Glossary Archive

A system of coloured and white lights displayed on a vessel to indicate its position, heading, and status to other vessels, especially during low visibility or nighttime. Navigation lights are an essential safety feature on all vessels, from small recreational boats to large commercial ships, and are mandated by international maritime regulations, such as the...

A maritime communication system used for the automatic broadcast of navigational and meteorological warnings, forecasts, and urgent safety information to ships. Navtex, short for "Navigational Telex," is integral to the Global Maritime Distress and Safety System (GMDSS). It operates on medium frequencies (518 kHz internationally for English messages and 490 kHz for local language broadcasts)...

The International Maritime Signal Flag November. Meaning Negative.

A radio transmitter at a fixed location that emits signals in all directions, used in marine navigation to help vessels determine their position relative to the beacon. A Non-Directional Beacon (NDB) is a fundamental navigational aid in the maritime world, providing mariners with a reliable method to ascertain their position and course. Unlike directional or...

The difference in height between HW and LW on a Mean (average) neap tide.

When the difference between high and low water is at its smallest, typically occurring twice a month during the first and third quarters of the moon. A neap tide is a natural tidal phenomenon that occurs when the gravitational forces of the moon and the sun are at right angles relative to the Earth. This...

Sometimes used to describe wind strength approaching a Gale.

The Northern Lighthouse Board is a maritime organisation responsible for maintaining lighthouses and navigation aids in Scotland and the Isle of Man. Established: The Northern Lighthouse Board was established in 1786 and serves a similar purpose to Trinity House but specifically covers Scotland and the Isle of Man. Responsibilities: NLB is responsible for the operation...

Flag semaphore indicating the letter N.

International Morse Code sequence representing the letter N.