Glossary
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TermDefinition
- General Nautical Terminology Gaff
A spar attached to a mast, used to support the upper edge of a fore-and-aft sail, such as a gaff rigged mainsail or topsail.
A gaff is an...
More Details - General Nautical Terminology Gaff Rig
A sailing rig where the sail is four-sided and controlled by a spar (the gaff) at its top, which is hoisted at an angle to the mast.
A gaff...
More Details - Weather (Meteorology) Gale
Beaufort Scale - Force 8 (Gale Force 8)
A gale refers to a strong wind between 34 to 40 knots (39 to 46 mph or 63 to 74 km/h) on the Beaufort...
More Details - General Nautical Terminology, Parts of a Boat Galley
The kitchen or cooking area on a ship or boat, typically compact and designed for efficient use of space.
Unlike a kitchen in a house, the...
More Details - Flag / Pennant, Signals & Communication Code Flag Golf (G)

The International Maritime Signal Flag Golf.
Meaning
I require a pilot.
More Details
By fishing vessels: I am hauling nets.
If appended by a Numeral... - General Nautical Terminology GDOP
A measure in marine navigation that quantifies the effect of satellite geometry on the accuracy of position determination. It is a factor used to...
More Details - General Nautical Terminology, Parts of a Boat Gelcoat
A specialised resin-based coating applied to the surface of fibreglass boats to provide a smooth, durable, and protective outer layer.
Gelcoat...
More Details - Organisation General Lighthouse Authorities (GLA)
A term that collectively refers to the three organisations responsible for maintaining maritime navigation aids—such as lighthouses, buoys, and...
More Details - General Nautical Terminology Genoa
A large foresail that overlaps the mainsail, commonly used on sailing yachts to improve speed and performance in light to moderate winds.
A...
More Details - General Nautical Terminology Geometric Dilution of Precision (GDOP)
A measure in marine navigation that quantifies the effect of satellite geometry on the accuracy of position determination. It is a factor used to...
More Details - General Nautical Terminology, Weather (Meteorology) German Bight
Sea area of the Met Office Shipping Forecast. Located in the southeastern North Sea, off the coast of northern Germany and the...
More Details - General Nautical Terminology, Weather (Meteorology) GFS
A weather model developed by the National Centers for Environmental Prediction (NCEP) that provides global weather forecasts by simulating the...
More Details - General Nautical Terminology Gimbal
A pivoted support that allows an object, such as a compass or a stove, to remain level regardless of the motion of the vessel.
A gimbal is a...
More Details - General Nautical Terminology Give Way
In a collision situation, one or more vessels are defined as Give Way. The Give Way vessel should alter its course to concede passage to another...
More Details - General Nautical Terminology Give Way VesselThe vessel whose duty it is to keep clear of another, she should take early and substantial action to avoid a collision
- Organisation GLA
A term that collectively refers to the three organisations responsible for maintaining maritime navigation aids—such as lighthouses, buoys, and...
More Details - General Nautical Terminology Glass Reinforced Plastic (GRP)
A composite material made of a polymer matrix reinforced with fine glass fibres, commonly used in marine applications for its strength,...
More Details - Flag Semaphore, Signals & Communication Letter G (Flag Semaphore)

This shape represents the Letter G (Flag Semaphore) and the Number 7 (Flag Semaphore).
- Morse Code, Signals & Communication Letter G (Morse Code)
International Morse Code sequence representing the letter G.
- General Nautical Terminology, Weather (Meteorology) Global Forecast System (GFS)
A weather model developed by the National Centers for Environmental Prediction (NCEP) that provides global weather forecasts by simulating the...
More Details - General Nautical Terminology, Safety Global Maritime Distress and Safety System (GMDSS)
An internationally agreed-upon set of safety procedures, communication protocols, and equipment designed to ensure that ships at sea can send and...
More Details - Signals & Communication Global Maritime Distress and Safety System Sea Areas
A map of the UK indicating the 3 sea areas around the coast and the coast of nearby European countries. White pointers indicate Medium Frequency...
More Details - General Nautical Terminology, Navigation Global Navigation Satellite System (GNSS)
The collective set of systems that enables positioning devices to calculate latitude & longitude. The system includes solutions including the GPS...
More Details - General Nautical Terminology Global Positioning System (GPS)
The US-based system of satellites, able to determine the latitude and longitude of a receiver on Earth by calculating the time difference for...
More Details - General Nautical Terminology, Safety GMDSS
An internationally agreed-upon set of safety procedures, communication protocols, and equipment designed to ensure that ships at sea can send and...
More Details - General Nautical Terminology, Navigation GMT
The mean solar time at the Prime Meridian in Greenwich, London, used as a global time standard.
Greenwich Mean Time (GMT) is a timekeeping...
More Details - General Nautical Terminology, Navigation Gnomonic Projection
A type of map projection where the surface of the Earth is projected onto a plane from the centre of the globe, causing great circles to appear...
More Details - General Nautical Terminology, Navigation GNSS
The collective set of systems that enables positioning devices to calculate latitude & longitude. The system includes solutions including the GPS...
More Details - General Nautical Terminology Go AboutTo change tack by altering course to bring the wind on the other side
- General Nautical Terminology Going AsternWhen going backwards through the water you may hear the skipper say: "I am going astern".
- Phonetic Alphabet, Signals & Communication Golf
Pronounced: GOLF
The term for the letter G in the NATO Phonetic Alphabet.
- General Nautical Terminology Gooseneck
A pivotal fitting on a sailing vessel that connects the boom to the mast, allowing for controlled movement in multiple directions.
The...
More Details - General Nautical Terminology Goose-winged
A sailing configuration where a fore-and-aft rigged vessel's sails are set on opposite sides of the boat, typically with the mainsail on one side...
More Details - General Nautical Terminology GPS
The US-based system of satellites, able to determine the latitude and longitude of a receiver on Earth by calculating the time difference for...
More Details - General Nautical Terminology Grab RailRails fitted above and below decks to grab at when the vessel heels
- General Nautical Terminology, Navigation Greenwich Mean Time (GMT)
The mean solar time at the Prime Meridian in Greenwich, London, used as a global time standard.
Greenwich Mean Time (GMT) is a timekeeping...
More Details - General Nautical Terminology, Weather (Meteorology) GRIB
A type of data format used in oceanography and meteorology to represent gridded data in a binary form for efficient storage and...
More Details - General Nautical Terminology, Weather (Meteorology) GRIdded Binary (GRIB)
A type of data format used in oceanography and meteorology to represent gridded data in a binary form for efficient storage and...
More Details - General Nautical Terminology GroundA general term for the anchors, cables and all the gear required when anchoring
- General Nautical Terminology GRP
A composite material made of a polymer matrix reinforced with fine glass fibres, commonly used in marine applications for its strength,...
More Details - General Nautical Terminology Guard RailSafety line fitted round the vessel to prevent the crew falling overboard
- General Nautical Terminology Guardrail
A safety barrier installed along the edges of a vessel’s deck to prevent crew or passengers from falling overboard.
This essential feature on...
More Details - General Nautical Terminology Gunwale
The upper edge or rim of a boat's side, often serving as a structural reinforcement and a mounting point for fittings or equipment.
The term...
More Details - General Nautical Terminology Guy
A rope, wire, or chain used to stabilise or secure a mast, spar, or other structure on a vessel by counteracting lateral forces.
A guy is a...
More Details - General Nautical Terminology Gybe
A gybe (jibe) is a sailing manoeuvre where a boat changes direction by turning its stern through the wind. During a gybe, the wind crosses over...
More Details - General Nautical Terminology Gybe-oh!The call to indicate that the helm is being put across to gybe

