Glossary Archive

A large foresail that overlaps the mainsail, commonly used on sailing yachts to improve speed and performance in light to moderate winds. A Genoa, also known as a "Genny," is a type of headsail used on sailing vessels, particularly yachts. It is a variation of the jib sail but is significantly larger, often extending beyond...

A measure in marine navigation that quantifies the effect of satellite geometry on the accuracy of position determination. It is a factor used to assess the quality of the satellite configuration in relation to the receiver's position. A low GDOP value indicates good satellite geometry, resulting in more accurate position fixes, while a high GDOP...

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 vessel. Every vessel directed to keep out of the way of another vessel shall, so far as possible, take early and substantial action to keep well clear.

The vessel whose duty it is to keep clear of another, she should take early and substantial action to avoid a collision

A term that collectively refers to the three organisations responsible for maintaining maritime navigation aids—such as lighthouses, buoys, and beacons—in the waters surrounding the United Kingdom and Ireland. These organisations ensure safe navigation for all mariners in their respective regions and work together to standardise navigational practices across British and Irish waters. The Three General...

A fibre reinforced polymer made of a plastic matrix reinforced by fine fibres of glass. GRP is a lightweight, extremely strong, and robust material.

This shape represents the Letter G (Flag Semaphore) and the Number 7 (Flag Semaphore).

International Morse Code sequence representing the letter G.

An internationally agreed-upon set of safety procedures, communication protocols, and equipment designed to ensure that ships at sea can send and receive distress signals and safety information. The Global Maritime Distress and Safety System (GMDSS) was established by the International Maritime Organization (IMO) to enhance maritime safety and facilitate the efficient coordination of search and...

The collective set of systems that enables positioning devices to calculate latitude & longitude. The system includes solutions including the GPS (US) and GLONASS (Russian) network of satellites.