Glossary Archive

The CADET mnemonic can help remember the corrections needed when converting between True North and Compass North bearings. It assists in adjusting for magnetic variation and deviation, which is essential for accurate navigation. Here’s what each letter in CADET represents: CADET Mnemonic Breakdown C — Compass: Start with the compass bearing, the direction the compass...

A unique identifier assigned to a vessel or maritime station for communication purposes, typically used in radio transmissions. A call sign is a critical component of maritime communication, serving as a vessel's unique identifier when transmitting over radio frequencies. National or international regulatory bodies, such as the International Telecommunication Union (ITU), assign these identifiers. They...

A mechanical device with spring-loaded, opposing cams that grip a rope or line to hold it securely while allowing for quick adjustments.  A cam cleat consists of two spring-loaded, serrated cams that rotate inward to grip a line when it is pulled taut. The design allows for easy engagement and release by simply pulling or...

Cancel (or Disregard) informs the receiver to disregard the previous message or cancel the signalling. There is no specific attachment to this signal, so context and some interpretation will be required unless the sender specifics by spelling out the cancel message.

When a ship or boat overturns, exposing the keel or centre board

Cardinal Bearings are the main points on a compass, expressed by their name. There are four main cardinal points, North, South, East, and West which are also known by their first letters: N, S, E, and W. There are also four cardinal half points between each main cardinal point: North East, South East, South West,...

Buoy or pillar placed at North, East, South or West side of an obstruction to warn vessels away. Cardinal marks indicate that the deepest water in the area lies to the named side of the mark. They are used in conjunction with the compass to indicate the direction from the mark in which the deepest...

To let go a rope or line

A vessel with two hulls.

A navigational situation where two vessels maintain the same relative bearing to each other while the distance between them diminishes, often indicating a potential risk of collision. Constant bearing, decreasing range (CBDR) is a critical concept in maritime navigation, used to assess collision risks between vessels at sea. When two vessels are on a CBDR...