Glossary
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TermDefinition
- General Nautical Terminology Abaft
A position or direction towards the rear (stern) of a vessel relative to a specific point of reference on the boat.
In maritime terminology,...
More Details - General Nautical Terminology Abate
To reduce in intensity, force, or degree, especially in relation to wind, waves, or other marine conditions.
Abate refers to the lessening or...
More Details - General Nautical Terminology, Parts of a Boat Abeam
The position or direction at right angles to the centreline or keel of a vessel, typically on either side of the boat.
Abeam describes...
More Details - General Nautical Terminology, Nautical Saying Above board
Something done openly, honestly, and straightforwardly without deceit or dishonesty. It originates from pirates hiding crew members below deck...
More Details - General Nautical Terminology Above deck
The area of a boat or ship located on the main deck or any higher deck levels. This area is typically exposed to the elements and is where...
More Details - General Nautical Terminology Accidental Gybe
An unintentional and often abrupt change in a sailing vessel's course that causes the boom to swing violently across the boat, typically due to a...
More Details - General Nautical Terminology Adrift
A vessel that is floating without being anchored, moored, or under control, often at the mercy of wind and currents.
Adrift describes a...
More Details - General Nautical Terminology Afloat
The state of being buoyant and on the water's surface, not submerged or sinking.
Afloat is a term commonly used in the maritime world to...
More Details - General Nautical Terminology Aft
The rear or stern section of a vessel, towards the back of the boat or ship.
Aft is a directional term used to describe the position or...
More Details - General Nautical Terminology After Deck
The portion of a vessel's deck located towards the stern, or rear, of the ship.
The after deck, sometimes referred to as the aft deck, is a...
More Details - General Nautical Terminology Aground
The situation when a vessel is stuck on the seabed or shore, unable to move freely in the water.
When a vessel is aground, the hull has come...
More Details - General Nautical Terminology Ahead
The direction in front of a vessel, typically along its forward course or heading.
In maritime terminology, ahead is commonly used to describe...
More Details - General Nautical Terminology Ahoy!
A nautical greeting or hail used to attract attention, signal presence, or establish communication between vessels or individuals at...
More Details - General Nautical Terminology Air Cushioned Vessel
A type of watercraft that uses a cushion of pressurised air beneath its hull to reduce friction and enable movement over water, land, or other...
More Details - General Nautical Terminology AIS
A maritime communication system that automatically transmits and receives vessel information such as position, speed, and course to enhance...
More Details - General Nautical Terminology Alee
The side of a vessel that is sheltered from the wind, also known as the leeward side.
Alee is a nautical term used to describe the side of a...
More Details - General Nautical Terminology Aloft
A position above the deck, typically in the rigging or on the masts of a ship.
Aloft is used to describe any position above a vessel's deck,...
More Details - General Nautical Terminology Alongside
The position or location next to a vessel, dock, or quay where a ship can be moored or secured.
The term alongside is a fundamental concept...
More Details - General Nautical Terminology, Nautical Saying Aloof
Aloof originally had a different meaning than its modern-day use to describe someone emotionally distant. In maritime language, Aloof comes from...
More Details - General Nautical Terminology, Signals & Communication AM
A method of transmitting information by varying the strength (amplitude) of a carrier wave in proportion to the signal being sent.
Amplitude...
More Details - General Nautical Terminology Amidships
The central part of a vessel, both longitudinally and laterally, located between the bow and stern.
Amidships is a crucial term in nautical...
More Details - General Nautical Terminology, Signals & Communication Ampitude Modulation (AM)
A method of transmitting information by varying the strength (amplitude) of a carrier wave in proportion to the signal being sent.
Amplitude...
More Details - General Nautical Terminology Anchor
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...
More Details - General Nautical Terminology Anchorage
A designated area where a vessel can be securely anchored, typically marked on nautical charts and chosen for its safe holding ground and...
More Details - General Nautical Terminology Anchor Aweigh
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...
More Details - General Nautical Terminology Anchor Ball
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...
More Details - General Nautical Terminology Anchor Buoy
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...
More Details - General Nautical Terminology Anchor Cable
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...
More Details - General Nautical Terminology Anchor Light
A white light displayed by a vessel at anchor to indicate its position to other vessels during the night or in poor visibility conditions.
An...
More Details - General Nautical Terminology Anchor Locker
A dedicated storage compartment, typically located in the bow of a vessel, used to store the anchor and its associated gear, such as the rode and...
More Details - General Nautical Terminology Anchor Roller
A fitting mounted on a boat's bow designed to guide, support, and secure the anchor and its rode during deployment and retrieval.
An anchor...
More Details - General Nautical Terminology, Safety Angle of Vanishing Stability (AVS)
The maximum angle of heel at which a vessel can recover to an upright position without capsizing.
The Angle of Vanishing Stability (AVS) is a...
More Details - General Nautical Terminology AntifoulPaint applied to hull below waterline to discourage dirt and wildlife attaching and slowing your progress. Has environmental implications
- General Nautical Terminology, Navigation APEM More Details
- General Nautical Terminology Apparent WindThe wind we feel. If the true wind is hitting the boat on the beam or in front of the beam the apparent wind will be situated between the boat... More Details
- General Nautical Terminology, Navigation Appraise, Plan, Execute, Monitor (APEM) More Details
- General Nautical Terminology AshoreOn the land; or aground
- General Nautical Terminology, Parts of a Boat Astern
The area or direction behind a vessel, towards the stern.
Astern is a nautical term used to describe both a direction and a movement in...
More Details - General Nautical Terminology Asymetric Spinnaker
A large, lightweight sail with an off-centre shape, designed for sailing off the wind, typically used to improve downwind performance.
An...
More Details - General Nautical Terminology Automatic Identification System (AIS)
A maritime communication system that automatically transmits and receives vessel information such as position, speed, and course to enhance...
More Details - General Nautical Terminology Autonomous Underwater Vehicle (AUV)
An Autonomous Underwater Vehicle (AUV) is a self-propelled, unmanned underwater vehicle capable of operating independently without direct human...
More Details - General Nautical Terminology AutopilotEquipment that allows the boat steer a course automatically using either compass bearing or a course relative to wind direction
- General Nautical Terminology AUV
An Autonomous Underwater Vehicle (AUV) is a self-propelled, unmanned underwater vehicle capable of operating independently without direct human...
More Details - General Nautical Terminology AuxiliaryA term for a saying a boat that has auxiliary power, i.e. an engine
- General Nautical Terminology, Safety AVS
The maximum angle of heel at which a vessel can recover to an upright position without capsizing.
The Angle of Vanishing Stability (AVS) is a...
More Details - General Nautical Terminology AwashLevel with the surface of the water which just washes over an object
- General Nautical Terminology Baby StayAn inner forestay
- General Nautical Terminology Back
Back (backing) describes the wind’s change in direction when it shifts counterclockwise (anti-clockwise). For example, if the wind shifts from...
More Details - General Nautical Terminology Back
To back a sail means to adjust it so that the wind blows on the opposite side from normal, causing the sail to push the boat in the opposite...
More Details - General Nautical Terminology Back StayThe backstay runs from the top of the mast to the stern of the vessel. The backstay supports the mast and in some cases can be adjusted to change... More Details
- General Nautical Terminology BailTo remove water from the bilges or cockpit
- General Nautical Terminology BailerA utensil used to bail water out of a boat
- General Nautical Terminology, Weather (Meteorology) Bailey
Sea area of the Met Office Shipping Forecast. Lies off northern Scotland near Bill Bailey’s Bank and the Orkney Islands.
Named for Bill Bailey’s...
More Details - General Nautical Terminology Ball
A spherical shape or object used as a day signal to indicate a vessel's status or condition, such as being anchored or aground.
In maritime...
More Details - General Nautical Terminology BallastAdditional weight placed low in the hull to improve stability
- General Nautical Terminology BarA shallow area (shoal) close by a river mouth or harbour entrance or A measure of barometric pressure usually noted as 1000 millibars
- General Nautical Terminology Barber Hauler
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...
More Details - General Nautical Terminology Bare PolesNo sails are set and boat is driven by the force of the wind on the spars and rigging
- General Nautical Terminology Bathing Platform
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...
More Details - General Nautical Terminology Batten
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...
More Details - General Nautical Terminology Batten Pocket
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...
More Details - General Nautical Terminology BeachTo run a vessel ashore deliberately
- General Nautical Terminology Beacon
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...
More Details - General Nautical Terminology, Parts of a Boat Beam
The widest part of a vessel, measured at its broadest point across the hull.The term beam is a fundamental concept in nautical terminology,...
More Details - General Nautical Terminology Beam Reach
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...
More Details - General Nautical Terminology Bear AwayTo alter course away from the wind
- General Nautical Terminology, Navigation Bearing
The direction or angle between a reference point, typically true north, and an object or destination, usually expressed in degrees.
A bearing...
More Details - General Nautical Terminology, Navigation Bearing to Waypoint (BTW)
The direction from a vessel's current position to a predetermined navigational point or waypoint.
In marine navigation, Bearing to Waypoint is...
More Details - General Nautical Terminology BeatingSailing towards the wind with the sails hauled in tight
- General Nautical Terminology, Weather (Meteorology) Beaufort Scale
A scale used for estimating and reporting wind speeds based on observed sea conditions.
British Admiral Sir Francis Beaufort developed it in...
More Details - General Nautical Terminology Below Deck
Below deck refers to the interior spaces of a vessel located beneath the main deck or upper deck. These areas typically include crew quarters,...
More Details - General Nautical Terminology Bermudan Rig
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...
More Details - General Nautical Terminology BerthA place where a vessel can be tied up; A sleeping place on a vessel; To give an obstruction wide clearance by keeping well clear
- General Nautical Terminology Bi-colour LightCombined red (port) and green (starboard) light positioned on the bow
- General Nautical Terminology Bight
A loop created in the standing part of a rope.
- General Nautical Terminology Bilge PumpUsed to empty unwanted water from the vessel. Can be automatic, manual and mobile and are usually positioned to collect the water from the lowest... More Details
- General Nautical Terminology BilgesThe compartment at the bottom of the hull of a ship or boat where water collects and must be pumped out of the vessel.
- General Nautical Terminology Bimini
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...
More Details - General Nautical Terminology BinnacleThe stand on which the ship's compass is mounted, usually in front of the wheel. May also carry navigation instruments.
- General Nautical Terminology, Weather (Meteorology) Biscay
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...
More Details - General Nautical Terminology Block
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...
More Details - General Nautical Terminology Boat HookA pole with a hook on the end, used to reach into the water to catch buoys or other floating objects.
- General Nautical Terminology Boat WindJust like running down the road or cycling downhill you will feel the wind on your face; boat wind is just the same. As the boat moves through the... More Details
- General Nautical Terminology BollardStrong fitting, firmly bolted to the deck, to which mooring lines are made fast. Large bollards are on quays, piers and pontoons
- General Nautical Terminology Boom
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...
More Details - General Nautical Terminology Boom OutOn a run to thrust the Genoa out to windward so that it fills with wind
- General Nautical Terminology, Weather (Meteorology) Bora
A strong, cold, and dry northeasterly katabatic wind that blows from the land to the sea, particularly along the eastern Adriatic coast.
The...
More Details - Did you know?, General Nautical Terminology Bosun
Short for boatswain, the Bosun is a senior crew member responsible for the vessel's maintenance, repair, and overall operation. The bosun...
More Details - General Nautical Terminology, Parts of a Boat Bow
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...
More Details - General Nautical Terminology Bow Line
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,...
More Details - General Nautical Terminology, Knot Bowline
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...
More Details - General Nautical Terminology Bow Spring
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...
More Details - General Nautical Terminology BowspritA spar projecting from the bow used to attach the tack of some headsails, particularly asymmetric spinnakers
- General Nautical Terminology BreakwaterA structure constructed on a coast as part of a coastal defense system or to protect an anchorage from the effects of weather and longshore drift.
- General Nautical Terminology BroachWhen a sailing vessel loses control of its motion and is forced into a sudden sharp turn, often heeling heavily and in smaller vessels sometimes... More Details
- General Nautical Terminology Broad Reach
More Details
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... - General Nautical Terminology Bruce Anchor
A type of claw-shaped anchor designed to provide strong holding power in a variety of seabed conditions.

The Bruce anchor, also known as...
More Details - General Nautical Terminology, Navigation BTW
The direction from a vessel's current position to a predetermined navigational point or waypoint.
In marine navigation, Bearing to Waypoint is...
More Details - General Nautical Terminology BulkheadAn upright wall within the hull of a ship. Particularly a watertight, load-bearing wall.
- General Nautical Terminology BungSoftwood device for plugging holes in vessel or failed seacocks.

