Glossary Archive

The organisation responsible for search and rescue operations in UK waters. His Majesty's Coastguard (HMCG) is a section of the MCA responsible for initiating and coordinating all maritime search and rescue within the UK Maritime Search and Rescue Region. This includes mobilising, organising and tasking adequate resources and assets, such as the RNLI or coastguard helicopters, to respond to persons in distress...

The small triangular area formed when three position lines on a nautical chart intersect but do not meet at a single point, indicating a degree of uncertainty in the vessel's position. The term "Cocked Hat" originates from traditional navigation practices, where sailors would use celestial or terrestrial observations to determine their position at sea. When...

The area of a boat, typically located towards the stern, where the helm, controls, and seating for the crew are situated. The cockpit of a boat is a critical operational area, usually found in the aft (rear) section, though on some vessels, it can be positioned amidships. It serves as the command centre for the...

A lightweight, high-performance sail designed for close-reaching angles, typically used in light wind conditions to maximise boat speed.  A Code Zero is a specialised sail that bridges the gap between a traditional genoa and an asymmetric spinnaker. It is designed for use in light to moderate winds, typically between 5 and 15 knots, and is...

The actual path a vessel follows over the surface of the Earth, as opposed to its heading or intended course. Course Over Ground (COG) is a critical concept in navigation, representing the true direction in which a vessel is moving relative to the Earth's surface. It is often measured in degrees from true north, and...

The course of a vessel which, if maintained relative to that of another would result in a collision

The internationally agreed rules designed to prevent collisions at sea by setting out navigation procedures, responsibilities, and conduct for vessels. The Collision Regulations, formally known as the International Regulations for Preventing Collisions at Sea (IRPCS), are a set of rules established by the International Maritime Organization (IMO) to standardise navigational behaviour and ensure the safe...

The internationally agreed rules designed to prevent collisions at sea by setting out navigation procedures, responsibilities, and conduct for vessels. The Collision Regulations, formally known as the International Regulations for Preventing Collisions at Sea (IRPCS), are a set of rules established by the International Maritime Organization (IMO) to standardise navigational behaviour and ensure the safe...

Irish Lights is responsible for maintaining lighthouses, buoys, beacons, and other navigation aids along the entire coast of Ireland, including both the Republic of Ireland and Northern Ireland. Established: Irish Lights was founded in 1867, though lighthouse authorities have existed in Ireland for centuries. Responsibilities: Irish Lights is responsible for maintaining lighthouses, buoys, beacons, and...

A companionway is a stairway or ladder that provides access between different levels on a boat or ship. It typically connects the main deck to the lower decks or cabins. It is an essential part of the vessel’s layout, allowing crew and passengers to move safely and efficiently throughout the ship. On a sailing vessel,...