Glossary of nautical terms

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This is a partial glossary of nautical terms; some remain current, while many date from the 17th to 19th centuries. See also Wiktionary's nautical terms, Category:Nautical terms, and Nautical metaphors in English. See the Further reading section for additional words and references.

Contents :

A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
Y
See also
References
Further reading

A

A & AS: Alterations and additions to the structure, rigging and equipment of a warship.^[1]
Abaft: Toward the stern, relative to some object ("abaft the fore hatch").
Abaft the beam: Further aft than the beam: a relative bearing of greater than 90 degrees from the bow: "two points abaft the beam, starboard side". That would describe "an object lying 22.5 degrees toward the rear of the ship, as measured clockwise from a perpendicular line from the right side, center, of the ship, toward the horizon."^[2]
Abandon ship!: An imperative to leave the vessel immediately, usually in the face of some imminent overwhelming danger.^[3] It is an order issued by the Master or a delegated person in command. It is usually the last resort after all other mitigating actions have failed or become impossible, and destruction or loss of the ship is imminent; and customarily followed by a command to "man the lifeboats" or life rafts.^[3]^[4]
Abeam: On the beam, a relative bearing at right angles to the centerline of the ship's keel.; A sea shanty (song) about a young sailor trying to sleep with a maiden^[5]
Able Bodied Seaman: A merchant seaman qualified to perform all routine duties.
Aboard: On or in a vessel (see also close aboard).
About: "To go about is to change the course of a ship by tacking. Ready about, or boutship, is the order to prepare for tacking."^[6]
Above board: On or above the deck, in plain view, not hiding anything. Pirates would secret their crews below decks, thereby creating the false impression that an encounter with another ship was a casual matter of chance.^[7]
Above-water hull: The hull section of a vessel above the waterline, the visible part of a ship. Also, topsides.
Absentee pennant: Special pennant flown to indicate absence of commanding officer, admiral, his chief of staff, or officer whose flag is flying (division, squadron, or flotilla commander).
Absolute bearing: The bearing of an object in relation to north. Either true bearing, using the geographical or true north, or magnetic bearing, using magnetic north. See also bearing and relative bearing.
Accommodation ladder: A portable flight of steps down a ship's side.
Accommodation ship (or accommodation hulk): A ship or hulk used as housing, generally when there is a lack of quarters available ashore. An operational ship can be used, but more commonly a hulk modified for accommodation is used.
Act of Pardon or Act of Grace: A letter from a state or power authorising action by a privateer. Also see Letter of marque.
Admiral: Senior naval officer of Flag rank. In ascending order of seniority, Rear Admiral, Vice Admiral, Admiral and (until about 2001 when all UK five-star ranks were discontinued) Admiral of the Fleet (Royal Navy). Derivation Arabic, from Amir al-Bahr ("Ruler of the sea").
Admiralty: 1. A high naval authority in charge of a state's Navy or a major territorial component. In the Royal Navy (UK) the Board of Admiralty, executing the office of the Lord High Admiral, promulgates Naval law in the form of Queen's (or King's) Regulations and Admiralty Instructions.; 2. Admiralty law
Admiralty law: Body of law that deals with maritime cases. In the UK administered by the Probate, Divorce and Admiralty Division of the High Court of Justice or supreme court.
Adrift: Afloat and unattached in any way to the shore or seabed, but not under way. It implies that a vessel is not under control and therefore goes where the wind and current take her (loose from moorings, or out of place). Also refers to any gear not fastened down or put away properly. It can also apply generically to any person or thing that is misplaced or missing, e.g., "absent without leave".^[1]
Advance note: A note for one month's wages issued to sailors on their signing a ship's articles.
Adviso: See aviso.
Afloat: Of a vessel which is floating freely (not aground or sunk). More generally of vessels in service ("the company has 10 ships afloat").
Afore: 1. In, on, or toward the front of a vessel.; 2. In front of a vessel.
Aft: 1. The portion of the vessel behind the middle area of the vessel.; 2. Towards the stern (of the vessel).
Afternoon watch: The 1200–1600 watch.
Aground: Resting on or touching the ground or bottom (usually involuntarily).
Ahead: Forward of the bow.
Ahoy: A cry to draw attention. Term used to hail a boat or a ship, as "Boat ahoy!"
Ahull: 1. lying broadside to the sea.; 2. to ride out a storm with no sails and helm held to leeward.
Aid to Navigation: (ATON) Any device external to a vessel or aircraft specifically intended to assist navigators in determining their position or safe course, or to warn them of dangers or obstructions to navigation.
Aircraft carrier: A warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Since 1918, the term generally has been limited to a warship with an extensive flight deck designed to operate conventional fixed-wing aircraft. Also called a flat top.
Alee: 1. On the lee side of a ship.; 2. To leeward.
All hands: Entire ship's company, both officers and enlisted personnel.
All night in: Having no night watches.
All standing: Bringing a person or thing up short, that is an unforeseen and sudden stop.^[1]
Aloft: In the rigging of a sailing ship. Above the ship's uppermost solid structure; overhead or high above.; 1. In the rigging of a sailing ship.; 2. Above the ship's uppermost solid structure.; 3. Overhead or high above.
Alongside: By the side of a ship or pier.
Amidships: The middle section of a vessel with reference to the athwartships plane, as distinguished from port or starboard ("Put your rudder amidships.")
Anchor: 1. 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 or plough-like object designed to grip the bottom under the body of water (but also see sea anchor).; 2. to deploy an anchor ("She anchored offshore.")
Anchor ball: Round black shape hoisted in the forepart of a vessel to show that it is anchored.
Anchor buoy: A small buoy secured by a light line to an anchor to indicate position of anchor on bottom.
Anchor chain (or anchor cable): Chain connecting the ship to the anchor.
Anchor detail: Group of men who handle ground tackle when the ship is anchoring or getting under way.
Anchor home: When the anchor is secured for sea. Typically rests just outside the hawsepipe on the outer side of the hull, at the bow of a vessel.
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.
Anchor rode: The anchor line, rope or cable connecting the anchor chain to the vessel. Also Rode.
Anchor sentinel: A separate weight on a separate line which is loosely attached to the anchor rode so that it can slide down it easily. It is made fast at a distance slightly longer than the draft of the boat. It is used to prevent the anchor rode from becoming fouled on the keel or other underwater structures when the boat is resting at anchor and moving randomly during slack tide. Also called a kellet.
Anchor watch: The crewmen assigned to take care of the ship while anchored or moored, charged with such duties as making sure that the anchor is holding and the vessel is not drifting. Most marine GPS units have an Anchor Watch alarm capability.
Anchorage: A suitable place for a ship to anchor. Area of a port or harbor.
Anchor's aweigh: Said of an anchor when just clear of the bottom.
Andrew: Traditional lower-deck slang term for the Royal Navy.
Anti-rolling tanks: A pair of fluid-filled, usually water, tanks mounted on opposite sides of a ship below the waterline. Fluid would be pumped between them in an attempt to dampen the amount of roll.
Aport: Over to the port side.
Apparent wind: The combination of the true wind and the headwind caused by the boat's forward motion. For example, it causes a light side wind to appear to come from well ahead of the beam.
Arc of Visibility: The portion of the horizon over which a lighted aid to navigation is visible from seaward.
Archboard: The plank along the stern where the name of the ship is commonly painted.
Armament: A ship's weapons.
Articles of War: Regulations governing the military and naval forces of UK and USA; read to every ship's company on commissioning and at specified intervals during the commission.
As the crow flies: A direct line between two points (which might cross land) which is the way crows travel rather than ships which must go around land.
ASDIC: Purportedly an acronym. A type of sonar used by the Allies for detecting submarines during the First and Second World War. abbreviation: Allied Submarine Devices Investigation Committee (World War I). The term has been generically applied to equipment for "under-water supersonic echo-ranging equipment" of submarines and other vessels.^[8]
Ashore: 1. On the beach, shore, or land (as opposed to aboard or on board).; 2. Towards the shore.; 3. "To run ashore": To collide with the shore (as opposed to "to run aground," which is to strike a submerged feature such as a reef or sandbar)
Astarboard: Over to the starboard side.
Astern: 1. Toward the stern (rear) of a vessel.; 2. Behind a vessel.
Astern Gear: The gear or gears which, when engaged with an engine or motor, result in backwards movement or force. Equivalent to Reverse in a manual transmission automobile.
Asylum Harbour: A harbour used to provide shelter from a storm.
ASW: Anti-submarine warfare.
Athwart, athwartships: At right angles to the fore and aft or centerline of a ship.
Auxiliary ship (or auxiliary): A naval ship designed to operate in any number of roles supporting combatant ships and other naval operations, including a wide range of activities related to replenishment, transport, repair, harbor services, and research.
Avast: Stop, cease or desist from whatever is being done. From the Dutch hou' vast (“hold on”), the imperative form of vasthouden (“to hold on to”) or the Italian word "Basta"^[1] Compare ¡Ya basta!
Aviso (formerly also an adviso): A kind of dispatch boat or advice boat, survives particularly in the French navy, they are considered equivalent to the modern sloop.
Awash: So low in the water that the water is constantly washing across the surface.
Aweigh: Position of an anchor just clear of the bottom.
Axial fire: Fire oriented towards the ends of the ship; the opposite of broadside fire. In the age of sail this was known as 'raking' fire.
Aye, aye /ˌaɪ ˈaɪ/: Reply to an order or command to indicate that it, firstly, is heard; and, secondly, is understood and will be carried out. ("Aye, aye, sir" to officers). Also the proper reply from a hailed boat, to indicate that an officer is on board.
Azimuth circle: Instrument used to take bearings of celestial objects.
Azimuth compass: An instrument employed for ascertaining position of the sun with respect to magnetic north. The azimuth of an object is its bearing from the observer measured as an angle clockwise from true north.

B

Back and fill: To use the advantage of the tide being with you when the wind is not.
Backstays: Long lines or cables, reaching from the stern of the vessel to the mast heads, used to support the mast.
Baggywrinkle: A soft covering for cables (or any other obstructions) that prevents sail chafing from occurring.
Bailer: A device for removing water that has entered the boat.
Ballast tank: A device used on ships and submarines and other submersibles to control buoyancy and stability
Balls to four watch: The 0000–0400 watch. (US Navy)
Bank: A large area of elevated sea floor.
Banyan: Traditional Royal Navy term for a day or shorter period of rest and relaxation.
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 tranquility once inside. See also: touch and go, grounding. Alfred Lord Tennyson's poem "Crossing the bar" is an allegory for death.
Bar pilot: A bar pilot guides ships over the dangerous sandbars at the mouth of rivers and bays.
Barbette: 1. During the second half of the 19th century, a fixed armored enclosure protecting a ship‍ 's guns aboard warships without gun turrets, generally taking the form of a ring of armor over which guns mounted on an open-topped rotating turntable could fire.; 2. Since the late 19th century, the inside fixed trunk of a warship‍ 's turreted gun-mounting, on which the turret revolves, containing the hoists for shells and cordite from the shell-room and magazine.
Barca-longa: A two- or three-masted lugger used for fishing on the coasts of Spain and Portugal and more widely in the Mediterranean Sea in the late 17th century and 18th century. The British Royal Navy also used them for shore raids and as dispatch boats in the Mediterranean.
Bareboat charter: An arrangement for the chartering or hiring of a vessel, whereby the vessel‍ 's owner provides no crew or provisions as part of the agreement; instead, the people who rent the vessel are responsible for crewing and provisioning her.
Barge: 1. A towed or self-propelled flat-bottomed boat, built mainly for river, canal, and coastal transport of heavy goods.; 2. Admiral‍ 's barge: A boat at the disposal of an admiral for his or her use as transportation between a larger vessel and the shore or within a harbor.
Bark: Alternative spelling of barque.
Barkentine: Alternative spelling of barquentine.
Barque (also bark): A sailing vessel of three or more masts, with all masts but the sternmost square-rigged, the sternmost being fore-and-aft-rigged.
Barquentine (also barkentine): A sailing vessel with three or more masts; with a square-rigged foremast and all other masts fore-and-aft rigged.
Barrack ship: A ship or craft designed to function as a floating barracks for housing military personnel.
Barrelman: A sailor that was stationed in the crow's nest.
Batten: 1. A stiff strip used to support the roach of a sail, enabling increased sail area.; 2. Any thin strip of material (wood, plastic etc) which can be used any number of ways
Batten down the hatches: To prepare for inclement weather by securing the closed hatch covers with wooden battens so as to prevent water from entering from any angle.
Battlecruiser: A type of large capital ship of the first half of the 20th century, similar in size, appearance, and cost to a battleship and typically armed with the same kind of heavy guns, but much more lightly armored (on the scale of cruiser) and therefore faster than a battleship but more vulnerable to damage.
Battleship: A type of large, heavily armored warship of the second half of the 19th century and first half of the 20th century armed with heavy-caliber guns, designed to fight other battleships in a line of battle. It was the successor to the ship-of-the-line of the Age of Sail.
Beaching: Deliberately running a vessel aground to load and unload (as with landing craft), or sometimes to prevent a damaged vessel sinking.
Beacon: A lighted or unlighted fixed aid to navigation attached directly to the earth’s surface. (Lights and daybeacons both constitute beacons.)
Beakhead: The ram on the prow of a fighting galley of ancient and medieval times.); 2. The protruding part of the foremost section of a sailing ship of the 16th to the 18th century, usually ornate, used as a working platform by sailors handling the sails of the bowsprit. It also housed the crew‍ 's heads (toilets).
Beam: The width of a vessel at the widest point, or a point alongside the ship at the midpoint of its length.
Beam ends: The sides of a ship. "On her beam ends" may mean the vessel is literally on her side and possibly about to capsize; more often, the phrase means the vessel is listing 45 degrees or more.
Beam reach: Sailing with the wind coming across the vessel's beam.
Beam sea: A sea where waves are moving perpendicular to the direction a ship is moving
Beam wind: A wind at right angles to the vessel's course.
Bear: Large squared off stone used with sand for scraping clean wooden decks.
Bear away: To steer (a vessel) away from the wind.
Bear down or 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. See also absolute bearing and relative bearing.
Beating or Beat to: 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)
Beat to quarters: Prepare for battle (beat = beat the drum to signal the need for battle preparation)
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.
Becalm: To cut off the wind from a sailing vessel, either by the proximity of land or by another vessel.
Becalmed: Unable to move due to lack of wind; said of a sailing vessel.
Before the mast: Literally, the area of a ship before the foremast (the forecastle). Most often used to refer to men whose living quarters are located here, officers being quartered in the stern-most areas of the ship (near the quarterdeck). Officer-trainees lived between the two ends of the ship and become known as "midshipmen". Crew members who started out as seamen, then became midshipmen, and later, officers, were said to have gone from "one end of the ship to the other" (also see hawsepiper).
Belay: 1. To make fast a line around a fitting, usually a cleat or belaying pin.; 2. To secure a climbing person in a similar manner.; 3. An order to halt a current activity or countermand an order prior to execution.
Belaying pins: Short movable bars of iron or hard wood to which running rigging may be secured, or belayed.
Bell: A type of buoy with a large bell and hanging hammers that sound by wave action. (see also ship’s bell).
Belt armor: A layer of heavy metal armor plated onto or within the outer hulls of warships, typically on battleships, battlecruisers, cruisers, and aircraft carriers, usually covering the warship from her main deck down to some distance below the waterline. If built within the hull, rather than forming the outer hull, the belt would be installed at an inclined angle to improve the warship‍ 's protection from shells striking the hull.
Bend: A knot used to join two ropes or lines. See also hitch.
Bermuda rig or Bermudan rig: A triangular mainsail, without any 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.
Bermuda sloop: A fore-and-aft rigged sailing vessel with Bermuda rig developed in Bermuda in the 17th century. In its purest form, it is single-masted, although Bermuda sloops can have up to three masts, three-masted ships being referred to as schooners. Originally gaff rigged, but evolved to use Bermuda rig. The Bermuda sloop is the basis of nearly all modern sailing yachts.
Berth (moorings): A location in a port or harbour used specifically for mooring vessels while not at sea.
Berth (navigation): Safety margin of distance to be kept by a vessel from another vessel or from an obstruction, hence the phrase, "to give a wide berth."^[9]
Berth (sleeping): A bed or sleeping accommodation on a boat or ship.
Best bower (anchor): The larger of two anchors carried in the bow; so named as it was the last, best hope.
Between the devil and the deep blue sea: See devil seam.
Between wind and water: The part of a ship's hull that is sometimes submerged and sometimes brought above water by the rolling of the vessel.
Bight /ˈbaɪt/: 1. Bight, a loop in rope or line—a hitch or knot tied on the bight is one tied in the middle of a rope, without access to the ends.; 2. An indentation in a coastline.
Bilander (also billander or be‍ 'landre): a small European merchant sailing ship with two masts, the mainmast lateen-rigged with a trapezoidal mainsail, and the foremast carrying the conventional square course and square topsail. Used in the Netherlands for coast and canal traffic and occasionally in the North Sea, but more frequently used in the Mediterranean Sea.
Bilge: The compartment at the bottom of the hull of a ship or boat where water collects and must be pumped out of the vessel.
Bilge keels: A pair of keels on either side of the hull, usually slanted outwards. In yachts, they allow the use of a drying mooring, the boat standing upright on the keels (and often a skeg) when the tide is out.
Bilged on her anchor: A ship that has run upon her own anchor, so the anchor cable runs under the hull.
Bill: The extremity of the arm of an anchor; the point of or beyond the fluke.
Bimini top: Open-front canvas top for the cockpit of a boat, usually supported by a metal frame.
Bimmy: A punitive instrument
Binnacle: The stand on which the ship's compass is mounted.
Binnacle list: A ship's sick list. The list of men unable to report for duty was given to the officer or mate of the watch by the ship's surgeon. The list was kept at the binnacle.
Bite: Verb used in reference to a rudder, as in "the rudder begins to bite." When a vessel has steerageway the rudder will act to steer the vessel, i.e. it has enough water flow past it to steer with. Physically this is noticeable with tiller or unassisted wheel steering by the rudder exhibiting resistance to being turned from the straight ahead - this resistance is the rudder "biting" and is how a helmsman first senses that the vessel has acquired steerageway.
Bitt or bitts: A post or pair mounted on the ship's bow, for fastening ropes or cables.
Bitter end: The last part or loose end of a rope or cable. The anchor cable is tied to the bitts; when the cable is fully paid out, the bitter end has been reached.
Black gang: The engineering crew of the vessel, i.e., crewmembers who work in the vessel‍ 's engine room, fire room, and boiler room, so called because they would be covered in coal dust during the days of coal-fired steamships.
Block: A pulley or set of pulleys.
Blue Peter: A blue and white flag (the flag for the letter "P") hoisted at the foretrucks of ships about to sail. Formerly a white ship on a blue ground, but later a white square on a blue ground.
Boat: 1. A small craft or vessel designed to float on, and provide transport over, or under, water.; 2. Naval slang for a submarine of any size.
Boat-hook: A pole with a hook on the end, used to reach into the water to catch buoys or other floating objects.
Boatswain or bosun (both /ˈboʊsən/): A non-commissioned officer responsible for the sails, ropes, rigging and boats on a ship who issues "piped" commands to seamen.
Boatswain's call, also bosun's call, boatswain's pipe, bosun's pipe, boatswain's whistle, or bosun's whistle: A high-pitched pipe or a non-diaphragm-type whistle used on naval ships by a boatswain, historically to pass commands to the crew but in modern times limited to ceremonial use.
Boatswain's chair or bosun's chair: A short board or swatch of heavy canvas, secured in a bridle of ropes, used to hoist a man aloft or over the ship’s side for painting and similar work. Modern boatswain's chairs incorporate safety harnesses to prevent the occupant from falling.
Boatswain's pipe: See boatswain's call.
Boatswain's whistle: See boatswain's call.
Boatwright: A maker of boats, especially of traditional wooden construction.
Bobstay: A stay which holds the bowsprit downwards, counteracting the effect of the forestay. Usually made of wire or chain to eliminate stretch.
Body plan: In shipbuilding, an end elevation showing the contour of the sides of a ship at certain points of her length.
Bollard: From "bol" or "bole", the round trunk of a tree. A substantial vertical pillar to which lines may be made fast. Generally on the quayside rather than the ship.
Bombay runner: Large cockroach.
Bonded jacky: A type of tobacco or sweet cake.
Bonnet: A strip of canvas secured to the foot of the course (square sail) to increase sail area in light airs.
Booby: A type of bird that has little fear and therefore is particularly easy to catch.
Booby hatch: A sliding hatch or cover.
Boom (navigational barrier): A floating barrier to control navigation into and out of rivers and harbours.
Boom (sailing): A spar attached to the foot of a fore-and-aft sail.
Boom gallows: A raised crossmember that supports a boom when the sail is lowered (obviates the need for a topping lift).
Boom vang or vang: A sail control that lets one apply downward tension on a boom, countering the upward tension provided by the sail. The boom vang adds an element of control to sail shape when the sheet 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.
Boomkin: See bumpkin.
Booms: Masts or yards, lying on board in reserve.
Bore : i.e.Bore up or Bore away: To assume a position to engage, or disengage, the enemy ship(s)
Bosun: See boatswain.
Bosun's call: See boatswain's call.
Bosun's chair: See boatswain's chair.
Bosun's pipe: See boatswain's call.
Bosun's whistle: See boatswain's call.
Bottlescrew: A device for adjusting tension in stays, shrouds and similar lines.
Bottom: 1. The underside of a vessel; the portion of a vessel that is always underwater; .; 2. A ship, most often a cargo ship.; 3. A cargo hold.
Bottomry: Pledging a ship as security in a financial transaction.
Bow: 1. The front of a vessel.; 2. Either side of the front (or bow) of the vessel, i.e., the port bow and starboard bow. Something ahead and to the left of the vessel is "off the port bow", while something ahead and to the right of the vessel is "off the starboard bow." When "bow" is used in this way, the front of the vessel sometimes is called her bows (plural), a collective reference to her port and starboard bows synonymous with bow (singular) as described in Definition (1).
Bow chaser: See chase gun
Bow thruster: A small propeller or water-jet at the bow, used for manoeuvring larger vessels at slow speed. May be mounted externally, or in a tunnel running through the bow from side to side.
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).
Bowse: To pull or hoist.
Bowsprit: A spar projecting from the bow used as an anchor for the forestay and other rigging.
Boxing the compass: To state all 32 points of the compass, starting at north, proceeding clockwise. Sometimes applied to a wind that is constantly shifting.
Boy Seaman: a young sailor, still in training
Brace abox: To bring the foreyards flat aback to stop the ship.
Brail: To furl or truss a sail by pulling it in towards the mast, or the ropes used to do so.
Brake: The handle of the pump, by which it is worked.
Brass monkey or brass monkey weather: Used in the expression "it is cold enough to freeze the balls off a brass monkey."
Brass pounder: Early 20th-century slang term for a vessel‍ 's radio operator, so called because he repeatedly struck a brass key on his transmitter to broadcast in Morse code.
Break bulk cargo (or breakbulk cargo): Goods that must be loaded aboard a ship individually, and not in intermodal containers or in bulk, carried by a general cargo ship.
Breakwater: 1. A structure constructed on a coast as part of a coastal defense system or to protect an anchorage from the effects of weather and longshore drift.; 2. A structure built on the forecastle of a ship intended to divert water away from the forward superstructure or gun mounts.
Breeches buoy: A ring lifebuoy fitted with canvas breeches, functionally similar to a zip line, used to transfer people from one ship to another or to rescue people from a wrecked or sinking ship by moving them to another ship or to the shore.
Bridge: A structure above the weather deck, extending the full width of the vessel, which houses a command centre, itself called by association, the bridge.
Bridge wing: An open-air extension of the bridge to port or starboard, intended for use in signaling.
Brig: 1. (historically) A vessel with two square-rigged masts.; 2. (in the US) An interior area of the ship used to detain prisoners (possibily prisoners-of-war, in war-time) & stowaways, and to punish delinquent crew members. Usually resembles a prison-cell with bars and a locked, hinged door.
Brig sloop: A type of sloop-of-war introduced in the 1770s which had two square-rigged masts like a brig (in contrast to ship sloops of the time, which had three masts).
Brigantine (also hermaphrodite brig): A two-masted vessel, square-rigged on the foremast, but fore-and-aft-rigged on the mainmast.
Brightwork: Exposed varnished wood or polished metal on a boat.
Bring to: Cause a ship to be stationary by arranging the sails.
Broach: When a sailing vessel loses control of its motion and is forced into a sudden sharp turn, often heeling heavily and in smaller vessels sometimes leading to a capsize. The change in direction is called broaching-to. Occurs when too much sail is set for a strong gust of wind, or in circumstances where the sails are unstable.
Broad: Wide (broad) in appearance from the vantage point of a lookout or other person viewing activity in the vicinity of a ship, e.g., another ship off the starboard bow with her side facing the viewer's ship could be described as "broad on the starboard bow" of the viewer's ship.
Broadside: 1. One side of a vessel above the waterline.; 2. All the guns on one side of a warship or mounted (in rotating turrets or barbettes) so as to be able fire on the same side of a warship.; 3. The simultaneous firing of all the guns on one side of warship or able to fire on the same side of a warship.; 4. Weight of broadside, the combined weight of all projectiles a ship can fire in a broadside, or the combined weight of all the shells a group of ships that have formed a line of battle collectively can fire on the same side.
Brow: See gangplank.
Buffer: The chief bosun's mate (in the Royal Navy), responsible for discipline.
Bulbous bow: A protruding bulb at the bow of a ship just below the waterline which modifies the way water flows around the hull, reducing drag and thus increasing speed, range, fuel efficiency, and stability.
Bulk cargo: Commodity cargo that is transported unpackaged in large quantities.
Bulk carrier (also bulk freighter or bulker): A merchant ship specially designed to transport unpackaged bulk cargo in its cargo holds.
Bulkhead: An upright wall within the hull of a ship. Particularly a watertight, load-bearing wall.
Bulwark or Bulward (/ˈbʊlək/ in nautical use): Bulwark (or Bulward)
The extension of the ship's side above the level of the weather deck.
Bumboat: A private boat selling goods.
Bumpkin or boomkin: 1. A spar, similar to a bowsprit, but which projects from the stern. 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.
Bunker: A container for storing coal or fuel oil for a ship‍ 's engine.
Bunker fuel or bunkers: Fuel oil for a ship.
Bunting tosser: A signalman who prepares and flies flag hoists. Also known in the American Navy as a skivvy waver.
Buntline: One of the lines tied to the bottom of a square sail and used to haul it up to the yard when furling.
Buoy: A floating object of defined shape and color, which is anchored at a given position and serves as an aid to navigation.
Buoyed up: Lifted by a buoy, especially a cable that has been lifted to prevent it from trailing on the bottom.
Burden (Early Modern English: Burthen, Middle English: Byrthen): The Builder's Old Measurement, expressed in "tons bm" or "tons BOM", a volumetric measurement of cubic cargo capacity, not of weight. This is the tonnage of a ship, based on the number of tuns of wine that it could carry in its holds. One 252-gallon tun of wine takes up approximately 100 cubic feet – and, incidentally, weighs 2,240 lbs (1 long ton, or Imperial ton).
Burgee: A small flag, typically triangular, flown from the masthead of a yacht to indicate yacht-club membership.
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

Cabin: an enclosed room on a deck or flat.
Cabin boy: attendant on passengers and crew. often a young man
Cable: A large rope.
Cable length: 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.
Caboose: a small ship's kitchen, or galley on deck.
Camels: Loaded vessels lashed tightly, one on each side of another vessel, and then emptied to provide additional buoyancy that reduces the draught of the ship in the middle.
Can: A type of navigational buoy often a vertical drum, but if not, always square in silhouette, colored red in IALA region A or green in IALA region B (the Americas, Japan, Korea and the Philippines). In channel marking its use is opposite that of a "nun buoy".
Canal boat: A specialized watercraft designed for operation on a canal.
Canister: a type of antipersonnel cannon load in which lead balls or other loose metallic items were enclosed in a tin or iron shell. On firing, the shell would disintegrate, releasing the smaller metal objects with a shotgun-like effect.
Canoe stern: A design for the stern of a yacht which is pointed, like a bow, rather than squared off as a transom.
Cape Horn fever: The name of the fake illness a malingerer is pretending to suffer from.
Capital ship: A navy‍ 's most important warships, generally possessing the heaviest firepower and armor and traditionally much larger than other naval vessels, but not formally defined. During the Age of Sail, generally understood to be ships-of-the-line; during the second half of the 19th century and the 20th century, understood to be battleships and battlecruisers; and since the 1940s considered to include aircraft carriers. Since the second half of the 20th century, ballistic missile submarines sometimes have been considered capital ships.
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. Compare Turtling, infra.
Capstan: A large winch with a vertical axis. A full-sized human-powered capstan is a waist-high cylindrical machine, operated by a number of hands who each insert a horizontal capstan bar in holes in the capstan and walk in a circle. Used to wind in anchors or other heavy objects; and sometimes to administer flogging over.
Captain: 1. The person lawfully in command of a vessel. "Captain" is an informal title of respect given to the commander of a naval vessel regardless of his or her formal rank; aboard a merchant ship, the ship‍ 's master is her "captain."; 2. A naval officer with a rank between commander and commodore.; 3. In the United States Navy, United States Coast Guard, and National Oceanic and Atmospheric Administration Corps, a commissioned officer of a grade superior to a commander and junior to a rear admiral (lower half), equal in grade or rank to a United States Army, United States Marine Corps, or United States Air Force colonel.
Captain of the Port: 1. In the United Kingdom, a Royal Navy officer, usually a captain, responsible for the day-to-day operation of a naval dockyard.; 2. In the United States, a United States Coast Guard officer, usually a captain, responsible for enforcement of safety, security, and marine environmental protection regulations in a commercial port.
Captain's daughter: The cat o' nine tails, which in principle is only used on board on the captain's (or a court martial's) personal orders.
Car float (also railroad car float or rail barge): An unpowered barge with railroad tracks mounted on its deck, used to move railroad cars across water obstacles.
Caravel (also caravelle): A small, highly maneuverable sailing ship with lateen rig used by the Portuguese in the 15th and 16th centuries to explore along the West African coast and into the Atlantic Ocean.
Cardinal: Referring to the four main points of the compass: north, south, east and west. See also bearing.
Careening: Tilting a ship on its side, usually when beached, to clean or repair the hull below the water line. Also known as to "heave down".
Cargo ship: Any sort of ship or vessel that carries cargo, goods, and materials from one port to another, including general cargo ships (designed to carry break bulk cargo), bulk carriers, container ships, multipurpose vessels, and tankers. Tankers, however, although technically cargo ships, are routinely thought of as constituting a completely separate category.
Carpenter: 1. In the Age of Sail, a warrant officer responsible for the hull, masts, spars, and boats of a vessel, and whose responsibility was to sound the well to see if the vessel was making water.; 2. A senior rating responsible for all the woodwork aboard a vessel.
Carrack (also nau): A three- or four-masted sailing ship used by Western Europeans in the Atlantic Ocean from the 15th through the early 17th century.
Carvel built: A method of constructing wooden hulls by fixing planks to a frame so that the planks butt up against each other. Cf. "clinker built".
Cat: 1. To prepare an anchor, after raising it by lifting it with a tackle to the cat head, prior to securing (fishing) it alongside for sea. (An anchor raised to the cat head is said to be catted.); 2. The cat o' nine tails (see below).; 3. A cat-rigged boat or catboat.
Cat o' nine tails: A 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, this is a possible origin for the term "cat out of the bag," though livestock trade was more likely^[10] where this phrase came from. "Not enough room to swing a cat" also derives from this.
Catamaran: A vessel with two hulls.
Catboat: A cat-rigged vessel with a single mast mounted close to the bow, and only one sail, usually on a gaff.
Catharpin: A short rope or iron clamp used to brace in the shrouds toward the masts so as to give a freer sweep to the yards.
Cathead: A beam extending out from the hull used to support an anchor when raised in order to secure or 'fish' it.
Cats paws: Light variable winds on calm waters producing scattered areas of small waves.
Center of effort (or centre of effort): The point of origin of net aerodynamic force on sails, roughly located in the geometric center of a sail, but the actual position of the center of effort will vary with sail plan, sail trim or airfoil profile, boat trim, and point of sail. Also known as center (or centre) of pressure
Centerline (or centerline): An imaginary line down the center of a vessel lengthwise. Any structure or anything mounted or carried on a vessel that straddles this line and is equidistant from either side of the vessel is on the centerline (or centreline).
Centreboard (or centerboard): A board or plate lowered through the hull of a dinghy on the centreline to resist leeway.
Chafing: Wear on line or sail caused by constant rubbing against another surface.
Chafing gear: Material applied to a line or spar to prevent or reduce chafing. See Baggywrinkle.
Chain locker: A space in the forward part of the ship, typically beneath the bow in front of the foremost collision bulkhead, that contains the anchor chain when the anchor is secured for sea.
Chain-shot: Cannon balls linked with chain used to damage rigging and masts.
Chain-wale or channel: A broad, thick plank that projects horizontally from each of a ship's sides abreast a mast, distinguished as the fore, main, or mizzen channel accordingly, serving to extend the base for the shrouds, which supports the mast.
Chains: Small platforms built into the sides of a ship to assist in depth sounding.
Charley Noble: The metal stovepipe chimney from a cook shack on the deck of a ship or from a stove in a galley .
Charthouse: A compartment, especially in the Royal Navy, from which the ship was navigated.
Chase gun, chase piece, or chaser: A cannon pointing forward or aft, often of longer range than other guns. Those on the bow (bow chaser) were used to fire upon a ship ahead, while those on the rear (stern chaser) were used to ward off pursuing vessels. Unlike guns pointing to the side, chasers could be brought to bear in a chase without slowing.
Cheeks: 1. Wooden blocks at the side of a spar.; 2. The sides of a block or gun-carriage.
Chine: 1. An angle in the hull.; 2. A line formed where the sides of a boat meet the bottom. Soft chine is when the two sides join at a shallow angle, and hard chine is when they join at a steep angle.
Chock: Hole or ring attached to the hull to guide a line via that point
Chock-a-block: Rigging blocks that are so tight against one another that they cannot be further tightened.
Chronometer: A timekeeper accurate enough to be used to determine longitude by means of celestial navigation.
Cigarette boat: see go-fast boat.
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. Colloquially called the "red duster".
Class: 1. A group of naval ships of the same or similar design.; 2. A standard of construction for merchant vessels, including standards for specific types or specialized capabilities of some types of merchant vessels. A ship meeting the standard is in class, one not meeting them is out of class.
Clean bill of health: A certificate issued by a port indicating that the ship carries no infectious diseases. Also called a pratique.
Clean slate: At the helm, the watch keeper would record details of speed, distances, headings, etc. on a slate. At the beginning of a new watch the slate would be wiped clean.
Clear: To perform customs and immigration legalities prior to leaving port.
Cleat: A stationary device used to secure a rope aboard a vessel.
Clench: A method of fixing together two pieces of wood, usually overlapping planks, by driving a nail through both planks as well as a washer-like rove. The nail is then burred or riveted over to complete the fastening.
Clew: The lower corners of square sails or the corner of a triangular sail at the end of the boom.
Clew-lines: Used to truss up the clews, the lower corners of square sails.
Clinker built: A method of constructing hulls that involves overlapping planks, and/or plates, much like Viking longships, resulting in speed and flexibility in small boat hulls. Cf. "carvel built".
Clipper: A very fast sailing ship of the 19th century that had three or more masts, a square rig, a long, low hull, and a sharply raked stem.
Close aboard: Near a ship.
Close-hauled: Of a vessel beating as close to the wind direction as possible.
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. See kedge.
Coal hulk: A hulk used to store coal.
Coal trimmer, or Trimmer: person responsible for ensuring that a coal-fired vessel remains in 'trim' (evenly balanced) as coal is consumed on a voyage.
Coaming: The raised edge of a hatch, cockpit or skylight to help keep out water.
Coaster (or coastal trading vessel): A shallow-hulled ship used for trade between locations on the same island or continent.
Cockpit: The seating area (not to be confused with Deck). The area towards the stern of a small decked vessel that houses the rudder controls.
Cog: A type of sailing ship with a single mast and square-rigged single sail first developed in the 10th century and widely used, particularly in the Baltic Sea region, in seagoing trade from the 12th through the 14th century.
Collier: A bulk cargo ship designed to carry coal, especially such a ship in naval use to supply coal to coal-fired warships.
Comber: A long, curving wave breaking on the shore.
Come about: 1. To tack.; 2. To change tack.; 3. To maneuver the bow of a sailing vessel across the wind so that the wind changes from one side of the vessel to the other.; 4. To position a vessel with respect to the wind after tacking.
Come to: To stop a sailing vessel, especially by turning into the wind.
Commission: To formally place (a naval vessel) into active service, after which the vessel is said to be in commission. Sometimes used less formally to mean placing a commercial ship into service.
Commodore: 1. Commodore (rank), a military rank used in many navies that is superior to a navy captain, but below a rear admiral. Often equivalent to the rank of "flotilla admiral" or sometimes "counter admiral" in non-English-speaking navies.; 2. Convoy Commodore, a civilian put in charge of the good order of the merchant ships in British convoys during World War II, but with no authority over naval ships escorting the convoy.; 3. Commodore (yacht club), an officer of a yacht club.; 4. Commodore (Sea Scouts), a position in the Boy Scouts of America's Sea Scout program.
Communication tube, speaking tube, or voice tube: An air-filled tube, usually armored, allowing speech between the conning tower with the below-decks control spaces in a warship.
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 showing the direction of the vessel in relation to the Earth's geographical poles or magnetic poles. Commonly consists of a magnet aligned with the Earth's magnetic field, but other technologies have also been developed, such as the gyrocompass.
Complement: The number of persons in a ship‍ 's crew, including officers.
Comprise: To include or contain: As applied to a naval task force, the listing of all assigned units for a single transient purpose (mission). “The Task Force comprises Ship A, Ship B, and Ship C.” ‘Comprise’ means exhaustive inclusion – there aren't any other parts to the task force, and each ship has a permanent squadron existence, independent of the task force.
Conn: (Also written con, conne, conde, cunde, or cun) To direct a ship or submarine from a position of command. While performing this duty, an officer is said to have the conn.
Conning officer: An officer on a naval vessel responsible for instructing the helmsman on the course to steer. While performing this duty, the officer is said to have the conn.
Conning tower: 1. The armoured control tower of an iron or steel warship built between the mid-19th and mid-20th centuries from which the ship was navigated in battle.; 2. A tower-like structure on the dorsal (topside) surface of a submarine, serving in submarines built before the mid-20th century as a connecting structure between the bridge and pressure hull and housing instruments and controls from which the periscopes were used to direct the submarine and launch torpedo attacks. Since the mid-20th century, it has been replaced by the sail (United States usage) or fin (European and British Commonwealth usage), a structure similar in appearance which no longer plays a function in directing the submarine.
Consort: Unpowered Great Lakes vessels, usually a fully loaded schooner, barge, or steamer barge, towed by a larger steamer that would often tow more than one barge. The consort system was used in the Great Lakes from the 1860s to around 1920.
Constant bearing, decreasing range (CBDR): When two boats are approaching each other from any angle and this angle remains the same over time (constant bearing) they are on a collision course. Because of the implication of disaster (ships might collide) it has come to mean a problem or an obstacle which is heading your way. Often used in the sense of a warning, as in "watch out for this problem you might not see coming."^[11]
Container ship: A cargo ship that carries all of her cargo in truck-size intermodal containers.
Convoy: A group of ships traveling together for mutual support and protection.
Corinthian: An amateur yachter.^[12]^[13]
Corrector: A device to correct the ship's compass, for example counteracting errors due to the magnetic effects of a steel hull.
Corsair: 1. A French privateer, especially from the port of St-Malo.; 2. Any privateer or pirate.; 3. A ship used by privateers or pirates, especially of French nationality.; 4. Corsair, a class of 16-foot (4.9-meter) three-handed sailing dinghy.
Corvette: 1. A flush-decked sailing warship of the 17th, 18th, and 19th centuries having a single tier of guns, ranked next below a frigate. Called in the United States Navy a sloop-of-war.; 2. A lightly armed and armored warship of the 20th and 21st centuries, smaller than a frigate, capable of trans-oceanic duty.
Counter: The part of the stern above the waterline that extends beyond the rudder stock culminating in a small transom. A long counter increases the waterline length when the boat is heeled, so increasing hull speed.
Counterflood: To deliberately flood compartments on the opposite side from already flooded ones. Usually done to reduce a list.
Course: The direction in which a vessel is being steered, usually given in degrees.
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).
Cowl: 1. A ship‍ 's ventilator with a bell-shaped top which can be swivelled to catch the wind and force it below.; 2. A vertical projection of a ship‍ 's funnel which directs the smoke away from the bridge.
Coxswain or cockswain /ˈkɒksən/: The helmsman or crew member in command of a boat.
Crance/Crans/Cranze iron: A fitting, mounted at the end of a bowsprit to which stays are attached.
Crane vessel or crane ship: A ship with a crane specialized in lifting heavy loads.
Crazy Ivan: United States Navy slang for a maneuver in which a submerged Soviet or Russian submarine suddenly turns 180 degrees or through 360 degrees to detect submarines following it.
Crew: 1. On warships and merchant ships, those members of a ship's company who are not officers; 2. On leisure vessels with no formal chain of command, those persons who are not the skipper (q.v.) or passengers.
Cringle: A rope loop, usually at the corners of a sail, for fixing the sail to a spar. They are often reinforced with a metal eye.
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: two horizontal struts at the upper ends of the topmasts of sailboats, used to anchor the shrouds from the topgallant mast.
Crow flies, as the: see as the crow flies.
Crow's nest: Specifically a masthead constructed with sides and sometimes a roof to shelter the lookouts from the weather, generally by whaling vessels, this has become a generic term for what is properly called masthead. See masthead.
Cruise ship: A passenger ship used for pleasure voyages, where the voyage itself and the ship's amenities are part of the experience, as well as the different destinations along the way. Transportation is not the prime purpose, as cruise ships operate mostly on routes that return passengers to their originating port. A cruise ship contrasts with a passenger liner, which is a passenger ship that provides a scheduled service between published ports primarily as a mode of transportation. Large, prestigious passenger ships used for either purpose sometimes are called ocean liners.
Cruiser: 1. From the mid-19th century to the mid-20th century, a classification for a wide variety of gun- and sometimes torpedo-armed warships, usually but not always armored, intended for independent scouting, raiding, or commerce protection; some were designed also to provide direct support to a battlefleet. Cruisers carried out functions performed previously by the cruising ships (sailing frigates and sloops) of the Age of Sail.; 2. From the early 20th century to the mid-20th century, a type of armored warship with varying armament and of various sizes, but always smaller than a battleship and larger than a destroyer, capable of both direct support of a battle fleet and independent operations, armed with guns and sometimes torpedoes.; 3. After the mid-20th century, various types of warships of intermediate size armed with guided missiles and sometimes guns, intended for air defense of aircraft carriers and associated task forces or for anti-ship missile attack against such forces; virtually indistinguishable from large destroyers since the late 20th century.
Crutches: Metal Y shaped pins to hold oars whilst rowing.
Cuddy: A small cabin in a boat; a cabin, for the use of the captain, in the after part of a sailing ship under the poop deck.
Cunningham: A line invented by Briggs Cunningham, used to control the shape of a sail.
Cunt splice or cut 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.
Cuntline: The "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.
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 one. Also used figuratively of people.^[14]
Cutter: 1. A small single-masted boat, fore-and-aft rigged, with two or more headsails and often a bowsprit. The mast is set farther back than on a sloop.; 2. A small boat serving a larger vessel, used to ferry passengers or light stores between larger vessels and the shore.; 3. In the 20th and 21st centuries, a small- or medium-sized vessel whose occupants exercise official authority, such as harbor pilots' cutters, United States Coast Guard Cutters, and UK Border Agency cutters.

D

Daggerboard: A type of light centerboard that is lifted vertically; often in pairs, with the leeward one lowered when beating.
Davit: 1. A spar formerly used on board ships as a crane to hoist the flukes of the anchor to the top of the bow, without injuring the sides of the ship.; 2. A crane, often working in pairs and usually made of steel, used to lower things over the side of a ship, including launching a lifeboat over the side of a ship.
Davy Jones' Locker: An idiom for the bottom of the sea.
Day beacon: An unlighted fixed structure which is equipped with a dayboard for daytime identification.
Day-blink: Moment at dawn where, from some point on the mast, a lookout can see above low lying mist which envelops the ship.
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).
Dead ahead: Exactly ahead, directly ahead, directly in front.
Dead in the water: Not moving (used only when a vessel is afloat and neither tied up nor anchored).
Dead run: See running.
Deadeye: A wooden block with holes (but no pulleys) which is spliced to a shroud. It is used to adjust the tension in the standing rigging of large sailing vessels, by lacing through the holes with a lanyard to the deck. Performs the same job as a turnbuckle.
Deadlight: A strong shutter fitted over a porthole or other opening that can be closed in bad weather.
Deadrise: The design angle between the keel (q.v.) and horizontal.
Deadwood: A wooden part (vertical timbers or planking) of the centerline structure of a boat, usually between the sternpost and amidships. It is used to "fill the spaces where, owing to the shape of the vessel, the floor-timbers have to be discontinued."^[15]^[16]
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. During a death roll, the boat rolls from side to side, becoming gradually more unstable until either it capsizes or the skipper reacts correctly to prevent it.
Debarcation or disembarkation: The process of leaving a ship or aircraft, or removing goods from a ship or aircraft.
Decks: The top of the boat; the surface is removed to accommodate the seating area. 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 or decky: A person whose job involves aiding the deck supervisor in (un)mooring, anchoring, maintenance, and general evolutions on deck.
Deck supervisor: The person in charge of all evolutions and maintenance on deck; sometimes split into two groups: forward deck supervisor, aft deck supervisor.
Deckhead: The under-side of the deck above. The inside of the boat is normally paneled over to hide the structure, pipes, electrical wires. It can be in thin wood planks, often covered with a vinyl lining, or in thin PVC or now even in fiberglass planks.
Decks awash: A situation in which the deck of the vessel is partially or wholly submerged, possibly as a result of excessive listing or a loss of buoyancy.
Decommission: To formally take (a naval vessel) out of active service, after which the vessel is said to be out of commission or decommissioned. Sometimes used less formally to mean taking a commercial ship out of service.
Depot ship: A ship which acts as a mobile or fixed base for other ships and submarines or supports a naval base.
Depth of hold: The height from the lowest part of the hull inside the ship, at its midpoint, to the ceiling that is made up of the uppermost full length deck. For old warships it is to the ceiling that is made up of the lowermost full length deck.
Derrick: A lifting device composed of one mast or pole and a boom or jib which is hinged freely at the bottom.
Despatch boat: Alternative spelling of dispatch boat.
Destroyer (originally torpedo boat destroyer): A type of fast and maneuverable small warship introduced in the 1890s to protect capital ships from torpedo boat attack, since increased in size and capabilities to become a long-endurance warship intended to escort larger vessels in a fleet, convoy, or battle group and defend them against submarines, surface ships, aircraft, and missiles.
Destroyer escort: The United States Navy term for a smaller, lightly armed warship built in large numbers during World War II (and ins smaller numbers thereafter), cheaper, slower, and less-well-armed than a destroyer but larger and more heavily armed than a corvette and designed to escort convoys of merchant ships or naval auxiliaries or second-line naval forces. Employed primarily for anti-submarine warfare, but also provided some protection against aircraft and smaller surface ships. Generally known as "frigates" in other navies, and designated as such in the U.S. Navy as well by the 1970s.
Destroyer leader: A large destroyer suitable for commanding a flotilla of destroyers or other small warships; a type of flotilla leader.
Devil seam: The devil was possibly a slang term for the garboard seam, hence "between the devil and the deep blue sea" being an allusion to keel hauling, but a more popular version seems to be the seam between the waterway and the stanchions which would be difficult to get at, requiring a cranked caulking iron, and a restricted swing of the caulking mallet.
Devil to pay (or Devil to pay, and no pitch hot): "Paying" the devil is sealing the devil seam. It is a difficult and unpleasant job (with no resources) because of the shape of the seam (up against the stanchions) or if the devil refers to the garboard seam, it must be done with the ship slipped or careened.
Dhow: the generic name of a number of traditional sailing vessels with one or more masts with lateen sails used in the Red Sea and Indian Ocean region, typically weighing 300 to 500 tons, with a long, thin hull. They are trading vessels primarily used to carry heavy items, like fruit, fresh water or merchandise. Crews vary from about thirty to around twelve, depending on the size of the vessel.
Dinghy: 1. A type of small boat, often carried or towed as a ship’s boat by a larger vessel.; 2. Also a small racing yacht or recreational open sailing boat, often used for beginner training rather than sailing full-sized yachts.; 3. Utility dinghies are usually rowboats or have an outboard motor, but some are rigged for sailing.
Directional light: A light illuminating a sector or very narrow angle and intended to mark a direction to be followed.
Dispatch boat: A vessel ranging in size from a small boat to a large ship tasked to carry military dispatches from ship to ship, from ship to shore, or, occasionally, from shore to shore.
Displacement: The weight of water displaced by the immersed volume of a ship's hull, exactly equivalent to the weight of the whole ship.
Displacement hull: A hull designed to travel through the water, rather than planing over it.
Disrate: To reduce in rank or rating; demote.
Distinguishing mark: A flag flown to distinguish ships of one seagoing service of a given country from ships of the country‍ 's other seagoing service(s) when ships of more than one of the country‍ 's seagoing services fly the same ensign.
Dock: 1. In American usage, a fixed structure attached to shore to which a vessel is secured when in port, generally synonymous with pier and wharf, except that pier tends to refer to structures used for tying up commercial ships and to structures extending from shore for use in fishing, while dock refers more generally to facilities used for tying up ships or boats, including recreational craft.; 2. In British usage, the body of water between two piers or wharves which accommodates vessels tied up at the piers or wharves.; 3. To tie up along a pier or wharf.
Dockyard: A facility where ships or boats are built and repaired. Routinely used as a synonym for shipyard, although dockyard sometimes is associated more closely with a facility used for maintenance and basing activities, while shipyard sometimes is associated more closely with a facility used in construction.
Dodger: A hood forward of a hatch or cockpit to protect the crew from wind and spray. Can be soft or hard.
Dog watch: A short watch period, generally half the usual time (e.g. a two-hour watch rather than a four-hour one). Such watches might be included in order to rotate the system over different days for fairness, or to allow both watches to eat their meals at approximately normal times.
Doghouse: A slang term (in the US, mostly) for a raised portion of a ship's deck. A doghouse is usually added to improve headroom below or to shelter a hatch.
Dogvane: A small weather vane, sometimes improvised with a scrap of cloth, yarn or other light material mounted within sight of the helmsman. (See tell-tale)
Doldrums or equatorial calms: The equatorial trough, with special reference to the light and variable nature of the winds.^[17]
Dolphin: A structure consisting of a number of piles driven into the seabed or riverbed as a marker.
Dory or doree, dori, or (RN) dorey: A shallow-draft, lightweight boat, about 5 to 7 metres long, with high sides, a flat bottom and sharp bows. Traditionally used as fishing boats, both in coastal waters and in the open sea.
Double-shotted: The practice of loading smooth-bore cannon with two cannon-balls.
Downbound: 1. A vessel traveling downstream.; 2. Eastward-traveling vessels in the Great Lakes region (terminology as used by the St. Lawrence Seaway Development Corporation).
Downhaul: A line used to control either a mobile spar, or the shape of a sail. A downhaul can also be used to retrieve a sail back on deck.
Drabbler: An extra strip of canvas secured below a bonnet (q.v.), further to increase the area of a course
Draft or draught (both /ˈdrɑːft/): The depth of a ship's keel below the waterline.
Dragon boat (also dragonboat): One of a family of traditional paddled long boats of various designs and sizes found throughout Asia, Africa and the Pacific Islands. For competitive events, they are generally rigged with decorative Chinese dragon heads and tails. Dragon boat races are traditionally held during the annual summer solstice festival.
Dreadnought: A type of battleship designed with an "all-big-gun" armament layout in which the ship‍ 's primary gun power resided in a primary battery of its largest guns intended for use at long range, with other gun armament limited to small weapons intended for close-range defense against torpedo boats and other small warships. Most, but not all, dreadnoughts also had steam turbine propulsion. Predominant from 1906, dreadnoughts differed from earlier steam battleships, retroactively dubbed "predreadnoughts", which had only a few large guns, relied on an intermediate secondary battery used at shorter ranges for most of their offensive power, and had triple-expansion steam engines.
Dress overall: To string International Code of Signals flags, arranged at random, from masthead to masthead (if the vessel has more than one mast) and then down to the taffrail, on a ship in harbor as a sign of celebration of a national, local, or personal anniversary, event, holiday, or occasion. When a ship is properly dressed overall, ensigns fly at each masthead unless displaced by another flag – for example, that of a flag officer on board – in addition to the ensign flown in the usual position at the stern.
Dressing down: 1. Treating old sails with oil or wax to renew them.; 2. A verbal reprimand.
Drifter: A type of fishing boat designed to catch herring in a long drift net, long used in the Netherlands and Great Britain.
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 /ˈdroʊɡ/: A device to slow a boat down in a storm so that it does not speed excessively down the slope of a wave and crash into the next one. It is generally constructed of heavy flexible material in the shape of a cone. Also see sea anchor.
Drydock: A narrow basin or vessel used for the construction, maintenance, and repair of ships, boats, and other watercraft 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.
Dunnage /ˈdʌnɨdʒ/: 1. Loose packing material used to protect a ship's cargo from damage during transport. (See also fardage); 2. Personal baggage.
Dunsel: A part on a ship that has no use.

E

Earings: Small lines, by which the uppermost corners of the largest sails are secured to the yardarms.
East Indiaman: Any ship operating under charter or license to the East India Company (England), or to the Danish East India Company, French East India Company, Dutch East India Company, Portuguese East India Company, or Swedish East India Company from the 17th to the 19th centuries.
Echo sounding: Measuring the depth of the water using a sonar device. Also see sounding and swinging the lead.
Embayed: The condition where a sailing vessel (especially one which sails poorly to windward) is confined between two capes or headlands by a wind blowing directly onshore.
En echelon: An arrangement of gun turrets whereby the turret on one side of the ship is placed further aft than the one on the other side, so that both turrets can fire to either side.
Diagram showing the Minas Geraes-class battleship with its central guns arranged en echelon.
Engine order telegraph: A communications device used by the pilot to order engineers in the engine room to power the vessel at a certain desired speed. Also Chadburn.
Engine room: One of the machinery spaces of a vessel, usually the largest one, containing the ship‍ 's prime mover (usually a diesel or steam engine or a gas or steam turbine). Larger vessels may have more than one engine room.
Ensign: 1. Ensign, the principal flag or banner flown by a ship to indicate her nationality.; 2. Ensign, the lowest grade of commissioned officer in the United States Navy.
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.
Eye splice: A closed loop or eye at the end a line, rope, cable, etc. It is made by unraveling its end and joining it to itself by intertwining it into the lay of the line. Eye splices are very strong and compact and are employed in moorings and docking lines among other uses.

F

Fair: 1. A smooth curve, usually referring to a line of the hull which has no deviations.; 2. To make something flush.; 3. A line is fair when it has a clear run.; 4. A wind or current is fair when it offers an advantage to a boat.
Fair winds and following seas: A blessing wishing the recipient a safe journey and good fortune.
Fairlead: A ring, hook or other device used to keep a line or chain running in the correct direction or to prevent it rubbing or fouling.
Fairwater: A structure that improves the streamlining of a vessel.
Falkuša: A traditional fishing boat with a lateen sail on a single mast used by fishermen from the town of Komiža on the Adriatic island of Vis.
Fall: The part of the tackle that is hauled upon.
Fall off: To change the direction of sail so as to point in a direction that is more down wind. To bring the bow leeward. Also bear away, bear off or head down. This is the opposite of pointing up or heading up.
Fantail: Aft end of the ship, also known as the Poop deck.
Fardage: Wood placed in bottom of ship to keep cargo dry. (See also dunnage)
Fast: Fastened or held firmly (fast aground: stuck on the seabed; made fast: tied securely).
Fathom /ˈfæðəm/: A unit of length equal to 6 feet (1.8 m), roughly measured as the distance between a man's outstretched hands. Particularly used to measure depth.
Fathometer: A depth finder that uses sound waves to determine the depth of water.
Felucca: A traditional wooden sailing boat with a rig consisting of one or two lateen sails, used in protected waters of the Red Sea and eastern Mediterranean and particularly along the Nile in Egypt and Sudan, and also in Iraq.
Fend Off: A command given to the crew to stop what they are now doing and to immediately manually prevent the boat from banging into the docks or other boats.
Fender: An air or foam filled bumper used in boating to keep boats from banging into docks or each other.
Fetch: 1. The distance across water which a wind or waves have traveled.; 2. To reach a mark without tacking.
Fid: 1. A tapered wooden tool used for separating the strands of rope for splicing.; 2. A bar used to fix an upper mast in place.
Fife rail: A freestanding pinrail surrounding the base of a mast and used for securing that mast's sails' halyards with a series of belaying pins.
Fifie: A sailing boat with two masts with a standard rig consisting of a main dipping lugsail and a mizzen standing lug sail developed in Scotland; used for commercial fishing from the 1850s until the 20th century.
Fighting top: An enlarged top designed to allow gunfire downward onto an enemy ship. A fighting top could have small guns installed in it or could serve as a platform for snipers armed with muskets or rifles.
Figurehead: A symbolic image at the head of a traditional sailing ship or early steamer.
Fin: A term used in European and British Commonwealth countries for a tower-like structure on the dorsal (topside) surface of a submarine; called a sail in the United States.
Fine: Narrow (fine) in appearance from the vantage point of a lookout or other person viewing activity in the vicinity of a ship, e.g., another ship off the starboard bow with her bow or stern facing the viewer's ship could be described as "fine on the starboard bow" of the viewer's ship.
Fire ship: 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.
Fireroom: The compartment in which the ship's boilers or furnaces are stoked and fired.
First-rate: The classification for the largest sailing warships of the 17th through 19th centuries. They had 3 masts, 850+ crew and 100+ guns.
First lieutenant: 1. In the Royal Navy, the senior lieutenant on board; responsible to the commanding officer for the domestic affairs of the ship's company. Also known as 'Jimmy the One' or 'Number One'. Removes his cap when visiting the mess decks as token of respect for the privacy of the crew in those quarters. Officer in charge of cables on the forecastle.; 2. In the United States Navy, the officer on a ship serving as the senior person in charge of all deck hands.
First mate: The second-in-command of a commercial ship.
Fish: 1. To repair a mast or spar with a fillet of wood.; 2. To secure an anchor on the side of the ship for sea (otherwise known as "catting".); 3. A slang term for a self-propelled torpedo.
Fitting-out: The period after a ship is launched during which all the remaining construction of the ship is completed and she is readied for sea trials and delivery to her owners.
Fixed propeller: A propeller mounted on a rigid shaft protruding from the hull of a vessel, usually driven by an inboard motor; steering must be done using a rudder. See also outboard motor and sterndrive.
Flag hoist: A number of signal flags strung together to convey a message, e.g., 'England expects...'
Flag of convenience: The business practice of registering a merchant ship in a sovereign state different from that of the ship‍ 's owners, and flying that state‍ 's civil ensign on the ship. The practice allows the ship‍ 's owner to reduce operating costs or avoid the regulations of the owner‍ 's country.
Flag officer: 1. A commissioned officer senior enough to be entitled to fly a flag to mark the ship or installation from which he or she exercises command, in English-speaking countries usually referring to the senior officers of a navy, specifically those who hold any of the admiral ranks and in some cases to those holding the rank of commodore. In modern American usage, additionally applied to U.S. Coast Guard and National Oceanic and Atmospheric Administration Commissioned Corps officers and general officers in the U.S. Army, U.S. Air Force, and U.S. Marine Corps entitled to fly their own flags.; 2. A formal rank in the mid-19th-century United States Navy, conveyed temporarily upon senior captains in command of squadrons of ships, soon rendered obsolete by the creation of the ranks of commodore and rear admiral.
Flagship: 1. A vessel used by the commanding officer of a group of naval ships (reflecting the custom of its commander, characteristically a flag officer, flying a distinguishing flag aboard the ship on which he or she is embarked.; 2. Used more loosely, the lead ship in a fleet of naval or commercial vessels, typically the first, largest, fastest, most heavily armed, or, in terms of media coverage, best-known.
Flank: The maximum speed of a ship. Faster than "full speed".
Flare: 1. A curvature of the topsides outward towards the gunwale.; 2. A pyrotechnic signalling device, usually used to indicate distress.
Flatback: A Great Lakes slang term for a vessel without any self-unloading equipment.
Flattop: Slang term for an aircraft carrier (q.v.).
Flemish: To coil a line that is not in use so that it lies flat on the deck.
Flight deck: A flat deck used for the launch and recovery of aircraft.
Flotilla leader: A warship suitable for commanding a flotilla of destroyers or other small warships, typically a small cruiser or a large destroyer, in the latter case known as a destroyer leader.
Flotsam: Debris or cargo that remains afloat after a shipwreck. See also jetsam.
Fluke: The wedge-shaped part of an anchor's arms that digs into the bottom.
Flush deck: An upper deck of a vessel that extends unbroken from stem to stern.
Flush decker: 1. A United States Navy destroyer of the World War I-era Caldwell, Wickes, or Clemson class, produced in very large numbers.; 2. Any ship with a flush deck.
Fluyt (also fluit or flute): A Dutch transoceanic sailing cargo vessel, square-rigged with two or three masts that were much taller than the masts of a galleon, developed in the 16th century and widely used in the 17th and 18th centuries.
Fly by night: A large sail used only for sailing downwind, requiring little attention.
Folding propeller: A propeller with folding blades, furling to reduce drag on a sailing vessel when not in use.
Following sea: Wave or tidal movement going in the same direction as a ship
Foo-foo band: An impromptu musical band on late 19th-century sailing vessels, made up from members of the ship's crew^[18]^[19]
Foot: 1. The lower edge of any sail.; 2. The bottom of a mast.; 3. A measurement of 12 inches.
Footloose: If the foot of a sail is not secured properly, it is footloose, blowing around in the wind.
Footrope: Each yard on a square rigged sailing ship is equipped with a footrope for sailors to stand on while setting or stowing the sails
Force: See Beaufort scale.
Fore, forward (/ˈfɒrərd/, and often written "for'ard"): Towards the bow (of the vessel).
Fore-and-aft rig: A sailing rig consisting mainly of sails that are set along the line of the keel rather than perpendicular to it. Such sails are referred to as "fore-and-aft rigged."
Forecastle: A partial deck, above the upper deck and at the head of the vessel; traditionally the sailors' living quarters. Pronounced /ˈfoʊksəl/. The name is derived from the castle fitted to bear archers in time of war.
Forefoot: The lower part of the stem of a ship.
Foremast jack: An enlisted sailor, one who is housed before the foremast.
Forepeak: The part of the hold of a ship within the angle of the bow.
Forestays: Long lines or cables, reaching from the bow of the vessel to the mast heads, used to support the mast.
Foul: 1. Having freedom of motion interfered with by collision or entanglement; entangled; the opposite of clear. For instance, a rope is foul when it does not run straight or smoothly, and an anchor is foul when it is caught on an obstruction.; 2. A breach of racing rules.; 3. An area of water treacherous to navigation due to many shallow obstructions such as reefs, sandbars, or many rocks, etc.; 4. Foul the range: To block another vessel from firing her guns at a target.
Foulies: A slang term for oilskins, the foul-weather clothing worn by sailors. See also oilskins.
Founder: To fill with water and sink → Founder (Wiktionary)
Fourth rate: In the British Royal Navy, a fourth rate was, during the first half of the 18th century, a ship of the line mounting from 46 up to 60 guns.
Frame: 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.
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.
Freighter: A cargo ship.
Frigate: 1. In the 17th century, any warship built for speed and maneuverability.; 2. In the 18th and early 19th centuries, a sailing warship with a single continuous gun deck, typically used for patrolling, blockading, etc., but not in line of battle.; 3. In the second half of the 19th century, a type of warship combining sail and steam propulsion, typically of ironclad timber construction, with all guns on one deck.; 4. In the 20th and 21st centuries, a warship, smaller than a destroyer, originally introduced during World War II as an anti-submarine vessel but now general-purpose.; 5. In the United States Navy from the 1950s until the 1970s, a type of guided-missile antiaircraft ship built on a destroyer-sized hull, all reclassified as "guided-missile cruisers" in 1975.
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-rigged 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".
Funnel (also stack): The smokestack of a ship, used to expel boiler steam and smoke or engine exhaust.
Furl: To roll or gather a sail against its mast or spar.
Fusta (also fuste, foist, or galliot): A narrow, light, and fast ship with shallow draft, powered by both oars and sail, with a single mast carrying a lateen sail; a favorite of North African corsairs during the 16th and 17th centuries.
Futtocks: Pieces of timber that make up a large transverse frame.

G

Gaff: 1. Gaff rig: The spar that holds the upper edge of a four-sided fore-and-aft mounted sail.; 2. Fishing gaff: A hook on a long pole to haul fish in.
Gaff rigged: A boat rigged with a four-sided fore-and-aft sail with its upper edge supported by a spar or gaff which extends aft from the mast.
Gaff vang: A line rigged to the end of a gaff and used to adjust a gaff sail's trim.
Galleass: 1. An oared warship of the 1500s equipped with a gundeck, larger and equipped with more sails than a galley.; 2. A flat-bottom commercial sailing vessel of the North Sea and western Baltic Sea.
Galleon: A large, multi-decked sailing ship used primarily by European states from the 16th to 18th centuries.
Galley: 1. Galley, the kitchen of a ship.; 2. Galley, a type of ship propelled by oars used especially in the Mediterranean for warfare, piracy, and trade from the 700s BC to the 1500s AD, with some in use until the early 1800s.; 3. A type of oared gunboat built by the United States in the late 18th century, akin to a brigantine but termed "galley" for administrative and funding purposes.
Galliot: See fusta.
Gam: A meeting of two (or more) whaling ships at sea. The ships each send out a boat to the other, and the two captains meet on one ship, while the two chief mates meet on the other.^[20]
Gammon iron: The bow fitting which clamps the bowsprit to the stem.
Gangplank: A movable bridge used in boarding or leaving a ship at a pier; also known as a "brow".
Gangway: An opening in the bulwark of the ship to allow passengers to board or leave the ship.
Garbling: The (illegal) practice of mixing cargo with garbage.
Garboard: The strake closest to the keel (from Dutch gaarboard).
Garboard planks: The planks immediately either side of the keel.
Gash: Any refuse or rubbish which is discarded into a refuse container or dustbin which is known as "gash fanny" (South African Navy).
Gash Fanny: Refuse container or dustbin.
Gennaker: A large, lightweight sail used for sailing a fore-and-aft rig down or across the wind, intermediate between a genoa and a spinnaker.
Genoa or genny (both /ˈdʒɛni/): A large jib, strongly overlapping the mainmast.
Ghost: To sail slowly when there is apparently no wind.
Gibe: See gybe.
Gig (Captain‍ 's gig): A boat on naval ships at the disposal of the ship‍ 's captain for his or her use in transportation to other ships or to the shore.
Gin-pole: A pole that is attached perpendicular to the mast, to be used as a lever for raising the mast. Also jin-pole.
Give-way (vessel): Where two vessels are approaching one another so as to involve a risk of collision, this is the vessel which is directed to keep out of the way of the other.
Glass: A marine barometer. (Older barometers used mercury-filled glass tubes to measure and indicate barometric pressure.)
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.
Go-fast boat: is a small, fast boat designed with a long narrow platform and a planing hull to enable it to reach high speeds – also called ‘a rum-runner’, or, more recently, ‘a cigarette boat’.
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. See also running.
Grapeshot: Small balls of lead fired from a cannon, analogous to shotgun shot but on a larger scale. Similar to canister shot but with larger individual shot. Used to injure personnel and damage rigging more than to cause structural damage.
Grave: To clean a ship’s bottom.
Graving dock: A narrow basin, usually made of earthen berms and concrete, closed by gates or by a caisson, into which a vessel may be floated and the water pumped out, leaving the vessel supported on blocks; the classic form of drydock.
Green-to-green: A passage of two vessels moving in the opposite direction on their starboard sides, so called because the green navigation light on one of the vessels faces the green light on the other vessel.
Gripe: Temporary eye in a line(rope).
Grog: Watered-down pusser's rum consisting of half a gill with equal part of water, issued to all seamen over twenty. (CPOs and POs were issued with neat rum) 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 favours 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 favour 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 a lot of grog.
Ground: The bed of the sea.
Grounding: When a ship (while afloat) touches the bed of the sea, or goes "aground" (q.v.).
Growler: A small iceberg or ice floe which is barely visible above the surface of the water.
Guard boat: A boat which makes the rounds of a fleet at anchor to see that due watch is kept at night.
Guard ship: 1. A warship stationed at a port or harbour to act as a guard there.; 2. In former times in the British Royal Navy, a ship which received men impressed for naval service, often the flagship of the admiral commanding along the coast.; 3. In Soviet and Russian terminology, a guard ship (storozhevoj korabl‍ ') is a small, general purpose patrol or escort vessel.
Gun deck: 1. Up through the 19th century, a deck aboard a ship that was primarily used for the mounting of cannon to be fired in broadsides.; 2. On smaller vessels (of frigate size or smaller) up through the 19th century, the completely covered level under the upper deck, even though in such smaller ships it carried none of the ship‍ 's guns.; 3. On marine seismic survey vessels, the lowest deck on the ship, which carries the seismic source arrays, consisting of air guns arranged in clusters.; 4. In naval slang, to fabricate or falsify something; in modern usage, meaning especially to falsify documentation in order to avoid doing work or make present conditions seem acceptable without having made a real effort to improve them.
Gunner's daughter: see Kissing the gunner's daughter.
Gunport: The opening in the side of the ship or in a turret through which the gun fires or protrudes.
Gunwale /ˈɡʌnəl/: Upper edge of the hull.
Gybe or jibe (both /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.)

H

Half-breadth plan: In shipbuilding, an elevation of the lines of a ship, viewed from above and divided lengthwise.
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.
Hammock: Canvas sheets, slung from the deckhead in messdecks, in which seamen slept. "Lash up and stow" a piped command to tie up hammocks and stow them (typically) in racks inboard of the ship's side to protect crew from splinters from shot and provide a ready means of preventing flooding caused by damage.
Hand: To furl a sail.
Hand bomber: A ship using coal-fired boilers shoveled in by hand.
Hand over fist: To climb steadily upwards, from the motion of a sailor climbing shrouds on a sailing ship (originally "hand over hand").
Handsomely: With a slow even motion, as when hauling on a line "handsomely".
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.
Hangar deck: An enclosed deck, usually beneath the flight deck, on an aircraft carrier intended for use as a hangar in servicing and storing aircraft.
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.
Harbor of refuge: A place where ships in transit can find shelter from a storm. These are often man-made jetty enclosed areas along a featureless coastline where no nearby natural deep water harbors exist.
Hard: A section of otherwise muddy shoreline suitable for mooring or hauling out.
Hard-a-lee: See lee-oh.
Harden up: Turn towards the wind; sail closer to the wind.
Harness cask: A large usually round tub lashed to a vessel's deck and containing dried and salted provisions for daily use.
Harness tub: See "harness cask".
Hardtack: A hard and long-lasting dry biscuit, used as food on long journeys. Also called ship's biscuit.
Hatchway, hatch: A covered opening in a ship's deck through which cargo can be loaded or access made to a lower deck; the cover to the opening is called a hatch.
Haul: 1. To steer (a vessel) closer to the direction of the wind.; 2. To shift forward, i.e., more toward the bow of the vessel.
Hauling wind: Pointing the ship towards the direction of the wind; generally not the fastest point of travel on a sailing vessel.
Hawsepipe, hawsehole or hawse /ˈhɔːz/: The shaft or hole in the side of a vessel's bow through which the anchor chain passes.
Hawsepiper: An informal term for a merchant ship’s officer who began their career as an unlicensed merchant seaman, and so did not attend a traditional maritime academy to earn their officer's licence (also see before the mast).
Hawser: Large rope used for mooring or towing a vessel.
Head: 1. The forwardmost or uppermost portion of the ship.; 2. The forwardmost or uppermost portion of any individual part of the ship, e.g., the masthead, the beakhead, the stemhead, etc.; 3. The top edge of a sail.; 4. The toilet or latrine of a vessel, which in sailing ships projected from the bows and therefore was located in the "head" of the vessel.
Head boat: A fishing boat that takes recreational fishermen out for a fee paid individually by each person (i.e., per head). A head boat differs from a charter boat, which is a fishing boat that a party of fishermen hires for an agreed-upon period.
Head of navigation: The farthest point above the mouth of a river that can be navigated by ships.
Head rail: A curved rail that extends from the figurehead to the bow of a ship.
Head sea: A sea where waves are directly opposing the motion of the ship.
Header: A change in the wind direction which forces the helmsman of a close hauled sailboat to steer away from its current course to a less favorable one. This is the opposite of a lift.
Headsail: Any sail flown in front of the most forward mast.
Heave: A vessel's transient, vertical, up-and-down motion.
Heave down: Turn a ship on its side (for cleaning). Also known as Careening
Heaving to: Or Hove to. Stopping 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.
Heel: 1. The lean caused by the wind's force on the sails of a sailing vessel.; 2. The inclination or canting of a vessel to one side or the other from the vertical as she maneuvers, as The ship heeled to port as she turned to starboard.; 3. The lowest or last part of something, such as the heel of the mast or the heel of the vessel.
Helm: A ship's steering mechanism; see tiller and ship's wheel. The wheel and/or wheelhouse area. See also wheelhouse.
Helmsman: A person who steers a ship.
Herring buss: A type of seagoing fishing vessel used by Dutch and Flemish herring fishermen from the 15th through the early 19th century.
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 fully out.
Hitch: A knot used to tie a rope or line to a fixed object. Also see bend.
Hog: 1. A fore-and-aft structural member of the hull fitted over the keel to provide a fixing for the garboard planks.; 2. A rough flat scrubbing brush for cleaning a ship’s bottom under water.
Hogging: When the peak of a wave is amidships, causing the hull to bend so the ends of the keel are lower than the middle. The opposite of sagging. Also refers to a permanent distortion of the hull in the same manner caused, over time, by the bow and stern of a ship being less buoyant than the midships section. During the Age of Sail, shipwrights employed a number of different designs of braces to stiffen ships' hulls against this warping.
Hoist: The height of a fore-and-aft sail as measured next to the mast or stay.
Hold: In earlier use, below the orlop deck, the lower part of the interior of a ship's hull, especially when considered as storage space, as for cargo. In later merchant vessels it extended up through the decks to the underside of the weather deck.
Holiday: A gap in the coverage of newly applied paint, slush, tar or other preservative.
Holystone: A chunk of sandstone used to scrub the decks. The name comes from both the kneeling position sailors adopt to scrub the deck (reminiscent of genuflection for prayer), and the stone itself (which resembled a Bible in shape and size).
Home port: The port at which a vessel is based. Often confused with the ship‍ 's port of registry, which is the port listed in the vessel‍ 's registration documents and lettered on her stern and which may differ from her home port. In the cruise ship industry, the term "home port" often is mistakenly used to refer to a ship‍ 's port of departure.
Horn: A sound signal which uses electricity or compressed air to vibrate a disc diaphragm.
Horn timber: A fore-and-aft structural member of the hull sloping up and backwards from the keel to support the counter.
Horse: 1. Attachment of sheets to deck of vessel (main-sheet horse).; 2. (v.) To move or adjust sail by brute hand force rather than using running rigging.
Hotel load: The base amount of electricity needed to work the ship.
Hounds: Attachments of stays to masts.
Hulk: 1. A ship, often an old ship or one that has become obsolete or uneconomical to operate, that has had its rigging or internal equipment removed and is incapable of going to sea, but that is afloat and continues to serve a useful function, such as providing living, office, training, storage, or prison space.; 2. To convert a ship into such a hulk.; 3. Less commonly, a ship that has been launched but not completed.; 4. Also less commonly, an abandoned wreck or shell of a ship.
Hull: The shell and framework of the basic flotation-oriented part of a ship.
Hull-down: Of a vessel when only its upper parts are visible over the horizon.
Hull speed: The maximum efficient speed of a displacement-hulled vessel.
Hydrofoil: A boat with wing-like foils mounted on struts below the hull, lifting the hull entirely out of the water at speed and allowing water resistance to be greatly reduced.

I

Icebreaker: A special-purpose ship or boat designed to move and navigate through ice-covered waters.
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
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.
In irons: When the bow of a sailboat is headed into the wind and the boat has stalled and is unable to maneuver.
In ordinary: An 18th- and 19th-century term originally used to refer to a naval vessel out of service for repair or maintenance, later coming to mean naval ships in reserve with no more than a caretaker crew.
In-water Survey: A method of surveying the underwater parts of a ship while it is still afloat instead of having to drydock it for examination of these areas as was conventionally done.
In way of: In the vicinity of; in the area of.
Inboard: 1. Situated within a vessel.; 2. Situated within a vessel and positioned close (or closer than another item, when contrasted with that item) to her centerline (q.v.).; 3. Situated outside a vessel but nearer to her hull, e.g., The larger boat was tied up alongside the ship inboard of the smaller boat.; 4. Nearer the pier or shore, e.g., The tanker and cargo ship were tied up at the pier alongside one another with the tanker inboard of the cargo ship.
Inboard motor: An engine mounted within the hull of a vessel, usually driving a fixed propeller by a shaft protruding through the stern. Generally used on larger vessels. See also sterndrive and outboard motor.
Inboard-Outboard drive system: See sterndrive.
Inglefield clip: A type of clip for attaching a flag to a flag halyard.
Inshore: 1. Near (especially in sight of) or toward the shore.; 2. Of a wind, blowing from the sea to the land.
Iron topsail: An auxiliary motor on a schooner.
Iron wind: What sailors call inboard engines.
Ironclad: A steam-propelled warship protected by iron or steel armor plates of the period from 1859 until the 1890s (when the term "ironclad" fell out of use).
Island: The superstructure of an aircraft carrier that extends above the flight deck. A carrier that lacks one is said to be flush-decked.

J

Jack: 1. A sailor. Also jack tar or just tar.; 2. A flag. 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.
Jack Dusty: A naval stores clerk.
Jack Tar: A sailor dressed in 'square rig' with square collar. Formerly with a tarred pigtail.
Jacklines or jack stays: Lines, often steel wire with a plastic jacket, from the bow to the stern on both port and starboard. A crewmember clips his safety harness to a jackline, allowing him to walk along the deck while still being safely attached to the vessel.
Jenny: See genoa
Jetty: A man-made wall in open water rising several feet above high tide made of rubble and rocks used to create a breakwater, shelter, erosion control, a channel, or other such purpose.
Jetsam: Debris ejected from a ship that sinks or washes ashore. See also Flotsam.
Jib: A triangular staysail at the front of a ship.
Jibboom: A spar used to extend the bowsprit.
Jibe: See gybe.
Jibe-ho: See gybe-oh.
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.
Jollies: Traditional Royal Navy nickname for the Royal Marines.
Joggle: a slender triangular recess cut into the faying surface of a frame or steamed timber to fit over the land of clinker planking, or cut into the faying edge of a plank or rebate to avoid feather ends on a strake of planking. The feather end is cut off to produce a nib. The joggle and nib in this case is made wide enough to allow a caulking iron to enter the seam.
Jonah: A person (either a sailor or a passenger) who carries a jinx, one whose presence on board brings bad luck and endangers the ship.
Junk: 1. Old cordage past its useful service life as lines aboard ship. The strands of old junk were teased apart in the process called picking oakum.; 2. A sailing ship of classic Chinese design with characteristic full batten sails that span the masts usually on unstayed rigs.
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.

K

Kedge: A technique for moving or turning a ship by using a relatively light anchor known as a kedge. The kedge anchor may be dropped while in motion to create a pivot and thus perform a sharp turn. The kedge anchor may also be carried away from the ship in a smaller boat, dropped, and then weighed, pulling the ship forward.
Keel: The central structural basis of the hull.
Keelhauling: Maritime punishment: to punish by dragging under the keel of a ship.
Kellet: See anchor sentinel.
Kelson: The timber immediately above the keel of a wooden ship.
Kentledge: Weights (often scrap or pig iron) used as permanent high-density ballast.
Ketch: A two-masted fore-and-aft rigged sailboat with the aft mast (the mizzen) mounted (stepped) afore (in front of) the rudder.
Killick: A small anchor. A fouled killick is the substantive badge of non-commissioned officers in the RN. 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.
Kicking strap: A rope, tackle or hydraulic ram running from the mast at or just above deck level to a point part-way along the boom of a yacht's mainsail or mizzen. Its function is to pull the boom down, flattening the sail in strong winds, reducing twist and preventing the boom from kicking up when running.
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.
Kingston valve: A valve, which can be opened from the inside of the ship, that connects the sea to internal fuel, water, or ballast tanks (see also seacock).
Kissing the gunner's daughter: Bending over the barrel of a gun for punitive beating with a cane or cat.
Kitchen rudder: Hinged cowling around a fixed propeller, allowing the drive to be directed to the side or forwards to manoeuvre the vessel.
Knee: 1. Connects two parts roughly at right angles, e.g. deck beams to frames.; 2. A vertical rubber fender used on pushboats or piers, sometimes shaped like a human leg bent slightly at the knee
Knighthead: 1. A mitred backing timber which extends the after line of the rabbet in the stem to give extra support to the ends of the planks and the bowsprit.; 2. A bollard or bitt.; 3. Either of two timbers rising from the keel of a sailing ship and supporting the inner end of the bowsprit.
Knock: See Header.
Knockdown: The condition of a sailboat being pushed abruptly to horizontal, with the mast parallel to the water surface.
Knot: A unit of speed: 1 nautical mile (1.8520 km; 1.1508 mi) 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. Sometimes "knots" is mistakenly stated as "knots per hour," but the latter is a measure of acceleration (i.e., "nautical miles per hour per hour") rather than of speed.
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.
Lagan: Debris that has sunk to the seabed.
Laid up: To be placed in reserve or mothballed. The latter usage is used in modern times and can refer to a specific set of procedures used by the US Navy to preserve ships in good condition.
Laker: Great Lakes slang for a vessel who spends all its time on the 5 Great Lakes.
Land lubber: A person unfamiliar with being on the sea.
Lanyard: A rope that ties something off.
Larboard: Obsolete term for the left side of a ship. Derived from "lay-board" providing access between a ship and a quay, when ships normally docked with the left side to the wharf. Replaced by port side or port, to avoid confusion with starboard.
Large: See By and large.
Lateen sail or Latin-rig: A fore-and-aft triangular sail set on a long yard mounted at an angle to the mast.
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).
Launch: 1. Traditionally, a launch was the largest ship‍ 's boat carried by a warship.; 2. In modern usage, a large motorboat.; 3. To dispatch a ship down a slipway, prior to fitting-out and commissioning.
Lay: To come and go, used in giving orders to the crew, such as "lay forward" or "lay aloft". To direct the course of vessel. Also, to twist the strands of a rope together. To make it to a mark, buoy, or harbor, such as "We will lay the mark".
Lay day: An unexpected delay time during a voyage often spent at anchor or in a harbor. It is usually caused by bad weather, equipment failure or needed maintenance.
Laying down: Laying the keel of a ship in a shipyard to begin her construction.
Lazaret (also Lazarette or Lazaretto): 1. A small stowage locker at the aft end of a boat.; 2. A ship or building used for quarantine of sick patients.; 3. An area on some merchant ships where provisions are stored.; 4. In modern shipbuilding and on powerboats of all sizes, the location of the steering gear equipment for the vessel.
Lazy jacks, lazyjacks: A network of cordage rigged to a point on the mast and to a series of points on either side of the boom that cradles and guides the sail onto the boom when the sail is lowered.
Lead: 1. A plummet or mass of lead attached to a line, used in sounding depth at sea.; 2. In former usage, to estimate velocity in knots.
Leadline (also sounding line): An instrument used in navigation to measure water depth; the line attached to a lead.
Leadsman: A sailor who takes soundings with a lead, measuring the depth of water.
League: A unit of length, normally equal to three nautical miles.
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.
Leeboard: A fin mounted on the side of a boat (usually in pairs) that can be lowered on the lee side of the ship to reduce leeway (similarly to a centerboard, which see).
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, mainsheet and, if rigged with one, the gaff vang.
Lee-oh or hard-a-lee: The command given to come about (tack through the wind) on a sailing boat.
Leeward (/ˈluːərd/ in nautical use): In the direction that the wind is blowing towards.
Leeway: The amount that a ship is blown leeward by the wind. See also weatherly.
Leg: In navigation, a segment of a voyage between two waypoints.
Length between perpendiculars, also p/p, p.p., pp, LPP, LBP or Length BPP: The length of a vessel along the waterline from the forward surface of the stem, or main bow perpendicular member, to the after surface of the sternpost, or main stern perpendicular member. Believed to give a reasonable idea of the vessel‍ 's carrying capacity, as it excludes the small, often unusable volume contained in her overhanging ends.
Length overall, or LOA: The maximum length of a vessel‍ 's hull measured parallel to the waterline, usually measured on the hull alone, and including overhanging ends that extend beyond the main bow and main stern perpendicular members. For sailing vessels, this may exclude the bowsprit and other fittings added to the hull, but sometimes bowsprits are included.
Let go and haul: An order indicating that the ship is now on the desired course relative to the wind and that the sails should be trimmed ('hauled') to suit.
Letter of marque and reprisal or just Letter of marque: A warrant granted to a privateer condoning specific acts of piracy against a target as a redress for grievances.
Liberty: A relatively short period when a sailor is allowed ashore for recreation. See also shore leave.
Lie to: To have the ship‍ 's sails arranged so as to counteract each other. A ship in this condition or in the process of achieving this condition is lying to.
Lifebelt, lifebuoy, lifejacket, life preserver, personal flotation device: A device such as a buoyant ring or inflatable jacket which keeps a person afloat in the water.
Lifeboat: 1. Shipboard lifeboat, kept on board a vessel and used to take crew and passengers to safety in the event of the ship being abandoned.; 2. Rescue lifeboat, usually launched from shore, used to rescue people from the water or from vessels in difficulty.
Liferaft: An inflatable, covered raft, used in the event of a vessel being abandoned.
Lift: An enabling wind shift that allows a close hauled sailboat to point up from its current course to a more favorable one. This is the opposite of a header.
Lighter: A flat-bottomed barge used to transfer goods and passengers to and from moored ships, traditionally unpowered and moved and steered using "sweeps" (long oars), with their motive power provided by water currents.
Lightvessel or lightship: A permanently anchored vessel performing the functions of a lighthouse, typically in a location where construction of the latter is impractical. These have largely been replaced by buoys or, as construction techniques have improved, actual lighthouses.
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, that specifies its use.
Line astern: In naval warfare, a line of battle formed behind a flagship
Liner: 1. During the Age of Sail, a ship-of-the-line, a major warship capable of taking its place in the main battleline of fighting ships.; 2. Any cargo or passenger ship running scheduled service along a specific route with published ports of call, excluding ferries and other vessels engaged in short-sea trading. When referring to cargo ships, liner in this sense contrasts with tramp, which refers to a ship engaged in spot-market trade that does not follow a regular schedule or make regular calls at specific ports. When referring to passenger ships, liner in this sense refers to ships providing scheduled transportation between regular ports of call and excludes cruise ships, which voyage merely for recreational purposes and not primarily as a form of transportation between ports.; 3. Ocean liner: Any large and prestigious passenger ship, including cruise ships.
List: A vessel's angle of lean or tilt to one side, in the direction called roll. Typically refers to a lean caused by flooding or improperly loaded or shifted cargo (as opposed to 'heeling', which see).
Loaded to the gunwales: Literally, having cargo loaded as high as the ship's rail; also means extremely drunk.
Lofting: The technique used to convert a scaled drawing to full size used in boat construction.
Loggerhead: An iron ball attached to a long handle, used for driving caulking into seams and (occasionally) in a fight. Hence: 'at loggerheads'.
Long stay: The relative slackness of an anchor chain; this term means taught and extended.
Longboat: 1. In the Age of Sail, a double-banked open boat carried by a sailing ship, rowed by eight or ten oarsmen, two per thwart, although designed also to be rigged for sailing; more seaworthy than a cutter or dinghy and with a beam greater than that of a gig. Eventually supplanted by the whaleboat.; 2. The largest, and thus the most capable, of boats carried on a ship.
Longship: A type of ship invented and used by the Vikings for trade, commerce, exploration, and warfare, evolving over several centuries and appearing in its complete form between the 9th and 13th centuries.
Loose cannon: An irresponsible and reckless individual whose behavior (either intended or unintended) endangers the group he or she belongs to. A loose cannon, 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.
Loose footed: A mainsail that is not connected to a boom along its foot.
Lower deck: 1. The deck of a ship immediately above the hold.; 2. In British usage, those members of a ship's company who are not officers, often used in the plural (the lower decks)
Lubber's hole: A port cut into the bottom of the mizzentop (crow's-nest) allowing easy entry and exit. It was considered "un-seamanlike" to use this easier method rather than going over the side from the shrouds, and few sailors would risk the scorn of their shipmates by doing so (at least if there were witnesses).
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.
Luff and touch her: To bring the vessel so close to wind that the sails shake.^[6]
Luff up: To steer a sailing vessel more towards the direction of the wind until the pressure is eased on the [sheet].
Luffing: 1. When a sailing vessel is steered far enough to windward that the sail is no longer completely filled with wind (the luff of a fore-and-aft sail begins to flap first).; 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(s) which results from having no wind in the sail at all.
Lying ahull: Waiting out a storm by dousing all sails and simply letting the boat drift.
Lumber hooker: A Great Lakes ship designed to carry her own deck load of lumber and to tow one or two barges. The barges were big old schooners stripped of their masts and running gear to carry large cargoes of lumber.
Lugger: A small sailing vessel with lugsails set on two or more masts and perhaps lug topsails, widely used as traditional fishing boats, particularly off the coasts of France, England and Scotland.
Lugsail: A four-sided fore-and-aft sail supported by a spar along the top that is fixed to the mast at a point some distance from the center of the spar. See Lugger.
Lying to: See Lie to.

M

Mae West: A Second World War personal flotation device used to keep people afloat in the water; named after the 1930s actress Mae West, well known for her large bosom.
Magnetic bearing: An absolute bearing (q.v.) using magnetic north.
Magnetic north: The direction towards the North Magnetic Pole. Varies slowly over time.
Main deck: The uppermost continuous deck extending from bow to stern.
Mainbrace: One of the braces 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.
Mainstay: The stay running from the top of the mainmast to the bottom of the foremast, or from the top of the foremast to the ship's steam.
Making way: When a vessel is moving under its own power.
Man-of-war or man o' war: a warship from the Age of Sail
Man overboard!: An emergency call that alerts the crew (q.v.) that someone aboard (q.v.) has gone overboard (q.v.) and must be rescued.
Man the rails: To station the crew of a naval vessel along the rails and superstructure of the vessel as a method of saluting or rendering honors.
Man the yards: To have all of the crew of a sailing vessel not required on deck to handle the ship go aloft and spread out along the yards. Originally used in harbors to display the whole crew to the harbor authorities and the other ships present to show that the vessel‍ 's guns were not manned and hence her intentions were peaceful, manning the yards has since became a display used in harbor during celebrations and other special events.
Marconi rig: Another term for Bermudan rig. The mainsail is triangular, rigged fore-and-aft with the lead edge fixed to the mast. Refers to the similarity of the tall mast to a radio aerial.
Marina: a docking facility for small ships and yachts.
Marine: 1. A soldier trained for service afloat in a (primarily) infantry force that specializes in naval campaigns and subordinated to a navy or a separate naval branch of service rather than to an army. Often capitalized (e.g., "a Marine," or "the Marines"). Notable examples are the United Kingdom's Royal Marines, formed as the Duke of York and Albany's Maritime Regiment of Foot in 1664 with many and varied duties including providing guard to ship's officers should there be mutiny aboard, and the United States Marine Corps, formed in 1775 as a separate naval service alongside the United States Navy. It is incorrect, and often viewed by marines as offensive, to refer to a marine as a "soldier" or "infantryman," as these terms refer to personnel of an army rather than those of a marine force. It also is incorrect, and sometimes considered offensive by both merchant mariners and marines, to refer to merchant mariners (q.v.) as "merchant marines," because merchant mariners are civilian sailors responsible for operating merchant ships and are not marines. Marines sometimes are thought by seamen to be rather gullible, hence the phrase "tell it to the marines," meaning that one does not believe what is being said.; 2. An alternative term for a navy, uncommon in English, but common in other languages.; 3. Of, or pertaining to, the sea (e.g, marine biology, marine insurance, marine life, marine salvage).; 4. A painting representing a subject related to the sea.
Mariner: A sailor.
Maritime: 1. Of or related to the sea (e.g., maritime activities, martime law, maritime strategy).; 2. Bordering on the sea (e.g., maritime provinces, maritime states).; 3. Living in or near the sea (e.g., maritime animals).; 4. Of or relating to a mariner or sailor.
Marlinspike: A tool used in ropework for tasks such as unlaying rope for splicing, untying knots, or forming a makeshift handle.
Mast: A vertical pole on a ship which supports sails or rigging. If a wooden, multi-part mast, this term applies specifically to the lowest portion.
Mast stepping: The process of raising the mast.
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: 1. The captain of a commercial vessel.; 2. A senior officer of a naval sailing ship in charge of routine seamanship and navigation but not in command during combat.; 3. Master, a former naval rank.
Master-at-arms: A non-commissioned officer responsible for discipline on a naval ship. Standing between the officers and the crew, commonly known in the Royal Navy as 'the Buffer'.
Matelot: A traditional Royal Navy term for an ordinary sailor.
Material: Military equipages of all descriptions for the naval services. The bombs, blankets, beans and bulletins of the Navy and Marine Corps. Taken from Nelson’s British navy as the U.S. services became professional. Related: Materiel – the military equipages of the Army and Air Force, taken from Napoleon’s French army as the U.S. services became professional.
Merchant marine: A collective term for all merchant ships registered in a given country and the civilians (especially those of that nationality) who man them; the ships and personnel in combination are said to constitute that country's merchant marine. Called the merchant navy in the United Kingdom and some other countries.
Merchant mariner: A civilian officer or sailor who serves in the merchant marine (q.v.). Sometimes such personnel are incorrectly called "merchant marines," but both merchant mariners and marines frown on this term; although merchant mariners are part of the merchant marine, they are civilians and are not in any way marines (q.v.), which are a specialized type of military personnel .
Merchant navy: A name bestowed upon the merchant marine (q.v.) of the United Kingdom by King George V, and since adopted by some other countries as well; the merchant navy's personnel are civilians, and the term "merchant navy" does not imply that they or their ships are a part of the navy. Synonymous with the term merchant marine.
Merchantman: Any non-naval passenger- or cargo-carrying vessel, including cargo ships, tankers, and passenger ships but excluding troopships.
Mess or messdeck: 1. An eating place aboard ship.; 2. A group of crew who live and eat together.
Mess deck catering: A system of catering in which a standard ration is issued to a mess supplemented by a money allowance which may be used by the mess to buy additional victuals from the pusser's stores or elsewhere. Each mess was autonomous and self-regulating. Seaman cooks, often members of the mess, prepared the meals and took them, in a tin canteen, to the galley to be cooked by the ship's cooks. As distinct from "cafeteria messing" where food is issued to the individual hand, which now the general practice.
Metacenter: The midway point between a vessel‍ 's center of buoyancy when upright and her center of buoyancy when tilted.
Metacentric height (also GM): A measurement of the initial static stability of a vessel afloat, calculated as the distance between her centre of gravity and her metacenter. A vessel with a large metacentric height rolls more quickly and therefore more uncomfortably for people on board; a vessel with a small metacentric height will roll sluggishly and may face a greater danger of capsizing.
Midships: The middle section of a vessel with reference to the longitudinal plane, as distinguished from fore or aft.
Midshipman: 1. During the 17th century, a naval rating for an experienced seaman.; 2. From the 18th century, a naval commissioned officer candidate.; 3. From the 1790s, an apprentice naval officer.; 4. From the 19th century, an officer cadet at a naval academy.; 5. In contemporary British usage, a non-commissioned officer below the rank of lieutenant. Usually regarded as being "in training" to some degree. Also known as 'Snotty'. 'The lowest form of rank in the Royal Navy' where he has authority over and responsibility for more junior ranks, yet, at the same time, relying on their experience and learning his trade from them.; 6. In contemporary American usage, a naval cadet of either sex at the United States Naval Academy. When plural (Midshipmen), the term refers to the student body of the U.S. Naval Academy (i.e., "the Brigade of Midshipmen") and is the name of its sports teams.
Midshipman's hitch: An alternative to the Blackwall hitch, preferred if the rope is greasy. Made by first forming a Blackwall hitch and then taking the underneath part and placing over the bill of the hook.^[21]
Midshipman's nuts: Broken pieces of biscuit as dessert.^[22]
Midshipman's roll: A slovenly method of rolling up a hammock transversely, and lashing it endways by one clue.^[22]
Mile: see nautical mile.
Military mast: Hollow tubular masts used in warships in the last third of the 19th century, often equipped with a fighting top armed with light-caliber guns.
Mine: A self-contained explosive device intended to damage or sink surface ships or submarines, designed to be placed in water and left to wait until they are triggered by the approach of, or contact with, a surface ship or submarines.
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.
Mizzenmast (or Mizzen): The third mast, or mast aft of the mainmast, on a ship.
Mole: A massive structure, usually of stone or concrete, used as a pier, a breakwater, or a causeway between places separated by water. May have a wooden structure built upon it and resemble a wooden pier or wharf, but a mole differs from a pier, quay, or wharf in that water cannot flow freely underneath it.
Monitor: 1. A turreted ironclad warship of the second half of the 19th century characterized by low freeboard, shallow draft, poor seaworthiness, and heavy guns, intended for riverine and coastal operations.; 2. In occasional 19th-century usage, any turreted warship.; 3. A shallow-draft armored shore bombardment vessel of the first half of the 20th century, designed to provide fire support to ground troops, often mounting heavy guns.; 4. Breastwork monitor: A 19th-century monitor designed with a breastwork to improve seaworthiness.; 5. River monitor: A monitor specifically designed for riverine operations, used during the 19th and 20th centuries and more recently than other types of monitor. River monitors generally are smaller and lighter than other monitors.
Monkey's 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.
Mould: A template of the shape of the hull in transverse section. Several moulds are used to form a temporary framework around which a hull is built.
Multipurpose vessel: A cargo ship that has fittings to carry standard shipping containers and retractable tweendecks that can be moved out of the way so that the ship can carry bulk cargo.
M.V. (or MV): Prefix for "Motor Vessel", used before a ship‍ 's name.
M.Y. (or MY): Prefix for "Motor yacht", used before a yachts name.

N

Naval infantry: 1. Sailors subordinated to a navy trained and equipped to operate ashore temporarily as an organized infantry force, but at other times responsible for the normal duties of sailors aboard ship.; 2. A specialized, permanent force of troops subordinated to a navy and responsible for infantry operations ashore. Although more specialized than sailors trained to operate temporarily as naval infantry and bearing similarities to a marine (q.n.) force or marine corps, such permanent naval infantry forces often lack the full capabilities of a marine force. Naval infantry forces also usually differ from marine forces in being subordinated directly to a navy rather than to a separate branch of naval service such as a marine corps.
Nautical mile: a unit of length corresponding approximately to one minute of arc of latitude along any meridian arc. By international agreement it is exactly 1,852 metres (approximately 6,076 feet).
Naval Programme: The British system of authorizing naval construction by an annual bill in Parliament.
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.
Nay: "no"; the opposite of "aye".
Nipper: 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 where 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".
No room to swing a cat: The entire ship's company was expected to witness floggings, assembled on deck. If it was very crowded, the bosun might not have room to swing the "cat o' nine tails" (the whip).
Non-self-sustaining: See Self-sustaining.
Nun: A type of navigational buoy often cone shaped, but if not, always triangular in silhouette, colored green in IALA region A or red in IALA region B (the Americas, Japan, Korea and the Philippines). In channel marking its use is opposite that of a "can buoy".

O

Oakum: Material used for caulking hulls. Often hemp picked from old untwisted ropes.
Ocean liner: See Liner.
Offing: the more distant part of the sea as seen from the shore and generally beyond anchoring ground.
Offshore: 1. Moving away from the shore.; 2. Of a wind, blowing from the land to the sea.; 3. At some distance from the shore; located in the sea away from the coast.
Oiler (also replenishment oiler or fleet tanker): A naval auxiliary ship with fuel tanks and dry cargo holds designed to replenish other ships with fuel and supplies while underway on the high seas.
Oilskins or oilies: Foul-weather clothing worn by sailors.
Old man, (The): Crew‍ 's slang for the captain (master or commanding officer) of a vessel.
Old salt: Slang for an experienced mariner.
On station: A ship's destination, typically an area to be patrolled or guarded.
On the hard: A boat that has been hauled and is now sitting on dry land.
Open registry: An organization that will register merchant ships owned by foreign entities, generally to provide a flag of convenience (q.v.).
Ordinary: See in ordinary.
Oreboat: Great Lakes term for a vessel primarily used in the transport of iron ore.
Orlop deck: The lowest deck of a ship of the line. The deck covering in the hold.
Outboard: 1. Situated outside the hull of a vessel.; 2. Situated within a vessel but positioned away (or farther away, when contrasted with another item) from her centerline (q.v.).; 3. Farther from the hull, e.g., The larger boat was tied up alongside the ship outboard of the smaller boat.; 4. Farther from the pier or shore, e.g., The tanker and cargo ship were tied up at the pier alongside one another with the tanker outboard of the cargo ship.; 5. An outboard motor (q.v.).; 6. A vessel fitted with an outboard motor.
Outboard motor: A motor mounted externally on the transom of a small boat. The boat may be steered by twisting the whole motor, instead of or in addition to using a rudder.
Outdrive: The lower part of a sterndrive (q.v.).
Outhaul: A line used to control the shape of a sail.
Outward bound: To leave the safety of port, heading for the open ocean.
Over-canvassed: To have too great a sail area up to safely maneuver in the current wind conditions.
Over-reaching: When tacking, holding a course too long.
Over the barrel: Adult sailors were flogged on the back or shoulders while tied to a grating, but boys were beaten instead on the posterior (often bared), with a cane or cat, while bending, often tied down, over the barrel of a gun, known as Kissing the gunner's daughter.
Overbear: To sail downwind directly at another ship, stealing the wind from its sails.
Overboard: Off or outside a vessel. If something or someone falls, jumps, or is thrown off of a vessel into the water, the object or person is said to have gone overboard. See "Man overboard!"
Overfalls: Dangerously steep and breaking seas due to opposing currents and wind in a shallow area, or strong currents over a shallow rocky bottom.
Overhead: The ceiling of any enclosed space below decks in a vessel, essentially the bottom of the deck above you.
Overhaul: Hauling the buntline ropes over the sails to prevent them from chafing.
Overwhelmed: Capsized or foundered.
Owner: traditional Royal Navy term for the Captain, a survival from the days when privately owned ships were often hired for naval service.
Ox-eye: A cloud or other weather phenomenon that may be indicative of an upcoming storm.

P

Packet, Packet boat, or packet ship: 1. Originally, a vessel employed to carry post office mail packets to and from British embassies, colonies and outposts.; 2. Later, any regularly scheduled ship, carrying passengers, as in packet trade.
Packet trade: Any regularly scheduled cargo, passenger and mail trade conducted by ship.
Packetman: A seaman aboard a ship engaged in packet trade.
Painter: A rope attached to the bow of a dinghy, usually used to tow dingy or handle it at dockside, or in water.
Panting: The pulsation in and out of the bow and stern plating as the ship alternately rises and plunges deep into the water
Parbuckle: A method of 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.
Parley: a discussion or conference, especially between enemies, over terms of a truce or other matters.
Parrel: A movable loop or collar, used to fasten a yard or gaff to its respective mast. Parrel still allows the spar to be raised or lowered and swivel around the mast. Can be made of wire or rope and fitted with beads to reduce friction.
Part brass rags: Fall out with a friend. From the days when cleaning materials were shared between sailors.
Passageway: Hallway of a ship.
Passenger-cargoman: A merchant ship configured primarily for the transportation of cargo but also for the transportation of at least some passengers.
Pay off: To let a vessel's head fall off from the wind (to leeward.)
Paying: Filling a seam (with caulking or pitch), lubricating the running rigging; paying with slush (q.v.), protecting from the weather by covering with slush. See also: the devil to pay. (French from paix, pitch)
Paymaster: The officer responsible for all money matters in RN ships including the paying and provisioning of the crew, all stores, tools and spare parts. See also: purser.
Peak: 1. The upper aftermost corner of a fore-and-aft sail; used in many combinations, such as peak-halyards, peak-brails, etc.; 2. The narrow part of a vessel's bow, or the hold within it.; 3. The extremity of an anchor fluke; the bill.
Pelagic: 1. Living in the open ocean rather than coastal or inland waters, (e.g., " a pelagic shark").; 2. Taking place in the open ocean (e.g., "pelagic fishing," "pelagic sealing").
Pendant: 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. Often used incorrectly when referring to a Pennant (flag).
Pennant: A long, thin triangular flag flown from the masthead of a military ship (as opposed to a burgee, the flags thus flown on yachts).
Picket boat: A boat on sentry duty, or one placed on a line forward of a position to warn against an enemy advance.
Pier: A raised structure, typically supported by widely spread piles or pillars, used industrially for loading and unloading commercial ships, receationally for walking and housing attractions at a seaside resort, or as a structure for use by boatless fishermen. The lighter structure of a pier contrasts with the more solid foundations of a quay or the closely spaced piles of a wharf. In North America, the term "pier" used alone connotes either a pier used (or formerly used) by commercial shipping or one used for fishing, while in Europe the term used alone connotes a recreational pier at a seaside resort.
Pier-head jump: When a sailor is drafted to a warship at the last minute, just before she sails.
Pilot: Navigator. A specially knowledgeable person qualified to navigate a vessel through difficult waters, e.g. harbour pilot etc.
PIM: Points (or plan) of intended movement. The charted course for a naval unit's movements.
Pinnace: 1. Pinnace (ship's boat), a small, light boat propelled by oars or a sail, used as a tender to larger vessels during the Age of Sail.; 2. Full-rigged pinnace, a small "race built" galleon, squared rigged with either two or three masts.; 3. In modern usage, any small boat other than a launch or lifeboat associated with a larger vessel.
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. The shape of the instrument is similar to that of a smoking pipe.
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.
Piping the side: A salute on the bos'n's pipe(s) performed in the company of the deck watch on the starboard side of the quarterdeck or at the head of the gangway, to welcome or bid farewell to the ship's Captain, senior officers and honoured visitors.
Piracy: An act of robbery or criminal violence at sea by the occupants of one vessel against the occupants of another vessel (thus excluding such acts committed by the crew or passengers of a vessel against others aboard the same vessel). Piracy is distinguished from privateering, which is authorized by national authorities and therefore a legitimate form of war-like activity by non-state actors.
Pirate: One who engages in an act of piracy.
Pitch: A vessel's motion, rotating about the beam/transverse axis, causing the fore and aft ends to rise and fall repetitively.
Pitchpole: To capsize a boat stern over bow, rather than by rolling over.
Plane: To skim over the water at high speed rather than push through it.
Plimsoll line (also national Load Line): A special marking, positioned amidships, that indicates the draft of the vessel and the legal limit to which the vessel may be loaded for specific water types and temperatures.
Plotting room: see transmitting station.
Point: A unit of bearing equal to one thirty-second of a circle, i.e., 11.25°. A turn of 32 points is a complete turn through 360°.
Point up: To change the direction of a sailboat so that it is more up wind. To bring the bow windward. Also called heading up. This is the opposite of falling off.
Points of sail: The course of a sailing vessel in relation to the direction of the wind, divided into six points: in irons (pointed directly into the wind), close hauled (sailing as close into the direction of the wind as possible), close reach (between close reach and beam reach), beam reach (perpendicular to the wind), broad reach (wind behind the vessel at an angle), and running downwind or running before the wind (the wind is behind the vessel).
Pontoon: A flat-bottomed vessel used as a ferry, barge, car float or a float moored alongside a jetty or a ship to facilitate boarding.
Poop deck: A high deck on the aft superstructure of a ship.
Pooped: 1. Swamped by a high, following sea.; 2. Exhausted.
Port: The left side of the boat. Towards the left-hand side of the ship facing forward (formerly Larboard). Denoted with a red light at night.
Port of registry: The port listed in a vessel‍ 's registration documents and lettered on her stern. Often used incorrectly as a synonym for "home port", meaning the port at which the vessel is based, but which may differ from her port of registry.
Port tack: When sailing with the wind coming from the port side of the vessel. Must give way to boats on starboard tack.
Porthole or port: an opening in a ship's side, esp. a round one for admitting light and air, fitted with thick glass and, often, a hinged metal cover, a window
Post-captain: an obsolete alternative form of the rank of captain in the Royal Navy; once achieved promotion thereafter was entirely due to seniority.
Powder hulk: A hulk used to store gunpowder.
Powder magazine: A small room/closet area in the hull of the ship used for storing gunpowder in barrels, or, "kegs", usually located centrally so as to have easy access to the grated loading area. Sometimes may be an enclosed closet with a door, so it can be locked and only the captain would have the key, similar to how rum is stored.
Predreadnought: Term used retrospectively after 1906 for a wide variety of steam battleships built between the 1880s and c. 1905 designed with only a few large guns for long-range fire, relying on an intermediate secondary battery used at shorter ranges for most of their offensive power, and having triple-expansion steam engines. They were rendered obsolete by the revolutionary dreadnought battleships which began to appear in 1906 and which differed from predreadnoughts in having steam turbine propulsion and an "all-big-gun" armament layout in which the ship‍ 's primary gun power resided in a primary battery of its largest guns intended for use at long range, with other gun armament limited to small weapons intended for defense against torpedo boats and other small warships.
Press gang: Formed body of personnel from a ship of the Royal Navy (either a ship seeking personnel for its own crew or from a 'press tender' seeking men for a number of ships) that would identify and force (press) men, usually merchant sailors into service on naval ships usually against their will.
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.
Principal Warfare Officer: PWO, one of a number of Warfare branch specialist officers.
Prison ship or prison hulk: A vessel used as a prison, often to hold convicts awaiting transportation to penal colonies; particularly common in the British Empire in the 18th and 19th centuries.
Private ship: In British usage, a commissioned warship in active service that is not being used as the flagship of a flag officer. The term does not imply in any way that the ship is privately owned.
Privateer: A privately owned ship authorised by a national power (by means of a #Letter of marque) to conduct hostilities against an enemy. Also called a private man of war.
Prize: A property captured at sea in virtue of the rights of war, as a vessel.
Prize crew: Members of a warship‍ 's crew assigned to man a vessel taken as a prize.
Propeller (fixed): A propeller mounted on a rigid shaft protruding from the hull of a vessel, usually driven by an inboard motor;
Propeller (folding): A propeller with folding blades, furling to reduce drag on a sailing vessel when not in use.
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.
Prow: a poetical alternative term for bows.
Puddening: Fibres of old rope packed between spars, or used as a fender.
Purchase: A mechanical method of increasing force, such as a tackle or lever.
Purser: The person who buys, stores and sells all stores on board ships, including victuals, rum and tobacco. Originally a private merchant, latterly a warrant officer.

Q

Quarterdeck: The aftermost deck of a warship. In the age of sail, the quarterdeck was the preserve of the ship's officers.
Queen's (King's) Regulations: The standing orders governing the British Royal Navy issued in the name of the current Monarch.
Quay: 1. A stone or concrete structure on navigable water used for loading and unloading vessels, generally synonymous with a wharf (q.v.), although the solid foundations of a quay contrast with the closely spaced piles of a wharf. When "quay" and "wharf" are used as synonyms, the term "quay" is more common in everyday speech in the United Kingdom, many Commonwealth countries, and the Republic of Ireland, while "wharf" is more commonly used in the United States.; 2. To land or tie up at a quay.
Quayside: 1. An area alongside a quay.; 2. Having the attribute of being alongside a quay, e.g., "The ship is moored quayside."

R

Rabbet or rebate /ˈræbət/: A groove cut in wood to form part of a joint.
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.
Rake: To incline from the perpendicular; something so inclined is raked or raking, e.g., a raked or raking stem, stern, mast, funnel, etc.
Ram: 1. A weapon consisting of an underwater prolongation of the bow of a vessel to form an armored beak, intended to be driven into the hull of an enemy vessel in order to puncture the hull and disable or sink that vessel.; 2. An armored warship of the second half of the 19th century designed to use such a weapon as her primary means of attack.; 3. To intentionally collide with another vessel with the intention of damaging or sinking her.; 4. To accidentally collide bow-first with another vessel.
Range clock: A clockwork device used aboard a warship to continuously calculate the range to an enemy ship.
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.
Rating: 1. In British usage, an enlisted member of a country's navy, i.e., all members of the navy who are not officers or warrant officers.; 2. In contemporary United States Navy and United States Coast Guard usage, the occupational specialty of an enlisted member of the service.
Ratlines: The rungs fastened between the shrouds permanently rigged from bulwarks and tops to the mast to form ladders enabling access to the topmasts and yards.
Razee: 1. A sailing ship that has been cut down to reduce the number of decks.; 2. To cut down a sailing ship to reduce the number of decks.
Reaching: Sailing across the wind: 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°). See also beating and running.
Reaching Sail: A specifically designed sail for tighter reaching legs. Reaching sails are often used in racing with a true wind angle of 35 to 95 degrees. They are generally used before the wind angle moves aft enough to permit spinnakers to be flown.
Ready about: A call to indicate imminent tacking (see going about).
Receiver of Wreck: A government official whose duty is to give owners of shipwrecks the opportunity to retrieve their property and ensure that law-abiding finders of wreck receive an appropriate reward.
Receiving hulk or receiving ship: A hulk used in harbor to house newly recruited sailors before they are assigned to a crew.
Red Duster: Traditional nickname for the Red Ensign, the civil ensign (flag) carried by United Kingdom civilian vessels.
Red-to-red: A passage of two vessels moving in the opposite direction on their port sides, so called because the red navigation light on one of the vessels faces the red light on the other vessel.
Reduced cat: A light version on the cat o'nine tails for use on boys; also called "boys' pussy".
Reef: 1. Reefing: 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.; 2. Reef: 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 flat lengths of braided cord attached by eyelets to a sail along the reef band, used to secure the excess fabric after reefing. Typically, a reef point consists of two lengths of cord which taper towards their ends—the narrow end of each is threaded through an eye in the wide end of the other and then the pair are rove through the eyelet in the reef band such that one length hangs before and the other abaft the sail.^[23]
Reef-bands: Long pieces of rough canvas sewed across the sails to give them additional strength.
Reef-tackles: Ropes employed in the operation of reefing.
Reefer: 1. A shipboard refrigerator.; 2. A refrigerated cargo ship, used to carry perishable goods that require refrigeration (also reefer ship)
Reeve: (Past tense rove) To thread a line through blocks in order to gain a mechanical advantage, such as in a block and tackle.
Regatta: A series of boat races, usually of sailboats or rowboats, but occasionally of powered boats.
Relative bearing: A bearing relative to the direction of the ship: the clockwise angle between the ship's direction and an object. See also absolute bearing and bearing.
Research vessel: A ship designed and equipped to carry out research at sea, especially hydrographic survey, oceanographic research, fisheries research, naval research, polar research, and oil exploration.
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.
Rigol: The rim or 'eyebrow' above a port-hole or scuttle.
Rip rap: A man-made pile of rocks and rubble often surrounding an off-shore lighthouse or as a base for an aid to navigation.
Roads: See roadstead.
Roadstead: A sheltered area outside a harbour where a ship can lie safe at anchor, also known as a roads.
Rode: The anchor line, rope or cable connecting the anchor chain to the vessel. Also Anchor Rode.
Rogue wave: A surprisingly large wave for a given sea state; formally, a wave whose height is more than twice the significant wave height (i.e., the mean of the largest third of waves in a wave record).
Roll: A vessel's motion rotating from side to side, about the fore-aft/longitudinal axis. Listing is a lasting, stable tilt, or heel, along the longitudinal axis. Roll is also an alternate name for the longitudinal axis (roll axis).
Roll-on/roll-off ship (also RORO or ro-ro): A vessel designed to carry wheeled cargo that can drive on and off the ship on its own wheels.
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.
Romper: In a convoy, a ship that breaks ranks and "romps" ahead.
Ropes, the: the lines in the rigging.
Rope's end: A summary punishment device.
Rope yarn: 1. A period, traditionally on Wednesday afternoons, when a tailor boarded a sailing warship while the vessel was in port; the crew was excused from most duties and had light duty mending uniforms and hammocks and darning socks. When the ship was at sea, the crew similarly was excused from most duties on Wednesday afternoons to engage in mending chores. Wednesday afternoons, like Sundays, thus were a more social time which allowed crewmen a rest from their normal duties, similar to a Sunday, and, because the crew used rope yarn for mending, Wednesday afternoon became known as rope yarn Sunday.; 2. After uniforms began to require less care, and through the mid-20th century, a period on Wednesday afternoon when naval crew members were excused from their regular duties to run personal errands.; 3. Since the mid-20th century, any period of free time when a naval crew is given early liberty or otherwise excused from its normally scheduled duties.
RORO or ro-ro: See roll-on/roll-off ship.
Rowlock /ˈrɒlək/: A bracket providing the fulcrum for an oar. Also see thole.
Royal: 1. In large sailing ships, a mast right above the topgallant mast.; 2. The sail of such a mast.
Rubbing strake: An extra plank fitted to the outside of the hull, usually at deck level, to protect the topsides.
Rudder: A steering device which can be placed aft, externally relative to the keel or compounded into the keel either independently or as part of the bulb/centerboard.
Rum-runner: see go-fast boat.
Rummage sale: A sale of damaged cargo (from French arrimage).
Run: 1. The stern of the underwater body of a ship from where it begins to curve upward and inward.; 2. A voyage.
Running before the wind or running: Sailing more than about 160° away from the wind. If directly away from the wind, it's a dead run.
Running gear: The propellers, shafts, struts and related parts of a motorboat.
Running rigging: Rigging used to manipulate sails, spars, etc. in order to control the movement of the ship. Cf. standing rigging.

S

Safe harbour: A harbour which provides safety from bad weather
Safe haven: A safe harbour, including natural harbours, which provide safety from bad weather or attack.
Sagging: When the trough of a wave is amidships, causing the hull to deflect so the ends of the keel are higher than the middle. The opposite of hogging.
Sail: 1. A piece of fabric attached to a vessel and arranged such that it causes the wind to drive the vessel along. It may be attached to the vessel via a combination of mast, spars, and ropes.; 2. The power harnessed by a sail or sails to propel a vessel.; 3. To use sail power to propel a vessel.; 4. A trip in a boat or ship, especially a sailboat or sailing ship.; 5. In American usage, a sail is a tower-like structure on the dorsal (topside) surface of submarines constructed since the mid-20th century which houses periscopes, access trunks for the bridge, etc.; called a fin in European and British Commonwealth countries. It differs from the conning tower of earlier submarines, which was similar in appearance to a sail or fin, but housed instruments and controls from which the periscopes were used to direct the submarine and launch torpedo attacks, functions not performed in a modern sail (or fin).
Sail loft: A large open space used by sailmakers to spread out sails.
Sail-plan: A set of drawings showing various sail combinations recommended for use in various situations.
Sailing skiff: see 'skiff'.
Sailmaker: A craftsman who makes and repairs sails, working either on shore in a sail loft or aboard a large, ocean-going sailing ship.
Sally ship: A method of freeing a vessel grounded on mud in which the crew forms a line and runs back and forth athwartships (q.v.) to cause her to rock back and forth, breaking the mud‍ 's suction and freeing her with little or no hull damage. When this is required, the crew is given the order Sally ship!
Saltie: Great Lakes term for a vessel that sails the oceans.
Salty dog: Slang for a sailor, especially for a seaman in the navy.
Sampan: A relatively flat bottomed Chinese wooden boat from 3.5 to 4.5 m long; some with a small shelter and may be used as permanent habitation on inland waters; generally used in coastal areas or rivers and as traditional fishing boats. It is unusual for a sampan to sail far from land as they do not have the means to survive rough weather.
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 and efficiency of a sail by expedient means (slacking the peak and tricing up the tack) without properly reefing, thus slowing boat speed. Also used in the past as a sign of mourning.
Scantlings: Dimensions of ships structural members, e.g., frame, beam, girder, etc.
Schooner: A type of sailing vessel characterized by the use of fore-and-aft sails on two or more masts with the forward mast being no taller than the rear masts, first used by the Dutch in the 16th or 17th century.
Schreecher: This is a specialty sail whose name comes from combining the names Spinnaker and Reaching sails and can be used as an upwind genoa sail, reaching sail or downwind sail.
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.; 3. An inland racing boat with no keel, a large sail plan, and a planing hull.
Screw: 1. Propeller.; 2. Propeller-driven (e.g., screw frigate, screw sloop).
Scud: A name given by sailors to 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: 1. An oar used for sculling.; 2. A boat propelled by sculling, generally for recreation or racing.
Sculling: A method of using oars to propel watercraft in which the oar or oars touch the water on both the port and starboard sides of the craft, or over the stern. On sailboats with transom-mounted rudders, forward propulsion can be made by a balanced side to side movement of the tiller, a form of sculling.
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 openings in the bulwarks.
Scuttle: A small opening, or lid thereof, in a ship's deck or hull.
Scuttlebutt: 1. A barrel with a hole in used to hold water that sailors would drink from. By extension (in modern naval usage), a shipboard drinking fountain or water cooler.; 2. Slang for gossip.
Scuttling: Making a hole in the hull of a vessel or opening seacocks, especially in order to sink a vessel deliberately.
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. Often in the form of a large bag made of heavy canvas. Also see drogue.
Sea chest: A watertight box built against the hull of the ship communicating with the sea through a grillage, to which valves and piping are attached to allow water in for ballast, engine cooling, and firefighting purposes. Also a wooden box used to store a sailor’s effects.
Sea state: The general condition of the free surface on a large body of water with respect to wind waves and swell at a certain location and moment, characterized by statistics, including the wave height, period, and power spectrum. The sea state varies with time, as the wind conditions or swell conditions change.
Sea trial: The testing phase of a boat, ship, or submarine, usually the final step in her construction, conducted to measure a vessel’s performance and general seaworthiness before her owners take delivery of her.
Seaboots: High waterproof boots for use at sea. In leisure sailing, known as sailing wellies.
Seacock: a valve in the hull of a boat.
Sealing: The hunting of seals.
Seaman: Generic term for sailor, or (part of) a low naval rank
Seaworthy: Certified for, and capable of, safely sailing at sea.
Second mate: Also called second officer, a licensed member of the deck department of a merchant ship, third – or on some ocean liners fourth – in command; a watchkeeping officer, customarily the ship‍ 's navigator. Other duties vary, but the second mate is often the medical officer and in charge of maintaining distress signaling equipment. On oil tankers, the second mate usually assists the chief mate with tank-cleaning operations.
Second officer: See second mate.
Self-sustaining: A merchant ship which is able to unload herself without any assistance from a harbor's facilities is self-sustaining, while a ship which requires the assistance of a harbor's facilities to unload herself is non-self-sustaining. Self-sustaining ships are more expensive to build, maintain, and operate than non-self-sustaining ships, but have the advantage of being able to operate in less-developed ports that lack the infrastructure necessary to unload ships.
Self-unloader: Great Lakes slang term for a vessel with a conveyor or some other method of unloading the cargo without shoreside equipment.
Sennet whip: A summary punitive implement
Sextant: Navigational instrument used to measure a ship's latitude.
Shaft alley: Section of a ship that houses the propulsion shaft, running from the engine room to the stuffing box.
Shakedown cruise: A cruise performed before a ship enters service or after major changes such as a crew change, repair, or overhaul during which the performance of the ship and her crew are tested under working conditions.
Shakes: Pieces of barrels or casks broken down to save space. They are worth very little, leading to the phrase "no great shakes".
Shanghaied: Condition of a crewman involuntarily impressed into service on a ship.
Sheer: The upward curve of a vessel's longitudinal lines as viewed from the side.
Sheer plan: In shipbuilding, a diagram showing an elevation of the ship's sheer viewed from the broadside.
Sheet: A rope used to control the setting of a sail in relation to the direction of the wind.
Shell (in the United Kingdom also fine boat): An extremely narrow, and often disproportionately long, rowing boat outfitted with long oars, outriggers to hold the oarlocks away from the boat, and sliding seats, specifically designed for racing or exercise.
Shelter deck: An upper deck having no overhead protection from the weather itself, but sheltering the deck below it.
Shift colors: Changing the flag and pennant display when a moored vessel becomes underweigh, and vice versa. A highly coordinated display that ships take pride in; the desired effect is that of one set of flags vanishing while another set flashes out at precisely the same time. Also, slang for changing out of one's Navy uniform into civilian clothes to go ashore. (The U.S. Navy's newsletter for retired personnel is nicknamed Shift Colors from this reason.)^[24]
Shift tides: Sighting the positions of the sun and moon using a sextant and using a nautical almanac to determine the location and phase of the moon and calculating the relative effect of the tides on the navigation of the ship.^[25]^[26]
Ship: 1. Noun – 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. Generally now used refers to 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.; 2. Verb – To bring something aboard swiftly, as in "Ship oars."
Ship-of-the-line: A type of sailing warship constructed from the 1600s through the mid-1800s to serve as part of the line of battle; the largest and most powerful warships of the era.
Ship over: Verb – To reenlist. When a sailor extends his or her service another term.
Ship rig
Ship-rigged ship: See full rigged ship.
Ship sloop: A type of sloop-of-war introduced in the 1740s which had three square-rigged masts (in contrast to the brig sloop introduced in the 1770s, which had two masts).
Ship's bell: Striking the ship's bell is the traditional method of marking time and regulating the crew's watches. Each bell (from one to eight) represents a 30-minute period since the beginning of a four-hour watch. For example, in the classical system, "Three bells in the morning watch" represents 90 minutes since the beginning of the morning watch, or 5:30am. "Eight bells" indicates the end of a watch.
Ship's biscuit: See hard tack.
Ship's company: The crew of a ship.
Ship's complement: The number of persons in a ship‍ 's crew, including officers.
Ship's husband: Once widely used term, now obsolete, for the man at a dockyard in charge of repairs to a ship. The term derived from the notion that the ship was a "lady" who needed to visit her "husband" when in need of repairs.
Shipwright: A person who designs, builds, and repairs ships, especially wooden ones .
Shipyard: A facility where ships or boats are built and repaired. Routinely used as a synonym for dockyard, although dockyard sometimes is associated more closely with a facility used for maintenance and basing activities, while shipyard sometimes is associated more closely with a facility used in construction.
Shoal: Shallow water that is a hazard to navigation.
Shoal draught: Shallow draught, making the vessel capable of sailing in unusually shallow water.
Shore leave: Free time given to officers and crew of a naval vessel when they are off duty and allowed to disembark and spend time on land. See also liberty.
Short stay: The relative slackness of an anchor chain; this term means somewhat slack, but not vertical nor fully extended.
Shorten: 1. To take in the slack of (a rope).; 2. To reduce (sail) by taking it in.
Shot across the bow: A shot fired close to and in front of a moving vessel to warn her to stop, often for boarding.
Shroud: A rope or cable serving to hold a mast up from side to side.
Shrouds: Standing rigging running from a mast to the sides of a ships to support the mast sideways. The shrouds work with the stays, which run forward and aft, to support the mast's weight.
Sick bay: The compartment reserved for medical purposes.
Sideboy: One of an even-numbered group of seamen posted in two rows on the quarterdeck when a visiting dignitary boards or leaves the ship, historically to help (or even hoist) him aboard.
Sidewheel: 1. A side-mounted paddle wheel used for propulsion by a paddle steamer.; 2. Propelled by a sidewheel (e.g., "sidewheel steamer").
Siren: A sound signal which uses electricity or compressed air to actuate either a disc or a cup shaped rotor.
Sister ship: A ship of the same class as, and therefore virtually identical in design and appearance to, another ship. Sister ships share an identical or nearly identical hull and superstructure layout, similar displacement, and roughly comparable features and equipment. Often, sister ships become more differentiated during their service lives as their equipment (and, in the case of military ships, their armament) are separately altered.
Skeg: A downward or sternward projection from the keel in front of the rudder. Protects the rudder from damage, and in bilge keelers may provide one "leg" of a tripod on which the boat stands when the tide is out.
Skiff: A small boat, traditionally a coastal or river craft, for leisure or fishing, with a single person or small crew. Sailing skiffs have developed into high performance competitive classes.
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.
Slack tide: That period between rising tide and falling tide. or that period between falling tide and rising tide when there is no tidal induced current.
Sloop: A small to mid-sized sailboat larger than a dinghy, with one mast bearing a main sail and head sail and located farther forward than the mast of a cutter.
Sloop-of-war: 1. In the 18th and 19th centuries, a small sailing warship carrying 18 or fewer guns with a single continuous gundeck.; 2. In the 18th and 19th centuries, any sailing warship bearing fewer than 20 guns.; 3. In the 19th-century United States Navy, the term used for the type of sailing warship known in other navies as a corvette.; 4. In the early and mid-20th century, a small ocean-going warship not intended for fleet deployments, used instead for convoy escort, gunboat duties, etc.
Slop chest: A ship's store of merchandise, such as clothing, tobacco, etc., maintained aboard merchant ships for sale to the crew.
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. In the Royal Navy the perquisite of the cook who could sell it or exchange it (usually for alcohol) with other members of the crew. Used for greasing parts of the running rigging of the ship and therefore valuable to the master and bosun.
Slush fund: The money obtained by the cook selling slush ashore. Used for the benefit of the crew (or the cook).
Smack: A traditional fishing boat used off the coast of England and the Atlantic coast of America for most of the 19th century and in small numbers up to the mid-20th century. Originally a cutter-rigged sailing boat, after about 1865 lengthened and given a ketch rig. Some had a topsail on the mizzen mast, others a bowsprit carrying a jib.
Small bower (anchor): The smaller of two anchors carried in the bow.
Snotty: A midshipman (Royal Navy slang.)^[27]
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.
SOG: Speed over ground, speed of the vessel relative to the Earth (and as shown by a GPS). Referenced on many fishing forums.
Sonar: 1. An acronym for SOund Navigation And Ranging, a method of using sound pulses to detect, range, and sometimes image underwater targets and obstacles or the bed of the sea. Also see echo sounding and ASDIC.; 2. The equipment used to conduct such searches, ranging, and imaging.
Sounding: Sounding.
Measuring the depth of the water. Traditionally done by swinging the lead, now commonly by echo sounding.
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.
Spanker: A fore-and-aft or gaff-rigged sail on the aft-most mast of a square-rigged vessel and the main fore-and-aft sail (spanker sail) on the aft-most mast of a (partially) fore-and-aft rigged vessel such as a schooner, a barquentine, and a barque.
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 (see Jigger-mast).
Spar: A wooden, in later years also iron or steel pole used to support various pieces of rigging and sails. The big five-masted full-rigged tall ship Preussen (German spelling: Preußen) had crossed 30 steel yards, but only one wooden spar—the little gaff of its spanker sail.
Spar torpedo: A weapon consisting of a bomb placed at the end of a long spar and attached to a boat.
Speaking tube: see communication tube.
Spider band or Spider hoop: An iron band around the base of a mast which holds a set of iron belaying pins.
Spindrift: Finely divided water swept from crest of waves by strong winds.
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.
Sponson: A projection from the side of a vessel for protection, stability, or the mounting of equipment such as armaments or lifeboats. A sponson that extends a hull dimension at or below the waterline serves to increase flotation or add lift when underway.
Sponsor: The person, traditionally a woman, who christens a ship at its launching ceremony.
Spotting top: A platform on a mast used to aid in gun laying.
Spring: A line used parallel to that of the length of a craft, to prevent fore-aft motion of a boat, when moored or docked.
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.
Splice the mainbrace: A euphemism, it is an order given aboard naval vessels to issue the crew with a drink, traditionally grog. The phrase splice the mainbrace is used idiomatically meaning to go ashore on liberty, intending to go out for an evening of drinking.
Spreader: A spar on a sailboat used to deflect the shrouds to allow them to better support the mast.
Spurling pipe: A pipe that connects to the chain locker, from which the anchor chain emerges onto the deck at the bow of a ship.
Squadron: 1. In general, any significant group of warships which is considered too small to be designated a fleet, but otherwise not strictly defined by size. In some navies, the term flotilla may be used instead of or in addition to "squadron" to describe a significant group of warships smaller than a fleet.; 2. Such a group of warships assigned to and named after a particular ocean, sea, or geographical region, commanded by an admiral who may be the naval commander-in-chief in that theatre, e.g., the Asiatic Squadron, the North Atlantic Squadron, etc.; generally synonymous with similar naval formations known as stations (q.v.).; 3. During the Age of Sail, a temporary sub-division of a fleet.; 4. A temporary detachment of ships from a fleet.; 5. Especially in the late 19th and early 20th centuries, a permanent battle formation of a fleet, equipped and trained to operate as a tactical unit under the overall command of the fleet or when detached from the fleet.; 6. Especially in modern usage, an administrative naval command responsible for the manning, training, supply, and maintenance of a group of ships or submarines but not for directing their operations at sea.
Square: To place at right angles with the mast or keel and parallel to the horizon e.g., "to square the yards."
Square meal: A sufficient quantity of food. Meals on board ship were served to the crew on a square wooden plate in harbor or at sea in good weather. Food in the Royal Navy was invariably better or at least in greater quantity than that available to the average landsman. However, while square wooden plates were indeed used on board ship, there is no established link between them and this particular term. The OED gives the earliest reference from the U.S. in the mid-19th century.
Square rig: A generic type of sail and rigging arrangement in which the primary driving sails are carried on yards which are perpendicular, or square, to the keel of the vessel and to the masts. A ship mainly so rigged is said to be square-rigged.
Square rigger: A ship which is square-rigged.
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 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.
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, and thus its effective draught is increased.
S.S. (or SS): Prefix for "Steam Ship", used before a ship‍ 's name.
Stack (also funnel): See funnel.
Stanchion: vertical post near a deck's edge that supports life-lines. A timber fitted in between the frame heads on a wooden hull or a bracket on a steel vessel, approx one meter high, to support the bulwark plank or plating and the rail.
Stand (past tense stood): Of a ship or its captain, to steer, sail, or steam, usually used in conjunction with a specified direction or destination, e.g., The ship stood out of the harbor or The ship stood toward the east or The ship stood toward the missing vessel's last known position.
Stand-on (vessel): A vessel directed to keep her course and speed where two vessels are approaching one another so as to involve a risk of collision.
Standing rigging: Rigging which is used to support masts and spars, and is not normally manipulated during normal operations. Cf. running rigging.
Starboard: The right side of the boat. 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.
Starboard tack: When sailing with the wind coming from the starboard side of the vessel. Has right of way over boats on port tack.
Starter: A rope used as a punitive device. See teazer, togey.
Stateroom: 1. A superior cabin for a vessel‍ 's officer.; 2. In American usage, also a private passenger cabin in a vessel
Station: 1. In chiefly 19th- and early 20th-century usage, a naval formation under a commander-in-chief who controls all naval operations, and sometimes all naval shore shore facilities, within a specified geographic area (e.g., the China Station, the East Indies Station, etc.), sometimes synonymous with squadron (q.v.).; 2. In Newfoundland, a harbour or cove with a foreshore suitable for a facility to support nearby fishing.; 3. Naval station, a naval base; a naval air station is a base for naval aircraft.; 4. Coaling station, a facility that supplies ships with coal.
Stay: 1. A strong rope supporting a mast, and leading from the head of one mast down to some other mast or other part of the vessel; rigging running fore (forestay) and aft (backstay) from a mast to the hull. The stays support a mast's weight forward and aft, while the shrouds support its weight from side to side.; 2. To incline forward, aft, or to one side by means of stays, e.g., to stay a mast .; 3. To tack; put on the other tack, e.g., to stay ship.; 4. To change; tack; go about; be in stays, as a ship..; 5. A station or fixed anchorage for vessels.; 6. In stays or hove in stays: in the act of going about while tacking.; 7. Miss stays an unsuccessful attempt to tack.
Staysail: A sail whose luff is attached to a forestay.
Steamer: A vessel equipped with steam propulsion. Also steamboat or steamship.
Steerage: 1. The effect of the helm on a vessel; the act of steering a vessel.; 2. 19th- and early 20th-century term for the section of a passenger ship that provided inexpensive accommodation with no individual cabins.
Steerageway: The minimum speed at which a vessel will answer the helm, below which she cannot be steered. Speed sufficient for the rudder to "bite."
Steering flat: In a vessel, the compartment containing the steering gear.
Steering oar or steering board: A long, flat board or oar that went from the stern to well underwater, used to steer vessels before the invention of the rudder. Traditionally on the starboard side of a ship (the "steering board" side).
Steeve: 1. A spar or derrick with a block at one end, used for stowing cargo.; 2. To incline upwards at an angle (esp. of a bowsprit) rather than lie horizontally; to set at a particular upwards incline
Stem: The extension of keel at the forward end 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 rail to the taffrail.
Stern chaser: See chase gun.
Stern tube: 1. The tube under the hull to bear the tailshaft for propulsion (usually at stern).; 2. A torpedo tube mounted in the stern of a submarine.
Sterndrive: A propeller drive system similar to the lower part of an outboard motor extending below the hull of a larger power boat or yacht, but driven by an engine mounted within the hull. Unlike a fixed propeller (but like an outboard), the boat may be steered by twisting the drive. Also see inboard motor and outboard motor.
Sternwalk: An external walkway or gallery for the use of officers installed on the stern chiefly of British warships until the early 20th century.
Sternway: The reverse movement of a boat or watercraft through the water.
Steward: A member of a vessel‍ 's crew involved in commissary duties or in personal services to passengers or other crew members.
Stood: See Stand.
Storeship: 1. During the Age of Sail and immediately afterwards, a captured ship used to stow supplies and other goods for naval purposes.; 2. Since the mid-20th century, a type of naval ship which provides supplies such as frozen, chilled' and dry provisions and propulsion and aviation fuel to warships which are at sea for an extended period of time. In some navies, synonymous with replenishment oiler, fleet replenisher, or fleet tanker.
Strake: (archaic) A continuous line of plates or planks running from bow to stern that contributes to a vessel's skin. The planks or plates next to the keel are called the garboard strakes; the next, or the heavy strakes at the bilge, are the bilge strakes; the next, from the water line to the lower port sill, the wales; and the upper parts of the sides, the sheer strakes.
Strike: 1. To haul down or lower (a flag, mast, etc.).; 2. To surrender the vessel to the enemy, from strike the colors.; 3. To remove a naval vessel‍ 's name from a country's naval register (after which the vessel is considered stricken).
Strike the colors: To surrender the vessel to an enemy, from the custom during the Age of Sail of lowering the vessel‍ 's ensign to indicate that she is surrendering.
Stopper knot: A knot tied in the end of a rope, usually to stop it passing through a hole; most commonly a figure-eight knot.
Stove or Stove in: (past tense of stave, often applied as present tense) to smash inward, to force a hole or break in, as in a cask, door or other (wooden) barrier.
Stow: to store, or to put away e.g. personal effects, tackle, or cargo.
Stowage: the amount of room for storing materials on board a ship.
Stowaway: A trespasser on a ship; a person aboard a ship without permission and/or without payment, and usually boards undetected, remains hidden aboard, and jumps ship just before making port or reaching a port's dock; sometimes found aboard and imprisoned in the brig until the ship makes port and the prisoner can be transferred to the police or military.
Straggler: In a convoy, a ship that is unable to maintain speed and falls behind.
Strake: One of the overlapping boards in a clinker built hull.
Stretcher: an inclined foot rest, attached to the boat, to which a rower may place and in some instances (usually in competition) attach his feet.
Studding-sails /ˈstʌnsəl/: Long and narrow sails, used only in fine weather, on the outside of the large square sails.
STW: Speed through (the) water, speed of the vessel relative to the surrounding water (and as shown by a Log). Used in navigation.
Sunfish: A personal-sized, beach-launched sailing dinghy with a pontoon-type hull, daggerboard, and lateen sail mounted to an un-stayed mast.
Superstructure: The parts of the ship or a boat, including sailboats, fishing boats, passenger ships, and submarines, that project above her main deck. This does not usually include its masts or any armament turrets.
Surge: A vessel's transient motion in a fore and aft direction.
Survey vessel: Any type of ship or boat that is used for mapping a body of water's bottom, benthic zone, full water column, and surface for purposes of hydrography, general oceanography, marine salvage, dredging, marine archaeology, or the study of marine habitats.
Sway: 1. A vessel's lateral motion from side to side.; 2. (v) To hoist: "Sway up my dunnage".
Sweep: A long oar used to steer an unpowered lighter.
Swigging: To take up the last bit of slack on a line such as a halyard, anchor line or dockline by taking a single turn round a cleat and alternately heaving on the rope above and below the cleat while keeping the tension on the tail.
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 lamp: Telling sea stories. Referring to lamps slung from the deckhead which swing while at sea. Often used to indicate that the story teller is exaggerating.
Swinging the lead: 1. Measuring the depth of water beneath a ship using a lead-weighted sounding line. Regarded as a relatively easy job, thus:; 2. Feigning illness etc to avoid a hard job.

T

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.
Tack: 1. A leg of the route of a sailing vessel, particularly in relation to tacking (q.v.) and to starboard tack and port tack (also q.v.).; 2. Hard tack: q.v..; 3. The front bottom corner of a sail.
Tacking: 1. Zig-zagging so as to sail directly towards the wind (and for some rigs also away from it).; 2. Going about (q.v.).
Tacking duels: In sailboat racing on an upwind leg of the race course the complex maneuvers of lead and overtaking boats to vie for the aerodynamic advantage of clear air. This results from the ongoing strategy of the lead boat's effort to keep the following boat(s) in the blanket of disturbed bad air he is creating.
Tactical diameter: The perpendicular distance between a ship's course when the helm is put hard over and her course when she has turned through 180 degrees; the ratio of the tactical diameter divided by the ship's length between perpendiculars gives a dimensionless parameter which can be used to compare the maneuverability of ships.
Taffrail: A rail at the stern of the boat that covers the head of the counter timbers.
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.
Taking the wind out of his sails: To sail in a way that steals the wind from another ship. cf. overbear.
Tally: The operation of hauling aft the sheets, or drawing them in the direction of the ship's stern.
Tanker (also tank ship or tankship): A ship designed to transport liquids in bulk.
Target ship: A vessel, typically an obsolete or captured warship, used for naval gunnery practice or for weapons testing. The term includes both ships intended to be sunk and ships intended to survive and see repeated use as a target.
Task Force: Temporary naval organisations composed of particular ships, aircraft, submarines, military land forces, or shore service units, assigned to fulfill certain missions. Seemingly drawn originally from Royal Navy heritage, the emphasis is placed on the individual commander of the unit, and references to 'CTF' are common for "Commander Task Force".
Tattle Tale: Light cord attached to a mooring line at two points a few inches apart with a slack section in between (resembling an inch-worm) to indicate when the line is stretching from the ship’s rising with the tide. Obviously only used when moored to a fixed dock or pier and only on watches with a flood tide.
Tell-tale (sometimes tell-tail): A light piece of string, yarn, rope or plastic (often magnetic audio tape) attached to a stay or a shroud to indicate the local wind direction. They may also be attached to the surface and/or the leech of a sail to indicate the state of the air flow over the surface of the sail. They are referenced when optimizing the trim of the sails to achieve the best boat speed in the prevailing wind conditions. (See dogvane)
T.E.V. (or TEV): Prefix for "Turbo-Electric Vessel," used before a ship‍ 's name.
Third mate: Also called the third officer, a licensed member of the deck department of a merchant ship, fourth – or on some ocean liners fifth – in command; a watchkeeping officer, customarily also the ship's safety officer, responsible for the ship‍ 's firefighting equipment, lifeboats, and other emergency systems. Other duties of the third mate vary depending on the type of ship, its crewing, and other factors.
Third officer: See third mate.
Thole: Vertical wooden peg or pin inserted through the gunwale to form a fulcrum for oars when rowing. Used in place of a rowlock.
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.
Thwart /ˈθwɔrt/: A bench seat across the width of an open boat.
Timoneer: From the French timonnier, is a name given, on particular occasions, to the steersman of a ship.
Tinclad: A lightly armored steam-powered river gunboat used by the United States Navy during the American Civil War (1861–1865).
Tingle: A thin temporary patch.
Tiller: a lever used for steering, attached to the top of the rudder post. Used mainly on smaller vessels, such as dinghies and rowing boats.
Toe-rail: A low strip running around the edge of the deck like a low bulwark. It may be shortened or have gaps 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.
Tompion: A block of wood inserted into the barrel of a gun on a 19th-century warship to keep out the sea spray; also used for covers for the ends of the barrels of more modern ships' guns, the larger of which are often adorned with the ship's crest or other decoration.
Tonnage: 1. Deadweight tonnage, the total weight of a vessel, mostly without payload.; 2. Displacement tonnage, the total weight of a vessel.; 3. Gross register tonnage, the total internal volume of a vessel, with one gross register ton equal to 100 cubic feet (2.8316846592 cubic meters).; 4. Gross tonnage, a function of the volume of all of a ship‍ 's internal spaces.; 5. Lightship or lightweight tonnage, the weight of a ship without any fuel, cargo, supplies, water, passengers, etc. on board.; 6. Net register tonnage, the volume of cargo a vessel can carry.; 7. Net tonnage, the volume of all cargo spaces on a ship.; 8. Thames Measurement tonnage, the volume of a small vessel calculated based on her length and beam.
Top: The platform at the upper end of each (lower) mast of a square-rigged ship, typically one-fourth to one-third of the way up the mast. The main purpose of a top is to anchor the shrouds of the topmast that extends above it. See also fighting top.
Topgallant: The mast or sails above the tops. (See topgallant mast and topgallant sail.)
Topman: A crewmember stationed in a top.
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: a line which is part of the rigging on a sailing boat; it applies upward force on a spar or boom. The most common topping lift on a modern sailing boat is attached to the boom
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
Torpedo: 1. Prior to about 1900, the term for a variety of explosive devices designed for use in water, including mines, spar torpedoes and, after the mid-19th century, "automotive," "automobile," "locomotive," or "fish" torpedoes (self-propelled weapons which fit the modern definition of "torpedo").; 2. Since about 1900, a term used exclusively for a self-propelled weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with its target or in proximity to it.
Touch and go: 1. The bottom of the ship touching the bottom, but not grounding.; 2. Stopping at a dock or pier for a very short time without tying up, to let off or take on crew or goods.; 3. Practice of aircraft on aircraft carriers touching the carrier deck and taking off again without dropping hooks.
Towing: The operation of drawing a vessel forward by means of long lines.
Traffic Separation Scheme: Shipping corridors marked by buoys which separate incoming from outgoing vessels. Improperly called Sea Lanes.
Trailboard: A decorative board at the bow of a vessel, sometimes bearing the vessel's name.
Training ship: A ship used to train students as sailors, especially a ships employed by a navy or coast guard to train future officers. The term refers both to ships used for training at sea and to old, immobile hulks used to house classrooms.
Tramp freighter: A cargo ship engaged in the tramp trade.
Tramp steamer: A steamship engaged in the tramp trade.
Tramp trade: Shipping trade on the spot market in which the vessels involved do not have a fixed schedule or itinerary or published ports of call. This contrasts with freight liner service, in which vessels make regular, scheduled runs between published ports.
Tramper: A vessel engaged in the tramp trade.
Transmitting station: British term for a room located in the interior of a ship containing computers and other specialised equipment needed to calculate the range and bearing of a target from information gathered by the ship's spotters and range finders. These were designated "plotting rooms" by the United States Navy.^[29]
Transom: The aft “wall” of the stern; often the part to which an outboard unit or the drive portion of a sterndrive is attached. A more or less flat surface across the stern of a vessel. Dinghies tend to have almost vertical transoms, whereas yachts’ transoms may be raked forward or aft.
Transport: See troopship.
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".
Trawler: 1. Commercial trawler, a fishing boat that uses a trawl net or dragnet to catch fish.; 2. A fisherman who uses a trawl net.; 3. Naval trawler, a converted trawler, or boat built in that style, used for naval purposes.; 4. Recreational trawler, a pleasure boat built in the style of a trawler.
Trice: To haul and tie up by means of a rope.
Trick: A period of time spent at the wheel ("my trick's over").
Trim: 1. Relationship of ship's hull to waterline.; 2. Adjustments made to sails to maximize their efficiency.
Trimaran: A vessel with three hulls.
Trimmer, sometimes Coal trimmer: person responsible for ensuring that a vessel remains in 'trim' (that the cargo and fuel are evenly balanced). An important task on a coal-fired vessel, as it could get 'out-of-trim' coal is consumed.
Trooping: Operating as a troopship.
Troopship (also troop ship, troop transport, or trooper): A ship used to carry soldiers. Troopships are not specially designed for military operations and unlike landing ships cannot land troops directly onto a shore; instead they unload troops at a harbor or onto smaller vessels for transportation to shore.
True bearing: An absolute bearing (q.v.) using true north.
True north: The direction of the geographical North Pole.
Truss: The rope or iron used to keep the center of a yard to the mast.
Tug or tugboat: A boat that maneuvers other vessels by pushing or towing them. Tugs are powerful for their size and strongly built, and some are ocean-going.
Tumblehome: Hull shape, when viewed in a transverse section, where the widest part of the hull is someway below deck level.
Turn: A knot passing behind or around an object.
Turn To (Two): A term meaning "Get to work," often hand-signed by two fingers and hand motion in turning fashion.
Turnbuckle: see bottlescrew.
Turret: 1. Originally (in the mid-to-late 19th century), an enclosed armored rotating cylindrical box mounting guns which fired through gunports, the turret rotating over a bearing mounted on a ship's deck or within her hull. Turret-equipped ships contrasted sharply with those equipped with barbettes, which in the second half of the 19th century were open-topped armored rings over which rotating gun(s) mounted on a turntable could fire.; 2. Since the late 19th century, an enclosed armored rotating gunhouse mounted above a barbette, with the gun(s) and their rotating turntable mounted in the barbette protected by the gunhouse; in 20th- and 21st-century usage, this generally is any armored, rotating gun installation on a warship.
Turtleback deck: A deck that has slight positive curvature when viewed in cross-section. The purpose of this curvature is usually to shed water, but in warships it also functions to make the deck more resistant to shells.
Turtling: In dinghy sailing especially (but can include other boats), a boat is said to be turtling or to turn turtle when the boat is fully inverted with the mast pointing down to the lake bottom or seabed.^{[upper-alpha 1]} ^[31]^[32]
Tweendeck: A deck on a general cargo ship located between the main deck (or weather deck) and the hold space. A general cargo ship may have one or two tweendecks (or none at all).
Tweendeck space: The space on a tweendeck available for carrying cargo or other uses.
Tweendecker: A general cargo ship equipped with one or more tweendecks.
Two six heave: Royal Navy slang term meaning to pull. Originally a sailing navy term referring to the two members of a gun crew (numbers two and six) who ran out the gun by pulling on the ropes that secured it in place.
Tye: A chain or rope used for hoisting or lowering a yard. A tye runs from the horizontal center of a given yard to a corresponding mast and from there down to a tackle. Sometimes specifically called a chain tye or a rope tye.

U

Unassisted sailing: A voyage, usually singlehanded, with no intermediate port stops or physical assistance from external sources.
Under the weather: Serving a watch on the weather side of the ship, exposed to wind and spray.
Under way or underway: A vessel that is moving under control: that is, neither at anchor, made fast to the shore, aground nor adrift. Way refers to speed sufficient to steer with the rudder. "Under weigh" is an erroneous synonym.
Underwater hull or underwater ship: The underwater section of a vessel beneath the waterline, normally not visible except when in drydock or (historically), careened.
Underway replenishment: A method employed by navies to transfer fuel, munitions, and stores from one ship to another while under way. Sometimes abbreviation as UNREP.
Unship: 1. To remove from a vessel.; 2. To remove an oar or mast from its normal position
Up-and-down: The relative slackness of an anchor chain where the anchor chain is slack and hangs vertically down from the hawsepipe.
Up-behind: Slack off quickly and run slack to a belaying point. This order is given when a line or wire has been stopped off or falls have been four-in-hand and the hauling part is to be belayed.
Upbound: 1. A vessel traveling upstream.; 2. Westward-traveling vessels in the Great Lakes region (terminology as used by the St. Lawrence Seaway Development Corporation).
Upper-yardmen: Specially selected personnel destined for high office.

V

V-hull: The shape of a boat or ship in which the contours of the hull come in a straight line to the keel.
Vang: 1. A rope (line) leading from gaff to either side of the deck, used to prevent the gaff from sagging.; 2. See boom vang.
Vanishing angle: The maximum degree of heel after which a vessel becomes unable to return to an upright position.
Vessel: Any craft designed for transportation on water, such as a ship or boat.
Voice pipe or voice tube: see communication tube.
Voyage: 1. A long journey by ship.; 2. To go on such a journey.

W

Wake: Turbulence behind a vessel. Not to be confused with wash.
Waft: A signal flag on a vessel.
Waist: the central deck of a ship between the forecastle and the quarterdeck.^[33]
Wale: Any of the strong and thick planks running length-wise along a vessel, forming the lower part of the vessel's sides.
Wardroom: 1. The living quarters of a naval ship designated for the use of commissioned officers other than the captain.; 2. A collective term for the commissioned officers of a naval ship excluding her captain; e.g., The captain rarely referred to his wardroom for advice, and this led to their discontent.
Warp: 1. To move a vessel by hauling on a line or cable that is fastened to an anchor or pier; especially to move a sailing ship through a restricted place such as a harbor.; 2. A line or cable used in warping a ship.
Wash: The waves created by a vessel. Not to be confused with wake.
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, etc.
Waterline: The line where the hull of a ship meets the water‍ 's surface.
Watersail: A sail hung below the boom on gaff rig boats for extra downwind performance when racing.
Waterway: 1. Waterway, a navigable body of water.; 2. A strake of timber laid against the frames or bulwark stanchions at the margin of a laid wooden deck, usually about twice the thickness of the deck planking.
Way: Speed, progress, or momentum, or more technically, the point at which there is sufficient water flow past a vessels rudder for it to be able to steer the vessel (i.e., the rudder begins to "bite," sometimes also called "steerage way.") To make way is to move; to "have way on" or "to have steerage way" is to have enough speed to control the vessel with its rudder; to lose way is to slow down or to not have enough speed to control with the rudder.
Way-landing: An intermediate stop along the route of a steamboat.
Waypoint: A location defined by navigational coordinates, especially as part of a planned route.
Wearing ship: Tacking away from the wind in a square-rigged vessel. See also gybe.
Weather deck: Whichever deck is that exposed to the weather—usually either the main deck or, in larger vessels, the upper deck.
Weather gage or weather gauge or weather-beam: Favorable position over another sailing vessel with respect to the wind.
Weather ship: A ship stationed in the ocean as a platform for surface and upper air meteorological observations for use in weather forecasting.
Weather side: The side of a ship exposed to the wind.
Weatherly: A ship that is easily sailed and maneuvered; makes little leeway when sailing to windward.
Weigh anchor: To heave up (an anchor) preparatory to sailing.
Well: Place in the ship's hold for pumps.
Well-found: Properly set up or provisioned.
Wetted area: In sailboating, portion of the hull immersed in water.
Whaleboat: 1. A type of open boat that is relatively narrow and pointed at both ends, enabling it to move either forwards or backwards equally well.; 2. On modern warships, a relatively light and seaworthy boat for transport of ship‍ 's crew.; 3. A type of vessel designed as a lifeboat or "monomoy" used for recreational and competitive rowing in the San Francisco Bay area and coastal Massachusetts.; 4. Informally, any whaler of any size.; 5. Informally, any vessel engaged in whale watching.
Whaler: 1. A specialized vessel designed for catching or processing whales.; 2. A person engaged in the catching or processing of whales.
Wharf: A structure on the shore of a harbor or on the bank of a river or canal where ships may dock to load and unload cargo or passengers. Such a structure includes one or more berths (i.e., mooring locations), and may also include piers, warehouses, or other facilities necessary for handling the ships. The term "wharf' is generally synonymous with "quay" (q.v.), although the solid foundations of a quay contrast with the closely spaced piles of a wharf. When "quay" and "wharf" are used as synonyms, the term "quay" is more common in everyday speech in the United Kingdom, many Commonwealth countries, and the Republic of Ireland, while "wharf" is more commonly used in the United States.
Wheel or ship's wheel: The usual steering device on larger vessels: a wheel with a horizontal axis, connected by cables to the rudder.
Wheelhouse: Location on a ship where the wheel is located; also called pilothouse or bridge.
Whelkie: A small sailing pram.
Wherry: A type of boat traditionally used for carrying cargo or passengers on rivers and canals in England, particularly on the River Thames and the Norfolk and Suffolk Broads.
Whiff: A chiefly British term for a narrow clinker-built skiff having outriggers, for one oarsman.
Whiskers: Spreaders from the bows to spread the bowsprit shrouds.
Whiskerstay: One of the pair of stays that stabilize the bowsprit horizontally affixed to forward end of the bowsprit and just aft the stem.
White horses or whitecaps: Foam or spray on wave tops caused by stronger winds (usually above Force 4).
Wide berth: To leave room between two ships moored (berthed) to allow space for maneuver.
Whipstaff: A vertical lever connected to a tiller, used for steering on larger ships before the development of the ship's wheel.
Wind-over-tide: Sea conditions with a tidal current and a wind in opposite directions, leading to short, heavy seas.
Windage: Wind resistance of the boat.
Windbound: A condition wherein the ship is detained in one particular station by contrary winds.
Windjammer: A large iron- or steel-hulled square-rigged sailing ship of the late 19th and early 20th centuries with three, four, or five masts , built mainly between the 1870s and 1900 to carry cargo on long voyages.
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).
Windsail: A wide tube or funnel of canvas, used to convey a stream of air into the lower compartments of a ship for ventilation.
Windward: In the direction that the wind is coming from.
Wing: An extension on the side of a vessel. A bridge wing is an open-air extension of the bridge to port or starboard, intended for use in signaling.
Working up: Training, usually including gunnery practice.
Worm, parcel and serve: To protect a section of rope from chafing by: laying yarns (worming) to fill in the cuntlines, wrapping marline or other small stuff (serving) around it, and stitching a covering of canvas (parceling) over all.

Y

Yacht: A recreational boat or ship; the term includes sailing yachts, motor yachts, and steam yachts.
Yard: 1. Yard: The horizontal spar from which a square sail is suspended.; 2. A dockyard or shipyard.
Yard number: Each shipyard typically numbers the ships that it has built in consecutive order. One use is to identify the ship before a name has been chosen.
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).
Yarr: Acknowledgement of an order, or agreement. Also aye, aye.
Yaw: A vessel's rotational motion about the vertical axis, causing the fore and aft ends to swing from side to side repetitively.
Yawl: A fore-and-aft rigged sailing vessel with two masts, main and mizzen, the mizzen stepped abaft the rudder post.
Yawl boat: A rowboat on davits at the stern of the boat.

Notes

↑ However, "to turn turtle" means putting a turtle on its back by grabbing it by the flipper, and conversely is used to refer to a vessel that has turned upside down, or which has cast off its crew. Smyth, W. H.; Belcher, E. (1867). The sailor's word-book: An alphabetical digest of nautical terms, including some more especially military and scientific ... as well as archaisms of early voyagers, etc. London: Blackie and Son. pp. 702–703.

References

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