Nautical Terms

Below is a glossary of some useful nautical terms.

ABOARD - On or within the boat.

ADRIFT - Loose, not on moorings or towline.

AFT - Towards the stern (back) of the boat.

AFTERNOON WATCH - The 1200-1600 watch.

AGROUND – Resting on or touching the ground or bottom (usually involuntarily).

AHEAD - In a forward direction.

ASTERN - In back of the boat, opposite of ahead.

BATTEN DOWN - Secure hatches and loose objects both within the hull and on deck.

BAIN - also bo's'n or bos'n or bo·sun (bsn) - A warrant officer or petty officer in charge of a ship's rigging, anchors, cables, and deck crew

BEAR DOWN or bear away – Turn away from the wind, often with reference to a transit.

BEATING – Sailing as close as possible towards the wind (perhaps only about 60°) in a zig-zag course to attain an upwind direction to which it is impossible to sail directly.(also tacking)

BEAUFORT SCALE – The scale describing wind force devised by Admiral Sir Francis Beaufort in 1808, in which winds are graded by the effect of their force (originally, the amount of sail that a fully-rigged frigate could carry). Scale now reads up to Force 17

BOW - The front of a boat.

BOWLINE - A knot used to form a temporary loop in the end of a line.

BURGEE – A small flag, typically triangular, flown from the masthead of a yacht to indicate yacht-club membership.

BRIDGE - The location from which a vessel is steered and its speed controlled.

BRIDLE - A line or wire secured at both ends in order to distribute a strain between two points.

BULKHEAD - A vertical partition separating compartments.

BUOY - An anchored float used for marking a position on the water or a hazard and for mooring.

CABIN - A compartment for passengers or crew.

CAPSIZE - To turn over.

CAST OFF - To let go.

CATAMARAN - A twin-hulled boat, with hulls side by side.

CENTERBOARD - a retractable fin keel used on sailboats to prevent drifting to leeward, usualy rotates on a pin

CHART - A map for use by navigators.

CLEAT - A stationary device used to secure a rope aboard a vessel.

COURSE - The direction in which a boat is steered.

CURRENT - The horizontal movement of water.

DAGGERBOARD - A type of light centerboard that is lifted vertically

DEAD AHEAD - Directly ahead.

DEAD ASTERN - Directly aft (behind).

DINGHY - A small open boat.

DISPLACEMENT - A boat is said to be a displacement boat when it is essentially moving through the water rather than over the water.

DOG WATCH - a work shift, between 1600 and 2000 (4pm and 8pm). This period is split into two, with the first dog watch from 1600 to 1800 (4pm to 6pm) and the second dog watch from 1800 to 2000 (6pm to 8pm). Each of these watches are half the length of a standard watch.

EBB - A receding current or tide

FENDER - A cushion, placed between boats, or between a boat and a pier, to prevent damage.

FIRST WATCH - The 2000-0000 watch.

FLARE - A distress signal.

FLOOD - A incoming curren

FORENOON WATCH - The 0800 to 1200 watch

FORWARD - Toward the bow of the boat.

GENOA - A larger front sail than a jib, often has a window in it.

GLOBAL POSITIONING SYSTEM – (GPS) A satellite based radionavigation system providing continuous worldwide coverage. It provides navigation, position, and timing information to air, marine, and land users.

GOING ABOUT or tacking – Changing from one tack to another by going through the wind (see also gybe).

GOOSENECK – Fitting that attaches the boom to the mast, allowing it to move freely.

GOOSEWINGED - Of a fore-and-aft rigged vessel sailing directly away from the wind, with the sails set on opposite sides of the vessel – for example with the mainsail to port and the jib to starboard, to maximize the amount of canvas exposed to the wind. Also see running.

GUNWALE - Upper edge of a boat's sides.

GYBE - or jibe (both pronounced /ˈdʒaɪb/) – To change from one tack to the other away from the wind, with the stern of the vessel turning through the wind. (See also going about and wearing ship.)

HALYARD or halliard – Originally, ropes used for hoisting a spar with a sail attached; today, a line used to raise the head of any sail.

HATCH - An opening in a boat's deck fitted with a watertight cover.

HEAD - A toilet on a vessel.

HEADING - The direction in which a vessel's bow points at any given time.

HITCH - A knot used to secure a rope to another object or to another rope, or to form a loop or a noose in a rope.

HULL - The main body of a vessel.

JIB - A triangular sail at the front of a ship.

JURY RIG – Both the act of rigging a temporary mast and sails and the name of the resulting rig. A jury rig would be built at sea when the original rig was damaged, then it would be used to sail to a harbor or other safe place for permanent repairs.

KEEL - The centerline of a boat running fore and aft (front to rear).

KNOT - A measure of speed equal to one nautical mile (1,852m) per hour. Originally speed was measured by paying out a line from the stern of a moving boat. The line had a knot every 47 feet 3 inches (14.40 m), and the number of knots passed out in 30 seconds gave the speed through the water in nautical miles per hour.

LATITUDE - The distance north or south of the equator measured and expressed in degrees.

LEEWARD - On or toward the side to which the wind is blowing. The lee side or quarter.

LINE - Rope used aboard a vessel.

LONGITUDE - The distance in degrees east or west of the meridian at Greenwich, England.LUFF UP – To steer a sailing vessel more towards the direction of the wind until the pressure is eased on the [sheet].

MARLINSPIKE - A tool for opening the strands of a rope while splicing.

MIDDLE WATCH - The 0000 to 0400 watch

MORNING WATCH - The 0400 to 0800 watch

NAUTICAL MILE - One minute of latitude; approximately 1,852m - about 1/8 longer than the statute mile of 1,600m.

OVERBOARD - Over the side or out of the boat.

PINTLE -The pin or bolt on which a ships rudder pivots. The pintle rests in the gudgeon.PIPE (Bos'n's), or a bos'n's call – A whistle used by Boatswains (bosuns or bos'ns) to issue commands. Consisting of a metal tube which directs the breath over an aperture on the top of a hollow ball to produce high pitched notes. The pitch of the notes can be changed by partly covering the aperture with the finger of the hand in which the pipe is held.

PLANING - A boat is said to be planing when it is essentially moving over the top of the water rather than through the water.

PORT - The left-hand-side of a boat when looking forward. Denoted with a red light at night.

QUARTERDECK - The aftermost deck of a warship. In the age of sail, the quarterdeck was the preserve of the ship's officers.

READY ABOUT – A call to indicate imminent tacking, usually followed by the command "lee ho"(see going about).

RUDDER - A vertical plate or board for steering a boat.

SPINNAKER – A large sail flown in front of the vessel while heading downwind.

SPINNAKER POLE – A spar used to help control a spinnaker or other sail

SQUALL - A sudden, violent wind often accompanied by rain.

STARBOARD - The right-hand-side of a boat when looking forward. Denoted with a green light at night.

STERN - The rear part of the boat.

TIDE - The periodic rise and fall of water level of a body of water due to the gravitational pull of the moon.

TILLER - A bar or handle for turning a boat's rudder or an outboard motor.

TRANSOM - The stern cross-section of a square sterned boat.

TRIM - Fore and aft balance of a boat.

UNDERWAY - When a vessel is in motion i.e. not moored.

WAKE - Moving waves, track or path that a boat leaves behind it, when moving across water.

WATCHES - The traditional Royal Navy watch system, those members of the crew whose work must be done at all times of the day are assigned to one of two divisions: the Starboard or the Port division. These two groups of personnel alternate in working the following watches:

  • First watch - 2000 to 0000
  • Middle watch - 0000 to 0400
  • Morning watch - 0400 to 0800
  • Forenoon watch - 0800 to 1200
  • Afternoon watch - 1200 to 1600
  • First dog watch - 1600 to 1800
  • Last dog watch - 1800 to 2000

WEIGH ANCHOR – To heave up (an anchor) preparatory to sailing.

WINDWARD - Toward the direction from which the wind is coming.