| Term | Definition |
|---|---|
| aft | (Or after.) Near, toward or at the stern of a ship. |
| after cabin | In a ship with multiple cabins, the cabin closest to the stern. |
| aftermast | In a sailing ship carrying multiple masts, the mast set closest to the stern. Also called the mizzenmast in a three-masted sailing vessel. |
| aftermost | The farthest aft. |
| amidships | In or toward the part of a ship midway between bow and stern. |
| arch | A curved architectural structure used to support suspended weight. In Great Lakes wooden shipbuilding, a wide iron- or steel-fastened strap down each side of a ship, usually fastened low in the bow and stern and rising to the level of the upper deck amidships; provides longitudinal support to the hull. |
| arch board | An arch-shaped nameboard fastened to the stern of a ship, displaying the vessel's name and home port. |
| athwartships | Perpendicular to the fore-and-aft centerline of a ship; sideways. |
| backstay | Mast support running from the top of the mast to the aft deck or another mast. |
| ballast | Material used to improve the stability and control of a ship. In wooden ships usually stone, lead or iron; in metal ships, often water. |
| barge | A large cargo-carrying craft that is towed or pushed by a tug on both seagoing and inland waters. |
| barque | (Also bark.) A sailing ship with three to five masts, all of them square-rigged except the after mast, which is fore-and-aft rigged. |
| basket truss | Iron lattice work of bracing that prevents a hull from hogging and sagging. |
| beam | The width of a ship at its widest point. |
| bilge | 1. Part of the underwater body of a ship between the flat of the bottom and the straight vertical sides. 2. Internally, the lowest part of the hull, next to the keelson. |
| black gang | Nautical slang for the engineroom crew. Included the chief engineer, who ran the engine and supervised; oilers and wipers, who lubricated and maintained the engine; and firemen and coal-passers, who fed the steam boilers. |
| block | A metal or wood case enclosing one or more pulleys; has a hook with which it can be attached to an object. |
| board foot | A unit of quantity for lumber equal to the volume of a board that is 12 by 12 by 1 inches. |
| boatswain | The officer in charge of sails, rigging, anchors, cables, etc. Pronounced "bosun." |
| bobstay | A chain or heavy wire rigging running from the end of the bowsprit to the ship's stem or cutwater. |
| boom | A spar extending from a mast to hold the outstretched bottom of a sail. |
| bosun | Short for boatswain. |
| bow | The forward part of a ship. |
| bowsprit | A large spar that projects forward from the forward end of a sailing ship; used to carry sails and support the masts. |
| break-bulk trade | Loose cargo, such as cartons, stowed directly in a ship’s hold, as opposed to bulk cargo. |
| breeches buoy | A device used by lifesaving crews to extract persons from wrecked vessels, usually fired from a cannon onto the deck of the wrecked vessel. |
| bridge | An elevated structure extending across or over the weather deck of a vessel, containing stations for control and visual communications. |
| bulkhead | An upright partition separating compartments in a ship. |
| bulwark | The part of a ship's side that extends above the main deck to protect it against heavy weather. |
| bulwarks | The part of a ship’s side that are above the upper deck. |
| bunker | A storage compartment aboard a ship for coal or other fuel. |
| bushel | A unit of volume (dry measure) used in the United States, equal to 32 quarts or approximately 35.2 liters. |
| bustle | Framework and hull plating added on a vessel’s centerline to widen a ship. |
| cabin | An enclosed compartment in a ship; used as shelter or living quarters. |
| camber | The arch or slope from side to side of a vessel's weather deck for water drainage. Also known as round of beam. |
| cant frames | Angled frames in the extreme forward or aft ends of a ship which form the sharp ends of the vessel's hull. |
| capstan | A vertical, spool-shaped rotating drum around which cable, hawser or chain is wound for hoisting anchors, sails and other heavy weights. |
| cathead | A heavy piece of timber projecting from the bow of a ship for holding anchors. |
| ceiling | The inside planking or plating in the hold of a merchant vessel, laid across the floors and carried up the sides of the holds to the level of the beams. |
| centerboard | A metal or wooden slab housed in a casing or trunk along the centerline of a sailboat; may be lowered to increase the boat's resistance to sideways motion and raised when the boat is in shallow water or beached. |
| centrifugal | A pump that uses centrifugal force for pumping liquids. (Also, moving or tending to move away from a center.) |
| chain locker | A compartment in the lower part of a ship for stowing an anchor chain. |
| chain plate | A steel plate or bar by which standing rigging is attached to the hull. |
| chandler | A retail dealer in supplies and equipment. |
| chord | The principal horizontal member in a rigid framework. In Great Lakes shipbuilding, a heavy horizontal metal strap fastened around a hull at the level of the upper deck , supporting a framework of arches and cross bracing. |
| clinch ring | A metal washer peened onto an iron bolt to help secure timbers. |
| clipper | A sharp-bowed sailing vessel of the mid-19th century, having tall masts and sharp lines; built for great speed. |
| coaming | A rim placed on a roof or around a hatch, deck or bulkhead opening to stop water from entering. |
| coasting trade | Water-borne trade conducted among ports of a single country. |
| combination pump | A dual-purpose steam engine that conducted multiple tasks such as pumping water and hoisting. |
| consort | An unpowered Great Lakes cargo vessel, usually a schooner-barge, towed by a steam barge or a steamer. A large steamer could tow several consorts, each fully loaded with bulk cargo. The consort system began in the 1860s on the Great Lakes and persisted to around 1920. "Consort" can refer to a pair of such vessels or just the towed vessel. |
| covering board | The outermost plank of the upper deck, running beneath the base of the bulwark and covering the frametops and the ends of the deck beams. |
| cross bracing | Iron or steel straps fastened diagonally across a ship's frames to make a rigid framework. |
| cross trees | Two horizontal pieces of timber or metal on each side of a mast that spread the upper shrouds, helping to support the mast. |
| cutwater | The forward curve of the stem of a ship. |
| deadeye | A circular block of wood with three holes used to receive a shroud or stay and to adjust tension in the standing rigging. |
| deadwood | Heavy longitudinal timbers fastened over the keelson. The timbers of the bow and stern are fastened to the deadwood. |
| deck | Horizontal or cambered and sloping surfaces on a ship, like floors in a building. |
| deckhouse | A low building or superstructure, such as a cabin, constructed on the top deck of a ship. |
| depth of hold | The measurement from beneath the deck to the bottom of the hold; the vertical space in the cargo hold. |
| derrick | A hoisting machine consisting usually of a vertical mast, a slanted boom and associated tackle; may be operated mechanically or by hand. |
| dolphin striker | A short spar perpendicular the bowsprit, used with martingales for holding down the jib-boom. The position is such that a dolphin leaping at the bow of a vessel could possibly be struck by this spar. |
| donkey boiler | A steam boiler on a ship deck used to supply steam to deck machinery when the main boilers are shut down. |
| donkey engine | A small auxiliary steam engine with its own small boiler, used for furnishing power for a variety of smaller mechanical duties |
| drift bolt | An long iron rod used to tie together timbers, often driven into a hole slightly smaller than its own diameter. |
| engine bed | A structure of wooden or metal supports that make up the mounting for a ship's engine. |
| fall | A hoisting rope or chain, especially the part of rope or chain to which power is applied. |
| fantail | The area of the upper deck of a ship that is nearest the stern. More specifically, a rounded afterdeck that overhangs the propeller and rudder. |
| fastening | A spike, bolt or other device used to connect one piece of wood to another. |
| fetch | To reach or arrive at some place or point, particularly in conditions of an adverse wind or tide. |
| figurehead | A carved and painted ornamental figure on the stern of the vessel. |
| fittings | Equipment and consumable goods placed on a ship in preparation for its active service and required by its allowance list or for operation. |
| floor keelson | Timbers bolted to the floors and running parallel to the main keelson. |
| fluke | The broad end of each arm of an anchor. |
| following sea | A sea in which the waves are moving in the same direction as the vessel. |
| fore | 1. The front part of a ship. 2. In the direction of or toward the bow. |
| forecastle | The section of the upper deck of a ship located at the bow forward of the foremast. |
| forefoot | The bottom of the bow, where the stem curves into the keel. |
| foremast | The forward-most mast on a sailing vessel with two or more masts. |
| forestay | A line supporting a mast, running from the bowsprit or foredeck of a boat to the upper part of the mast. |
| forward | Toward the front of a vessel. |
| frame sets | Groups of frames. |
| frames | The transverse strengthening members in a ship's hull that extend from the keel to the deck or gunwale. |
| frametops | The tops of a ship's frames; the transverse strengthening members in a ship's hull that extend from the keel to the deck or gunwale. |
| futtock | A curved or vertical timber that when paired with a floor or additional futtocks makes the frame of a wooden ship. |
| gaff | A spar used to extend the top edge of a fore-and-aft sail. |
| gaff-topsail | A light triangular or quadrilateral sail set over a gaff. |
| gale | 1. An unusually strong wind. 2. In storm-warning terminology, a wind of 28-47 knots (52-87 kilometers or 32-63 miles per hour). |
| galley | The kitchen of a ship or airplane. |
| gangway | An opening in the ship’s side through which cargo is loaded and unloaded, or a ramp by which passengers enter or leave a ship. |
| GPS | (Global Positioning System) A navigation system that uses satellites to provide a receiver anywhere on Earth with extremely accurate measurements of its three-dimensional position, velocity and time. |
| gross tonnage | The overall volume of a ship's hull, including crew cabins, storerooms and machinery spaces. A ton equals 100 cubic feet. The calculation of tonnage is complex, and a major revision in tonnage calculation laws occurred in 1864. The term "old measurement" reflects measurements before this change. See also net tonnage. |
| ground swell | A broad, deep undulation of water caused by an often distant gale. |
| gunwale | The upper edge of the side of a boat. Also spelled gunnel. |
| gusset | A brace, usually triangular, for reinforcing a corner or angle in the framework of a structure. |
| hanging knees | Vertical wooden brackets shaped somewhat like human knees; used to support deck beams. |
| hank | An iron ring for hooking a staysail to a stay. |
| hatch | A door or opening, especially on an airplane, spacecraft or ship. |
| hawse hole | An opening in the hull, through which anchor chains (sometimes called hawsers) are run. Usually fitted with a hawsepipe. |
| hawsepipes | Pipes made of heavy cast iron or steel through which the anchor chain runs; placed in the ship's bow on each side of the stern, or in some cases also at the stern when a stern anchor is used. |
| hawser | A large rope or cable -- usually more than 5 inches (13 centimeters) in diameter -- used to tow or moor a ship or secure it at a dock. |
| head gear | The bowsprit and associated rigging of a sailing vessel. |
| heel | For a ship to incline or be inclined to one side. |
| helm | The tiller or wheel controlling a ship's rudder. |
| hog | To bend downward at the bow and stern for lack of longitudinal strength or rigidity. See also sag. |
| hoist | A power unit for lifting, usually designed to lift from a position directly above the load. |
| hold | The interior of a ship or plane, usually referring to the cargo compartment. |
| horn timber | A heavy longitudinal timber that angles upward from the stern to support the underside of the fantail. |
| horsepower | A unit of power equal in the United States to 746 watts; nearly equivalent to the English gravitational unit of the same name that equals 550 foot-pounds of work per second. |
| hull | The body or shell of a ship. |
| inboard | Inside the hull or bulwarks of, or toward the center of, a ship or boat. |
| jaws | A semi-circular fitting at the end of a gaff or boom that holds the gaff or boom on a mast. |
| jib | A triangular sail bent to a foremast stay. |
| jib boom | A smaller spar mounted atop the bowsprit to extend its length. |
| keel | A steel beam or timber, or a series of steel beams and plates or timbers joined together, extending along the center of the bottom of a ship from stem to stern and often projecting below the bottom, to which the frames and hull plating are attached. |
| keelson | A structure of timbers or steel beams that are bolted to the top of a keel to increase its strength. Also spelled kelson. |
| king post | A strong vertical post used to support a ship's windlass and the heel of a ship's bowsprit. Also called a sampson post. |
| knee | A timber or metal bar fashioned into a right angle to provide strengthening and support at the intersection of timbers in wooden ships. |
| knot | A speed unit of 1 nautical mile (6,076 feet or 1.852 kilometers) per hour. |
| latitudinal | Running or oriented side-to-side (or athwartships) on a ship. Frames, for example, are latitudinal timbers. See also longitudinal. |
| launch | A small propeller-driven boat. |
| lighter | A barge used to load and unload ships not lying at piers, or to move cargo around a harbor; to unload. |
| limberboard | A ceiling plank next to the keelson that could be removed to access the bilge and limberways. |
| limberways | Notches cut fore-and-aft through the bottom of the floors, allowing water to run through the bilge to the pumps. |
| longitudinal | Running or oriented fore-and-aft (along the long axis) of a ship. Keelsons, for example, are longitudinal timbers. See also latitudinal. |
| LORAN | Long-range navigation system that uses radio signals transmitted at specific times. An onboard receiver computes position by measuring the difference in time of signal reception. |
| main deck | The principal deck of a ship. In ships with multiple decks, the deck beneath the spar deck. |
| mainchains | Heavy steel plates fastened to a ship's sides that anchor the rigging for the mainmast. |
| mainmast | The principal mast of a sailing ship. |
| mast | A long wooden or metal pole or spar, usually vertical, on the deck or keel of a ship, that supports spars and sails. On a sailing ship, supported on the keelson. |
| master | The captain of a merchant ship. |
| mate | A deck officer ranking below the master on a merchant ship. |
| midships | Roughly halfway between a ship's stem and stern. |
| mizzen | A fore-and-aft sail set on the mizzenmast. |
| mizzenmast | The third mast from the bow or the mast aft of the mainmast in a sailing ship. |
| monkey rails | Small rails mounted atop the main rail, increasing the height of the bulwarks. |
| moor | To secure a ship by attaching it to a fixed object or mooring buoy. |
| mooring bitt | A strong pair of iron, steel or wooden posts on a ship's deck, around which ropes or cables are wound and held fast. |
| naphtha | A petroleum distillate that was used in early internal combustion engines. |
| net tonnage | The volume of cargo a ship could carry, equal to gross tonnage minus the crew cabins, storerooms and machinery spaces. One ton equals 100 cubic feet. |
| northeaster | A stormy wind with waves from the northeast. Also spelled nor'easter. |
| oakum | Old hemp or jute fiber, loosely twisted and impregnated with tar or a tar derivative, used to caulk sides and decks of ships and to pack joints of pipes and caissons. |
| oiler | A member of a ship's engineering crew who assisted the chief engineer with lubricating and maintaining the engine. |
| outboard | Outside a ship's bulwarks; in a lateral direction away from the hull . |
| pilothouse | A compartment on or near the bridge of a ship that contains the steering wheel and other controls, compass, charts, navigating equipment and means of communicating with the engine room and other parts of the ship. Also known as wheelhouse. |
| pinion gear | A drive gear on a steam-powered winch. |
| plate | A smooth, flat, relatively thin piece of metal formed in sheets by beating, rolling or casting; used in the construction of ship's hulls. |
| pony boiler | Variation of donkey boiler. |
| port | The side of a ship that is on the left of a person facing forward. |
| purchase rim | The teeth of a ratchet mechanism used to rotate a windlass when raising the anchors. |
| put about | To change the course of a sailing vessel. |
| rabbet | A joint formed by fitting one member into a groove in the face or edge of a second member. |
| rail | The railing around the deck. |
| refasten | The periodic replacement and repair of bolts, spikes and other fastenings that hold together the hull of a wooden vessel. |
| rig | The method by which spars and sails are designed and fitted. |
| rigging | Collectively, all the ropes and chains used to support and work the masts, yards, booms and sails of a vessel. |
| room and space | "Room" refers to the width of a ship's frames, and "space" refers to the distance between frames. Often used by archaeologists to describe and identify wrecks. |
| rudder | A device attached upright to the stern of a ship and used to steer it. |
| running lights | Lights on a ship, displayed when under way to make the vessel more visible to other vessels. Specific requirements depend on the size of the vessel, but the most basic arrangement is a red light on the port side, a green light to starboard, and a white light at the masthead. |
| sag | A vessel is said to sag when its center hangs lower than the ends, due to lack of strength or rigidity. See also hog. |
| salvage | Recovery and reclamation of damaged, discarded or abandoned material, ships, craft and floating equipment for reuse, repair, refabrication or scrapping. |
| scantlings | The dimensions of a ship's principle timbers, or the timbers themselves. |
| scarph | An overlapping joint used to couple two timbers end-to-end without increasing their dimensions. Types include simple butt (flat) scarphs and more complicated hooked and keyed scarphs. |
| schooner | A sailing vessel with two or more masts rigged fore and aft. The foremast is shorter than the other mast(s). |
| schooner-barge | A cargo vessel with a reduced schooner-rig, intended to be towed as a barge by a powered vessel but capable of sailing during emergencies. |
| scow | A large flat-bottomed boat with broad, square ends used along coastal trade routes for transporting bulk material such as ore, sand, or refuse . These shallow draft vessels were often lightly constructed and could be built quickly by small groups of coastal residents using simple materials and tools. |
| scroll head | A scroll-shaped figurehead attached to the bow of a sailing vessel. |
| scuppers | Openings in a ship's hull above the water line that allows water to drain off the deck. |
| shaft | A cylinder used to carry rotating machine parts, such as pulleys and gears, to transmit power or motion. |
| shaft log | A heavy longitudinal timber placed over the keel in a ship's stern through which the propeller shaft passes. |
| shoal | A sandbar or rising bottom that forms a shallow place, which is a danger to navigation. |
| shroud | A line or wire supporting a mast and running from its top to the spreaders, then down to the sides of the vessel. |
| spar | A long, round stick of steel or wood, often tapered at one or both ends, and usually a part of a ship's masts or rigging. |
| spar deck | The upper deck running a ship's full length. In a sailing vessel, the upper deck from which sails, rigging and spars are controlled. |
| spiral wood auger | A hand drill, similar in appearance to a corkscrew, for boring holes in wood. |
| squall | A strong wind with sudden onset and more gradual decline, lasting for several minutes. In U.S. observational practice, a squall is reported only if a wind speed of 16 knots (8.23 meters per second) or higher is sustained for at least 2 minutes. |
| square rig | A sailing-ship rig with rectangular sails set approximately at right angles to the keel line from horizontal yards. |
| stanchion | An upright wooden or metal post on a ship; supports the ship's bulwarks, railing or deck. |
| starboard | The side of a ship that is on the right when a person faces forward. |
| stay | A large strong rope used to support a mast. |
| steam barge | A single-decked steam-propelled bulk cargo carrier ranging from 65 to 200 feet in length, used on the Great Lakes from the 1860s to the 1930s for hauling lumber, stone, coal and other bulk cargoes. |
| steamer | (A steamship.) A ship propelled by a steam engine. |
| stem | The foremost part of a ship's hull . |
| stempost | The principal vertical timber in a ship's bow. |
| stern | The aftermost part of a ship. |
| sternpost | The principal vertical timber in a ship's stern, upon which the rudder is fastened. |
| stockless anchor | An anchor that is not secured to the rail at the bow of a ship, as stock anchors are, but is pulled up into the hawsepipes until the flukes meet the hull. |
| stringer | A long horizontal member used to support a ship's bottom, a building floor or an airplane fuselage. |
| surfman | A member of the U.S. Life Saving Service who rescued stranded crews from shipwrecks. |
| syphon | Variation of siphon. A tube, pipe or hose through which a liquid can be moved from a higher to a lower level by atmospheric pressure forcing it up the shorter leg while the weight of the liquid in the longer leg causes continuous downward flow. |
| tackle | An assembly of lines and blocks in which the line passes through more than one block. |
| tank top | The top of a Great Lakes bulk carrier's bilge tank; a water balast tank forming the bottom of a freighter's hull. |
| taps and dies | Tools for cutting metal threads into parts. |
| topmast | An upper, secondary mast on a sailing vessel, supported by a heavier, lower mast. |
| transom | The flat, vertical aft end of a ship. |
| triple-expansion steam engine | An engine with three steam cylinders of different diameters. Steam passes from a small-diameter high-pressure cylinder to an intermediate cylinder to a large-diameter low-pressure cylinder. These cylinders power the pistons that drive the engine. |
| trunk | The tall, narrow, waterproof box that houses a vessel's centerboard and allows it to be retracted into the ship's hull. |
| tug | (Or tugboat.) A powerful, strongly built boat designed to tow or push other vessels. |
| turn of the bilge | The point where the bottom and the sides of a ship join. |
| weather deck | The uppermost deck of a ship; any deck that does not have overhead protection from the weather. |
| wheel | Slang for a ship's propeller. |
| wheelsman | Another name for the helmsman; one who steers a ship via a wheel. |
| winch | A machine that has a drum on which to coil a rope, cable or chain for hauling, pulling or hoisting. |
| windlass | A machine designed to raise or lower an anchor. |
| worm gear | A long, rotating gear in the form of a screw, which meshes with the teeth of another gear. |
| yard | A long spar, tapered at the ends, attached at its middle to a mast and running athwartships; used to support the top of a square sail. |
| yawl | A two-masted vessel, sloop or cutter rigged on the foremast, with the mizzen mast aft of the rudder-head. |
| yawl boat | A small life-saving boat carried on large vessel. |
| zebra mussel | A small freshwater mollusk that was accidentally introduced to North American waters via ballast water from a transoceanic vessel. The zebra mussel has had significant negative economic and ecological effects: It clogs water intake pipes and attaches to and fouls boat hulls, dock pilings and other objects. |