Glossary of Sailing Terms

A

Abaft – Toward the stern, relative to some object (“abaft the fore hatch”)
Abaft the beam – A relative bearing of greater than 90 degrees from the bow. e.g. “two points abaft the port beam.”
Abeam – ‘On the beam’, a relative bearing at right angles to the centreline of the ship’s keel.
Aboard – On or in a vessel. Close aboard means near a ship.
Admiralty law – Body of law that deals with maritime cases. In UK administered by the Probate, Divorce and Admiralty Division of the High Court of Justice.
Aft – Towards the stern (of the vessel)
Aground – Resting on or touching the ground or bottom.
Ahead – Forward of the bow.
Alongside – By the side of a ship or pier.
Amidships (or midships) – In the middle portion of ship, along the line of the keel.
Anchor – An object designed to prevent or slow the drift of a ship, attached to the ship by a line or chain; typically a metal, hook like, object designed to grip the bottom under the body of water.
Anchorage – A suitable place for a ship to anchor. Area of a port or harbor.
Anchor ball – Black shape hoisted in forepart of a ship to show that ship is anchored in a fairway.
Anchor chain or cable – Chain connecting the ship to the anchor.
Anchor light – White light displayed by a ship at anchor. Two such lights are displayed by a ship over 150 feet (46 m) in length.
Astern – Toward the stern; an object or vessel that is abaft another vessel or object.
Athwart, athwartships – At right angles to the fore and aft or centreline of a ship
Awash – So low in the water that the water is constantly washing across the surface.

B

Backstays – Long lines or cables, reaching from the rear of the vessel to the mast heads, used to support the mast.
Bar – Large mass of sand or earth, formed by the surge of the sea. They are mostly found at the entrances of great rivers or havens, and often render navigation extremely dangerous, but confer tranquillity once inside. See also: Touch and go, grounding. Alfred Lord Tennyson’s poem ‘Crossing the bar’ an allegory for death.
Beacon – A lighted or unlighted fixed aid to navigation attached directly to the earth’s surface. (Lights and day beacons both constitute beacons.)
Beam – The beam of a ship is its width at the widest point, or a point alongside the ship at the mid-point of its length.
Bear away – Turn away from the wind, often with reference to a transit.
Bearing – The horizontal direction of a line of sight between two objects on the surface of the earth.
Berth – A bed on a boat, or a space in a port or harbour where a vessel can be tied up.
Bilge – The bilge is the compartment at the bottom of the hull of a ship or boat where water collects so that it may be pumped out of the vessel at a later time.
Bimini – Weather-resistant fabric stretched over a stainless steel frame, fastened above the cockpit of a sailboat or flybridge of a power yacht which serves as a rain or sun shade.
Binnacle – The stand on which the ship’s compass is mounted.
Boat – A craft or vessel designed to float on, and provide transport over, water.
Boom – A spar used to extend the foot of a for-and-aft sail.
Boom vang (vang) – A sail control that lets one apply downward tension on the boom, countering the upward tension provided by the mainsail. The boom vang adds an element of control to mainsail shape when the mainsheet is let out enough that it no longer pulls the boom down. Boom vang tension helps control leech twist, a primary component of sail power.
Buoy – A floating object of defined shape and colour, which is anchored at a given position and serves as an aid to navigation.
Bow – The front of a ship.
Bowline – A type of knot, producing a strong loop of a fixed size, topologically similar to a sheet bend. Also a rope attached to the side of a sail to pull it towards the bow (for keeping the windward edge of the sail steady).
Bowsprit – A spar projecting from the bow used as an anchor for the forestay and other rigging.
Broaching-to – A sudden movement in navigation, when the ship, while scudding before the wind, accidentally turns her leeward side to windward, also use to describe the point when water starts to come over the gunwale due to this turn.
Bulkhead – An upright wall within the hull of a ship. Particularly a load bearing wall.
By and Large – By means into the wind, while large means with the wind. By and large is used to indicate all possible situations “the ship handles well both by and large”.
By the board – Anything that has gone overboard.

C

Cable – A large rope; also 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.
Capsize – When a ship or boat lists too far and rolls over, exposing the keel. On large vessels, this often results in the sinking of the ship.
Capstan – A huge rotating hub (wheel) mounted vertically and provided with horizontal holes to take up the capstan bars (when manually rotated), used to wind in anchors or other heavy objects; and sometimes to administer flogging over.
Careening – Cause the ship to tilt on its side, usually to clean or repair the hull below the water line.
Catamaran – A vessel with two hulls.
Centreboard – A removable keel used to resist leeway.
Chafing – Wear on line or sail caused by constant rubbing against another surface.
Chine – A relatively sharp angle in the hull, as compared to the rounded bottoms of most traditional boat hulls.
Civil Red Ensign – The British Naval Ensign or Flag of the British Merchant Navy, a red flag with the Union Flag in the upper left corner.
Cleat – A stationary device used to secure a rope aboard a vessel.
Club hauling  – The ship drops one of its anchors at high speed to turn abruptly. This was sometimes used as a means to get a good firing angle on a pursuing vessel.
Coaming – The raised edge of a hatchway used to help keep out water.
Companionway – A raised and windowed hatchway in the ship’s deck, with a ladder leading below and the hooded entrance-hatch to the main cabins.
Compass – Navigational instrument that revolutionised travel.
Cunningham – A line invented by Briggs Cunningham, used to control the shape of a sail.

D

Daggerboard – A type of centreboard that is removed vertically.
Deadrise – The design angle between the keel (q.v.) and horizontal.
Decks – the structures forming the approximately horizontal surfaces in the ship’s general structure. Unlike flats, they are a structural part of the ship.
Deck hand – A person whose job involves aiding the deck supervisor in (un)mooring, anchoring, maintenance, and general evolutions on deck.
Deckhead – The under-side of the deck above. Sometimes panelled over to hide the pipe work. This panelling, like that lining the bottom and sides of the holds, is the ceiling.
Directional light – A light illuminating a sector or very narrow angle and intended to mark a direction to be followed.
Dog watch – A short watch period, generally half the usual time (e.g. a two hour watch between two four hour ones). Such a watch might be included in order to slowly rotate the system over several days for fairness, or to allow both watches to eat their meals at approximately normal times.
Dolphin – A structure consisting of a number of piles driven into the seabed or riverbed in a circular pattern and drawn together with wire rope.
Downhaul – A line used to control either a mobile spar, or the shape of a sail.
Draught –The depth of a ship’s keel below the waterline.

F

Fathom – A unit of length equal to 6 feet (1.8 m), roughly measured as the distance between a man’s outstretched hands.
Fender – An air or foam filled bumper used in boating to keep boats from banging into docks or each other.
First Mate – The Second in command of a ship
Flag hoist – A number of signal flags strung together to convey a message, e.g. ‘England expects…’.
Fluke – The wedge-shaped part of an anchor’s arms that digs into the bottom.
Following sea – Wave or tidal movement going in the same direction as a ship
Foot – The bottom of a sail.
Forecastle – A partial deck, above the upper deck and at the head of the vessel; traditionally the sailors’ living quarters. Pronounced ‘focsle’. The name is derived from the castle fitted to bear archers in time of war.
Fore – Towards the bow (of the vessel).
Forefoot – The lower part of the stem of a ship.
Forestays – Long lines or cables, reaching from the front of the vessel to the mast heads, used to support the mast.
Freeboard – The height of a ship’s hull (excluding superstructure) above the waterline. The vertical distance from the current waterline to the lowest point on the highest continuous watertight deck. This usually varies from one part to another.
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.
Furl– To roll or wrap a sail around the mast or spar to which it is attached.

G

Gaff – The spar that holds the upper edge of a fore-and-aft or gaff sail. Also a long hook with a sharp point to haul fish in.
Galley – the kitchen of the ship
Garboard – The strake closest to the keel (from Dutch gaarboard).
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.
Gunwale – Upper edge of the hull.

H

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.
Handsomely – With a slow even motion, as when hauling on a line “handsomely.”
Hank – A fastener attached to the luff of the headsail that attaches the headsail to the forestay. Typical designs include a bronze or plastic hook with a spring-operated gate, or a strip of cloth webbing with a snap fastener.
Harbor – A harbor or harbour, or haven, is a place where ships may shelter from the weather or are stored. Harbours can be man-made or natural.
Hawse-hole – A hole in a ship’s bow for a cable or chain, such as for an anchor, to pass through.
Head – The toilet or latrine of a vessel, which for sailing ships projected from the bows
Headsail – Any sail flown in front of the most forward mast.
Heaving to – To stop a sailing vessel by lashing the helm in opposition to the sails. The vessel will gradually drift to leeward, the speed of the drift depending on the vessel’s design.
Heeling – Heeling is the lean caused by the wind’s force on the sails of a sailing vessel.
Helmsman – A person who steers a ship
Hogging or hog – The distortion of the hull where the ends of the keel are lower than the centre.
Horn – A sound signal which uses electricity or compressed air to vibrate a disc diaphragm.
Hull – The shell and framework of the basic flotation-oriented part of a ship
Hydrofoil – A boat with wing-like foils mounted on struts below the hull.

I

In Irons – When the bow of a sailboat is headed into the wind and the boat has stalled and is unable to manoeuvre
Inboard-Outboard drive system – A larger Power Boating alternative drive system to transom mounted outboard motors.

J

Jack – Either a flag, or a sailor. Typically the flag was talked about as if it were a member of the crew. Strictly speaking, a flag is only a “jack” if it is worn at the jackstaff at the bow of a ship.
Jacklines or Jack Stays – 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 on the safety harness to secure the crew to the vessel while giving them the freedom to walk on the deck.
Jib – A triangular staysail at the front of a ship.

K

Keel – The central structural basis of the hull
Kelson – The timber immediately above the keel of a wooden ship.
Know the ropes – A sailor who ‘knows the ropes’ is familiar with the miles of cordage and ropes involved in running a ship.

L

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. Believed to be from the Anglo-Saxon word hiaeder, meaning ladder.
Lanyard – A rope that ties something off.
Larboard – The left side of the ship (archaic, see port). cf. starboard. Derived from the old ‘lay-board’ providing access between a ship and a quay.
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).
League – A unit of length, normally equal to three nautical miles.
Leech – The aft or trailing edge of a fore-and-aft sail; the leeward edge of a spinnaker; a vertical edge of a square sail. The leech is susceptible to twist, which is controlled by the boom vang and mainsheet.
Lee side – The side of a ship sheltered from the wind (cf. weather side).
Lee shore – A shore downwind of a ship. A ship which cannot sail well to windward risks being blown onto a lee shore and grounded.
Leeway – The amount that a ship is blown leeward by the wind. See also weatherly.
Leeward – In the direction that the wind is blowing towards.
Line – the correct nautical term for the majority of the cordage or “ropes” used on a vessel. A line will always have a more specific name, such as mizzen topsail halyard, which describes its use.
List – The vessel’s angle of lean or tilt to one side, in the direction called roll.
Lubber’s line – A vertical line inside a compass case indicating the direction of the ship’s head.
Luff – The forward edge of a sail. To head a sailing vessel more towards the direction of the wind.
Luffing – When a sailing vessel is steered far enough to windward that the sail is no longer completely filled with wind (the luff of the sail is usually where this first becomes evident). Loosening a sheet so far past optimal trim that the sail is no longer completely filled with wind. The flapping of the sail(s) which results from having no wind in the sail at all.

M

Mainbrace – The brace attached to the mainmast.
Mainmast (or Main) – The tallest mast on a ship.
Mainsheet – Sail control line that allows the most obvious effect on mainsail trim. Primarily used to control the angle of the boom, and thereby the mainsail, this control can also increase or decrease downward tension on the boom while sailing upwind, significantly affecting sail shape. For more control over downward tension on the boom, use a boom vang.
Marina – a docking facility for small ships and yachts.
Mast – A vertical pole on a ship which supports sails or rigging.
Masthead – 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.
Master – Either the commander of commercial vessel, or a senior officer of a naval sailing ship in charge of routine seamanship and navigation but not in command during combat.
Matelot – A traditional Royal Navy term for an ordinary sailor.
Mess – An eating place aboard ship. A group of crew who live and feed together,
Mizzen staysail – Sail on a ketch or yawl, usually lightweight, set from, and forward of, the mizzen mast while reaching in light to moderate air.
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 (easily available in the form of foil used to seal e.g. tea chests from dampness) although Clifford W. Ashley notes that there was a “definite sporting limit” to the weight thus added.
Moor – to attach a boat to a mooring buoy or post. Also, to a dock a ship.

O

Oilskin Foul-weather gear worn by sailors.
Outhaul – A line used to control the shape of a sail.
Overfall – Dangerously steep and breaking seas due to opposing currents and wind in a shallow area.
Overreach – When tacking, to hold a course too long.

P

Parrel – A movable loop, used to fasten the yard to its respective mast.
Pilot – Navigator. A specially knowledgeable person qualified to navigate a vessel through difficult waters, e.g. harbour pilot etc.
Pitch – A vessel’s motion, rotating about the beam axis, so the bow pitches up and down.
Pitchpole – To capsize a boat end over end, rather than by rolling over.
Pontoon – A flat-bottomed vessel used as a ferry or a barge or float moored alongside a jetty or a ship to facilitate boarding.
Pooped – Swamped by a high, following sea. Exhausted.
Port – Towards the left-hand side of the ship facing forward (formerly Larboard). Denoted with a red light at night.
Preventer (Gybe preventer, Jibe preventer) – A 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.
Propeller walk or prop walk – tendency for a propeller to push the stern sideways. In theory a right hand propeller in reverse will walk the stern to port.

R

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 general, these fixtures will materially improve the visibility for use by vessels with radar.
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 centreline. 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.
Reach – 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 90°) and “broad reaching” (about 120° to 160°)
Red Duster – Traditional nickname for the Civil Red Ensign.
Reef – To temporarily reduce the area of a sail exposed to the wind, usually to guard against adverse effects of strong wind or to slow the vessel.
Rock or coral, possibly only revealed at low tide, shallow enough that the vessel will at least touch if not go aground.
Reef points – Small lengths of cord attached to a sail, used to secure the excess fabric after reefing.
Rigging – The system of masts and lines on ships and other sailing vessels.
Righting couple – The force which tends to restore a ship to equilibrium once a heel has altered the relationship between her centre of buoyancy and her centre of gravity.
Roll – A vessel’s motion rotating from side to side, about the fore-aft axis. List (qv) is a lasting tilt in the roll direction.
Running rigging – Rigging used to manipulate sails, spars, etc. in order to control the movement of the ship. Cf. standing rigging.

S

Sail-plan – A set of drawings showing various sail combinations recommended for use in various situations.
Sampson post – A strong vertical post used to support a ship’s windlass and the heel of a ship’s bowsprit.
Scandalize – To reduce the area of a sail by expedient means (slacking the peak and tricing up the tack) without properly reefing it.
Scuppers – An opening on the side rail that allows water to run off the deck.
Scuttlebutt – A barrel with a hole in used to hold water that sailors would drink from. Also: gossip.
Sea anchor – A stabilizer deployed in the water for heaving to in heavy weather. It acts as a brake and keeps the hull in line with the wind and perpendicular to waves.
Seaworthy – Certified for, and capable of, safely sailing at sea.
Sheer – The upward curve of a vessel’s longitudinal lines as viewed from the side.
Sheet – A rope used to control the setting of a sail in relation to the direction of the wind.
Ship – Strictly, a three-masted vessel square-rigged on all three masts, though generally used to describe most medium or large vessels. Derived from the Anglo-Saxon word ‘scip’.
Ship’s bell – Striking the ship’s bell is the traditional method of marking time and regulating the crew’s watches.
Ship’s company – The crew of a ship.
Shoal – Shallow water that is a hazard to navigation.
Shrouds – Standing rigging running from a mast to the sides of a ships.
Siren – A sound signal which uses electricity or compressed air to actuate either a disc or a cup shaped rotor.
Skipper – The captain of a ship.
Sonar – A sound-based device used to detect and range underwater targets and obstacles. Formerly known as ASDIC.
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 headsail.
Splice – To join lines (ropes, cables etc.) by unravelling their ends and intertwining them to form a continuous line. To form an eye or a knot by splicing.
Squat effect – Is 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.
Standing rigging – Rigging which is used to support masts and spars, and is not normally manipulated during normal operations. Cf. running rigging.
Starboard – Towards the right-hand side of a vessel facing forward. Denoted with a green light at night. Derived from the old steering oar or ‘steerboard’ which preceded the invention of the rudder.
Stay – Rigging running fore (forestay) and aft (backstay) from a mast to the hull.
Staysail – A sail whose luff is attached to a forestay.
Stem – The extension of keel at the forward of a ship.
Stern – The rear part of a ship, technically defined as the area built up over the sternpost, extending upwards from the counter to the taffrail.
Stern tube – The tube under the hull to bear the tailshaft for propulsion (usually at stern).
Strake – One of the overlapping boards in a clinker built hull.
Swinging the compass – Measuring the accuracy in a ship’s magnetic compass so its readings can be adjusted – often by turning the ship and taking bearings on reference points.
Swinging the lead – Measuring the depth of water beneath a ship using a lead-weighted sounding line. A sailor who was feigning illness etc to avoid a hard job was said to be ‘swinging the lead’.

T

Tailshaft – A kind of metallic shafting (a rod of metal) to hold the propeller and connected to the power engine. When the tailshaft is moved, the propeller may also be moved for propulsion.
Taken aback – An inattentive helmsmen might allow the dangerous situation to arise where the wind is blowing into the sails ‘backwards’, causing a sudden (and possibly dangerous) shift in the position of the sails.
Tally – The operation of hauling aft the sheets, or drawing them in the direction of the ship’s stern.
Three sheets to the wind – On a three-masted ship, having the sheets of the three lower courses loose will result in the ship meandering aimlessly downwind. Also, a sailor who has drunk strong spirits beyond his capacity.
Topsail – The second sail (counting from the bottom) up a mast. These may be either square sails or fore-and-aft ones, in which case they often “fill in” between the mast and the gaff of the sail below.
Topsides – the part of the hull between the waterline and the deck. Also, Above-water hull
Travellers – Small fittings that slide on a rod or line. The most common use is for the inboard end of the mainsheet; a more esoteric form of traveller consists of “slight iron rings, encircling the backstays, which are used for hoisting the top-gallant yards, and confining them to the backstays”.
Traffic separation scheme – Shipping corridors marked by buoys which separate incoming from outgoing vessels. Improperly called Sea Lanes.
Transom – a more or less flat surface across the stern of a vessel.
Trim – Relationship of ship’s hull to waterline.

U

Under way – A vessel that is not at anchor, or made fast to the shore, or aground.

V

Vanishing angle – The maximum degree of heel after which a vessel becomes unable to return to an upright position.

W

Wake – Turbulence behind a ship
Watch – A period of time during which a part of the crew is on duty. Changes of watch are marked by strokes on the ship’s bell.
Watercraft – Water transport vessels. Ships, boats, personal water craft.
Weather gage – Favourable position over another sailing vessel to with respect to the wind.
Weather deck – Whichever deck is that exposed to the weather – usually either the main deck or, in larger vessels, the upper deck.
Weather side – The weather side of a ship is the side exposed to the wind.
Weatherly – A ship that is easily sailed and manoeuvred; makes little leeway when sailing to windward.
Weigh anchor – To heave up (an anchor) preparatory to sailing.
Wells – Places in the ship’s hold for the pumps.
White horses – Waves in wind strong enough to produce foam or spray on the wave tops.
Wheelhouse – Location on a ship where the steering wheel is located, often interchanged with pilothouse and bridge.
Wide berth – To leave room between two ships moored (berthed) to allow space for manoeuvre.
Windage – Wind resistance of the boat.
Windward – In the direction that the wind is coming from.
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 small ships). Modern sailboats use an electric “Windlass” to raise the anchor.

Y

Yard – The horizontal spar from which a square sail is suspended.
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” and the sun being “over the yardarm” (late enough to have a drink).
Yaw – A vessel’s motion rotating about the vertical axis, so the bow yaws from side to side.
Yawl – A type of vessel