1. The spar that holds the upper edge of a four-sided fore-and-aft mounted sail.
2. A hook on a long pole to haul fish in.
Gaff rigged: A boat rigged with a four-sided fore-and-aft sail with its upper edge supported by a spar or gaff which extends aft from the mast.
Gaff vang: A line rigged to the end of a gaff and used to adjust a gaff sail's trim.
Gam: A meeting of two (or more) whaling ships at sea. The ships each send out a boat to the other, and the two captains meet on one ship, while the two chief mates meet on the other.
Gammon iron: The bow fitting which clamps the bowsprit to the stem.
Galley: the kitchen of the ship
Gangplank: A movable bridge used in boarding or leaving a ship at a pier; also known as a "brow".
Gangway: An opening in the bulwark of the ship to allow passengers to board or leave the ship.
Garbling: The (illegal) practice of mixing cargo with garbage.
Garboard: The strake closest to the keel (from Dutch gaarboard).
Garboard planks: The planks immediately either side of the keel.
Gash: Any refuse or rubbish which is discarded into a refuse container or dustbin which is known as "gash fanny" (South African Navy).
Gash Fanny: Refuse container or dustbin.
Gennaker: A large, lightweight sail used for sailing a fore-and-aft rig down or across the wind, intermediate between a genoa and a spinnaker.
Genoa or genny (both /?d??ni/): A large jib, strongly overlapping the mainmast.
Ghost: To sail slowly when there is apparently no wind.
Gibe: See gybe.
Gin-pole: A pole that is attached perpendicular to the mast, to be used as a lever for raising the mast. Also jin-pole.
Give-way (vessel): Where two vessels are approaching one another so as to involve a risk of collision, this is the vessel which is directed to keep out of the way of the other.
Glass: A marine barometer. (Older barometers used mercury-filled glass tubes to measure and indicate barometric pressure.)
Global Positioning System: (GPS) A satellite based radionavigation system providing continuous worldwide coverage. It provides navigation, position, and timing information to air, marine, and land users.
Go-fast boat, is a small, fast boat designed with a long narrow platform and a planing hull to enable it to reach high speeds – also called ‘a rum-runner’, or, more recently, ‘a cigarette boat’.
Going about or tacking: Changing from one tack to another by going through the wind (see also gybe).
Gooseneck: Fitting that attaches the boom to the mast, allowing it to move freely.
Goosewinged: Of a fore-and-aft rigged vessel sailing directly away from the wind, with the sails set on opposite sides of the vessel—for example with the mainsail to port and the jib to starboard, to maximize the amount of canvas exposed to the wind. Also see running.
Grapeshot: Small balls of lead fired from a cannon, analogous to shotgun shot but on a larger scale. Similar to canister shot but with larger individual shot. Used to injure personnel and damage rigging more than to cause structural damage.
Grave: To clean a ship’s bottom.
Gripe: Temporary eye in a line(rope).
Grog: Watered-down pusser's rum consisting of half a gill with equal part of water, issued to all seamen over twenty. (CPOs and POs were issued with neat rum) From the British Admiral Vernon who, in 1740, ordered the men's ration of rum to be watered down. He was called "Old Grogram" because he often wore a grogram coat, and the watered rum came to be called 'grog'. Often used (illegally) as currency in exchange for favours in quantities prescribed as 'sippers' and 'gulpers'. Additional issues of grog were made on the command 'splice the mainbrace' for celebrations or as a reward for performing especially onerous duties. The RN discontinued the practice of issuing rum in 1970. A sailor might repay a colleague for a favour by giving him part or all of his grog ration, ranging from "sippers" (a small amount) via "gulpers" (a larger quantity) to "grounders" (the entire tot).
Groggy: Drunk from having consumed a lot of grog.
Ground: The bed of the sea.
Grounding: When a ship (while afloat) touches the bed of the sea, or goes "aground" (qv).
Gunport: The opening in the side of the ship or in a turret through which the gun fires or protrudes.
Gunner's daughter: see kissing the gunner's daughter.
Gunwale (/???n?l/): Upper edge of the hull.
Gybe or jibe (both /?d?a?b/): To change from one tack to the other away from the wind, with the stern of the vessel turning through the wind. (See also going about and wearing ship.)