Glossary

A line or tackle system used to adjust the angle of a jib or genoa sheet to optimise sail shape and performance, particularly when sailing off...

A bathing platform is a purpose-built area that sits at water level when the vessel is stopped. It allows easy access to and from the water. It...

A thin, flat strip of wood, plastic, or fibreglass inserted into a sail to help maintain its shape and improve performance

A batten is an...

A reinforced sleeve sewn into a sail to hold a batten, which helps maintain the sail's shape.

A batten pocket is an essential feature of many...

The International Maritime Signal Flag Bravo.

Meaning

I am taking in or discharging or carrying dangerous goods.

A fixed or floating signal, often a light or radio transmitter, used to guide mariners or mark hazards in navigable waters.

A beacon is an...

The widest part of a vessel, measured at its broadest point across the hull.

The term beam is a fundamental concept in nautical terminology,...

The point of sail where the wind is coming from directly abeam, or at a right angle to the boat's centreline. 

A beam reach is one of the most...

The direction or angle between a reference point, typically true north, and an object or destination, usually expressed in degrees.

A bearing...

The direction from a vessel's current position to a predetermined navigational point or waypoint.

In marine navigation, Bearing to Waypoint is...

A scale used for estimating and reporting wind speeds based on observed sea conditions.

British Admiral Sir Francis Beaufort developed it in...

Below deck refers to the interior spaces of a vessel located beneath the main deck or upper deck. These areas typically include crew quarters,...

A type of sail plan characterised by a triangular mainsail set aft of the mast, with the mast typically taller than the length of the boat.

A...

A loop created in the standing part of a rope.

A canvas or fabric top supported by a metal frame, typically found on boats to provide shade and protection from the sun. 

A Bimini is a...

Sea area of the Met Office Shipping Forecast. Covers the Bay of Biscay, off the west coast of France and north coast of Spain.

Covering the Bay...

This shape represents the Letter B (Flag Semaphore) and the Number 2 (Flag Semaphore).

International Morse Code sequence representing the letter B.

A type of pulley system used to change the direction of a line, rope, or cable on a boat. Blocks consist of one or more grooved wheels, called...

A horizontal spar used to extend the foot of a sail and control its angle to the wind. 

A boom is an essential part of a sailing vessel's...

A strong, cold, and dry northeasterly katabatic wind that blows from the land to the sea, particularly along the eastern Adriatic coast.

The...

Short for boatswain, the Bosun is a senior crew member responsible for the vessel's maintenance, repair, and overall operation. The bosun...

The forward part of a vessel, designed to cut through the water and reduce resistance.

The bow of a vessel is its frontmost section, typically...

A rope used to secure the bow of a vessel to a dock or another fixed object.

A bow line is a critical part of a vessel's mooring system,...

A type of knot used to form a fixed loop at the end of a rope, commonly employed in maritime settings for securing or towing.

The bowline is...

A mooring line that runs diagonally from the bow of a vessel to a fixed point on a dock, used to control forward and backward movement while...

Pronounced: BRAH-voh

The term for the letter B in the NATO Phonetic Alphabet.

A point of sail where the wind comes from behind the beam of the boat, typically at an angle of 90 to 160 degrees relative to the vessel's...

A type of claw-shaped anchor designed to provide strong holding power in a variety of seabed conditions. 

The Bruce anchor, also known as...

The direction from a vessel's current position to a predetermined navigational point or waypoint.

In marine navigation, Bearing to Waypoint is...

 A built-in bed or sleeping berth on a boat or ship, typically compact and designed to maximise space efficiency. 

A bunk is a fundamental...

A floating device anchored at a specific location in a body of water, used as a navigational aid, marker, or warning signal for vessels.

A...

A floating pyrotechnic device that emits dense, orange coloured smoke to signal distress or indicate position at sea. 

A buoyant smoke flare...

“By and large”—another classic sailing phrase that’s drifted into everyday English. Here’s the nautical story behind it:

⚓ Nautical Origin of...

Unit of measure (distance)

A cable is a unit of distance traditionally used to measure short distances at sea. It is generally considered...

The CADET mnemonic can help remember the corrections needed when converting between True North and Compass North bearings. It assists in...

A unique identifier assigned to a vessel or maritime station for communication purposes, typically used in radio transmissions.

A call sign is...

A mechanical device with spring-loaded, opposing cams that grip a rope or line to hold it securely while allowing for quick adjustments. 

A...

Cancel (or Disregard) informs the receiver to disregard the previous message or cancel the signalling. There is no specific attachment to...

Cardinal Bearings are the main points on a compass, expressed by their name. There are four main cardinal points, North, South, East, and West...

Buoy or pillar placed North, East, South or West side of an obstruction to warn vessels away.

Cardinal marks indicate that the deepest water...

A type of multihulled vessel featuring two parallel hulls of equal size, connected by a deck or framework, offering stability, speed, and...

A vessel whose ability to deviate from its current course is significantly restricted due to the depth of water relative to its draught.

A...

A navigational situation where two vessels maintain the same relative bearing to each other while the distance between them diminishes, often...

The International Maritime Signal Flag Charlie.

Meaning

Affirmative.
If appended with a Numeral Pennant, a Magnetic Bearing.

Chafing is damage or wear caused by friction between two surfaces, such as ropes rubbing against a boat's railing or sails rubbing against a...

A strong metal plate, usually stainless steel, bolted to a boat’s hull or deck to which the shrouds or stays of the rigging are...

A supplier or dealer specialising in providing equipment, provisions, and supplies for ships and their crews.

A chandler refers to a...

A navigable waterway, often a natural or dredged passage, that allows vessels to travel between larger bodies of water or through shallow...

Pronounced: CHAR-lee

The term for the letter C in the NATO Phonetic Alphabet.

A detailed map used in marine navigation, showing water depths, hazards, and other critical information for safe passage.

A marine chart...

An electronic navigation device used on boats to display electronic navigation charts and track the vessel's position in real-time using GPS...

A flat, dedicated surface aboard a vessel used for spreading out nautical charts and plotting courses during navigation.

A chart table is an...

The second-in-command on a vessel, responsible for overseeing the ship's day-to-day operations, cargo handling, and the safety of the crew and...

The sharp angle or edge formed where the hull's sides meet its bottom, commonly found in hard-chined boats. 

A chine is a critical structural...

Chock-a-block is a nautical term describing when two blocks (pulleys) are pulled so close together that they cannot be tightened further. It...

A highly accurate timekeeping instrument, specifically designed for determining longitude at sea.

A chronometer is a precision timepiece used...

⚓ 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...

Clear water is transparent and free from sediment, debris, or other particles that may obstruct visibility. This is important for snorkelling,...

Clear weather refers to atmospheric conditions free of significant cloud cover, precipitation, fog, or other weather disturbances. The sky is...

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...

A fitting on a boat or dock used to secure lines or ropes. Cleats typically have two horns or arms extending from a base, allowing lines to be...

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...

Used primarily in maritime and aviation contexts to describe the shortest distance that will be achieved between two moving objects, such as...

A clove hitch is a versatile, easy-to-tie knot commonly used to secure a rope to a post or pole temporarily. One of its most common uses is...