Boating Terms


A-Z of Boating Terms and Definitions

Simply click on the letter of the alphabet that your search word begins with, or 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.
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
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