Glossary Archive

⚓ Nautical Origin of A Clean Bill of Health: Back in the 18th and 19th centuries, when ships traveled from port to port, they could carry more than just cargo—they might also bring diseases like cholera, plague, or yellow fever. To prevent outbreaks, port authorities began requiring ships to present a “bill of health”—an official document from the last port of...

A section of water that is free from obstructions, hazards, or any other vessels. In the context of marine terminology, clear water is a term used to describe a body of water that is free from any obstructions, hazards, or other vessels. This could include anything from rocks, reefs, and sandbars to other boats, buoys,...

Refers to conditions at sea where visibility is good, the sky is mostly free of clouds, and there are no immediate threats of severe weather events. In greater detail, clear weather is a term used in marine contexts to describe optimal weather conditions for navigation and other maritime activities. This typically includes a sky that...

To disentangle a line, for example, removing it from a dock cleat when manoeuvring out of a marina. When departing from a mooring, it is good practice to give the instruction 'Clear', indicating that the line is free from its attachment and out of the water. This avoids potential entanglement in the vessel's propeller and informs...

The distance between top of mast and bridge or bottom of keel and seabed.

A fitting on a boat or dock used to secure a rope or line. A cleat is an piece of hardware found on boats, docks, and other marine structures, designed to secure lines or ropes. Typically, a cleat is made of metal, such as stainless steel or aluminium, or durable plastic, and it features two...

This shape represents the Letter C (Flag Semaphore) and the Number 3 (Flag Semaphore).

International Morse Code sequence representing the letter C.

The lower aft corner of a sail, where the foot and leech meet, and is often equipped with a grommet or cringle for attaching control lines such as the sheet. The clew is a critical component of a sail's geometry and functionality on a sailing vessel. It is one of the three corners of a...

A sailing boat's course that is as directly into the wind as possible. Close hauled is a point of sail where the boat is sailing as directly into the wind as it can, typically around 45 degrees off the wind direction. This is the closest angle to the wind that a boat can sail without...