Glossary Archive

The US-based system of satellites, able to determine the latitude and longitude of a receiver on Earth by calculating the time difference for signals from different satellites to reach the receiver. GPS is part of the GNSS solution for positioning used by chart plotters and other positioning devices.

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 mean solar time at the Prime Meridian in Greenwich, London, used as a global time standard. Greenwich Mean Time (GMT) is a timekeeping system that started at the Royal Observatory in Greenwich, London, and acts as a reference point for global time zones. It is based on the mean solar time at the Prime...

A chart projection of part of a hemisphere showing the earth's grid projected by radials from a point at the centre of the sphere onto a plane so that all straight lines represent arcs of great circles thereby making this projection valuable for navigation when used in conjunction with the Mercator projection. Particularly used on...

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.

To change tack by altering course to bring the wind on the other side

When going backwards through the water you may hear the skipper say: "I am going astern".

Pronounced: GOLF The term for the letter G in the NATO Phonetic Alphabet.

A gooseneck is a fitting on a sailboat that connects the boom to the mast. It allows the boom to pivot and move freely, positioning the sail correctly for optimal performance. The gooseneck is an essential component of the rigging system on a sailboat.

Having one sail set on each side of the boat when running directly downwind.