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Boating Terminology

A-Z of Boating Terms and Definitions

Have you ever been stumped by an old boating term or phrase? Or, perhaps you’d just like to learn more boating lingo. Our comprehensive list of boating terminology will set you on the right course. Simply click on the letter of the alphabet that your search word begins with to fast track your boating definition search. Or, take your time to scroll down the page to review all the boating terms.

ABEAM	At right angles to the keel of the boat, but not on the boat.
ABOARD	On or within the boat.
ABOVE DECK	On the deck (not over it – see ALOFT)
ABREAST	Side by side; by the side of.
ADRIFT	Loose, not on moorings or towline.
AFT	Towards the stern (rear) of the vessel.
AGROUND	Touching or fast to the bottom.
AHEAD	In a forward direction.
AIDS TO NAVIGATION	Artificial objects to supplement natural landmarks indicating safe and unsafe waters.
ALEE	Away from the direction of the wind. Opposite of windward.
ALL STANDING	To have all sails flying when running before the wind.
ALOFT	Above the deck of the boat.
AMIDSHIPS	In or toward the center of the boat.
ANCHORAGE	A place suitable for anchoring in relation to the wind, seas and bottom.
APPARENT WIND	The combination of the true wind and the wind caused by the boat’s own speed
ASTERN	In back of the boat, opposite of ahead.
ASTERN, TO GO ASTERN	Go backwards, put the engine in reverse.
ATHWARTSHIPS	At right angles to the centerline of the boat; rowboat seats are generally athwart ships.
AUTOPILOT	A device – may be electronic or mechanical – used for keeping the boat on course without having to steer it.. It uses a compass, and is attached to the boat’s steering mechanism.
AUXILIARY POWER	An engine that is permanently installed on the boat used for functions other than propulsion (although it occasionally is used to power the boat). Oars are sometimes referred to as the auxiliary power in jest.
AWEIGH	The position of anchor as it is raised clear of the bottom.

BAILER	Bucket for removing water from a boat to prevent it sinking.
BALLAST	A very heavy material, such as lead or iron, placed in the keel of the boat, or in the bilge. It is used to provide stability.
BATTEN DOWN	Secure hatches and loose objects both within the hull and on deck.
BEAM	The greatest width of the boat.
BEARING	The direction of an object expressed either as a true bearing as shown on the chart, or as a bearing relative to the heading of the boat.
BEARING AWAY	Turning away from the wind.
BELOW	Beneath the deck.
BILGE	The interior of the hull below the floor.
BILGE PUMP	A pump to remove bilge water. Electric, manual pumps and buckets can be used for this function.
BIMINI	Weather-resistant fabric stretched over a stainless steel frame, fastened above the cockpit of a sailboat or flybridge of a power yacht which serves as a rain or sun shade.
BITTER END	The last part of a rope or chain.The inboard end of the anchor rode.
BOAT	A very broad term for a waterborne vehicle smaller than a ship.
BOAT HOOK	A short shaft with a fitting at one end shaped to facilitate use in putting a line over a piling, recovering an object dropped overboard, or in pushing or fending off.
BOOM	A pole running at a right angle from the mast.
BOW	The front end of the vessel.
BOW LINE	A docking line leading from the bow.
BOWER	The main anchor of a boat – carried at the bow.
BOWLINE	A knot used to form a temporary loop in the end of a line.
BRIDGE	The location from which a vessel is steered and its speed controlled. “Control Station” is really a more appropriate term for small craft.
BRIDLE	A line or wire secured at both ends in order to distribute a strain between two points.
BULKHEAD	A vertical partition separating compartments.
BUOY	An anchored float used for marking a position on the water or a hazard or a shoal and for mooring.
BURDENED VESSEL	That vessel which, according to the applicable Navigation Rules, must give way to the privileged vessel. The term in many states has been superseded by the term “give-way”.

CABIN	A compartment for passengers or crew.
CAPSIZE	To turn over.
CAST OFF	To let go.
CATAMARAN	A twin-hulled boat, with hulls side by side.
CENTREBOARD	A pivoting board that prevents the boat from sliding sideways.
CHAFING GEAR	Tubing or cloth wrapping used to protect a line from chafing on a rough surface.
CHART	A map for use by navigators.
CHINE	The intersection of the bottom and sides of a flat or v-bottomed boat.
CHOCK	A fitting through which anchor or mooring lines are led. Usually U-shaped to reduce chafe.
CLEAT	A fitting to which lines are made fast. The classic cleat to which lines are belayed is approximately anvil-shaped.
CLOVE HITCH	A knot for temporarily fastening a line to a spar or piling.
COAMING	A vertical piece around the edge of a cockpit, hatch, etc. to prevent water on deck from running below.
COCKPIT	An opening in the deck from which the boat is handled.
COIL	To lay a line down in circular turns.
COURSE	The direction in which a boat is steered.
CUDDY	A small shelter cabin in a boat.
CUNNINGHAM (also called a Downhaul):	Adjusting the tension of a sail’s luff.
CURRENT	The horizontal movement of water.

DAVIT	Device (like a small crane) for lifting a tender on and off a boat.
DEAD AHEAD	Directly ahead.
DEAD ASTERN	Directly aft.
DEAD RECKONING	Navigating.
DEADRISE	The design angle between the keel and horizontal. A vessel with a 0 degree deadrise has a flat bottom where as a a higher degree will indicate a deeper ‘v’ shaped hull.
DECK	A permanent covering over a compartment, hull or any part thereof.
DECKHAND	The person responsible for cleaning the deck and generally maintaining the a vessel.
DINGHY	A small open boat. A dinghy is often used as a tender for a larger craft.
DISPLACEMENT	The weight of water displaced by a floating vessel, thus, a boat’s weight.
DISPLACEMENT HULL	A type of hull that plows through the water, displacing a weight of water equal to its own weight, even when more power is added.
DISTANCE	Where ‘miles’ are referred to as ‘nautical’ miles are meant One (1) nautical mile = 1.852 km
DOCK	A protected water area in which vessels are moored.The term is often used to denote a pier or a wharf.
DRAFT	The depth of water a boat draws.

EBB	A receding current.
ENSIGN	A flag indictating the nationality of a vessel.
EPIRB	Emergency Position Indicating Radio Beacon.

FATHOM	Six feet.
FENDER	A cushion, placed between boats, or between a boat and a pier, to prevent damage.
FIGURE EIGHT KNOT	A knot in the form of a figure eight, placed in the end of a line to prevent the line from passing through a grommet or a block.
FLARE	A distress signal. Also – the outward curve of a vessel’s sides near the bow.
FLOOD/FLOW	A incoming current.
FLYBRIDGE	A driving station above the main level of the boat.
FOLLOWING SEA	An overtaking sea that comes from astern.
FORE-AND-AFT	In a line parallel to the keel.
FOREPEAK	A compartment in the bow of a small boat.
FORWARD	Toward the bow of the boat.
FOULED	Any piece of equipment that is jammed or entangled, or dirtied.
FREEBOARD	The minimum vertical distance from the surface of the water to the gunwale.

GALLEY	The kitchen area of a boat.
GANGWAY	The area of a ship’s side where people board and disembark.
GEAR	A general term for ropes, blocks, tackle and other equipment.
GIVE WAY	Slow, stop, go astern or change course to keep clear of another vessel
GIVE-WAY VESSEL	A term used to describe the vessel which must yield in meeting, crossing, or overtaking situations.
GRAB RAILS	Hand-hold fittings mounted on cabin tops and sides for personal safety when moving around the boat.
GROUND TACKLE	A collective term for the anchor and its associated gear.
GUNWALE/S	The upper edge of a boat’s sides (pronounced gunnels).

HARD CHINE	An abrupt intersection between the hull side and the hull bottom of a boat so constructed.
HATCH	An opening in a boat’s deck fitted with a watertight cover.
HEAD	A marine toilet. Also the upper corner of a triangular sail.
HEAD UP	Sailing closer to the wind.
HEADING	The direction in which a vessel’s bow points at any given time.
HEADWAY	The forward motion of a boat. Opposite of sternway.
HEAVE TO	Steering into the wind and sea making minimum headway
HELM	The wheel or tiller controlling the rudder.
HELMSPERSON	The person who steers the boat.
HITCH	A knot used to secure a rope to another object or to another rope, or to form a loop or a noose in a rope.
HOLD	A compartment below deck in a large vessel, used solely for carrying cargo.
HULL	The main body of a vessel.

INBOARD	More toward the center of a vessel; inside; a motor fitted inside a boat.
IRONS	Boat is pointing into the wind, sail is flapping and probably also going backwards.

JACOBS LADDER	A rope ladder, lowered from the deck, as when pilots or passengers come aboard.
JETTY	A structure, usually masonry, projecting out from the shore; a jetty may protect a harbor entrance.

KEEL	The centerline of a boat running fore and aft; the backbone of a vessel.
KICKER (also called a Vang)	A device used to keep the boom from rising.
KNOT	A measure of speed equal to one nautical mile (1.852km) per hour.
KNOT	A fastening made by interweaving rope to form a stopper, to enclose or bind an object, to form a loop or a noose, to tie a small rope to an object, or to tie the ends of two small ropes together.

LATITUDE	The distance north or south of the equator measured and expressed in degrees.
LAYLINE	The course on which your boat, sailing close – hauled on starboard tack, can just make a windward mark which is to be rounded to port is the starboard – tack lay line for that mark, and the most windward line on which you would approach the mark on port tack is the port – tack lay line.
LAZARETTE	A storage space in a boat’s stern area.
LEAGUE	A unit of length, normally equal to 3 nautical miles
LEE	The side sheltered from the wind.
LEEWARD	The direction away from the wind. Opposite of windward.
LEEWAY	The sideways movement of the boat caused by either wind or current.
LENGTH OVERAL (LOA)	The total length of a boat.
LENGTH WATER LINE (LWL)	The length of the boat touching the water.
LIFE BUOY	Floating safety ring to assist in “person overboard” situations.
LINE	Rope and cordage used aboard a vessel.
LOG	A record of courses or operation. Also, a device to measure speed.
LONGITUDE	The distance in degrees east or west of the meridian at Greenwich, England.
LUBBER’S LINE	A mark or permanent line on a compass indicating the direction forward parallel to the keel when properly installed.
LUFFING	Pointing the boat into the wind – sail flapping.

MAINSHEET	Line that controls the position of the mainsail.
MAKING WAY	Vessel under way and moving through the water, using power or sail
MARK	An object the sailing instructions require a boat to pass on a specified side.
MARLIN BOARD	Like a swim board. A small deck on the aft (rear) of the boat to make accessing the water easier.
MARLINSPIKE	A tool for opening the strands of a rope while splicing.
MAST	A pole usually going straight up from the deck (height can be tuned for different body weights), used to attach sail and boom.
MIDSHIP	Approximately in the location equally distant from the bow and stern.
MOORING	An arrangement for securing a boat to a mooring buoy or a pier.

NAUTICAL MILE	One minute of latitude; approximately 1.852kms
NAVIGATION	The art and science of conducting a boat safely from one point to another.
NAVIGATION LIGHTS	Red, green and white lights required by vessels between sunset and sunrise and in restricted visibility.
NAVIGATION RULES	The regulations governing the movement of vessels in relation to each other.

OBSTRUCTION	Is an object that a boat could not pass without changing course substantially to avoid it. e.g. a mark, a rescue boat, the shore, perceived underwater dangers or shallows.
OUTBOARD	A detachable engine mounted on a boat’s stern.
OUTHAUL	An adjuster that tensions the sail’s foot.
OVERBOARD	Over the side or out of the boat.

PFD	Personal Flotation Device – Lifejacket. They come in categories 1, 2 & 3 depending on usage and are compulsory in Australia.
PIER	A loading platform extending at an angle from the shore.
PILE	A wood, metal or concrete pole driven into the bottom. Craft may be made fast to a pile; it may be used to support a pier.
PILOTING	Navigation by use of visible references, the depth of the water, etc.
PITCH	A vessel’s motion, rotating about the beam axis, so the bow pitches up and down.
PLANING	A boat is said to be planing when it is essentially moving over the top of the water rather than through the water.
PLANING HULL	A type of hull shaped to glide easily across the water at high speed.
PLIMSOL LINE	The mark on the hull of a ship that shows where the waterline is when the boat is at full capacity.
PORT	The left side of a boat looking forward. A harbour.
PORT TACK	Wind across the port side.
PRIVELEGED VESSEL	A vessel which, according to the applicable Navigation Rule, has right-of-way.
PWC	Any recreational vessel that is of a kind that is required to be registered and that: is power driven, has a fully enclosed hull, does not retain water on it if it capsizes or is designed to be operated by a person standing, sitting astride or kneeling on the vessel, but not seated within the vessel.

QUARTER	The sides of a boat aft (behind) of amidships (middle of ship).

REACHING	Sailing with the sail eased.
REEFING	Reducing the amount of sail area.
RIG	The arrangement of a boat’s mast, sails and spars.
ROPE	In general, cordage as it is purchased at the store. When it comes aboard a vessel and is put to use it becomes line.
ROLL	A vessel’s motion rotating from side to side, about the fore-aft axis. “List” is a lasting tilt in the roll direction
RUDDER	An underwater vertical plate or board for steering a boat.
RUN	To allow a line to feed freely.
RUNNING LIGHTS	Lights required to be shown on boats underway between sunset and sunrise.
RUNNING	Sailing before the wind with the sail out.

SAIL TRIM	The position of the sails relative to the wind and desired point of sail.
SAND BAR	An area in shallow water where wave or current action has created a small, long hill of sand. Since they are created by water movement, they can move and may not be shown on a chart.
SATELLITE NAVIGATION (SAT. NAV.)	A form of position finding using radio transmissions from satellites with sophisticated on-board automatic equipment.
SCOPE	The ratio of length of anchor line in use to the vertical distance from the bow of the vessel to the bottom of the water.
SCREW	A boat’s propeller.
SCUPPERS	Drain holes on deck, in the toe rail, or in bulwarks or (with drain pipes) in the deck itself.
SEA COCK	A through hull valve, a shut off on a plumbing or drain pipe between the vessel’s interior and the sea.
SEA ROOM	A safe distance from the shore or other hazards.
SEAMANSHIP	All the arts and skills of boat handling, ranging from maintenence and repairs to piloting, sail handling and rigging.
SEAWORTHY	A boat or a boat’s gear able to meet the usual sea conditions.
SECURE	To make fast.
SET	Direction toward which the current is flowing.
SEXTANT	A navigational instrument used to determine the vertical position of an object such as the sun, moon or stars. Used with celestial navigation.
SHIP	A larger vessel usually thought of as being used for ocean travel. A vessel able to carry a “boat” on board.
SLACK	Not fastened; loose. Also, to loosen.
SOUNDING	A measurement of the depth of water.
SPEED	All speeds are measured in ‘knots’ One knot = 1 nautical mile per hour
SPINNAKER POLE	Sometimes called a spinnaker boom. A pole used to extend the foot of the spinnaker beyond the edge of the boat, and to secure the corner of the sail.
SPINNAKER	A very large lightweight sail used when running or on a broad reach.
SPREADER	Small spars extending toward the sides from one or more places along the mast. The shrouds cross the end of the spreaders, enabling the shrouds to better support the mast.
SPRING LINE	A pivot line used in docking, undocking, or to prevent the boat from moving forward or astern while made fast to a dock.
SQUALL	A sudden, violent wind often accompanied by rain.
SQUARE KNOT	A knot used to join two lines of similar size. Also called a reef knot.
STARBOARD	The right side of a boat when looking forward.
STARBOARD TACK	Wind across the starboard (right) side.
STEM	The forward most part of the bow.
STERN	The back end or rear of a vessel
STERN LINE	A docking line leading from the stern.
STOW	To put an item in its proper place.
STRONG WIND WARNING	A warning for small craft when winds of 25 knots are expected.
SWAMP	To fill with water, but not settle to the bottom.
SWIMBOARD	A platform at the back of the boat to allow easy access to the water.

TACKING	Changing direction by turning into the wind.
TENDER	A small boat used for moving passengers from shore to the main boat or ‘mother boat’.
TIDE	The periodic rise and fall of water level in the oceans.
TILLER	A bar or handle for turning a boat’s rudder or an outboard motor.
TOPSIDES	The sides of a vessel between the waterline and the deck; sometimes referring to onto or above the deck.
TRANSOM	The stern cross-section of a square sterned boat.
TRIM	Fore and aft balance of a boat.
TRUE WIND	The strength and direction of the actual wind blowing. While sailing, the true wind is never felt – it is always a combination of the true wind, and the boat’s speed (called the apparent wind), and it is always a little forward to the true wind.

UNDERWAY	Vessel in motion, i.e., when not moored, at anchor, or aground.

V BERTH	Bunks forming a V at the front of a boat
V BOTTOM	A hull with the bottom section in the shape of a “V”.
V SHEET	A fluorescent orange-red coloured sheet (1.8×1.2m) with a large black “V” printed in the middle. V-Sheets are required to be carried by all vessels operating off shore. They can be spread over the deck of a boat or flown as a flag to indicate that you are in trouble.

WAKE	Moving waves, track or path that a boat leaves behind it, when moving across the waters.
WASH	Same as Wake – Waves made by a vessel making way
WATERLINE	A line painted on a hull which shows the point to which a boat sinks when it is properly trimmed
WAY	Movement of a vessel through the water such as headway, sternway or leeway.
WINDWARD	Toward the direction from which the wind is coming (upwind).

YACHT	A pleasure vessel, a pleasure boat. Can refer to sail or power vessel.

ZINC BLOCK	A sacrificial block of metal, usually zinc, to be eaten away by electrolysis under water, saving your underwater metal parts