Glossary Archive

The universally recognised distress signal used in maritime communication to indicate an emergency requiring immediate assistance. The German government introduced it as part of the international Morse code in 1905. On July 1, 1908, following the International Radiotelegraph Convention of 1906, SOS was adopted globally as the standard distress signal. SOS was proposed in 1906The...

To measure the depth of water

The depth of water below chart datum

Sea area of the Met Office Shipping Forecast. Located southeast of Iceland in the North Atlantic. Southeast Iceland covers waters renamed from “Iceland” in 1955, southeast of the island. Influenced by the Gulf Stream, it is milder than the open Atlantic but still sees frequent gales (Force 8–10) and large swells; a January 1995 storm...

Sea area of the Met Office Shipping Forecast. Situated in the North Sea, south of Utsira Island off the west coast of Norway. Also named for Utsira Island, South Utsire covers the southern part of the adjacent waters. While slightly more sheltered than North Utsire, it still sees frequent winter gales (Force 8) and rough...

A waterproof oilskin hat with a broad brim

This shape indicates a space, usually between words. The same shape is also used for Rest (Flag Semaphore) & Ready (Flag Semaphore).

Any long, sturdy pole or beam used on a ship to support sails, rigging, or other equipment. Spars are typically made of wood, metal, or composite materials and are essential to a ship’s rigging system. There are several types of spars on a vessel, each serving different functions in relation to the sails and mast....

The speed made good over the ground; that is , the boat speed corrected for tidal stream and leeway

The actual velocity of a vessel relative to the Earth's surface, accounting for the effects of currents, tides, and other environmental factors.  Speed Over Ground (SOG) is a critical navigational term in maritime operations, representing the true speed at which a vessel moves over the Earth's surface. Unlike Speed Through Water (STW), which measures the...