that attaches to the hull's side and supports the deck beams or decking

Hanging Locker - a storage place for clothing that is hung on clothes hangers or hooks

Hank - A fastener attached to the luff of a headsail that attaches the headsail to the headstay or forestay. Typical modern designs include a bronze or plastic hook with a spring-operated gate, or a strip of webbing with a snap fastener

Harbor or Harbour - a place where ships may shelter from the weather or are stored. Harbors may be man-made or natural

Harbor Chart - small nautical charts designed for navigation in harbors and small waterways

Harbor Master - a person in charge of docking spaces, anchorages, refuse collection, etc., in a harbor

Hard Alee - the command given to inform the crew that the helm is being turned quickly to leeward, turning the boat windward in order to tack. Watch out for the boom!!!   Also "Helm's Alee"

Hard-Chined - a hull shaped with flat sides joined at an angle

Harden Up - to steer closer into the wind, usually by tightening the sheets

Hard Over - as far as possible in one direction, for instance, a wheel or tiller can be "Hard Over" to make an abrupt turn

Hard Tack or Hardtack - a simple type of cracker or biscuit, made from flour, water, and sometimes salt. Inexpensive and long-lasting, it was and is still used for sustenance in the absence of perishable foods, commonly during long sea voyages and military campaigns. The name derives from the British sailor slang for food, "tack". It is also known by other names such as pilot bread (as rations for ship's pilots), ship's biscuit, shipbiscuit, sea biscuit, or sea bread.

Hatch - a covering for a Hatchway

Hatchway - a covered opening in a ship's deck through which people can access lower decks or cargo can be moved. The cover for a hatchway is a Hatch

Haul - 1. to pull on; as to "haul on a line". 2. Said of the wind; to change direction as, "the wind hauled occasionally to the southward."

Haul Around - to change from a run to a reach

Hauled Flat - the condition of the sails when they are running almost directly fore-and-aft, but still drawing wind

Hauling Part - the working end of tackle (rope or chain) attached to a block that is pulled on in order to move the load (Also called Fall)   See Block

Haul Out - to remove from the water

Hawse-hole or Hawse-pipe - a hole in a ship's bow for a cable or chain, such as for an anchor or mooring line, to pass through

Hawser - a large rope or cable used for mooring or towing a vessel

Head - 1. top corner of a triangular sail & the top edge of a square sail   2. the front of the ship includind the bow and adjacent areas   3. the toilet or latrine on board a vessel. (On older sailing ships this was at the Bow of the ship, out over the water)

Header - a shift in wind direction closer to the bow of the vessel causing you to head off in order to keep your sails from luffing.   Opposite of a Lift.

Headfoil - a metal extrusion fitted on a forestay and used to secure the luff of a sail by holding the bolt rope in place

Heading - the direction in which the bow of the vessel is pointed, expressed as an angular degree from 0° at North, clockwise through 360°. Not to be confused with Course. Heading is a constantly changing value as the vessel oscillates or yaws back and forth across the course or temporarily changes direction as in avoiding an obstacle. Course is a predetermined direction that remains the same for a considerable time.   Compare to Course, Course Made Good, and Track

Head Ledges - vertical timbers at either end of a centerboard trunk or case that attaches to and stabilizes the planks of the trunk

Heads Up! - a warning to watch out; meaning that in reality, you'd better duck your head!

Head of Navigation - a term used to describe the farthest point above the mouth of a river that can be navigated by ships

Head-Off - to turn downwind of your current course. Fall off.

Headroom - the vertical space between floors or deck on which you are standing and the top of the cabin, canopy top or other overhead structure you are in; whichever applies   Compare to Depth and Draft

Headsail - a sail forward of the most forward mast, a foresail

Head Seas - waves coming from the direction to which you are sailing

Headstay - a support line attached to the masthead and running to the bow or bowsprit. The luff of the jib may be attached to the headstay with hanks.   Compare to Forestay, Jibstay, and Backstay

Head to Wind - the bow turned into the wind, sails luffing

Head Up - to turn upwind of your current course. Opposite of "Bearing Away", "Bearing Off", or "Falling Off"

Headway - forward motion of a vessel. Compare to Sternway, Pitch, Roll, Yaw, Leeway, Drift, Surge, and Heave

Headwind - a wind that you are trying to sail toward. Opposite of Tailwind.

Heave - 1. the non-rotational movement of a vessel up and down. Compare to Pitch, Roll, Yaw, Leeway, Drift, Surge, Sternway, and Headway   2. to throw, as a line   3. to pull on, as a line

Heave Down - Turn a ship on its side (for cleaning). To Careen

Heave To - to stop a boat and maintain position (with some slight leeway) by balancing rudder and sail in opposition to each other to prevent forward movement, a boat stopped this way is "hove to"

Heaving Line - a light line, thrown from ship to ship or ship to shore in order to pull a larger line, such as a hawser. See Messenger

Heavy Airs - wind that moves at over 24 mph (20 Knots) (36 kph). Good winds to use a Storm Jib on a knockabout or sloop. Winds at this speed are usually called High Winds by sailboarders and are for advanced sailboarders only.   See Airs

Heavy Weather - Stormy, windy weather accompanied by rough or high seas, discomfort and, perhaps, danger!

Heel - the leeward lean of a sailboat caused by the wind's force on the sails

Heeling Error - additional and temporary compass deviation cause by iron (engine, keel, etc.) in the vessel shifting position relative to the compass as the vessel heels

Helm - the tiller or wheel, and surrounding area

Helm's-A-Lee - a notification or warning that the tiller has been moved toward the lee side of the vessel by the helmsman in order to turn the vessel upwind to tack (come about). Watch out for the boom!!!   Also "Hard Alee"

Helmsman - the member of the crew responsible for steering

Hemp - one of the oldest (thousands of years) natural fibers (the marijuana plant) that ropes can be made of similar to, but pretty well replaced by manila in natural fiber ropes. Hemp is a tall plant that has useful fibers for making rope and cloth. It was used extensively before manila was introduced. Now hemp's principal use is in fittings such as ratline and marline. Because hemp is absorbent, the fittings are tarred to make them more water-resistant.   See Line

Hermaphrodite Brig - See at Types of Sailboats on this page

Higher High Water or Tide - the higher of two high tides occurring during a tidal day

Higher Low Water or Tide - the higher of two low tides occurring during a tidal day

Highfield Lever - A particular type of tensioning lever, usually for running backstays. Their use allows the leeward backstay to be completely slackened so that the boom can be let all the way out

High Tide - the maximum height reached by a rising tide

High Water Inequality - the difference between the heights of the two high tides of a tidal day

High Wind - air that moves at over 24 mph (20 Knots) (36 kph), and is usually sailed by advanced sailboarders.   See Heavy Airs

Hike - leaning out over the side of the boat to counteract the force of the wind trying to blow it over

Hiking Board - a board temporarily extended out over the side of the gunwale of a boat to sit on while hiking out. Compare to Trapeze

Hiking Out - See "Hike"

Hiking Stick - an extension for the tiller that lets the skipper control the tiller from the high side of the boat or while hiking out

Hiking Straps - straps to hook your feet under to keep from falling overboard while hiking out

Hitch - 1. to tie a line to an object. 2. a knot used to tie a line to an object. Many hitches will fall apart (capsize) if removed from the supporting object. Compare to Bend   3. An attachment, usually at the rear of a vehicle, that allows a trailer to be attached to the vehicle for towing.

Hitch Ball - a portion of a trailer hitch in the form of a sphere on a post that the coupler of the trailer fits over and locks onto

Hoist - to raise aloft

Hogging - a condition occurring when the middle of a vessel is supported more by waves than the ends causing the keel to flex and the ends to be LOWER than the midships. Opposite of Sagging.

Hogging Piece - in small boats, a timber attached on top of the keel to provide a surface to which the garboard strakes may be fastened. Also called a Keel Batten.

Hold - the portion, below decks, that is used for storage of cargo

Holding Tank - a storage tank for sewage so that it isn't pumped or dumped into the water

Holystone - a bible shaped sandstone rock used, along with sand, to scrub decks. Also called a "bible" because it brought sailors to their knees

Homing - sailing directly toward a radio beacon or other transmitter using a radio direction finder to "home in" on it

Hood Ends - plank ends at the bow and stern

Hook - an anchor

Hop - travel of a radio wave from the origin to the ionosphere and back to earth

Horizontal Angle - an angle, usually measured by a sextant, between two landmarks, providing a line of position (the arc of a circle)

Horn Timber - a fore-and-aft structural member of the hull sloping up and backwards from the keel to the transom to support the overhang of the counter. Also called the Counter Timber

Horse - 1. the horizontal bar or rail that the traveler slides sideways on   2. to caulk a wooden vessel with a hammer or loggerhead   3. (Antiquated) a footrope to stand on while furling/unfurling sails on a square rigged vessel

Horse Latitudes - the latitudes near 30° N or 30° S at sea, characterized by inconsistant and changeable winds, calms, and high barometric pressure.   See illustration at Prevailing Winds of the World

Horseshoe Buoy - a U-shaped personal flotation device (PFD), mounted on a ship's railing, used in rescues and man overboard situations

Hounds - Hardware that attaches the upper ends of shrouds and stays to masts

Hourglass - a fouled spinnaker whose middle is twisted so that only the top and bottom of the sail fill, but the wind spills without significant force being applied to the sail

Hull - the hollow, lowermost outer skin of a ship, floating partially submerged and supporting the remainder of the ship

Hull Down - sufficiently far away that, because of the curvature of the sea's surface, the hull of a distant vessel cannot be seen below the horizon, only its sails or superstructure. Since a person standing at sea level can see approximately 7 miles on a clear day, this gives an idea of how far away a vessel is. If only the sails can be seen, and not the hull, it must be at least 7 miles away. Of course, if you are observing from the crow's nest, it is still further yet.

Hull Speed - the absolute maximum, theoretical speed at which a boat will travel. Hull speed (for a displacement hull) is a mathematical formula based on the length of the waterline. Hull Speed (in knots) = 1.34 times the square root of the waterline in feet. 1 mph = roughly 0.869 knots. Of course, many other factors, including, but not limited to, wind speed, sail area, point of sail, sail trim, smoothness of the hull, ability of the sailors, etc., work to keep the vessel below hull speed.   By the way, it is incorrect to say, "What is your maximum hull speed?", because that would be redundant, asking "What is the maximum maximum speed of your boat."

Hull Worms - See Teredo Worm

Hurricane - A severe, rotating tropical cyclone originating in the equatorial regions of the Atlantic Ocean or Caribbean Sea or eastern regions of the Pacific Ocean, traveling north, northwest, or northeast from its point of origin, and usually involving heavy rains and wind with a speed greater than 74 miles (119 kilometers) per hour, according to the Beaufort scale. Called "Typhoon" in other parts of the world.   Also see Saffir-Simpson Hurricane Scale

Hurricane Hole - A harbor used to provide shelter from a storm. Ideally, a small, natural bay with a small opening to protect from waves and high sides to protect from the wind - also called an Asylum Harbor.

Hydrofoil - A boat with wing-like foils mounted on struts below the hull that lift the boat out of the water at planing speed

Hydrography - the science of surveying the surface waters of the earth with special reference to their use in navigation

Hydrolant - an urgent notice of dangers to navigation in the Atlantic Ocean

Hydropac - an urgent notice of dangers to navigation in the Pacific Ocean

Hygrometer - an instrument for measuring the humidity in the air

Hyperpyrexia - heat stress, caused by high temperature, humidity, exercise, and exposure to the sun

Hypothermia - a dangerous decrease in body temperature due to exposure to cold water, low air temperatures, and/or a high wind chill factor that will greatly reduce strength, decision making abilities, and ability to survive

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Ice Anchor - an anchor used for securing a vessel to ice

Iceberg - a mass of land ice that has broken away from its parent formation on the coast and either floats in the sea or is grounded

Ice Boat - a T-shaped frame on three runners powered by fore-and -aft sails. Very fast, sometimes reaching well over 100mph

Ice Field - Sea ice covering an area greater than five miles across

Ice Shelf - a thick ice formation with level surface extending over the sea but attached to the land

Icing - a serious hazard where cold temperatures (below about -10° C) combined with high wind speed (typically force 8 or above on the Beaufort scale) result in spray blown off the sea freezing immediately on contact with the ship. The added weight above decks and its inherent high center of gravity can cause a vessel to capsize.

Idlers - members of a ship's company not required to serve watches. These were in general specialist tradesmen such as the carpenter and the sailmaker.

Indexed Mast Check System (IMCS) - an internationally recognized method of calibrating the stiffness and curve characteristics of sailboarding masts, based around the standard length 465cm mast. Sail manufacturers will provide a recommended IMCS number which lets you know exactly what stiffness and curve of mast best suits a particular sail.

Inboard - 1. inward, closer to the centerline of the vessel     See General Shipboard Directions illustration.2. the use of outboard and inboard varies when a vessel is moored to a pier. The side against the pier is inboard; the side away from the pier is outboard.   3. an engine permanently mounted within the hull and whose only parts outside the hull are part of the drive shaft and propeller

Inboard/Outboard (I/O) - a propulsion system that uses an inboard motor, mounted at the transom, with a propeller assembly, similar to the bottom of an outboard, mounted on the outside of the transom, bolting to the motor with the transom sandwiched between

Inflatable Boat - a craft that has an inflatable hull and pontoons, or, perhaps, a flat, rubber hull with floorboards and pontoons for the above water hull; frequently used as tenders for larger vessels.   Compare to RIB on this page

Inglefield clip - a type of clip for attaching a flag to a flag halyard

Inhaul - a line passing through the boom head that allows the boom to be attached tightly to the mast of a sailboard

In Irons - 1. having turned into the wind or lost the wind, stuck and unable to make headway, and, for lack of momentum and/or steerage, unable to turn off the wind.   Compare to In Stays, Miss Stays and Refuses Stays.   See "Points of Sail"

In Stays - the temporary situation of a vessel that has enough momentum to complete the turn, when she is pointed directly into the wind during the act of going about.   Compare to In Irons, Miss Stays and Refuses Stays.

Initial Stability - a vessel's tendency to resist heeling from an upright position

Inland Rules - rules of the road that apply in harbors as well as certain rivers, lakes, canals, and other inland waterways in order to avoid collisions. These vary slightly in wording and in the signals that vessels must use from the COLREGS that are used in outer waters and on the high seas. An entirely different set of rules apply when boats are racing, called the International Yacht Racing Rules and created by the International Yacht Racing Union (IYRU) before 1996, and now, the Racing Rules of Sailing, created by the International Sailing Federation (ISAF).

Inspection Port - a watertight covering, usually small, that may be removed so the interior of the hull can be inspected or water removed

International Code of Signals - an international system of signals and codes for use by vessels to communicate important messages regarding safety of navigation and related matters. Signals can be sent by flaghoist (see flags and pennants below right), signal lamp ("Aldis Lamp"), flag semaphore, radiotelegraphy, and radiotelephony.

International Date Line - a line of longitude approximately 180° opposite Greenwich, England. The passing of the sun over this line each day causes the advancement of the date

A chart showing the forty International Maritime Signal Flags.

International Maritime Signal Flags - a set of 40 different flags, each representing a letter of the English alphabet or a number and used to signal from ship to ship by spelling out words, or as single flags with established, standardized meanings.   Compare to Signal Lamps and Semaphore Flags

When flown singly, the flags have the following meanings:
  • A (Alfa) - "I have a diver down; keep well clear at slow speed." - With three numerals, azimuth or bearing.
  • B (Bravo) - "I am taking in, or discharging, or carrying dangerous goods." (Originally used by the Royal Navy specifically for military explosives.)
  • C (Charlie) - "Affirmative." - With three numerals, course in degrees magnetic.
  • D (Delta) - "Keep clear of me; I am maneuvering with difficulty." - With two, four, or six numerals, date.
  • E (Echo) - "I am altering my course to starboard."
  • F (Foxtrot) - "I am disabled; communicate with me." (When flown from an aircraft carrier; "Warning; flight operations underway.")
  • G (Golf) - "I require a pilot." - When made by fishing vessels operating in proximity of the fishing grounds it means: "I am hauling nets." - With four or five numerals, longitude. (The last two numerals denote minutes and the rest degrees.)
  • H (Hotel) - "I have a pilot on board."
  • I (India) - "I am altering my course to port."
  • J (Juliet) - "I am on fire and have dangerous cargo on board: keep well clear of me.", or "I am leaking dangerous cargo."
  • K (Kilo) - "I wish to communicate with you." With one numeral, "I wish to communicate with you by..."; 1) Morse signalling by hand-flags or arms; 2) Loud hailer (megaphone); 3) Morse signalling lamp; 4) Sound signals.
  • L (Lima) - In harbor: "The ship is quarantined." At sea: "You should stop your vessel instantly." - With four numerals, latitude. (The first two denote degrees and the rest minutes.)
    TWO-FLAG SIGNALS
    AC - I am abandoning my vessel. JL - You are running the risk of going aground. QU - Anchoring is prohibited.
    AN - I need a doctor. LO - I am not in my correct position (used by a light vessel.) QX - I request permission to anchor
    BR - I require a helicopter. NC - I am in distress and require immediate assistance. RU - Keep clear of me; I am maneuvering with difficulty.
    CD - I require assistance in the nature of ... PD - Your navigation lights are not visible. SO - You should stop your vessel instantly.
    DV - I am drifting. PP - Keep well clear of me. UM - The harbor is closed to traffic.
    EF - SOS/MAYDAY has been canceled. QD - I am going ahead. UP - Permission to enter harbor is urgently requested. I have an emergency.
    FA - Will you give me my position? QT - You should not anchor. You are going to foul my anchor YU - I am going to communicate with your station by means of the International Code of Signals.
    GW - Man overboard. Please take action to pick him up. QQ - I require health clearance. ZL - Your signal has been received but not understood.
    THREE FLAG SIGNALS
    ZD1 - Please report me to the Coast Guard, New York ZD2 - Please report me to Lloyds, London.
  • M (Mike) - "My vessel is stopped and making no way through the water."
  • N (November) - "Negative."
  • O (Oscar) - "Man overboard." (often attached to the man overboard pole on boats). With a sinister hoist, the semaphore flag.
  • P (Papa) - The Blue Peter. In harbour: All persons should report on board as the vessel is about to proceed to sea. At sea: It may be used by fishing vessels to mean: "My nets have come fast upon an obstruction."
  • Q (Quebec) - "My vessel is 'healthy' and I request free pratique."
  • R (Romeo) - "The way is off my ship." - With one or more numerals, distance (range) in nautical miles.
  • S (Sierra) - "I am operating astern propulsion." - With one or more numerals, speed in knots.
  • T (Tango) - "Keep clear of me; I am engaged in pair trawling." - With four numerals, local time. (The first two denote hours and the rest minutes.)
  • U (Uniform) - "You are running into danger."
  • V (Victor) - "I require assistance." - With one or more numerals, speed in kilometres per hour.
  • W (Whiskey) - "I require medical assistance."
  • X (Xray) - "Stop carrying out your intentions and watch for my signals."
  • Y (Yankee) - "I am dragging my anchor."
  • Z (Zulu) - "I require a tug." - When made by fishing vessels operating in close proximity on the fishing grounds it means: "I am shooting nets." - With one or more numerals, time (UTC). (The first two denote hours and the rest minutes.
  • Substitute or Repeater flags allow messages with duplicate characters to be signaled without the need for multiple sets of flags.
    • First Substitute - Repeats the first alphabet flag, numeral flag, numeral pennant, or repeater above or before it in the same hoist.
    • Second Substitute - Repeats the second alphabet flag, numeral flag, numeral pennant, or repeater above or before it in the same hoist.
    • Third Substitute - Repeats the third alphabet flag, numeral flag, numeral pennant, or repeater above or before it in the same hoist.
    • Fourth Substitute - Repeats the fourth alphabet flag, numeral flag, numeral pennant, or repeater above or before it in the same hoist.
  • Answering Pennant or Decimal Point - Indicates receipt of a message from another vessel - or - When in a flag hoist containing numerals, acts as a decimal point.
  • N and C together (No and Yes) - used as a distress signal.
An image showing the representations of the letters of the alphabet in International Morse Code

International Morse Code - a set of dots and dashes, created by Samuel F. B. Morse in the early 1840s, representing the letters of the alphabet to enable communication for telegraphic transmitters and receivers. Due to its ability to be read by humans without a decoding device and transmitted via many improvised devises like flash lights, tapping on surfaces, reflecting light off mirrors, etc. Morse code is still in use to this day, especially by amateur radio operators.

International Sailing Federation (ISAF) is the world governing body for the sport of sailing and is in charge of the Olympic Regatta, the sailing events held as part of the Summer Olympics, and is most familiar to sailors for the publishing the Racing Rules of Sailing (RRS) which is the international standard used to control the rights of way of racing sailboats and the framework to which sailboat racing is conducted.

Intertropical Convergence Zone or ITCZ - See Doldrums

Intertropical Front or ITF - See Doldrums

Intracoastal Waterway - a system of connected canals, rivers, and bays along the Atlantic seaboard, Gulf of Mexico and other coastlines that enable vessels to travel in protected waters without having to go out into the open oceans

In-water Survey - a method of inspecting the underwater parts of a ship while it is still afloat instead of having to dry-dock it for examination of these areas as was conventionally done

Irish Pennants - rope yarns or loose ends hanging about the rigging or deck. Their appearance is very unseamanlike.

Iron Spinnaker - the auxiliary engine

Isobar - a line on a chart that connects points of equal atmospheric pressure

Isogonic Lines - lines on a chart indicating points of equal magnetic variation

Isolated Danger Marks - an aid to navigation that marks a dangerous obstacle that may be passed on all sides. Use caution when approaching. They are buoys with black and red horizontal bands, may have a letter for identification, and have two black spheres on top. View a downloadable and printable US Coast Guard brochure about nightmarks, buoys and other aids to navigation.

Isotherm - a line on a chart that connects points of equal temperature


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J     (TOP OF PAGE)     (Sailboard Diagram)     (Sailboat Diagram)     (Warship Diagram)

Jacklines - safety lines, often steel wire with a plastic jacket, from the bow to the stern on both port and starboard. The Jack Lines are used to clip the safety harness onto to secure the crew to the vessel while giving them the freedom to walk on the deck, especially in foul weather.

Jack Stay - 1. A stay for racing or cruising vessels used to steady the mast against the strain of the gaff.   2. a rope, rod, or batten along the upper side of a yard, gaff, or boom to which a sail is fastened.   3. a rope or rod running vertically on the forward side of the mast on which the yard moves.

Jack-Yard - an extension for a gaff on a gaff rigged vessel from which a jack-yard topsail may be flown

Jack Tar - a sailor dressed in 'square rig' with square collar. Formerly with a tarred pigtail

Jacob's Ladder - 1. a hanging ladder having ropes or chains supporting wooden or metal rungs or steps. Also called jack ladder or pilot ladder.   2. any ladderlike arrangement aloft other than one of rattled shrouds.

Jam Cleat - a Clam Cleat

Jaws - a forked piece at the end of a gaff or boom, fitting halfway around the mast and held in place by trucks (US) or parrel beads (UK)   Compare to Gooseneck

Jeer - an assemblage or combination of tackles, for hoisting or lowering the lower yards of a square rigged ship

Jeer Capstan - a capstan usually placed between the foremast and mainmast

Jetsam - debris, that remains afloat or washes ashore, that was jettisoned from a sinking ship.   Compare to Flotsam and Lagan or Ligan and Derelict and Marine Debris

Jetty - a man-made extension of the shoreline made to take the brunt of wave action and erosion and protect the waters on its lee side; a breakwater

Jewel Block - a small, single block

Jib - a foresail, a triangle shaped sail forward of the mast that does not reach aft of the mast, as does a genoa

Jibboom - A spar used to extend the bowsprit.

Jib Lead - 1. a fairlead that is used to control the jib sheet.  : 2. On many modern sailing vessels, the Jib Lead is a fairlead that is mounted on a sliding track that can be adjusted to change the position of the jib sheet slightly forward or aft in order to change the angle that the jib sheet pulls on the clew of the jib; thus, the whole mechanism, track and lead, is referred to as the Jib Lead.

Jibe (USA), Gybe (Great Brittan) or Gibe - a downwind change of tack that makes the bow of the vessel pass through dead downwind.

  • Flying Jibe - an accidental jibe caused by a shift in the wind or by sailing by the lee and having the mainsail backed, forcing the boom to swing across the centerline of the vessel. Also called a "Crash Jibe". Look out for the boom!!!
  • Goosewing Jibe - a flying jibe in which the boom rises, catching on the backstay, and thus cannot swing across the centerline of the vessel. If the backstay doesn't break, the boom may be stuck in a position too high to reach with the sail pushing the vessel over on its side. Most modern cruising and racing vessels have booms to short to catch on the backstay.

On a sailboard, this is usually done by rotating the sail on its vertical axis as the sailboard turns through straight downwind. Some of the many types or styles of sailboard Jibes:

Jibe Ho - a notification or warning that a jibe (gybe) has been initiated by the helmsman. Watch out for the Boom!!!

Jibstay - a mast support line that runs from part way down a mast to the bow   Compare to Forestay, Headstay and Backstay

Jiffy Reefing - a method of reducing the area of a sail where the luff is loosened, lowered to its reefing point and hooked, the leech is lowered to the boom and tightened via a leech reefing line, and fastened, but all the reefing points may not be tied. A very fast way to reef a sail. Also called "Slab Reefing."

Jigger - the aft sail on the mizzen mast of a yawl or ketch

Jigger-mast - The fourth mast, although ships with four or more masts were uncommon, or the aft most mast where it is smallest on vessels of less than four masts. Compare to Spanker-mast

Jolly Boat - 1. a light boat carried at the stern of a sailing vessel and used as a tender for the larger vessel.   2. a small pleasure sailboat for use in sheltered waters.

Jumbo - the larger of the headsails

Jumper - all encompassing term for the jumper struts and jumper stays

Jumper Stays - two stays on the upper part of a mast that run over the ends of the jumper struts and form a diamond shape at the top of the mast to add structural integrity against the rearward pull of the backstay. These look like they ought to be called "Jumper Shrouds", but since they are actually structurally involved in the fore-and-aft support of the mast, they are technically "Stays"

Jumper Struts - short spreaders on opposite sides of the mast on larger fractional rigged vessels, just above the forestay and angled slightly forward, and over which the jumper stays run, that help the upper portion of the mast resist the pull of the backstay

Junction Buoy - a buoy marking the crossing of two channels or two parts of a channel, when proceeding from seaward

Junk - 1. old hemp or jute rope, past its useful service life as lines aboard ship. The strands of old junk were teased apart in the process called "picking oakum", used for caulking gaps between planks in the hull and on decks.   2. a type of Chinese sailing vessel

Jury Mast - a replacement for a broken mast. See Jury Rigging

Jury Rigging - makeshift repairs or temporary contrivances, made with only the tools and materials that happen to be on hand. Originally a nautical term, on sailing ships a jury rig is a replacement mast and yards improvised in case of damage or loss of the original mast. While ships typically carried a number of spare parts (e.g., items such as topmasts and many spars of various sizes), the lower masts, at up to one meter in diameter, were too large to carry spares; so a jury mast could be various things. Ships always carried a variety of spare sails, so rigging the jury mast, once erected, was mostly a matter of selecting appropriate sail size for sailors faced with the need to save their ship.

Jute - one of the cheapest natural fibres available to make rope from and has been used for that purpose for centuries; or, if you've ever brought a burlap or gunny sack aboard, you've used jute. You don't see much jute used for small rope on vessels now, but you may see it in use as large hawsers.   See Line


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K     (TOP OF PAGE)     (Sailboard Diagram)     (Sailboat Diagram)     (Warship Diagram)

Keckle - to wind old rope around the anchor line, to preserve its surface from being worn or cut, or to wind iron chains around, to defend from the friction of a rocky bottom, or from ice.

Keckling - any old rope or chain wound about a cable, to preserve the surface of the cable from chafing against the ship's bow or bottom

Kedge - 1. a small anchor   2. to repeatedly place a small anchor away from a vessel and then pull the vessel to the anchor; as when moving against a strong current or pulling a vessel off a reef or shoal.   Compare to Warp

Keel - a vertical fin down the centerline of the bottom of the hull. On most larger boats, the keel is the central structural basis of the hull and will have built-in ballast. The keel is the first part of the structure laid down in the building of a vessel.

Keel Batten - in small boats, a timber attached on top of the keel to provide a surface to which the garboard strakes may be fastened. Also called a Hogging Piece.

Keelhauling - 1. maritime punishment by dragging under the keel of a ship. The sailor had lines attached to his body that would be walked down each side of the vessel after the man was thrown overboard at the bow, then he was hauled in at the stern; or sometimes dragged from one side of the vessel to the other under the keel. Many did not survive drowning or being torn to shreds by barnacles attached to the hull.   2. Today keelhauling may refer to spinnaker sheets getting stuck under the hull after dousing the sail. This occurs frequently in dinghy sailboats such as Laser 2 because nothing prevents the sheet from being pulled under the bow.

Keel Stepped - a mast that is stepped (placed) on the keel at the bottom of the boat rather than on the deck. Keel stepped masts are considered sturdier than deck stepped masts, but often get in the way inside the cabin on smaller vessels

Kelson or Keelson - the fore-and-aft timber immediately above and bolted to, the keel of a large wooden ship to strengthen the hull longitudinally. Also called the "false keel or apron."

Ketch - a two-masted ship with its foremost mast being its main mast and a smaller mast mounted forward of the rudder post.   Compare to other sailboat types on this page

Kevel - a strong cleat to which large ropes are belayed.

Kevlar - an expensive synthetic fiber that has been used successfully in some racing sailboat's sails. Its fibers have the tensile strength of steel and virtually no stretch. However, its brittleness and tendancy to deteriorate in sunlight need to be overcome before it will become every sailors tool.

Key - one of a chain of small low lying tropical islands composed of coral or sand. Same as "Cay".

Kicker - a very small outboard motor

Kicking Strap - See Boom Vang

Kick-up - a centerboard or rudder may be "Kick-up", meaning that it will rotate back and upward when it hits an obstacle. Handy in shallow water or when running to the beach. A daggerboard will not "kick-up".

Killick - a small anchor. A fouled killick is the substantive badge of non-commissioned officers in the British Royal Navy. Seamen promoted to the first step in the promotion ladder are called 'Killick'. The badge signifies that here is an Able Seaman skilled to cope with the awkward job of dealing with a fouled anchor.

Kilometers Per Hour (KPH) - A measure of speed. 1 kph = .62 mph.

King Plank - the centerline plank of a laid deck. Its sides are often recessed, or nibbed, to take the ends of their parallel curved deck planks.

King Spoke - the top, center spoke on a vessel's steering wheel when the rudder is centered, often decorated with whipping so that it can be identified in the dark by the feel of it.

Kink - the curl of a rope that is twisted too hard, or drawn hastily out of the coil

Kite - another name for Spinnaker

Knee - a triangular block of wood that connects two parts roughly at right angles, eg. deck beams to hull frames or sternpost to keel

Knightheads - vertical timbers on either side of the stem that add strength to the bowsprit and extra backing to the planks just abaft the stem

Knob - a knot intended to stop fraying of small line (not used on hawsers) or unreeving of a line or add a handhold

Knockabout - See at Types of Sailboats on this page

Knockdown - a circumstance where a vessel is laid over on its beam ends by the wind or waves far enough for water to come over the gunwale

Knot - 1. a unit of wind or sailing speed, one knot=6,076 feet per hour, one nautical mile per hour. 10 knots is equivalent to 11.5 mph and 18 kilometers per hour (kph). (Note: The expression "knots per hour" is incorrect since that would be redundant and describe acceleration not speed; knots per hour per hour.)   2. In general, all complications tied in cordage where one line or part of a line passes over or around and/or through another, except accidental ones, such as tangles, snarls and kinks, and complications adapted to storage, such as coils, hanks, skeins, balls, etc. In a narrower sense, knots do not include bends, hitches, splices, and sinnets. In the narrowest sense, only knobs, intended to stop fraying or unreeving of a line or add a handhold, are knots. Eight of the most important knots for a mariner to know are: Overhand Knot; Figure-Eight Knot; Clove Hitch; Reef Knot; Bowline; Sheet Bend; Two Half Hitches; and the Midshipman's Hitch or Taut-line Hitch

Some confusing terms in Knotting:
      First of all, you need to know which end is which. Let's say you're working with a 20 foot rope and the far end is tied to something. There are several terms that apply:

  • Bitter End or Standing End - This is the far end that is attached to something. This term evolved from tying the end of the anchor rode to the bitts, but it could be the end of your bow painter that is tied to the boat.
  • Free End or Working End - This is the end that you are working with and are going to tie a knot in because it is free to work with.
      The rest of the rope or line:
  • Standing Part - This is that 10 - 15 feet of rope that is inactive, between the part that you are going to tie the knot in (Free End or Working End) and the far end (Bitter End).
  • Bight - This is any central part of the rope that is not the ends or the standing part.
      More confusing terms: Perhaps remembering B-L-T will help remembering the difference between the first three (which are not knots) on this list. The amount of curve in the line increases from Bight to Loop to Turn.
  • Bight - a curve in a line no greater than a semicircle. This is not a knot, but may be used to create one.
  • Loop - a curve in a line greater than a semicircle and in which the ends do not cross. This is not a knot, but may be used to creat one.
    • Open Loop - a U-shaped loop in which the ends are separated
    • Closed Loop - a loop in which the ends touch but do not cross
  • Turn - a curve in a line making a complete circle and in which the ends cross. This is not a knot, but may be used to create one.
  • Round Turn - a curve in a line that makes two complete circles and in which the ends cross. This is not a knot, but may be used to create one.
  • Riding Turn - a section of rope that passes on top of another section of rope, often parallel or at only a slight angle to the section below. Examples of riding turns can be seen in both the Constrictor knot and the Strangle knot. The second course of wrappings in some seizing knots can be referred to as riding turns. The formation of an unintentional riding turn on a sailing winch can cause it to jam.
  • Bend - an actual knot that ties two lines together
  • Hitch - a knot that secures a rope or line to another object, as a stanchion or bollard

Rope knots can basically be divided into the following groups and many knots can belong to more than one group:

  • Knobs - used to stop fraying or unreeving of a line or add a handhold.
    • Overhand Knot - the simplest knot, knob, and stopper knot, used to keep a rope from unraveling, passing through a hole, or to create a hand-hold on a line. It should be used judiciously, however, because, although it is very secure, it is also very permanent and hard to untie. The Overhand Knot is one of the eight knots everyone should know.
  • Stopper Knots - formed to keep a rope from slipping through a hole or handhold.
    • Overhand Knot - the simplest knot, knob, and stopper knot, used to keep a rope from unraveling, passing through a hole, or to create a hand-hold on a line. It should be used judiciously, however, because, although it is very secure, it is also very permanent and hard to untie. The Overhand Knot is one of the eight knots everyone should know.
    • Figure-Eight Knot - a very good stopper knot, used to keep a line from passing through a block or fairlead. Although it will pull down tight, it is significantlyl easier to untie than an overhand knot. One of the eight knots everyone should know.
  • Bends - join two lines by intertwining them, without splicing, or sewing.
    • Sheet Bend or Becket Bend or Weaver's Knot - a simple bend used to tie two lines together, identical in structure to the bowline, except it ties two lines together instead of tying a loop in one line. The Sheet Bend is one of the eight most useful knots a sailor needs to know.
  • Coils - used to tie up lines for storage.
  • Hitches - a knot that secures a rope or line to an object and is tied directly around or to that object, as a stanchion or bollard. Many hitches capsize (fall apart) if removed from the object to which they are tied.
    • Bowline - a simple hitch and a loop knot used to tie a fixed loop at the end of a line, identical in structure to the sheet bend, except it is tied in one line instead of tying two together. It is simple, strong, virtually slip proof, and easy to untie if not under strain. The bowline is one of the eight most useful knots a sailor needs to know.
    • Clove Hitch - a simple hitch used to tie a line to a post. Effective in its purpose, but spills easily. It should be finished with at least one half hitch over the standing end of the line, if not two. The Clove Hitch is one of the eight most useful knots a sailor needs to know.
    • Two Half Hitches - a simple, but dependable hitch with many uses. Two Half Hitches is one of the eight most useful knots everyone should know.
    • Midshipman's Hitch or Taut-line Hitch - a hitch to use when you need to periodically adjust the length of a line under tension. The Midshipman's Knot is one of the eight easy knots all people should know.
  • Binding Knots - much like hitches. They are used to bind either lines or objects together. Their aim is to keep objects bundled or in place.
    • Reef Knot or Square Knot - a simple binding knot, used to tie two ends of a single line together such that they will secure something; like a sail to a boom (reefing), or a bundle of small objects together. This knot should not be used to bend two lines together, as it can easily capsize or slip. The Reef Knot is one of the eight knots everyone should know.
  • Splices - describes the act of joining the ends, or the end and a standing part, of rope by interweaving strands. They are not knots in themselves.
    • Short Splice - a method for interweaving the strands of rope or cable in order to join two lines in a short distance. A short splice increases the diameter of a line significantly and may jam going through a block.
    • Long Splice - a method of joining two ropes or cables by interweaving the strands of rope without increasing the diameter. A long splice will go through a block without jamming. It is not as strong as a short splice, but keep in mind, long splices are what hold the cables together on overhead gondolas and trams at ski resorts, so they can be pretty strong; the longer the splice, the stronger.
    • Back Splice - an end section of rope that has been unlayed, reversed, and woven back into itself in order to keep it from unraveling and add weight to the end.
    • Eye Splice - a fixed loop in the end of a line made by doubling a line back on itself and either interweaving the strands back into the lay of the rope, or tucking the end of a double-braided line back into the core.
  • Lashings - used to hold spars or poles together.
  • Loops - serve the same purpose as hitches, but are tied in hand and placed around an object instead of being tied directly to the object. They are used to tie, or secure, a line to another line or an object. They can be formed at the end or midway in a length of rope.
    • Bowline - a simple hitch and a loop knot used to tie a fixed loop at the end of a line, identical in structure to the sheet bend, except it is tied in one line instead of tying two together. It is simple, strong, virtually slip proof, and easy to untie if not under strain. The bowline is one of the eight most useful knots a sailor needs to know.
  • Sennits or Plaits - weaving several lines together to form a pattern and a cohesive structure.
  • Whipping - a binding knot tied with small line on the end of a larger line, used to prevent the end of the larger line from fraying.
  • Seizing - used to hold two lines or two parts of the same line together.
  • Trick Knots - used as part of a magic trick or a puzzle.
  • Decorative & Miscellaneous - knots that have decorative, dress or multiple category characteristics.
For animated "How To" drawings of many knots, see Andy's World of Knots at Marine News and click on "Rope Knots" in the Blue Horizontal Rule.

Know the Ropes - being familiar with the miles of cordage and ropes involved in running a ship.


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L     (TOP OF PAGE)     (Sailboard Diagram)     (Sailboat Diagram)     (Warship Diagram)

Ladder - On board a ship, all "stairs" are called ladders, except for literal staircases aboard passenger ships. Most "stairs" on a ship are narrow and nearly vertical, hence the name

Lagan or Ligan - cargo or equipment thrown into the sea but attached to a float or buoy so that it can be recovered.   Compare to Jetsam and Flotsam and Derelict and Marine Debris

Laminate - 1. a surface created by bonding multiple layers together.   2. to create a single surface by bonding multiple layers together

Land Effect - Coastal Refraction

Land Lubber - A person unfamiliar with the ways of the sea

Landfall (Make Landfall) - the first sighting of land when coming in from the sea. Compare to Offing

Lanyard - 1. a line attached to any small object for the purpose of securing the object to something else   2. a line that reeves through a deadeye

Lapper - a foresail which extends back of and overlapping the mast, such as a 110% genoa jib or larger

Lapstrake - See Clinker Built.   Compare to Carvel Built

Larboard - Port. Left side of the ship when looking forward. Archaic form using Starboard and Larboard.   See General Shipboard Directions illustration.

Lateen Rig - an isosceles triangular sail set on a long yard mounted at an angle on the short mast, and running in a fore-and-aft direction at approximately 45°. The angled yard allows the head of the sail to be well above the height of the mast and a modern modification is to add a boom to the foot of the sail. The lateen sail pivots around the mast and will have a "bad tack".   Compare to other rig configurations.

Lateral Resistance - the resistance to the leeway or sideways movement, determined by the amount of heel and keel or centerboard below the waterline and the angle of the keel

Lateral System - a system of aids to navigation in which characteristics of buoys and beacons indicate the sides of the channel or route relative to a conventional direction of buoyage (usually upstream)

Latitude - the angular distance from the equator, measured northward or southward, along a meridian from 0° at the equator to 90° at the poles. It is designated North (N) or South (S) to indicate the direction of measurement and expressed in Degrees, Minutes and Seconds. Compare to Longitude

Launch - 1. to move a vessel from land to water.   2. a rather large, open motorboat used to move people and stores from land or dock to a moored boat or ship

Lay - the Lay of a twisted (not braided) rope or cable is the direction in which its strands are twisted, right handed or clockwise (Z-twist), or left handed or counter-clockwise (S-twist); usually right handed. Braided line has no lay since strands go both clockwise and counter-clockwise.

Lay a Mark - to be able to sail to a mark without having to tack.

Lay down - to begin construction on a vessel in a shipyard

Laydown Jibe (Gybe) - a downwind change of direction in which the sailor carves the board hard, positions the sail almost on the water (lays down) on the inside of the turn, and leans well over the sail during the first portion of the middle of the turn, before flipping the sail   See "Jibe"

Lay Line - imaginary lines forming a "V" downwind from a windward mark and that lead to the windward mark on port and starboard tacks without sailing further than necessary. In racing, you should stay between the lay lines to get to the windward mark. Sailing outside them means you have "overstood" the mark and waisted distance.

Lazarette - spaces below the deck that are designed for storage

Lazyjacks - lines from topping lifts to under the boom which act as a net to catch the sails when lowered

Leach - See Leech below.

Lead pronounced "Led" - a weight attached to a line and used to measure the depth of water.

Lead pronounced "Leed" - a long, narrow, navigable passage through pack ice, between rocks, or shoals, etc.

League - a unit of length, equal to three nautical miles (3.000 006 027 3 miles)

Leather - a protective covering on the portion of an Oar that sits in the oarlock or thole pins. Usually made of leather, but sometimes of canvas.

Lee - a shortened version of leeward. All of the area downwind of the centerline of a watercraft.

Lee Board - pivoting board(s) on either side of a sailboat that does not have a hole in the bottom for a centerboard or daggerboard; which serve the same function as a centerboard. The board to leeward is dropped, the board to windward is kept up. They must be raised and lowered as the craft jibes or tacks.

Leech or Leach -1. the aft or trailing edge of a fore-and-aft sail, triangular or quadrilateral   2. the leeward edge of a spinnaker; 3. a vertical edge of a square sail.

Leech Cord - a small line running through the tabling on the leech of a sail that can be tightened to reduce the fluttering of the trailing edge of the sail in certain conditions. Don't forget to loosen it when it is not needed!   Also called a "Pucker Line" or "Pucker String".

Leech-line - a strong, thin line running inside the leech of a sail to add tension, or cup, to the leech.

Lee Cloth - a cloth hung on the lee side of a berth (the down side when the boat has heel to it) to keep one from rolling out of their bunk

Lee Helm - a tendency of a vessel with poorly trimmed sails to continually turn downwind on its own or if the helm is released.   On a sailboard, this can be corrected by moving the mast base forward in the mast track.   Opposite of Weather Helm.   See Balanced Helm

Lee Side - the side of a vessel sheltered from the wind; opposite of Weather Side or Windward Side

Lee Shore - the shore downwind of a ship. A ship which cannot sail well to windward risks being blown onto a lee shore and grounded.

Leeward - downwind. All of the area downwind of the centerline of a watercraft.

Leeway - the amount that a vessel is blown leeward (downwind) by the wind.   Compare to Pitch, Roll, Yaw, Headway, Sternway, Drift, Surge, and Heave

Left-Hand Lay - stranded (rather than braided) rope made with a twist to the left; called "S-Twist". Most rope is Right-Hand Lay; called "Z-Twist"

Legend - the title and explanation of symbols on a chart, map, illustration, diagram, etc.

Length At Waterline - a straight line measurement of the length of a vessel at the waterline. This length changes as a vessel is loaded and sits lower in the water and is usually much shorter than the Length Over All. Originally Load Waterline Length. Abbreviated "w/l", or "LWL".

Length Of Deck - a straight line measurement of the length of a vessel's weather deck. Abbreviated "LOD".

Length Over All - a straight line measurement of the maximum length of a vessel from the two points on the hull (does not include the bowsprit) most distant from each other. Abbreviated "LOA","oa", "o/a", or "o.a.".

Lesser Ebb - the weaker of the two ebb currents occuring in a tidal day

Lesser Flood - the weaker of the two flood currents occuring in a tidal day

Letter of Marque - a government license authorizing a person (known as a privateer) to attack and capture enemy vessels and bring them before admiralty courts for condemnation and sale.   Also see Pirate and Privateer

Lie To - to remain in practically the same position without anchoring. This may be done in a sailing vessel by dousing sail, reducing sail, or heaving to.

Lifeboat - 1. A small, shipboard boat, kept on board a larger vessel and used to take crew and passengers to safety in the event of the ship being abandoned.   2. A rescue boat, usually launched from shore, used to rescue people from the water or from vessels in difficulty.

Life Buoy - a flotation device, often in the shape of a ring or horseshoe that should be thrown overboard and as close as possible to a person that has fallen off a vessel and into the water, to help them stay afloat until rescued. Next, throw the Overboard Pole near them to mark the location.

Lifeline - a cable fence that surrounds the deck to assist in the prevention of crew falling overboard

Life Preserver - a flotation vest, coat, belt, ring, or cushion worn to increase your chance of survival in the water. Also called a Personal Flotation Device or PFD

Liferaft - an inflatable, covered raft, used to escape to safety, in the event of a vessel being abandoned.

Life Ring - a circular flotation device that should be thrown overboard and as close as possible to a person that has fallen off a vessel and into the water, to help them stay afloat until rescued. Next, throw the Overboard Pole near them to mark the location.

Lift - 1. a shift in wind direction away from the bow of the vessel, thus allowing a vessel that is beating to windward to head up again, thus fetching the mark easier. Opposite of a Header.   2. the force created by a keel, daggerboard, centerboard, leeboard, or fin that allows the vessel to sail upwind.   3. Lines attached to the top of the yards near the yardarms and to the masthead, then run back to the deck, and used to raise and lower the yards of a square rigged vessel

Ligan - see Lagan

Light - a beacon with a light attached to it to help see and identify it at night. View a downloadable and printable US Coast Guard brochure about nightmarks, buoys and other aids to navigation.

Light Airs - wind that moves at 12 mph (10 knots) (18 kph) or less. Good winds for using a Genoa, instead of a jib, on a knockabout or sloop and for the first day or two learning to sail a sailboard.   See Airs

Lighter - a flat-bottomed boat for carrying heavy loads across short distances (especially for canals or for loading or unloading larger boats).

Lighthouse - a sturdy, distinctive structure exhibiting a major navigational light. View a downloadable and printable US Coast Guard brochure about nightmarks, buoys and other aids to navigation.

Lightship - a distinctively marked vessel anchored or moored at a charted point to serve as an aid to navigation. It has a characteristic light or lights, and usually other aids. View a downloadable and printable US Coast Guard brochure about nightmarks, buoys and other aids to navigation.

Light Wind - air that moves at 12 mph (10 knots) (19 kph) or less and is good for Never Evers and beginners learning to sail a sailboard.   See Light Airs.

Light Wind Sails - a set of sails for use in low velocity breezes and racing; also called "Racing Sails". See Sail on this page or Sail Plan at Wikipedia.org

Lignum Vitae - a dense tropical wood typically used in the manufacture of blocks, deadeyes, and other heavy-stress marine fittings before metal replaced it

Limb - 1. the graduated, curved part of an instrument for measuring angles.   2. the circular outer edge of a celestial body, particularly with respect to the top (upper limb) or bottom (lower limb)

Limber Hole - notches cut in the lower edges of frames so that water can drain to the lowest part of the ship (Bilge) in order to be pumped out

Line - the correct nautical term for rope or cordage aboard ship. A line will always have a more specific name, such as "mizzen topsail halyard" or "mainsheet", which describes its specific use. Line is made from many natural and synthetic fibers including: Sisal, Hemp, Jute, Manila, Polypropylene, Nylon, and Polyester

  • Size of Line:   Fiber line is measured by its circumference in inches with the exception of "small stuff" which is fiber line 1 3/4 inches or less in circumference. It has three strands and the number of threads it contains determines its size. Small stuff will range in size from 6 to 21 threads. To determine the number of threads, count the number in one strand and then multiply it by three. Small stuff is used for lashing material and heaving lines. Fiber line between 1 3/4 and 5 inches in circumference is referred to as line, and line over 5 inches in circumference is referred to as hawser. Hawsers are used for mooring and towing large ships and barges. The fiber forestay on a square-rigged ship in the age of sail was frequently 10" or more.

Liner - a Ship of the Line: a major warship capable of taking its place in the main (battle) line of fighting ships. Hence, the modern term for most prestigious passenger vessels

Linstock - a staff with one end forked to hold a match, in the age of sail, used in firing cannon.

Linestopper - an ambiguous name for either a Cam Cleat or a Clam Cleat

Lines Plan - a set of line drawings showing the shape of a hull as delineated by the sections, buttocks, waterlines, and diagonals and usually including a profile, half-breadth view, body plan, and a table of offsets.   Compare to Sail Plan

Lip - the lip of a wave is the crest, where it is curling over and breaking.

List - the leaning of a boat to the side because of excess weight on that side

Lizard - a short line with a loop or small block through which another line may be run, that is easily attached where needed

LOA - Length Over All

Load Waterline (LWL) - the designed waterline of a boat to which it is expected to sit when fully equipped and at its maximum load. A vessel loaded such that its boot top is below water level is in extreme danger of either sinking or, if the overload is on or above decks, capsizing and turtling due to its new high center of gravity. Also, if a hull is given a new coat of paint, it extremely important that its boot top be repainted at the proper height on the hull.

Local Meridian - the meridian through any particular place or observer

Lock - an enclosed chamber in a canal, dam, etc., with gates at each end, for raising or lowering vessels from one level to another by admitting or releasing water.

Locker - a storage compartment on board a vessel

LOD - Length Of Deck

Loft - to scale up and draw a full sized lines plan on a large floor in preparation to construction of a vessel. The final drawing is called the "lofting".

Log - 1. a device for measuring the speed or distance, or both, traveled by a vessel. See Chip Log and Dutchman's Log  2. a Deck or Ship's Log

Loggerhead - 1. an iron ball attached solidly to a long handle, used for driving caulking into seams and (occasionally) in a fight. Hence: 'at loggerheads'.   2. a rounded post, in the stern of a whaleboat, around which the harpoon line is passed.

Long Board - a sailboard that is more than 11 feet (336 cm) long

Longitude - is the arc of a parallel or the angle at the pole between the prime meridian, which passes through Greenwich, England, and the meridian of a point on the earth, measured eastward or westward from the prime meridian through 180°. It is designated East (E) or West (W) to indicate the direction of measurement and expressed in Degrees, Minutes and Seconds. Compare to Latitude

Long Splice - a method of joining two ropes or cables by interweaving the strands of rope without increasing the diameter. A long splice will go through a block without jamming, but it is not as strong as a short splice.

Look Alive - an admonition to be alert

Loom - the round shaft of an Oar

Loop - 1.a curve in a line narrower than a semicircle, but with the ends not crossed. Compare to Bight and Turn   2. In sailboarding, a complete forward or backward vertical rotation, above the water's surface, of the sailboard, rig, and sailor, over the mast and back onto the water's surface

Loose Cannon - 1. An unsecured cannon on deck and weighing thousands of pounds, would crush anything and anyone in its path, and possibly even break a hole in the hull, thus endangering the seaworthiness of the whole ship, thus...   2. An irresponsible and reckless individual whose behavior (either intended or unintended) endangers the group to which he or she belongs.

Loose Footed - a sail that is not connected to a boom along its foot; also, foot loose

Loosen Sail - to unfurl sails and prepair them for use

LORAN - (LOng RAnge Navigation) a radio navigation system which enables ships and aircraft to determine their position and speed from low frequency radio signals transmitted by fixed land based radio beacons to a ship's receiver unit. The most recent version of LORAN in use was LORAN-C, which operated in the low frequency (LF) portion of the radio spectrum from 90 to 110 kHz. In recent decades, LORAN use has been phased out in the United States and Canada. The United States Coast Guard (USCG) and Canadian Coast Guard (CCG) ceased transmitting LORAN-C (and joint CHAYKA (Russian version)) signals in 2010, with the satellite-based Global Positioning System (GPS) being the primary replacement. However, there have been attempts to enhance and re-popularize LORAN, mainly to serve as a backup and land-based alternative to GPS and other satellite navigation systems. There are times of the day (near sunrise and sunset), and locales, like the Virgin Islands, that LORAN is not accurate.

Lower High Water or Tide - the lower of two high tides occurring during a tidal day

Lower Low Water or Tide - the lower of two low tides occurring during a tidal day

Lower Shrouds - the pair of support lines that run from the chain plates at the sides of the boat to just below the spreaders

Low Tide - the minimum height reached by a falling or receding tide

Low Water Inequality - the difference between the height of the two low tides in a tidal day

Lubber Line or Lubber's Line - a fixed vertical line inside a compass case indicating the direction of the ship's bow and corresponding to the vessel's centerline. This indicates where the vessel is pointed, but because of leeway caused by wind, or movement caused by currents, it is not necessarily the direction you are travelling.

Luff - 1. the front edge of a sail   2. Loosening a sheet so far past optimal trim that the sail is no longer completely filled with wind.   3. the flapping of the sail (luffing) from having wind traveling down each side at the same velocity because the vessel is pointed too high on the wind or the sail is let out too far

Luff Up - to steer a sailing vessel more towards the direction of the wind until the pressure is eased on the sheet

Lug - See lugsail

Lugger - See at Types of Sailboats on this page

Lugsail - a quadrilateral sail set on a yard, whose halyard is secured closer to one yardarm than the other, thus making the yard set with one end higher than the other and the sail fly fore-and-aft, and whose fore end of the yard is not attached to the mast; as in gaff rigged sails. There are three sorts of lugsail: the standing lug, in which the yard remains on one side of the mast and the tack is set close to the mast, the balance lug (often, incorrectly, balanced lug), which resembles the standing lug, but sets a boom, which continues as far forward of the mast as the leading edge of the yard, and the dipping lug in which the yard is dipped around the mast when going about so that the sail draws away from the mast on each tack.
     The advantages of the dipping sail occur because the set of the sail is not deformed by pressing against the mast. This allows a more efficient air flow and reduces wear of the canvas. Its disadvantage is that with any but a very small sail, a downhaul is needed and the size of the sail which can be manipulated in this way is limited.   Compare to Gaff Rigged   See more at Lugger at Wikipedia.org

Lull - a temporary calm in the wind

Luminous Range - the extreme distance at which a light can be seen when limited only by the intensity of the light, clearness of the atmosphere, and sensitivity of the observer's eyes

Lunch Hook - a small anchor too small for permanent anchoring

LWL - Load Waterline Length

Lying Ahull - waiting out a storm by dousing all sails and simply letting the boat drift. Usually very uncomfortable and many times, dangerous


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Magazine - the room for storage of munitions and powder

Magnetic Azimuth - the horizontal direction of a celestial point from a terrestrial point, relative to magnetic north

Magnetic Bearing - an absolute bearing using Magnetic North rather than True North as a reference. See also: Absolute Bearing, Relative Bearing, True Bearing, and Bearing

Magnetic North - in the direction of the northern pole of the earth's magnetic field which differs from True North, the northern point of the earth's axis. The two points are not geographically the same and thus cause variations in compass readings that need compensation as a vessel moves about the seas. Compare to True North

Magnetic Storm (Geomagnetic Storm) - violent, extended disruptions of the earth's magnetic fields caused by solar flares

Main Mast - the tallest mast on a sailing vessel

Mainsail - the largest upwind sail on a vessel's main mast

Mainsheet - the line that controls the boom on a mainsail

Make Fast - the action of securing an object or line to something

Make Sail - to set the sail or sails of a boat or increase the amount of sail already set

Manila or Manilla - a natural fiber that ropes can be made of similar to hemp; largely replaced by synthetic fibers, but you'll still see lots of large hawsers made of this fiber. Manila is a strong fiber that comes from the leaf stems of the abaca plant, a part of the banana family. Varying in length from 4 to 15 feet in their natural state, the fibers have the length and quality which gives manila rope relatively high elasticity, strength, and resistance to wear and deterioration; and it floats.   See Line

Man-of-War - any warship, regardless of size or configuration, from the Age of Sail

Man o' War   (Portuguese Man o' War) - a very poisonous, floating, colony of sea animals that appear to be a light blue, purple, or mauve, air bag about 10 to 30 centimeters long with tentacles three to thirty three feet long. Don't even think about touching in the water or picking one up on the beach. You will get severe burns.

Man Overboard Pole - a long pole, that should be within reach of the helmsman, that is tossed into the water immediately after the life buoy or ring, when anyone falls into the water off a boat in order to place a highly visable marker in close proximity of the man overboard. The pole is wood or hollow in order to float, has a colored flag, often the "A" (Alpha) flag, or bright upper tip and is weighted at the bottom just enough to make the pole stand on end while floating in the water.

Marconi Rig - another name for Bermudan Rig where the mainsail is triangular, rigged fore-and-aft with the luff fixed to the mast. Refers to the similarity of the tall mast to a radio aerial.

Marina - a docking facility for small boats and yachts

Marine Debris on Hawiian Coast
Marine Debris on Hawiian Coast

Marine Debris - typically defined as any man-made object discarded, disposed of, or abandoned that enters the coastal or marine environment. It may enter directly from a ship, or indirectly when washed out to sea via rivers, streams and storm drains.   Compare to Jetsam and Flotsam and Derelict and Lagan or Ligan

Marine Radio - a combined transmitter and receiver and only operates on standard, international frequencies known as channels. Channel 16 (156.8 MHz) is the international calling and distress channel. Channel 9 can also be used in some places as a secondary call and distress channel. Installed on all large ships and most seagoing small craft, it is used for a wide variety of purposes, including summoning rescue services and communicating with harbours, locks, bridges and marinas, and operates in the VHF frequency range, between 156 to 174 MHz. Although it is widely used for collision avoidance, its use for this purpose is contentious and is strongly discouraged by some countries, including the UK.

Marine Railway - a track system in marinas, used to haul boats out of the water or to launch them

Maritime - of or relating to the seas, navigation, shipping, etc.

Maritime Law - law that relates to commerce and navigation on the high seas and other navigable waters and that is administered by the admiralty courts

Mark - a buoy or other object that a racing vessel must leave on a designated side

Marline - light, two-stranded line, formerly made of hemp and sometimes tarred, used for whipping, seizing, serving, and lacing

Marlinspike - a tool used in ropework for tasks such as unlaying rope for splicing, untying knots, or forming a makeshift handle. A marlinspike is basically a rod or bar tapered to a rounded or flattened point, usually 6 to 12 inches long, although sometimes 26" or longer, depending on what ply and size of rope they are intended for.   Compare to Fid

Marlinespike Seamanship - a general term for handling and caring for fiber line and wire rope used aboard ship or in other marine operations

Marry - to unlay the strands of two lines and interlace them prior to splicing them

Martingale - a stay underneath and holding the bowsprit down and running over the end of the dolphin striker in order to counteract the force of the forestay. If there is no dolphin stiker, it is merely a bobstay.

Mast - the usually vertical, aluminum, fiberglass, carbon-fiber, or wooden spar that supports the sail and rigging of a sailing vessel.

A traditional square rigged ship will have up to six masts. The masts of a full rigged ship, from bow to stern, are:
  • Foremast, which is the second tallest mast
  • Mainmast, the tallest
  • Mizzenmast, the third tallest
  • Jiggermast, which may not be present but will be fourth tallest if so equipped
There is no standard name for a fifth mast on a ship-rigged vessel (though this may be called the spanker mast on a barque, schooner or barquentine). Sixth and seventh masts have no standard naming protocol.

Each mast, if wooden, consists of several stacked masts or sections of mast. It would be impossible to carry spare one-piece masts in case one broke, much less remove and step its replacement while at sea, so they are stacked in sections of deminishing girth and weight. This allows spare sections to be carried and replaced as needed.
The Mainmast, which carries the most sail, may consist of three or more sections. Top to bottom they are:
  • Main-Moon-Mast (If equipped) - Highest
  • Main-Sky-Mast (If equipped)
  • Main-Royal-Mast (If equipped)
  • Main-Topgallant-Mast
  • Main-Topmast
  • Mainmast - Lowest

Mast Base - a connection on a sailboard that has one or two male studs that fit into the mast track to attach the mast to the sailboard via the universal joint

Mast Base Extension - a tube attached to the mast base of a sailboard, above the Universal Joint, that is usually adjustable in length, in order to allow the mast to be adjusted to accommodate sails of various sizes (luff length)

Masthead - 1. a small platform partway up the mast, just above the height of the mast's main yard. A lookout is stationed here, and men who are working on the main yard will embark from here.   See also Crow's Nest   2. the top of the mast

Masthead Fly - a wind direction indicator mounted atop the mast. The best indicator of true wind direction when your vessel is not moving and the apparent wind direction when under way.

Masthead Rig - a fore-and-aft sail configuration consisting of a headsail, such as a jib or genoa sail, that reaches all the way to the top of the mast; as opposed to a fractional rig, which does not.   See two sailboats photograph at the top of the page for a comparison.

Mast Heel - a metal casing that may hold the base of the mast in place

Mast Hoop - a ring, usually of wood, that fits around the mast in order to hold the luff of a sail in place and allow the luff to slide up and down the mast as the sail is raised or struck

Mast Protector - a small, partial sleeve that fits around the mast of a sailboard at the point where the boom is connected to reinforce the mast and spread the stresses created by the boom on the mast

Mast Sleeve - a tapered pocket in the luff of a sailboard sail in which the mast resides

Mast Step - the box on a sailing vessel that the base of a mast is set into

Mast Tip Extension - a tube that slips over the masthead on a sailboard in order to lengthen the mast to accommodate sails of various sizes (luff length)

Mast Track - 1. a groove in a mast that the bolt rope of a sail slides into to raise and lower sail   2. a rail attached to the aft edge of a mast on which sliders on the luff of the sail move up and down as the sail is raised and lowered   3. a slot in the deck of a sailboard that the mast base attaches to that lets the mast be moved fore and aft in order to allow adjustment for different sized sails or to make the board sail upwind or downwind more efficiently

Maximum Ebb - the highest speed of an ebb current

Maximum Flood - the highest speed of a flood current

Mayday - a distress call indicating a person or vessel is in grave and imminent danger and needs immediate rescue or assistance. The word "Mayday" should be repeated three times and then the location of the boat should be given along with information about the assistance needed. For further information see: Mayday at Wikipedia.   Compare to Pan Pan and Sécurité

Mean Sea Level - a reference point used as a standard for determining terrestrial and atmospheric elevation or ocean depths and calculated as the average of hourly tide levels measured by mechanical tide gauges over extended periods of time. For more information about sea levels and tide levels, see this NOAA page

Mean Tide Level - the arithmetic midpoint between mean high water and mean low water.   This level is not identical with mean sea level because of higher harmonics in the tidal constituents.

Meat Hook - the sharp, broken individual wire strands in a wire rope or cable; so named because of the ferocity with which they rip or puncture skin. Also called "fishhooks" or "burrs". One or two meathooks can be cleaned off the wire by rubbing up and down the line with a knife perpendicular to the line. The meathooks aren't being cut with the blade but break off at the surface because they are being bent back and forth until they break. If a line has more than a very few meat hooks, it should be replaced.

Mechanical Advantage (Purchase) - mechanical method of increasing an applied force. Disregarding the effects of friction, if a force of 100 pounds applied to a block and tackle is magnified to a force of 400 pounds, the purchase or mechanical advantage is said to be four to one, or 4:1.   See Block

Meridian - a great circle that passes through the earth's geographical poles and at right angles to the equator. A line of longitude. The prime meridial passes through Greenwich England (0° longitude).

Mess - 1. the area aboard ship where meals are eaten   2. a group of crew who live and eat together

Messenger - a light line either thrown or shot from one vessel to another or from ship to shore in order to pull a heavier line that is too heavy to throw. See Heaving Line

Meteorological Tides - a change in water level due to meteorological (atmospheric or weather) conditions.   Also called Storm Tide or Storm Surge

Meter - a unit of length that is 100 centimeters. To convert meters to feet, multiply by 3.28

Midshipman's Hitch or Taut-line Hitch - a hitch to use when you need to periodically adjust the length of a line under tension. The Midshipman's Knot is one of the eight easy knots all people should know.

Miles Per Hour (MPH) - measurement of speed; 10 mph is equivalent to 16 kilometers per hour and 9 knots.

Miss Stays - to fail to get about when an attempt is made to go about. You may end up in irons, or, simply, fall back onto the old tack.   Compare to In Irons, In Stays and Refuses Stays.

Mizzen or Mizzen Mast - the third mast on a ship, the shorter mast behind the main mast on a ketch or yawl or the sail set on that mast

Moderate Airs or Winds - wind that moves at 12 to 24 mph (10 - 20 knots) (18 - 36 kph). Good winds for a Working Jib on a knockabout or sloop and for anyone but a Never Ever learning to sail a sailboard..   See Airs

Moderate Wind - air that moves at 12 to 24 mph (10 - 20 knots) (18 - 36 kph)

Molds - wooden sectional patterns, set on stations across the keel, around which planks are bent to obtain the precise shape of a vessel

Mole - 1. a massive structure, especially of stone, set up in the water, as for a breakwater or a pier.   2. an anchorage or harbor protected by such a structure.

Monel - a strong, rust-resistant metal alloy consisting of approximately 67% nickel, 28% copper, and 5% iron and manganese, and used for fastenings, propellers, and parts of metal instruments

Monkey Deck - a false deck built over a permanent deck. Often used in the bow of larger sailing ships, forward of the anchor windlass and provides a working platform around the portion of the bowsprit as it attaches to the ship

Monkey Fist - a ball woven out of line used to provide heft to heave the line to another location. The monkey fist and other heaving-line knots were sometimes weighted with lead to facilitate more distance of the throw

Monkey Line - a safety line made up with a series of overhand or figure eight knots evenly spaced to assist personnel climbing up and down

Monofilm - a strong, clear, plasticized sail cloth that is used in most modern sailboard sails

Monohull - a vessel with a single hull, as opposed to a multi-hull boat like a catamaran, proa, trimaran, etc.

Moore - to be attached to a mooring. A large ship is said to be moored when it is lying with two anchors down.

Mooring - 1. an anchor or weight, permanently lying on the sea floor, with a buoy attached at the surface, used to hold the boat in a certain area.   2. an arrangement for attaching a boat to a pier or wharf

Mooring Pennant - a line permanently attached to a mooring buoy for securing a vessel to the mooring

Morse Code - See International Morse Code"

Motorboat - a boat whose primary propulsion is via motorized means

Motorsailer - a boat that has a small to significant amount of sail, but whose primary propulsion is via motorized means. These are usually based around a sailing cruiser hull, but instead of the low 'coachroof' over the saloon, most motor-sailers have a raised saloon roof, providing an enclosed wheelhouse with large windows and containing the helm, engine controls, navigational equipment etc, allowing the vessel to be operated from inside as on a standard cabin cruiser motorboat. Usually, a second helm and basic instruments are installed in the cockpit behind the wheelhouse for when under sail or in good weather. Motor-sailers are, naturally, a compromise between a sailing yacht and a motor yacht; not good at either one.

Mousing - turns of twine, or other small line, around the opening of a hook to prevent unhooking

Multi-Hull - any of several designs of vessel with more than one hull; catamaran, trimaran, proa, etc.

Mushroom Anchor - in larger sizes, usually a heavy mooring anchor that will sink into a soft bottom, this anchor is desirable because it has no stock to snag on an anchorline; it is all shank and cup or upside down mushroom shape. Small versions are frequently used for small fishing boats, prams and dingies.


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Nadir - the point on the celestial sphere exactly opposite or vertically below the observer, or 180° from the zenith

Nantucket Sleighride -a term coined by old whalers to explain what happened after they harpooned a whale. (Nantucket Island was considered the whaling capital of the world during the 19th century.) The first harpoon was not intended to kill the whale but only to attach it to the whale boat. The whale would take off pulling the whale boat along at speeds of up to 23 mph (37 kmh). The whale would eventually tire itself out and the leading officer in the boat would then use a penetrating lance to kill the whale.

National Oceanic and Atmospheric Administration - a federal agency in charge of disseminating weather information and nautical charts for the U.S.A.; a great resource for weather information at NOAA.gov

NATO - North Atlantic Treaty Organizition

NATO Phonetic Alphabet - the most widely used spelling alphabet. Though often called "phonetic alphabets", spelling alphabets have no connection to phonetic transcription systems like the International Phonetic Alphabet. Instead, the International Civil Aviation Organization (ICAO) alphabet assigns code words to the letters of the English alphabet acrophonically (Alfa for A, Bravo for B, etc.(See below)) so that critical combinations of letters (and numbers) can be pronounced and understood by those who transmit and receive voice messages by radio or telephone regardless of their native language, especially when the safety of navigation or persons is essential. The paramount reason is to ensure intelligibility of voice signals over radio links. The code words are: Alpha, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliet, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu

Nautical Almanac - an annual publication, jointly published by the U.S. Naval Observatory and H.M. Nautical Almanac Office, containing tables of celestial bodies, their positions and movements at specific times, consulted by the navigator in preparation for taking sightings of celestial bodies. Such tables were known as "The Ephemeris" from the 18th C. until 1981 when it was jointly published by the US and Britian; also the Astronomical Almanac.

Nautical Mile - a measurement of distance that is equal to 1852 Meters (1.852 Kilometers), 6,076.11549 U.S.feet, or 1.151 Statute (Land Measurement) Miles or .333333333 Nautical League or 1,012.689143 Fathoms

Nautical Twilight - See Twilight

Naveam - an urgent notice of dangers to navigation in the Eastern Atlantic or Mediterranean waters

Navigable - water with sufficient depth to permit a vessel to pass without running aground

Navigable Semicircle - that half of a cyclonic storm area to the left of the storm track in the northern hemisphere, and to the right of the storm track in the southern hemisphere. In this semicircle the winds are weaker and tend to blow a vessel away from the path of the storm.

Navigation - the art and science of moving a vessel safely from one point to another

Navigation Lights - lights shown by a vessel at night that show its course, position, and status; such as anchored, fishing, or towing

Navigational Planets - the four planets commonly used for sightings in celestial navigation; Venus, Mars, Jupiter, and Saturn

Navigation Rules - Rules of the road that provide guidance on how to avoid collision and also used to assign blame when a collision does occur.   See Right of Way

Navigation Weir - a lock that, after being partially emptied, is opened suddenly to send a boat over a shallow place with a rush of water. Also called a, staunch or stanch, or flash-lock.

Neap Tide - a lower tides produced when the sun and moon are at a right angle in relation to the earth, as at 1st or 3rd quarter, and their total effect is lesser.   Compare to Spring Tide

Never Ever - a person who has Never Ever done something. A neophyte, rookie, etc. In a broad sense, someone who is very new at a learning experience.

Niggerhead - 1. a former British term for a black iron post for mooring ships, made from an old cannon partially buried muzzle upward, with a slightly oversize black cannonball covering the hole.   2. an old sailors' term for an isolated coral head; notorious as navigation hazards.   3. an old U.S. Navy term for a small winch, a Capstan

Nightmark - an object of distinctive characteristics serving as an aid to navigation during darkness. View a downloadable and printable US Coast Guard brochure about nightmarks, buoys and other aids to navigation.

Nipper - a short rope used to bind a cable to the "messenger" (a moving line propelled by the capstan) so that the cable is dragged along too (Used because the cable is too large to be wrapped round the capstan itself). During the raising of an anchor the nippers were attached and detached from the (endless) messenger by the ship's boys. Hence the term for small boys: 'nippers'.

NOAA - National Oceanic and Atmospheric Administration - a federal agency in charge of disseminating weather information and nautical charts for the U.S.A.; a great resource for weather information at NOAA.gov

Nock - the upper foremost corner of a quadrilateral fore-and-aft rigged sail on some sloops; also called the "Throat"

Non-Planing Jibe (Gybe) - a sailboard jibe in which the sailboard either enters or exits the turn at non-planing speed that involves turning the board by either moving the sail forward or moving the back foot out of the strap and placing it on the leeward rail, moving the feet to near the centerline of the sailboard, flipping the sail, then moving the feet into position on the other side of the board; in that order   See "Jibe"

Noose - a closed loop in the end of a line with a running knot (the opposite end of the line passed through the loop)

Nose - another name for the Bow of a sailboard

"No Wake" Speed - See Wakeless Speed

Nun - a type of navigational buoy whose above-water portion is in the shape of a cone or a truncated cone. View a downloadable and printable US Coast Guard brochure about nightmarks, buoys and other aids to navigation.

Nylon - one of the strongest synthetic fibers for making rope or line. It is about 10 percent stronger than polyester fibers, but stretches a little bit more under load, is slightly less abrasion resistant and is slightly less resistant to UV rays. It also resists decay, and fungus growth. It does sink in water, but is soft and easy to tie and untie knots in. It is a great line if you don't mind a little stretchiness. Nylon line is a strong anchor line and the stretchiness works in your favor to lessen the bump that occurs as your boat tightens the line each time a wave comes under the bow.
      Because its filament is stretchy, it is not useful for working sails that must hold their shape; but is just right for deeply cambered, light weight sails like spinnakers.


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Oakum - a preparation of tarred fiber used in shipbuilding, for caulking or packing the joints of timbers in wooden vessels and the deck planking of iron and steel ships, as well as cast iron plumbing applications. Oakum was at one time made from old tarry ropes and cordage of vessels (Junk), and its picking and preparation has been a common penal occupation in prisons and workhouses. In modern times it is made from virgin hemp fibers. White oakum is made from untarred materials. The fibrous material used in oakum is most commonly a hemp or jute fiber impregnated with tar or a tar-like substance. This tar is not the "tar" used on streets and roofs, which is really asphalt, but rather pine tar, also called Stockholm tar, an amber-colored pitch made from the sap of certain pine trees.

Oar - a long spar with a flat blade used for propelling a vessel; usually used in pairs, but may be used singly for sculling. (a Noun) A boatman does not "oar a boat;" he rows it.   Parts are: Blade, Loom, Leather, Button, and Handle

Oarlock - a notch, U-shaped fork, or ring that attaches an oar to the gunwale of a boat and acts as a fulcrum for the oar. Called a Rowlock by the British

Offing (Have an Offing) - to be a considerable distance to seaward, but still within visual contact of land. Compare to Landfall

Offsets - the table of coordinates that supply the full-scale measurements needed to loft a lines plan

Offshore Wind - wind that blows from the land to the water and is perpendicular to the shoreline. A dangerous wind for sailboarders because it makes returning to shore difficult at best, and life threatening if something goes wrong because if something goes wrong, you will be blown away from shore.

Off-the-Wind - 1. downwind   2. In a direction other than close hauled; i.e. a reach or a run.

Off the Lip - a wave sailing maneuver of sailboarders made off the breaking lip of a wave

Oilskins or Oilies - Foul-weather clothing worn by sailors

Old Salt - a very experienced and/or old sailor

On-a-Plane - sailing at a speed that makes the craft skim across the top of the water instead of plowing through it.

One Design - a sailing vessel that is designed for racing a triangular course in which all competitors sail vessels that are identical, and typically, without handicapping; the first one across the finish line wins.

Onshore Wind - wind that blows from the water onto the land and is perpendicular to the shoreline; making it difficult to get away from shore

On the Wind - sailing close hauled

Ooch - a rapid fore-and-aft body movement in order to initiate planing or surfing of a small vessel

Open Boat - a vessel with no decking

Open Class - a sailing race that has no restrictions on equipment used or wind velocity

Orlop Deck - the lowest deck of a ship of the line. The deck covering in the hold

Outboard - 1. away from the centerline of the boat, near the rails or gunwale   See General Shipboard Directions illustration.   2. the use of outboard and inboard varies when a vessel is moored to a pier. The side against the pier is inboard; the side away from the pier is outboard.   3. outside the gunwales or hull   4. a temporarily mounted engine attached to the stern of a vessel

Outdrive - a propulsion system for boats with an inboard engine operating an exterior drive with drive shaft, gears, and propeller. Also called stern drive or inboard/outboard (I/O).

Outfoot - to sail faster than another boat

Outhaul - the line that adjusts outward tension along the foot of the sail along the boom of a sailboat or at the clew of a sailboard sail

Outpoint - to sail closer into the wind than another vessel

Outward Bound - to leave the safety of port, heading for the open sea

Overbear - to sail directly upwind of another ship, stealing the wind from its sails

Overboard - off the decks, over the side and out of the boat

Overboard Pole - a long pole, that should be within reach of the helmsman, that is tossed into the water immediately after the life buoy or ring, when anyone falls into the water off a boat in order to place a highly visable marker in close proximity of the man overboard. The pole is wood or hollow in order to float, has a brightly colored flag, often the "A" (Alpha) flag, or bright upper tip and is weighted at the bottom just enough to make the pole stand on end while floating in the water.

Overfall - dangerously steep and breaking seas due to wind and current that oppose each other in a shallow area

Overhand Knot - the simplest of stopper knots, used to keep a rope from unraveling, passing through a hole, or to create a hand-hold on a line. It should be used judiciously, however, because, although it is very secure, it is also semi-permanent and hard to untie. The Overhand Knot is one of the eight knots everyone should know.

Overhead - the "ceiling," to land lubbers, or, essentially, the bottom of the deck above you or its lining

Overpowered - use of sail area that is too large for the wind velocity

Overreach - to sail on a tack longer than is desirable or was intended; overstand

Oversheet - pulling the clew of the boom of a sailboard across the centerline of the sailboard to windward

Override - a situation where the wraps of a sheet on a winch that are coming from the clew of the sail jump over the tail or end of the sheet that is being pulled on to sheet the sail in. This can cause such a tangle that, with significant wind in the jib, it can get so tight that you can't sheet in any further. The only solution may be to take all the strain off the jib sheet so the wraps can be loosened. This can be accomplished by tying another line on the sheet ahead of the winch and taking the strain with another winch. A second line can be tied to the fouled sheet with a rolling hitch, which won't slip under strain.

Overstand - in racing, to sail beyond the lay lines to the windward mark; overreach

Overtake - to catch a competitor from astern

Overwhelmed - capsized or foundered


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Pacific Iron - an iron ring and a swivel joint that connects the boom to the mast of a sailboat or ship. Also called the Gooseneck   See "Boom Head" for sailboarding

Pack - a large field of floating sea ice that has drifted together

Packing Gland - the sealant around a sliding or rotating shaft, such as a propeller shaft or rudder post, that goes into the Stuffing Box to keep water from leaking into a vessel. Also called the shaft seal.

Pad Eye - a ring fixed to the structure of a ship as a hold for small lines, tackles, etc. Also called a "Lug Pad"   See illustration at Deck Fittings on this page

Painter - a line tied to the bow of a small boat for the purpose of securing it to a dock or shore or for towing

Palm - 1. a heavy leather fingerless glove with a built in thimble used by sailmakers and riggers to assist in sewing heavy materials   2. the broad portion of an anchor fluke.   See Anchor

Pan Pan (Pronounced "Pähn Pähn") - a call indicating an urgent call for assistance MIGHT be needed for you, your vessel, or someone on your vessel within a short time. An example situation that a Pan Pan call would be warranted would be if your engine failed and you might be washed ashore within an hour or two if you can't get it restarted. The words "Pan Pan" should be repeated three times and then the location of your boat should be given along with information about the assistance you MIGHT need. You should then stay in touch with the authorities on a continuing basis to let them know if you have remedied the situation or it has gotten worse and you need assistance or rescue. For further information see: Pan Pan at Wikipedia.   Compare to Mayday and Sécurité

Panting - the pulsation in and out of the bow and stern plating as the ship alternately rises and plunges deep into the water

Paralax Error - the error in reading an instrument, such as a compass or engine guage, due to the difference in distance from the indicator needle to the numerical scale

Parallel - a circle on the surface of the earth, or a similar body, parallel to the plane of the equator and connecting all points of equal latitude, or a closed curve resembling or approximating such a circle

Parbuckle - a mechanism for lifting a roughly cylindrical object such as a spar. One end of a rope is made fast above the object, a loop of rope is lowered and passed around the object, which can be raised by hauling on the free end of rope

Parcel - See at Worm, Serve and Parcel on this page

Parrel - a movable loop or collar, used to fasten a yard or gaff's jaws to its respective mast. Parrel still allows the spar to be raised or lowered and swivel around the mast. It may be made of wire or rope and fitted with parrel beads to reduce friction

Parrel Beads - round rollers strung over a short line called the parrel line.   See Parell above

Partners - frames of timber or steel fitted on the underside of the decks that form a frame to support through-deck structures such as masts, capstans, or sampson posts

Passage - a trip from one port to another. One leg of a voyage.   Compare to Voyage

Patent Log - any mechanical log, especially a taffrail log

Pay Out - to slacken a line or sheet in a controlled manner, so that it may be free to run, but without letting go of it

Peak - the upper, after corner of a quadrilateral fore-and-aft rigged sail

Pedestal - the base for the wheel or helm

Pelorus - a compass card without a directive element (needle), suitably mounted to provide means for measuring bearings. Also called a Dumb Compass

Pennant or Pendant or Pennent or Pendent - 1. a long, tapering flag or burgee of distinctive form and special significance, borne on naval or other vessels and used in signaling or for identification.   2. the line by which a boat ties up to a mooring buoy   3. a length of wire or rope secured at one end to a mast or spar and having a block or other fitting at the lower end   4. in general, any line hanging from a point to which it is attached and awaiting its free end to be tied to something else

Perigean Tides - tides of increased range occurring when the moon is near perigee

Perigee - the orbital point nearest the earth when the earth is the center of attraction (as in the case of the moon)

Perihelion - the orbital point nearest the sun when the sun is the center of attraction (as in the case of a planet)

PFD - Personal Flotation Devise; a life jacket

Phonetic Alphabet - Code words that represent the letters of the alphabet for use in clarifying vocal transmissions via radio and telephony. Though often called "phonetic alphabets", spelling alphabets have no connection to phonetic transcription systems like the International Phonetic Alphabet. Instead, the International Civil Aviation Organization (ICAO) alphabet assigns code words to the letters of the English alphabet acrophonically (Alfa for A, Bravo for B, etc.(See below)) so that critical combinations of letters (and numbers) can be pronounced and understood by those who transmit and receive voice messages by radio or telephone regardless of their native language, especially when the safety of navigation or persons is essential. The paramount reason is to ensure intelligibility of voice signals over radio links. The code words are: Alpha, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliet, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu

Pile or Piling - a wood, concrete, or metal pole driven into the bottom. It may be created to support a pier, protect a wharf or just to tie up to.

Pilot - a navigator especially knowledgeable of and qualified to navigate a vessel through specific, difficult waters, e.g. harbor pilot etc.

Pilothouse - a small cabin on the deck of the ship that protects the steering wheel and the crewman that is steering

Piloting - 1. the act of guiding a ship through near-shore hazards by a pilot (See above).   2. determining a vessel's position and directing her course by means of bearings to landmarks or by buoys and soundings when near land. This takes the place of celestial navigation used at sea and out of the view of land.

Pinch - to sail as close as possible into the wind. Your sails may be slightly backwinded at the leading edge, luffing, and you will not be sailing as fast to windward as you could.

Pin Rail - a section of a rail, or at the base of the mast that has holes in it that the belaying pins fit into for making lines fast

Pinnace - 1. a ship's boat or tender   2. a full rigged, usually three masted, square rigged ship with shallow draught developed by the Dutch in the early 17th century. Pinnaces saw use as merchant vessels, pirate vessels and small warships.

Pintles - small straight pins secured to a rudder that fit into the gudgeons on the sternpost of very small boats, thus holding the rudder in place and allowing the rudder to pivot

Pipe Down - A signal on the bosun's pipe to signal the end of the day, requiring lights (and smoking pipes) to be extinguished and silence from the crew

Pirate - a person who boards a vessel to commit robbery, plundering, kidnapping, murder, etc., and that does so without the authorization of a national power via a Letter of Marque to conduct hostilities against an enemy. Pirates are still in action today. Be Carefull !!!   Compare to Privateer

Pitch - 1. the theoretical distance a boat's propeller travels in one rotation   2. tar and resin used to caulk the cracks between the planks of a vessel   3. a vessel's motion, rotating about the beam axis so that the bow and stern rise and fall at opposite times. Compare to Headway, Sternway, Roll, Yaw, Leeway, Drift, Surge, and Heave

Pitchpole - To capsize a boat end over end, rather than by rolling over sideways. Pitchpoling bow first happens most often when a boat is running downwind and as a following wave lifts the stern of the boat, the boat accelerates down the face of the wave until the bow submerges and slows; then the stern is lifted over the bow. Even large boats can be pitchpoled bow over stern rearward in extremely high seas. Pitchpoling is the most dangerous means of capsizing because of the forces involved and the chances of heavy objects being hurled around with great force on deck or down below.

Pivot, Snap or Flare Jibe (Gybe) - a downwind jibe in which the stern or tail of the sailboard is sunken by moving the sailor's weight back, the stern acting as the pivot point for the turn. The advantage of this jibe is its short turning radius. The short-board Flare Jibe   See "Jibe"

Plane - to travel at a speed that makes your watercraft ride on top of the water instead of plowing through it. This usually entails having about the front two-thirds of the craft out of the water and the back third (or less) skimming over the surface

Planks or Planking - the wooden boards that cover the frames to form the hull of a wooden vessel

Planing Hull - a hull of a vessel designed such that when it achieves a certain speed it will skim across the water rather than push its way through

Planing Jibe (Gybe) - any style of jibe in which the sailboard enters on a plane and exits the turn without having ever come off of a plane   See "Jibe"

Planing speed - the velocity needed to make a specific watercraft transition from plowing through the water to skimming over the surface.

Planks - boards that are nailed to the frames to make up the hull of a wooden vessel. Each continuous line of planks from stem to stern is a strake

Pleasure Vessel License - a type of U.S.Coast Guard documentation that does not allow commercial use of the vessel

Plumbbow - a vessel with a vertical stem or bow

Point - 1. to sail close to the wind.   2. One of 32 points of the 360° compass equal to 11.25°, eight points to a quadrant; used to describe the bearing of an object in relation to your direction of travel or heading. An object might be one, two, or three points "forward of the starboard (or port) beam" or "abaft the starboard (or port) beam". Or it may be one, two, or three points "off the starboard (or port) bow", measuring from dead ahead; or one, two, or three points "off the starboard (or port) quarter", measuring from dead astern.   See Bearings illustration showing Points in a new window.

Point Up - 1. to sail closer to the wind.

Click on IMAGE to open in new window and enlarge.
Points of Sail
An illustration of the various Points of Sail in relation to the wind direction

Points of Sail - the term used to describe a sailing boat's course in relation to the wind direction. See illustration at right.

Pointer Fin or Skeg - a fin shaped long, thin, and narrow. The best fin for sailing upwind. This design has the least resistance for its blade area.

Pole - 1. either of the two points (North and South) of intersection of the surface of the earth or similar body and its axis.   2. Either of two regions of the Earth's surface at which magnetic lines of force are perpendicular to the Earth's surface and to which the needle of a compass points

Poly-Board - a sailboard made with an outer, plastic-like skin of polyethylene or polypropylene. These boards are very heavy and durable; great for real beginners. Also called a Tupperware Board.

Polyester - a synthetic fiber used in sail cloth and ropes. It is 90 percent as strong and has less stretch under load than nylon, is more abrasion resistant, and better resistance to UV light. "Dacron" is a trade name. Don't mistake polypropylene for this. See below.   See Line

Polypropylene - a lightweight, stretchy, slippery, synthetic fiber used in line where flotation is desirable, but high strength is not important. It is also very adversely effected by sunlight, allows many knots to slip and then, holds the shape of the knot after being untied. In My Humble Opinion, in most ways, highly inferior to nylon or polyester lines. Its only redeeming features are that it floats and it's cheap. Don't mistake this for Polyester. See just above.   See Line

Poop - 1. a superstructure at the aft of a ship.   2. the poop deck.

Poop Deck - a high partial deck on the aft superstructure of a ship.

Pooped - 1. swamped by a high, following sea.   2. exhausted.

Port - 1, the left side of the watercraft when viewed from the stern; formerly "Larboard". Marked on vessels with a RED light at night.   See General Shipboard Directions illustration.   2. a city, town, or other place where ships load or unload.   3. a place along a coast in which ships may take refuge from storms; a harbor.

Porthole - an opening in a ship's side, especially a round one for admitting light and air, fitted with thick glass and, often, a hinged metal cover. A window. A porthole is a "Portlight" if it can be opened to admit air, and a "Deadlight" if it cannot.

Portlight - a porthole that can be opened for light and air to pass through

Port Tack - sailing with the wind coming from the port side, with the boom on the starboard side. On a sailboard, your left hand will be your front hand.

Power Jibe - a generic term for all jibes except a beginner's jibe

Pram - a small, flat-bottomed rowboat or sailboat with a square bow and stern, sometimes used as a tender

Pratique - is the permission given to a ship to enter port on assurance from the captain to the authorities that the vessel is free from contagious disease. The clearance granted is commonly referred to as Free Pratique. A ship can signal a request for "Pratique" by flying a solid yellow square-shaped flag. This yellow flag is the Q flag in the set of International Maritime Signal Flags.

Prevailing Wind - the normal wind direction for a specific area and season

Preventer (Gybe Preventer, Jibe Preventer) - a line attached to some part of a boat, or one its parts, to prevent or moderate the effects of an accident; such as the sail control line originating at some point on the boom, leading to a fixed point on the boat's deck or rail (usually a cleat or pad eye) used to prevent or moderate the effects of an accidental jibe.

Prime Meridian - the meridian of longitude 0°, used as the origin for the measurement of longitude. Internationally, the meridian passing through Greenwich, England has been accepted as the Prime Meridian for navigation.

Primer Bulb - 1. a rubber squeeze valve in the fuel line of an outboard engine that, when squeezed, forces gasoline into the carburetor to prime the engine.

Privateer - A privately-owned ship authorized by a government (by means of a Letter of Marque) to conduct hostilities against an enemy. Privateering was a way of mobilizing armed ships and sailors without having to spend public money or commit naval officers. The cost was borne by investors hoping to profit from prize money earned from captured cargo and vessels. The proceeds would be distributed among the privateer's investors, officers, and crew. Privateering was considered an honorable profession, combining patriotism and profit, in contrast to unlicensed piracy, which was universally reviled. Also called a Private Man of War   Compare to Pirate

Privileged Vessel - A vessel which, according to the applicable navigation rule, has right-of-way. This term has been superseded by the term "stand-on vessel"). See Right of Way

Proa or Prau - a vessel consisting of two, usually unequal length, parallel hulls or a hull (Vaka) and outrigger (Ama), sailed so that the same ballasted hull is always kept to windward, and the other always to leeward, so that it needs to reverse direction or (shunt) when tacking. Traditional Proas of the South Pacific use a Crab Claw sail and for centuries were probably the fastest sailing vessels.

Profile - in a lines plan, the side view of a hull; also called the sheer plan or elevation

Propeller - a type of fan that transforms rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, thus "propelling" the vessel. It acts like a screw rotating in water and is sometimes called a vessel's screw.

Propeller Shaft - a rotating rod that attaches the engine to the propeller, thus driving the propeller

Propeller Strut - a support located just forward of the propeller and extending off the hull of a vessel to add support to the propeller shaft.

Propeller Walk or Prop Walk - tendency for a propeller to push the stern slowly sideways; on a right hand (clockwise rotating as viewed from the rear) propeller, to starboard. A right hand propeller in reverse will walk the stern to port

Prop Wash - the turbulent water pushed by the propeller of a propeller driven vessel that shows up as a trail of bubbles and rough water within the vessel's wake

Protractor - an instrument for measuring angles on a surface; an angular scale

Prow - the Bow of a vessel

Psychrometer - an instrument consisting of suitably mounted dry-bulb and wet-bulb thermometers for determining relative humidity and dew point

Pulpit - a safety rail at the bow of a sailing vessel

Pump - to rapidly and repeatedly sheet-in and sheet-out to increase a sailboard's or small sailboat's speed to get the board or hull planing on top of the water's surface instead of plowing through it

Purchase 1. a block, usually permanently attached.   2. (Mechanical Advantage) - a mechanical method of increasing an applied force. Disregarding the effects of friction, if a force of 100 pounds applied to a block & tackle or lever is magnified to a force of 400 pounds, the purchase or mechanical advantage or purchase is said to be four to one, or 4:1.

Pucker Line or Pucker String - a small line running through the tabling on the leech of a sail that can be tightened to reduce the fluttering of the trailing edge of the sail in certain conditions. Don't forget to loosen it when it is not needed!   It's real name is a Leech Cord.

Purser - the person who is buys, stores and sells all stores on board ships, including victuals, rum and tobacco. Originally a private merchant

Pushpit - nautical slang (if the pulpit is on the bow, the one in the stern must be the pushpit, right?) for that railing which encloses the stern of a sailing yacht; a stern pulpit.

Pusser - the Purser


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Quadrant - a double reflecting instrument for measureing angles up to 90°, primarily altitudes of celestial bodies. Similar to, and often mistaken for, a Sextant which only reads up to 60°.

Quarter - the sides of a vessel aft of amidships; i.e., port quarter or starboard quarter.   See General Shipboard Directions illustration.

Quarter Birth - a sleeping space, at the aft of a vessel and usually underneath the cockpit and to one side or the other, on a small sailing vessel

Quarterdeck - The aftermost deck of a warship. In the age of sail, the quarterdeck was the preserve of the ship's officers.

Quarter Knee - a horizontal triangular block of wood connecting a boat's side with the transom

Quartering Sea - waves coming onto a ship's quarter

Quay (Pronounced "Key") - a reinforced embankment, usually stonework or other solid mass, formed toward the sea, or at the side of a harbor, river, or other navigable water, for tying up to and loading and unloading vessels. Used loosely, a wharf.

Queen Topsail - a small staysail located between the foremast and the mainmast


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Rabbet or Rebate - a groove cut in wood to form part of a joint. The main rabbet on a vessel is the groove cut in the backbone for the ends of the planks to fit into.

Rabbet Line - a line representing the outer edge of a rabbet

Race Sail - a sailboard sail that has camber inducers on all of its battens that is designed for slalom and triangle races

Racing Rules of Sailing - the international standards used to control the rights of way of boats and the framework to which racing is conducted, called the International Yacht Racing Rules and created by the International Yacht Racing Union (IYRU) before 1996, and now, the Racing Rules of Sailing, created by the International Sailing Federation (ISAF).

Radar - acronym for RAdio Detection And Ranging. An electronic system designed to transmit radio signals and receive reflected images of those signals from a "target" in order to determine the bearing and distance to the "target"

Radar Reflector - a special fixture fitted to a vessel or incorporated into the design of certain aids to navigation to enhance their ability to reflect radar energy in order to be "seen" more easily by larger vessel's radar. In general, these fixtures will materially improve the visibility for use by vessels with radar

Radio Aid to Navigation - an aid to navigation transmitting information via radio waves

Radiobeacon - a radio transmitter that transmits from a fixed, known location, for the purpose of guidance or determining position by vessels with a radio direction finder (RDF)

Radio Bearing - the bearing of a radio transmitter in realtion to a receiver, as determined by use of a radio direction finder

Radio Direction Finder - radio receiving equipment which determines the direction of arrival of a signal by measuring the orientation of the wave front, using a loop antenna

Radio Horizon - the line at which direct rays from a transmitting antenna become tangent to the earth's surface. Beyond this point, line of sight radio transmissions cannot be received.

Radionavigation - electronic piloting; navigating by determining a vessel's course, position, and speed by onboard electronic devices and systems

RAF - Rotating Asymmetrical Foil - a fully battened sailboard sail whose battens run from the leech to the mast

Rail - 1. the top edge of the bullwark.   2. the edge of a sailboat or sailboard

Rafting - to tie two or more vessels together side by side at an anchorage or mooring

Raised Deck - a deck arrangement that is higher than the gunwales

Rake - 1. the lean of a vessel's mast fore or aft. Most sailboats have a slight rake toward the stern of the craft.   2. to lean the rig on a sailboard fore or aft, as in "Rake the sail back to close the gap." or "Rake the mast forward to turn downwind."

Range Dayboard - aids to navigation which are usually shore-mounted, and come in pairs to help the vessel operator maintain a straight and safe course within a navigable channel. They will usually have lights mounted above them for nighttime use. Each member of the pair is separated from the next in distance and elevation, with the one in front shorter than the one behind it. When the two appear to be vertically stacked, the vessel is on the range line. View a downloadable and printable US Coast Guard brochure about range dayboards, buoys and other aids to navigation.

Range Finder - an optical instrument used for determining the distance to another object

Range Lights - two lights associated to form a range (a line formed by the extension of a line connecting two charted points) which often, but not necessarily, indicates the channel centerline. The front range light is the lower of the two, and nearer to the mariner using the range. The rear light is higher and further from the mariner. View a downloadable and printable US Coast Guard brochure about range lights, buoys and other aids to navigation.

Range of Tides - the difference between the high of the high tide and the low of the low tide at a location in one day

Range of Visibility - the extreme distance an object or light can be seen from a given point

Rat Guard - a hinged metal disk or cone secured to a mooring line to prevent rats from climbing up the line and into the ship

Rat-tail Stopper - a line used to hold a mooring line while it is being secured to bitts

Ratchet Block - a block whose sheave turns only in one direction, making it easier to hold a line under tension

Ratline - any of the small ropes or lines that traverse the shrouds horizontally and serve as steps for going aloft.

Ratio of Ranges - the ratio of the ranges of high tides at two places. Helpful if you know the range at one of the locations and need to know the other.

Ratio of Rise - the ratio of the height of tide at two places. Helpful if you know the height at one of the locations and need to know the other.

Rattle - to create or secure ratlines to (shrouds)

RDF - See Radio Direction Finder

Reach - sailing with a beam wind. A point of sail from about 60° to about 160° off the wind. Reaching consists of "close reaching" (about 60° to 80°), "beam reaching" (about 80° to 120°) and "broad reaching" (about 120° to 160°)

Reaching Straps - two sets of footstraps on a long-board: 1.Front reaching straps are just behind the centerboard, at a 45-degree angle to the centerline. 2. Back reaching straps are on the centerline, near the stern.

Ready About - a sailing command indicating that the crew should prepare to come about

Reciprocal Direction - the direction precisely opposite another; differing by 180°

Reef - 1. to reduce the size of a sail by tying a portion of the sail to the boom or yard, or using Roller Reefing. 2. A strip or ridge of rocks, sand, or coral that rises to or near the surface of a body of water; a danger of running aground

Reef-Bands - Long pieces of rough canvas sewed horizontally across the sails at reefing points to give them additional strength

Reef Earring - a line tied to the cringle

Reef Hook - used to hold down the "new" Tack (at the reef point) when jiffy reefing the Mainsail. Simple Reef Hooks and Rams' Horn Reef Hooks are attached to the Boom, as near the Tack attachment as possible, and are either screwed to the Boom or are attached to the horizontal Gooseneck Pin.

Reefing Comb - a piece of hardwood that has holes drilled in it, aligned vertically below each leech reef cringle, attached horizontally to the side of the boom, to provide fair leads for the reef pendants

Reefing Cringle - a thimble attached to the boltrope on the forward and after edges and in line with the reefing lines. A small line (reefing pendant) is run through the reef cringle to assist in holding a reef to the boom.

Reefing Pendant - a small line reeved through a reefing cringle at either end a row of reefing points to secure the reefed sail atop the boom

Reefing Points - small lengths of cord, attached in horizontal rows, across a sail, used to secure the excess fabric when reefing a sail in heavy weather

Reef Knot or Square Knot - a simple binding knot, used to tie two ends of a single line together such that they will secure something; like a sail to a boom (reefing), or a bundle of small objects together. This knot should not be used to bend two lines together, as it can easily capsize or slip. The Reef Knot is one of the eight knots everyone should know.

Reeve (Reeves, Reeving, Reeved, Rove) - to pass (a rope or the like) through a hole, ring, cringle, block, fairlead, padeye, deadeye, etc.

Reference Station - a place for which independent daily predictions are given in the tide or tidal current, from which correspinding predictions are obtained for other stations by measn of differences or factors.   See Ratio of Ranges and Ratio of Rise

Refuses Stays - to repeatedly fail to get about when an attempt is made to go about. You may end up in irons, or, simply, fall back onto the old tack, necessitating wearing ship or wearing about.   Compare to In Irons, In Stays and Miss Stays.

Regatta - a series of sailing races

Registration - licensing and numbering of a vessel

Relative Bearing - a bearing to an object in relation to the bow of the ship. See also: Absolute Bearing, Magnetic Bearing, True Bearing, and Bearing

Relative Humidity - the amount of water vapor in the air. It is defined as the ratio of the partial pressure of water vapor in the air-water mixture to the maximum saturated vapor pressure of water at those conditions. The relative humidity of air depends not only on temperature but also on air pressure.

Relief Map - a terrain map showing differences in elevation of points on the map, represented as contour lines where all points on a line are at the same elevation

Repeater - a device for repeating at a distance, the indications of an instrument or device in order for those indications to be received at greater distances

Reverse Sheer - gunwales that rises near the middle of the vessel instead of dropping in relation to the ends

Rhumb line - a straight line compass course between two points

Rib - another word for frame, the transverse members of a wooden hulled vessel to which the planks are fastened

Ribband - in boat building, fore-and-aft running strips of wood temporarily attached to the molds to hold the frames in place as they are bent or placed into the hull

R.I.B. or RIB - Rigid Inflatable Boat - a small boat with a hard, pre-formed V-shaped underwater hull and inflatable tubes that form the abovewater portion of the hull.   Compare to Inflatable Boat on this page

Ride the Fin - to raise the windward rail in high wind so that the only part of the sailboard that is in the water is the fin

Riders - a second layer of turns wrapped over a seizing or whipping.   Also called "riding turns"

Riding Light - a white light displayed by a boat or ship at anchor. Two such lights are displayed by a ship over 150 feet (46 m) in length, Also called an "anchor light."

Riding Turns - a second layer of turns wrapped over a seizing or whipping.   Also called "riders"

Rig - 1. on a sailboard, the sail, mast, and boom (essentially, everything but the board)   2.to assemble the sail, mast, and boom on a sailboard   3. the general arrangement of a vessel's masts, lines, and sails

Illustrations of Sailing Rigs at Transitioning.com.       See Types of Sailboats and Ships and Sails on this page.
Also see individual listings of each of the following for more information.
  • Fore-and-Aft Rigged - sails that run approximately parallel to a line from the bow to the stern when sheeted in
  • Square Rigged - sails hung from yards that are attached to the mast in the middle, thus, the yards hang at approximately right angles to the masts and the sails have equal portions hanging on each side of the mast, not all on one side. The yards and sails, however, can be rotated around the masts to trim them for upwind sailing, but do not sail well high on the wind.
  • Una Rig - a triangular sail set behind the mast, without foresail, and frequently without stays or shrouds. This rig is used on many small sailboats. With a wishbone boom, this is the rig of a sailboard.
  • Sprit Rig - a "sprit" or spar leading from the lower part of the mast to the peak of the quadrilateral mainsail, and flying a jib
  • Lateen Rig - an isosceles triangular sail set on a long yard mounted at an angle on the mast, and running in a fore-and-aft direction. The angled yard allows the head of the sail to be well above the height of the mast and a modern modification is to add a boom to the foot of the sail. The lateen sail pivots around the mast and will have a bad tack.
  • Gaff Rig - a quadrilateral sail hung from a gaff
  • Gunter Rig - a triangular sail hung from a yard that slides up a shortened mast and raises to vertical, allowing the peak of the sail to be much higher than the mast. This is similar to a Gaff Rig, but the yard raises all the way to vertical. This rig is very convenient on small boats because it allows the whole rig to be unstepped at the mast and laid down in the boat for storage. Once the sail is raised, it looks and performs much like the triangular Marconi Rig. If using a boom, it is, however, rather difficult to reef the sail.
  • Marconi Rig - a with triangular mainsail on a tall mast, usually, but not always using a boom. At some point, spreaders started being used on the masts, and someone thought the rig resembled Guglielmo Marconi's radio towers; thus Marconi Rig.
  • Bermudan Rig - add a foresail jib to a Marconi Rig and you have the modern Bermuda Rig so frequently used on today's Knockabouts, Sloops, Ketches, Yawls and Schooners; although the Bermuda Rig has changed significantly since its first use in Bermudan waters in the 17th century.
  • Mast Aft Rig - a sailboat sail-plan that uses a single mast set in the aft half of the hull to support a very large jib or multiple staysails, with either a small or completely absent mainsail. Mast aft rigs are uncommon, but are found on a few production sailboats.
  • Lug Rig - a vessel setting lugsails and perhaps lug topsails
See the Rig of a Sloop, Cutter, Yawl, Ketch, Schooner, Brig, Barquentine, Barque, Bragana or Felluca, Polacre, Junk and Full Rigged Ship.   Link opens a new window.

Rigging - the system of ropes, chains, tackle and other hardware used to support and control the masts, sails, and yards of a ship.

  • Standing rigging includes the masts, booms, gaffs, sprits, yards, turnbuckles, blocks, deadeyes, chainplates, padeyes, tangs, etc., and support lines: shrouds, shroud whip, fore and back stays, martingale or bobstay, backstay, bridle, etc.
  • Running rigging includes the winches, turning blocks, fairleads, etc., and lines with which you adjust the sails: halyards, sheets, tacklines, gunter lines, topping lifts, boom vang or kicking lift, traveler, outhaul, downhaul, snotter, reefing pendants, reef earrings. Cunningham, guy, foreguy, barberhauler, preventer, twings, sail stop, bridle, reefing lines, lifts, brails, braces, buntlines, clew lines, leech lines, tricing lines, gasket, robands, etc.

Right-Hand Lay - the twist of a stranded rope with the strands turning to the right. This is the most commonly used lay, referred to as "Z-Twist"

Right-Handed Propeller - a propeller whose blades, when in forward gear and viewed from the rear, turn clockwise. Most outboard and single-engine inboard vessels have right-handed propellers. Most twin-engine vessels have a right-handed propeller on the starboard side and a left-handed propeller on the port side so that the prop-walk of the two engines negate each other.

Click on IMAGE to open in new window and enlarge.
RIGHT OF WAY
YOU MUST GIVE RIGHT OF WAY TO VESSELS IN BLACK DANGER ZONE
An illustration showing when YOUR vessel must GIVE Right of Way when approaching another vessel

Right of Way - the right to continue on a current course without changing direction or speed. "Right of Way" is GIVEN TO the "Privileged" or "Stand On" Vessel BY the "Burdened" or "Give Way" Vessel.

  • 1. A moving vessel must stay clear of a motionless vessel.
  • 2. When approaching another vessel head on both vessels should steer to starboard in order to pass port side to port side.
  • 3. When you are overtaking and passing another vessel, you have no Right of Way. The other vessel should continue on its current course and speed and you must make adjustments in order to pass them at a safe distance.
  • 4. When another vessel is in your Danger Zone, YOU MUST Give Way (Yield Right of Way) to him by adjusting YOUR speed and/or course in order to let him pass you without having to change his course or speed.
  • 5. Vessels under sail have the Right of Way over all motor vessels except when the sailing vessel is overtaking the motorcraft or if the other vessel is a commercial or fishing vessel, or if the other vessel is a large, unmaneuverable boat like a cruise ship, freighter, tug boat towing barges, ferryboats, etc.
     The Rights of Way between two sailing vessels are determined by the direction of the wind in reference to the boats' sailing directions.
     (On a sailboard, you are on a Port tack if your Port (Left) hand is your front hand.)
  • 1. A sailing vessel that is running free should steer clear of the one which is close-hauled.
  • 2. A sailing vessel that is close-hauled on the port tack must keep out of the way of a vessel that is close-hauled on the starboard tack.
  • 3. If both vessels are running with the wind on different sides, the one which has the wind on the port side shall yield to the other.
  • 4. If both vessels are running with the wind on the same side, the vessel to windward shall yield to the vessel to leeward.
  • 5. A sailing vessel having the wind aft shall keep out of the way or other sailing craft.
  • 6. Any vessel that is required to yield Right of Way (the Burdened Vessel) must avoid passing in front of the other craft (the Privileged Vessel) or forcing the other vessel to change course or speed, if circumstances permit.
      For a downloadable and printable US Coast Guard brochure on Rules of the Road and aids to navigation Click Here

     Remember, just because your under sail on a sailboard, doesn't mean that others know the right of way rules and are going to yield to you. That powerboat captain could be drunk or just plain ignorant and his boat can crush you and slice you to pieces. If he doesn't appear to be Giving Way, get the hell out of the way. It's YOUR LIFE on the line. Don't be DEAD just because he's dead wrong.

Righting couple - the force which tends to restore a ship to equilibrium once a heel has altered the relationship between her center of buoyancy and her center of gravity

Rigid Inflatable or Rigid Inflatable Boat - a boat with inflatable tubes at the gunwales and with a hard or rigid floor or hull, like that of some small Zodiak dive boats and, now, other much larger power boats used for many purposes

Rigol - the rim or "eyebrow" above a port-hole or scuttle for the purpose of keeping water from draining down across the portal itself

Risers - the fore-and-aft strip fastened inside of frames to support the thwarts

Roach - an arc of extra material on the leech of a sail, outside a straight line drawn from the head to the clew

Road - a partly sheltered area of water near a shore in which vessels may ride at anchor. Not to be confused with "Rode."

Roaring Forties - the name given to strong westerly winds found in the Southern Hemisphere, generally between the latitudes of 40 and 50 degrees. Air displaced from the Equator towards the South Pole, which travels close to the surface between the latitudes of 30 and 60 degrees south, combines with the earth's rotation to cause west-to-east air currents. Because there is little land mass below the 40th parallel south, greater wind speeds are able to build than in the same region of the Northern Hemisphere that contains significant land masses.
     The Roaring Forties was a major aid to trade ships sailing from Europe to the East Indies or Australasia during the Age of Sail, and in modern usage is favoured by yachtsmen on round-the-world voyages and competitions. The location of the Roaring Forties is not consistent, and shifts north or south depending on the season. Similar, but stronger, conditions occur in more southerly latitudes, and are referred to as the Furious Fifties and Shrieking or Screaming Sixties.   See the illustration at Prevailing Winds of the World

Roband - a short piece of line, used to secure something to a yard, gaff, mast, bending jackstay, or mast hoops

Rocker - 1. a convex, fore-and-aft curvature in the keel or bottom of the hull of a vessel   2. Curvature of the bottom of a sailboard from fore to aft. Amount of rocker helps determine quickness to plane, speed, turning radius, and smoothness of ride.

Rode - the line and chain that connect the anchor to the boat. Not to be confused with "Road."

Roll - a vessel's motion rotating from side to side, about the fore-aft axis. Compare to Pitch, Headway, Sternway, Yaw, Leeway, Drift, Surge, and Heave

Roller Furling - a mechanical method of either fully or partially furling and unfurling a sail where the stay that supports the sail rotates to roll the sail around itself

Roller Reefing - a mechanical method of either fully or partially reefing and unreefing a sail where the spar that supports the sail rotates to roll the sail around itself

Rolling-tackle - a number of pulleys, engaged to confine the yard to the weather side of the mast. This tackle is much used in a rough sea.

Roll Tack - a small vessel tack where the crew uses their weight aggressively to windward to "roll" the boat to windward when initiating the tack to make the boom shift and the turn quicker

Rope - See Line

Round Up - to turn into the wind far enough to luff your sails

Rove - A past tense and a past participle of reeve.   2. a copper washer upon which the end of a copper nail is clinched in boat building.

Row - to propel a vessel with oars. A boatman does not "oar a boat;" he rows it.

Rowlock - a notch, U-shaped fork, or ring that attaches an oar to the gunwale of a boat and acts as a fulcrum for the oar. Called an Oarlock in the U.S.A.

Royal Mast - a section of mast above the Top-Gallant Mast, which is above the Topmast, which is above the Mast

Rubbing Strake - An extra plank fitted to the outside of the hull, usually at deck level, to protect the topsides from collisions and bumps against piers or other boats. Also called "Rub Rail" or "Sheer Guard"

Rub Rail - Same as "Rubbing Strake"

Rudder - the vertical blade at the stern of the boat that turns the boat by defection of water passing it.

Rules of the Road - maritime laws that provide guidance on how to avoid collision and are also used to assign blame when a collision does occur.   Also see Right of Way

  • There are four major sets of rules in the United States of America:
    • International Rules of the Road - established by agreement of the maritime nations to govern the navigation of vessels on the high seas to prevent collisions
    • Inland Rules of the Road - enacted by Congress to govern the navigation of the inland waterways of the United States
    • Pilot Rules of the Road - enacted by Congress to prevent collisions upon certain harbors, rivers, and inland waters of the United States and supplement the Inland Rules
    • International Yacht Racing Rules - a set of rules that are for organized racing only.
Also see "Right of Way"       For a downloadable and printable US Coast Guard brochure on Rules of the Road and aids to navigation Click Here

Rumb Line - the straight-line course between two points. On a reach or run, the rumb line is the shortest distance and it is fastest to sail this course whenever possible.

Rummage Sale - a sale of damaged cargo (from French arrimage)

Running - a point of sail, going directly or almost directly downwind. On a sailboat, the jib and the mainsail should be set on opposite sides. (Wing on Wing) See "Points of Sail"

Running Backstay - Also called Runner, or Preventive backstay. A stay that supports the mast from aft, usually from the quarter rather than the stern. When the boat is sailing downwind, the runner on the leeward side of the mainsail must be released so as not to interfere with the sail.

Running Fix - a navigational fix obtained by using a line of position (LOP) taken at or near the current time together with another, earlier LOP that has been advanced for the movement of the vessel between these two times

Running Lights - lights on an underway vessel that are required to be on and shown between sundown and sunrise. These usually consist of a red light to port and a green light to starboard and one or more white lights in various configurations. The differences in the configurations allow a person viewing them to identify not only the general type of vessel, but its direction of travel at a glance.

Running Rigging - lines and hardware use to CONTROL the sails. Running rigging includes the winches, turning blocks, fairleads, etc., and lines with which you adjust the sails: halyards, sheets, clew lines, tacklines, gunter lines, topping lifts, boom vang or kicking lift, traveler, outhaul, downhaul, snotter, reefing pendants, reef earrings. Cunningham, guy, foreguy, barberhauler, preventer, twings, sail stop, bridle, reefing lines, lifts, brails, buntlines, tricing lines, gasket, robands, etc.   Compare to Standing Rigging

Running Spring Line - a docking line that is controlled from the vessel and used to position it as you leave the slip or mooring


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S     (TOP OF PAGE)     (Sailboard Diagram)     (Sailboat Diagram)     (Warship Diagram)

Saffir-Simpson Hurricane Scale
Category Wind Speed Storm Surge
mph
(km/h)
ft
(m)
5 ≥156
(≥250)
>18
(>5.5)
4 131-155
(210-249)
13-18
(4.0-5.5)
3 111-130
(178-209)
9-12
(2.7-3.7)
2 96-110
(154-177)
6-8
(1.8-2.4)
1 74-95
(119-153)
4-5
(1.2-1.5)
Additional classifications
Tropical
Storm
39-73
(63-117)
0-3
(0-0.9)
Tropical
Depression
0-38
(0-62)
0
(0)

Saffir-Simpson Hurricane Scale - a classification used for most Western Hemisphere tropical cyclones that exceed the intensities of tropical depressions and tropical storms, and thereby become hurricanes. The scale divides hurricanes into five categories distinguished by the intensities of their sustained winds. In order to be classified as a hurricane, a tropical cyclone must have maximum sustained winds of at least 74 mph (33 m/s; 64 kt; 119 km/h). The highest classification in the scale, Category 5, is reserved for storms with winds exceeding 155 mph (69 m/s; 136 kt; 250 km/h).       The classifications are intended primarily for use in measuring the potential damage and flooding a hurricane will cause upon landfall. Officially, the Saffir-Simpson Hurricane Scale is used only to describe hurricanes forming in the Atlantic Ocean and northern Pacific Ocean east of the International Date Line. For further information, see Saffir-Simpson Hurricane Scale at Wikipedia.

Sagging - a condition occurring when a trough of a wave is amidships, causing the hull to deflect so that the ends of the keel are HIGHER than the middle. The opposite of hogging.

Sail - fabric, plastic, or laminate air foils, supported by masts, booms, yards or stays that catch the wind's force and convert it to forward thrust to propel a vessel.   See also: Rig

Sails come in many shapes and sizes, and have different placements on sailing vessels. See Types of Ships for several sail configurations.

      On a Sailboard:
  • Soft Sail - a, usually older, Dacron or Mylar sailboard sail that has short battens in the roach or no battens at all
  • Camber Induced Sail - a sailboard sail that has one or more internal or external camber inducers to help properly shape the sail. Any of the following sailboard sails can have camber inducers, except as noted.
  • RAF - Rotating Asymmetrical Foil - a fully battened sailboard sail whose battens run from the leech to the mast
  • Race Sail - a sailboard sail that has camber inducers on all of its battens that is designed for slalom and triangular races
  • Wave Sail - an RAF sail that is designed with a high foot so that the foot won't get caught on waves while sailing in the surf. Wave sails usually do not have camber inducers.
      Sails for Sailing Boats and Ships
  • Mainsail - the largest sail on a vessel flown from the mainmast
  • Trysail - a small fore-and-aft triangular sail used in very high winds or in storms to maintain control, to avoid ship damage, and to keep the bow to the wind. It is hoisted abaft the mainmast (taking the place of the much larger mainsail) and is usually used best without the boom to avoid having the boom swinging in very strong winds and high seas.
  • Staysail or Stays'l - a sail that has one or two sides attached to a stay, that is, one of the ropes or wires that helps hold the mast in place; for instance a jib. Also the innermost jib on a cutter, schooner and many other rigs having two or more jibs is referred to simply as the staysail, and another of the jibs on such a rig is referred to simply as the jib.
    • Yankee - a fore-sail flying above and forward of the jib, usually seen on bowsprit vessels
    • Jib - a foresail, a triangle shaped sail forward of the mast that does not reach aft of the mast, as does a genoa
    • Storm Jib - a small triangular fore-and-aft staysail flown when winds are too high to fly larger jibs
    • Genoa - a large foresail that reaches aft past the mast and extends beyond the luff of the mainsail
    • Drifter - a type of Genoa that is used like an asymmetrical spinnaker
    • Screecher - essentially a large Genoa
    • Gennaker - a foresail larger than either a jib or a genoa, with much greater camber for generating larger amounts of lift when reaching. spinnakers are used when running, instead of gennakers or genoas, because when running, the mainsail blocks the wind of a gennaker or genoa
            The following have their heads attached to the stay but not their luffs.
      • Spinnaker - a large, symmetrical, light sail, attached to the forestay only at the top, used in downwind sailing and flown in front of the vessel only during a broad reach or running, usually using a spinnaker pole
      • Cruising Chute - a form of asymmetric spinnaker used by cruising yachts and designed for easy use when short handed. Two sheets are used, with the tack line eased by a foot or so before gybing. Alternatively only one sheet is used, with the sail snuffed before a gybe.
      • Kite - Another name for a Spinnaker
      • Tallboy Staysail - a narrow staysail carried between the spinnaker and the mainsail on racing yachts
      • Genoa Staysail - a staysail larger than a tallboy staysail carried inside the spinnaker when broad reaching
      • Bigboy Staysail - a staysail carried on the leeward side of the spinnaker. Also called a Shooter or Blooper.
      • Blooper - Same as Bigboy Staysail above
      • Shooter - Same as Bigboy Staysail above
  • Headsail - any sail set forward of the foremost mast. The most common headsails are the jib and its larger cousin the genoa, but there are a large number of others, such as the staysail.
  • Mizzen Sail - a sail set on the mizzen mast. This is just a placement, not a type of sail. It may be a spanker, lug, sprit, or triangular.
  • Jigger - the aft sail on the mizzen mast of a yawl or ketch
  • Spanker - On a racing or cruising yacht, a spanker is an additional headsail set beside and to windward of a spinnaker when running downwind. It is often of bright colors to match the particular spinnaker with which it is designed to be used, is relatively narrow, and is sometimes called a tallboy.
  • Tallboy -Another name for Spanker
  • Driver - flown from the mizzen gaff like a spanker, but smaller
  • Lateen Sail - an isosceles triangular sail set on a long yard mounted at an angle on the mast, and running in a fore-and-aft direction. The angled yard allows the head of the sail to be well above the height of the mast and a modern modification is to add a boom to the foot of the sail. The lateen sail pivots around the mast and will have a Bad Tack.
  • Lug Sail - a quadrilateral sail set on a yard, whose halyard is secured closer to one yardarm than the other, thus making the yard set with one end higher than the other and the sail fly fore-and-aft, and whose fore end of the yard is not attached to the mast; as in gaff rigged sails. A Lug sail will have a Bad Tack unless the short end of the yard is switched to the other side of the mast as the tack is made. This can be done on many of the rigs.
  • Spritsail - 1. a quadrilateral sail using a "sprit" or spar leading from the lower part of the mast to the peak. The tension on the sprit controls the tension on the head and the leech of the sail and the sprit is tied near the base of the mast with a Snotter to control that tension. A spritsail will have a Bad Tack.   2. A sail hung from the spritsail yard, under the bowsprit.
  • Crab Claw or Crabclaw - an isosceles triangular sail with, sometimes very curved, spars along upper and lower edges that are tied down at the bow, and switched from one end of the boat to the other when shunting (tacking) and have a shorter, sometimes very concave curved, leech. The upper spar or yard is attached to the mast, but the bottom spar is not and the crab claw pivots around the leading edge spar. The mast is mounted in the larger hull (Vaca) of a Proa or other, similar vessel.
  • Extra - a sail that is not part of the working sail plan. The most common extra is the spinnaker. Other extras include studding sails, the modern spanker (or tallboy), and some staysails and topsails.

      On Gaff Rigged Vessels the lowest sail on a mast is referred to simply by the mast name; from front to back: Foresail, Mainsail, Mizzen sail.

      Above the gaff rigged sails are the Topsails:
  • Gaff Topsail - a triangular sail set between the gaff and the top of the mast or topmast. These may be set above any or all of the gaff sails
  • Queen Topsail - a small staysail located between the foremast and the mainmast
  • Yard Topsail - similar to a gaff topsail, but extended higher by a small vertical yard
  • Jack-Yard Topsail or Club Topsail - has its lower edge (or foot) extended out beyond the end of the gaff with a short yard, called a "jack-yard". A jack-yard topsail may also have the previously mentioned vertical yard, although this makes for a very large topsail.
  • Square Topsail - a square-rigged sail, generally carried above the foresail when on boats with multiple masts. Gaff-rigged vessels carrying square tops are referred to as "square-topsail sloops", "square-topsail schooners", etc. Occasionally this is shortened to simply "topsail sloop" or "topsail schooner", although this term can apply to vessels carrying topsails of any kind.
  • Raffee - a square-rigged, but triangular shaped topsail; broadest side on top.
    Fisherman's Staysail or Gollywobbler
    Canadian Gaff Topsail Schooner
    "Maple Leaf"
    A beautiful, full color photograph of a sailing vessel, showing its square Fisherman's Staysail.
  • Fisherman's Staysail - a full, four sided fore-and-aft sail flown above the main staysail or foresail on a staysail or gaff topsail schooner. Also called a Gollywobbler.
      On a Full Rigged Ship, the lowest and normally largest sail on a mast is the Course sail of that mast, and is referred to simply by the mast name: Foresail, Mainsail, Mizzen, and Jigger sail.
      From the deck up, in ascending order, the sails are:
  • Course - Foresail, Mainsail, Mizzen, or Jigger
  • Topsail (Just above Course), often the largest sails on the ship and set first and taken down last, but large and hard to handle. For this reason, one large topsail was replaced with...
    • Lower Topsail, if fitted
    • Upper Topsail, if fitted
  • Topgallant sail, or
    • Lower Topgallant sail, if fitted
    • Upper Topgallant sail, if fitted
  • Royal sail, if fitted.
  • Skysail, if fitted.
  • Moonsail or Moonraker, if fitted. (Highest of all)
      Thus the sail second up the mizzen-mast is the "mizzen topsail", and the third sail up the fore-mast is the "fore topgallant sail".
      The division of a sail into upper and lower sails was a matter of practicality, since undivided sails were larger and, consequently, more difficult to handle. Larger sails necessitated hiring, and paying, a larger crew. Additionally, the great size of some late-19th and 20th century vessels meant that their correspondingly large sails would have been impossible to handle had they not been divided.
  • Jibs - are carried from the foremast, and have varying naming conventions.
  • Staysails - may be carried between any other mast and the one in front of it or from the foremast to the bowsprit. They are named after the mast from which the are hoisted, so for example a staysail hoisted to the top of the mizzen topgallant on a stay running (usually two sails down) to the main mast would be called the Mizzen Topgallant Staysail.
  • Studding Sails - (pronounced "stunsls") may be carried in light winds on either side of any or all of the square rigged sails except royals and skysails. They are named after the adjacent sail and the side of the vessel on which they are set, for example Main Topgallant Starboard Stu'ns'l.
  • Spankers - One or two are carried aft of the aftmost mast, if two they are called the Upper Spanker and Lower Spanker.
  • Driver - flown from the mizzen gaff like a spanker, but smaller
  • Gaff Sail - A fore-and-aft topsail carried above the spanker or the upper spanker, if one is carried.

Sailboard - a small, usually solid, watercraft that has no cockpit, has a single sail that rotates and pivots in all directions using a universal joint at the base of its mast and has a wishbone boom, a skeg at its stern and may have a centerboard or daggerboard.

Sail Flip - the motion of rotating the sailboard rig during a jibe so the opposite face of the sail fills with wind

Sailboats - are boats which are propelled primarily by means of sails, but many have small auxiliary motors or engines. It must be kept in mind that any sailboat under power of its auxiliary engine, whether under sail or not, is legally a powerboat and must, therefore, abide by the law as a power vessel would.

Sailing Chart - a small-scale nautical chart for offshore sailing

Sailing Directions - a descriptive book for the use of mariners, containing detailed information of coastal waters, harbor facilities, etc., of an area, particularly along coasts other than those of the United States

Sailing Free - Off the wind. Sailing with the sheets eased, on the desired course, without being close hauled

Sail Needle or Sailmaker's Needle - a heavy steel needle, triangular from point to midsection, then rounded to the eye; used in sailmaking

Sail Plan - a set of drawings showing the various combinations of sail proposed for a sailboat or ship; Working sails, Light Wind sails, and Storm sails.   Compare to Lines Plan   See Sail Plan at Wikipedia

Sail Stop - a light line for securing a furled sail to a boom; a gasket

Sail Track - either a rail or slot attached to the after side of a wooden mast or, perhaps, built into a metal mast, in or on which sliders, attached to the sail, travel when hoisting or lowering sails; used in lieu of mast hoops

Sailmaker's Palm - a stiff leather strap or partial glove that contains a metal thimble for pushing a sail needle through heavy sailcloth

Saint Elmo's Fire (also St. Elmo's Light) - an electrical weather phenomenon in which luminous plasma is created by a coronal discharge originating from a grounded object in an atmospheric electric field (such as those generated by thunderstorms or thunderstorms created by a volcanic explosion).
Approximately 1,000 - 30,000 volts per centimeter is required to induce St. Elmo's fire; however, this number is greatly dependent on the geometry of the object in question. Sharp points tend to require lower voltage levels to produce the same result because electric fields are more concentrated in areas of high curvature, thus discharges are more intense at the end of pointed objects. Saint Elmo's fire and normal sparks both can appear when high electrical voltage affects a gas. St. Elmo's fire is seen during thunderstorms when the ground or water below the storm is electrically charged, and there is high voltage in the air between the cloud and the ground. The voltage tears apart the air molecules and the gas begins to glow. St. Elmo's fire appears as a bright blue or violet glow, like fire in some circumstances, from tall, pointed structures such as lightning rods, masts and other rigging on ships, spires and chimneys, and on aircraft wings. Often accompanying the glow is a distinct hissing or buzzing sound.
Seeing St. Elmo's fire MAY be an indication that your vessel is about to be struck by lightning. Although this is a rare occurance, it is worth planning for in advance. If struck by lightning, shipmates should be checked for and treated for injuries. The hull should be checked for leaks, especially around the grounding plate. Electronics should be checked for proper operation and ship's compasses should be rechecked; as they may be re-magnetized.
St. Elmo's fire is named after St. Erasmus of Formiae (also called St. Elmo), the patron saint of sailors.

Sally Ship - a method of loosening a vessel that has run aground from the mud holding her fast. A grounded ship can sometimes be freed with little or no hull damage if she can be rocked out of her muddy predicament. To free her, the order is given to "sally ship". The crew gathers in a line along one side and then moves quickly from port to starboard and back and forth until the vessel begins to roll. Often the rolling brakes the mud's suction and she can be pulled free and gotten underway.

Saloon - The main cabin, usually below deck, in a small boat or yacht, where the crew live, eat, and, depending on the size of the boat, may also sleep. Compare to Cabin

Samson Post - 1. a single bitt on the deck at the bow of a boat   2. a strong vertical post used to support a ship's windlass and the heel of a ship's bowsprit

Satellite Navigation - position finding using radio transmissions from satellites with sophisticated online equipment or GPS (Global Positioning System) and using that information to navigate

Scale - 1. a series of marks or graduations at definite intervals.   2. the ratio between the linear dimensions of a chart, map, drawing, etc., and the actual dimensions represented

Scandalize - to reduce the area and efficiency of a sail by expedient means (slacking the peak and tricing up the tack, removing the sprit on a spritsail, etc.) without properly reefing, thus slowing boat speed

Scantlings - 1. a dressed timber or rolled metal member used as a framing member in a vessel.   2. the dimensions, in cross section, of a framing member   3. the dimensions of all structural parts such as frames, planks, and fastenings on a boat; commonly recorded on a boats construction plans

Scantling Length - a measure of the length of the structure of a ship; generally longer than waterline length and shorter than overall length

Scarf or Scarph - a joint made by overlapping and locking together the ends of two pieces of timber that are halved, notched, or cut away at a diagonal so that they will fit each other and form a lengthened beam of the same size at the junction as elsewhere.

Schooner - a multi-masted (two or more), fore-and-aft rigged vessel whose foremost mast is not taller than the main mast   Compare to other sailboat types

Scoop - the amount of upward curve of a sailboard at the bow

Scooping - a situation where, in high seas and when a sailboat is heeling significantly, as the bow plunges into a wave, the foot of the genoa is filled with water. This slows the vessel and may tear out seams or rip the sail. Time to switch to a smaller jib.

Scope Tables
Approximate Scope Needed for Various Conditions
  All Chain/ Snubber 1/2Rope/ 1/2Chain Short Chain
Short Day Stop--Light Weather 34 5
Overnight—Light Weather 4 5 6
Moderate Weather 6 7 8
HEAVY WEATHER 7 8 10

SAMPLE Scope Table for a Boat
Produce your own table
Water Depth at Anchor Plus Bow Height at High Tide
10 15 20 25 30
S
c
O
P
E
3 30 45 60 75 90
4 40 60 80 100120
5 50 75100 125 150
660 90 120 150180
770 105 140 175 210
880 120 200 250 240
9 90 135 180 225270
10 100150200 250 300
Do not reduce scope on either rode if anchored with two or more.

Scope - a proportional measure of the amount of rode let out realtive to the vertical distance from the anchor's bow roller to the bottom (depth of water at the anchor + freeboard). In fair weather and little current, a scope of about five times the depth of the water (5/1) should be used; more in heavier weather up to about 10/1. More scope increases the holding power of an anchor. These scopes will allow a nylon line with a boat-length of chain attached to the anchor to exert an almost horizontal pull on the anchor, which is important because most anchors break out of the ground if the angle of pull is higher than eight degrees from horizontal. Other factors to consider when determining the amount of scope to put out are: anchor type, anchor weight, bottom composition, chain size, length and weight, windage of the vessel, and current. Its a good idea to make a scope table for your boat and its characteristics, like the one to the lower right of this page.

Scotchman - a piece of iron with ring attached, seized to the shrouds

Scow - 1. A method of preparing an anchor for tripping by attaching an anchor cable to the crown and fixing to the ring by a light seizing (also known as becue). The seizing can be broken if the anchor becomes fouled.   2. A type of clinker dinghy, characteristically beamy and slow.

Screaming Sixties - the name given to strong westerly winds found in the Southern Hemisphere generally between the latitudes of 60 and 70 degrees. Air displaced from the Equator towards the South Pole, which travels close to the surface, combines with the earth's rotation to cause west-to-east air currents. Because there is little land mass below the 40th parallel south, greater wind speeds are able to build than in the same region of the Northern Hemisphere that contains significant land masses.
      Similar, but typically weaker, conditions occur in slightly more northern latitudes, and are referred to as the Roaring Forties and the Furious Fifties.   See illustration at Prevailing Winds of the World

Screw - a propeller

Scrimshaw - carving or etching done on bones, teeth, tusks, shells, etc., by sailors on long voyages

Scud - a term applied to a the lowest clouds, which are mostly observed in squally weather

Scudding - a term applied to a vessel when carried furiously along by a tempest

Scull - to move the rudder or steering oar back and forth off the stern in an attempt to move the boat forward. The wrists should be rolled as a sculling oar is swept from side to side so as to always have the same side of the blade pushing water.

Scuppers - originally, a series of pipes fitted through the ships side from inside the thicker deck waterway to the topside planking to drain water overboard, larger quantities drained through freeing ports, which were hinged openings in the bulwarks. Now, sometimes, merely openings in the toe rail or bulwark to let water escape from the weather deck

Scurvey - a disease historically common to seamen caused by the lack of vitamin C on long voyages

Scuttle - 1. a small hatch or port with a cover, or the lid thereof, in a ship's deck or hull.   2. To deliberately sink a vessel by opening seacocks or making holes in the hull.

Scuttlebutt or Scuttled Butt - 1. a barrel with a hole in its top end, used to hold fresh water that sailors would drink from.   2. conversation and rumors heard around the scuttlebutt

Sea Anchor - an anchor used to stabilize a boat in heavy weather or slow a boats movement, anchors not to the sea floor but to the water itself, as a kind of brake. Sea anchors are known by a number of names, such as drift anchor, drift sock, para-anchor, drogues, and boat brakes. Modern commercial sea anchors are usually made of cloth, shaped like a parachute or cone, and rigged so that the larger end is closest to the vessel. When deployed, this type of sea anchor floats just under the surface, and the water moving through the sea anchor keeps it filled and creates drag.

Seaboots - high waterproof boots for use in foul weather at sea

Sea Breezes - warm air drawn ashore by rising thermal air currents due to heating of a land mass

Sea Chest - A watertight box, built against the hull of the ship and open to the sea through a grating, to which valves and piping are attached to allow water in for ballast, engine cooling, and firefighting purposes

Seacock - a valve that opens and closes the through-hull openings on the head, sinks, bilge, engine, etc. Opening any of these valves at sea MAY flood and sink the vessel.

Seakindly - a term related to a vessel's hull mean that she handles well and easily in heavy seas and weather, moving through the water smoothly without undue motion or strain

Sea Lane - a regularly used route for ocean-going vessels while at sea. In the time of sailing ships they were not only determined by the distribution of land masses but also the prevailing winds, whose discovery was crucial for the success of long voyages. They are very important for trade by sea and as a result were popular places for pirates. In World War I as German U-boats began hitting American and British shipping, the Allied trade vessels began to move out of the sea lanes to be escorted by Naval ships.

Sea Level - a plane corresponding to the ocean's surface. Sea level at a particular location changes regularly with the tides and irregularly due to conditions such as wind and currents, temperatures, etc., so also see Mean Sea Level

Sea Room - a safe distance from shore or other objects, as "Let's give the ship some 'Sea Room'

Seams - the spaces between planks of a vessel

Seat Locker - a storage locker located under a cockpit or cabin seat

Seaworthy - certified for, and capable of, safely sailing at sea

Sections - in a lines plan, the contour lines that represent the vertical, athwartships slices through the hull

Secure - to make something fast or safe

Sécurité - a call indicating a message about important safety information will follow. This word should be repeated three times. For more information see: Sécurité at Wikipedia   Compare to Mayday and Pan Pan

Seiche pronounced "saysh" - an unusual, rhythmic oscillation of water in a lake or a partially enclosed coastal inlet, such as a bay, gulf, or harbour. A seiche may last from a few minutes to several hours or for as long as two days and is caused caused by wind, earthquakes, changes in barometric pressure, seismic or atmospheric disturbances, etc.

Self-bailing Cockpit - a cockpit with scuppers, drains, or bailers that allow water to drain to the outside of the vessel

Self Righting - the ability of a vessel to return itself to vertical after capsizing due to large amounts of ballast in the keel

Self-tacking - a sail that requires no adjustment other than sheeting when the boat is tacked

Seize - to bind two lines together or a line to another object, by rapping with light line.   See Knot

Semaphore Flags - a pair of hand-held flags or paddles that when held in varying positions represent the alphabet and are use to communicate by line of sight from vessel to vessel.   Compare to International Maritime Signal Flags, Wig Wag, and Signal Lamp

Semidiurnal - having a period of, occurring in, or related to approximately half a day

Semidiurnal Current - tidal currents having two flood currents and two ebb currents each tidal day

Semidiurnal Tide - tides having two high tides and two low tides each tidal day

Sennit or Sennet or Sinnet - hand braided cordage, usually in a symmetrical fashion.

Sentinel - a weight or small anchor suspended from the anchor rode to help keep the pull on the anchor as horizontal as possible to prevent dragging in foul weather

Separator - a component of a diesel fuel system that separates water from your fuel

Serve - See Worm, Serve, and Parcel on this page. Compare to other Knots on this page

Set - the direction toward which a current is flowing

Set Flying - to unfurl and hoist a spinnaker

Set Sail - 1. to start a sea voyage   2. to adjust the sail of a watercraft to fill with wind to get underway

Sextant - a navigational instrument invented in 1757 and used as the primary device to measure a ship's latitude and longitude for more than 200 years; until being mostly replaced by the Global Positioning System. For more information and brief instruction on usage, click here.

Nomenclature of a Marine Sextant Using a Marine Sextant
An illustration showing the parts of a marine sextant. A beautiful, full color illustration showing how to use a sextant properly.
Click Image to Enlarge in New Window Click Image to Enlarge in New Window
Copyright 2006 Joaquim Alves Gaspar Copyright 2007 Joaquim Alves Gaspar

Shackle - a U-shaped connector with a pin or bolt across the open end called the shackle pin

Types:

  • Pin shackle

    A pin shackle is closed with a clevis pin. Primarily used above the deck, pin shackles used to be the most common shackle used aboard boats. Pin shackles can be inconvenient to work with at times because they are secured using something else, usually a cotter pin or seizing wire.

    A Threaded Shackle
    A threaded brass shackle
  • Threaded shackle

    The pin is threaded and one leg of the shackle is tapped. The pin may be captive, which means its mated to the shackle, usually with a wire. The threads may gall if over-tightened or have been corroding in salty air, so a liberal coating of lanolin or a heavy grease is not out of place on any and all threads. A shackle key or metal marlinspike are useful tools for loosening a tight nut.
    For safety, it is common to mouse a threaded shackle to keep the pin from coming loose. This is done by looping mousing wire through the hole in the pin and around the shackle body. For pins that have a cross-hole in the threaded end a cotter pin can be used. One disadvantage is that mousing can introduce galvanic corrosion because of material differences; it is especially bad when used in places where the shackle is exposes to air and water.

    A Snap Shackle
    A snap shackle
  • Snap shackle

    As the name implies, a snap shackle is a fast action fastener which can be implemented single handed. It uses a spring activated locking mechanism to close a hinged shackle, and can be unfastened under load. This is a potential safety hazard, but can also be extremely useful at times. The snap shackle is not as secure as any other form of shackle, but can come in handy for temporary uses or in situations which must be moved or replaced often, such as a sailor's harness tether or to attach spinnaker sheets. Note: When this type of shackle is used to release a significant load, it will work rather poorly (hard to release) and is likely to have the pin assembly or the split ring fail.

  • Bow shackle

    A Bow or Anchor Shackle
    A threaded bow or anchor shackle
    With a larger "O" shape to the loop, this shackle can take loads from many directions without developing as much side load. However, the larger shape to the loop does reduce its overall strength. Also referred to as an anchor shackle.

  • D-shackle

    Also known as a chain shackle, D-shackles are narrow shackles shaped like a loop of chain, usually with a pin or threaded pin closure. D-shackles are very common and most other shackle types are a variation of the D-shackle. The small loop can take high loads primarily in line. Side and racking loads may twist or bend a D-shackle.

  • Headboard shackle

    This longer version of a D-shackle is used to attach halyards to sails, especially sails fitted with a headboard such as on Bermuda rigged boats. Headboard shackles are often stamped from flat strap stainless steel, and feature an additional pin between the top of the loop and the bottom so the headboard does not chafe the spliced eye of the halyard.

    A Twisted Shackle with Clevis Pin
    A twisted shackle with Clevis Pin
  • Twist shackle

    A twist shackle is usually somewhat longer than the average, and features a 90° twist so the top of the loop is perpendicular to the pin. One of the uses for this shackle include attaching the jib halyard block to the mast, or the jib halyard to the sail, to reduce twist on the luff and allow the sail to set better.

Shaft Log - a timber that forms part of a wood boat's keel or deadwood section, and which is bored lengthwise to take a propeller shaft.

Shake out - to release a reefed sail and hoist the sail aloft

Sheave (pronounced as "Shiv") - the wheel of a block pulley

Sheer - the downward and upward curve of a boats deck from midships to bow and stern, as viewed from the side. Normal sheer curves up towards the bow and stern. Reverse sheer curves down towards the bow and stern. Compound sheer, curving up at the front of the boat and down at the stern, and straight sheer are uncommon.

Sheer Clamp - a fore-and-aft timber, fastened over the inboard side of the frames, that runs along or just below the hull's sheer line; often simply called the "clamp".

Sheer Guard - An extra plank fitted to the outside of the hull, usually at deck level, to protect the topsides from collisions and bumps against piers or other boats. Also called "Rub Rail" or "Rubbing Strake"

Sheer Line - Same as "sheer". The downward and upward curve of a boats deck from midships to bow and stern, as viewed from the side. Normal sheer curves up towards the bow and stern. Reverse sheer curves down towards the bow and stern. Compound sheer, curving up at the front of the boat and down at the stern, and straight sheer are uncommon.

Sheer Off - 1. to separate from other ships by changing course.   2. to shove off

Sheer Strake - the top plank, under the gunwale, of the topsides

Sheet - 1. a line attached to the boom or clew of a fore and aft rigged sail used to control the angle of the sail in relation to the wind.   2. Square sails have sheets attached to their clews like triangular sails, but the sheets are used to pull the sail down to the yard below rather than to adjust the angle it makes with the wind. Sails hang from a yard on a square rigger and it is swung about to alter its angle to the wind with its braces. The lowest sails, courses, are trimmed using the sheets as these sails are loose footed being secured to yards only at the head.

Sheet In - 1. to tighten a sheet, thus flattening a sail. 2. In sailboarding, to pull the boom toward the body with the aft hand while holding the fore end stationary.

Sheet Bend or Becket Bend or Weaver's Knot - a simple bend used to tie two lines together, identical in structure to the bowline, except it is ties two lines together instead of tying a loop in one line. The Sheet Bend is one of the eight most useful knots a sailor needs to know.

Sheet Out - 1. to slacken a sheet, letting a sail billow more. 2. In sailboarding, to extend the aft portion of the boom further away from the sailors body while holding the fore hand stationary.

Shell - a long, slender, light rowing vessel with sliding seats, long oars, and riggers on the gunwales that move the oarlocks beyond the gunwales, used in rowing competitions. They usually hold from one to eight oarsmen; and if more than one, may have a coxswain to keep the rowers in rhythym, set the pace, and steer. There are two types of shells; sweep shells and sculling shells.

      Although sculling and sweep boats are generally identical to each other (except having different riggers), they are referred to using different names:
  • Sweep: straight pair (2-), coxed pair (2+), straight four (4-), coxed four (4+), eight (8+) (always coxed)
  • Sculling: single (1x), double (2x), quad (4x), octuple (8x) (very rare, and always coxed)

Ship - 1. to move or have an item move inboard; as "ship your oars" or "We were shipping water."   2. a large watercraft thought worthy of sailing the open seas. Strictly, a three-masted vessel square-rigged on all three masts, or on three masts of a vessel with more than three. Hence a ship rigged barque would be a four master, square rigged on fore, main and mizzen, with spanker and gaff topsail only on the Jigger-mast.   Compare to other sailboat types on this page Generally now used to describe most medium or large vessels outfitted with smaller boats. As a consequence of this submarines may be larger than small ships, but are called boats because they do not carry boats of their own.

Ship of the Line - a major warship capable of taking its place in the main (battle) line of fighting ships. They were rated by how many cannons and carronades they carried.

The Classification of the Ships-of-the-Line and other Warships:

Cannon and Carronades Carried
  • Ships-of-the-line:
    • 1st Rate - Ships with 100-130 guns - The cross section of the vessel in the illustration of the "Ship of War" at the top of the page is a 1st rate ship.
      Three-deckers, senior admiral flagships
    • 2nd Rate - Ships with 90-98 guns
      Three-deckers, junior admiral & foreign station flagships
    • 3rd Rate - Ships with 80 guns; powerful two-deckers - The top illustration of the "Ship of War" at the top of the page is a 3rd rate ship.
      Ships with 74 guns; two-decker "workhorses" of battle fleets, the most numerous type of ships of the line
      Ships with 64 guns; two-deckers, which were, however, being phased out by the end of the era

  • Warships that were not Ships-of-the-Line
    • 4th Rate - Ships with 44-50 guns
      Both single- and two-deckers, "razees" (double-decker ships of the line with the upper deck cut off, offering a sturdy hull and good armament, but retaining the dull sailing qualities of the original) or purpose-built heavy-armed frigates
    • 5th Rate - Ships with 32-40 guns
      The single-decked "standard" frigate
    • 6th Rate - Ships with less than 32 guns
Number of Bells Bell Pattern Hour
(a.m. and p.m.)
One bell 12:30 4:30 8:30
Two bells •• 1:00 5:00 9:00
Three bells •• • 1:30 5:30 9:30
Four bells •• •• 2:00 6:00 10:00
Five bells •• •• • 2:30 6:30 10:30
Six bells •• •• •• 3:00 7:00 11:00
Seven bells •• •• •• • 3:30 7:30 11:30
Eight bells •• •• •• •• 4:00 8:00 12:00

Ship's Bell - a brass or bronze bell onboard most medium to large vessels. The ship's bell is the traditional method of marking time, regulating the crew's watches and as a locating signal in low visibility conditions.   Unlike civil clock bells, the strikes of the bell do not correlate directly to the number of the hour. Instead, there are eight bells, one for each half-hour of a four-hour watch. In the age of sail, watches were timed with a thirty-minute hourglass. Bells would be struck every time the glass was turned, and in a pattern of pairs for easier counting, with any odd bells at the end of the sequence. The tradition of ringing the bell to mark time continues today on many vessels.

Ship's Log - the Deck Log

Ship Oars - 1. to remove the oars from the oarlocks and lay them in the boat.   2. the command to remove the oars from the oarlocks and lay them in the boat.

Ship Shape - everything's in good order

Shipworm - See Teredo Worm

Shipwright - a builder of ships. A boatwright builds smaller vessels.

Shiver - 1. (of a fore-and-aft sail) to shake when too close to the wind. To luff.   2. (of a sailing vessel) to be headed so close to the wind that the sails shake.

Shoal - Off-shore, shallow water that is a hazard to navigation

Shoal Draft - a vessel with shallow draft, so capable of sailing in unusually shallow water

Shock Chord - a rubber, elastic rope useful in limited rigging and stowage applications onboard a vessel; bungee chord

Shoot - to turn directly upwind in order to lose momentum or headway or to stop, as might be done in approaching a mooring. The distance that a vessel will shoot into the wind varies greatly, depending on the type of vessel and its displacement, the wind, and the waves. Most novice sailors tend to think that a sailboat will shoot further into the wind on a windy day than on a day with light breezes, but the opposite is true do to the resistance of the rigging to the wind and the stopping power of the waves on the windier day. Of course, a heavier vesser will shoot further than a lighter one, too.

Short Board - in general, a sailboard that is less than 10 feet in length

Shortie - a single piece wetsuit that has legs ending mid-thigh and has short sleeves

Shorten Sail - to lessen sail area set; drop, douse or strike sails

Short Splice - a method for interweaving the strands of rope or cable in order to join two lines in a short distance. A short splice increases the diameter of a line significantly and may jam going through a block.   See Knot on this page

Shot - 1. all sorts of missiles to be discharged from fire-arms, those for great guns being mainly of iron; for small-arms, of lead. When used without prefix, the term generally means the solid shot only, as fired for a heavy blow, or for penetration.   See also Grapeshot, Cannon Balls, Chilled Shot and Chain Shot.   2. a section of anchor chain for larger ships; usually 15 fathoms in length. Several shots make up its total rode. The order of the shots can be changed in order to even out the wear over time

Shrouds - support ropes or wires for the mast that run from the mast to chainplates at deck level on each side of the vessel to support the mast in its vertical position.

Shroud Whip - lines used to haul the shrouds taut

Shunting - the act of reversing the sailing direction of a double ender, like a proa, without turning the vessel around, thus the bow of the vessel becomes the stern and the stern becomes the bow; no tacking or jibing necessary.

Shutter - the last plank laid on the hull of a boat. It is usually located midway between the garboard strake and the sheer strake.

Sick Bay - the compartment on a vessel reserved for medical purposes

Side-Offshore - a wind blowing about 45 degrees in relation to the shoreline from the land to the water. It is the second most dangerous wind direction for sailboarding because if something goes wrong, you will be blown away from shore

Side-Onshore - a wind blowing about 45 degrees in relation to the shoreline from the water to the land. It is the most desirable wind direction for all-around sailboarding

Side-Shore - a wind blowing parallel to the shoreline. This is the most desirable wind direction for high wind sailboarding, enabling a sailor to sail straight away from shore and return to the same point on an opposite, but equal, tack.

Sideslip - to be pushed sideways through the water by the wind; to make leeway

Signal Lamp (also called an Aldis Lamp) - a visual signaling device using a bright light, fresnel lens, and shutters to make the light appear to turn on and off for Morse code dots and dashes. More powerful models could be used to signal to the horizon, even in conditions of bright sunlight or to illuminate cloud bases both during the night and day. This method could be used to communicate beyond the horizon. A maximum transmission speed using signal lamps is no more than 14 words per minute.   Compare to International Maritime Signal Flags, Wig Wag, and Semaphore Flags

Single Banked - a rowing arrangement where only one oarsman sits on a thwart, pulling one oar and alternate oars are on opposite sides of the boat

Sinker - a sailboard with too little volume or flotation to support the sailor and rig at slow speeds

Sinnet - See Sennit

Sisal - also called Sisal hemp, although it is not a hemp. A natural fiber yielded by an agave, Agave sisalana, of Yucatán, used for making rope, mats, etc. You don't see this fiber used on sailboats much any more. It is cheap, but absorbs water, and is not very strong in relation to newer synthetic fibers. Sisal withstands exposure to seawater very well. You may see large hawsers made of this fiber. See Line

Sister Hooks - two hooks suspended from a mutual link and facing in opposite directions such that they form an eye when in use

Skeg - 1. an extension aft of the keel that protects the propeller and may connect to the heel of the rudder. It helps the vessel maintain a straight course.   2. fin, a blade mounted on the bottom rear of a sailboard that produces lift and makes the board travel in a straight line

Skipper - The captain of a ship

Skysail - A sail set very high, above the royals. Only carried by a few ships

Skyscraper - A small, triangular sail, above the skysail. Used in light winds on a few ships

Slab line - a small line or rope by which seamen haul up the foot of the mainsail or foresail

Slab Reefing - a method of reducing the area of a sail where the luff is loosened, lowered to its reefing point and hooked, the leech is lowered to the boom and tightened via a leech reefing line, and fastened, but all the reefing points may not be tied. A very fast way to reef a sail. Also called "Jiffy Reefing."

Slack - to lessen tension on a line by letting it run out

Slack Tide - the short period of time between flood and ebb when there is no tidal current and the water is neither rising nor falling. Also called "Stand Tide."

Slalom Jibe (Gybe) - a sailboard jibe that involves carving the turn, flipping the sail, then moving the feet into position on the other side of the board; in that order

Slalom Sailboard - Shortboards aimed at top speed rather than maneuverability or ease of use. Designed primarily for sailing on a beam reach and carving jibes.

Slalom Race - a high speed race in a course shaped like a figure of eight. Most of the course goes on a beam reach with floating marks (buoys) that have to be jibed around.

Slides - if so equipped, the hardware that attaches the luff or foot of a sail to a track on the respective spar

Sliding Gunter Rig - See Gunter Rig.

Slip - 1. a narrow berth a boat rests in when attached to a dock, pilings, or pier   2. the difference between the theoretical and the actual distance a propeller moves in one rotation in water and under load, due to water resistance and the inertia of the vessel

Slip an Anchor - to let the bitter end of the anchor line run out or otherwise release the line in an emergency situation that does not allow time to weigh anchor

Slog or Schlog - in sailboarding, to sail at slow speed, out of the footstraps and not planing, when under powered. If of low volume, the sailboard may submerge or "submarine" and you need more sail or wind.

Sloop - See at Types of Sailboats on this page

Slop Chest - a ship's store of merchandise, such as clothing, tobacco, etc., maintained aboard merchant ships for sale to the crew

Slough - a stagnant swamp, marsh, bog, or pond, especially as part of a bayou, inlet, or backwater.

Slug - a fitting that is inserted into a groove in the mast or boom in order to attach the sail's luff or foot to its respective spar

Slush - greasy substance obtained by boiling or scraping the fat from empty salted meat storage barrels, or the floating fat residue after boiling the crew's meal. Used for greasing parts of the running rigging of the ship and therefore valuable to the master and bosun; and for greasing boots to waterproof them and therefore valuable to all on board. Thus; Slush Fund - The money obtained by the cook selling slush ashore. Used for the benefit of the crew or the cook.

Small Stuff - 1. any light twine, marline, small diameter cordage, yarn, string, etc., used aboard ship for serving, whipping, lacing, fancy knotting or ropework, etc.   2. Historically, rope under one inch in diameter

Snatch Block - See Block

Snotter - a rope eye attached to the mast of a sprit-rigged vessel, that holds the lower end of the sprit in position.

Snub - to quickly tension a line around a deck fitting or other object to make it quit slipping

Snow - a form of brig where the gaff spanker or driver is rigged on a "snow mast" a lighter spar supported in chocks close behind the main-mast

Snuffer - See Dousing Sock

Sock - See Dousing Sock

Soft Sail - a, usually older, Dacron or Mylar sailboard sail that has short battens or no battens at all

Sole - 1. a cabin or saloon floor.   2. wooden extensions on the bottom of the rudder.   3. the molded fiberglass decking of a cockpit

Sonar - A sound-based device used to detect, range, and identify underwater targets and obstacles by sending a sonic "Ping" out and receiving its echo back

SOS - These three letters, sent out via Morse code over wireless (radio) telegraph, whistle, horn, or signal lamp indicate the need to "Save Our Ship." The Morse code for this is: • • • — — — • • •   This is the same as a Mayday call and is an internationally recognized call for immediate assistance in a life-threatening situation.   Compare to Pan Pan and Sécurité

Sou'wester - 1. A storm from the south west.   2. A type of waterproof hat with a wide brim over the neck, worn in storms

Sound - 1. a relatively narrow passage of water between larger bodies of water or between the mainland and an island; i.e. Long Island Sound.   2. an inlet, arm, or recessed portion of the sea; i.e. Puget Sound.   3. the air bladder of a fish.   Verb: to use the lead and line (sounding line) or some other device for measuring depth   4. to go down or touch bottom, as a lead.   5. to plunge downward or dive, as a whale.

Sounding - measuring the depth of water. A vessel is "On Soundings" if the water is considered shallow enough to easily read the depth, and "Off Soundings" if the depth is considered too deep to easily read, or over about 100 fathoms. I'll be honest, 100 fathoms seems a little like overkill for a vessel that only has a 6 ft. draft, but I guess that, if you're in muddy water, it's better safe than sorry.

Sounding Line - a lead weighted line with measured markings used to determine the distance from the water's surface to the bottom of the body of water. It is thrown slightly ahead of the vessel, allowed to sink to the bottom, then the sailor that is "swinging the lead" reads the mark at the water's surface.   Compare to Depth Finder

Spanker - 1. On a square rigged ship, the spanker is a gaff rigged fore-and-aft sail set from and aft of the aftmost mast. Almost all square rigs with more than one mast have one or two spankers, which evolved from the driver sail. Some also carry a topsail above the uppermost or only spanker, called the gaff sail. A spanker in this situation is often 'soft footed' in that it has no boom to which it is attached at its foot.   2. On a racing or cruising yacht, a spanker is an additional headsail set beside and to windward of a spinnaker when running downwind. It is often of bright colors to match the particular spinnaker with which it is designed to be used, is relatively narrow, and is sometimes called a tallboy.

Spanker-mast - The aft-most mast of a fore-and-aft or gaff-rigged vessel such as schooners, barquentines, and barques. A full-rigged ship has a spanker sail but not a spanker-mast. Compare to Jigger-mast

Spar - a wooden, in later years also iron, aluminum, fiberglass, carbor fiber, kevlar, or steel pole used to support various pieces of rigging and sails. A general name for mast, yards, booms, spinnaker poles, sprits, gaffs, etc. on board a vessel.

Spillpipe - a hole in the deck for the anchor chain to pass through to the chain locker

Spindrift - finely-divided water swept from the crest of waves by strong winds

Spinnaker - a large, symmetrical, light, balloon-shaped sail, attached to the forestay only at the top, used in downwind sailing and flown in front of the vessel only during a broad reach or running, usually using a spinnaker pole. There are Symetrical and Asymetric Spinnakers.   For more information, see Spinnaker at Wikipedia.com

Spinnaker Chute - a through-the-deck tube or aperture sometimes used for launching and recovering the spinnaker. The spinnaker halyard is run through the chute and to the top of the mast in a continuous loop and the spinnaker is stored in the chute ready for deployment. The halyard is raised to deploy the spinnaker and lowered to pull the spinnaker into the chute to douse it.

Spinnaker Pole - a spar used in sailboats to hold the windward corner (tack) of a spinnaker away from the base of the mast in order to keep the spinnaker from collapsing. Spinnaker poles are often used on other sails, such as jibs, genoas, and gennakers, too, where a whisker pole is too light.

Spinnaker Sleeve - See Dousing Sock

Spinout or Spin Out - to suddenly have a sailboard start sliding sideways in high winds because of cavitation of the fin, a condition where air bubbles form along the windward side of the fin making it lose its ability to offer lateral resistance and propel the board forward

Splash Rail - on a small boat, a small coaming just ahead of the cockpit to keep water out of the cockpit

Splice - 1. to interweave the strands of a line to another line or to itself. 2. an interlaying of strands of rope to join another rope or to itself without tying a knot. Compare to "Bend"

Spoon Bow - a broadly rounded bow

Spreader Bar - 1. a bar with a hook attached to the harness, used to hook into the harness lines on the boom of a sailboard in order to take the weight off your arms and lower your center of gravity 2. a bar with a hook on it, used to attach a sailor's hiking harness to the hiking lines of a small sailboat or catamaran

Spreaders - struts used to hold the shrouds away from the mast and increase the angle at which they attach

Spring line - docking lines that keep the boat from drifting forward and back; leading from the bow to the aft and from the stern, forward. The extra length created by running the lines like this allow the vessel to raise and lower with the tides better than shorter lines would. The Forward Spring Line is attached near the bow of the vessel and runs aft to the pier and the After Spring Line is attached to the stern and runs forward to the pier.

Spring Stay - a horizontal stay running between the mastheads of a schooner that add fore-and-aft stability to the mainmast via the foremast and forestay and to the foremast via the mainmast and the backstay

Spring Tide - higher tides produced when the sun and moon are in close alignment, as at full or new moon, and their total effect greater.   Compare to Neap Tide

Sprit - 1. a spar leading from the lower part of the mast to the peak of the sail   Compare to Gaff and Yard   2. A type of sailboat. See at Types of Sailboats on this page

Spritsail - a quadrilateral sail with a spar leading from the lower part of the mast to the peak of the sail. The tension on the sprit controls the tension on the head and the leech of the sail and is tied near the base of the mast with a Snotter   2. A sail hung from the spritsail yard, under the bowsprit.   Compare to other sails on this page

Squall - a sudden, brief, violent wind often accompanied by rain

Squared Away - yards held rigidly perpendicular to their masts and parallel to the deck. This was rarely the best trim of the yards for efficiency in sailing, but made a pretty sight for inspections and in harbor. The term is applied to situations and to people figuratively to mean that all difficulties have been resolved or that the person is performing well and is mentally and physically prepared.

Square Rigged Sails - sails hung from yards that are attached to the mast in the middle, thus, the yards hang at approximately right angles to the masts and the sails have equal portions hanging on each side of the mast, not all on one side. The yards and sails, however, can be rotated around the masts to some extent, but do not sail well into the wind. Square rigged ships may also have one or more staysails or jibs and, perhaps, a spanker, which are Fore & Aft Rigged.   See the photographs and illustrations at the top of this page.
      Compared to a modern sloop, old fashioned square-riggers were very inefficient at beating to windward. They could sail no closer than 60° to the wind, as opposed to a sloop's 45°. Thus while a sloop sails only about 14 miles over the water to gain 10 miles to windward; a square rigged ship would have to sail close to 20 miles to reach the same goal. The square-riggers were so inefficient when beating that they often had to stay anchored in port for days waiting for a fair wind to get them out of a harbor and out to sea.
  Compare to Fore & Aft Rigged Sails

Square Rigger - a vessel with square rigged sails.   See above.

Square Knot - See Reef Knot

Squat Effect - the phenomenon by which a vessel moving quickly through shallow water creates an area of lowered pressure under its keel that reduces the ship's buoyancy, particularly at the bow. The reduced buoyancy causes the ship to "squat" lower in the water than would ordinarily be expected.

Snaking - netting stretched between the gunwales and footrope of the lifelines to prevent objects from going over the side

St. Elmo's Fire - See Saint Elmo's Fire

Stadimeter - a navigation instrument used to measure the distance to objects whose heights are known

Stanch or Staunch - a canal lock that, after being partially emptied, is opened suddenly to send a boat over a shallow place with a rush of water. Also called a, navigation weir, or flash-lock.

Stanchions - vertical posts that hold lifelines in place around the perimeter of a vessel or to support the bulwark planking and the rail

Standard Jibe (Gybe) - a sailboard jibe that initiated by carving the turn, followed by flipping the sail, then moving the feet onto the opposite side of the board. It may or may not be exited at planing speed.   See "Jibe"

Standing Block - that part of a block and tackle system which is attached to the unmoveable support and stays stationary while the opposite, Traveling Block moves. Also called the "Fled Block."   See Block

Standing End - the end of a line that you are NOT currently tying a knot in. It may be made fast or not.   See Knot on this page.

Standing Part - the inactive portion of a rope that is between the knot you are tying and the Standing End   See Knot on this page.

Standing Rigging - Lines and hardware used to SUPPORT the sails. These include the masts, booms, yards, gaffs, sprits, turnbuckles, blocks, deadeyes, chainplates, padeyes, tangs, etc., and support lines: shrouds, shroud whip, fore and back stays, martingale or bobstay, backstay bridle, etc.  Compare to Running Rigging

Stand Off - 1. to move away from another ship, or from the shore. 2. to tack back and forth offshore, out of reach of dangerous shallows, rocks, or perhaps, shore batteries.

Stand-On Vessel - the privileged vessel in a Right of Way situation that has the right of way and should hold course. See Right of Way

Stand Tide - the short period of time between flood and ebb when there is no tidal current and the water is neither rising nor falling. Also called "Slack Tide."

Starboard - the right side of the watercraft as viewed from the stern. Marked on vessels with a GREEN light at night.   See General Shipboard Directions illustration.

Starboard Tack - sailing with the wind coming from the starboard side. A vessel sailing on a starboard tach generally has right of way over a vessel on a port tack. On a sailboard, if your right hand is forward, you are on a starboard tack.

State Room - sleeping quarters for guests or Captain

Stations - in a lines plan and loftings, points marked off on the base line that correspond with the sections

Statute Mile - a measurement of distance on land. 5,280 U.S. Feet, 33/38 or .869 of a Nautical Mile

Stays - strong support wires running from the masthead to the bow (Headstay, Forestay, Jibstay) and stern (Backstay).

Staysail or Stays'l - a sail that has one or two sides attached to a stay, that is, one of the ropes or wires that helps hold the mast in place; for instance a jib. Also, the innermost jib on a cutter, schooner and many other rigs having two or more jibs is referred to simply as the staysail, and another of the jibs on such a rig is referred to simply as the jibs.   See also Sail on this page

Steadying Sail - a sail hoisted mainly to steady a ship against rolling, rather than for propulsion

Steamer - 1. a steamship   2. a full length, snugly fitting, impermeable neoprene body suit that has gaskets at the neck, wrists, and ankles to keep out water and retain the warmth of the wearer

Steerageway or Steerage Way - enough speed to create enough pressure on the rudder to make the boat respond to rudder changes, thus a change of direction of the vessel

Steering Oar or Steering Board - a long, flat board or oar that goes from the stern to well underwater, used to control the vessel in the absence of a rudder

Stem - a main frame member which is the upward extension of keel to the bow, and to which the forward ends of the planks are attached

Stem Heel - the forward Deadwood. A timber, often called the sole piece, which attaches the stem knee to the keel

Step - 1. the frame that the bottom of the mast that the mast sets into   2. to set the heel of the mast into the step

Step Jibe (Gybe) - a sailboard jibe that involves initiation by carving the turn, followed by flipping the sail and moving the feet into position on the other side of the board at the same time   See "Jibe"

Stepped - referring to where the mast step is; if the mast runs down through the vessel and the mast step is set on the keel, keel stepped; on the deck, deck stepped; on top of the cabin, cabin stepped.

Stern - the back of the boat.   See General Shipboard Directions illustration.

Stern Fast - a stern painter used to secure the stern of a boat

Stern Line - a docking line tied to the stern of the vessel

Stern Sheets - in a small, open boat, the space abaft the thwarts

Sternpost - a vertical framework extension of the keel at the aft, to which the planks are attached at the stern and to which the rudder is usually mounted

Sternway - backward motion of a vessel. Compare to Headway, Pitch,Roll, Yaw, Leeway, Drift, Surge, and Heave

Stopper Knot - a type of knot in which the end of the line, after forming a knob, passes out of the opposite end of the knot it entered. There are many stopper knots.

Stopwater - a soft wood dowel driven into the joints between backbone timbers to prevent water from leaking into the hull along the seam

Stores - supplies

Storm Jib - a small, strong, triangular headsail that is used in heavy winds

Storm Sails - a set of small, heavier weight sails for a vessel for use in high winds. See Sail on this page or Sail Plan at Wikipedia.org

Storm Surge - a rise in water level on oceans and lakes caused by high winds pushing across the water's surface and thus piling water deeper and deeper as the storm moves forward. As this water approaches and moves ashore, it may be added to a high tide if the timing is bad; causing massive destruction as it moves ashore and then retreats after the storm passes; or, if the tide is out at the time the storm comes ashore, the Storm Tide would be less destructive. This timing is very difficult for the weather service to predict.

A beautiful, full color illustration of a how storm surge works along with a high tide.

Storm Tide - Storm Surge plus the difference in Mean Tide Level and a High Tide, or Storm Surge minus the difference in Mean Tide Level and a Low Tide; which ever happens at the time a storm comes ashore.

Stove - to have planking of a hull broken in from the outside

Stow - to put or pack away

Strait - a narrow waterway joining two larger bodies of water. The Strait of Gibraltar, for example, connects the Mediterranean Sea with the Atlantic Ocean.

Strake - one row, from stem to stern, of the overlapping planks in a hull

Stretchers - athwartship, moveable planks or spars, against which oarsmen brace their feet when pulling

Stretching Screw - See Turnbuckle

Strike Sails - to shorten, douse, drop, or lower sails

Stringers - longitudinal strengthening timbers inside the hull

Strip Building - a planking method in which strips of wood are edge-fastened together to form the hull

Strongback - a heavy reinforcing timber tht runs athwartships and rests on top of the keel on some vessels like the skipjack

Studding-sails (pronounced "stuns'l") - long and narrow sails, used only in fine weather, on the outside of the large square sails of square-rigged sailing ships

Stuffing Box - a fitting that seals and lubricates the propeller shaft where it exits the hull

S-Turns - repeatedly making shallow, carved turns while still maintaining the same general course without tacking or jibing

S-Twist - twisted rope with a left-hand or clockwise lay; opposite of and less common than Z-twist rope

Suit of Sails - the full complement of the vessel's sails, all sail aloft

Superstructure - Cabins, Wheelhouse, Bridge, Deckhouses, etc., built above the decks

Surf - waves leaving deep water and breaking in shallow water

Surfing - the action of a vessel, sailing downwind, as it accelerates down the face of a wave

Surge - A vessel's transient acceleration and deceleration in a fore-and-aft direction. Compare to Pitch, Roll, Yaw, Headway, Sternway, Leeway, Drift, and Heave

Surge Brakes - Brakes on a trailer that automatically engage when momentum makes the boat press forward on the trailer hitch

Survey - an inspection done by a professional marine surveyor for the purpose of determining the seaworthyness or condition of a vessel for insurance or purchase/sale purposes

Swallow - the opening in a block, through which a line is reeved over the sheave

Swamp - to fill a vessel with water without sinking

Sway - a vessel's rotating motion from side to side; roll

Sweat and Tail - Sweatting is the act of hauling a halyard to raise a sail or spar done by pulling all slack outward and then downward. Tail is controlling, coiling, and securing the running end of the halyard. Also see Swigging

Swell - Long, drawn out waves that are created by the prevailing wind over a longer fetch than chop

Swigging - to take up the last bit of slack on a line such as a halyard, anchor line or dock line by taking a single turn round a cleat and alternately heaving on the rope above the cleat and pulling on the tail below the cleat   Also called to Veer and Haul or to Sweat and Tail.

Swim Platform - a small, horizontal deck installed behind the transom for easy boarding

Swinging the Lead - 1. measuring the depth of water beneath a ship using a lead-weighted sounding line.(Before Sonar Depth Finders)   2. a sailor who was feigning illness, etc., to avoid a hard job was said to be 'swinging the lead'.

Swing Keel - a weighted extension of a keel that can be retracted into the vessel like a centerboard or locked down in the fully extended position


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Tabernacle - a large bracket attached firmly to the deck, to which the foot of the mast is fixed. It has two sides or cheeks and a bolt forming the pivot around which the mast is raised and lowered.

Table of Offsets - in a lines plan, a table listing the key measurements from the centerline or baseline to the points where the sections cross the buttocks, waterlines, and diagonals

Tabling - the extra, strengthening, thickness of fabric sewn onto a sail's edges and corners to avoid fraying

Tachometer - an instrument that indicates the number of revolutions per minute (RPM) that your engine is running

Tack - 1. the lower corner of the sail's leading edge. On a sloop rigged sailboat, the mainsail tack is connected to the mast and the boom at the gooseneck. On the same boat, a foresail or jib tack is clipped to the forestay at the deck.  2. the corner of a spinnaker attached to the spinnaker pole.   3. The tack of a square-rigged sail is not part of the sail, but is a line attached to the lower corner (clew) of the courses.
     Most upper, square-rig sails have their clews pulled down to the yard of the sail below, and hence the position of the foot of the sail is controlled by the braces of the sail below. These sails do not have tacks. The exception to this scheme is the course (lower main sail on each square-rigged mast), which does not have a yard below it. On this sail, the sheets are led aft, and pull the clews back as well as down, taking the place of the braces of the non-existent sail below. This works perfectly well when the wind is aft of the beam, but as the ship heads further upwind the sheets become less and less effective for controlling the windward clew.
     Rather than being a simple "bag of wind", the sail must be pulled into a fairly poor, but better, approximation of an airfoil, like a modern triangular sail, by hauling the windward leech as far forward and as tight as possible. The sheet is in completely the wrong position to do this and so at this point the tack is brought into play. It is a second line attached to the clew along with the sheet, but the free or working end may be taken to a suitable point well forward of the sail and pulled taut to tighten the leech into some kind of leading edge.
     So that the tack can be repositioned easily, a tack is usually a single line rather than having blocks. A common arrangement, however, is to have a separate shorter tackle which can be hooked on to apply greater force over the last few feet of tensioning.
  4. a course sailed with the wind coming from the side of the boat or sailboard.   5. one leg of a zigzag course steered in beating to windward   6. to change course by turning into and through the eye of the wind so that the wind comes from the other side of the boat. To come about. In sailboarding, this is usually the first turn taught to beginners. It requires the sailor to move forward and around the mast to the other side of the sailboard as the board passes through the eye of the wind.

  • For Videos and Step By Step Instructions on Eleven Different Sailboard Tacks, See Royn Bartholdi's Tack Page.   His site is excellent.

Tackle - 1. the line, chain, and hooks used with a Block   2. improperly used: a Block and Tackle. See at Block on this page

Taffrail - a rail at the stern of the boat that covers the head of the counter timbers

Taffrail Log - a log consisting essentially of a rotor towed throught the water by a line attached to a distance-registering device secured at the taffrail.   Compare to Dutchman's Log and Chip Log"

Tailshaft - a metallic rod that connects the engine to the propeller on a vessel with an inboard engine. When the tailshaft is rotated by the engine, the propeller rotates for propulsion.

Tailwind - wind that you are sailing down wind with. Opposite of Headwind.

Taken Aback - an inattentive helmsmen might allow the dangerous situation to arise where the sails are back-winded, causing a sudden (and possibly dangerous) shift in the position of the sails

Take the Wind Out of His Sails - to sail directly to windward of another ship so that you block the his wind. To overbear

Tall Ship
U.S. Coastguard Cutter "Eagle"
Sailing Vessel Type: Bark
A beautiful, full color photograph of a Tall Ship.

Tall Ship - A tall ship is a large traditionally rigged sailing vessel. Traditional rigging may include square rigs and gaff rigs, with separate topmasts and topsails. It is generally more complex than modern rigging, which utilizes newer materials such as aluminum and steel to construct taller, lightweight masts with fewer, more versatile sails. It should be noted that most smaller, modern vessels use the Fore & Aft rigged Bermuda rig. Popular modern tall ship rigs include topsail schooners, brigantines, brigs and barques.

Tally - hauling aft the sheets, or pulling them toward the ship's stern

Tang - a fitting on a spar to which other rigging is attached

Tar - In nautical usage, pine tar. This tar is not the "tar" used on streets and roofs, which is really asphalt, but rather pine tar, also called Stockholm tar, an amber-colored pitch made from the sap of certain pine trees and used on ships, mixed with old rope fibers (Junk), hemp, or jute, to make oakum, to caulk joints of timbers and deck planking.

Taut-line Hitch - Landlubber's name for Midshipman's Hitch

Tell-tale - a piece of cloth or yarn that is tied or attached to a stay or sail for the purpose of acting as a wind flow indicator. When attached to shrouds, there will usually be one tell-tale on the port shroud and one on a starboard shroud. When attached to a sail, they are used as a guide when trimming (adjusting) a sail. On the mainsail, tell-tales are on the leech (aft edge) and when trimmed properly should be streaming backwards. On the jib there are tell-tales on both sides of the luff of the sail. As a general guide, the windward tell-tale should stream aft (rearward) with an occasional lift and the leeward tell-tale should stream aft.

Tender - 1. a small boat used to transport crew, passengers, and equipment from shore to a larger boat   2. a vessel is tender if she has a high center of gravity and unstable, making her heel easily. Also called Crank.

Tensile Strength - the theoretical load, in pounds of stress, at which a rope, cable, chain would break

Teredo Worm - a type of small, salt water, bivalve, marine clam that attaches itself, then bores holes and tunnels in the hulls of wooden vessels with its shells, and given time, can render a vessel disastrously unsound. In the late 18th century, it was discovered that copper repels these mollusks, so some wooden ship's hulls were covered with copper sheeting below the waterline, and eventually to paint containing copper to keep teredo worms from attaching and boring into the hulls. Copper itself is under increasing pressure to stop its use because it is harmful to other marinelife, and is already banned in some areas. The technology of the poisons used has progressed from organoarsenicals and organomercurials in the 1960s to relatively harmless organic materials today which target fouling organisms without harming other marine creatures. Teredo worms are a significant threat to wooden hulled vessels, especially in the warm waters of the Caribbean. Teredo worms are also making a comeback in US waters because of environmental improvement. In San Francisco Bay, and even the Hudson River, teredo worms are becoming an increasing threat to wooden pilings supporting harbor infrastructure.

Terylene - Another name for Dacron

Tether - a line that connects a persons safety harness to a secure part of the boat like the Jacklines

Thimble - 1. an iron loop or ring that is grooved on the outside in order to allow a line or cable to be laid in the groove thus forming a reinforced and abrasion free loop in the line or cable   2. a cup built into a sailmaker's or rigger's palm to aid in pushing needles through sail fabric or lines

Thole Pins or Tholepins - Vertical wooden pegs or pins inserted through the gunwale of a small boat to form a fulcrum for oars when rowing. Used in place of an oarlock. Simpler in manufacture, but not as effective as oarlocks because they do not hold the oar down to the gunwale.

Three Sheets to the Wind - 1. having the sheets of the three lower courses loose on a three masted ship will result in the ship meandering aimlessly downwind.   2. a sailor who has drunk strong spirits beyond his capacity

Throat - the upper foremost corner of a quadrilateral fore-and-aft rigged sail on gaff-rigged vessels; also called the "Nock"

Through-hull Fitting - any of several fixtures that allow water to pass into or out of the hull, such as for sinks, the head, engine cooling system, and the bilge. Each should have a seacock on it and the seacock should be kept closed except when in use.

Thrum Mats - small pieces of canvas with short strands of rope yarn attached to them, called Thrumming. These are placed between the oarlocks and the oars to prevent noise when pulling on the oars

Thumb Cleat - a small, one-horned cleat fixed to a mast or other spar to prevent a line such as a snotter from slipping out of place

Thwart - a lateral brace in a boat

Glossary of Tidal Terms

 
Diurnal Tides
Having only a single high and low water each day.
 
Semi-Diurnal Tides
Having two high water and two low water levels in approximately 24 hours
 
Mixed Tide
A twice daily tide of unequal high and/or low waters.
 
High Tide or High Water
The highest level reached by an ascending tide.
 
Low Tide or Low Water
The lowest level reached by a descending tide.
 
Range
The difference between high tide and the following low tide.
 
Mean Low Water (MLW)
The average height of all low water at a reference station over a 19 year cycle.
 

Mean Lower Low Water (MLLW)
The average height of the low water spring waters over a 19 year cycle.
 
Mean High Water
The average height of all high waters over a 19 year cycle.
 
Tidal Datum
A reference level from which heights and depths are measured. On a chart this is called the Chart datum. In the US, Mean Lower Low Water is used as the tidal datum. This datum is normally low enough so that the majority of low waters won't go below it.
 
Height of Tide
At any time this is the vertical measurement between the surface of the water and the tidal datum. Do not confuse height of tide with depth of water.
 
Mean Sea Level (MSL)
The average height of the surface of the ocean for all tidal stages.
 
Current
The horizontal movement of water.
 
Tidal Current
The horizontal movement of water caused by gravitational interaction between the sun, moon, and earth. Tidal currents are a part of the vertical rise and fall of the sea which we refer to as tide..
 
Non-Tidal Current
The horizontal movements of water that are not the result of tidal effects. Examples include river currents, ocean currents, and wind-driven currents. .
 
Set
The direction toward which a tidal current flows.
 
Drift
The speed of a tidal current, which is normally expressed in knots and measured to the nearest 10th of a knot. River currents are measured in mph.
 
Slack Water or Slack
The state of a tidal current when its speed is near zero, prior to reversing direction. The term is also applied to the entire period of low speed prior to and after the turning of the current when it is too weak to be of any practical importance in navigation. Not to be confused with stand. >
 
Stand
The point when vertical movement of the water ceases at both high and low tide.
 
Flood
Tidal current moving toward land or up a tidal stream.
 
Ebb
Tidal current moving away from land or down a tidal stream.
 
Charted Clearance
The difference in height between mean high water and the underside of an overhead obstruction, such as a bridge or cables.
 
Actual Clearance
The difference in height between the bottom of an obstruction and the actual surface of the water.
 
Actual Depth of Water
The charted depth plus the height of tide. When the height of tide is a negative number, the actual depth of water will be below the charted depth.
 
Charted Depth
The depth of water as shown on a chart with reference to the chart or tidal datum.

Tide - the vertical rise and fall of water caused by the effects of the moon and sun. Compare to Current   Also see related: Bore, Diurnal Inequality, Diurnal Current, Diurnal Tide, High Tide, High Water Inequality, Lower High Water, Higher High Water, Lower Low Water, Higher Low Water, Low Tide, Low Water Inequality, Mean Tide Level, Meteorological Tides, Neap Tide, Perigean Tides, Range of Tides, Ratio of Ranges, Ratio of Rise, Reference Station, Semidiurnal Tide, Slack Tide, Spring Tide, Storm Surge, Storm Tide

Tide Tables - a set of data showing the times and heights of high and low tides for one or more locations

Tie-Down - a cable or fabric strap that secures a boat to its trailer

Tie Rod - a metal bolt or threaded rod used to add structural strength, as between the cockpit carlin and the side of the hull

Tiller - a spar fitted to the rudder stock that controls the rudder and is used for steering.

Tilt Pin - a metal pin that keeps a tilt-bed trailer rigid and in place until the boat is ready for launching

Timber - all large pieces of wood used in ship-building, as floor-timbers, cross-pieces, futtocks, frames, and the like.

Timber-Heads - the heads of the timbers that rise above the decks, and are used for belaying hawsers, large ropes, &c. (See Kevel-heads.) These being such important parts of a ship, men of acknowledged talent in the royal navy are styled "the timber-heads of the profession."

Timbers - the incurvated ribs of a ship which branch outwards from the keel in a vertical direction, so as to give strength, figure, and solidity to the whole fabric. One timber is composed of several pieces.—Cant or square timbers are those which are placed obliquely on the keel towards the extremities of a ship, forming the dead solid wood of the gripe, and of the after heel.—Filling timbers are those which are put up between the frames. One mould serves for two timbers, the fore-side of the one being supposed to unite with the after-side of the one before it, and so make only one line.—Knuckle-timbers are the foremost cant-timbers on a ship's bow: the hindmost on the quarter are termed fashion-pieces.

Timoneer - from the French timonnier, a name given, on particular occasions, to the steersman of a ship

Tingle - a thin, temporary patch

Toe Rail - a low strip running around the edge of the deck like a low bulwark. It may or may not run the full length of the boat and may have gaps (scuppers) in it to allow water to flow off the deck

Toe the Line or Toe the Mark - at parade, sailors and soldiers were required to stand in line, their toes in line with a seam of the deck

Toggle - 1. a fitting which allows a turnbuckle to lie in the same straight line as the shroud or stay it is attached to.   2. a pin through an eye or bight of rope, used as a quick release

Tom - a pet bow-chaser, a 9 or 12-pounder. (canon)

Tompion - a circular plug of wood, used to stop the muzzle of a gun, and thereby keep out the wet at sea. The tompions are carefully encircled with tallow or putty for the same purpose. Also, the stopper fitted to go between the powder and shell in a mortar. This name is often pronounced as well as written tompkin

Tongue - a vertical, pivoting wooden block inserted in the jaws of the gaff to keep the gaff from binding an it slides up and down on the mast

Top - a platform at the upper end of each (lower) mast of a traditional square rigged ship. The Top act as anchors for the shrouds of the topmast that extends above it. Above the mainmast (for example) is the main-topmast, main-topgallant-mast and main-royal-mast, so that the top is actually about 1/4 to 1/3 of the way up the mast as a whole. This is not the Crow's Nest.

Topgallant - the mast or sails above the topsails

Topmast - the second section of the mast above the deck; formerly the upper mast, later surmounted by the topgallant mast; carrying the topsails

Topping lift - 1. a line that holds up the boom when it is not being used.   2. a line from the masthead that controls the height of a spinnaker pole

Topsail - the second sail (counting from the bottom) up a mast. These may be either square sails or fore-and-aft, in which case they often "fill in" between the mast and the gaff of the sail below.

Topsail Schooner - See at Types of Sailboats on this page

Topsides - 1. the part of the hull between the waterline and the deck. Also called Above-water hull   2. on deck, as opposed to below decks

Touch and Go - having the bottom of the keel touch the bottom, but not grounding

Track - 1. the actual, wandering path sailed by a vessel from point of departure to point of arrival.   Compare to Course, Course Made Good, and Heading   2. a metal or plastic fitting used to control or guide sails, blocks, or the ends of some spars

Prevailing Winds of the World
An illustration showing the Prevailing Winds of the World, the Arctic and Antartic Circles, the Tropics of Cancer and Capricorn, the Equator, the Northern and Southern Horse Latitudes, the Westerlies or Anti-Trades, the Northeast and Southeast Trade Winds, the Doldrums, the Roaring Forties, Furious Fifties, and the Screaming Sixties
Click Image to Enlarge
Copyright 2012 Rick McClain

Tradewinds - persistent tropical winds that blow westward and toward the Equator. They are stronger and more consistent over the oceans than over land and often produce partly cloudy sky conditions, characterized by shallow cumulus clouds, or clear skies. Their average speed is about 8 to 11 knots (11 to 13 miles per hour) but can increase to speeds of 26 knots (30 miles per hour) or more. The trade winds blow predominantly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere, strengthening during the winter and at times when the air pressure is high over the poles.
   The term trade winds originally derives from the early fourteenth century late Middle English word 'trade' meaning "path" or "track", but was soon put into use by the sailors of trading ships to indicate the winds that bore their ships westward for trade. The Portuguese recognized the importance of the trade winds in navigation in the Atlantic ocean as early as the 15th century. The full wind circulation includes both the Tradewind easterlies just north and south of the doldrums of the equator and higher-latitude Westerlies.

Traffic Separation Scheme - Shipping corridors marked by buoys which separate incoming from outgoing vessels. Often, improperly called Sea Lanes.

Trail Boards - a pair of ornamental boards mounted on either side from the bowsprit to the bow; sometimes flanking a figurehead

Trailing Lines - small lines secured to the gunwale and around the oars to prevent the oars from getting adrift when trailed from swivel oarlocks

Trampoline - a tightly stretched mesh between the pontoons of a catamaran or trimaran that acts as a deck for the sailors to move around on

Transderm Scop - a prescription (Scopolamine) adhesive patch worn on the skin behind the ear to prevent sea sickness by depressing the action of the nerve fibers near the ear and the vomiting center of the brain and central nervous system. Follow the directions carefully, as the medication may make the pupils of your eyes dilate causing poor near vision and high susceptability to sun damage. Wear dark eye protection.

Transition Board - a sailboard between 10 and 11 feet in length (305-335cm) that has a daggerboard

Transom - a more or less flat surface across the outer part of the stern of a vessel. Dinghies tend to have almost vertical transoms, whereas yachts' transoms may be raked forward or aft. It usually bears the name of the vessel.

Trap - a form over which steamed hull frames may be bent before being installed into the hull

Trapeze - a line and harness, suspended from the mast of a sailing vessel that allows the crew to hike all their weight out over the windward edge of the boat in order to move the center of gravity further away from the mast and avoid capsizing in higher winds. Compare to Hiking Board

Traveler - 1. a bar or track secured athwartships on the deck or cabin top so that the sheet of a sail, mounted to the boom with a block and slide, can move back and forth smoothly,   2. thin iron rings encircling the backstays, which are used for hoisting the topgallant yards

Traveling Block - the freely moving block of a block and tackle that contains a set of pulleys or sheaves through which the line is threaded or reeved. The Traveling Brock moves with the weight while the Standing Block, which is attached to the support, remains stationary.   See Block

Treenail (pronounced TRUN-ul) - a wooden dowel driven through a snug hole in adjoining timbers in order to join them together. A small wedge is then driven into each end of the treenail to expand the ends and hold them in place.

Trestletree - a pair of timbers or metal bars running parallel to the centerline of the vessel, supported by the Bibbs and lying along the tops of the Hounds or Cheeks of a lower mast section to support Crosstrees or a Top

Trice or Trice Up - to haul upward and tie up with a short rope

Tricing Line - a line that draws up a sail from the bottom; used to reduce sail by raising its foot.

Trick - a period of time spent at the helm (wheel or tiller)("my trick's over")

Trim - 1. to adjust the sails   2. the position of the sails   3. to adjust the weight of the cargo, ballast, and crew of a ship to ride evenly through the water   4. the fore-and-aft balance of the position in which a vessel sits in the water

Trimaran - a sailing vessel with three hulls; usually two pontoons of equal size on either side of a larger, central hull.

Trip Line - a line connected to the crown of the anchor used to free the anchor if it becomes fouled or buried too deeply   2. a line with which a sea anchor may be emptied and hauled aboard

Trisail - See Trysail

Tropic of Cancer - the parallel of latitude approximately 23° 27' north. It circles the Earth about one-quarter of the way from the equator to the North Pole and marks the farthest point north that the sun can appear to be directly overhead at any given point when the sun is at its northern most point. This is when the sun is at its greatest distance from the celestial equator, which happens at the June solstice (longest day of the year in the northern hemisphere, shortest day of the year in the southern hemisphere) on about 21 June. It forms the boundary between the Torrid (Tropic) and Northern Temperate zones.   See illustration at Prevailing Winds of the World

Tropic of Capricorn - the parallel of latitude approximately 23° 27' south. It circles the Earth about one-quarter of the way from the equator to the South Pole and marks the farthest point south that the sun can appear to be directly overhead at any given point when the sun is at its southern most point. This is when the sun is at its greatest distance from the celestial equator, which happens at the December solstice (shortest day of the year in the northern hemisphere, longest day of the year in the southern hemisphere) on about 22 December. It forms the boundary between the Torrid (Tropic) and Southern Temperate zones.   See illustration at Prevailing Winds of the World

Trough - the depression between two waves

Truck - the cap at the summit of a masthead or flagstaff

True Bearing - a bearing relative to True North. See also: Absolute Bearing, Magnetic Bearing, Relative Bearing, and Bearing

True North - the direction to the North Pole as measured by the axis of the rotation of the earth, rather than the magnetic north pole of the earth's magnetic field. The two points are not geographically the same and thus cause variations in compass readings that need compensation as a vessel moves about the seas. Compare to Magnetic North

True Wind - the wind as measured by a stationary device

Trunk - the enclosure for the centerboard

Trunnel - See Treenail

Trunnion - either of the two cylindrical projections on a cannon, one on each side for supporting the cannon on its carriage

Trysail - a small fore-and-aft sail used in very high winds or in storms to maintain control, to avoid ship damage, and to keep the bow to the wind. It is hoisted abaft or on the mainmast (taking the place of the much larger mainsail) and is usually used best without the boom to avoid having the boom swinging in very strong winds and high seas.

Tumblehome - tumblehome is the narrowing of a ship's hull from the waterline to the weather deck. Expressed more technically, it is present when the beam at the uppermost deck is less than the maximum beam of the vessel. A small amount of tumblehome is normal in many designs in order to allow any small projections at deck level to clear wharves. Tumblehome was common on wooden warships for centuries. In the era of oared combat ships it was quite common, placing the oar ports as far abeam as possible and making it more difficult to board by force, as the ships would come to contact at their widest points, with the decks some distance apart. The narrowing of the deck above this point made the boat more stable by lowering the weight above the waterline, which is one of the reasons it remained common during the age of cannon-armed ships.

Tuning - the adjustment of the standing rigging, the sails and the hull to balance the boat for optimum performance. On a sailboard, the adjustment of the downhaul, outhaul, and batten tensions to make a specific sail perform best.

Tunnel Hull - a hull with tunnels shaped for the propeller in order to reduce the draft of the vessel

Turn - a curve in a line (rope) such that the ends cross. Compare to Bight and Loop

Turnbuckle - a link with opposing, lefthand and righthand threaded eye-screws that shorten or lengthen their span as the link is rotated in order to tighten or loosen rods, or lines, like shrouds, that it connects. The turnbuckle allows them to be tightened after they are rigged.   Also called Bottlescrew or Stretching Screw.

Turning Blocks - horizontally mounted blocks used to redirect lines on the deck.   See Block

Turning Circle - 1. the course made when a vessel is turning   2. the tightest course possible when the helm is hard over

Turn-of-the-Bilge - in a round-bottomed boat, the curve, just at or below waterline, where the bottom meets the topsides

Turtle - to turn a sailboat totally upside down so the mast is straight down in the water and the hull of the vessel is exposed to the air, like a turtle's shell

Twilight - a period of incomplete darkness before sunrise or after sunset

  • Civil Twilight - a period of incomplete darkness before sunrise or after sunset, lasting from when the sun's center is between 0° and 6° below the horizon. This corresponds to a degree of illumination at which everyday operations begin or cease to be possible without artificial light. Few, if any, stars are visible.
  • Nautical Twilight - that period before sunrise and after sunset when the center of the sun is 6° below the horizon, but not more than 12° below. During this interval of incomplete darkness, the degree of illumination is such that general outlines are still discernible, although detailed operations become impossible. All the bright stars are visible at this time. It is the time when the navigational stars are visible and the sea horizon is still sufficiently visible to permit celestial observations with a sextant.
  • Astronomical Twilight - the time of night when the center of the Sun is between 12° and 18° below the horizon. All but the dimmest stars and nebulae will be visible. From the end of astronomical twilight in the evening to the beginning of astronomical twilight in the morning, the sky (away from urban light pollution) is dark enough for all nightime astronomical observations.

Twing - a short line at each side of a boat to control the spinnaker sheets

Twist or Twist Off - the amount that the leech near the top of the sail falls off to leeward

Two Blocked - Chock-a-Block; when the tackle is pulled so far that the two blocks of a block and tackle are pulled tight against each other and cannot move closer

Two Half Hitches - a simple, but dependable hitch with many uses. The Two Half Hitches knot is one of the eight most useful knots everyone should know.

Types of Sailboats - See the sail configurations of many types of sailboats and ships including a Sloop, Cutter, Yawl, Ketch, Schooner, Brig, Barquentine, Barque, Bragana or Felluca, Polacre, Junk and Full Rigged Ship.   Link opens a new window.   Compare to: Rig

  • Catboat - a boat with a single mast and a single sail
  • Sprit - a single masted vessel with a spritsail, which uses a "sprit" or spar leading from the lower part of the mast to, and supporting, the peak of the mainsail, and a jib. The shape of the sail can be adjusted by changing the tension on the sprit with the snotter.
  • Knockabout - a single masted, fore-and-aft rigged vessel with no bowsprit; the foresail being set from a stay at the stem
  • Sloop - a single masted, fore-and-aft rigged vessel (gaff rigged, or triangular sails) with a foresail to the bowsprit; thus allowing a larger jib than a knockabout
  • Cutter - 1. a single masted, fore-and-aft rigged vessel that has the mast stepped further aft than the conventional sloop, about two-fifths of the way aft measured on the water line, allowing for a larger jib or dual jibs. 2. a ship's boat having double-banked oars and one or two lugsails. 3. Also, a revenue cutter; a lightly armed government vessel used to prevent smuggling and enforce the customs regulations. 4. A U.S. Coast Guard Cutter - the Coast Guard calls any CG vessel 65 feet in length or greater, having adequate accommodations for crew to live on board, "Cutters".
  • Ketch - a dual masted, fore-and-aft rigged vessel whose aftermost mast is much shorter and is forward of the rudderpost
  • Yawl - a dual masted, fore-and-aft rigged vessel whose aftermost mast is much shorter and is abaft the rudderpost

    Said by a helmsman, "I can reach forward and 'Ketch' my mizzen boom; 'Yawl' can't." A play on words that will help remember which vessel is a ketch and which is a yawl; since the mizzen mast and boom are behind the helmsman on a yawl.

  • Lugger - a small sailing vessel setting lugsails on two or more masts and perhaps lug topsails
  • Schooner - a multi-masted (two to seven masts), fore-and-aft, and usually gaff rigged, vessel whose foremost mast is not taller than the main mast, but may be equal in height
Full Rigged Ship
Norwegian Ship "Christian Radich"
A Full Rigged Ship, showing its Square Rigged Sails.
  • Galley - a vessel whose main propulsion was rowing, but had some square sails. It was in use from 3000 years ago until the 1700's. Some had as many as three levels of rowers and in excess of 300 rowers, almost always, slaves.
  • Galleon - a large, multi-decked, square rigged vessel of the 16th to 18th centuries with 3 to 5 masts with a lateen sail on the mizzenmast. The principal warships of the opposing English and Spanish fleets in the 1588 confrontation of the Spanish Armada were galleons and were the prototype for all three or more masted, square rigged ships for over two and a half centuries, including the coming full rigged ship.
  • Brig - two masted, square rigged; fore and mainmast
  • Brigantine - two masted, mainsail (only) is fore-and-aft rigged
  • Hermaphrodite Brig - two masted, square rigged foremast, all sails on mainmast are fore-and-aft rigged
  • Bark - three masts or more, all square rigged except fore-and-aft rig of aftermast
  • Barkentine - three masts or more, all fore-and-aft rigged except square rigged foremast
  • Topsail Schooner - has fore-and-aft rigging except for square rigged foretopsail
  • Ship or Full Rigged Ship - Three or more masts, all square rigged
  • Frigate - a long, low, fast, well armed Man of War in the form of a Ship.   See Ship above.

THESE LINKS ALL OPEN IN NEW WINDOWS
Types of Sailing Vessels
Barca-longa       Barque       Barquentine       Bermuda Sloop       Bilander       Brig       Brigantine       Caravel       Carrack       Catamaran       Catboat       Clipper       Dutch_clipper       Cog       Corvette       Cutter       Dhow       Dinghy       East_Indiaman       Felucca       Fifie       Fluyt       Frigate       Full_rigged_ship       Fusta       Galeas       Galiot       Galleon       Hermaphrodite Brig       Herring Buss       Hoy       Jackass-Barque       Junk       Ketch       Longship       Lugger       Man-of-War       Mersey Flat       Nao       Nordland       Norfolk Punt       Norfolk Wherry       Pink       Pinnace       Pocket Cruiser       Polacca or Polacre       Pram       Proa       Punt       Razee       Sailboard       Sailing Hydrofoil       Schooner       Ship of the Line       Sixareen       Sgoth       Sloop       Sloop of War       Smack       Snow       Tall Ship       Thames Sailing Barge       Trailer Sailer       Trimaran       Vinta       Wherry       Windjammer       Windsurfer       Xebec       Yacht       Yawl       Yoal      

Typhoon - the name given strong tropical cyclonic winds in the western Pacific and Indian Ocean; called "Hurricanes" most other places. In the Indian Ocean and South China Sea, the Beaufort Scale is extended by the addition of Numbers 13 through 17 because of the frequency of extremely forceful Typhoons in those areas.


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U     (TOP OF PAGE)     (Sailboard Diagram)     (Sailboat Diagram)     (Warship Diagram)

U-Joint - a universal joint

Under Sail - with sails set; in motion; sailing

Under Way - moving through the water with a watercraft, whether powered or not

Underwater Hull - the portion of a vessel beneath the waterline, normally not visible except when in drydock.

Uphaul - 1. (Uphaul Rope or Line) a rope attached to the front of the boom on a sailboard to enable the sailor to raise the sail from the water. 2. to extricate the sail of a sailboard rig from the water by over-straining your back as you tug on the uphaul line, all the while precariously balancing on top of an unstable sailboard as it heaves, pitches, rolls, yaws, and surges on the waves

United States Coast Guard (USCG) - the federal marine law enforcement and rescue agency in the U.S.

United States Power Squadrons (USPS) - a private membership organization that teaches good boating practices and safety

United States Yacht Racing Union (U.S.Y.R.U.) - the controlling organization of all yacht racing in the U.S.A.

Universal or Universal Joint - a rubber or mechanical connection on the mast base of a sailboard that lets the mast rotate or pivot at its base in any direction, thus letting it fall over into the water. A sailboard is steered by leaning the mast forward to turn to leeward and leaned back to turn to windward

Universal Time, Coordinated (UTC) - Coordinated Universal Time (UTC) is used as the official world reference for time. Coordinated Universal Time replaced the use of Greenwich Mean Time (GMT) in 1972. UTC, also called Zulu Time, is an indication of the offset between a local time and Greenwich Mean Time (GMT).
You will often see time zones represented like "UTC-5h" or "GMT-5h"or "Z-5h". In this example the "-5h" refers to that time zone being five hours behind UTC or GMT and so forth for the other time zones. "UTC+5h" or "GMT+5h" would refer to that time zone being five hours ahead of UTC of GMT and so forth for the other time zones.
The usage of UTC and GMT is based upon a twenty four hour clock, similar to military time, and is based upon the 0° longitude meridian, referred to as the Greenwich meridian at the British Royal Observatory in Greenwich, England. Coordinated Universal Time is based on cesium-beam atomic clocks, with leap seconds added to match earth-motion time, whereas Greenwich Mean Time is based upon the Earth's rotation and celestial measurements.
The local mean solar time at the Royal Observatory, Greenwich, England, United Kingdom, was chosen at the 1884 International Meridian Conference to define the Universal day, counted from zero hours at mean midnight.

So, for example, according to the chart below, if is 0900 hours (9:00 AM) in Greenwich, England, you would need to subtract 7 hours from that time to determine the time where I live in Salt Lake City, Utah (UTC-7h or Z-7h or Mountain Standard Time); thus it would be 0200 hours or 2:00 AM.   If it were 0330 hours (3:30 AM) in Greenwich, it would be 2230 hours (10:30 PM) of the previous evening in New York City, New York (UTC-5h or Z-5h or Eastern Standard Time).

Time Zone in United States

Examples of places in United States  using these Time Zones

UTC Offset
Standard Time

UTC offset
Daylight Saving Time

Atlantic

Puerto Rico, US Virgin Islands

UTC - 4h

n/a

Eastern

Connecticut, Delaware, Florida, Georgia, part of Indiana, part of Kentucky, Maine, Maryland, Massachusetts, Michigan, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, part of Tennessee, Vermont, Virginia and West Virginia

UTC - 5h

UTC - 4h

Central

Alabama, Arkansas, Florida, Illinois, part of Indiana, Iowa, part of Kansas, part of Kentucky, Louisiana, part of Michigan, Minnesota, Mississippi, Missouri, Nebraska, North Dakota,  Oklahoma, part of South Dakota, part of Tennessee, most of Texas, and Wisconsin

UTC - 6h

UTC - 5h

Mountain

Arizona*, Colorado, part of Idaho, part of Kansas, Montana, part of Nebraska, New Mexico, part of North Dakota, part of Oregon, part of South Dakota, part of Texas, Utah, and Wyoming

UTC - 7h


UTC - 6h
* n/a for Arizona

Pacific

California, part of Idaho, Nevada, most of Oregon, Washington

UTC - 8h

UTC - 7h

Alaskan

Alaska

UTC - 9

UTC - 8

Hawaiian

Hawaii

UTC - 10

n/a


Unlay - to open up or separate the strands of a line

Unreeve - to remove a line from a hole, grommet, cringle, block, etc.

Upper Shrouds - the mast support wires that run from the chainplates at the sides of the boat over the spreaders and to the masthead

Upwind - Windward. The area and sailing courses that are toward the source of the wind


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V     (TOP OF PAGE)     (Sailboard Diagram)     (Sailboat Diagram)     (Warship Diagram)

Vaka - the main hull of a trimaran, Proa, or similar sailing vessels

Vane - a small flag flown at each mast head to show wind direction

Vang - a rope leading from gaff to either side of the deck, used to prevent the gaff from sagging

Vanishing Angle - the maximum degree of heel after which a vessel becomes unable to return to an upright position.

Variation - an effect on compass readings caused by the fact that True North and Magnetic North are not located in the same spot on the earth's surface, causing differences in readings of True North and Magnetic North as a vessel moves about the seas. The lines of force between the north and south magnetic poles do not run in parallel lines, so the difference between the magnetic and true north varies all over the globe. Variation is shown on good charts and since there is no way to correct the compass for variation, the course must be adjusted to take it into account. You must subtract Westerly variation from the Compass Reading to find the true course and add Easterly variation. Thus, if the variation at a particular place in the world is 10° West, the True course will be less than the Compass course, i.e. if your Compass reads 275°, your True course is 265°. If the variation were10° East, the Compass course to steer would be 270° to be on a True course of 260°.   Compare to Deviation

V-Berth - the two forward berths, configured in a "V" pattern to fit into the bow of a small vessel

V-Bottomed Hull - a displacement hull whose underwater hull has a deep "V" shape as the sides meet at the bottom

V-Drive - a mechanism that allows a boats engine to be mounted 180° from normal. It is a transmission mounted forward of the engine which reverses the direction of the shaft so that it can exit aft. This arrangement is used in some small powerboats so that the engine may be mounted all the way aft to free up cockpit space.

Vector - a line drawn to represent both magnitude and direction; such as leeway a vessel makes in a given time period as a result of wind or water currents

Veer - 1. to turn a vessel away from the wind; Wear   2. to have the wind shift in a clockwise direction. Opposite of Back   3. to slacken or pay out a line, chain or cable   4. to lead a line around a bitt or block, thereby changing its direction for a purchase.

Veer and Haul - 1. to alternately pull sideways on the bight (middle) of a line and then pull on its snubbed end so as to further tighten the line.  Also called Swigging or to Sweat and Tail.

Vent - an opening for a vessel's ventilation system

Ventilator or Vent - an opening, fitted with cowls (scoops) to direct the flow of fresh air and vapors in or out of ducts

Very Light - a flare or fireball shot into the air as a warning or signal of distress

Very Pistol - handgun used to launch flares into the sky as a warning or signal of distress, named for Edward Very (1847-1910) an American Naval officer who designed a breech loading, short barrel pistol to launch marine flares. A flare gun.

Vessel - a craft for traveling on, through, or under the water. Ships, powerboats, sailboats, rowboats, barges, submarines, houseboats, sailboads, and canoes are vessels; docks and buoys are not.

VHF - Very High Frequency. Radio frequencies between 30 and 300 megahertz, used for marine radio transmission and reception. Marine VHF radio is installed on all large ships and most seagoing small craft. It is used for a wide variety of purposes, including summoning rescue services and communicating with harbours, locks, bridges and marinas.

VMG or Velocity Made Good - the calculation of the speed on the ideal route towards the goal. For instance, if you have to sail a heading that is 45° to starbord or port of your goal, and sail at 10 knots on that heading, you will have only 7 knots Velocity Made Good

Volume (of a sailboard) - the amount of water displaced, usually given in liters, by a sailboard that is submerged. The higher the volume, the heavier the sailor and larger the sail, the board will support.

Voyage - a round trip involving an outward passage and homeward passage.   Compare to Passage


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W     (TOP OF PAGE)     (Sailboard Diagram)     (Sailboat Diagram)     (Warship Diagram)

Waist - the central part of a vessel's deck between the forecastle and the quarterdeck

Wake - the "v-shaped" swell or waves caused by a boat passing through water

Wakeless Speed - the low speed at which a vessel is propelled through water without creating waves that might cause nuisance, disruption, or damage to others   Compare to Dead Slow and Bare Steerage Speed

Wales - a number of strong and thick planks running length-wise along the ship, covering the lower part of the ship's side

Wardroom - originally known as the Wardrobe Room, a place where officers kept their spare wearing apparel. It was also the space where any loot, secured from enemy ships, was stored. In an effort to have some privacy on a crowded ship, officers would sometimes take their meals in the Wardrobe Room. Today, the Wardroom aboard ship is where officers take their meals, relax and socialize.

Warp - 1. to pull the stern of a vessel to one side using a small anchor (a kedge) in order to change the ship's heading, as when having to turn in a small radius while at anchor.   2. to turn a docked vessel by applying force to the lines tied to the dock.   Compare to Kedge

Wash - the turbulence behind a vessel or from its propeller.

Ship's Watches
Watch Name Bells Rung 12 Hour Clock 24 Hour Clock
Middle Watch 8 Bells
thru
8 Bells
Midnight
thru
4:00 AM
2400 Hours
thru
0400 Hours
Morning Watch 8 Bells
thru
8 Bells
4:00 AM
thru
8:00 AM
0400 Hours
thru
0800 Hours
Forenoon Watch 8 Bells
thru
8 Bells
8:00 AM
thru
Noon
0800 Hours
thru
1200 Hours
Afternoon Watch 8 Bells
thru
8 Bells
Noon
thru
4:00 PM
1200 Hours
thru
1600 Hours
First Dog Watch 8 Bells
thru
4 Bells
4:00 PM
thru
6:00 PM
1600 Hours
thru
1800 Hours
Last Dog Watch 4 Bells
thru
8 Bells
6:00 PM
thru
8:00 PM
1800 Hours
thru
2000 Hours
First Watch 8 Bells
thru
8 Bells
8:00 PM
thru
Midnight
2000 Hours
thru
2400 Hours

Watch - 1. the duty crews of a vessel, usually divided into two; starboard watch and larboard (port) watch. A man may sleep or relax when not on watch.  . 2. a period of time during which a part of the crew or watch is on duty; usually for four hours at a time, except near dinner time, when watches are usually two hours long (Dog Watches). Most of the crew of a ship are divided up into between two and four duty groups called watches, depending on the size of the crew. Each watch takes its turn with the essential activities of manning the helm, navigating, trimming sails, and keeping a lookout. Changes of watch are marked by strokes on the ship's bell; usually starting at eight bells - Midnight (2400 hours), 4:00 A.M. (0400 hours), 8:00 A.M. (0800 hours), Noon (1200 hours), 4:00 P.M. (1600 hours)(First Dog Watch), 6:00 P.M. (1800 hours) (Last Dog Watch), , and 8:00 P.M. (2000 hours).   The purpose of the Dog Watch is to shift the watches each night, so that the same watch shall not be on deck at the same hours throughout a voyage. In order to affect this, the watch from four to eight P.M. (the Dog Watch) is divided into two half-watches, one from four to six p.m., and the other from six to eight p.m. By this means they divide the twenty-four hours into seven watches instead of six, and thus shift the hours every night. The choice of time also allows both watches, if there are only two, to eat an evening meal at about the traditional time, usually at two bells (5:00 P.M.) (1700 hours) during the First Dog Watch, and at the change of the watch at four bells (6:00 P.M.) (1800 hours) (beginning of Last Dog Watch).

Watch and Watch - the regular alternation in being on watch and off watch of the two watches into which a ship's crew is commonly divided. If a ship has enough crew to divide them into three or more duty groups or watches, then they are not "Watch and Watch".

Water Ballast Tank - water held in tanks onboard a vessel as ballast. This makes taking on or getting rid of ballast quick and easy. Some high tech vessels can move significant amounts of water into the windward tank or tanks quickly in order to keep the vessel on an even keel.

Waterline - 1. an imaginary and moving (But sometimes painted on (Actually, the painted stripe is the "Boot Top" or "Boot Stripe")) line circumscribing the hull that matches the surface of the water. As the vessel heels, pitches, rolls, lists, or takes on cargo, the waterline changes.   2. in a lines plan. the contour lines that represent horizontal, lengthwise slices of the hull's surface, parallel with its load waterline.   The portion of the hull above the waterline of a well trimmed boat sitting at rest in calm water is the "topsides" and the portion below is the "bottom."

Waterspout - a small-diameter column of rapidly swirling and upward-moving air in contact with a water surface that sucks water into the air. Waterspouts are almost always produced by a swiftly growing cumulus cloud. They may assume many shapes and often occur in a series, called a waterspout family, produced by the same upward-moving air current. Waterspouts are closely related to other atmospheric phenomena such as tornadoes, whirlwinds, and fire storms.

Waterway - a heavy plank or timber, about twice the thickness of the deck planking, extending fore-and-aft the whole length of a vessel's deck, laid against the frames or bulwark stanchions, forming a channel to the scuppers, which are cut through it for the purpose of draining water off the deck

Water Start - In sailboarding, a technique for getting underway while the sailor is down in the water and by filling the sail with wind overhead, the sail lifts the sailor onto the board and into a sailing posture. Learning this technique totally changes your enjoyment of the sport for the better.

Wave - undulations of the sea. The height of a wave is measured vertically from trough to crest; the length is the distance between crests; the period is the time between two successive crests. There are numerous conditions that cause waves; wind, underwater disturbances of the bottom, earthquakes on land, land or ice falling into the water, etc. There are three basic types of wave: 1. Non-breaking   2. Spilling Breakers, whose crest topples gently over and pours down the face of the wave without breaking free of the wave's surface   3. Plunging Breakers, whose crest arcs and falls free, forward, onto the wave. Non-breaking waves may become spilling or plunging breakers as they approach shallower water; an opposing current (tidal, river, etc.) flows against the wind; or if the wind pumps more energy into the wave system in a short time

Wave Board - Small, light, more maneuverable sailboards for use in breaking waves and surf. Characteristically, sailors on wave boards perform high jumps while sailing against waves, and they ride the face of a wave performing narrow linked turns (bottom turns, cutbacks, and top-turns) in a similar way to surfing. Wave boards usually have a volume between 65 and 90 liters, with a length between 230 and 260 centimeters, and 50 to 60 centimeters in width. A general rule is for a sailor to use a wave board whose volume in liters is about the same as the sailor's weight in kilograms - more volume providing additional flotation for sailing in light winds, and less for high winds, where less volume is needed to achieve planing. In recent years, the average width of wave boards has increased slightly, as the length has shrunk, while the range of volume has been maintained the same more or less - according to board designers this makes wave boards easier to use under a wider range of conditions by sailors of different abilities. The most common sizes of sails used with wave boards are in the range of 4.0 to 6.0 square meters, depending on the wind speed and the weight of the sailor.

Wave Fin - a sailboard skeg that angles toward the stern and is shaped like an inverted dorsal fin of a dolphin

Wave Sail - an RAF sailboard sail that is designed with a high foot so that the foot won't get caught on waves while sailing in the surf

Way - movement of a vessel through the water such as headway, sternway or leeway

Wearing or Wearing About or Wearing Ship - a jibe (gybe) through more than 180 degrees, performed by square-rigged vessels in order to avoid the dangers that square-rigged vessels face when tacking. Opposite of a "Chicken Jibe"   See "Jibe"

Weather - 1. to pass to windward of another vessel or object.   2. to successfully ride out a squall or storm

Weather Deck - the deck that is exposed to the weather; usually either the main deck or, in larger vessels, the upper deck

Weather Gage - favorable position over another sailing vessel with respect to the wind

Weather Helm - a tendency of a vessel with poorly trimmed sails to continually try to turn upwind. On a sailboard, this can be corrected by moving the mast base sternward in the mast track. Weather helm indicates that the forces acting on the sail are out of balance with the center of lateral resistance. Most of the time, weather helm is considered a problem and the aim is to reduce the amount of effort required to steer the vessel. A little weather helm is good in limited amounts since it gives the helm a positive feel when steering and allows the helmsman to monitor how the boat reacts to changing wind conditions. However, any time you're struggling to fight the helm and the rudder is cranked over to one side just to keep the boat going straight, not only are you tiring yourself out unnecessarily, but you are also slowing the vessel down. Some helmsmen like the feel of a little weather helm because it can also indicate when to follow advantageous windshifts, called lifts, when heading upwind. To control excessive weather helm, first make sure that your sails are trimmed well inboard. Then start easing the mainsail's traveler to leeward (if you have an adjustable traveler), or tighten the vang and ease the mainsheet.   Opposite of Lee Helm.   Also see Balanced Helm

Weather Shore - the coast lying in the direction from which the wind is blowing; as opposed to the Lee Shore

Weather Side - the side exposed to the wind. Windward side.

Weatherly - a ship that is easily sailed and maneuvered; makes little leeway when sailing to windward

Weed Fin - a skeg for a sailboard that is angled sharply toward the stern and has a straight leading edge in order to avoid snagging seaweed

Weigh Anchor - to heave up (raise) (an anchor) preparatory to sailing

Well - a place in the ship's hold for the bilge pump

Westerlies - The Westerlies, anti-trades, or Prevailing Westerlies, are the prevailing winds in the middle latitudes between 30 and 60 degrees latitude, blowing from the high pressure area in the horse latitudes towards the poles. These prevailing winds blow from the west to the east. The winds are predominantly from the southwest in the Northern Hemisphere and from the northwest in the Southern Hemisphere.
     The Westerlies are strongest in the winter and times when the pressure is lower over the poles, while they are weakest in the summer and when pressures are higher over the poles. The Westerlies are particularly strong, especially in the southern hemisphere, where there is less land in the middle latitudes to cause the flow pattern to amplify, or become more north-south oriented, which slows the Westerlies down. The strongest westerly winds in the middle latitudes can come in the Roaring Forties, between 40 and 50 degrees south latitude. The Westerlies play an important role in carrying the warm, equatorial waters and winds to the western coasts of continents, especially in the southern hemisphere because of its vast oceanic expanse. The full wind circulation includes both the Westerlies and the Tradewinds.   See illustration at Prevailing Winds of the World

Wetsuit - a snugly fitting permeable neoprene body suit that retains the warmth of the wearer

Wetted Surface - the total area of the wet portion of a vessel; hull and rudder.

Wharf - a structure built on the shore of or projecting into a harbor, lake, river, etc., so that vessels may be moored alongside to load or unload or to lie at rest; quay; pier, dock.

Wheel - a circular, usually spoked, handwheel for controlling the tiller and rudder on a vessel. Many small vessels have no wheel, only a tiller

Whip - binding the strands at the end of a line or on an eye splice with small marline or cord to add strength and keep it from fraying. See Knot on this page

Whipping - a binding knot tied with small line on the end of a larger line, used to prevent the end of the larger line from fraying. Serving. See at Knot on this page

Whisker Pole - a light spar which holds the jib out away from the mast when sailing downwind. Similar, but lighter in weight and strength than a spinnaker pole

Whistle Signal - a standard communication signal between vessels by means of horn, whistle or similar devise, to indicate change in course, danger, or other right of way situations. The whistle signals required by Rules of the Road are described in blasts; a short blast is a blast of about 1 second in duration, a prolonged blast, 4 to 6 seconds, and a long blast should be 8 to 10 seconds.

Whitecap - a small, wind-generated, breaking wave with white froth at the breaking point of the wave

White Horses - waves in wind strong enough to produce foam or spray off the wave tops.

Widow Maker - a term for the bowsprit (many sailors lost their lives falling off the bowsprit while tending sails)

Wig Wag - an obsolete, but simple, method of transmitting Morse code using one flag attached to a staff. The flag is held vertically and waved to the right to signal a dot and to the left to signal a dash. The space between words is indicated by lowering the flag in front of the signalman.   Compare to Semaphore Flags

Wildcat - a sprocketed wheel in a modern windlass with indentations for the links of the anchor chain. The wildcat, when engaged, either hauls in or pays out the anchor chain. When disengaged, the wildcat turns freely and the only control of the anchor chain is the friction brake.

Winch - a metal drum shaped device used to assist in trimming sails and other situations where an increase in mechanical advantage is needed in hoisting or hauling. A line is wrapped around the drum once or more, depending on how much friction is required, and a crank is used to turn it, or it may be run by electrical power.

  • Drum Winch - a winch on which a line is wrapped two or three times and the free end (tail) is usually dropped onto the deck or into the cockpit
    • Self-Tailing Winch - winches that have a "stripper" or cleat to maintain tension.
    • Snubbing Winch - This is a vertical spool with a ratchet mechanism similar to a conventional winch, but with no crank handle or other form of drive. The line is wrapped around the spool and can be tightened and reeled in by pulling the tail line, the winch takes the load once the pull is stopped with little operator tension needed to hold it. They also allow controlled release of the tension by the operator using the friction of the line around the ratcheted spool. They are used on small sailing boats and dinghies to control sheets and other lines.
  • Reel Winch - a winch that stores the line by winding it up in layers; like in on a fishing reel. Usually used for steel halyards, etc.
See Sailboat Winches at Mauri Pro Sailing for more information.

Windage - wind resistance of the boat

Windbound - a condition wherein the ship is detained in one particular station by contrary winds

Wind Chill Factor - the dangerous cooling effect of wind due to evaporation and removal of heat from an object that can cause hypothermia even in moderate temperatures

Windfall - 1. a rush of wind from the high land.   2. a stroke of good luck

Windhole - an area without wind

Windlass - a winch mechanism, usually with a horizontal axis. Used where mechanical advantage greater than that obtainable by block and tackle was needed (such as raising the anchor on ships). In the "Age of Ships" the windlass set below the Capstan, which drove the windlass, on another deck. Now, most windlasses are powered by electricity, hydraulically, pneumatically or via an internal combustion engine. For more information see Anchor Windlass" at Wikipedia.

Windline - a line on the surface of the water caused by wind of a higher velocity (gusts) hitting the water's surface, causing larger ripples to form, and marked by a darker surface appearance. Watch for these windlines upwind of your position. They indicate the nearly precise position of stronger wind that will affect you momentarily.

Windmill - in rowing, to raise the oars too high out of the water and then bury them too deep on the power stroke

Wind of Motion - the wind created by the movement of a vessel through the air

Wind-Over-Tide - sea conditions with a tidal current and a wind in opposing directions, leading to short, heavy seas

Wind Scoop - a funnel used to force wind into a hatch and ventilate the area below decks

Wind Shadow - turbulence to leeward of a sail, point of land, or other structure

Wind's Eye - the direction from which the true wind comes

Wind Ship Pronounced with a long "I" as in "Find" - to turn a vessel end for end; at a dock, for instance

Windsurfer - the trademarked name of the sailboard patented by Hoyle Schweitzer and Jim Drake in 1968 and manufactured by Windsurfing International in Torrence, California. They defended their patent rather unsuccessfully and the patent expired in 1987.

Wind Shift - a change in direction of the true wind

Wind Snob - someone who refuses to sail unless the wind is sufficiently high for his or her, obviously superior, skills

Windvane - a non-electrical, relatively inexpensive, reliable, mechanical self-steering device for a boat, usable in virtually all conditions except "no wind".
In a mechanical windvane self-steering gear the sensor is not a compass but a wind sensitive vane. This vane sensor or air vane is set for a desired point of sail. The sensor is connected to a steering device of some kind. When the angle of the wind relative to the course of the boat (the apparent wind) changes, this change is registered by the air vane, which activates the steering device to return the boat to the selected point of sail.
Windvane self-steering does not steer a constant compass course but a constant point of sail. When using the vane gear in practical life you first sail the boat on the desired compass heading. Then you trim and balance the boat for this course. After the boat is balanced the vane sensor is set and the vane gear is engaged to steer the boat at the point of sail which corresponds to your desired compass course.
If the wind changes direction, the vane gear, steering at a preset angle to the wind, will cause the yacht to change course away from the desired compass heading. This property seems to create a feeling that vane gears cannot be "trusted" like autopilots. That, however, is a faulty assumption. On a sailboat it is actually preferable to use a self-steering device that steers by the apparent wind, keeping the boat from gybing or backing its sails, which an autopilot could do in a wind change. If it is extremely important to steer a straight compass course while sailing, both an autopilot and a vane gear have to be supervised. A change in wind direction will require retrimming in both cases to stay on the desired heading.
Out at sea the wind does not change often or drastically in direction. Moderate deviations can be tolerated. The vane gear will steer more efficiently as it steers by the wind, keeping the boat at optimum trim when you go upwind and minimizing the chance of an accidental gybe when you go downwind.   Compare to Auto Pilot

Windward - upwind

Windward Helm - Same as Weather Helm - the tendancy of a sailboat to turn upwind when the helm is released. On a sailboard, this can be corrected by moving the mast base sternward in the mast track.

Wing and Wing or Wing on Wing - positioning of the mainsail and jib on opposite sides of the centerline as when running.

Wishbone Boom - an elliptical boom that splits at the mast and goes around each side of the sail, reconnecting at its tail at the clew of the sail; as on a sailboard

Workboat - a vessel used for chores like ferrying stores, or putting down or moving moorings

Working Sails - the everyday set of sails used under normal sailing conditions; as opposed to "Racing or Light Wind Sails" or "Storm Sails"   See Sail on this page or Sail Plan at Wikipedia.org

Worms - See Teredo Worm

Worm, Serve, and Parcel - to protect a section of rope from chafing by: laying yarns (worming) to fill in the cuntlines, wrapping marline, small chord or other small line around it (serving, also called whipping), and stitching a covering of canvas (parceling) over all


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Y     (TOP OF PAGE)     (Sailboard Diagram)     (Sailboat Diagram)     (Warship Diagram)

Yacht - a recreational boat. It designates two rather different classes of watercraft, sailing and power yachts. Yachts are differentiated from working ships mainly by their leisure purpose, and are basically fancy houseboats. However, since the level of luxury on larger yachts has seen an increasing trend, the use of the word yacht to mean any sailing vessel has been diminishing and is more and more limited to racing yachts or cruising yachts. Yacht lengths generally start at 32-35 feet (10-11 m) and go up to hundreds of feet. A mega yacht generally refers to any yacht (sail or power) above 100 ft (34 m) and a super yacht generally refers to any yacht over 200 ft (70 m). This size is small in relation to typical cruise liners and oil tankers.

Yankee - a fore-sail flying above and forward of the jib, usually seen on bowsprit vessels

Yar or Yare (pronounced "yahr" - (Said of a ship) quick to the helm; easily handled or maneuvered

Yard - 1. the horizontal spar from which a square sail is suspended. Not to be mistaken for yardarm.   2. the spar from which a quadrilateral fore-and-aft sail like a spanker or lugsail is suspended.   3. an area where boats are built, stored or repaired   Compare to Gaff and Sprit

Yardarm - the very end of a yard. Often mistaken for a "yard", which refers to the entire spar; as in to hang "from the yardarm"

Yare or Yar (pronounced "yahr" - (Said of a ship) quick to the helm; easily handled or maneuvered

Yaw - A vessel's motion rotating about the vertical axis, so the bow rotates from side to side. This is caused by over-steering or by heavy seas.   Compare to Pitch, Roll, Headway, Sternway, Leeway, Drift, Surge, and Heave

Yawl - a dual masted, fore-and-aft rigged vessel whose aftermost mast is much shorter and is abaft the cockpit.   Compare to other sailboat types

Yoke - the crosspiece fitted on the rudderhead of a small boat and used for steering where a tiller would be impractical. A pair of lines leading from the ends of the yoke control the rudder.


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Z     (TOP OF PAGE)     (Sailboard Diagram)     (Sailboat Diagram)     (Warship Diagram)

Zephyr - a gentle breeze. The west wind.

Z-Twist - twisted rope with a right-hand or counter clockwise lay, the most common twist in twisted rope; opposite of S-twist

Zodiak - a brand of very popular inflatable and rigid inflatable boats (RIBs) used by SCUBA divers because of their stability and ease of boarding from the water and as tenders by much of the boating community

Zulu Time - the difference between local time and Greenwich Meridian Time or Greenwich Mean Time (GMT). Zulu time is sometimes denoted by the letter "Z", a reference to the equivalent nautical time zone (GMT), which has been denoted by a Z since about 1950. Since the NATO phonetic alphabet and amateur radio word for Z is "Zulu", UTC is sometimes known as Zulu time. This is especially true in aviation, where Zulu is the universal standard. This ensures everyone, regardless of location is using the same 24-hour clock, thus avoiding confusion when navigating between time zones.   See Universal Time


(TOP OF PAGE)     (Sailboard Diagram)     (Sailboat Diagram)     (Warship Diagram)


For further information see the following:

Sailboats at Wikipedia.org

Types of Ships at Wikipedia.org

Sail Plans for Ships at Wikipedia.org

Parts of a Sail at Wikipedia.org

Rick McClain wishes to thank the many resources used to compile this page; especially:
Wikipedia, Burr Hazen's Windsurfing Bible, Royn Bartholdi's Great Sailboarding Web Site


The Bluejackets' Manual - United States Navy
The Ashley Book of Knots by Clifford W. Ashley
Piloting, Seamanship and Small Boat Handling by Charles F. Chapman
American Practical Navigation by Nathaniel Bowditch


For a copius explanation of mariner's terms from the 1700's, see:

William Falconer's Dictionary of the Marine
Published 1769 & 1780

...and a Personal Thank You to:
Jeff Longmore at Thin Film Technology for his contribution of knowledge on Anti-Fouling and Teredo Worms.

I certainly hope that if you detect errors, non-working links, see a need for additions, have comments or criticism about my page, or just felt like this was a worthwhile resource; you'll please contact me at the email address below.


Want to see what Rick really does? See his images at:
Rick McClain Photography


Copyright 2008 - 2013     Rick McClain Photography
Salt Lake City, Utah
U.S.A.
(801) 484-8488

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