Glossary Archive

A method of transmitting information by varying the strength (amplitude) of a carrier wave in proportion to the signal being sent. Amplitude Modulation (AM) is a technique used in marine radio communications to encode audio or data signals onto a carrier wave by altering its amplitude. The frequency of the carrier remains constant, but the...

A US-based organisation that provides sailing education, certification, and accreditation for sailing schools and instructors.  The American Sailing Association (ASA) was founded in 1983 to promote safe and competent recreational sailing through standardised education and certification. It offers a structured curriculum covering various skill levels, from basic keelboat sailing to advanced offshore passagemaking. ASA-certified schools...

The central part of a vessel, both longitudinally and laterally, located between the bow and stern. Amidships is a crucial term in nautical terminology, denoting the middle section of a ship or boat. This area is generally considered the most stable part of a vessel, as it is equidistant from both the bow (front) and...

A method of transmitting information by varying the strength (amplitude) of a carrier wave in proportion to the signal being sent. Amplitude Modulation (AM) is a technique used in marine radio communications to encode audio or data signals onto a carrier wave by altering its amplitude. The frequency of the carrier remains constant, but the...

A heavy object, typically made of metal, designed to grip the seabed and hold a vessel in position. An anchor is a crucial piece of equipment on any vessel, used to prevent the boat from drifting due to wind or currents. It works by embedding itself into the seabed, providing resistance that keeps the vessel...

A designated area where a vessel can be securely anchored, typically marked on nautical charts and chosen for its safe holding ground and protection from adverse conditions. An anchorage is a specific location, often designated on nautical charts, where vessels can drop anchor and remain stationary. These areas are typically chosen for their favourable seabed...

The moment when an anchor has been lifted off the seabed and is no longer holding the vessel in place. The term "anchor aweigh" is a traditional nautical expression used to describe the precise moment when an anchor has been hoisted off the seabed and is no longer securing the vessel. This is a critical...

A black spherical day shape hoisted on a vessel to signal that it is anchored during daylight hours. An anchor ball is a crucial piece of maritime signalling equipment used to indicate that a vessel is anchored. It is a black, spherical object, typically made of durable material, and is hoisted in a prominent position,...

A small floating marker attached to an anchor to indicate its location on the seabed. An anchor buoy is a vital piece of equipment used in marine operations to mark the position of an anchor on the seabed. It is typically a brightly coloured, highly visible float attached to the anchor by a line or...

A heavy-duty rope, chain, or wire used to secure a vessel to its anchor, ensuring it remains stationary in the water. An anchor cable is a critical component of a vessel's anchoring system, designed to connect the anchor to the ship or boat securely. Traditionally, these cables were made of natural fibre ropes, but modern...