Back to the main glossary page


Gadget. A slang term applied to various fittings. It is generally used where a proper name for the fitting is hard to decide upon or not remembered.

Gaff. A spar to which the top of a main, mizzen or similar sail is attached. It usually has a jaw fitted at one end to clasp the mast.

Gage. An instrument used in determining the pressure in a boiler, that is, the pressure above the atmosphere. A glass or pipe column, the latter fitted with gage cocks, used to determine the amount of liquid in a boiler or tank. An instrument for measuring dimensions, number of threads, etc. A standard length, thickness or number of threads.

Gage. An instrument or standard of measure used on fine machine work, etc. Some of the most common gages are the micrometer, plug and ring gage, snap gage, thickness gage, limit gage, drill gage, thread gage, wire gage, etc.

Gage Cock. A small cock fitted to a boiler or tank for the purpose of determining whether the liquid within is up to the level that it is fitted at.

Gage, Draft. An installation comprising a glass tube, graduated to scale and a small pipe, in communication with the sea. It indicates, in approximate units, the draft of the vessel.

Gage Glass. A glass tube forming a part of a gage used to determine the amount of liquid in a boiler or tank.

Gage, Jacket. A gage mounted on the steam jacket of a cylinder for the purpose of determining the pressure therein.

Gage Pipe. A small pipe connecting the steam or water gage to a boiler.

Galley. The space on shipboard where the food is prepared; a ship’s kitchen.

Galley Dresser. A cook’s work table located in the galley. It is usually a built-in structure of metal or wood on which the cook prepares the food, having shelves and lockers fitted underneath for stowing miscellaneous cooking utensils.

Galley Equipment. Equipment necessary to a ship galley for cooking, baking, warming, etc. Included in this equipment are ranges, steam tables, cold and hot water urns, vegetable cookers, kettles, etc.

Galley Force Pump. A hand pump used in the galley for drawing fresh water from the tanks below.

Galley Smoke Pipe or Funnel. A smoke pipe fitted to the galley range. It is constructed of sheet iron and led up through the deck above or through the galley skylight to the open air.

Galvanizing. The process of coating one metal with another, ordinarily applied to the coating of a metal (usually iron urn steel) with zinc. The chief purpose of galvanizing is to prevent corrosion.

Gammoning Piece. A timber on top of the filling chocks between the bobstay-piece and stem. An iron band, lashing used to assist in securing the bowsprit to the stem.

Gang board, Gangplank. A term applied to boards or a movable platform used in transferring passengers or cargo from vessel to wharf or dock or vice-versa.

Gangway. A term applied to a place of exit from a vessel. Gangways are fitted in the shape of ports, which may be closed, in the sides of a vessel and in the shape of movable portions of bulwarks or railings on the weather decks.

Gangway Port. See Port, Gangway.

Gantline, Girtline. A rope reeving through a single block aloft and used for hoisting or lowering rigging, etc.

Gantry Crane. See Crane, Gantry.

Garboard Plate. See Plate, Garboard.

Garboard Strake. See Strake, Garboard.

Garland. A strap lashed to a mast by which it is hoisted on board and placed in position.

Gaskets. Packing materials, by which air, water, oil or steam tightness is secured in such places as on doors, hatches, steam cylinders, manhole covers, or in valves, between the flanges of pipes, etc. Such materials as rubber, canvas, asbestos, paper, sheet lead and copper, etc., are extensively used. Ropes or plaited stuff used to confine furled sails to their yards or booms. Harbor Gaskets are usually of plaited stuff named according to their position as yard-arm, quarter and bunt gaskets. A Sea Gasket, also termed a Furling Line, is a long rope passed around both the yard and sail when a neat appearance is not so much desired as security.

Gate Shear. See Shear, Gate.

Gate Valve. See Valve, Gate.

Gear. A comprehensive term in general use on shipboard signifying the total of all implements, apparatus, mechanism, machinery, etc., appertaining to and employed in the performance of any given operation. For instance the brooms, brushes, buckets, dust pans, mops, etc., constitute the "cleaning gear"; the rudder, steering engine or motors, shafting, gears, drums, etc., the "steering gear"; etc.

Gear Cutter, Automatic. A machine designed to cut spur and bevel gears and worm-wheels. These machines are generally automatic, all the operations required in gear cutting being performed by the machine itself except the lacing of the wheels in position and setting the machine for the proper depth and length of cut.

Geared Door. See Door, Horizontal or Vertical, Sliding.

Gearing. A term applied to wheels provided with teeth that mesh, engage, or gear with similar teeth on other wheels in such a manner that motion given one wheel will be impaired to the other

Gemma’s Ring. Also known as the ring dial, this was a development of the Augsburg Dial, a reasonably accurate sun clock.

General Arrangement Plans. The plans showing the various quarters, spaces and compartments into which a ship is usually divided.

General Service, Pump. See Pump, General Service.

Generator, Asynchronous. A commutator type of alternating current generator which does not operate asynchronous speed.

Generator, Compound. A direct current generator in which the field consists of both series and shunt field coils.

Generator, Electric. A machine which transforms mechanical energy into electrical energy.

Generator, Engine Driven. An electric generator driven by gas or steam engine of the reciprocating type.

Generator, Series. A direct current generator in which the field winding is connected in series with the armature winding thus allowing the full armature current to go through the field coil.

Generator, Shunt. A direct current generator in which the field coil is shunted across the armature, thus allowing only a small portion of the armature current to pass through the field coil. The voltage of a shunt generator is very nearly constant, with a slight decrease in voltage as the load increases.

Generator, Synchronous. An alternating current generator the speed of which bears a certain fixed relation to the frequency of the circuit.

Generator, Turbine Driven. See Turbo Generator.

Gibe. A metal fitting that holds a member in place or presses two members together.

Gig. A pulling or row boat of fine model and good length used principally for the convenience of the shipmaster in the performance of his duties between the ship and the shore.

Gilders. Decorators in gilt or gold leaf.

Giguy. A designation for a makeshift contrivance on board ship; also a term applied by sailors to anything whose name is unknown to them.

Gimbals. A device by which a ship’s compass, chronometer, etc., are suspended in a constant horizontal position irrespective of the rolling and pitching of the vessel. It consists of two concentric brass hoops or rings whose diameters are pivoted at right angles to each other on knife-edge bearings.

Gin Blocks. See Blocks, Gin.

Girder. On ships this term is generally applied to continuous beams running in a fore and aft direction under the decks. They are used in connection with stanchions for the purpose of supporting the decks and binding the deck beams together. This term is sometimes uses to designate the longitudinal in the double bottom.

Girder, Boiler. See Boiler Girder.

Girder, Deck. A term applied to a continuous beam running in a fore and aft direction under, and attached to, the deck beams. Also applied to a continuous range of intercostal plates and bars running fore and aft between deck beams. In deciding the height between decks the depth of the girders should be considered so that sufficient head room will be provided for.

Girder Equivalent. See Equivalent, Girder.

Girder, Intercostal. A term applied to a range of short plates fitted between and attached to continuous structural members.

Girder, Longitudinal. See Longitudinal Girder.

Girder, Ship’s (Strength). That portion of a ship’s hull structure which is composed of continuous, longitudinal members, whose material, location and connection to other portions of the structure are such that they efficiently resist the forces which tend to produce hogging or sagging. The principal members falling within the above definition are longitudinal framing, shell plating, inner bottom plating, longitudinal bulkheads and decks.

Girders, Side. See Stringer, Side.

Girder, Wing. See Margin Plate.

Girdle. Extra planking fitted over the Wales in a wooden ship.

Girtband. Sometimes termed bellyband, A strip of canvas worked across the middle portion of a sail to provide additional strength.

Girth. The distance measured on any frame line from the intersection of the upper deck with the side around the body of the vessel to the corresponding point on the opposite side.

Gland, Stern Tube. See Stern Tube Gland.

Globe Valve. See Valve, Globe.

Glue, Marine. A preparation of pine, coal tar or asphalt pitch used to fill the crevices between the planks of a wood deck to prevent water and dirt from leaking through.

Gooseneck. A fitting used to attach and support a cargo boom. A short piece of pipe, used as a ventilator, one end of which is given a 180° bend and the other end attached to a deck over an opening equal to the diameter of the pipe. Also applied to pipes and fittings in which a large bend or curve is worked.

Gorget. A crescent-shaped ornamental plate in gilt copper, worn round the neck by officers of the French Navy in full uniform.

Gouge. A tool with a half round cutting edge used to cut grooves.

Governing. The process of controlling automatically the speed of the engine under varying loads.

Governor. An apparatus or mechanism designed to eliminate great increases in engine speed due to propeller emergency. There are various types of governors for marine engines. None is entirely satisfactory because of tardy operation. Modern practice favors a form of governor which depends upon change of engine speed for its impulse.

Governor, Pump. A pressure controlling valve for governing pumps for fresh or salt water, oil, ammonia, air, etc.

Grab Stand. A piece of apparatus designed to hold a drilling machine when in operation.

Grade Line. An established reference line from which measurements are taken to any point.

Grain. A term applied to the texture or fibers of wood.

Grain Measure. A term used where the capacity of a cargo hold is measured to the shell of the vessel instead of to the inside of the frames or cargo battens.

Grain, Straight. A term applied where the grain runs parallel or nearly so to the face of the board.

Grain, Vertical or Edge. A term applied where the grain of the wood is near or at right angles to the face of the board.

Granny Knot. See Knot, Granny.

Grapnel. An implement having four prongs or hooks radiating from a common shank, fitted with a ring in the end of the latter and used as an anchor for small boats, for the purpose of recovering objects dropped overboard, for securing one vessel to another in boarding, or to make fast a towline to a burning vessel, hooking on to lines, etc. Also known as Grappling Iron.

Grapnel Line. A line bent to a grapnel, sometimes tailed with a length of chain next to the grapnel in order that it may not be burned away in towing a burning vessel or severed by the crew in boarding a hostile vessel.

Graphometer. A surveying instrument for measuring angles, derived from the Circumferentor, invented about 1696, although a plan for the first of the type, a circumferentor with graduated semi-circle, was published in France by Philippe Danfrie a hundred years before.

Grappling Irons. See Grapnel.

Grate, Fire Grate. A type of cast iron grating made up of heavy portable cast iron bars and bearers installed in the furnace. It is used to support the burning fuel.

Grate Bars. These bars support the fire in a boiler furnace and are usually made of cast iron. The bars are generally rectangular in cross section with the long side vertical and somewhat deeper in the center than at the ends. Lugs are cast on the sides to provide an air space between bars about equal to their thickness and they are commonly cast in pairs. A shallow groove running along the top of early bar will aid in keeping down the adhesion of clinkers, The grate bars are usually fitted in two lengths set to slope slightly toward the rear of the furnace and are supported in the front and rear by the furnace structure and in the center by a bearing bar.

Grate Bearer. A support for boiler grate bars, usually made of cast iron.

Grate Surface, Boiler. See Boiler Grate Surface.

Grated Hatch. See Hatch, Grated.

Grating, Fantail. A lattice work, made of wood, fitted at the after end of tug boats. It is built about eighteen inches above the deck and extends forward for a distance of about twelve feet. This grating forms a good drainage platform for stowing hawsers and towing gear when they are not in use.

Grating, wood. A lattice work constituting of two systems of wood bars running at right angles to each other. One system is usually mortised into the other to form a flush surface. Gratings are used as drainage platforms on the bridges, bath rooms, cold storage spaces, etc. They are generally made up in sections in sizes convenient for handling. Simple gratings are also often made by securing a number of small square strips of wood together with bolts or rivets, small blocks being inserted between the strips in way of the rivets to act as separators.

Gratings, Flooring, Hatchway, Walkway, Ladder Steps. A structure of metal bars so arranged as to give a support or footing over an opening, while still providing spaces between the members for the passage of light and the circulation of air. For large openings it is usually built up in panels of comparatively small size grouped on a supporting frame. For small openings it may be made in one section of the proper size. The most common applications for gratings in marine construction are for covering fair-weather and boiler hatches, floors for oil fired boiler rooms, walkways, and galleries in the engine and boiler rooms, ladder steps, etc. One of the oldest forms of grating consists of metal bars set on edge, punched or drilled at intervals, and strung on rods with short spacers of pipe placed intercostally between bars to maintain the opening. Another form of grating consists of a frame of flat bars set on edge with holes punched or drilled at short intervals in two opposite sides to receive the ends of square or round rods or flat bars set on edge. The ends of any of these types of closely spaced cross bars are turned down to form a shoulder and to fit the holes in the frame bars. The holes in the frame bars are usually countersunk on the outer side, allowing the ends of the grating rods or bars to be riveted up to a flush surface. A light and strong type of grating consists of alternate straight and corrugated or reticuline bars set on edge and solidly riveted together. To construct this grating the corrugated or reticuline bars are pressed to shape, after which they and the straight bars are carefully punched to templates, then assembled in alignment, and a heavy rivet formed in each hole. This grating possesses excellent non-slipping qualities and is also suitable for trucking.

Gratings, Fidley. See Fidley Gratings.

Gratings, Hatch. Gratings usually constructed of wood, fitted over hatch openings. They are particularly desirable where hatch covers are removed or opened.

Gratings, Skylight. See Skylight Gratings.

Graving Dock. See Dry Dock, Graving.

Graving Pieces. Small pieces of wood fitted into the deck where the surface has been injured or decayed, and where it is not deemed feasible or practicable to renew the entire piece.

Grease Cup. A receptacle designed to hold grease and used where a positive feed is required for lubricating machinery.

Grease, Launching. See Launching Grease.

Greaser. A member of a ship’s boiler room force who cleans out the bilges and boiler flues and performs other work of the lower grade.

Gridiron. Heavy sleepers or timbers fastened to the tops of piling at or near the bottom of a river or harbor where there is a tide. Boats or scows are placed on the gridiron at high tide so that they may be done on their sides or bottom at low tide. Scows are also placed on gridirons so that they will remain at the level while they are being loaded or unloaded.

Grill Work. An ornamental lattice work.

Grinding Machine. A machine employing an abrasive wheel for any kind of grinding, such as sharpening or forming tools, truing machine centers, finishing machine surfaces, etc. Grinding machines are generally electric motor or belt driven, but pneumatic machines are built in both the portable and bench types.

Grinders. Men who remove excess material by means of an emery wheel

Grindstone. An abrasive wheel generally used for sharpening wood working tools.

Gripe. A curved piece of timber joining the forward end of the keel and the lower end of the cutwater.

Gripe, Release. Fittings and chain assembled together for holding purposes which can be easily parted at a moment’s notice.

Gripes, Boat. An arrangement for holding small boats securely in their stowage chocks. They are made up of lashings or chains fitted on one end with a turnbuckle or pelican hook and a shackle for attachment to a pad eye on the deck and on the other end with a flat bar hook for attachment to the gunwale of the boat.

Grommet. A ring of fiber usually soaked in red lead or some other packing material and used under the heads of bolts and nuts to preserve tightness. Also applied to washers or eyelets of metal.

Gross Tonnage. See Tonnage, Gross.

Ground Tackle. A general term for all anchors, cables, buoys, ropes, purchases, etc., used in the operation of mooring and unmooring a ship.

Gudgeons, Rudder. Lugs cast or forged on the stern post for the purpose of hanging and hinging the rudder. They are bored to form a bearing for the rudder pintles and are usually bushed with a lignum vitae or white metal bearing surface.

Guess Warp. A hawser carried out in a small boat and bent to a distant fixed object in order to warp the vessel toward it. The name originated from the necessity of having to judge the distance by the eye.

Gun Tackle. A purchase consisting of two single blocks and a length of rope.

Gunboat. A war vessel designed principally for use on a foreign station. Its principal characteristics are moderate displacement, moderate speed, good cruising radius, moderate draft, light battery, comfort for the personnel, and robust construction.

Gunter’s Scale. A wooded of brass ruler 1-2ft. long, engraved with the scales of chords, logarithms, trigonometry foundations and the like, used in navigation and for surveying. It was a predecessor of the slide rule.

Gunwale. A term applied to the line where an upper deck stringer intersects the shell.

Gunwale Bar. A term applied to the bar connecting a stringer plate on a weather deck to the sheer strake.

Gunwale, Bridge. The line where the bridge deck stringer intersects the shell.

Gunwale, Forecastle. The intersection of the forecastle deck stringer with the shell.

Gunwale, Poop. The line where the poop deck stringer intersects the shell.

Gunwale, Quarter Deck. The line where the quarter deck intersects the shell.

Gunwale, Rounded. A term applied where the shell and frames are rounded into a deck.

Gunwale Stringer. See Stringer, Gunwale.

Gusset; Gusset Plate. A term applied to a horizontal bracket. It is used as additional attachment for strong hold beams to stringers, the bottom of side frames, to the tank top, etc.

Guys. Wire or hemp ropes, or chains to support booms, davits, etc., laterally. They may consist of single lines or purchases, leading from the davit head or boom end to the deck. In the case of single lines they are either lashed to eyes or rings or else fitted with turnbuckles and hooked or shackled to deck connections. Guys are employed in pairs. Where a span is fitted between two booms or davits one pair only is required for the two. Guys to booms that carry sails are sometimes known as backropes.

Gypsy. A small auxiliary drum usually fitted on one or both ends of a winch or windlass.

Gyroscope. Strictly, any rotating mass. Usually a wheel so constructed as to demonstrate or utilize gyroscopic action.

Gyroscopic Compass. See Compass, Gyroscopic.

Gyroscopic Stabilizer. See Stabilizer, Gyroscopic.


LEGAL NOTE: Please read this fine print

This glossary is copyright Bruce Beveridge and TRMA. It is not to be used or altered in any other format(public webpages, published print or for the viewing of an audience). Please be aware that if any part of this glossary is found being used else ware, the appropriate actions will be taken.

If you would like to use any part of the glossary, you must ask for permission first. Chances are, we will say yes, but we just need to know where it is on the web and we require a link back to our page if you use any part of the glossary.

Back to the main glossary page
Or go back to our home page