Glossary of Nautical Terms

This is a comprehensive glossary of terms relating to shipbuilding and sailing. Citations are as follows:

CD1919: Charles Desmond, 1919, Wooden Ship-Building, New York: Rudder Publishing Company.

FH1991: Frederick Hocker, 1991, The Development of a Bottom-Based Shipbuilding Tradition in Northwestern Europe and the New World, PhD dissertation, Department of Anthropology, College Station: Texas A&M University.

FH2004: Frederick Hocker, 2004, Glossary of Nautical Terms, pp. 377-381, The Philosophy of Shipbuilding: Conceptual Approaches to the Study of Wooden Ships, F. Hocker and C. Ward (ed.), College Station: Texas A&M University Press.

JRS2006: J. Richard Steffy, 2006, Wooden Ship Building and the Interpretation of Shipwrecks, third edition, College Station: Texas A&M University Press.

RJW2008: R. Julian Whitewright, 2008, Maritime Technological Change in the Ancient Mediterranean: The Invention of the Lateen Sail, PhD dissertation, Department of Archaeology, Southampton: University of Southampton.

Glossary of Nautical Terms


abaft (prep.): behind. FH2004

aft (adv.): toward the stern. FH2004 

amidships (adv.): in the middle of the vessel, midway between bow and stern or at the widest part of the vessel. FH2004

aphlaston (n.): curving ornament at the head of the sternpost; such an ornament is typical of Classical warships. FH2004

apical rope groove (n.): groove found at the apex of a stone anchor, used to seat the anchor rope. FH2004

astern (adv. or prep.): behind the vessel. FH2004

athwartships (adv.): lying or running in a direction across the vessel, at a right angle to the centerline. FH2004


backstay (n.): a stay (q.v.) running aft from the head of the mast to provide longitudinal support to the mast. The stay can be belayed on the centerline, often by attachment to the sternpost, or it can lead to one side. If the latter, there are normally pairs of backstays to balance the lateral stress. FH2004

baldachin (n.): a simple canopy, normally consisting of a curved roof supported on four pillars, typically found on Egyptian craft, where they are often used to shelter important persons. The baldachin may be fixed or portable. FH2004

ballast (n.): dense material, typically stone, placed low in the hold of a vessel to lower the center of gravity and increase stability. FH2004

batten (n.): thin strip of wood or fiber placed against the inner surface of planking at a seam, either to cushion seam ligatures or to act as caulking. FH2004

beam (n.): (1) width of a vessel amidships or at the widest point. Extreme beam is the overall width to the outside of planking, wales, rubrails, and so on, while molded beam is the width to the inside surface of the planking. (2) A transverse timber, straight or crowned, fastened at its ends to the sides of the hull: beams can act as thwarts or support decks. FH2004 

beam shelf (n.): a stringer (q.v.) that supports the ends of deck beams. FH2004

belaying pin (n.): wooden pin for the temporary attachment of the free end of an element of the running rigging. FH2004

bireme (n.): a rowed vessel with two banks of oars on each side. In ancient biremes, the two banks were set at different levels. FH2004

boom (n.): spar used to spread the foot of a sail. FH2004

boom-footed rig (n.): type of square rig, common on certain ships of the Bronze Age, in which the foot of the sail is attached to a boom. FH2004

bow (n.): the end of the vessel toward the normal direction of travel; the "front" end. FH2004

bow patch (n.): circular, spoked device seen on the upper hull at the bow of Geometric ship representations. FH2004

brace (n.): element of the running rigging (q.v.) attached to the yardarm (q.v.) to adjust the angle of a square sail to the wind. They are used in pairs, one on each yardarm. FH2004

brail (or brailing line) (n.): line used to gather up a sail. In ancient square rigs, a number of brails were used to control the shape of the sail and trim it to suit the point of sail and existing wind conditions. FH2004

brailing fairlead (n.): ring, grommet, eye, or loop attached to the yard or sail to guide a brailing line. FH2004

bulwarks (n.): the topsides above the deck: may consist of a planked continuation of the side or may be only lightly planked or open. FH2004

butt end (n.): squared, unscarfed end of a timber, such as a plank or beam. FH2004

butt joint (n.): joint between the ends of two members in which neither member is scarfed or notched to receive the other; the timbers meet at butt ends. FH2004 


caprail (n.): a railing atop the sheerstrake or bulwarks, normally defining the upper edge of the side of the vessel. FH2004

carling (n.): a longitudinal timber fixed to the beams but not to the sides of the vessel. It may be continuous or consist of short pieces between adjacent beams. FH2004

ceiling (n.): planking over the inboard surface of the frames. FH2004

chine (n.): angular join of bottom to side instead of a rounded bilge. FH2004

clamp (n.): a heavy stringer (q.v.) normally set opposite a wale. A clamp often supports deck beams, in which case it may be called a deck clamp. See also beam shelf. FH2004 

cleat (n.): (1) small block of wood, nailed to the surface of another timber either as a fastening or a stop. (2) A block of wood with horns or ears, used for the belaying of running rigging. FH2004

clew (n.): either corner at the foot of a square sail (q.v.) or the after corner of a fore-and-aft sail (q.v.). FH2004

coracle (n.): small boat of wicker frame covered with animal hide. FH2004

crow's nest (n.): small platform attached to the mast near its head, used by lookouts, archers, or slingers as a vantage point. FH2004

crutch (n.): stanchion or prop that supports long spars, such as mast and yard, when they are not in use. FH2004

cutwater bow (n.): bow with a projecting forefoot somewhat resembling a waterline ram but not normally used as a weapon. FH2004


deck (n.): approximately horizontal platform across the interior of the hull, normally constructed of a layer of longitudinal planks fastened to or resting on a series of transverse beams. FH2004

deck beam (n.): a beam that supports a deck. FH2004

diem (n., Greek): an oared vessel rowed by two groups of men: normally assumed to be synonymous with bireme (q.v.1). FH2004

dovetail joint (n.): rigid joint, frequently used where two members join at a right angle, in which the end of one member is formed into a flared, shouldered face tenon that fits into a matching face mortise in the longitudinal edge of the second member. FH2004 

dowel (n.): a wooden rod. In structural terms, it is used to align two timbers, normally edge-to-edge. FH2004

dugout (n.): a vessel carved from a solid log, normally in one piece. Extended dugouts have pieces, such as side planks, added to the dugout base; expanded dugouts are broadened by softening and spreading the sides of the hull. FH2004


edge-joined (adj.): joined edge-to-edge. Refers here to several methods of ancient Mediterranean hull construction in which adjacent planks were fastened to each other, either by lashing or wooden tenons, passing through their common edges. FH2004


floor (n.):-the bottom of the vessel amidships. FH2004

floor timber (n., sometimes abbreviated to floor): the central component of a frame that crosses the keel (thus spanning the floor). FH2004

foot (of a sail, n.): the lower edge of a sail. FH2004

fore (adj.): pertaining to the bow or closer to the bow. FH2004

fore-and-aft rig (n.): a sailing rig in which the sail or sails are set with the plane of the sail parallel to the centerline of the ship instead of athwartships. FH2004

forecastle (n.): a raised structure built at the bow of a vessel. FH2004

forestay (n.): stay (q.v.) running forward from the head of the mast to provide longitudinal support to the mast. It is often attached at its lower end to the stem. FH2004

frame (n., also timber): a transverse reinforcing member, made up of one or more components, fastened to the interior surface of the exterior hull planking and sometimes to the keel. FH2004 

furl (v.): to bundle up a sail when it is not is use. Square sails are often folded or rolled up and tied to the yard. FH2004


galley (n.): large seagoing vessel propelled primarily by oars. FH2004

gangway (n.): a narrow deck running either along the side of the vessel or down the centerline to connect small decks at the ends of the ship. It is often used on vessels with open holds or oared ships to allow the sailing crew to move around the ship. FH2004

garboard (n.): the strake nearest the keel, or the lowest side strake in some flat-bottomed vessels, such as the Cheops ship. FH2004

 gripe (n.): a projecting fin, either part of or attached to the forward face of the stem below the waterline. FH2004

 grommet (n.): loop made of rope or leather. It has many uses, such as for oarlocks or brailing rings. FH2004


halyard (n.): line for hoisting and lowering a sail: can be attached either directly to the sail or to a spar, such as a yard. FH2004

hawser (n.): heavy rope, normally used for mooring. FH2004 

head (of a sail, n.): the upper edge of a sail. FH2004

helm (n.): the apparatus for steering the ship, as well as (more abstractly) the steering quality of the ship. FH2004

helmsman (n.): the crew member steering the vessel. This may be an official rank or position, or it may be just one of the many tasks performed by all members of a small crew in rotation. FH2004

hog (n. and v.): vertical distortion of the hull in which the ends droop and the middle rises. FH2004

hogging truss (n.): an arrangement of ropes (and sometimes props) connecting the ends of the ship and pulling them up, to counteract hogging. FH2004

hull (n.): the body of the vessel, consisting of the structural timbers that give the ship its shape and strength but excluding rigging, fittings such as windlasses, and the contents of the hold. FH2004


interscalmiurn (n. Latin, "between tholes"): the distance between thole pins or oarlocks in a rowed vessel. FH2004


joggle (v.): to cut a step, or a series of steps, in a timber to fit another; commonly used in ancient Egyptian ship construction. FH2004


kedge (v.): to pull a vessel through the water by carrying an anchor away from the vessel, dropping it, and hauling the vessel up to the anchor. This is most commonly done when the vessel is becalmed or in an attempt to free a grounded vessel. In later times, some vessels carried a special anchor, called a kedge anchor, designed specifically for this purpose. FH2004

keel (n.): central backbone timber, of sufficient cross-sectional area to offer significant longitudinal strength to the hull. In most cases, a portion of it projects below the bottom planking and offers lateral resistance. FH2004

keel plank (also plank keel, n.): centerline strake, often thicker than the adjoining garboards but not stiff enough to be considered a true keel. FH2004

keelson (n.): an internal centerline timber lying atop the frames, of sufficient length, cross-sectional area, and rigid fastening to add significantly to the longitudinal stiffness of the hull. The maststep may be cut into the keelson, or it may be a separate timber fastened to the upper surface of the timber. FH2004


L-shaped lashing mortise (n.): a lashing mortise (q.v.) in which one end of the mortise exits the interior plank surface and the other exits the plank edge. FH2004

lanyard (n.): (1) a length of light-to-medium line used for tightening stays. (2) A short length of light line attached to a small, portable object to prevent its being lost. FH2004

lashed construction (n.): the joining of structural components by wrapping them with several passes of rope or cord. This is also applied to a style of Egyptian shipbuilding in which planks are fastened to each other by several turns of heavy cord passing through a common mortise or series of common mortises. See sewn construction. FH2004

lashing mortise (n.): a mortise, open at both ends, through which lashing ropes or cords pass. FH2004

lateen rig (n.): a fore-and-aft rig (q.v.) in which a triangular sail is set on a diagonal yard raised on a mast. FH2004 

launch (n.): a small boat, often used as a ship's boat. FH2004

leech (n.): the leeward edge of a sail. On a fore-and-aft sail it is always the after edge, but it may be either edge of a square sail, depending on how the sail is trimmed. FH2004

leeward (adv.): the side of a vessel or object that is away from the wind. FH2004

lift (n.): a line supporting the weight of a yard or a boom, normally running from the masthead to the yardarm, but may run to another part of the yard. See running lift, standing lift. FH2004

line (n.): rope or cord, especially a piece of cordage set up to do a specific job on board ship. FH2004 

loom (n.): the part of an oar, usually square or cylindrical in section, between the blade and the handle. FH2004

luff (n.): the leading or windward edge of a sail. On foreand-aft sails it is always the forward edge, but it may be either edge of a square sail, depending on how the sail is trimmed. (v.): to sail too high into the wind, so that the leading edge (luff) of the sail ceases to work effectively and starts to tremble or flap. FH2004


mast (n.): vertical spar fixed to the hull to carry sails, either directly or attached to other, movable spars. FH2004

mast cap (n.): a fitting attached to the head of the mast and supporting a number of sheaves, slots, or rings for rigging, such as lifts (q.v.). Such fittings were used on some Bronze Age vessels to handle the large number of lifts and other lines associated with certain versions of the square rig. See truck. FH2004

masthead (n.): the uppermost portion of the mast, above the highest position of the uppermost sail or yard. This area is used for the attachment of stays and other rigging. FH2004

mast partner (n.): a structure at deck level (or above the step in undecked vessels) to support the mast. The partner is primarily a transverse support but can also be used as a longitudinal support. The partner, combined with the rigging, transmits most of the driving force of the sail to the hull. FH2004

maststep (n.): a mortise to house the heel of a mast and/or the timber into which it is cut. FH2004

midships (adj): located or pertaining to amidships, as in the midships section. FH2004

monoxylon (n.): a dugout (q.v.) carved from a single tree. FH2004

moor (v.): to secure a vessel, temporarily or semi-permanently, either by anchoring or by tying to other structures, such as a pier or wharf. FH2004

mortise-and-tenon joint (n.): an edge-to-edge planking fastening commonly used in the ancient Mediterranean. Each joint consists of a free tenon housed in mortises in opposing edges of a seam: in its fully developed form, the tenon is locked into each plank by a wooden peg driven through plank and tenon. FH2004


nuggar (n.): a small to medium-sized Nile vessel of the historic period characterized by edge-fastened planking and the absence of internal framing. FH2004


oar (n.): a long, narrow piece of wood having a broad blade at one end and a handle at the other, supported in a fixed mounting, such as a thole (q.v.) or oarlock (q.v.), and used to propel a vessel by pulling or pushing the handle, causing the blade to push against the water. FH2004

oarlock (n.): a mounting for an oar characterized by a vertical member both before and abaft the oar. In modern vessels, the oarlock is a U-shaped casting that pivots with the oar, but in older watercraft an oarlock can be as simple as a pair of thole pins. FH2004

oculus (n.): device in the form of an eye, often used as a decorative or apotropaic element on watercraft. FH2004

outrigger (n.): any structure that extends off one or both sides of a vessel. Such structures may support pontoons for added stability, as on Polynesian canoes, or tholes, as on modern rowing shells. FH2004


papyriform (adj.): having the shape of a bundle of papyrus reeds: normally used to describe Egyptian wooden vessels built in the same general shape as Nilotic reed rafts. FH2004

penteconter (n.): an ancient Greek warship rowed by fifty men, arranged in twenty-five pairs on a single level. port (adj. or adv.): left side when facing forward. FH2004

protokeel (n.): a longitudinal centerline timber having some of the characteristics of a true keel (such as substantially greater scantlings than the adjoining planking) but lacking others (such as firm attachment to the rest of the hull structure). FH2004


quarter (n.): the side of the vessel at the stern. FH2004

quarter rudder (n.): a rudder (q.v.) instead of a steering oar (q.v.) fixed to the side of the hull at the stern; i.e., on the quarter (q.v.). FH2004


refit (v.): to repair or overhaul a vessel in a thorough, systematic way, often incorporating modifications and improvements. FH2004

rigging (n.): the system of cordage fitted to spars and sails to support and control them. FH2004

rowlock (n.): see oarlock. FH2004

running lift (n.): a lift (q.v.) that can be adjusted to support the weight of a yard or boom at any position. FH2004

running rigging (n.): lines attached to spars and sails that can be easily hauled or slacked to adjust the height and attitude of sails and spars. FH2004


scarf (n.): a joint in which timbers with parallel axes overlap longitudinally. FH2004

sewn construction (n.): any of a number of construction methods in which adjacent planks are fastened together by fiber stitching. The stitching may be continuous along the seam (in the manner of garment sewing), or it may consist of individual ligatures (in the manner of medical sutures). FH2004

sheave (n.): a pulley, set either in a separate housing (a block) or in a slot in a spar or hull component. FH2004

sheer (n.): the upper edge of the uppermost continuous strake of exterior planking. In many smaller vessels, this is the upper edge of the side. In larger vessels, the sheer, sometimes called the planksheer, may be below the bulwarks and other upper works. See sheerstrake. FH2004

sheerstrake (n.): the uppermost continuous strake of structurally significant planking; on vessels with light bulwarks, the sheerstrake may actually be at deck level. FH2004 

sheet (n.): line attached to the clew (q.v.) of a sail and used for trimming the sail. FH2004

shell-based construction (n.): hull construction methods in which the shell of planking plays the primary role in determining the shape of the hull and provides the greater share of structural strength. Most ancient methods of construction were shell-based. FH2004

shell-first construction (n.): hull construction methods in which the shell of planking is the first major component erected, generally after the keel. The finished hull may be shell- or skeleton-based. FH2004

shroud (n.): a stay (q.v.) that provides transverse support to a mast; it runs from the masthead to the vessel's side. FH2004 

sidereal compass (n.): a method of determining direction from the positions of rising and setting stars. FH2004

skeleton-based construction (n.): hull construction methods in which an internal framework, usually consisting of frames and stringers (q.v.), plays the primary role in determining the shape of the hull and provides the greater share of structural strength. Most ancient methods of construction evolved toward skeleton-based methods. FH2004

skeleton-first construction (n.): hull construction methods in which an internal framework is the first major component erected, generally after the keel. Such hulls are usually, but not always, skeleton-based. FH2004

Spanish windlass (n.): a device for exerting tension by twisting ropes strung between two fixed points. FH2004

spinnaker (n.): a large, baggy, triangular sail on modern yachts, set forward when sailing before the wind. FH2004

square sail (n.): a sail, normally set on a yard (q.v.) at right angles to the centerline of the vessel. FH2004

stanchion (n.): a vertical post supporting a load above. FH2004 

standing lift (n.): a lift (q.v.) of fixed length that supports the weight of a yard or boom in only one position, generally when the yard is lowered. FH2004

standing rigging (n.): rigging of more or less fixed length, used to support a spar in a certain position. Although it may be adjusted slightly in use, it is not commonly hauled, slacked, or belayed with every change of sail. FH2004

starboard (adj. or adv): right side when facing forward. FH2004

stave (n.): one of the long, narrow pieces of wood used to build a cask or barrel. The term also applies to wooden members used in other forms of similar construction. FH2004

stay (n.): an element of the standing rigging (q.v.) that supports a mast. See forestay, backstay, shroud. FH2004 

steering oar (n.): an oar used for steering. It pivots on a thole or oarlock and is used by sweeping it through the water to push one end of the vessel across the line of travel. It is less efficient than a rudder. FH2004

stem (n.): the upright backbone timber rising from the forward end of the keel or keel plank. It may denote either the specific timber into which the plank hooding ends are rabbeted in a complex assembly or the entire assembly. FH2004

stern (n.): the end of the vessel away from the normal direction of travel; the "back end. FH2004

sternpost (n.): the upright backbone timber rising from the after end of the keel (keel plank). It may denote either the specific timber into which the plank hooding ends are rabbeted in a complex assembly or the entire assembly. FH2004

strake (n.): a continuous run of planking, made up of one or more planks joined or butted end-to-end. FH2004

stringer (n.): a heavy longitudinal timber, such as a clamp, on the interior of the vessel. FH2004

sweep (n.): a long, heavy oar, typically operated by two or more men. FH2004


tabernacle (n.): a mast partner (q.v.) designed to allow the mast to be stepped and struck by leaning it forward and backward, respectively. FH2004

tenon (n.): a tongue on the end of a member, or a separate element, designed to be housed in a mortise and used to join components. FH2004

thole (n.): a fixed pivot point for an oar, generally consisting of a pin or hook fixed to the side of the vessel. The oar may rest either before or abaft the thole. FH2004

thole bight (n.): a grommet of rope or leather to attach an oar to a thole. It can serve either to transmit the force of the oar to the hull (if the oar lies before the thole) or simply as a keeper, to prevent the oar from being lost if it is let go. FH2004

thole-board (n.): a strake or other longitudinal timber into which the tholes or oarlocks are fitted. FH2004

through-beam (n.): a beam (q.v.) that passes completely through the sides of the vessel so that the ends are visible from outboard. This is often done in an attempt to fasten the beam securely to the side by notching it over a wale. FH2004 

thwart (n.): a simple seat, consisting of a board set athwartships. In some vessels, the thwart may also act as a beam (q.v.) if properly fastened to the sides. FH2004

tiller (n.): a straight or curved piece fixed at an angle to the head of the rudder to give the helmsman leverage or to allow him to steer when the rudder head is out of normal reach. FH2004

toggle (n.): a short wooden bar, often with swelled ends, seized or spliced into the end of a rope to allow another rope, with a loop in its end, to be rapidly attached. FH2004

transom (n.): (1) a transverse timber in the stern, crossing the inner face of the sternpost assembly and holding the sides together. Sometimes called a transom timber to distinguish it from the flat, transverse plane forming the stems of some vessels. (2) A flat, transverse plane forming the stern of the vessel. FH2004 

treenail (n.): a wooden peg of substantial size used to fasten together two members, such as a plank and a frame. FH2004

trieres (n.): Greek oared warship rowed by three groups of oarsmen, probably set at three levels. FH2004

truck (n.): a sheave (q.v.), slot, or ring in the head of the mast to take a line for raising and lowering something. See mast cap. FH2004

truss (n.): an element designed to exert tension in a structure and provide it with rigidity. In ancient ships, rope trusses were sometimes run between the ends of the hull, either to compress the entire hull and thus increase its strength and rigidity through preloading or to pull the ends up and reduce hogging. See hogging truss. FH2004

truss girdle (n.): a girdle of ropes around a hull to hold the hull together or to provide a point of attachment for a truss. FH2004

tumble-home (n.): hull shape in which the upper parts of the hull lean inward, toward the centerline. FH2004


V-shaped lashing mortise (n.): a lashing mortise (q.v.) in which both ends of the mortise exit the same surface of the plank. FH2004


wale (n.): an exceptionally heavy strake. FH2004

waterline (n.): the imaginary line on the hull that marks the level of the water surface when the vessel is afloat. Some vessels have a waterline painted on or inscribed in the hull. FH2004 

webbing (n.): a woven or plaited strap used in place of several turns of lashing in some ancient Egyptian hulls, such as the one at Lisht. FH2004

wind rose (n.): a diagram of geographic directions in which a series of points corresponds to the origins of known, prevailing winds. Common wind roses in the West are derived from ancient wind systems that divided the compass into eight or twelve points. FH2004

windlass (n.): a mechanical device for multiplying human force in hauling in ropes. It consists of a horizontal barrel of circular or polygonal section set in a fixed mounting, which is turned by bars set in holes in the barrel. FH2004

woolding (n.): a binding used to hold together a mast of composite construction. FH2004


yard (n.): a spar set athwartships on a mast to support a square sail. FH2004

yardarm (n.): the end of the yard, outboard of the sail, where controlling lines such as braces (q.v.) are attached. FH2004

Diagrams of Ship Construction Terms


Shipbuilding Terms Hull Parts

Shipbuilding Terms, Hull Parts Labeled on the Flower of Ugie by Julian Whitewright.

Shipbuilding Terms, Cross Section

Shipbuilding Terms, Cross Section- CD1919

Shipbuilding Terms, Bow Structure

Shipbuilding Terms, Bow Structure-CD1919

Shipbuilding Terms, Stern Structure

Shipbuilding Terms, Stern Structure- CD1919

Shipbuilding Terms, Deck Structure

Shipbuilding Terms, Deck Structure- CD1919

Shipbuilding Terms, Sided and Moulded

Shipbuilding Terms, Sided and Moulded, Timber and Space (also known as Room and Space)- CD1919

Shipbuilding Terms, Sectional

Shipbuilding Terms, Sectional- CD1919

Shipbuilding Terms, Plan

Shipbuilding Terms, Plan- CD1919

Glossary of Rig Types, Sails, and Rigging

Tall Ship Rig Types by Julian Whitewright

Diagram of ships' rigs by RJW2008. 

Sails Names on a Square Rigger

Diagram of ship's sails by RJW2008. 

Parts of a Sail


Diagram of the parts of a sail by RJW2008.

Rigging and Sail Terms on a Mediterranean Vessel


 Diagram of the parts of a Mediterranean sailing rig by RJW2008.

Glossary of Navigation Terms

Tacking and Wearing

Diagram of Tacking and Wearing from RJW2008.


Sailing Points

Diagram of Sailing Points from RJW2008.

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