Glossary of nautical terms

This is a 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.

A

aback
A sail is aback when the wind fills it from the opposite side to the one normally used to move the vessel forward. On a square-rigged ship, any of the square sails can be braced round to be aback. The purpose may be to reduce speed (such as when a ship-of-the-line is keeping station with others), to heave to or to assist moving the ship's head through the eye of the wind when tacking. A sudden wind shift can cause a square-rigged vessel to be "caught aback" with all sails aback. This is a dangerous situation that risks serious damage. In a fore-and-aft-rigged vessel, a headsail is backed either by hauling it across with the weather sheet or by tacking without releasing the sheet. It is used to heave to or to assist with tacking. [1] [2]
abaft
Toward the stern, relative to some object (e.g. "abaft the cockpit").
abaft the beam
Farther aft than the beam: a relative bearing of greater than 90 degrees from the bow (e.g. "two points abaft the beam, starboard side" 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"). [3]
abandon ship
An imperative to leave the vessel immediately, usually in the face of some imminent overwhelming danger. [4] It is an order issued by the Master or a delegated person in command, and must be a verbal order. 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 is customarily followed by a command to "man the lifeboats" or life rafts. [4] [5]
abeam
On the beam, a relative bearing at right angles to the ship's keel. [6]
able seaman (AB)

Also able-bodied seaman.

A merchant seaman qualified to perform all routine duties, or a junior rank in some navies.
aboard
On or in a vessel. Synonymous with "on board". See also close aboard.
about
To change the course of a ship by tacking. "Ready about" is the order to prepare for tacking. [7]
above board
On or above the deck; in plain view; not hiding anything. Pirates would hide their crews below decks, thereby creating the false impression that an encounter with another ship was a casual matter of chance. [8]
above-water hull
The hull section of a vessel above the waterline; the visible part of a ship. See also topsides.
absentee pennant
A special pennant flown to indicate the absence of a ship's commanding officer, admiral, his chief-of-staff, or an officer whose flag is nonetheless flying (a 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

Also accommodation hull.

A ship or hull used as housing, generally when there is a lack of quarters available ashore. An operational ship can be used, but more commonly a hull modified for accommodation is used.
Act of Pardon or Act of Grace
A letter from a state or power authorising action by a privateer. See also letter of marque.
action stations
See battle stations.
admiral
A senior naval officer of flag rank. In ascending order of seniority: in the Royal Navy: rear admiral, vice admiral, admiral and (until about 2001, when all British five-star ranks were discontinued) admiral of the fleet; in the U.S. Navy rear admiral (lower half), rear admiral, vice admiral, admiral, and fleet admiral. The term is derived from the Arabic 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.  Another name for admiralty law.
admiralty law
The body of law that deals with maritime cases. In the UK, it is administered by the Admiralty Court, a special court within the Queen's Bench Division of the High Court of Justice. The Admiralty Court is now in the Rolls Building.
adrift
1.  Afloat and unattached in any way to the shore or seabed, but not under way. When referring to a vessel, it implies that the vessel is not under control and therefore goes where the wind and current take her ("loose from moorings" or "out of place").
2.  Any gear not fastened down or put away properly.
3.  Any person or thing that is misplaced or missing. When applied to a member of the navy or marine corps, such a person is "absent without leave" (AWOL) or, in US Navy and US Marine Corps terminology, is guilty of an "unauthorized absence" (UA). [9]
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 that 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 fore or front of a vessel.
2.  In front of a vessel.
aft
1.  Toward the stern or rear of a vessel. [2]
2.  The portion of a vessel behind the middle area of the vessel.
afterbrow
On larger ships, a secondary gangway rigged in the area aft of midship. On some military vessels, such as US naval vessels, enlisted personnel below E-7 board the ship at the afterbrow; officers and CPO/ SCPO/ MCPO board the ship at the brow. [10]
aftercastle

Also sterncastle.

A stern structure behind the mizzenmast and above the transom on large sailing ships, much larger but less common than a forecastle. The aftercastle houses the captain′s cabin and sometimes other cabins and is topped by the poop deck.
afternoon watch
The 1200–1600 watch.
aground
Resting on or touching the ground or bottom (either unintentionally or deliberately, such as in a drying harbour), rather than afloat.
ahead
Forward of the bow.
ahoy
A cry to draw attention. Used to hail a boat or a ship, e.g. "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)
1.  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.
2.  Any sort of marker that aids a traveler in navigation, especially with regard to nautical or aviation travel. Such aids commonly include lighthouses, buoys, fog signals, and day beacons.
aircraft carrier
A warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Frequently shortened to carrier. Since 1918, the term generally has been limited to a warship with an extensive flight deck designed to operate conventional fixed-wing aircraft. In United States Navy slang, also called a flat top or a bird farm.
alee
1.  On the lee side of a ship.
2.  To leeward.
all hands
A ship's entire company, including 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. [9]
allision
The impact of a stationary object (not submerged), such as a bridge abutment or dolphin, pier or wharf, or another vessel made fast to a pier or wharf. More than incidental contact is required. The vessel is said to "allide" with the fixed object and is considered at fault. Contrast collision.
aloft
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 (e.g. "Put your rudder amidships"). Compare midships.
ammunition ship
A naval auxiliary ship specifically configured to carry ammunition, usually for naval ships and aircraft.
anchor
1.  Any object designed to prevent or slow the drift of a ship, attached to the ship by a line or chain; usually a metal, hook or plough-like object designed to grip the solid seabed under the body of water. See also sea anchor.
2.  To deploy an anchor (e.g. "she anchored offshore").
anchor ball
A 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 the position of the anchor on bottom.
anchor chain

Also anchor cable.

A chain connecting a ship to an anchor.
anchor detail
A 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
A white light displayed by a ship to indicate that it is at anchor. Two such lights are displayed by a ship over 150 feet (46 m) in length.
anchor rode

Also simply rode.

The anchor line, rope or cable connecting the anchor chain to the vessel.
anchor sentinel

Also kellet.

A separate weight on a separate line that 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.
anchor watch
The crewmen assigned to take care of a ship while it is anchored or moored, and 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.
anchor winch
A horizontal capstan in the bow used for weighing anchor. [2]
anchorage
Any place suitable for a ship to anchor, often an area of a port or harbor.
anchor's aweigh
Said of an anchor to indicate that it is just clear of the bottom and that the ship is therefore no longer anchored.
Andrew
Traditional lower-deck slang term for the Royal Navy.
anemometer
An instrument to measure wind speed.
aneroid barometer
An instrument to measure air pressure. Used to predict changes in weather.
angle on the bow
A naval submariner's term for the angle between a target's course and the line of sight to the submarine. It is expressed as port or starboard, so never exceeds 180 degrees. This is one of the figures entered into the Torpedo Data Computer that makes all the calculations necessary for a torpedo attack on the target. Not to be confused with doubling the angle on the bow
answer
The expected response of a vessel to control mechanisms, such as a turn "answering" to the wheel and rudder. "She won't answer" might be the report from a helmsman when turning the wheel under a pilot's order fails to produce the expected change of direction.
anti-rolling tanks
A pair of fluid-filled tanks mounted on opposite sides of a ship below the waterline. The tanks are cross-linked by piping or ducts to allow water to flow between them and at the top by vents or air pipes. The piping is sized so that as the fluid flows from side to side it damps the amount of roll.
anti-submarine net

Also anti-submarine boom.

A heavy underwater net attached to a boom placed so as to protect a harbor, anchorage, or strait from penetration by submerged submarines.
apeak
More or less vertical. Having the anchor rode or chain as nearly vertical as possible without freeing the anchor. [citation needed]
aport
Toward the port side of a vessel.
apron
Piece of wood fitted to the after side of the stem post and fore side of the stern post of a clinker built boat, where the planking is secured. [11]
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
A plank along the stern where the name of a ship is commonly painted. [12]
armament
A ship's complement of weapons.
Articles of War
Regulations governing the military and naval forces of the UK and US; read to every ship's company on commissioning and at specified intervals during the commission.
as the crow flies
As measured by a straight line between two points (which might cross land), in the way that a crow or other bird would be capable of traveling rather than a ship, which must go around land. See also great circle.
ASDIC
Purportedly an acronym for Allied Submarine Devices Investigation Committee. A type of SONAR used by the Allies for detecting submarines during the First and Second World Wars. The term has been generically applied to equipment for "under-water supersonic echo-ranging equipment" of submarines and other vessels. [13]
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).
assembly station
See muster station.
astarboard
Toward the starboard side of a vessel.
astern
1.  Toward the stern or rear of a vessel.
2.  Behind a vessel.
astern gear
The gear or gears that, 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. See harbor of refuge.
ASW
An acronym for anti-submarine warfare.
athwart
athwartships
At right angles to the fore and aft or centerline of a ship.
auxiliary ship

Also simply 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. [9] Compare Ya basta.
aviso

Formerly also adviso.

A kind of dispatch boat or advice boat. Survives particularly in the French Navy. They are considered equivalent to modern sloops.
awash
So low in the water that the water is constantly washing across the surface.
aweigh
The position of an anchor that is just clear of making contact with 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
( /ˌ ˈ/) A reply to an order or command to indicate that it, firstly, is heard; and, secondly, is understood and will be carried out (e.g. "Aye, aye, sir" to officers). Also the proper reply from a hailed boat, to indicate that an officer is on board.
azimuth circle
An instrument used to take the bearings of celestial objects.
azimuth compass
An instrument employed for ascertaining the 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

B & R rig
A style of standing rigging used on sailboats that lacks a backstay. The mast is said to be supported like a "tripod", with swept-back spreaders and a forestay. Used widely on Hunter brand sailboats, among others. Designed and named by Lars Bergstrom and Sven Ridder. [citation needed]
back
1.  To make a sail fill with wind on the opposite side normally used for sailing forward. A fore and aft headsail is backed by either not moving the sail across when tacking, or by hauling it to windward with the weather sheet. A square sail is backed by hauling the yards round with the braces. The sail is then aback.
2.  (With oars) to push against the water with the oar in the opposite direction than normally used for moving the boat forward. This is used to slow the speed of the boat, or to move astern when manoeuvring.
back and fill
A method of keeping a square-rigged vessel under control while drifting with the tide along a narrow channel. The ship lies broadside to the current, with the main topsail backed and the fore and mizzen topsail full: essentially a hove-to position. Selective backing and filling of these sails moves the ship ahead or astern, so allowing it to be kept in the best part of the channel. A jib and the spanker are used to help balance the sail plan. This method cannot be used if the wind is going in the same direction and at the same speed as the tide. [1] :199-202
backstay
A stay or cable, reaching from the mast heads, of the topmast, the topgallant-mast the royal-mast, the skysail-mast to the ships side abaft the lower rigging; used to support the mast. [14]
back wash
Water forced astern by the action of the propeller. Also, the receding of waves.
baggywrinkle
A soft covering for standing rigging (such as shrouds and stays) that prevents sail chafing.
bailer
Any device for removing water that has entered a vessel.
baldie
A type of Scottish sailboat introduced in 1860, used for fishing. A baldie is carvel-built, with her mast far forward and rigged with a lug sail and sometimes a jib. Some historians believe "Baldie" is a contraction of "Garibaldi", a reference to the Italian general and nationalist Giuseppe Garibaldi, whose name was a household word at the time the baldie was introduced.
ballast
Heavy material that is placed in a position low in the hull to provide stability. It can be moveable material, such as gravel or stones, permanently or semi-permanently installed, or integral to the hull, such as the (typically) lead or cast-iron ballast keel of a sailing yacht. See also in ballast.
ballast tank
A device used on ships, 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
A traditional Royal Navy term for a day or less of rest and relaxation.
bar
Any large mass of sand or earth formed and raised above the water surface by the surge of the sea. Bars are mostly found at the entrances of great rivers or havens, and often render navigation extremely dangerous, but confer tranquility in the inshore waters by acting as a barrier against strong waves. See also touch and go and grounding.
bar pilot
A navigator who guides a ship over dangerous sandbars at the mouths of rivers and bays.
barber hauler
A technique of temporarily rigging a sailboat lazy sheet so as to allow the boat to sail closer to the wind; i.e. using the lazy jib sheet to pull the jib closer to the mid line, allowing a point of sail that would otherwise not be achievable. [citation needed]
barbette
1.  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, particularly on ships built during the second half of the 19th century.
2.  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, particularly on ships built after the late 19th century.
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 and 18th centuries. 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.
bare poles
Sailing without any canvas raised, usually in a strong wind.
barge
1.  A towed or self-propelled flat-bottomed boat, built mainly for river, canal or 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.
barge slip
A specialized docking facility designed to receive a barge or car float that is used to carry wheeled vehicles across a body of water.
bark
An alternate spelling of barque.
barkentine
An alternate spelling of barquentine.
barque

Also spelled bark.

A sailing vessel of three or more masts, with all masts square-rigged except the sternmost, which is fore-and-aft-rigged.
barquentine

Also spelled barkentine.

A sailing vessel with three or more masts, with all masts fore-and-aft-rigged except the foremast, which is square-rigged.
barrack ship
A ship or craft designed to function as a floating barracks for housing military personnel.
barratry
In admiralty law, an act of gross misconduct against a shipowner or a ship's demise charterer by a ship′s master or crew that damages the ship or its cargo. Acts of barratry can include desertion, illegal scuttling, theft of the ship or cargo and committing any actions that may not be in the shipowner's or demise charterer′s best interests.
barometer
An instrument for measuring air pressure. Used in weather forecasting.
barrelman
A sailor stationed in the crow's nest.
batten
1.  A stiff strip used to support the roach of a sail, increasing the sail area.
2.  Any thin strip of material (wood, plastic, etc.).
batten down the hatches
To prepare for inclement weather by securing the closed cargo hatch covers with wooden battens so as to prevent water from entering from any angle.
battle stations

Also general quarters or action stations.

1.  An announcement made aboard a naval warship to signal the crew to prepare for battle, imminent damage, or any other emergency (such as a fire).
2.  Specific positions in a naval warship to which one or more crew members are assigned when battle stations is called.
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 a 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 and designed to fight other battleships in a line of battle. It was the successor to the ship-of-the-line used during the Age of Sail.
beaching
Deliberately running a vessel aground so as to load or unload it (as with landing craft), or sometimes to prevent a damaged vessel from sinking or to facilitate repairs below the waterline.
beacon
A lighted or unlighted fixed aid to navigation attached directly to the Earth's surface. Examples include lighthouses and daybeacons.
beakhead
1.  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 centuries, usually ornate, which was 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 its widest point, or a point alongside the ship at the midpoint of its length.
beam ends
The sides of a ship. To describe a ship as "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. This is normally the fastest point of sail for a fore-and-aft-rigged vessel.
beam sea
A sea in which waves are moving perpendicular to a vessel's course. [15]
beam wind
A wind blowing perpendicular to a vessel's course.
bear
A large, squared-off stone used with sand for scraping wooden decks clean.
bear down

Also bear away.

To turn or steer a vessel away from the wind, often with reference to a transit. [2]
bear up
To turn or steer a vessel into the wind. [2]
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.
beat to quarters
Prepare for battle (in reference to beating a drum to signal the need for battle preparation).
beating or beat to
Sailing as close as possible towards the wind (perhaps only about 60°) in a zig-zag course so as to attain an upwind direction into which it is otherwise impossible to sail directly. See also tacking.
Beaufort scale
A scale describing wind speed, devised by Admiral Sir Francis Beaufort in 1808, in which winds are graded by the effects of their force on the surface of the sea or on a vessel (originally, the amount of sail that a fully rigged frigate could carry).
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 a lack of wind, said of a sailing vessel; resigned merely to drift with the current rather to move by controlled management of sails.
becket
A short piece of line usually spliced into a circle or with an eye on either end.
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 were typically quartered in the sternmost areas of the ship (near the quarterdeck), while officer-trainees lived between the two ends of the ship and become known as "midshipmen". Crew members who started out as seamen and then became midshipmen, and later, officers, were said to have gone from "one end of the ship to the other". See also 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 pin
A short movable bar of iron or hard wood to which running rigging may be secured, or "belayed". Belaying pins are inserted in holes in a pin-rail. [14]
bell
See ship's bell.
bell rope
A short length of line made fast to the clapper of the ship's bell.
bell buoy
A type of buoy with a large bell and hanging hammers that sound by wave action. [16]
below
On or into a lower deck.
below decks
In or into any of the spaces below the main deck of a vessel.
belt armor
A layer of heavy metal armor plated onto or within the outer hull of a warship, 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
1.  A knot used to join two ropes or lines. See also hitch. [2]
2.  To attach a rope to an object. [2]
3.  Fastening a sail to a yard. [17]
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 a single mast setting a Bermuda rig mainsail and a single headsail. The Bermuda sloop is a very common type of modern sailing yacht.
berth
1.  A location in a port or harbor used specifically for mooring vessels while not at sea.
2.  A safe margin of distance to be kept by a vessel from another vessel or from an obstruction, hence the phrase "to give a wide berth". [18]
3.  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 for anchoring a vessel.
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
1.  A loop in a 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]
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
1.  The part of the hull that the ship rests on if it takes the ground; the outer end of the floors. The "turn of the bilge" is the part of the hull that changes from the (approximately) vertical sides of the hull to the more horizontal bottom of the ship. [19]
2.  (Usually in the plural: "bilges") The compartment at the bottom of the hull of a ship or boat where water collects and must be pumped out of the vessel; the space between the bottom hull planking and the ceiling of the hold. [2]
3.  To damage the hull in the area of the bilge, usually by grounding or hitting an obstruction.
bilge keel
One of 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 such that the anchor cable runs under the hull.
bill
The extremity of the arm of an anchor; the point of or beyond the fluke.
billethead
1.  On smaller vessels, a smaller, non-figural carving, most often a curl of foliage, might be substituted for a figurehead.
2.  A round piece of timber at the bow or stern of a whaleboat, around which the harpoon line is run out when the whale darts off.
Bimini top
An 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, usually near the helm, permitting ready reference by the helmsman.
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.
bird farm
United States Navy slang for an aircraft carrier.
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 a vessel has acquired steerageway.
bitt
1.  A post or pair of posts mounted on the ship's bow for fastening ropes or cables.
2.  A strong vertical timber or iron fastened through the deck beams that is used for securing ropes or hawsers. [2]
bitt heads
The tops of two massive timbers that support the windlass on a sailing barge. [2]
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. crew members who work in the vessel 's engine room, fire room and/or boiler room, so called because they would typically be covered in coal dust during the days of coal-fired steamships.
blinker
A search light, used for signalling by code. Usually fitted with a spring controlled shutter.
block
A pulley with one or more sheaves or grooves over which a line is roved. It can be used to change the direction of the line, or in pairs used to form a tackle. [2]
block, fiddle
A block with two sheaves in the same plane, one being smaller than the other, giving the block a somewhat violin appearance.
block, snatch
A single sheave block with one end of the frame hinged and able to be opened, so as to admit a line other than by forcing an end through the opening.
blockship
A vessel sunk deliberately to block a waterway to prevent the waterway′s use by an enemy.
Blue Ensign
A flag flown as an ensign by certain British ships. Prior to 1864, ships of the Royal Navy′s Blue Squadron flew it; since the reorganisation of the Royal Navy in 1864 eliminated its naval use, it has been flown instead by British merchant vessels whose officers and crew include a certain prescribed number (which has varied over the years) of retired Royal Navy or Royal Naval Reserve personnel or are commanded by an officer of the Royal Naval Reserve in possession of a government warrant; Royal Research Ships by warrant, regardless of their manning by naval, naval reserve and Merchant Navy personnel; or British-registered yachts belonging to members of certain yacht clubs, although yachts were prohibited from flying the Blue Ensign during World War I and World War II.
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.
board
1.  To step onto, climb onto or otherwise enter a vessel.
2.  The side of a vessel.
3.  The distance a sailing vessel runs between tacks when working to windward.
boat
1.  Any 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 blunt tip and a hook on the end, sometimes with a ring on its opposite end to which a line may be attached. Typically used to assist in docking and undocking a boat, with its hook used to pull a boat towards a dock and the blunt end to push it away from a dock, as well as to reach into the water to help people catch buoys or other floating objects or to reach people in the water.
boat keeper
A boatkeeper was a sailor that knew the harbor thoroughly and was able to act as a pilot. He was in command after the last pilot had left to board a ship and brought the pilot boat back to harbor. He was required to know how to use a sextant as he could be 300 miles from port.
boathouse
A building especially designed for the storage of boats, typically located on open water such as a lake or river. Boathouses are normally used to store smaller sports or leisure craft, often rowing boats but sometimes craft such as punts or small motor boats.
boatsteerer
A member of the crew of a 19th-century whaling ship responsible for pulling the forward oar of a whaleboat and for harpooning whales.
boatswain

Also bosun.

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.
bob or bobfly
A pennant or flag bearing the owner's colors and mounted on the topsail trunk. [2]
bobstay
A stay that holds the bowsprit downwards, counteracting the effect of the forestay and the lift of sails. Usually made of wire or chain to eliminate stretching. [2]
body plan
In shipbuilding, an end elevation showing the contour of the sides of a ship at certain points of her length.
boiler room
See fire room.
bolt rope
A rope, sewn on to reinforce the edges of a sail. [2]
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.
bomb vessel

Also bomb, bombard, bombarde, bomb ketch or bomb ship.

A type of specialized naval wooden sailing vessel of the late 17th through mid-19th centuries designed for bombarding fixed positions on land, armed for this purpose with mortars mounted forward near the bow.
bombard

Also spelled bombarde.

1.  A small, two-masted vessel common in the Mediterranean in the 18th and 19th centuries, similar in design to an English ketch.
2.  An alternative name used in the 18th and 19th centuries for a bomb vessel.
Bombay runner
A large cockroach.
bonded jacky
A type of tobacco or sweet cake.
bone in her teeth
A phrase describing the appearance of vessel throwing up a prominent bow wave while travelling at high speed. From a vantage point in front of the vessel, the wave rising in either side of the bow evokes the image of a dog carrying a bone in its mouth, and the vessel is said to have a bone in her teeth.
bonnet
An additional strip of canvas laced to the foot of a sail to increase its area in light winds. [20] :359
booby
A type of bird that has little fear and therefore is particularly easy to catch.
booby hatch
A raised framework or hood like covering over a small hatchway on a ship.
boom
1.  A floating barrier to control navigation into and out of rivers and harbors.
2.  A spar attached to the foot of a fore-and-aft sail. [14]
3.  A spar to extend the foot of gaffsail, trysail or jib. [14]
3.  A spar to extend the yards of square-rigged masts to allow the carrying of studding sails. [14]
boom defence vessel
An alternative term for a net laying ship.
boomer
Slang term in the US Navy for a ballistic missile submarine.
boom crutch
A frame in which the boom rests when the sail is not hoisted.
boom gallows
A raised crossmember that supports a boom when the sail is lowered (and which obviates the need for a topping lift).
boomie or booms'l rig
A ketch-rigged barge with gaff (instead of spritsail) and boom on main and mizzen. Booms'l rig could also refer to cutter-rigged early barges. [2]
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 or boomkin.
booms
Masts or yards, lying on board in reserve.
boot-top
The area on the ship's hull along the waterline, usually painted a contrasting color.
bore, as in bore up or bore away
To assume a position to engage, or disengage, the enemy ships.
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. [2]
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).
bow chaser
See chase gun.
bowline
1.  A type of knot producing a strong loop of a fixed size, topologically similar to a sheet bend. [2]
2.  A rope attached to the side of a sail to pull it towards the bow (for keeping the windward edge of the sail steady). [2]
2.  A rope attached to the foresail to hold it aback when tacking. [2]
bowman
The person, in a team or among oarsmen, positioned nearest the bow.
bowpicker
A gillnetter that fishes by deploying a gillnet from her bow.
bowse
To pull or hoist.
bow sea
Seas approaching a vessel from between 15° and 75° to port or starboard. [15]
bows on
Said of a vessel directly approaching an observer, e.g., "The ship approached us bows on."
bowsprit
A spar projecting from the bow that is used as an anchor for the forestay and other rigging. On a barge it may be pivoted so it may be steeved up in harbor. [2]
bows under
Said of a vessel shipping water over her bow, e.g., "The ship was bows under during the storm."
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.
bow visor
A feature of some ships, particularly ferries and roll-on/roll-off ships, that allows a vessel's bow to articulate up and down to provide access to her cargo ramp and storage deck near the waterline.
bow wave
The wave created on either side of a vessel's bow as she moves through the water.
boxing the compass
To state all 32 points of the compass, starting at north and proceeding clockwise. Sometimes applied to a wind that is constantly shifting.
boy seaman
A young sailor, still in training.
brace
On square rigged ships, a line attached to the yard to turn it, for trimming the sail.
brace abox
To bring the foreyards flat aback to stop the ship.
brail
1.  To furl or truss a sail by pulling it in towards the mast. "To brail up" or "to hale up the brails" is to stow the sails. [2]
2.  A small line used to haul the edges or corners of sails up or in before furling them. In a ship rig, brails are most often found on the mizzen sail.
brail net
A type of net incorporating brail lines on a small fishing net on a boat.
brailer
A device consisting of a net of small-mesh webbing attached to a frame, used aboard fishing vessels for unloading large quantities of fish.
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". Apocryphally, it is often claimed that a brass monkey was a frame used to hold cannon balls, and low temperature would cause the frame to contract to a greater degree than the iron balls and thus allow them to roll off. The probable actual etymology is given here
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.
breachway
1.  The shore along a channel.
2.  The whole area around the place where a channel meets the ocean.
break bulk cargo

Also 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.
breaker
1.  A shallow portion of a reef over which waves break.
2.  A breaking wave that breaks into foam against the shore, a shoal, a rock or a reef. Sailors use breakers to warn themselves of their vessel's proximity to an underwater hazard to navigation or, at night or during periods of poor visibility, of their vessel's proximity to shore.
3.  A ship breaker, often used in the plural, e.g. "The old ship went to the breakers".
4.  A small cask of liquid kept permanently in a ship's boat in case of shipwreck.
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.
breastrope
A mooring rope fastened anywhere on a ship's side that goes directly to the quay, so that it is roughly at right angles to both. [21] :40
bridge
A structure above the weather deck, extending the full width of the vessel, which houses a command center, itself called by association the bridge.
bridge wing
A narrow walkway extending outward from both sides of a pilothouse to the full width of a ship or slightly beyond, to allow bridge personnel a full view to aid in the maneuvering of the ship, such as when docking.
brig
1.  (historically) A vessel with two square-rigged masts.
2.  (in the US) An interior area of a ship that is used to detain prisoners (possibly prisoners-of-war, in wartime) or 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 that 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 on a boat or ship. [21]
bring to
To cause a ship to be stationary by arranging the sails.
broach
When a sailing or power vessel loses directional control when travelling with a following sea. The vessel turns sideways to the wind and waves and in more serious cases may capsize or pitchpole. Advice on dealing with heavy weather includes various strategies for avoiding this happening. [22] [23]
broad
Wide 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.
Broad Fourteens
An area of the southern North Sea which is fairly consistently 14 fathoms (84 feet; 26 metres) deep. On a nautical chart with depths indicated in fathoms, it appears as a broad area with many "14" notations.
broadhorn
An alternate term for a flatboat.
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 to fire on the same side of a warship.
3.  The simultaneous firing of all the guns on one side of a 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 engagement, or the combined weight of all the shells which a group of ships that have formed a line of battle can collectively fire on the same side.
Brouwer Route
A route used by ships in the 17th century while sailing east from the Cape of Good Hope to the Netherlands East Indies which took advantage of the strong westerly winds in the southern Indian Ocean known as the " Roaring Forties" to speed the trip but required ships to turn north in the eastern Indian Ocean to reach the East Indies. With no accurate means of determining longitude at the time, ships which missed the northward turn ran the risk of being wrecked on the west coast of Australia.
brow
See gangplank.
buffer
The chief bosun's mate (in the Royal Navy), responsible for discipline.
bug shoe
A length of hardened material placed on a skeg to protect the skeg from damage by shipworms. [24]
bugeye
A type of sailboat developed in the Chesapeake Bay by the early 1880s for oyster dredging, superseded as the chief oystering boat in the bay by the skipjack at the end of the 19th century.
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

Also bulward.

The extension of a ship's side above the level of the weather deck.
Bulwark (or bulward)
bull ensign

Also boot ensign or George ensign.

The senior ensign of a US Navy command (i.e. a ship, squadron or shore activity). The bull ensign assumes additional responsibilities beyond those of other ensigns, such as teaching less-experienced ensigns about life at sea, planning and coordinating wardroom social activities, making sure that the officers' mess runs smoothly, and serving as an officer for Navy-related social organizations. The bull ensign also serves as the focal point for the unit's expression of spirit and pride.
bullseye
A glass window above the captain's cabin to allow viewing of the sails above deck.
bumboat
A private boat selling goods.
bumpkin or boomkin
1.  A spar, similar to a bowsprit, but which projects from the stern rather than the bow. May be used to attach the backstay or mizzen sheets [14]
2.  An iron bar projecting outboard from a ship's side to which the lower and topsail brace blocks are sometimes hooked.
bunk
A built in bed on board ship.
bunker
A container for storing coal or fuel oil for a ship 's engine.
bunker fuel or bunkers
Fuel oil for a ship.
bunt
1.  Middle cloths of a square sail. [25]
2.  Centre of a furled square sail. [25]
bunt-gasket
Canvas apron used to fasten the bunt of a square sail to the yard when furled. [25]
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 leading from the foot of a square sail over a block at the head and down to the deck; and used to haul it up to the yard when furling. [25]
buoy
A floating object, usually anchored at a given position and fulfilling one of a number of uses, recognised by a defined shape and color for each, including aids to navigation, warnings of danger such as submerged wrecks or divers, or for attaching mooring lines, lobster pots, etc.
buoyed up
Lifted by a buoy, especially a cable that has been lifted to prevent it from trailing on the bottom.
burthen
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 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.
Burgoo
A dish of ships biscuit crumbs and minced salt pork, usually a meal of last resort for officers when other food stores are exhausted.
butt
Where the butt of one plank joins with the butt of another.
by and large
By means into the wind, while large means with the wind. "By and large" is therefore used to indicate all possible situations, e.g. "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, especially one used as living quarters.
cabin boy
An attendant to passengers and crew, often a young man.
cable
1.  A large rope.
2.  A cable length.
cable length
A measure of length or distance equivalent to 110 nautical mile (608 feet; 185 metres) in the United Kingdom and 100 fathoms (600 feet; 183 metres) in the United States; other countries use different equivalents. Sometimes called simply a cable.
caboose
A small ship's kitchen, or galley on deck.
cabotage
The transport of goods or passengers between two points within the same country, alongside coastal waters, by a vessel or an aircraft registered in another country.
cage mast
Alternative term for a lattice mast.
camels
Loaded vessels lashed tightly, one on each side of another vessel, and then emptied to provide additional buoyancy that reduces the draft of the ship in the middle.
can
A type of navigational buoy, often a vertical drum, but otherwise always square in silhouette, colored red in IALA region A (Europe, Africa, Greenland, and most of Asia and Oceania) 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 such that it is pointed like a bow, rather than squared off as a transom.
canvas
A general term for sails. It may be used as a collective term for all of the sails on a vessel, and the total area of sails aboard her may be expressed as the area of her canvas.
cap
A fitting or band used to connect the head of one mast to the lower portion of the mast above. [25]
Cape Horn fever
A feigned illness a malingerer is pretending to suffer from.
Cape Horn roller

Also graybeard.

A type of large ocean wave commonly encountered in the stormy seas of the Southern Ocean south of South America′s Cape Horn, often exceeding 60 feet (18.3 m) in height. The geography of the Southern Ocean, uninterrupted by continents, creates an endless fetch that is favorable for the propagation of such waves.
cap-stay
A backstay leading from a mast cap to the ship's side. [25]
capital ship
One of a set of ships considered 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, capital ships were generally understood to be ships-of-the-line; during the second half of the 19th century and the 20th century, they were typically battleships and battlecruisers; and since the mid-20th century, the term may also include aircraft carriers and ballistic missile submarines.
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.
capstan
A large winch with a vertical axis used to wind in anchors or other heavy objects, and sometimes to administer flogging over. 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.
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 captain is called her master.
2.  A naval officer with a rank between commander and commodore.
3.  In the US Navy, US 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 US Army, US Marine Corps, or US 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 US Coast Guard officer, usually a captain, responsible for enforcement of safety, security, and marine environmental protection regulations in a commercial port.
captain's daughter
Another name for 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 carrier
A cargo ship specially designed or fitted to carry large numbers of automobiles. Modern pure car carriers have a fully enclosed, box-like superstructure that extends along the entire length and across the entire breadth of the ship, enclosing the automobiles. The similar pure car/truck carrier can also accommodate trucks.
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

Also heaving down.

Tilting a ship on its side, usually when beached, to clean or repair the hull below the waterline.
cargo liner

Also passenger-cargo ship or passenger-cargoman.

A type of merchant ship that became common just after the middle of the 19th century, configured primarily for the transportation of general cargo but also for the transportation of at least some passengers. Almost completely replaced by more specialized cargo ships during the second half of the 20th century.
cargo ship
Any 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 centuries.
carrier
An aircraft carrier.
carronade
A short, smoothbore, cast-iron naval cannon, used from the 1770s to the 1850s as a powerful, short-range, anti-ship and anti-crew weapon.
cartel
A ship employed on humanitarian voyages, in particular to carry communications or prisoners between belligerents during wartime. A cartel flies distinctive flags, including a flag of truce, traditionally is unarmed except for a lone signaling gun, and under international law is not subject to seizure or capture during her outbound and return voyages as long as she engages in no warlike acts.
carvel-built
A method of constructing a wooden hull by fixing planks on the frames edge-to-edge, so giving a smooth hull surface, as opposed to clinker-built. [20] :359
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.
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 often kept in a baize bag, a possible origin for the term "cat out of the bag". [26] "Not enough room to swing a cat" also derives from this.
catamaran
Any 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.
cat's paws
Light variable winds on calm waters producing scattered areas of small waves.
caulk
To create a watertight seal between structures. In traditional carvel construction this involved hammering oakum (recycled rope fibres) or caulking cotton into the slightly tapered fine gaps between the hull or deck planks and, in older methods, covering with tar. The expansion of the fibres in water tightens up the hull, making it less prone to racking movement, as well as making the joint watertight. [19]
celestial navigation
Navigation by the position of celestial objects, including the stars, Sun, and Moon, using tools aboard ship such as a sextant, chronometer, and compass, and published tables of the position of celestial objects. Celestial navigation was the primary method of navigation until the development of electronic global positioning systems such as LORAN and GPS.
ceiling
Planking attached to the inside of the frames or floors of a wooden hull, usually to separate the cargo from the hull planking itself. The ceiling has different names in different places: limber boards, spirketting, quickwork. The lower part of the ceiling is, confusingly to a landsman, what you are standing on at the bottom of the hold of a wooden ship. [20] :359
center of effort

Also center of pressure.

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.
center of lateral resistance
The point of origin of net hydrodynamic resistance on the submerged structure of a boat, especially a sailboat. This is the pivot point the boat turns about when unbalanced external forces are applied, similar to the center of gravity. On a balanced sailboat, the center of effort should align vertically with the center of lateral resistance. If this is not the case the boat will be unbalanced and exhibit either lee helm or weather helm and will be difficult to control.
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 said to be "on the centerline".
centerboard
A board or plate lowered through the hull of a sailing vessel on the centerline to resist leeway. Very common in a dinghy, but also found in some larger boats.
chafing
Wear on a 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, puddening. [25]
chain locker
A space in the forward part of a 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
Cannonballs linked with short lengths of chain, used to damage rigging and masts.
Chain plates
Iron bars bolded to a ships side to which the dead-eyes or rigging screws of the lower figging and the back-stays are bolted. [25]
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. [25]
chains
Small platforms built into the sides of a ship to spread the shrouds to a more advantageous angle. Also used as a platform for manual depth sounding.
chalupa
1.  A small boat that functions as a shallop ( q.v.), water taxi ( q.v.), or gondola ( q.v.).
2.  In Portuguese, a small boat used for cabotage, propelled by either oars or sails. Those equipped with sails have a single mast.
3.  A type of whaling boat used by the Basques in the mid-16th century in what is now Newfoundland and Labrador.
channel fever
1.  The impatient excitement in a ship's crew as the end of a voyage becomes imminent. Characteristics include crew members working harder to get the ship sailing faster, off-watch personnel being on deck to keep track of progress, and everyone being packed and in their shore-going clothes (ready to be paid off) as the vessel arrives alongside. [27]
2.  (obsolete usage) A crew member avoiding duties with a feigned illness, usually after leaving port.
Charley Noble
The metal stovepipe chimney from a cook shack on the deck of a ship or from a stove in a galley.
chartered ship
A term used by the British East India Company from the seventeenth to the nineteenth century for a merchant ships it chartered to make a single, often only one-way, voyage it between England (later the United Kingdom) and ports east of the Cape of Good Hope, a trade over which the company held a strict monopoly. A "charter ship" during its single voyage was employed much in the same way as what the company called an "extra ship" ( q.v.), but the company usually hired a "chartered ships" on special terms and for much shorter period than an "extra ships." [28]
charthouse
A compartment, especially in the Royal Navy, from which the ship was navigated.
chartplotter
An electronic instrument that places the position of the ship (from a GPS receiver) onto a digital nautical chart displayed on a monitor, thereby replacing all manual navigation functions. Chartplotters also display information collected from all shipboard electronic instruments and often directly control autopilots.
chase gun

Also chase piece or chaser.

A cannon pointing forward or aft, often of longer range than other guns. Those on the bow ( bow chasers) were used to fire upon a ship ahead, while those on the rear ( stern chasers) 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.  Flat plates of iron or wood bolted to the mast-head to form angle supports for the cross-trees. [25]
3.  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. [2] Soft chine is when the two sides join at a shallow angle, and hard chine is when they join at a steep angle.
chock
A hole or ring attached to the hull to guide a line via that point; an opening in a ship's bulwark, normally oval in shape, designed to allow mooring lines to be fastened to cleats or bits mounted to the ship's deck. See also Panama chock and Dutchman's chock.
chock-a-block
Rigging blocks that are so tight against one another that they cannot be further tightened. [2]
chronometer
A timekeeping device accurate enough to be used to determine longitude by means of celestial navigation.
cigarette boat
See go-fast boat.
citadel
A fortified safe room on a vessel to take shelter in the event of pirate attack. Previously, a fortified room to protect ammunition and machinery from damage.
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. Sometimes used informally to refer to a group of non-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 a 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. [2]
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
One of the lower corners of a square sail or the corner of a triangular sail at the end of the boom. [2]
clewlines
Used to truss up the clews, the lower corners of square sails. Used to reduce and stow a barge's topsail. [2]
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. Contrast carvel-built.
Clipper
A sailing vessel designed primarily for speed. While the square rigged clipper ships of the middle of the 19th century are well known, others, such as Baltimore Clippers and opium clippers could be rigged differently, often as schooners, and a small number of 19th century clippers were built as barques.
close aboard
Near a ship.
close-hauled
Of a vessel beating as close to the wind direction as possible.
clove hitch
A bend used to attach a rope to a post or bollard. Also used to finish tying off the foresail. [2]
club hauling
A maneuver by which a ship drops one of its anchors at high speed in order 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

Also simply trimmer.

A person responsible for ensuring that a coal-fired vessel remains in "trim" (evenly balanced) as coal is consumed on a voyage.
coaling
Loading coal for use as fuel aboard a steamship. A time-consuming, laborious, and dirty process often undertaken by the entire crew, coaling was a necessity from the early days of steam in the 19th century until the early 20th century, when oil supplanted coal as the fuel of choice for steamships.
coaming
The raised edge of a hatch, cockpit, or skylight, designed to help keep out water.
coaster
A coastal trading vessel; a shallow-hulled ship used for trade between locations on the same island or continent.
coble
A type of open traditional fishing boat, with a flat bottom and high bow, which developed on the northeast coast of England.
cockbill
1.  Use of spars, to stow by swinging askew. [2]
2.  When a yard is canted at an angle. [25]
cockpit
A seating area (not to be confused with the deck) 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 centuries.
coign (gunnery)
1.  A wedge used to assist in the aiming of a cannon: An older form of "Quoin"
collier
A bulk cargo ship designed to carry coal, especially such a ship in naval use to supply coal to coal-fired warships.
combat loading
A way of loading a vessel giving military forces embarked aboard her immediate access to weapons, ammunition, and supplies needed when conducting an amphibious landing. In combat loading, cargo is stowed in such a way that unloading of equipment will match up with the personnel that are landing and in the order they land so that they have immediate access to the gear they need for combat as soon as they land. Combat loading gives primary consideration to the ease and sequence with which troops, equipment, and supplies can be unloaded ready for combat, sacrificing the more efficient use of cargo space that ship operators seek when loading a ship for the routine transportation of personnel and cargo.
comber
A long, curving wave breaking on the shore.
come about
1.  To tack.
2.  To change tack.
3.  To manoeuvre 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.  ( rank) Prior to 1997, the title used in the Royal Navy for an officer of the rank of captain who was given temporary command of a squadron. At the end of the deployment of the squadron, or in the presence of an admiral, he would revert to his de facto rank of Ccptain.
2.  ( 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.
3.  ( 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.
4.  ( commodore (yacht club)) An officer of a yacht club.
5.  ( Commodore (Sea Scouts)) A position in the Boy Scouts of America's Sea Scouts program.
communication tube

Also speaking tube or voice tube.

An air-filled tube, usually armored, allowing speech between the conning tower and the below-decks control spaces in a warship.
companionway
A raised and windowed hatchway in a ship's deck, with a ladder leading below and the hooded entrance-hatch to the main cabins.
complement
1.  The number of persons in a ship′s crew, including officers.
2.  A collective term for all of the 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 or mission (e.g. "The task force comprises Ship A, Ship B, and Ship C"). "Comprise" means exhaustive inclusion – there are not any other parts to the task force, and each ship has a permanent squadron existence, independent of the task force.
concrete ship
A vessel constructed of steel and ferrocement (a type of reinforced concrete) rather than of more traditional materials, such as steel, iron, or wood. [29]
conn

Also 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.  An armored 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 that no longer plays a role 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 collision, "constant bearing, decreasing range" has come to mean a problem or an obstacle which is incoming. [30]
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. [31] [32]
corrector
A device used to correct the ship's compass, e.g. by counteracting errors due to the magnetic effects of a steel hull.
corsair
1.  A French privateer, especially one 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 (dinghy)) A class of 16-foot (4.9-metre) 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. In the US Navy, it is referred to as a sloop-of-war.
2.  A lightly armed and armored warship of the 20th and 21st centuries, smaller than a frigate, and capable of trans-oceanic duty.
cotchel
A partial load. [33]
cottonclad
A steam-powered wooden warship protected from enemy fire by bales of cotton lining its sides, most commonly associated with some of the warships employed by the Confederate States of America during the American Civil War (1861–1865).
counter
The part of the stern above the