Useful Nautical Terms

The following is a list of mostly historical however usually still valid nautical terms. This list has been reprinted without permission from the Patrick O'Brian Page. For those of you sailing nuts who have not heard of the Aubrey books, put down your mouse, back away from the screen and run (don't walk) to the nearest bookstore and pick up Master and Commander. It is the 1st book of (currently) 19. You will not be disappointed.


Abaft the Beam Behind a horizontal line drawn through the middle of the ship, at right angles to the keel.

Afterguard The seamen who are stationed on the poop and quarter deck of the vessel, to attend and work the after sails etc.

Afternoon Watch The watch from noon until 4 p.m. The nautical day begins at noon.

Anchor .

Aweather Toward the weather or windward side of the vessel. The opposite of Alee.

Back (to) To brace the weather yardarm in so that the wind acts on the forward part of the sail, pressing it back.

Backstays Ropes forming part of the standing rigging. They stretch from mastheads and tend aft from the masts. They serve to support the masts against forward pull and are named according to the mast they support.

Barge A long, narrow, light boat, employed to carry the principal sea officers, such as admirals and captains of ships of war, to shore. They were very unfit for open sea.

Bark (also Barque) In Aubrey's time barque meant barque-rigged, i.e. fore and aft on the mizzen.

Beam The lumbers that run horizontally across the deck from side to side.

Beam-Ends A vessel is on her beam-ends when listed to an angle where her beams are almost vertical, and her righting power insufficient to return her to the upright.

Bear away To put the helm up and run off to leeward. To put before the wind.

Before the mast An expression used to describe the station of seamen who had their accommodations in the forward part of the ship, as distinguished from officers who were berthed aft. Thus a man before the mast meant a common sailor and not an officer.

Binnacle A wooden case or box, which contained compasses, log-glasses, watch-glasses and lights to show the compass at night. There were always two binnacles on the deck of a ship of war, one being designed for the man who steered, the other for the person who superintended the steerage, whose office was called conning.

Boom See under brig .

Blue Peter A blue signal flag with white square in the center, hoisted on the foremast to indicate a vessel is ready to sail. It was a recall to the crew "that they repair on board" and for shoresiders to conclude any business they had with the vessel.

Bowline A rope fastened near the middle of the leech, or perpendicular edge of the square sails, by three or four subordinate parts called bridles. It was only used when the wind was so unfavorable that the sails had to be braced sideways, or close hauled to the wind: In this situation the bowlines were employed to keep the weather, or windward, edges of the principal sails tight forward and steady, without which they would always be shivering, and rendered incapable of service.

Bowsprit A large spar which projects forward from the stem of a vessel. Its purpose is to extend the head sails, thereby counteracting the effect of the after sails and keeping the sail plan balanced. It is also one of the main supporters of the foremast, which is fastened to it by stays.

Box Hauling A method of bringing a close-hauled ship around upon the other tack by throwing the head sails aback, if it refuses to tack and there is no room to wear.

Brace A rope attached to the end of a yard to haul it aft, rotating the sail.

Brig A two-masted vessel, mostly square-rigged, but with a fore-and-aft mainsail.

Bring by the lee To incline so rapidly to leeward of the course, when the ship sails large, as to bring the lee-side unexpectedly to windward; and by laying all the sails aback expose her to the danger of upsetting.

Burgoo Various definitions. It was not considered a fancy dish.

  1. Oatmeal porridge
  2. hard tack and molasses

By and Large See full and by .

Cat (to) To heave the ring of a stocked anchor to the cat head.

Catheads Two strong short beams of timber, projecting almost horizontally over the ships bows, on each side of the bowsprit.

Clew (to) To haul a square sail up to a yard previous to furling by means of clew lines.

Clew lines Lines running from the corner of the sail, known as the clew, to the yardarm and down to the deck.

Close hauled See under Bowline .

Club haul A method of tacking, by letting go the lee anchor as soon as the wind is out of the sails, which brings the ship's head to wind, and as soon as she pays off the cable is cut and the sails trimmed. Only resorted to in perilous situations, and when it is expected the ship will miss stays.

Cockpit Compartment on a warship where the wounded and ill were tended. Usage now extends to any well or sunken space in the afterdeck of a small craft, with a coaming of about 6 inches.

Condemnation Confiscation of a vessel or her cargo, or both, as decreed by a prize court of the belligerent.

Dead reckoning The process by which the position of the ship at any moment is found, without any observation of the sun or stars, by applying to the last well-determined position the run that has been made since, using for this purpose the ship's course indicated by its compass, the distance indicated by the log, and taking into account drift and leeway.

Depth measurement See marks and deeps .

Dog Watch One of the two two-hour watches between 4 and 8 p.m. The dog watches permit a shift in the order of the watch every 24 hours so that the same men will not have the same watch every night.

Driver Sometimes used for the spanker, sometimes for a studdingsail-like addition to the spanker, but in either case, the aftermost sail in a ship.

First Watch The four-hour watch between 8 p.m. and midnight.

Forecastle (fo'c's'l) The raised platform at the bow of a ship, often armored, for musketeers. In some ships it was the location, ergo the name, of the crew's quarters.

Forenoon Watch A name given to the watch from 8 a.m. to noon.

Fore-and-Aft Sail A sail which attaches forward to a vertical mast and at the bottom usually to a horizontal boom. It may also be lifted up at the peak with a gaff. Instead of a square sail which always is set perpendicular to the wind, fore-and-aft sails allow a boat to sail much closer to the direction from where the wind is blowing.

Forepeak See peak .

Free a ship Running free when it is not obliged to brace its yards sharp up (move them closer to a fore-and-aft position). The converse of close-hauled.

Full and By Said of a sailing vessel when all sails are drawing full and the course steered is as close to the wind as possible. Sometimes known as sailing by and large.

Futtock A name given to the curved pieces of timber which compose the frame timbers. They are named according to their location: first futtock, second futtock, etc.

Gaff A spar which holds the peak of a gaff-rigged fore-and-aft sail. Instead of a triangle shaped sail with the peak being at the top of the mast, a gaff-rigged sail is four sided.

Gammoning The art of binding the rope (and hence its name) which secures the bowsprit to the stem piece and is passed backward and forward in the form of an X over the bowsprit, to enable it to support the stays of the foremast and carry sail in the fore part of the vessel.

Gudgeon (or Goodgeon) One of the several iron lugs (sockets) projecting from the after side of the stern or rudder post to support the rudder. Each gudgeon is bored out to receive the corresponding pintle fastened to the forepart of the rudder, which thus turns as upon hinges. See also pintle.

Halyard The rope used for hoisting or lowering spars, yards, or sails on their respective masts or stays.

Hard tack See ship's biscuit .

Haul off (to) To alter the course of a ship so as to get further away from an object.

Hawse The general region around the ship's head where the hawse-holes, through which the cables pass, are to be found: it also applies to the air and sea somewhat ahead, where the cables would be if the ship were anchored.

Headsails Generic term for all sails which may be set on the bowsprit, or foremast. As opposed to aftersails.

Heel (to) To stoop or incline to either side due to the action of the wind, waves, a greater weight on one side, etc. Usually temporary.

Hollow Sea A condition usually occurring where there is shoaling water or a current setting against the waves. The line from crest to trough makes a sharp angle, and consequently the sea is very dangerous.

Hull The part of the boat which sits in the water. When you take off all of the rigging, masts, bowsprit, and anything being carried by a boat, you are left with the hull.

Hull Down Said of a vessel when it is so far away from the observer that the hull is invisible owing to the convexity of the earth's surface, while the masts are still seen. The opposite of hull up.

Hull Up See hull down .

Jury mast A temporary or makeshift mast set up by the ship's crew to take the place of one which has been lost or carried away.

Keel The part of the hull which sticks down lower in the water below the bottom of the hull to stop a boat from moving sideways. Sailboats want to go in the direction of the wind and it is the keel which stops them from moving sideways so that the forces of the sails can drive the boat forward. Sailboats that don't have keels have a removable piece often called a centerboard.

Kites In general, the highest and lightest sails set above royals, such as skysails, moonsails and stargazers; also royal and topgallant studding sails.

Knee A timber with two arms at right angles or nearly so, used to connect a ship's beams with her sides or timbers.

Knot A vessel's rate of speed, a nautical mile per hour. Measured by running out a stern line (or log line) knotted at measured intervals which bear the same proportion to a mile as half a second does to an hour.


  1. A line to make an object fast or to aid in carrying it
  2. The line by which a sailing ship's shroud is secured to a chainplate.

Larboard The left, or port, side of any craft when facing the bow. Perhaps derived from the 13th century English word laddebord, or loading side; some suggest it goes all the way back to the Norse word hlada bord of the same meaning.

Large To sail large is to run with the sheets eased off when the wind is from abaft the beam and the bowlines are entirely disused so that the sails receive the full effect of the wind. Also known as to sail free.

Lay aloft Order given to the crew to go up into the rigging.

Leeway The lateral movement of a ship to leeward of her course, estimated from the angle formed between the line of the ship's keel and the line which the ship actually describes through the water, as shown by her wake.

Loblolly boy A surgeon's assistant aboard ship. Loblolly, another form of burgoo, was the name for the gruel or porridge usually served to the surgeon's patient in the sickbay.

Lubber's hole The vacant space between the head of the lower mast and the edge of the top (the platform which rests upon the crosstrees at the head of a lower mast), through which those not wanting to use the futtock shrouds could go further aloft.

Luff (to) To bring a vessel's head nearer to the wind, so the sails start to spill wind, by putting the helm down or increasing the sail area toward the stern. Also the order--as in "luff round!" or "luff up!"--to throw the ship's head into the wind in order to tack.

Marks and deeps The divisions used in marking a hand-held lead line at the second, third, fifth, seventh, tenth, thirteenth, fifteenth, seventeenth and twentieth fathoms, each designated by bits of leather are called marks. The intermediate fathoms, estimated by the leadsman, are called deeps.

Marline spike or marling spike A pointed iron pin about 16 inches long, furnished with a round head, used by riggers and seamen to separate the strands of rope when splicing and also as a lever when putting on seizing, marling etc.

Mast A vertical spar to which the fore-and-aft sails and/or yards are attached. It is held up by shrouds on either side and stays fore and aft. It may also carry a crow's nest or other lookouts.

Middle Watch The watch from midnight until 4 a.m., which follows the first watch.

Miss stays (to) To fail in going about from one tack to the other, as a result of which the ship gets its head to the wind, comes to a stand, and begins to fall off on the same tack.

Mizzen The aftermost mast which supports all the after sails.

Morning watch The watch from 4 a.m. to 8 a.m.

Oakum A caulking material used in waterproofing the seams between strakes of planking. It is a mass of strong, pliable tarred rope fibers obtained from scrap rope, which swell when wet. The fibers are soaked in pine tar and loosely bundled together.

Offing Implies out at sea, or at a good distance from the shore, where there is deep water and no need for a pilot to conduct the ship.

Orlop The lower but temporary deck in a ship of war, whereon the cables are usually coiled, the sails deposited, and the several officers' storerooms contained.


  1. The upper aft corner of a square fore-and-aft sail
  2. A compartment in either extreme end of the vessel, bow or stern, referred to as forepeak or afterpeak.

Pinnace Resembles a barge, but is never rowing more than eight oars, whereas a barge never rows less than ten. The pinnace is for the accommodation of lieutenants etc.

Pintle One of several pins or bolts on the forward edge of the rudder frame, by which the rudder is hinged to the gudgeons of the sternpost or rudderpost, around which it pivots. See also gudgeon.

Pitch (to) To plunge with alternate fall and rise of bow and stern, as when a ship passes over waves and into the hollow of the sea.

Points of sailing Sailing points may be defined as the different courses followed by any sailing craft when compared to the direction of the wind. They are named according to the angle between the direction of the wind and the fore-and-aft line of the vessel. When this angle is near 180 degrees the ship is said to be sailing with the wind aft, or before the wind. When it is about 135 degrees it is sailing with the wind on the quarter, or quartering; when about 90 degrees it is running free. When the angle is less than 90 degrees a square-rigged ship is said to be close-hauled, on the wind or by the wind.

Poop The highest and aftermost deck of a ship.

Port See larboard.

Preventer backstay One of a pair of additional backstays set up temporarily leading from the head of a mast to the ship's side where it is set up with a tackle, and carried in strong winds or when under a press of sail.

Quarterdeck A term applied to the afterpart of the upper deck. In naval vessels, that portion of the weather deck which is reserved for the use of the officers.

Ratline One of the small lines traversing the shrouds and forming rope ladders used by seamen for going aloft.

Royals Small square sails, carried next above the main topgallant sail, and used only in light winds because their masts are poorly supported and their position is such that they set with a long leverage and have a tendency to bury the ship and retard her progress in heavier winds.

Sail large, Sail free (to) See large.

Sailing on a bowline Sailing on a wind or close-hauled when the bowlines would be hauled taut.

Sea pie A seaman's dish composed of fish or meat and vegetables in layers between crusts, the number of which determine whether it is a "double-decker" or a "three-decker."

Sheet anchor The largest spare anchor used in a ship, carried in the waist, as far forward as convenient, and kept ready for use in an emergency--the mariner's last refuge.

Sheet home To strain or haul on a sheet until the foot of a sail is as straight and as taut as possible.

Ship biscuit Hard bread, much dried, consisting of flour, water or milk, salt, which does not deteriorate when stored for long periods and therefore is suitable for use on board ship for up to a year after it was baked. Also called hard tack.

Shroud One of a set of strong ropes extending on each side of a masthead to the sides of a ship to support a mast laterally. Shrouds take their name from the spars they support.

Soft tack Seaman's term for leavened bread as distinguished from hard tack or biscuit.

Spar A general term for a round piece of timber, very long in proportion to its diameter, used for masts, yards, booms, gaffs, bowsprits, and so on.

Spritsail A sail attached to a yard which hangs under the bowsprit, and has a large hole at each of its lower corners to evacuate the water which fills its cavity by the surge of the sea when the ship pitches.

Square rig A general term for all rigs where sails are extended by yards attached to the masts in the middle of the ship and trimmed with braces. The theoretical center of effort of the sail plan is situated forward of the center of lateral resistance, or the opposite of that in a fore-and-aft rig, and is done to facilitate paying off in any sudden change of wind and thus to prevent the sails from being taken aback.

Stanchion A pillar of wood or iron used for various purposes in a ship: to support the deck, the quarter rails, the nettings, the awnings etc.

Starboard The right side of any craft when facing the bow. Before the advent of the stern rudder, vessels had their steering oars on the right, or steering board, or starboard side. See also larboard.

Stay A large strong rope employed to support the mast on the fore part, by extending from its upper end towards the fore part of the ship as the shrouds are extended to the right and left and behind it.

Stem A circular piece of timber, into which the two sides of a ship are united at the fore end. The lower end of it is scarfed to the keel, and the bowsprit rests on its upper end.

Strake A range of planks abutting against each other and extending the whole length of the ship.

Strike the Bell Expression used at sea to denote the divisions of the daily time from their being marked by bells which are struck every half hour, the term "bell" being employed aboard ship as "o'clock" is ashore.

Studding sail (stun's'l) A sail on a special spar, extended outboard of a square sail or sails, for added sail area in moderate winds.

Taffrail The upper part of the ship's stern, usually ornamented with carved work or molding.

Taken Aback Said of a vessel's sails when caught suddenly or unexpectedly by the wind in such a way as to press them aft, or so as to impart a tendency to force the ship astern.

Top The semicircular platform which rests upon the crosstrees at the head of a lower mast. It serves to spread the topmast shrouds, so as to form a greater angle to the mast and support it better. Tops are named after the mast to which they belong, e.g. foretop, maintop, mizzentop.

Topgallant A square sail extended above the topsails in the same manner as topsails are extended above the lower yards.

Topmast The spar next above a lower mast and below the topgallant mast.

Voyol A large rope used to unmoor, or heave up the anchors of a ship, by transmitting the effort of the capstan to the cables.

Waist The central part of a ship. The portion of the upper deck between poop and forecastle.

Warp (to) To move a vessel from one place to another in a port, river, or harbor by means of warps (ropes) fastened to buoys, anchors, or some fixed object ashore.

Wear (to) To bring a vessel sailing close-hauled to another tack by putting the helm up and turning her head away from the wind. The opposite of tack.

Weather deck An uncovered deck exposed to the weather. The uppermost continuous deck, exclusive of forecastle, bridge and poop.

Windsail A sort of tube or funnel made of canvas spread by wooden hoops, serving to convey a current of fresh air below deck. It is suspended from a stay by halyards.

Yard A long, nearly cylindrical piece of timber, tapering toward the ends, used for supporting and extending a sail to the wind.

Yard arms See braces.

Reprinted without permission from the Patrick O'Brian Page.

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