Glossary

A spar that supports the head of a four-sided fore-and-aft sail.

The gaff is attached near its forward end to the mast and extends aft and...

A fore-and-aft rig in which a gaff supports the head of a generally four-sided sail.

The gaff’s forward end lies against or near the mast and...

A Beaufort force 8 wind, with a mean speed of 34 to 40 knots.

At sea, a gale produces moderately high waves, spindrift and well-defined...

An official warning that gale-force winds are expected or occurring in a specified marine area.

Thresholds and wording follow the issuing...

The compartment or designated area aboard a vessel where food is prepared and cooked.

A galley may range from a small counter with a single...

Electrochemical corrosion that occurs when dissimilar metals are electrically connected in an electrolyte such as seawater.

The less noble...

An International Code of Signals flag whose single-letter meaning is “I require a pilot.”.

The Golf flag may be displayed alone to convey this...

A dimensionless GNSS geometry factor combining three-dimensional position and receiver-clock uncertainty.

GDOP reflects how the relative...

A pigmented surface resin applied to the mould before a fibre-reinforced composite hull or component is laminated.

Gelcoat is commonly based...

The three statutory bodies providing general aids to marine navigation around the United Kingdom and Ireland.

They are Trinity House, the...

An overlapping headsail whose clew extends abaft the mast when sheeted.

Genoa size is conventionally expressed by comparing its luff...

A mathematical reference framework used to define positions on or near the Earth.

A datum specifies an ellipsoid and its relationship to the...

A dimensionless GNSS geometry factor combining three-dimensional position and receiver-clock uncertainty.

GDOP reflects how the relative...

A named sea area used in the UK Shipping Forecast, in the southeastern North Sea off Germany and the Netherlands.

The name describes the broad...

Germany's navigable coastal and inland waters governed by national and local navigation requirements.

They include tidal estuaries, canals,...

The United States National Centers for Environmental Prediction’s operational global numerical weather prediction system.

GFS assimilates...

A pivoted mounting that allows supported equipment to remain approximately level as a vessel heels or pitches.

One or more pivot axes let a...

To take the action required to keep clear of another vessel in a collision-avoidance situation.

Where the collision regulations require a...

The vessel required by the applicable collision regulations to keep out of the way of another vessel in a particular encounter.

This is a role...

The three statutory bodies providing general aids to marine navigation around the United Kingdom and Ireland.

They are Trinity House, the...