Glossary of Terms
ABAFT - Toward the rear (stern) of the boat. Behind
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 - Toward the stern of the boat
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
AIR DRAUGHT (OR DRAFT) - The overall height of a vessel measured from the water line to the highest fixed part of the superstructure.
ALEE - Away from the direction of the wind. Opposite of windward
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
ANTI-CAVITATION PLATE - On a narrowboat, a plate fitted flush to the uxter plate to cover the weedhatch opening
ASTERN - In back of the boat, opposite of ahead
ATHWARTSHIPS - At right angles to the centerline of the boat; rowboat seats are generally athwart ships
AWEIGH - The position of anchor as it is raised clear of the bottom
BACKSTAY - Part of the standing rigging that supports the mast; it reaches from the stern of the vessel to the mast head
BAGGYWRINKLE - A soft covering for stays and other standing rigging that prevents sail chafing
BATTEN - A stiff strip used to support the roach of a sail
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
BED CUPBOARD - Distinctive cupboard in boatman's cabin fitted on port side between table cupboard and engine room bulkhead.
BELOW - Beneath the deck
BERMUDAN RIG - A triangular mainsail, without any upper spar, which is hoisted up the mast by a single halyard attached to the head of the sail
BERTH - A bed or sleeping accommodation on a boat or ship
BIGHT - The part of the rope or line, between the end and the standing part, on which a knot is formed
BILGE - The interior of the hull below the floor boards
BILGE KEEL - A keel on fastened to the hull off the centre line, often close to the turn of the bilge. They allow a vessel stand upright on two bilge keels, on a drying mooring
BITTER END - The last part of a rope or chain. The inboard end of the anchor rode
BITTS - A post or pair mounted on the ship's bow, for fastening ropes or cables
BLACKING - Term for protective coats of, often bitumen based, paint applied to steel hulls to discourage rusting.
BLOCK - A pulley or set of pulleys
BOAT - A fairly indefinite term. A waterborne vehicle smaller than a ship. One definition is a small craft carried aboard 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
BOBSTAY - A stay which holds the bowsprit downwards, counteracting the effect of the forestay
BOOM - A spar attached to the foot of a fore-and-aft sail
BOOM VANG - A sail control that lets one apply downward tension on a boom, countering the upward tension provided by the sail
BULWARK - The extension of the vessel's hull wall above the level of the weather deck
BUMPKIN - A spar, similar to a bowsprit, but which projects from the stern
BOOT TOP - A painted line that indicates the designed waterline
BOTTLESCREW - A device for adjusting tension in stays, shrouds
BOW - The forward part of a boat
BOW LINE - A docking line leading from the bow
BOWLINE - A knot used to form a temporary loop in the end of a line
BOWSPRIT - A spar projecting forward of the bow
BOW THRUSTER - A small propeller or water-jet at the bow, used to turn a vessel at slow speed. Often mounted in a tunnel running through the bow
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
BRIGHTWORK - Varnished woodwork and/or polished metal
BULKHEAD - A vertical partition separating compartments
BULWARK - The extension of the vessel's hull wall above the level of the weather deck
BUMPKIN - A spar, similar to a bowsprit, but which projects from the stern
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 has been superseded by the term "give-way"
CABIN - A compartment for passengers or crew
CANT - On a narrowboat, a raised outer section of a deck normally to the fore and counter decks
CAPSIZE - To turn over
CARVEL - A constructing wooden hulls by fixing planks to a frame so that the planks butt up against each other to form a smooth hull, where the plank seams cannot easily be seen
CAST OFF - To let go
CATAMARAN - A twin-hulled boat, with hulls side by side
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
CLENCH - A method of fastening in wooden boats using copper boat nails and a rove (similar to a washer). The nail is then burred or riveted over to complete the fastening
CLEW - On a triangular sail, the bottom aft corner, to which the sheets bent on a loose-footed sail
CLINKER - A method of constructing hulls that involves overlapping planks
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
COMPANIONWAY - A stairway from one deck to another
COUNTER - The part of the stern above the waterline that extends beyond the rudder stock. On a narrowboat the counter stern is trimmed to float at the waterline
COUNTER PLATE - On a narrowboat, the stern section of the hull side plating above the waterline that wraps around the stern and corresponds to the counter swim
COURSE - The direction in which a boat is steered
CRANCE - A fitting, mounted at the end of a bowsprit to which forestay and bobstay attach
CRATCH - On a narrowboat, a canvas covering over the forward well deck
CRATCH BOARD - A triangular board or frame supporting the forward end of the cratch covers
CUDDY - A small shelter cabin in a boat
CURRENT - The horizontal movement of water
DEAD AHEAD - Directly ahead
DEAD ASTERN - Directly aft
DECK - A permanent covering over a compartment, hull or any part thereof
DECKHEAD - The under-side of the deck above sometimes covered by the head lining
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
DOCK - A protected water area in which vessels are moored.The term is often used to denote a pier or a wharf
DOLLY - On a narrowboat, a round bollard used for mooring
DOLPHIN - A group of piles driven close together and bound with wire cables into a single structure
DRAFT - The depth of water a boat draws
EBB - A receding current
FAIR - A smooth curve, usually referring to a line of the hull which has no deviations
FAIRLEAD - A ring, hook or other device to keep a line or chain running in the correct direction to prevent it fouling or chafing
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 - The outward curve of a vessel's sides near the bow. A distress signal
FLOOD - A incoming current
FLOORBOARDS - The surface of the cockpit on which the crew stand
FLUKE - The palm of an anchor
FOLLOWING SEA - An overtaking sea that comes from astern
FOOT - The lower edge of a sail
FOOT or FOOTING - On a narrowboat, the lower section of the hull side
FORESTAY - Part of the standing rigging that reaches from the bow of the vessel to the mast heads
FORE-AND-AFT - In a line parallel to the keel
FOREFOOT - The lower part of the stem of a vessel
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
FRAME - A transverse structural member which gives the hull strength and shape. Freeboard The height of a vessel's hull above the waterline
FREEBOARD - The minimum vertical distance from the surface of the water to the gunwale
FUTTOCK - One of several sawn pieces that make up a frame
GOOSENECK - The fitting that attaches the boom to the mast
GALLEY - The kitchen area of a boat
GAMMON IRON - The fitting which clamps the bowsprit to the stem
GANGWAY - The area of a ship's side where people board and disembark
GARBOARD - The plank closest to the keel
GEAR - A general term for ropes, blocks, tackle and other equipment
GENNAKER - A large, lightweight sail used for sailing a fore-and-aft rig down or across the wind, intermediate between a genoa and a spinnaker
GENOA - A large jib, strongly overlapping the mainmast
GIVE-WAY VESSEL - A term used to describe the vessel which must yield in meeting, crossing, or overtaking situations
GOOSENECK - The fitting that attaches the boom to the mast
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 - The upper edge of a boat's sides
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
HAWSEHOLE - The hole in the vessel's deck through which the anchor chain passes
HAWSEPIPE - The pipe in a vessel's bow through which the anchor chain passes
HEAD - A marine toilet. Also the upper corner of a triangular sail
HEADBOARD - A board used to stiffen the head of a sail; the headboard reinforces the holes in the sail where the main halyard is fastened
HEADING - The direction in which a vessel's bow points at any given time
HEADWAY - The forward motion of a boat. Opposite of sternway
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
JACKSTAYS - Usually steel wire attached to the decks that provide a secure point for crew to clip their safety lines
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
JIB - A triangular staysail set forward of the mast
KEDGE - A relatively light anchor known used as a secondary anchor
KEEL - The centerline of a boat running fore and aft; the backbone of a vessel
KNOT - A measure of speed equal to one nautical mile (6076 feet) per hour
KELSON - The timber immediately above the keel of a wooden ship
KING PLANK - The centreline plank of a laid deck
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
LAZARETTE - A storage space in a boat's stern area
LAZYJACKS - A network of cordage rigged that forms a cradle to a sail onto the boom when it is lowered
LEE - The side sheltered from the wind
LEECH - The aft edge of a fore-and-aft sail; the leeward edge of a spinnaker
LEEWARD - The direction away from the wind. Opposite of windward
LEEWAY - The sideways movement of the boat caused by either wind or current
LINE - Rope and cordage used aboard a vessel
LOA - Length overall; the length of a vessel from the forward edge of the stem to the aft edge of the stern post
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
LUFF - The forward edge of a sail
MARLINSPIKE - A tool for opening the strands of a rope while splicing
MAST STEP - The structure members that support the heel of the mast or compression post where the mast is stepped onto a deck or coachroof
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
MOUSE - Secure a shackle or other fitting with wire or cord to prevent it coming undone
NAUTICAL MILE - One minute of latitude; approximately 6076 feet - about 1/8 longer than the statute mile of 5280 feet
NAVIGATION - The art and science of conducting a boat safely from one point to another
NAVIGATION RULES - The regulations governing the movement of vessels in relation to each other, generally called steering and sailing rules
OUTBOARD - Toward or beyond the boat's sides. A detachable engine mounted on a boat's stern
OVERBOARD - Over the side or out of the boat
OVERPLATE - On a steel vessel, plating fitted on top of the hull plate
PARREL - A movable loop or collar, used to fasten a yard or gaff to its mast
PAYING - The compound used to fill a seam, often between planks forming the hull....
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 (see PILING) or a float
PILING - Support, protection for wharves, piers etc.; constructed of piles (see PILE)
PILOTING - Navigation by use of visible references, the depth of the water, etc
PINTLE - The pin or bolt on which a rudder pivots. The pintle rests in the gudgeon.
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.
PORT - The left side of a boat looking forward. A harbor.
PRIVELEGED VESSEL - A vessel which, according to the applicable Navigation Rule, has right-of-way (this term has been superseded by the term "stand-on").
QUARTER - The sides of a boat aft of amidships.
QUARTERING SEA - Sea coming on a boat's quarter.
RABBET - A groove cut in wood to form part of a joint, also know as a rebate.
RIB - Rigid inflatable boat; a fast craft with a rigid, planing hull usually made of GRP or aluminium with inflatable an inflatable collar.
RODE - The anchor line and/or chain.
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.
RUBBING STRAKE - A moulding fitted to the outside of the hull, usually at deck level, to protect the topsides.
RUDDER - A vertical plate or board for steering a boat.
RUDDER NIB - On narrowboats, the extension to the rudder above the waterline.
RUDDER STOCK - The bar, tube or post connecting the rudder vane to the steering mechanism.
RUDDER STOCK TUBE - A tube in the hull through which the rudderstock passes.
RUN - To allow a line to feed freely.
RUNNING LIGHTS - Lights required to be shown on boats underway between sundown and sunup.
RUNNING RIGGING - Rigging used to hoist and set sails.
SACRIFICIAL CHINE - On a narrowboat, an extension of the bottom plate to provide protection and a wear edge for the chine.
SAMPSON POST - A strong post often used as a mooring point.
SAPONIFICATION - Production of an alkaline metal soap that can damage some paint coatings, often as a result of electro chemical activity.
SATELLITE NAVIGATION - A form of position finding using radio transmissions from satellites with sophisticated on-board automatic equipment.
SCANTLING - Dimensions of a vessel's structural members
SCOPE - Technically, the ratio of length of anchor rode in use to the vertical distance from the bow of the vessel to the bottom of the water. Usually six to seven to one for calm weather and more scope in storm conditions.
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.
SEAMANSHIP - All the arts and skills of boat handling, ranging from maintenence and repairs to piloting, sail handling, marlinespike work, and rigging.
SEA ROOM - A safe distance from the shore or other hazards.
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.
SHEER - The concave curve of the deck line from the bow to the stern.
SHIP - A larger vessel usually thought of as being used for ocean travel. A vessel able to carry a "boat" on board.
SHROUDS - Standing rigging from a mast to the sides of a sailing vessel.
SKEG - A downward or sternward projection from the keel in front of the rudder. In some craft the skeg has a bearing that supports the rudder.
SKIN TANK - In narrowboats, a steel tank welded to the interior face of the hull. The skin tank forms part of the engine cooling system; coolant passes through the tank and is cooled by contact with exterior hull plating.
SLACK - Not fastened; loose. Also, to loosen.
SOLE - Cabin or saloon floor. Timber extensions on the bottom of the rudder. Also the molded fiberglass deck of a cockpit.
SOUNDING - A measurement of the depth of water.
SPAR - A pole used to support rigging and sails.
SPREADER - A small fixed spar attached to the mast on a sailing boat that deflects the shrouds to provide better support.
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.
SPURLING PIPE - A pipe that feeds the anchor chain into the chain locker from the deck above.
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.
SQUAT - The effect where the stern of the vessel sinks lower into the water when forward power is engaged.
STACHION - The upright supports along the upper deck that carry the guard rails or wires.
STANDING PART - That part of a line which is made fast.The main part of a line as distinguished from the bight and the end.
STANDING RIGGING - The permanent fixed rigging such the stays and shrouds.
STAND-ON VESSEL - That vessel which has right-of-way during a meeting, crossing, or overtaking situation.
STARBOARD - The right side of a boat when looking forward.
STEERING FLAT - The compartment containing the steering gear.
STEM - The forward most part of the bow.
STERN - The after part of the boat.
STERN GEAR - The propulsion equipment aft of the gear box, including shafts, shaft couples, glands, shaft tubes, struts and propellers.
STERN LINE - A docking line leading from the stern.
STERN TUBE - The tube through the hull through which the propeller shaft passes.
STOW - To put an item in its proper place.STRINGER - Internal structural member that runs fore and aft.
SUPERSTRUCTURE - The structures on a vessel that project above her main deck, not including masts and rigging.
SWAN NECK - On a narrow boat, the S-shaped steel bar that connects the rudder stock to the tiller.
SWIM - On a narrowboat, the underwater section of the hull side that reduces in beam to allow water to flow to the propeller.
SWAMP - To fill with water, but not settle to the bottom.
TABERNACLE - A bracket which allow a mast to pivot so that it can be raised or lowered.
TACK - The forward bottom corner of a sail.
THWARTSHIPS - At right angles to the centerline of the 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.
TIMBER - A stem-bent frame.
TINGLE - A temporary patch on the hull, often a made as an emergency repair. It has been known for tingles to remain in duty for many years.
TOE RAIL - A low strip running around the edge of the deck that helps the crew keep their footing.
TOP STRAKE - On a narrowboat, the upper part of the hull side.
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.
TRIM TABS - Horizontal plates usually attached to the transom of a motor boat that allow the pitch of the vessel be adjusted in response to the squat effect.
TUMBLEHOME - A description of hull or cabin form where the widest part reduces higher up when viewed in a transverse section.
TURNBUCKLE - A device for adjusting tension in stays, shrouds.
UNDERWAY - Vessel in motion, i.e., when not moored, at anchor, or aground.
UXTER PLATE - On a narrowboat, the plate that forms the bottom part of the counter and lies parallel to the bottom plate. It is also known as the counter bottom plate.
V BOTTOM - A hull with the bottom section in the shape of a "V".
WAKE - Moving waves, track or path that a boat leaves behind it, when moving across the waters.
WATERLINE - A line painted on a hull which shows the point to which a boat sinks when it is properly trimmed (see BOOT TOP).
WAY - Movement of a vessel through the water such as headway, sternway or leeway.
WEEDHATCH - An opening in the uxter plate of a narrowboat directly above a propeller, allowing a fouled propeller to be cleared while the boat is afloat.
WINDWARD - Toward the direction from which the wind is coming.
YACHT - A pleasure vessel, a pleasure boat; in American usage the idea of size and luxury is conveyed, either sail or power.
YAW - To swing or steer off course, as when running with a quartering sea.
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