Glossary of nautical terms (A-L)
This glossary of nautical terms is an alphabetical listing of terms and expressions connected with ships, shipping, seamanship and navigation on water (mostly though not necessarily on the sea). Some remain current, while many date from the 17th to 19th centuries. The word nautical derives from the Latin nauticus, from Greek nautikos, from nautēs: "sailor", from naus: "ship".
Further information on nautical terminology may also be found at Nautical metaphors in English, and additional military terms are listed in the Multiservice tactical brevity code article. Terms used in other fields associated with bodies of water can be found at Glossary of fishery terms, Glossary of underwater diving terminology, Glossary of rowing terms, and Glossary of meteorology.
This glossary is split into two articles:
- terms starting with the letters A to L are at Glossary of nautical terms (A-L)
- terms starting with the letters M to Z are at Glossary of nautical terms (M-Z).
- An acronym for anti-aircraft warfare.
- (of a ) Filled by the wind on the opposite side to the one normally used to move the vessel forward. On a ship, any of the square sails can be braced round to be aback, the purpose of which may be to reduce speed (such as when a is keeping station with others), to heave to, or to assist moving the ship's head through the eye of the wind when . A sudden shift in the wind can also cause a square-rigged vessel to be unintentionally "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 or by tacking without releasing the sheet. It is used to heave to or to assist with tacking. See also back and fill.
- Toward the , 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".
- abandon ship
- An imperative to leave the vessel immediately, usually in the face of some imminent overwhelming danger. It is an order issued by the lifeboats" or life rafts. 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, when destruction or loss of the ship is imminent, and is customarily followed by a command to "man the
- On the beam; a relative bearing at right angles to the ship's keel; e.g. describing an object located at a bearing of 90 degrees (starboard) or 270 degrees (port) as measured clockwise from the ship's bow.
- able seaman (AB)
- A merchant seaman qualified to perform all routine duties on a vessel, or a junior rank in some navies.
- On or in a vessel. Synonymous with "on board". See also close aboard.
- To change the course of a ship by . "Ready about" is the order to prepare for tacking.
- above board
- On or above the deck; in plain view; not hiding anything. Pirates would often hide their crews below decks, thereby creating the false impression that an encounter with another ship was a casual matter of chance rather than a planned assault.
- above-water hull
- The section of a vessel's hull above the ; the visible part of a ship. See also .
- absentee pennant
- A special pennant flown to indicate the absence of a ship's commanding officer, admiral, 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
- 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
- A letter from a state or power authorising action by a privateer. See also letter of marque.
- action stations
- See battle stations.
- 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").
- 1. A high naval authority in charge of a state's 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. or a major territorial component. In the
- 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.
- 1. Afloat and unattached in any way to the shore or seabed, but not . When referring to a vessel, it implies that the vessel is not being or able to be controlled and therefore goes where the wind and current take her; a vessel in this condition may also be described as "loose from her moorings" or "out of place".
- 2. Any gear not fastened down or stored 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 said to be "absent without leave" (AWOL) or, in U.S. Navy and U.S. Marine Corps terminology, is guilty of an "unauthorized absence" (UA).
- advance note
- A note for one month's wages issued to a sailor on his signing a .
- See aviso.
- 1. (of a vessel) Floating freely (not aground or sunk). The term may also be used more generally of any floating object or person.
- 2. In service, even if not currently , but not stranded, crewless, in repair, or under construction (e.g. "the company has 10 ships afloat").
- 1. In, on, or toward the fore or front of a vessel.
- 2. In front of a vessel.
- 1. Toward the or rear of a vessel. Contrast fore.
- 2. The portion of a vessel behind the middle area of the vessel.
- On larger ships, a secondary gangway rigged in the area aft of CPO/SCPO/MCPO board the ship at the brow. . On some military vessels, such as U.S. naval vessels, enlisted personnel below E-7 board the ship at the afterbrow; officers and
- A structure behind the and above the 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 .
- afternoon watch
- The 1200–1600 .
- Resting on or touching the ground or land, or the bottom of a body of water (either unintentionally or deliberately, such as in a drying harbour), as opposed to afloat.
- Forward of the bow.
- A cry to draw attention. Used to hail a boat or a ship, e.g. "boat ahoy".
- 1. Lying broadside to the sea.
- 2. To ride out a storm with no sails and helm held to leeward.
- 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 while at sea, thereby 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. In U.S. Navy slang, also called a "flat top" or a "bird farm".
- Structural section of a vessel that joins the hulls of a multihulled vessel together.
- 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 .
- all standing
- Bringing a person or thing up short; i.e. an unforeseen and sudden stop.
- The impact of a moving vessel with 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.
- 1. In the of a sailing ship.
- 2. Above the ship's uppermost solid structure.
- 3. Overhead or high above.
- By the side of a ship or pier.
- A secondary hull or float attached to the primary hull of a vessel for stability, or the hulls of a modern catamaran.
- 1. A position half way along the length of a ship or boat.
- 2. A position half way between the port and starboard sides of a ship or boat, as in "helm amidships", when the rudder is in line with the keel.
- ammunition ship
- A naval auxiliary ship specifically configured to carry ammunition, usually for combatant ships and aircraft.
- 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 .
- 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 to a line attached to the crown of an anchor. The line allows the anchor to be unhooked from an obstruction, such as a rock or another vessel's anchor cable, so preventing raising the anchor in the normal way.
- anchor chain
- 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 aboard the ship for sea; i.e. when it is not deployed. 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
- The anchor line, rope, or cable connecting the anchor chain to the vessel.
- anchor sentinel
- 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 .
- 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.
- 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.
- Traditional lower-deck slang term for the Royal Navy.
- An instrument used to measure wind speed.
- aneroid barometer
- An instrument used to measure air pressure, often with the aim of predicting changes in weather.
- angle of attack
- The angle between the apparent wind and the chord line of the sail.
- 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.
- The expected response of a vessel to control mechanisms, such as a turn "answering" to the and . "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 . 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 .
- anti-submarine net
- A heavy underwater net attached to a boom and placed so as to protect a harbor, anchorage, or strait from penetration by submerged submarines.
- More or less vertical. Having the anchor rode or chain as nearly vertical as possible without freeing the anchor.
- Toward the side of a vessel.
- A piece of wood fitted to the after side of the post and the fore side of the of a clinker-built boat, where the planking is secured.
- 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 .
- A plank along the where the name of a ship is commonly painted.
- A ship's complement of weapons.
- armor belt
- See belt armor.
- Area on a warship for storage of small arms and ammunition.
- Articles of War
- Regulations governing the military and naval forces of the UK and US; read to every 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.
- Purportedly an acronym for Allied Submarine Devices Investigation Committee, and 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.
- 1. On the beach, shore, or land (as opposed to aboard or on board a vessel).
- 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 .
- Toward the side of a vessel.
- 1. Toward the 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.
- An acronym for anti-submarine warfare.
- At right angles to the fore and aft or centerline of a ship.
- auxiliary ship
- 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.
- 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. Compare .
- A kind of dispatch boat or advice boat, surviving particularly in the French Navy. They are considered equivalent to modern .
- So low in the water that the water is constantly washing across the surface.
- 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
- (/ /) 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.
- azimuth thruster
- A steerable drive leg fitted through the bottom of a hull, carrying a propeller. Compare and .
- 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.
- 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 ) 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 vessel under control while drifting with the tide along a narrow channel. The ship lies broadside to the current, with the main 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 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.
- A stay or cable, reaching from the mast heads, of the topmast, the the , the to the ship's side abaft the lower rigging; used to support the mast.
- back wash
- Water forced astern by the action of the . Also, the receding of waves.
- A soft covering for standing rigging (such as shrouds and stays) that reduces sail chafing.
- Any device for removing water that has entered a vessel.
- bail out
- Tacking away from other boats to obtain clear air. Often used for starting situations.
- 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.
- balance rudder
- Actually not a single rudder, but a set of three or four rudders operating together to maneuver a sternwheel steamboat. Placed just forward of the paddlewheels, the effectiveness of the balance rudder is increased by the flow of water generated by the paddles, giving such steamboats a high degree of maneuverability.
- 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 compartment which can be filled or partly filled with water, used on ships, submarines and other submersibles to control buoyancy and stability.
- Baltimore Clipper
- A fast sailing ship – an early form of clipper – built on the Mid-Atlantic seaboard of the United States, especially at Baltimore, Maryland. Popular as in both the United States and the United Kingdom by the late 18th century, Baltimore Clippers usually were two- or brigantines.
- balls to four watch
- U.S. Navy slang for the 0000–0400 watch.
- A large area of elevated sea floor, deep enough to allow navigation.
- A traditional Royal Navy term for a day or less of rest and relaxation.
- Mass of sand or earth raised above the general seabed depth by the motion of water. Bars are often found at the mouth of rivers or entrances to harbours and can make navigation over them extremely dangerous at some states of tide and current flow, but can also confer tranquility in the inshore waters by acting as a barrier to large waves. See also 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.
- 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.
- 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.
- 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.
- An alternate spelling of barque.
- An alternate spelling of barquentine.
- A sailing vessel of three or more masts, with all masts except the sternmost, which is fore-and-aft-rigged.
- A sailing vessel with three or more masts, with all masts fore-and-aft-rigged except the foremast, which is .
- barrack ship
- A ship or craft designed to function as a floating barracks for housing military personnel.
- 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 , theft of the ship or cargo and committing any actions that may not be in the shipowner's or demise charterer′s best interests.
- An instrument for measuring air pressure. Used in weather forecasting.
- A sailor stationed in the crow's nest.
- 1. A stiff strip used to support the of a , 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
- 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.
- 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.
- 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 Age of Sail. used during the
- 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 .
- A lighted or unlighted fixed aid to navigation attached directly to the Earth's surface. Examples include lighthouses and daybeacons.
- 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).
- 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 for a fore-and-aft-rigged vessel.
- beam sea
- A sea in which waves are moving perpendicular to a vessel's course.
- beam wind
- A wind blowing perpendicular to a vessel's course.
- A large, squared-off stone used with sand for scraping wooden decks clean.
- bear down
- To turn or steer a vessel away from the wind, often with reference to a transit.
- bear up
- To turn or steer a vessel into the wind.
- The horizontal direction of a line of sight between two objects on the surface of the Earth. See also absolute bearing and .
- 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 .
- 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).
- To cut off the wind from a sailing vessel, either by the proximity of land or by another vessel.
- 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.
- A short piece of line usually 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 ), 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.
- 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.
- See .
- bell rope
- A short length of line made fast to the clapper of the .
- bell buoy
- A type of buoy with a large bell and hanging hammers that sound by wave action.
- 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 . 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.
- 1. A knot used to join two ropes or lines. See also hitch.
- 2. To attach a rope to an object.
- 3. Fastening a sail to a yard.
- Bermuda rig or Bermudan rig
- A triangular , without any upper , 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.
- 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".
- 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.
- 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. An indentation in a coastline.
- A small European merchant sailing ship with two masts, the lateen-rigged with a trapezoidal , and the foremast carrying the conventional square course and square . Used in the Netherlands for coast and canal traffic and occasionally in the North Sea, but more frequently used in the Mediterranean Sea.
- 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.
- 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.
- 3. To damage the hull in the area of the bilge, usually by grounding or hitting an obstruction.
- 4. To fail an academic course ("bilge") or curriculum ("bilge out").
- 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.
- The extremity of the arm of an anchor; the point of or beyond the fluke.
- 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 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.
- A punitive instrument.
- 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.
- Verb used in reference to a , 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.
- 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.
- bitt heads
- The tops of two massive timbers that support the on a sailing barge.
- 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.
- A search light, used for signaling by code. Usually fitted with a spring controlled shutter.
- A pulley with one or more 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.
- block, fiddle
- A block with two in the same plane, one being smaller than the other, giving the block a somewhat violin appearance.
- block, snatch
- A single 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.
- 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.
- 1. A enlisted person of the Royal Navy, Commonwealth navies, the United States Navy, or the United States Coast Guard. Bluejacket derives from a blue jacket naval enlisted personnel once wore while ashore. In the Royal Navy and Commonwealth navies, the term generally is synonymous with and often includes petty officers and chief petty officers. In the U.S. Navy and U.S. Coast Guard, the term excludes chief petty officers. or
- 2. More loosely, a sailor or enlisted person of any navy.
- Bluejacket's Manual
- A basic handbook for U.S. Navy personnel.
- 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 when working to .
- 1. Any small craft or vessel designed to float on and provide transport over or under water.
- 2. Naval slang for a 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.
- 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.
- A member of the crew of a 19th-century whaling ship responsible for pulling the forward oar of a whaleboat and for harpooning whales.
- A non-commissioned officer responsible for the sails, ropes, rigging and boats on a ship who issues "piped" commands to seamen.
- boatswain's call
- 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
- 1. 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.
- 2. A metal chair used for ship-to-ship personnel transfers at sea while underway.
- boatswain's pipe
- See boatswain's call.
- boatswain's whistle
- See boatswain's call.
- 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 trunk.
- 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.
- body plan
- In shipbuilding, an end elevation showing the contour of the sides of a ship at certain points of her length.
- A power generation system component that produces steam.
- See fireman.
- boiler room
- See fire room.
- bolt rope
- A rope, sewn on to reinforce the edges of a sail.
- 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
- 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.
- 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 a 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.
- An additional strip of canvas laced to the foot of a sail to increase its area in light winds.
- 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.
- 1. A floating barrier to control navigation into and out of rivers and harbors.
- 2. A attached to the foot of a fore-and-aft sail.
- 3. A spar to extend the foot of gaffsail, trysail or jib.
- 3. A spar to extend the yards of masts to allow the carrying of .
- boom defence vessel
- An alternative term for a .
- Slang term in the U.S. Navy for a ballistic missile submarine.
- boom crutch
- A frame in which the boom rests when the is not hoisted.
- boom gallows
- A raised crossmember that supports a boom when the sail is lowered (and which obviates the need for a ).
- boomie or booms'l rig
- A ketch-rigged barge with gaff (instead of ) and boom on main and . Booms'l rig could also refer to cutter-rigged early barges.
- 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.
- See bumpkin or boomkin.
- Masts or yards, lying on board in reserve.
- The area on the ship's hull along the , usually painted a contrasting color.
- bore, as in bore up or bore away
- To assume a position to engage, or disengage, the enemy ships.
- 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.
- A device for adjusting tension in stays, shrouds and similar lines.
- 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.
- Pledging a ship as security in a financial transaction.
- 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.
- 1. A type of knot producing a strong loop of a fixed size, topologically similar to a sheet bend.
- 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. A rope attached to the foresail to hold it aback when .
- The person, in a team or among oarsmen, positioned nearest the bow.
- A gillnetter that fishes by deploying a gillnet from her bow.
- To pull or hoist.
- bow sea
- Seas approaching a vessel from between 15° and 75° to port or starboard.
- bows on
- Said of a vessel directly approaching an observer, e.g., "The ship approached us bows on."
- A 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.
- 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.
- On ships, a line attached to the to turn it, for the .
- brace abox
- To bring the foreyards flat aback to stop the ship.
- 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. 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.
- A device consisting of a net of small-mesh webbing attached to a frame, used aboard fishing vessels for unloading large quantities of fish.
- 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.
- 1. The shore along a channel.
- 2. The whole area around the place where a channel meets the ocean.
- break bulk cargo
- Goods that must be loaded aboard a ship individually and not in intermodal containers or in bulk, carried by a general cargo ship.
- 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 in case of becoming separated from the ship or if used as a lifeboat.
- 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.
- 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.
- 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 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.
- 1. A vessel with two masts.
- 2. (in the US) An interior area of a ship that is used to detain prisoners (possibly prisoners-of-war, in wartime) or , and to punish delinquent crew members. Usually resembles a prison cell with bars and a locked, hinged door.
- brig sloop
- A type of introduced in the 1770s that had two masts like a brig (in contrast to ship sloops of the time, which had three masts).
- A two-masted vessel, on the foremast but fore-and-aft-rigged on the .
- Exposed varnished wood on a boat or ship.
- bring to
- To cause a ship to be stationary by arranging the sails.
- 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 . Advice on dealing with heavy weather includes various strategies for avoiding this happening.
- 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 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.
- An alternate term for a flatboat.
- 1. One side of a vessel above the .
- 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.
- See gangplank.
- Alternative name for a paddle on a paddlewheel.
- The chief bosun's mate (in the Royal Navy), responsible for discipline.
- bug shoe
- A length of hardened material placed on a shipworms. to protect the skeg from damage by
- 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 at the end of the 19th century.
- bulbous bow
- A protruding bulb at the bow of a ship just below the 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
- A merchant ship specially designed to transport unpackaged bulk cargo in its cargo holds.
- An upright wall within the hull of a ship, particularly a watertight, load-bearing wall.
- The extension of a ship's side above the level of the weather deck.
- bull ensign
- The senior ensign of a U.S. Navy command (i.e., a ship, squadron or shore activity).
- A glass window above the captain's cabin to allow viewing of the sails above deck.
- A private boat selling goods.
- bumpkin or boomkin
- 1. A , similar to a bowsprit, but which projects from the rather than the bow. May be used to attach the backstay or mizzen sheets 
- 2. An iron bar projecting outboard from a ship's side to which the lower and brace blocks are sometimes hooked.
- A built-in bed on board ship.
- A container for storing coal or fuel oil for a ship's engine.
- bunker fuel or bunkers
- Fuel oil for a ship.
- 1. Middle cloths of a square sail. 
- 2. Centre of a furled square sail. 
- Canvas apron used to fasten the bunt of a square sail to the yard when furled. 
- bunting tosser
- A signalman who prepares and flies flag hoists. Also known in the American Navy as a skivvy waver.
- 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.
- 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.
- 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).
- A small flag, typically triangular, flown from the masthead of a yacht to indicate yacht-club membership.
- A dish of ships biscuit crumbs and minced salt pork, usually a meal of last resort for officers when other food stores are exhausted.
- 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 .
- 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.
- cabin cruiser
- A type of powered pleasure craft that provides accommodation for its crew and passengers inside the structure of the craft. A cabin cruiser usually is 7.6 to 13.7 metres (25 to 45 ft) in length, with a powered pleasure craft larger than that considered a motor yacht.
- 1. An especially large or thick rope.
- 2. A cable length.
- cable length
- A measure of length or distance equivalent to 1⁄10 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.
- A small ship's kitchen or galley on deck.
- 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
- See lattice mast.
- 1. 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.
- 2. Floating platforms brought alongside for use by yard workers or crew.
- 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 .
- canal boat
- A specialized watercraft designed for operation on a canal.
- A ship designed to transit the locks of the Welland Canal.
- canister shot
- 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 of a such that it is pointed like a bow, rather than squared off as a .
- A collective term for all of the on a vessel; the total area of all sails aboard her may be expressed as the area of her canvas. Care needs to be taken in understanding what may appear to be an area of canvas for a sail; a stated number may be the length of canvas that is needed off the roll, and it was made several different standard widths.
- A fitting or band used to connect the head of one to the lower portion of the mast above.
- Cape Horn fever
- A feigned illness from which a malingerer is pretending to suffer.
- Cape Horn roller
- 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.
- A backstay leading from a mast cap to the ship's side.
- 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.
- (of a vessel) To list so severely that the vessel rolls over, exposing the keel. On large vessels, this often results in the sinking of the ship. Compare .
- A large with a vertical axis used to wind in anchors or to hoist 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.
- 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 U.S. Navy, U.S. Coast Guard, U.S. Public Health Service, and National Oceanic and Atmospheric Administration, 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 U.S. Army, U.S. Marine Corps, or U.S. 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 U.S. 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
- An unpowered barge with railroad tracks mounted on its deck, used to move railroad cars across water obstacles.
- A small, highly maneuverable sailing ship with a lateen rig, used by the Portuguese in the 15th and 16th centuries to explore along the West African coast and into the Atlantic Ocean.
- Referring to the four main points of the compass: north, south, east, and west. See also bearing.
- Tilting a ship on its side, usually when beached, to clean or repair the hull below the .
- cargo liner
- 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, however, although technically cargo ships, are routinely thought of as constituting a completely separate category.
- 1. In the Age of Sail, a warrant officer responsible for the hull, , , and of a vessel, and also for sounding the well to see if the vessel was .
- 2. A senior rating responsible for all of the woodwork aboard a vessel.
- carpenter's walk
- On a tall ship, a is a narrow unlit passageway or bulkhead often with a low (four-foot) ceiling that is fitted around the hull at its waterline. The carpenter's walk allowed the ship's carpenter to tour the entire waterline area of a ship to inspect it for water leaks. Because of its dark and seldom-visited nature and location far below decks, it was also sometimes used by mutinous sailors as a secluded place to plan a rebellion against the ship's officers.
- A three- or four-masted oceangoing sailing ship used by Western Europeans in the Atlantic Ocean from the 15th through the early 17th centuries.
- An aircraft carrier.
- 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.
- carry on
- Resume work or assigned duties.
- 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.
- A method of constructing a wooden hull in which planks are butted edge-to-edge on a robust frame, so giving a smooth hull surface; traditionally the planks are not attached to each other, only to the frame, and have only a caulking sealant between them to make them watertight. Contrast clinker-built.
- A light metal structure, usually incorporating a deck, built over the upper surface of a pressure hull to create a flat surface on which crew members can walk. A feature of submarines built prior to the mid-20th century, but not of more modern submarines. 's
- 1. To prepare an anchor after raising it by lifting it with a to the cathead, prior to securing (fishing) it alongside for sea. An anchor raised to the cathead is said to be catted.
- 2. The cat o' nine tails.
- 3. A cat-rigged boat or catboat.
- cat o' nine tails
- A short, multi-tailed whip or flail kept by the bosun's mate to flog sailors (and soldiers in the army) who had committed infractions while at sea. When not in use, the cat was often kept in a baize bag, a possible origin for the term "cat out of the bag". "Not enough room to swing a cat" also derives from this.
- Any vessel with two hulls. Compare .
- A cat-rigged vessel with a single mast mounted close to the bow and only one sail, usually on a gaff.
- The curve of a deployed anchor chain.
- A short rope or iron clamp used to brace in the toward the masts so as to give a freer sweep to the .
- 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.
- To create a seal between structures. In traditional carvel construction, this involved hammering (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.
- Navigation by the position of celestial objects, including the stars, Sun, and Moon, using tools aboard ship such as a sextant, chronometer, and compass, as well as published tables of the expected positions of celestial objects on specific dates. Celestial navigation was the primary method of navigation until the development of electronic global positioning systems such as LORAN and GPS.
- 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; e.g. limber boards, , , etc. 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.
- center of effort
- The point of origin of net aerodynamic force upon a , roughly located in the geometric center of the sail, though the actual position of the center of effort will vary with , sail trim, or airfoil profile, boat trim, and .
- 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 perfectly balanced sailboat, the center of effort will align vertically with the center of lateral resistance. If this is not the case, the boat will be unbalanced and will exhibit either lee helm or and will be difficult to control.
- 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".
- A wooden board or metal plate which can be pivoted through a fore-and-aft slot along the centerline in the hull of a sailing vessel, functioning as a retractable keel to help the boat resist leeway by moving its center of lateral resistance. Very common in dinghies, but also found in some larger boats. A daggerboard serves the same purpose but slides vertically rather than pivoting.
- 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 and .
- 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.
- Cannonballs linked with short lengths of chain, designed to be especially damaging to and .
- chain plates
- Iron bars bolted to a ship's side to which the deadeyes or rigging screws of the lower figging and the back-stays are bolted.
- A broad, thick plank that projects horizontally from each of a ship's sides abreast a (distinguished as the fore, main, or mizzen channel accordingly), serving to extend the base for the , which support the mast.
- Small platforms built into the sides of a ship to spread the to a more advantageous angle. Also used as a platform for manual depth sounding.
- 1. A small boat that functions as a , , or gondola.
- 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 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) the moment the vessel arrives in port.
- 2. (obsolete usage) A crew member avoiding duties with a feigned illness, usually after leaving port.
- Charlie/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 17th to the 19th centuries for a merchant ship it chartered to make a single, often one-way, voyage 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 in much the same way as what the company called an extra ship, though the company usually hired charter ships on special terms and for much shorter periods.
- A compartment from which the ship was navigated, especially in the Royal Navy.
- An electronic instrument that places the position of the ship (from a GPS receiver) onto a digital 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
- 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 ( ) were used to ward off pursuing vessels. Unlike guns pointing to the side, chasers could be brought to bear in a chase without slowing down the vessel.
- A decked commercial sailing vessel engaged in the transportation of fresh fish directly from fishing grounds to ports in Brittany between the 18th century and around the third quarter of the 19th century. Three- luggers replaced the vessels originally serving in this role; the luggers then were replaced successively by dundees, brigs, and schooners.
- 1. Wooden blocks at the side of a .
- 2. Flat plates of iron or wood bolted to the to form angle supports for the cross-trees.
- 3. The sides of a block or gun-carriage.
- chief engineer
- The senior engineering officer (abbreviated ChEng).
- 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.
- 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 and Dutchman's chock.
- Rigging blocks that are so tight against one another that they cannot be further tightened.
- A timekeeping device accurate enough to be used aboard a ship to determine longitude by means of celestial navigation. The invention of the marine chronometer in the 18th century was a major technical achievement for maritime navigation.
- cigarette boat
- See go-fast boat.
- A fortified safe room on a vessel to take shelter in the event of 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".
- 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, while one not meeting it 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 .
- clean slate
- At the helm, the would record details of speed, distances, headings, etc. on a slate. At the beginning of a new watch the slate would be wiped clean.
- To perform customs and immigration legalities prior to leaving port.
- A stationary device used to secure a rope aboard a vessel.
- 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.
- One of the lower corners of a square sail, or, on a triangular sail, the corner at the end of the boom.
- Lines used to truss up the clews, the lower corners of square sails. Used to reduce and stow a barge's .
- 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.
- 1. A sailing vessel designed primarily for speed. While the Baltimore Clippers and opium clippers could be rigged differently, often as , and a small number of 19th-century clippers were built as barques. clipper ships of the middle of the 19th century are well known, others, such as
- 2. A .
- close aboard
- Very near (the ship).
- (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.
- 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 of obtaining a good firing angle on a pursuing vessel. See kedge.
- C.O. (or CO)
- An abbreviation for commanding officer.
- coal hulk
- A hulk used to store coal.
- coal trimmer
- A person responsible for ensuring that a coal-fired vessel remains in " " (evenly balanced) as coal is consumed on a voyage.
- 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.
- The raised edge of a hatch, cockpit, or skylight, designed to help keep out water that pools on the surface above.
- A coastal trading vessel; a shallow-hulled ship used for trade between locations on the same island or continent.
- A type of open traditional fishing boat with a flat bottom and high bow which developed on the northeast coast of England.
- To angle a away from the horizontal so that it is out of the way for loading or unloading, or so that the ship may lie alongside another ship without the yards touching.
- A seating area (not to be confused with the deck) towards the of a small-decked vessel that houses the controls.
- An insulating space between two watertight bulkheads or decks within a ship.
- A type of sailing ship, with a single Baltic Sea region, in seagoing trade from the 12th through the 14th centuries. It had a distinctive hull design: the flat bottom was carvel-built and the sides were clinker-built.: 225–227 and a single first developed in the 10th century and widely used, particularly in the
- A wedge used to assist in the aiming of a cannon; an older form of "quoin".
- 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 that gives 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 made 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.
- A long, curving wave breaking on the shore.
- come about
- 1. To .
- 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.
- commanding officer
- The officer in command of a warship. Also called "CO", "captain" (regardless of rank), "skipper", or "the old man".
- 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.
- commissioning pennant
- A pennant flown from the of a warship. Also called a masthead pennant.
- 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 . 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 captain.
- 2. (rank) A military rank used in many navies that is superior to a navy captain but below a . 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
- An air-filled tube, usually armored, allowing speech between the conning tower and the below-decks control spaces on a warship.
- A raised and windowed hatchway in a ship's deck, with a ladder leading below and the hooded entrance-hatch to the main cabins.
- 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.
- 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.
- 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.
- Unpowered Great Lakes vessels, usually a fully loaded , 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.
- container ship
- A cargo ship that carries all of her cargo in truck-size intermodal containers.
- A group of ships traveling together for mutual support and protection.
- An amateur .
- A device used to correct the ship's compass, e.g. by counteracting errors due to the magnetic effects of a steel hull.
- 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.
- 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 U.S. Navy, it is referred to as a .
- 2. A lightly armed and armored warship of the 20th and 21st centuries, smaller than a frigate and capable of transoceanic duty.
- A partial load.
- 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).
- The part of the above the that extends beyond the stock culminating in a small . A long counter increases the waterline length when the boat is heeled, so increasing hull speed. See also .
- To deliberately flood compartments on the opposite side from already flooded ones. Usually done to reduce a list.
- country ship
- A term used by the British East India Company from the seventeenth to the nineteenth century for a merchant ship owned by local owners east of the Cape of Good Hope which traded within that area and gathered cargoes for shipment west of the Cape to England (later the United Kingdom) by the company's "chartered ships", "extra ships", and " ". "Country ships" were strictly prohibited from trading west of the Cape, which would violate the company's strict monopoly on that trade. Country ships were also important in the opium trade from India into China until supplanted by the faster opium clipper.: 51
- 1. The direction in which a vessel is being steered, usually given in degrees.
- 2. The lowest square sail on a square rigged mast, except where that mast is the mizzen – in which case the name cro'jack (cross-jack) or mizzen-sail is used.
- 1. A ship's ventilator with a bell-shaped top that can be swiveled to catch the wind and force it below.
- 2. A vertical projection of a ship's funnel that directs the smoke away from the bridge.
- The helmsman or crew member in command of a boat.
- A winch used for raising the leeboard, with a barrel for pulling in the sheets.
- A fishing vessel rigged for crab fishing.
- crane vessel or crane ship
- A ship with a crane and specialized for lifting heavy loads.
- cranse iron
- The metal fitting mounted at the end of a bowsprit to which the forestay (or jibstay), bobstay, and bowsprit shrouds are attached. It is also where the tack of the outermost headsail is fastened.
- crash rescue boat or crash boat
- A term used in the United States to describe military high-speed offshore rescue boats, similar in size and performance to motor torpedo boats, used to rescue pilots and aircrews of crashed aircraft.
- Crazy Ivan
- U.S. 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.
- 1. On warships and merchant ships, all of those members of a who are not officers.
- 2. On leisure vessels with no formal chain of command, all of those persons who are not the skipper or passengers.
- crew boat
- A vessel specialized for the transportation of offshore support personnel and cargo to and from offshore installations such as oil platforms, drilling rigs, drill ships, dive ships, and wind farms. Also known as a fast support vessel or fast supply vessel.
- crew management
- The services rendered by specialised shipping companies to manage the human resources and manning of all types of vessels, including recruitment, deployment to vessel, scheduling, and training, as well as the ongoing management and administrative duties of seafarers, such as payroll, travel arrangements, insurance and health schemes, overall career development, and day-to-day welfare. Also known as crewing.
- A loop of rope, usually at the corners of a sail, for fixing the sail to a . They are often reinforced with a metal eye.
- The square sail set on the lower mizzen yard of a ship. Many full-rigged ships would not set a sail in this position, as it would be interfered with by the 
- cross the line
- Cross the equator.
- Two horizontal struts at the upper ends of the of sailboats, used to anchor the shrouds from the mast. Lateral spreaders for the topmast shrouds (standing back stays).
- crow's nest
- A constructed with sides and sometimes a roof to shelter the lookouts from the weather, generally by whaling vessels. The term has also become generic for what is properly called a 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 are sometimes called ocean liners.
- 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 battle fleet. Cruisers carried out functions performed previously by the cruising ships (sailing frigates and sloops-of-war) of the Age of Sail.
- 2. From the early 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 of 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 attacks against such forces; virtually indistinguishable from large destroyers since the late 20th century.
- 4. A yacht with a cabin(s) containing the facilities for living aboard, thus capable of making .
- Metal Y-shaped pins used to fix oars while rowing.
- A small cabin in a boat; a cabin, for the use of the captain, in the after part of a sailing ship under the .
- 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 that closes under tension.
- 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 by bypassing the proper procedures.
- cut of his jib
- The "cut" of a sail refers to its shape. Since this would often 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. During the 16th and 17th centuries, the ships of different nations used visually distinctive types of jibs that could be determined at a distance, providing an easy way to determine friend from foe. Also used figuratively of people.
- 1. A sailing vessel defined by its rig. In European waters this is a single-masted fore and aft rig with two or more headsails In North American waters, the definition also considers whether or not the bowsprit is permanently fixed and also takes into account the position of the mast. A standing (permanently fixed) bowsprit and a forward mast position, but with two or more headsails would be classed as a sloop in the North American definition. A running bowsprit, a forestay (carrying a staysail) that is fixed to the stemhead, a jib that is set flying and a mast position that is more aft is a cutter.
- 2. A type of powered by sail or oars, though more optimised for sail than many types of ship's boat.
- 3. A small- or medium-sized vessel used by governmental agencies or law enforcement in the exercise of official authority, such as harbor pilots' cutters, U.S. Coast Guard cutters, and UK Border Agency cutters.
- 4. A type of decked sailing vessel originating in the early 18th century designed for speed. Originally this was just a hull type, but came to refer to the rig, which was single masted with both fore and aft and square sails. Very large sail areas were available for light winds. Many were used as small warships.
- cutting out
- A surprise attack by small boats, often at night, against an anchored vessel in which the small-boat crews boarded and captured or destroyed the target vessel. Cutting out became a popular tactic in the latter part of the 18th century and saw extensive use during the Napoleonic Wars.
- The forward curve of the of a ship.
- A type of light centerboard that is lifted vertically; sometimes in pairs, with the leeward one lowered when beating.
- dan or dan-buoy
- A temporary marker buoy consisting of a long pole with flag and/or light at the top and, lower down, a float and a ballast weight to make it float vertically. May be used with or without an anchor to attach it to the sea bed. In naval use often marks a swept channel created by minesweeping. In other uses may mark fishing equipment (nets or pots), an anchor, or, most commonly, is attached to a lifebuoy to throw into the sea to mark the position of a .
- 1. A rig with a small abaft the .
- 2. In British usage, another name for a .
- 3. In British usage, a small after-sail on a yawl.
- A mine warfare vessel, usually a small , fitted for laying dans. Danlayers served as a part of flotillas during and immediately after World War II (1939–1945).
- To run dart; to run dead before the wind.
- 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 lifeboats.
- Davy Jones' Locker
- An idiom for the bottom of the sea.
- day beacon
- An unlighted fixed structure equipped with a dayboard for daytime identification.
- The moment at dawn where, from some point on the , a lookout can see above low-lying mist around the ship.
- The daytime identifier of an aid to navigation presenting one of several standard shapes (square, triangle, or rectangle) and colors (red, green, white, orange, yellow, or black).
- day boat
- 1. A sailing boat without overnight accommodation, sometimes with a small cabin, used for pleasure sailing. Typically around 20 feet in length
- 2. (United States): a steamboat built for daytime service; as opposed to a .
- dead ahead
- Exactly ahead; directly ahead; directly in front.
- dead horse
- Debt owed for advanced pay. The "flogging a dead horse" ceremony at sea celebrated discharge of the debt.
- dead in the water
- Not moving (used only when a vessel is afloat and neither tied up nor anchored). The term is abbreviated to DIW by the U.S. Navy. It is often used to indicate that a pirate or drug runner vessel has been immobilised.
- dead run
- See .
- dead slow
- See .
- dead wake
- The trail of a fading disturbance in the water. See also .
- A wooden block with three holes (but no pulleys) spliced to a . It adjusts the tension in the of large sailing vessels, by lacing through the holes with a lanyard to the deck. It performs the same job as a .
- A .
- A strong shutter fitted over a porthole or other opening that can be closed in bad weather.
- dead reckoning
- A method of navigation that estimates a ship's position from the distance run measured by the log and the course steered. If corrections for factors such as tide and leeway are then made, this provides an estimated position. Dead reckoning contrasts with fixing a position with astronomical navigation or satellite navigation. Some sources consider that a dead reckoning position does include adjustments for wind and tide, so care is needed in interpretation of this term.
- The angle of the hull surface, relative to horizontal, either side of the keel and on a line drawn towards the turn of the bilge. Without any other qualifier, it is taken at the midships cross-section of the hull. This can be expressed in degrees or sometimes as a vertical linear measure (such as inches) at a standard distance from the keel. A hull with a lot of deadrise has an obvious "V" shape to the bottom of the hull, whereas no deadrise denotes a flat-bottomed hull. It is usually taken to be one of several measures of the "sharpness" of a hull. It can also be referred to as the "rise of floor".
- In a traditional wooden hull, blocks of timber on the top of the keel that form the shape of the hull where its section is too narrow for the method of construction employed elsewhere. It is often used forward of the .
- death roll
- In a keel boat, the act of broaching to , putting the into the water and causing a crash-gybe of the boom and , which sweep across the deck and plunge down into the water. During a death roll, the boat 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.
- The process of removing fuel from a vessel. After a shipwreck, a "debunkering" operation will be performed in an effort to minimize damage and protect the environment from fuel spills.
- 1. The top of a ship or vessel; the surface that is removed to accommodate the seating area.
- 2. Any of the structures forming the approximately horizontal surfaces in the ship's general structure. Unlike flats, they are a structural part of the ship.
- deck hand
- A person whose job involves aiding the deck supervisor in (un)mooring, anchoring, maintenance, and general evolutions on deck.
- deck supervisor
- The person in charge of all evolutions and maintenance on deck; sometimes split into two groups: forward deck supervisor and aft deck supervisor.
- The underside 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.
- A cabin that protrudes above a ship's deck.
- 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.
- 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.
- A process to reduce a warship's magnetic signature.
- A fee paid by a charter party to a shipowner if the time taken to load or unload a vessel exceeds the laytime – the amount of time stipulated for loading or unloading – specified in a voyage charter.
- depot ship
- A ship that acts as a mobile or fixed base for other ships and submarines or that supports a naval base.
- depth of hold
- The distance between the underside of the main deck (or its supporting beams) and the top of the limber boards (the part of the ceiling that lies alongside the keelson), measured at the middle frame. It is one of the key measurements in working out the measurement tonnage in most systems.
- A lifting device composed of one or pole and a boom or jib hinged freely at the bottom.
- A fee paid by a shipowner to a charter party if the time taken to load or unload a vessel is less than the laytime – the amount of time stipulated for loading or unloading – specified in a voyage charter.
- despatch boat
- An alternate spelling of dispatch boat.
- A type of fast and maneuverable small warship introduced in the 1890s to protect capital ships from torpedo boat attack, and 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, or missiles. Originally torpedo boat destroyer. In U.S. Navy slang, also called a tin can or small boy.
- destroyer depot ship
- See destroyer tender.
- destroyer escort
- A US Navy term for a smaller, lightly armed warship built in large numbers during World War II (and in 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 used to provide 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.
- destroyer tender
- A naval auxiliary ship designed to provide maintenance support to a flotilla of destroyers or other small warships. Known in British English as a destroyer depot ship.
- 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 , which would be difficult to get at, requiring a cranked caulking iron, and a restricted swing of the caulking mallet.
- devil to pay
- "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.
- devil's claw
- A type of chain stopper often used to secure an anchor in its hawsepipe. Consists of a two-pronged hook that fits over a link of chain, a and a short chain fastened to a strong point.
- 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.
- Glass prisms that were laid between the wooden deck planks to allow natural light below were referred to as diamonds due to the sparkle they gave off in the sunlight.
- 1. A type of small boat, often carried or towed as a by a larger vessel.
- 2. 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.
- dipping the eye
- A method of attaching more than one hawser to a single bollard, so that each can be lifted off without disturbing the other(s). The second hawser is passed under the first, then up through the eye of the first (hence the name), before being secured over the bollard.
- dipping the flag
- A method of rendering honors at sea by lowering and raising a ship's flag.
- 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.
- 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.
- disposable ship
- A barely seaworthy ship of the 19th century assembled from large timbers lashed or pegged together and designed to make a single voyage from North America to the United Kingdom and then to be disassembled so that her timbers could be sold, thus avoiding high British taxes on lumber imported as cargo. When British taxes on imported lumber fell, the construction of disposable ships ceased.
- To reduce in rank or rating; to demote.
- distinctive 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.
- ditty bag
- Bag or box for personal items.
- 1. Especially in the late 19th and early 20th centuries, a permanent battle formation of a fleet, often smaller than a squadron, equipped and trained to operate as a tactical unit under the overall command of a higher command, such as a fleet or squadron.
- 2. Especially in modern usage, an administrative naval command, smaller than a squadron and often subordinate to an administrative squadron, responsible for the manning, training, supply, and maintenance of a group of ships or submarines but not for directing their operations at sea.
- Divisional Transport Officer
- In British usage, a shore-based naval officer responsible for the efficient working of the and boats of the flotilla, division, or under his charge.
- 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 that accommodates vessels tied up at the piers or wharves.
- 3. To tie up along a pier or wharf.
- A facility where ships or boats are built and repaired. Routinely used as a synonym for shipyard, although dockyard is sometimes 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.
- A hood forward of a hatch or cockpit to protect the crew from wind and spray. Can be soft or hard.
- Device to secure doors and hatches. Typically used for watertight openings, but can apply elsewhere. "Dogging the hatches" is a common phrase.
- 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.
- 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.
- A small weather vane, sometimes improvised with a scrap of cloth, yarn, or other light material mounted within sight of the helmsman. See .
- The equatorial trough, with special reference to the light and variable nature of the winds generally encountered there.
- dolly winch
- A small winch mounted on the , used as an alternative to the brails winch when that is obstructed in some way (e.g. by deck cargo).
- A structure consisting of a number of piles driven into the seabed or riverbed as a marker.
- dolphin striker
- A spar protruding vertically beneath a bowsprit, usually attached to the boswprit cap, used provide a mechanically advantageous run for the martingale stay, and other ropes of a ship's rigging.
- donkey engine
- A small auxiliary engine used either to start a larger engine or independently, e.g. for pumping water on steamships.
- One of a ship's engineering crew. Often a crewman responsible for maintaining a steam donkey, or any machinery other than the main engines. On some ships, the Petty Officer in charge of engineroom ratings.
- dorade box
- A dorade box (also called a dorade vent, collector box, or simply a "ventilator") is a type of vent that permits the passage of air in and out of the cabin or engine room of a boat while keeping rain, spray, and sea wash out.
- A shallow-draft, lightweight boat, about 5 to 7 metres (16 to 23 ft) long, with high sides, a flat bottom, and sharp bows. Traditionally used as fishing boats, both in coastal waters and in the open sea.
- (of the arrangement of oars on a boat) having two oarsmen seated on each : 135 , each of whom operates one oar on their side of the boat. This contrasts with , where only one oarsman is seated on each thwart operating one oar on one side of the boat, with the oars alternating between port and starboard along the length of the boat. A third arrangement is to have one rower on each thwart working two oars, one on each side of the boat.
- The practice of loading smoothbore cannon with two cannonballs.
- doubling the angle on the bow
- A technique for establishing the distance from a point on land, such as a headland that is being passed. This is a type of which requires no plotting on the chart. The ship is sailed on a constant course and speed. The distance shown on the log is noted when the of a fixed point is taken, and the increase in that bearing is watched until it is twice the original bearing, and the log is read again. The distance travelled between the two bearings is the distance of the ship from the fixed point when the second bearing was taken. Allowances for tidal streams may or may not be allowed for, depending on the accuracy required.
- Dover cliffs
- A slang term for very rough seas with large white-capped waves.
- 1. Travel downstream, with a following current.
- 2. Eastward travel in the Great Lakes region (terminology used by the Saint Lawrence Seaway Development Corporation).
- The entry of water through any opening into the hull or of an undamaged vessel, such as an open door or , loose or open hatch, ventilator opening, etc. Downflooding can occur due to a ship′s , if she heels or lists, or if she becomes totally or partially submerged.
- A line used to control either a mobile , or the shape of a sail. A downhaul can also be used to retrieve a sail back on deck.
- An extra strip of canvas secured below a bonnet, further to increase the area of a course.
- The depth of a ship's keel below the .
- dragon boat
- 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.
- 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 to , between mastheads (if the vessel has more than one mast), and then down to the , 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 (e.g. that of a flag officer on board), in addition to the ensign flown in the usual position at the .
- dressing down
- 1. Treating old sails with oil or wax to renew them.
- 2. A verbal reprimand.
- dressing lines
- Lines running from to , between mastheads, and then down to the , to which flags are attached when a ship is dressed overall.
- A type of fishing boat designed to catch herring in a long drift net, long used in the Netherlands and Great Britain.
- Overboard and into the water (e.g. "it fell into the drink").
- The large sail flown from the gaff.
- The fifth Thomas W. Lawson, was normally called the pusher-mast. of a six-masted barquentine or gaff . It is preceded by the jigger mast and followed by the . The sixth mast of the only seven-masted vessel, the gaff schooner
- See disposable ship.
- 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. See also .
- A technique of maintaining when going downstream with neither engine nor wind to sail. The vessel uses its anchor to draw itself head-to-stream, then lifts the anchor and drifts stern-first downstream, ferry gliding to maintain position within the stream. As steerage begins to reduce, the vessel anchors again and then repeats the whole procedure as required.
- 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.
- drying harbour
- A harbour where the water wholly or partly recedes as the tide goes out, leaving any vessel moored there aground.
- 1. Loose packing material used to protect a ship's cargo from damage during transport. See also fardage.
- 2. Personal baggage.
- Dutch barge
- Any of several types of traditional flat-bottomed shoal-draught sailing barge, originally used for carrying cargo in the Zuyder Zee and on the rivers of the Netherlands.
- Dutch built
- Term of abuse implying shoddiness or (when directed at a person) stupidity or stubbornness, usually embellished with other oaths and insults tagged on fore and aft.
- Small lines by which the uppermost corners of the largest sails are secured to the .
- 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
- The measurement of the depth of a body of water using a SONAR device. See also and .
- A condition in which a sailing vessel (especially one that sails poorly to ) 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.
- 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.
- 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.
- 1. (flag) The principal flag or banner flown by a ship to indicate her nationality.
- 2. (rank) The lowest grade of commissioned officer in the U.S. Navy.
- escort carrier
- A type of aircraft carrier, smaller and slower than a fleet carrier, used by some navies in World War II to escort convoys, ferry aircraft, and provide air support for amphibious operations.
- estimated position
- An approximate geographical position obtained by making allowances for leeway, tide, and currents to a dead reckoning position (which is calculated from the distance run and the course steered).
- executive officer
- The officer second in command on a warship. Also called "X.O." and "Number One".
- extra ship
- A term used by the British East India Company from the seventeenth to the nineteenth century for merchant ships it hired to make voyages for 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. "Extra ships" were chartered for a single round-trip voyage beginning during a single sailing season (September to April) and augmented the voyages of " ", which were merchant ships under long-term charter to make repeated voyages for the company over many seasons. However, if an "extra ship" operated well and the company needed its services, the company often chartered it repeatedly over a number of seasons.
- 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 of 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 frequently employed in moorings and docking lines, among other uses.
- factory ship
- A large oceangoing vessel with extensive on-board facilities for processing and freezing caught fish or whales. Some also serve as for smaller fishing or whaling vessels. Those used for processing fish are also known as fish processing vessels.
- 1. A smooth curve, usually referring to a line of the hull with minimum localised 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.
- A device used to keep a line or chain running in the correct direction or to give it a fair lead to prevent it rubbing or fouling.
- 1. (n) A structure that improves the streamlining of a vessel.
- 2. (v) The process of making a curve or structure fair.
- 1. A structure that improves the streamlining of a vessel.
- 2. On submarines: The superstructure (conning tower, sail,etc) of the boat.
- 1. A navigable channel (e.g. in a harbor or offshore) that is the usual course taken by vessels in the area.
- 2. In military and naval terms, a channel from offshore, in a river, or in a harbor that has enough depth to accommodate the draft of large vessels.
- A single turn of rope in a coil or on a drum. A group of fakes is known as a : 200, 286 . See also fake down.
- fake down
- To lay a coil of rope down so that it will run easily; that is, with rope feeding off the top of the coil and the bitter end at the bottom. Often confused with flake. See also .
- 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.
- The part of the that is hauled upon.
- fall off
- To change the direction of sail so as to point in a direction that is more downwind; to bring the bow leeward. This is the opposite of pointing up or heading up.
- The aft end of a ship, also known as the .
- Wood placed in the bottom of a ship to keep cargo dry. See also dunnage.
- fashion boards
- Loose boards that slide in grooves to close off a companionway or cabin entrance.
- Fastened or held firmly (e.g. "fast aground": stuck on the seabed; or "made fast": tied securely).
- fast combat support ship
- The largest type of U.S. Navy combat logistics ship, designed to serve as a combined oiler, ammunition ship, and supply ship. The first fast combat support ship entered service in the mid-1960s.
- fast supply vessel
- See crew boat.
- fast support vessel
- See crew boat.
- 1. A unit of length equal to 6 feet (1.8 m), roughly measured as the distance between a man's outstretched hands. Particularly used in as a measurement of the depth of a body of water.
- 2. To measure the depth of water; to engage in .
- A person engaged in to determine the depth of water.
- A that uses sound waves to determine the depth of water.
- favored side
- The side of the course that gets you to the next mark faster, due to more wind, favorable shifts, less current, smaller waves, etc.
- A traditional wooden sailing boat with a Red Sea and eastern Mediterranean and particularly along the Nile in Egypt and Sudan, as well as in Iraq. consisting of one or two lateen sails, used in protected waters of the
- 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.
- A flexible bumper used in boating to keep boats from banging into docks or each other. Often an old car tire.
- A used to carry passengers, and sometimes vehicles and cargo, across a body of water.
- ferry glide
- To hold a vessel against and at an angle to the current/stream such that the vessel moves sideways over the bottom due to the effect of the current operating on the upstream side of the vessel.
- ferry slip
- A specialized docking facility designed to receive a ferryboat or train ferry.
- 1. The distance across water a wind or waves have traveled.
- 2. To reach a mark without .
- 1. A tapered wooden tool used for separating the strands of rope for splicing.
- 2. A bar used to fix an upper in place.
- fife rail
- A freestanding surrounding the base of a and used for securing that mast's sails' halyards with a series of belaying pins.
- A sailing boat with two masts with a standard rig consisting of a main dipping lug sail and a mizzen standing lug sail. Developed in Scotland and used for commercial fishing from the 1850s until the 20th century.
- U.S. Navy slang for a guided-missile frigate, especially of the Oliver Hazard Perry class, derived from its class designation ("FFG").
- fight his ship
- To fight his ship (or to fight her ship) is a naval term that denotes a captain taking their vessel into combat or directing their vessel in combat.
- fighting top
- An enlarged snipers armed with muskets or rifles. 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
- figure of eight
- A stopper knot.
- A symbolic image, particularly a carved effigy, at the head of a traditional sailing ship or early steamer.
- 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.
- Narrow 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 bow with her bow or facing the viewer's ship could be described as "fine on the starboard bow" of the viewer's ship.
- A specialized vessel equipped with firefighting equipment such as pumps and nozzles for fighting shipboard and shoreline fires.
- 1. A job associated with tending the fire for a boiler.
- 2. A U.S. Navy in the engineering department equivalent to .
- 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.
- fire room
- The compartment in which a ship's boilers or furnaces are stoked and fired.
- The classification for the largest sailing warships of the 17th through the 19th centuries. Such vessels often had up to three 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 . Also known as 'Jimmy the One' or 'Number One'. Removes his cap when visiting the mess decks as a token of respect for the privacy of the crew in those quarters. Officer in charge of cables on the forecastle.
- 2. In the U.S. 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.
- 1. To repair a or with a fillet of wood.
- 2. To secure an anchor on the side of a ship for sea (otherwise known as "catting".)
- 3. A slang term for a self-propelled torpedo.
- fisherman's reef
- A sailing tactic for handling winds too strong for the sail area hoisted when reefing the sails is not feasible or possible. The headsail is set normally while the is let out until it is constantly luffing. This creates a loss of force on the main and also reduces the efficiency of the headsail while still retaining sailing control of the vessel.
- fisherman's sail
- On a , the fisherman is a quadrilateral sail set between the two masts above the main staysail. It is used in light to moderate airs.
- The period after a ship is launched during which all the remaining construction of the ship is completed and she is readied for and delivery to her owners.
- fixed propeller
- A mounted on a rigid shaft protruding from the hull of a vessel, usually driven by an inboard motor; steering must be done using a . See also and .
- flag hoist
- A number of England expects that every man will do his duty". strung together to convey a message, e.g. "
- flag of convenience
- The business practice of registering a 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 under their command, in English-speaking countries usually referring to the senior officers of a navy, specifically to 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 U.S. 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.
- 1. A vessel used by the commanding officer of a group of naval ships. The term derives from the custom of commanders of such a group of ships, characteristically a flag officer, flying a distinguishing flag aboard the ship on which they are 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.
- To set down in folds, as in stowing a sail or to a cable on deck so that it is clear to run. Not to be confused with fake down.
- The maximum speed of a ship. Faster than "full speed".
- 1. A curvature of the topsides outward towards the gunwale.
- 2. A pyrotechnic signalling device, usually used to indicate distress.
- A Great Lakes slang term for a vessel without any self-unloading equipment.
- A rectangular, flat-bottomed boat with square ends used to transport freight and passengers on inland waterways in the United States during the 18th and 19th centuries.
- A slang term for an aircraft carrier.
- 1. Naval fleet: The highest operational echelon of command of ships commanded by a single person in a navy, and typically the largest type of naval formation commanded by a single person. In modern times, usually (but not necessarily) a permanent formation.
- 2. During the Age of Sail, a Royal Navy term for any naval command larger than a squadron in size, or commanded by a rear admiral and composed of five ships-of-the-line and any number of smaller vessels.
- 3. Merchant fleet, a collective term for the (known in the United Kingdom and Commonwealth countries the ) of a particular country.
- 4. Fishing fleet: A term for an aggregate of commercial fishing vessels, commonly used either to describe all fishing vessels belonging to a single country, operating in a single region, operating out of a particular port, or engaged in particular type of fishing (e.g., the tuna fishing fleet). The term does not imply that the vessels operate as part of a single organization.
- 5. Informally, any grouping (based on physical proximity or sharing of a common organizational subordination) of naval or civilian vessels.
- 6. Of a person, to move from one location to another aboard a vessel, or to change positions within a naval organization.
- 7. To move up a rope – especially when drawing the blocks of a tackle part – to allow a greater advantage in hauling.
- 8. To cause a rope or chain to slip down the barrel of a capstan or .
- 9. A former term for the process aboard a vessel of moving deadeyes when the become too long.
- 10. A location where barges are secured.
- fleet in being
- A naval force that extends a controlling influence on maritime operations without ever leaving port by forcing an opposing navy to maintain forces on station to oppose it in case it comes out to fight or to blockade it in port. A navy which operates its forces as a fleet in being generally seeks to avoid actual combat with an enemy fleet for fear of losing a naval battle and thereby its ability to influence events and activities at sea.
- To coil a line that is not in use so that it lies flat on the deck.
- flettner rotor
- A spinning cylinder that uses the Magnus effect to harness wind power to propel a ship.
- flight deck
- A flat deck on an aircraft carrier used for the launch and recovery of aircraft.
- flog the glass
- The act of vibrating or shaking a half-hour — used until the early 19th century to time the length of a watch — to speed the passage of the sand in order to get off watch duty earlier.
- The transverse structural timbers to which the longitudinal bottom planking is attached. The equivalent side timbers are called the frames. The keelson is fastened on top of the floors, bolting them to the keel. The planking is the exterior of the hull, while the ceiling is attached on top of the floors, and it forms the base of the hold.
- Any of the upper extremities of the floor of a vessel.
- 1. In naval usage, a group of warships under a single commander that is smaller than a fleet but otherwise not formally defined. A flotilla often is larger than a , and usually is made up of smaller vessels than those assigned to a squadron, but some flotillas are smaller than squadrons and some include larger vessels. In some navies, the term flotilla is reserved for naval formations that operate on inland bodies of water, while the terms fleet and squadron denote naval formations that operate at sea. A flotilla may be a permanent or temporary formation. In modern times, a flotilla sometimes is an administrative naval unit responsible for maintaining and supporting vessels but not for commanding their operations at sea.
- 2. Informally, a group of naval or civilian vessels operating together or in close proximity to one another.
- flotilla holiday
- A group of chartered that set out together on the same route.
- 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.
- Debris or cargo that remains afloat after a . See also jetsam.
- The wedge-shaped part of an anchor's arms that digs into the solid bottom beneath a body of water.
- flush deck
- An upper deck of a vessel that extends unbroken from to .
- flush decker
- 1. Any vessel with a flush deck.
- 2. A U.S. Navy destroyer of the World War I-era Caldwell, Wickes, or Clemson class, produced in very large numbers.
- flushing board
- A board inserted vertically in a cabin entrance.
- A Dutch transoceanic sailing cargo vessel, 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 with folding blades, furling so as to reduce drag on a sailing vessel when not in use.
- following sea
- Waves going in the same direction as a ship, or within 15° of the heading, at a speed slower than the ship. See for waves travelling faster than the ship.
- foo-foo band
- An impromptu musical band on late 19th-century sailing vessels, made up from members of the ship's crew.
- 1. The lower edge of any .
- 2. The bottom of a .
- 3. An Imperial unit of length equivalent to 12 inches (30 cm).
- If the foot of a sail is not secured properly, it is footloose, blowing around in the wind.
- A barge's boat or dinghy.
- Each yard on a sailing ship is equipped with a footrope for sailors to stand on while setting or stowing the sails.
- See Beaufort scale.
- Toward the bow of a vessel.
- fore-and-aft rig
- A sailing consisting mainly of sails that are set along the line of the keel rather than perpendicular to it. Such sails, and the vessel itself, are said to be fore-and-aft-rigged.
- Removable wooded beams running along the centre of the hold openings, beneath the hatches that they support.
- fore horse
- A transverse wooden or iron beam afore the main mast to which the foresail sheet is attached.
- (pronounced //) A partial deck above the upper deck and at the head of the vessel; traditionally the location of the sailors' living quarters. The name is derived from the castle fitted to bear archers in time of war.
- The lower part of the of a ship.
- The forward (i.e., front) part of a hold.
- foremast jack
- An enlisted sailor, one who is housed before the foremast.
- The part of the hold of a ship within the angle of the bow.
- 1. A fore-and-aft-rigged sail set on the foremast.
- 2. The lowest sail set on the foremast of a full-rigged ship or other vessel.
- A long line or cable reaching from the bow of the vessel to the , used to support the .
- A triangular sail set on the forestay.
- 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 ship′s bottom is foul when it is overgrown with marine life such as barnacles.
- 3. An area of water treacherous to navigation due to many shallow obstructions such as reefs, sandbars, rocks, etc.
- 4. A breach of racing rules.
- 5. Foul the range: To block another vessel from firing her guns at a target.
- A slang term for , the foul-weather clothing worn by sailors.
- To fill with water and sink.
- four piper
- A term sometimes used to refer to United States Navy four-funneled destroyers of the Bainbridge, Paulding, Wickes, and Clemson classes, all built for service in World War I.
- fourth rate
- In the British Royal Navy during the first half of the 18th century, a mounting between 46 and 60 guns.
- A transverse structural member that 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.
- The height of a ship's hull (excluding the superstructure) above the ; 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.
- A cargo ship.
- 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 U.S. Navy from the 1950s until the 1970s, a type of guided-missile antiaircraft ship built on a destroyer-sized hull, all of which were 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 in a tricky sea (a serious risk for vessels). 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 , all of them . A full-rigged ship is said to have a "ship rig".
- full steam ahead
- With as much speed as possible.
- 1. (funnel) Also stack. The smokestack of a ship, used to expel boiler steam and smoke or engine exhaust.
- 2. Ventilation funnel: A curved, rotatable tube protruding from the deck of a vessel, designed to direct fresh air into her interior.
- Furious Fifties
- Strong westerly winds found in the Southern Hemisphere, generally between the latitudes of 50 and 60 degrees. They are stronger than the similar "Roaring Forties" to their north.
- To roll or gather a against its or .
- A narrow, light, and fast ship with a shallow draft, powered both by oars and sail, with a single mast carrying a lateen sail; a favorite of North African corsairs during the 16th and 17th centuries.
- Boiler component where fuel is burned.
- futtock shrouds
- Rope, wire, or chain links in the rigging of a traditional ship running from the outer edges of a downwards and inwards to a point on the or lower . They carry the load of the shrouds that rise from the edge of the top, preventing the top from tilting relative to the mast.
- Pieces of timber that make up a large transverse frame.
- 1. (gaff rig) A that holds the upper edge of a four-sided fore-and-aft-mounted sail. On a hoisting gaff, the lower end is supported by gaff jaws which partly encircle the mast; it is hoisted using and halliards. A standing gaff remains aloft, its sails brailed when not in use.
- 2. (fishing gaff) A hook on a long pole used to haul in fish.
- gaff rig
- A boat rigged with a four-sided fore-and-aft sail set abaft the mast, its head being spread by a gaff. The gaff may be standing (permanently in position) with the sail being brailed up to the gaff when not in use, or, more commonly, is hoisted using two halliards: the peak and the throat.
- gaff topsail
- A fore-and-aft sail set above a gaff-rigged sail, with the clew sheeted to the end of the gaff.
- gaff vang
- A line rigged to the end of a gaff and used to adjust a gaff sail's .
- See ghali.
- See ghali.
- 1. An oared warship of the 16th century equipped with a gun deck; larger and equipped with more sails than a galley.
- 2. A flat-bottomed commercial sailing vessel of the North Sea and western Baltic Sea.
- A large, multi-decked sailing ship with a prominent, squared-off, raised , generally carrying three or more , typically lateen fore-and-aft-rigged on the rear mast and on the and foremast. Galleons were used primarily as armed cargo carriers and sometimes as by European states from the 16th to the 18th centuries.
- 1. (galley (kitchen)) The compartment of a ship where food is cooked or prepared; a ship's kitchen.
- 2. (galley) A type of ship propelled by , used especially in the Mediterranean for warfare, piracy, and trade from the 8th century BC to the 16th century AD, with some in use until the early 19th century.
- 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.
- See fusta.
- A meeting of two (or more) 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.
- gammon iron
- The bow fitting that clamps the bowsprit to the .
- A movable bridge used in boarding or leaving a ship at a pier.
- An opening in the bulwark of a ship to allow passengers to board or leave the ship.
- A rope running through a block at or near the , with both ends reaching the deck. It is used solely for hoisting and lowering crew members and/or tools into the for maintenance and repair work.
- The illegal practice of mixing cargo with garbage.
- The closest to the keel (from Dutch gaarboard).
- garboard planks
- The planks immediately on either side of the keel.
- Any refuse or rubbish discarded into a refuse container or dustbin, also known as "gash fanny" (South African Navy).
- A rope used to secure a sail (particularly the ) when stowed.
- gate ship
- An alternative term for a .
- A collective term for a vessel's and .
- Ice cream, snacks, etc. Also the place selling such items.
- general quarters
- See battle stations.
- A large, lightweight sail used for sailing a fore-and-aft rig down or across the wind, intermediate between a genoa and a .
- A large jib, strongly overlapping the .
- Any of several types of galley-like ships from the Nusantara archipelago in Southeast Asia. The term refers both to Mediterranean vessels built by local people and to native vessels with Mediterranean influence.
- To sail slowly when there is apparently no wind.
- ghost fleet
- In the modern United States, an informal term for a .
- See gybe.
- A type of open boat designed primarily for propulsion under oar, but often fitted with a sailing rig for appropriate conditions. Used most often for the swift transport of one or a few people, as in a pilot gig or as a naval ship's boat. In U.S. Navy usage, a captain's gig is reserved for use by a ship's captain and, in modern times, is a power-boat.
- A fishing vessel that employs gillnetting as its means of catching fish.
- A pole that is attached perpendicular to a , to be used as a lever for raising the mast.
- 1. Said of a vessel moored by cables to two anchors in such a way that the force of a current or tide causes her to swing against one of the cables.
- 2. To capsize because of forces exerted on a cable by another vessel attached to it. Tug girting specifically refers to girting that causes a to capsize because of forces placed on a cable attached to her by another vessel attached to the same cable.
- In a situation where two vessels are approaching one another so as to involve a risk of collision, the vessel directed to keep out of the way of the other.
- 1. A marine barometer. Older barometers used mercury-filled glass tubes to measure and indicate barometric pressure.
- 2. A .
- Global Positioning System (GPS)
- A satellite-based radionavigation system providing continuous worldwide coverage of geolocation and time information to air, marine, and land users wherever there is an unobstructed line of sight to at least four GPS satellites developed and operated by the United States Department of Defense but publicly available for use by anyone with an enabled GPS receiver.
- go-fast boat
- A small, fast boat designed with a long narrow platform and a planing hull to enable it to reach high speeds. Colloquially equivalent to a "rum-runner" or a "cigarette boat".
- goat locker
- A mess hall reserved for chief petty officers in the United States Navy.
- going about
- Changing from one to another by going through the wind. See also gybe.
- 1. A traditional, flat-bottomed Venetian rowing boat.
- 2. An alternative term for a gundalow.
- A fitting that attaches a boom to a yet allows it to move freely.
- (of a fore-and-aft-rigged vessel) Sailing directly away from the wind, with the sails set on opposite sides of the vessel (e.g. with the to port and the jib to starboard) so as to maximize the amount of canvas exposed to the wind. See also .
- 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. Intended specifically to injure personnel and damage more than to cause structural damage.
- 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.
- See Cape Horn roller.
- The practice of navigating a vessel along the arc of a great circle. Such routes yield the shortest possible distance between any given pair of points on the surface of the Earth.
- A passage of two vessels moving in the opposite direction on their sides, so called because the green navigation light on one of the vessels faces the green light on the other vessel.
- A British term used in the 18th and 19th centuries for any Arctic Ocean or northern waters near the Arctic. operating in the
- A large metal cross-frame on which vessels are placed at high water for examination, cleaning, and repairs after the tide falls.
- A temporary eye in a line (rope).
- The tendency of a ship to turn into the wind despite the efforts of the helmsman, usually due to either the design of a ship or more commonly the incorrect distribution of weight on and within the hull.
- A Cockney (London dialect) name for a barge.
- Watered-down pusser's rum consisting of half a gill with an 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. Specific quantities of grog were often traded illegally as a form of currency; 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). Additional issues of grog were made on the command " " for celebrations or as a reward for performing especially onerous duties. The Royal Navy discontinued the practice of issuing rum in 1970.
- Drunk from having consumed a lot of grog.
- 1. A metal or plastic ring inserted in canvas to prevent wear.
- 2. A ring of rope.
- 3. An inexperienced surfer or extreme sports participant.
- The bed of the sea; the underwater surface or sea floor to which an anchor holds.
- When a ship (while afloat) touches the bed of the sea, or runs aground. A moored vessel that grounds as the tide goes out is said to "take the ground".
- A substantial foundation of wood or stone for the blocks on which a vessel is built, typically lying on either side of the keel of a ship under construction, which also serves to support and guide the blocks when they slide to carry the vessel into the water when she is launched.
- A small iceberg or ice floe barely visible above the surface of the water.
- Another name for a , coined after the emergence of the transatlantic slave trade from Africa in the 15th century.
- 1. (on an oceangoing sidewheel ) Horizontal structures, usually of wood, built around the just above their lowest point and extending a short distance forward and aft, designed to protect them from damage and to provide additional support for the paddle shaft.
- 2. (on an American sidewheel steamboat) Extensions of the main deck beyond the hull to the outer extremity of the paddle boxes, and tapering to the bow and (thus giving the deck a characteristic oval shape), to increase the available deck space for passengers, cargo, and/or machinery.
- guard ship
- 1. Any vessel that makes the rounds of a fleet at anchor to see that due watch is kept at night.
- 2. A stationed at a port or harbour to act as a guard there.
- 3. In former times in the British Royal Navy, a ship that received men impressed for naval service, often the flagship of the admiral commanding along the coast.
- 4. 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, 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.
- Falsifying of records and reports.
- A type of flat-bottomed sailing barge with a single large lateen sail brailed to a heavy Maine and New Hampshire from the mid-17th century to the early 20th century. Sometimes referred to as a gondola in period accounts. , used on rivers in
- gunner's daughter
- See kissing the gunner's daughter.
- An opening in the side of a ship or in a turret through which a gun fires or protrudes.
- gunter rig
- A fore-and-aft sail set abaft (behind) the mast, approximately triangular in shape, with the top half of the luff (front) of the sail attached to a which extends the sail above the top of the mast. The yard is raised and lowered with the sail. This traditional sail is popular in small boats and produces aerodynamic performance close to that of the highly developed Bermuda rig.
- Generally, the upper edge of the hull; more specifically, in an open (undecked) boat of timber construction, the longitudinal stringer that connects the top of the ribs.
- A mechanical crank used to set and retrieve fishing lines.
- 1. A rope or leading to the side of the vessel.
- 2. A rope used to steady a boom.
- To change from one to the other away from the wind, with the of the vessel turning through the wind. See also going about and .
- gypsy winch
- A type or component of an anchor winch. The "gypsy" or "gypsy wheel" engages the anchor chain.
- half-breadth plan
- In shipbuilding, an elevation of the lines of a ship, viewed from above and divided lengthwise.
- Originally, ropes used for hoisting a with a attached; today, a line used to raise the head of any sail.
- Canvas sheets, slung from the deckhead in , in which seamen slept. "Lash up and stow" was a piped command to tie up hammocks and stow them (typically) in racks inboard of the ship's side so as to protect the crew from splinters from shot and provide a ready means of preventing flooding caused by damage.
- Articles that normally are indispensable aboard ship but at certain times are in the way.
- To furl a .
- 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 on a sailing ship (originally "hand over hand").
- 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 on an aircraft carrier, usually beneath the flight deck and intended for use as a hangar in servicing and storing aircraft.
- 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.
- harbour of refuge
- An artificial harbour constructed on a coast without a to provide shelter for small vessels.
- A place where ships or smaller craft may shelter from the weather, are unloaded/loaded, or stored. Harbours can be man-made or natural.
- harbour dues
- The fees charged by the owners or operators of a harbour to those vessels using the harbour. Under British legislation, the person in charge of a vessel must report to the harbourmaster within 24 hours of arrival in a port where harbour dues are payable.
- A person in charge of a harbour, with powers including the collection of the harbour dues, instructing the masters of vessels where to moor, and overall safety within the area of the harbour, often including pilotage and navigational aids. In most countries the powers of a harbour master are laid down by legislation, and can be quite extensive.
- A section of otherwise muddy shoreline suitable for mooring or hauling out.
- See lee-oh.
- harden in
- To haul in the sheet and tighten the sails.
- harden up
- To turn towards the wind; to 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.
- A hard and long-lasting dry biscuit, used as food on long journeys. Also called a "ship's biscuit".
- 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.
- 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.
- The shaft or hole in the side of a vessel's bow through which the anchor chain passes. "In through the hawsepipe" describes someone with experience and savvy.
- An informal term for an officer of a who began their career as an unlicensed merchant seaman, and so did not attend a traditional maritime academy to earn their officer's licence. See also before the mast.
- A large cable or rope used for mooring or towing a vessel.
- 1. The forwardmost or uppermost portion of the ship.
- 2. The forwardmost or uppermost portion of any individual part of the ship, e.g. , beakhead, , etc.
- 3. The top edge of a sail.
- 4. The toilet or latrine of a vessel, which in sailing ships usually projected from the bow 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.
- 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 rope
- 1. The mooring rope that goes from the bow of a vessel to a point on a jetty a distance ahead of the bows.
- 2. Part of the bolt rope, at the head of a , running from the to the .
- head sea
- A sea in which waves are directly opposing the motion of the ship, or approaching within 15° of ahead.
- 1. Jibs and staysails set between the bowsprit and the fore 
- 2. Sometimes refers to the square sails on the fore-mast of a square rigged vessel. 
- Stays between the bowsprit and the foremost mast. 
- A change in the wind direction that 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.
- The direction in which the nose of a vessel is pointing (which is not necessarily the same as the direction in which the vessel is actually moving).
- Any set in front of the most forward . A sailing vessel may have one or more headsails. A headsail may be hanked to a stay, or may be set flying, with the luff being kept taut by the tension of the halyard. Where several headsails are set, a complex arrangement might be termed (from the front and top) flying jib, outer jib, inner jib, and (fore) staysail; less complex would be jib and 
- The laced to the head of the .
- A vessel's transient, vertical, up-and-down motion.
- heave down
- To turn a ship on its side (for cleaning), a process which is also known as careening.
- Heave ho!
- An exclamation sailors make when pulling forcefully on a rope.
- heave to
- See hove to.
- heavy weather
- A combination of high winds and rough seas that may be dangerous for a ship or boat, sometimes requiring changes to a passage plan (such as a precautionary diversion to a safe harbour), heaving to, running under bare poles, or other similar survival strategies.
- 1. The lean caused by the wind's force on the of a sailing vessel.
- 2. The inclination or canting of a vessel to one side or the other from the vertical as she maneuvers, e.g. "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.
- 1. A ship's steering mechanism, such as a or .
- 2. The wheel and/or area.
- 3. (v.) To take over the steering of a vessel.
- A member of the crew who is responsible for steering the 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 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.
- A knot used to tie a rope or line to a fixed object. See also bend.
- hobby horsing
- Harmonic pitching of a vessel forward and backward.
- 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.
- 3. A semi-permanent bend in a ship's keel, especially in wooden-hulled ships, caused over time by the ship's center being more buoyant than her bow or .
- hog frame
- A heavy wooden truss fitted lengthwise along each side of a large American steamboat, secured to the hull and rising above deck just outside the , to provide support for the hull and prevent hogging. Similar in appearance and function to a truss bridge. See also king post.
- Hog Islander
- Slang term used for Design 1022 cargo ships and Design 1024 constructed at Hog Island in Philadelphia, Pennsylvania, to address shortfalls in the United States during World War I. Completed too late for World War I, Hog Islanders saw United States Navy and United States Merchant Marine service prior to and during World War II.
- 1. A condition in which the hull of a vessel bends upward such that the ends of the keel are lower than the middle. Hogging can occur when the peak of a wave is amidships or during loading or unloading of a vessel and can damage her or even break her in half. Contrast .
- 2. A permanent distortion of the hull in the same manner as above, 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.
- hogging line
- A line passed under a ship from side to side to pull a collision mat into place over a leak. Also a line passed under a ship from side to side used as a reference to indicate position of a frame during underwater inspections.
- The height of a fore-and-aft-rigged sail as measured next to the or .
- The lower part of the interior of a ship's hull, especially when considered as storage space, as for cargo. In earlier use, the term referred to all interior spaces below the ; in later merchant vessels it extended up through the decks to the underside of the .
- A gap in the coverage of newly applied paint, slush, tar, or another preservative.
- A chunk of sandstone used to scrub a ship's 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 at which a vessel is based. Often confused with the ship's , which is the port listed in the vessel's registration documents and lettered on her but which may differ from her home port. In the cruise ship industry, the term "home port" is often incorrectly used to refer to a ship's port of departure.
- homeward bounder
- A slang term for a sail repair, especially one done with large herringbone stitches.
- Wooden or metal hoops used to secure the topmast so it can be speedily raised or lowered. to the
- A sound signal that uses electricity or compressed air to vibrate a disc diaphragm.
- A type of dance.
- Shaped ends to the chocks where the main horse is bolted.
- horn timber
- A fore-and-aft structural member of the hull sloping up and backwards from the keel to support the counter.
- 1. A metal bar (sometimes a shaped aluminium extrusion), running athwartships, to which a traveller that slides along the horse or is adjusted to be fixed in one position on it. Commonly used for a , but also seen with some headsails, particularly a fitted with a boom. is attached with a
- 2. Sand lying mid-channel.
- 3. (v.) To move or adjust a sail by manual force (i.e. directly with the hands) rather than by using running .
- 4. (v.) A term used since the end of the 17th century for the action of a strong, favorable current on a sailing vessel allowing her to make good progress despite insufficient wind for sailing; the vessel is considered to be horsed by the current, riding it in the way a human rides a horse.
- horse latitudes
- The latitudes between 30 and 35 degrees in the Northern Hemisphere and between 30 and 35 degrees in the Southern Hemisphere in which weather patterns often result in sailing vessels being becalmed in mid-ocean.
- hospital ship
- A ship designated and equipped to serve primarily as a floating medical healthcare facility or hospital, usually operated by military forces such as navies for use in or near war zones, or for the support of disaster relief and other humanitarian operations.
- Attachments of to .
- hotel load
- The electrical load for all non-propulsion systems on a ship, including lighting, climate control, and services used by the crew and passengers.
- hove to
- 1. In a sailing vessel, stopping her by backing some of the sails and lashing the helm to leeward. In a fore-and-aft-rigged , this involves backing the headsail and allowing the to fill somewhat (the precise arrangement varies from one vessel to another). The vessel will gradually drift to leeward, with the speed of the drift depending on the vessel's design.
- 2. In a powered vessel, stopping her by stopping her engines.
- 1. Someone who does Deal boatmen. work, such as that done by
- 2. An additional crewman who assists getting a vessel in and out of harbour. See also huffler (regional usage of these words varies substantially, with strongly held views on the differences).
- how's your head?
- A question asked of the helmsman to report the vessel's course at that moment. The actual course may differ from the course to steer that has been ordered.
- 1. A cutter-rigged craft, having a pole masted with a boomless gaff and a steeved-up bowsprit. Hoys were square, swim-headed Thames estuary barges of 40 to 150 tons burthen.
- 2. A barge making regular passages on a fixed route with mixed third-party cargoes. Also passage barge or goods barge.
- Additional crew taken on to enter harbour or navigate in confined waters, particularly applying to Thames barges. See also hoveller.
- 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 still afloat and continues to serve a useful function, such as providing living, office, training, storage, or prison space.
- 2. (v.) To convert a ship into a hulk.
- 3. A ship that has been launched but not completed.
- 4. An abandoned or shell of a ship.
- The shell and framework of the basic flotation-oriented part of a ship.
- hull speed
- The maximum efficient speed of a displacement-hulled vessel.
- Of a vessel when only her upper parts (e.g. funnel, , and ) are visible on the horizon but her hull remains below the horizon. Contrast hull-up.
- Of a vessel when her hull as well as her upper parts (e.g., funnel, , and ) are visible on the horizon. Contrast hull-down.
- A boat with wing-like foils mounted on struts below the hull, lifting the hull entirely out of the water at speed and therefore greatly reducing water resistance.
- A fast motorboat with a hull shaped so that at speed lift instead of buoyancy. forces support the boat′s weight, rather than simple buoyancy. A hydroplane moving at speed thus relies on the water for
- A special-purpose ship or boat designed to move and navigate through ice-covered waters.
- 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 upon contact with the ship. If the weight of the ice becomes too great, the ship will become top-heavy and capsize.
- Members of a not required to serve watches. In general, these were specialist tradesmen such as the carpenter and the sailmaker.
- in ballast
- (of a vessel) Having only ballast, and no cargo, as a load.
- in irons
- When a sailing vessel has lost its forward momentum while heading into the wind, rendering it unable to steer.
- in ordinary
- An 18th- and 19th-century term originally used to refer to a naval vessel that is 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.
- 1. Situated within a vessel.
- 2. Situated within a vessel and positioned close (or closer relative to another object) to her centerline.
- 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 by a shaft protruding through the . Generally used on larger vessels. See also and .
- inboard-outboard drive system
- See .
- Inglefield clip
- A type of clip for attaching a flag to a flag halyard.
- 1. Near (especially in sight of) or toward the shore.
- 2. (of a wind) Blowing from the sea to the land.
- A term used by the British East India Company in the seventeenth century for a merchant ship operating in violation of the company's monopoly over trade between England (later the United Kingdom) and ports east of the Cape of Good Hope. If caught, an "interloper" and her cargo could be confiscated, and her crew faced harsh penalties.
- Iron Mike
- A slang term for autopilot.
- iron topsail
- An auxiliary motor on a .
- iron wind
- What sailors call inboard engines.
- 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).
- The superstructure of an aircraft carrier that extends above the flight deck. A carrier that lacks one is said to be flush-decked.
- 1. A . Also jack tar or just tar.
- 2. (jack (flag)) A national or other official flag flown on a short jackstaff at the bow of a vessel indicating nationality or subordination to a navy or other particular seagoing service or to a government department or subnational government (such as a state or province), or to indicate membership in a . Typically, crew members spoke of the jack as if it were a member of the crew. A jack contrasts with an ensign, which is a flag with a generally similar purpose flown from the vessel′s . Typically, vessels fly a jack while in port and an ensign while at sea (in daylight hours).
- 3. Informally, any flag flown by a ship.
- A sailing ship with three or more , of which the foremast is and the main is partially ( , , etc.) and partially fore-and-aft-rigged (course). The is fore-and-aft-rigged.
- jack dusty
- A naval stores clerk.
- jack tar
- A sailor dressed in "square rig" with square collar. Formerly with a tarred pigtail.
- On a , a deck lifeline of rope or (preferably) flat tape, running fore and aft, to which the crew can clip their harnesses for safety. Sometimes called a jackstay, though this is a misnomer as a jackline is a line rather than a . The line must be very strong to take the weight of all crew clipped to it.
- A small vertical pole on the bow of a vessel upon which is flown its flag, or jack. The jackstaff was introduced in the 18th century.
- 1. A rope, bar, or batten running along a ship's , to which is attached the head of a square sail.
- 2. A for racing or cruising vessels used to steady the against the strain of the gaff.
- 3. A cable between two ships or from a ship to a fixed point that supports a load during transfer of personnel or materiel along the cable.
- 4. On a , a deck lifeline of rope or (preferably) flat tape may be called a jackstay, though this is a misnomer as a jackstay is a stay rather than a line.
- Jacob's ladder
- 1. A flexible hanging ladder consisting of vertical ropes or chains supporting horizontal rungs, used to allow access over the side of a ship, either to transfer between the ship and another vessel alongside it or to perform maintenance tasks along the side of the ship. Sometimes mistakenly referred to as a , which differs from a Jacob′s ladder in its use of spreaders and in terms of specific regulations governing step size and step spacing.
- 2. A vertical ladder from the ratlines found on ships, used to get around the while climbing between the lower mast and the topmast.
- A man-made pier in a marina or open water, typically made of wood or rocks and rising several feet above high tide in order to create a breakwater, shelter, channel, erosion control, or other function.
- Floating debris ejected from a ship. See also flotsam.
- A triangular headsail at the front of a sailing vessel. The is attached to the bow or to a bowsprit. May be the only headsail, or one of several – in which case the jib is set forward of the fore staysail. A large jib that overlaps the is called a genoa or genny.
- jib top
- A high-clewed overlapping headsail for beam reaching in medium to strong winds
- A used to extend the bowsprit.
- See gybe.
- See gybe-oh.
- The fourth on a ship, or the aftmost mast where it is smallest on vessels of less than four masts.
- 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 of planking. The feather end is cut off to produce a . The joggle and nib in this case is made wide enough to allow a caulking iron to enter the seam.
- Traditional Royal Navy nickname for the Royal Marines.
- jolly boat
- A type of used to ferry crew and stores.
- A person (either a sailor or a passenger) who carries a jinx, one whose presence on board brings bad luck and endangers the ship.
- Jonah's lift
- The throwing overboard of a man considered to be a Jonah, almost always in the dark of night.
- 1. Old cordage past its useful service life as lines aboard a ship. The strands of old junk were teased apart in a process known as "picking ".
- 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 a temporary and/or and the name of the resulting rig. A jury rig would be built at sea when the original rig was damaged, and then used to sail to a harbor or other safe place for permanent repairs. Also used as a general term for a temporary repair, hence "jury rudder", "jury tiller", etc.
- A type of Palau. native to
- K BO Line
- A line or mark on the aft end of a ship indicating the true centerline of the .
- A type of relatively light anchor.
- A technique for moving or turning a ship by using a kedge. The kedge anchor may be dropped while in motion to create a pivot and thus perform a sharp turn. It may also be carried away from the ship in a smaller boat, dropped, and then weighed, pulling the ship forward.
- The principal central longitudinal structural member of a hull, positioned at or close to the lowest point of the hull. Where the keel protrudes below the surface of the hull, it provides hydrodynamic resistance to the lateral forces that give rise to leeway. A ballast keel of (typically) lead or cast iron may be fastened underneath the structural keel in sailing vessels to provide stability and usually also additional hydrodynamic resistance effects. See also bilge keel.
- A type of maritime punishment by which one is dragged under the keel of a ship.
- A baulk of timber or a steel girder immediately above the keel that forms the backbone of a wooden ship. A chine keelson of more modest proportions is fitted at the junction of the floors and frames.
- See anchor sentinel.
- Weights, usually pig iron, used as permanent, high-density ballast.
- A two-masted fore-and-aft-rigged sailboat with the aft mast (the ) mounted ( ) afore the .
- 1. A small anchor.
- 2. A promoted to the first step of the promotion ladder in the British Royal Navy. A fouled anchor is the substantive badge of non-commissioned officers, signifying that the wearer is an able seaman skilled to cope with the awkward job of dealing with a fouled killick.
- kicking strap
- 1. A rope, tackle, or hydraulic ram running from the mast at or just above deck level to a point partway along the boom of a yacht's or . 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.
- 2. A chain rigged from to that is tight at anchor, stopping the rudder from kicking and reducing pressure on its gudgeons.
- 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.
- king post
- 1. On an American wooden-hulled steamboat, a type of suspension bridge; usually used in conjunction with a hog frame. or located along the vessel's centerline from which heavy chains (and later cables) were suspended to support the weight of the hull and provide stiffening, in much the same manner as the cables on a
- 2. On a cargo ship, a strong vertical post from which a derrick or boom is suspended.
- Kingston valve
- A type of designed so that the water pressure from the sea keeps it closed under normal operating conditions, but can be opened from the inside of the ship, allowing seawater to enter internal fuel, water, or ballast tanks. Kingston valves can be opened to a ship.
- kissing the gunner's daughter
- Bending over the barrel of a gun for punitive beating with a cane or cat o' nine tails.
- kitchen rudder
- A hinged cowling around a fixed , allowing the drive to be directed to the side or forwards in order to manoeuvre the vessel.
- A .
- 1. A structural element connecting two parts roughly at right angles, e.g. deck beams to frames.
- 2. A vertical rubber fender used on or , sometimes shaped like a human leg bent slightly at the knee.
- 1. A mitred backing timber that extends the after line of the in the 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.
- See header.
- The condition of a sailboat being pushed abruptly over on its side, i.e. to horizontal or "on its beam-ends", with the parallel to the water surface.
- A unit of speed equivalent to 1 nautical mile (1.8520 km; 1.1508 mi) per hour. Originally the speed of a moving vessel was measured by paying out a line from the ; the line was tied into a knot every 47 feet 3 inches (14.40 m), and the number of knots paid 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. Both vessel speed and wind speed are commonly reported in knots.
- know the ropes
- A sailor who knows the ropes can identify all the many ropes used in working a sailing vessel. On a square rigged ship, there would typically be more than 130 named ropes in the running rigging which are made fast at deck level – the majority of these are duplicated on both the port and starboard sides, so doubling that count. In order to know the ropes, a sailor must first learn the ropes. There were conventions with the positioning of all the many ropes belayed at deck level on a square-rigged ship, so a newly signed-on hand would quickly know where to find a particular rope on a strange ship.
- To attach a to a by passing a rope through eyelet holes and around the spar or its jackstay.
- On board a ship, all "stairs" are called ladders, except for literal staircases aboard passenger ships. Most "stairs" on a ship are extremely narrow and nearly vertical, hence the name.
- Cargo that has been thrown overboard and buoyed so it can be found later, sunk to the seabed.
- laid up
- To be placed in or . The latter usage in modern times refers to a specific set of procedures used by the United States Navy to preserve ships in good condition.
- Great Lakes slang for a vessel that spends all of her time on any of the five Great Lakes.
- A Great Lakes term for the general cargo and passenger trade between settlements on the Great Lakes during the 19th and early 20th centuries. Lakeshoring usually was conducted by of 50 to 60 feet (15 to 18 m) in length, sometimes referred to as lakeshoring schooners.
- land lubber
- A person unfamiliar with being on the sea or with the workings of a seafaring vessel.
- An object ashore that is visible from sea and sufficiently distinct such that it is marked on nautical charts for the purpose of fixing position while at sea.
- A military rank for a naval recruit, used in the United Kingdom in the 18th century and the first half of the 19th century and in the United States in the 19th and early 20th centuries.
- 1. Another name for canister shot.
- 2. Solid shot suitable for damaging rigging.
- lang's lay
- Rope in which the lay of the strands is on the same hand as the lay of the constituents of the strands.
- A light that suspends a small item to prevent loss or is used to operate something by pulling on it.
- An obsolete term for the left side of a ship. Derived from "lay-board", which provided access between a ship and a when ships normally docked with the left side to the wharf. Later replaced by "port side" or " ", to avoid confusion with .
- See by and large.
- lateen sail
- A triangular, sometimes quadrilateral, fore-and-aft set on a long mounted at an angle to the .
- 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).
- lattice mast
- A type of observation mast constructed with a hyperboloid structure using an array of thin columns at angles, crossing each other in a double-helical spiral configuration. Lattice masts were most common aboard major United States Navy warships in the early 20th century, particularly on dreadnought battleships and armored cruisers; they were largely replaced by during the 1920s and 1930s.
- 1. The largest carried by a warship – usually an open boat and, in more recent times, fitted with an engine. Historically, fitted both to be rowed or sailed.
- 2. In modern usage, a large motorboat; e.g. a harbourmaster's launch.
- 3. An elegant power boat of traditional character with a displacement hull; e.g. a .
- 4. To dispatch a newly built ship down a , usually with ceremony, prior to fitting-out and commissioning.
- 5. To put into the water any boat that is stored or temporarily kept out of the water; e.g. "launch the lifeboat" or "launch a dinghy".
- 1. To come and go, used in giving orders to the crew, e.g. "lay forward" or "lay aloft", respectively indicating that the crew should move to the forward part of the ship or take up positions aloft.
- 2. To direct the course of a vessel.
- 3. (v) To twist the strands of a together. (n) The direction of twist in cordage made from twisted strands
- 4. To travel in a direction which will reach or pass just upwind of a mark, buoy, or harbor, e.g. "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.
- lay to
- To bring a vessel into the wind and hold her stationary. A vessel doing this is said to be laying to.
- laying down
- Laying the keel of a ship in a , and thereby beginning her construction. The age of a ship is often indicated by giving the date it was laid down.
- The amount of time stipulated in a for a vessel to be loaded or unloaded. If a vessel is loaded or unloaded in less than the laytime, the shipowner may be required to pay despatch to the charter party. If the loading or unloading takes longer than the laytime, the charter party may be required to pay demurrage to the shipowner.
- 1. A small stowage locker at the aft end of a boat.
- 2. A ship or building used for the 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
- A network of cordage rigged to a point on the 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.
- lazy line
- A line used for stern-to mooring attached to a floating pontoon or harbor wall which leads back to a seabed mooring.
- The after edge of a sail.
- 1. A plummet or mass of lead attached to a line, used in depth at sea.
- 2. In former usage, to estimate velocity in knots.
- 3. The path or route of a line (cordage).
- 4. See: Lead (sea ice): Large fracture in sea ice creating a navigable waterway.
- An instrument used in navigation to ; the line attached to a lead.
- A sailor who takes with a lead, measuring the depth of the water.
- A unit of length used to measure distances, normally equal to three , but varies by nationality.
- learn the ropes
- To be trained in the identification and proper use of the many various used on a sailing ship. An apprentice sailor, especially on a ship, needs to know which rope of the many that are belayed at deck level does which job. A small square sail will have, at a minimum, two , two clewlines, several buntlines, and two braces, and may also have a halyard. A single may have up to five square sails. To do his job, a sailor must be able to identify each rope from all the many options – and in the dark. or hauling the wrong one may not only be inefficient but also potentially dangerous. Once proficient in these tasks, a sailor is said to "know the ropes".
- lee helm
- The tendency of a sailboat to turn to leeward in a strong wind when there is no change in the 's position. This is the opposite of and is the result of a dynamically unbalanced condition. See also center of lateral resistance.
- lee side
- The side of a ship that is sheltered from the wind; i.e. the side that is downwind, or in the direction toward which the wind is blowing. Contrast or .
- lee shore
- A shore downwind of a ship. A ship that cannot sail well to risks being blown onto a lee shore and grounded.
- A large fan-shaped wooden board or fin mounted in pairs on the side of a boat. They can be lowered on the lee side of the ship to reduce leeway (similarly to a centerboard on a dinghy).
- leeboard irons
- The iron bars that run from the case to the head of each leeboard, which they support.
- leeboard pendant
- A wire connecting the fan of the leeboard to a winch on the barges quarter. They control the fall of the leeboard.
- The aft or trailing edge of a fore-and-aft sail, the leeward edge of a , or a vertical edge of a square sail. The leech is susceptible to twist, which is controlled by the boom vang, , and, if rigged with one, the gaff vang.
- A command to come about ( through the wind) on a sailing boat. The response by the helmsman to indicate the order has been carried out, is "helm's alee"
- (pronounced // in nautical use) In the direction toward which the wind is blowing. Contrast .
- The amount that a ship is blown leeward by the wind. Also the amount of open free sailing space available to the lee side of a vessel before encountering hazards. See also .
- In navigation, a segment of a between two waypoints.
- length between perpendiculars
- The length of a vessel along the from the forward surface of the or main bow perpendicular member, to the after surface of the or main perpendicular member. The measure generally allows for a reasonable estimate of the vessel's carrying capacity, as it excludes the small, often unusable volume contained in her overhanging ends.
- length overall (LOA)
- The maximum length of a vessel's hull measured parallel to the , usually measured on the hull alone, and including overhanging ends that extend beyond the main bow and main 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
- An official warrant granted to a condoning specific acts of against a specific target as a redress for grievances.
- A relatively short period when a sailor is allowed ashore for recreation. See also .
- licensed ship
- A term used by the British East India Company from the 17th to the 19th centuries for merchant ships not under charter to it which it nevertheless permitted under a license issued by the company to trade between England (later the United Kingdom) and ports east of the Cape of Good Hope, a trade over which the company otherwise held a strict monopoly. The company placed strict controls on what ports a licensed ship could visit and what kinds of trade it could engage in. A licensed ship that violated these rules became an interloper and faced harsh penalties if caught.
- lie to
- To arrange a ship's so that they counteract each other. A ship in this condition or in the process of achieving this condition is said to be lying to.
- A portable or wearable device such as a buoyant ring or inflatable jacket designed to keep a person afloat in the water.
- 1. (shipboard lifeboat) A small boat 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) A small boat usually launched from shore and used to rescue people from the water or from vessels in difficulty.
- An inflatable, sometimes covered raft used in the event of a vessel being abandoned or in the evacuation of an aircraft after a water landing.
- 1. A rope that supports a spar on a sailing vessel. Examples include the topping lift on the boom of a fore and aft rigged sail, or the lifts on the yard of a square rigged sail, which can adjust the yard to the horizontal or cock-bill the yard to get it out of the way when unloading cargo or alongside another vessel. 
- 2. An enabling shift in the direction of the wind that allows a close-hauled sailing ship to from its current course to a more favorable one. This is the opposite of a header.
- light irons
- Iron bars mounted near the main that support the navigation lights.
- light screens
- Boards on which the navigation lights are hooked and which shield the direction that the red or green light shows.
- A flat-bottomed barge used to transfer goods and passengers to and from moored ships, traditionally unpowered and moved and steered using "sweeps" (long ), with their motive power provided by water currents.
- The process of transferring cargo from one vessel to another in order to reduce the draft of the first vessel, typically done to allow a vessel to enter a with limited depth or to help free a grounded vessel.
- 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.
- limber hole
- A channel cut in the underside of a frame, close to the keel, to allow bilge water to drain away to the pump well, rather than being trapped between each set of frames.
- limber board
- A part of the ceiling alongside the keelson, easily removable for cleaning out the limber holes.
- The correct nautical term for the majority of the cordage or "ropes" used on a vessel. An individual line will always have a more specific name (e.g. the halyard) that specifies its use.
- line astern
- In naval warfare, a line of battle formed behind a flagship.
- 1. During the Age of Sail, a , or a major capable of taking its place in the main battle line of fighting ships.
- 2. Any cargo or passenger ship running scheduled service along a specific route with published ferries and other vessels engaged in short-sea trading. When referring to cargo ships, "liner" contrasts with " ", 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, " " refers to ships providing scheduled transportation between regular ports of call, but excludes cruise ships, which voyage for recreational purposes and not primarily as a form of transportation between ports. , excluding
- The degree or angle to which a vessel leans or tilts to one side, on the axos, at equilibrium, i.e. with no external forces acting upon it. The term typically refers to a lean caused by flooding or improperly loaded or shifted cargo, as opposed to heeling, which is a consequence of external forces. A vessel with such a lean is said to be listing. Compare loll.
- A short length of with an eye, used to hold another rope in position.
- loaded to the gunwales
- Literally, having cargo loaded as high as the ship's rail. The term is also used as an idiom meaning "extremely drunk".
- In boat construction, a drafting technique used to convert a scaled drawing to full size.
- 1. A bollard mounted in the whaleboat for snubbing the whale line as a harpooned whale swam away from the boat.: 144 of a
- 2. An iron ball attached to a long handle, used for driving caulking into seams and (occasionally) in a fight; hence the expression "at loggerheads".
- A list to either side caused by inadequate transverse stability in the upright condition.
- Long Forties
- An area of the northern North Sea which is fairly consistently 40 fathoms (240 feet; 73 metres) deep. On nautical charts with depths indicated in fathoms, it appears as a long area with many "40" notations.
- long stay
- The relative slackness of an anchor chain; this term means taut and extended.
- 1. In the Age of Sail, a double-banked open boat carried by a sailing ship, rowed by eight or ten oarsmen, two per , 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.
- A fishing vessel rigged for longline fishing ("longlining").
- 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.
- A member of the crew specifically assigned to watch surrounding waters for other vessels, land, objects in the water, hazards, threats, etc. Lookouts usually have duty stations high on a vessel's superstructure, in a specially designed or crow's nest, or in her , in order to enhance their field of view.
- loose cannon
- An irresponsible and reckless individual whose behavior (either intentionally or unintentionally) endangers the group he or she belongs to. The term refers to a hypothetical literal loose cannon which, 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.
- A fore-and-aft 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 who are not officers, often used in the plural (e.g. "the lower decks").
- The lower brails on the .
- lubber's hole
- A port cut into the bottom of a or (crow's-nest) allowing easy entry and exit. It was considered "un-seamanlike" to use this method rather than going over the side from the , and few sailors would risk the scorn of their shipmates by doing so (at least if there were witnesses). In practice, it is often actually quicker and easier for a fit sailor to climb outside the masthead than through the lubber's hole.
- lubber's line
- A line or mark inside or on a compass case or binnacle indicating the direction of the ship's head.
- lucky bag
- 1. A locker or compartment for storage of unclaimed articles.
- 2. U.S. Naval Academy yearbook.
- 1. The forward edge of a sail.
- 2. The fullest or roundest part of a ship's bow.
- 3. To point a sailing vessel closer to the wind.
- luff and touch her
- To bring a vessel so close to the wind that the sails shake.
- luff barge
- An 18th-century term for a sailing barge with a rounded bow and not a .
- luff perpendicular (LP)
- The shortest distance between the clew and the luff, which is a perpendicular line from the luff to the clew. Commonly given as a percentage of the "J" measurement.
- luff up
- To steer a sailing vessel more towards the direction of the wind until the pressure is eased on the .
- 1. (of a sailing vessel) Being steered far enough to that the sail is no longer completely filled with wind; in such a state, the luff of a fore-and-aft sail begins to flap first.
- 2. Loosening a so far past optimal trim that the sail no longer completely fills with wind.
- 3. The flapping of a sail from having no wind at all.
- lumber hooker
- A Great Lakes ship designed to simultaneously carry her own deck load of lumber and to tow one or two barges. The barges were big old stripped of their and running gear to carry large cargoes of lumber.
- A sailing vessel with lug sails set on one, two, or more and perhaps lug , widely used as traditional fishing boats, particularly off the coasts of France, England, and Scotland; also used as privateers and smugglers.
- lug sail
- A four-sided fore-and-aft supported by a along the top that is fixed to the at a point some distance from the center of the spar. A dipping lug had to be moved to the other side of the mast when (in larger vessels, by partially lowering the sail and hauling down either the peak or the throat to move the across). A standing lug can be used on either tack in the same position. It was common for British fishing luggers to have a dipping lug on the foremast and a standing lug on the .
- lying ahull
- Waiting out a storm by dousing all and simply letting the boat drift.
- lying to
- See lie to.
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