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  • aft (adj.) – towards the back or stern of a boat
  • aloft (adj.) – high above the deck of a ship in the rigging or on a mast
  • autopilot (n.) – an instrument designed to steer a boat and automatically maintain a predetermined course


  • barograph (n.) – a barometer that records its readings on a moving chart
  • barometer (n.) – an instrument for measuring atmospheric pressure and forecasting the weather
  • beam (n.) – the width of a ship at the widest part
  • bearing (n.) – a determination of position; one point’s position with respect to another or to the compass
  • beat (v.) – to sail a boat to windward (into the wind) by tacking
  • berth (n.) – 1: a space for anchoring or tying up; 2: a job or position; 3: a built-in bed or bunk
  • bilge (n.) – the bottommost interior part of a ship; the inner, lower part of a ship’s hull
  • block (n.) – a wooden, metal or plastic case containing pulleys, through which turns of line are threaded for the purpose of gaining mechanical advantage or changing the direction of motion
  • boom (n.) – a spar extending from a ship’s mast to hold the bottom of a sail outstretched
  • broach (v.) – “when boat rounds up into the wind and lays over on its side, sails in water, luffing; maybe 50 degrees heeling; results in a big mess onboard when boat is overpowered like this” – definition by Rich Wilson
  • bulkhead (n.) – any of the upright partitions separating parts of a ship to protect against leakage


  • capsize (v.) – to overturn
  • car (n.) – a sliding fitting that attaches to a track, allowing for the adjustment of blocks or other devices attached to the car; also known as a slide
  • catamaran (n.) – a boat with two connected but distinct parallel hulls
  • chart (n.) – a map used in marine navigation
  • clew (n.) – the lower aft corner of a mainsail or jib, or either lower corner of a square sail
  • clipper (n.) – a sharp¬bowed, narrow¬beamed sailing ship built for great speed
  • cockpit (n.) – a sunken space in the deck of a boat, usually towards the stern and for use by the helmsman
  • “come about” (v.) – to change course so that the sail(s) shift from one side of the boat to the other; to tack
  • companionway (n.) – a hallway or ladder passage aboard a ship
  • compass (n.) – an instrument that shows direction, especially with the aid of a magnetic needle which swings freely and points to magnetic north
  • coordinate (n.) – any of a set of numbers in a reference system (e.g., on a map) that determine the location of a point (or ship)
  • course (n.) – the direction in which a ship is moving, based on the 360¬degree compass; bearing
  • cuddy (n.) – a small compartment on a boat
  • current (n.) – the horizontal motion of water, caused by tides, local winds and trade winds


  • daggerboard (n.) – a dagger-shaped board that projects down into the water below a sailboat’s hull; its purpose is to help keep the boat on course
  • deck (n.) – a part of a ship that serves both as a floor and as a full or partial covering for lower ship levels
  • desalinator (n.) – a machine that removes salt from sea water to make fresh water
  • doldrums (n.) – a part of the ocean near the equator abounding in calms, squalls, and light shifting winds


  • ensign (n.) – a flag or banner displayed on a ship
  • equator (n.) – an imaginary circle around the earth, equidistant from the North and South Poles, which divides the earth into the Northern and Southern Hemispheres


  • fathom (n.) – a nautical measure of depth or distance equal to 6 feet
  • fixed rigging (n.) – also called standing rigging, fixed rigging is the cables used to support the mast on a sailboat; these cables can be loosened and tightened to optimize the boat’s sailing ability (also see running rigging)
  • fore (adj.) – towards the front or bow of a boat
  • furl (v.) – to fold or roll up tightly and secure a sail


  • gale (n.) – a nautical term defining weather conditions in which wind speed ranges between 34 to 40 knots
  • galley (n.) – the kitchen of a ship
  • Great Circle (route) (n.) – represented by a line drawn between two points on a sphere | click for audio definition by Rich


  • halyard (n.) – a rope used for raising and lowering a flag or sail
  • hatch (n.) – a covered opening in a ship’s deck through which entrance can be made to a lower deck
  • head (n.) – the bathroom (or sink, shower and toilet) aboard a boat
  • heading (n.) – the direction in which a moving ship is pointed, usually expressed in compass degrees
  • headsail (n.) – any sail set forward of the foremast
  • headwind (n.) – a wind blowing towards the bow of the boat
  • “heave to” (v.) – to stop the forward movement of a sailboat by bringing the vessel’s bow into the wind; when a vessel is heaved to, the crew can go about other business aboard the vessel without having to tend to the helm
  • heel (v.) – to lean or tilt to one side, as a ship or boat in a high wind
  • helm (n.) – the steering apparatus of a ship, such as a wheel or tiller
  • hull (n.) – the body of a boat


  • immersion suit (n.) – a special bodysuit designed to protect a person from the cold and wet in emergencies
  • “in irons” (adj.) – headed into the wind
  • INMARSAT (n.)INternational MARitime SATellite; a satellite communication system used by ships at sea to communicate with other ships or with land-based locations


  • jib (n.) – a triangular sail secured to a stay forward of the mast
  • jibe (v.) – to pass the stern of a boat through the wind during a tack


  • keel (n.) – a ship’s principal structural member, running lengthwise along the hull, to which the frames are attached
  • knot (n.) – rate of motion equal to 1 nautical mile or 6,076 feet per hour (about 1.15 miles per hour)


  • lap (n.) – a single turn of a lashing (Use in a sentence: Thirty laps of cord were wrapped around the two ropes to hold them together securely.)
  • lash (v.) – to fasten something with rope or cord by tighly wrapping or binding it
  • lashing (n.) – an arrangement of rope or line used to secure two or more items together in a somewhat rigid manner (Source:
  • latitude (n.) – one of two coordinates (the other being longitude) used to locate a position at sea; marked in de grees north or south of the equator, from 0 degrees at the equator to 90 degrees north or south at the poles; one degree of latitude = 60 nautical miles; latitude is comparable to the x-axis on a graph
  • lazarette (n.) – a small storage area on a boat, usually located aft and below deck
  • leech (n.) – the aft or trailing edge of a sail; the aft edge of a fore-and-aft sail
  • leeward (adj.) – in the direction towards which the wind is blowing
  • lift (n.) – a change in the wind direction that allows a skipper to point his sailboat more directly at his destination
  • line (n.) – a rope used on a ship
  • log (n.) – a daily record of a ship’s speed, progress, etc. and the events in its voyage; logbook
  • longitude (n.) – one of two coordinates (the other being latitude) used to locate a position at sea; marked in degrees east or west of the Prime Meridian (0 degrees longitude) located in Greenwich, England; longitude may range up to 180 degrees east or west; 180 degrees east and west, in fact, meet on the other side of the globe from Greenwich, at the International Date Line; longitude is comparable to the y-axis on a graph


  • mainsail (n.) – the largest sail on the ship
  • “make fast” (v.) – to firmly fasten or secure
  • mast (n.) – a tall vertical spar that rises from the keel or deck of a vessel to support the sails and rigging
  • meridian (n.) – a line of longitude
  • monohull (n.) – a boat with one hull


  • nautical mile (n.) – a nautical unit of measurement equaling 1.15 statute (land) miles



  • pawl (n.) – each of a set of short stout bars that engage with the teeth of a cogwheel or ratchet and prevent a capstan, windlass, or winch from recoiling.
  • port (n.) – the left side of a boat when facing forward



  • radar (n.) – a system or device which uses transmitted and reflected radio waves to detect objects, along with their direction, distance, height, and speed in relation to the device
  • reach (v.) – to sail with the point-of-sail between close-hauled and a run, with the wind coming from across the side of the boat
  • reef (n.) – the part of a sail which is rolled up to reduce the area exposed to the wind during a storm
  • reef (v.) – to shorten or reduce the size of a sail, usually done because of heavy winds
  • Rhumb line (n.) – a line on a sphere that crosses all meridians (lines of longitude) at the same angle; another way to define it is the line drawn between two points on a Mercator projection map | click for audio definition by Rich
  • rigging (n.) – the ropes and chains used to support, position and control a vessel’s masts, sails, yards, etc.
  • rudder (n.) – a broad, flat, movable piece of wood or metal, hinged vertically to the ship’s stern; used for steering
  • run (v.) – to sail with the wind astern
  • runner (n.) – a mobile shroud located at the rear of the mast*
  • running rigging (n.) – the series of cables, ropes and/or chains on a boat that control the sails (also see fixed rigging)


  • set (v.) – to raise (e.g., a sail) into position
  • shackle (n.) – a U-shape fitting closed with a pin across the open ends and used to secure sails to lines or fittings, lines to fittings, fittings to fittings, anchors to chain, etc.
  • sheave (n.) – (Pronounced shiv): a pulley used on a boat, sometimes alone and sometimes in tandem with other pulleys
  • sheet (n.) – a rope used to control a sail’s angle to the wind
  • shoal (n.) – a sandbar or shallow area in the ocean
  • shroud (n.) – part of the standing rigging that helps to support the mast by running from the top of the mast to the side of the boat; sailboats usually have one or more shrouds on each side of the mast
  • spar (n.) – a stout rounded wood or metal piece (mast, boom, gaff, or yard) used to support rigging
  • spinnaker (n.) – a large, triangular headsail (at the front of a boat), used when reaching or running
  • spreader (n.) – a strut leading off a vessel’s mast to hold the rigging wires out and keep the mast straight; a horizontal support used to spread shrouds on a mast.
  • squall (n.) – a brief, violent storm
  • standing rigging (n.) – also called fixed rigging, standing rigging is the cables used to support the mast on a sailboat; these cables can be loosened and tightened to optimize the boat’s sailing ability (also see running rigging)
  • starboard (n.) – the right side of a ship when facing forward
  • stay (n.) – a heavy rope or cable, usually made of wire, used as a brace or support for a ship’s mast
  • staysail (n.) – a triangular fore-and-aft rigged sail fastened on a stay
  • stern (n.) – the back end of a boat
  • strike (v.) – to lower or take down (e.g., a sail)


  • tack (v.) – to bring the wind to the other side of a ship by bringing the bow through the wind
  • tiller (n.) – a lever in a boat that is attached to the rudder and used to steer the boat; a tiller is present on some boats instead of a steering wheel
  • trade wind (n.) – a wind that blows steadily towards the equator from the northeast in the tropics north of the equator and from the southeast in the tropics south of the equator
  • trim (v.) – to adjust (e.g., sails)
  • trimaran (n.) – a boat with three connected but distinct parallel hulls
  • turnbuckle (n.) – a piece of hardware on a boat that, by turning it around threaded rods, can tighten or loosen fixed rigging or cables in small increments photo


  • watch (n.) – any of the periods of duty into which the day is divided on a ship, so that the work is shared among alternating shifts of the crew
  • waypoint (n.) – coordinates (latitude and longitude) that define a location along a route of travel; can also be a physical location (an island, buoy, lighthouse, etc.) along a sailing route
  • winch (n.) – a hauling or lifting device consisting of a rope, cable, or chain winding around a horizontal rotating drum, turned by a crank or by motor
  • windward (adj.) – in the direction from which the wind is coming


* Source: