Click a letter below to find a specific nautical term
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ABAFT: Toward the rear (stern) of the boat. Aft
ABEAM: At right angle or off to the side of the keel of the boat; at right angle to the middle of the ship.
ABOARD: On or within the boat.
ABOVE DECK: On the deck (not over it: see ALOFT).
AFT: Toward the stern of the boat.
AGROUND: Touching or fast to the bottom of any body of water; on or onto the shore.
AHEAD: In a forward direction.
AIDS TO NAVIGATION (AtoN): Artificial objects to supplement natural landmarks to indicate safe and unsafe waters.
ALOFT: Above or on top of the deck of the boat.
AMIDSHIP(S): In or toward the part of a boat or ship midway between the bow and the stern; toward the middle of the ship or boat.
ANCHOR: A heavy metal device, fastened to a chain or line, to hold a vessel in position, partly because of its weight, but mainly because the designed shape digs into the bottom.
ANCHORAGE: A place suitable for anchoring in relation to the wind, seas and bottom.
ASTERN: In back of the boat, opposite of ahead.
ATHWARTSHIPS: At right angles to the centerline of the boat; across the ship or boatfrom side to side. Rowboat seats are generally athwartships.
BATTEN DOWN: Secure hatches and loose objects both within the hull and on deck.
BEACON: A lighted or unlighted fixed aid to navigation attached directly to the earth’ssurface. (Lights and daybeacons; both constitute “beacons.”)
BEAM: The greatest width of the boat.
BEARING: The direction of an object expressed either as a true bearing as shown on thechart, or as a bearing relative to the heading of the boat.
BELOW: Beneath the deck.
BIGHT: The part of the rope or line, between the end and the standing part, on which a knot is ormed; a slack part or loop in a rope; shallow bay or bend in a coast forming an open bay.
BILGE: The interior of the hull below the floorboards.
BITTER END: The last part of a rope or chain; the inboard end of the anchor rope.
BLOCK: A wooden or metal case enclosing one or more pulleys and having a hook, eye, or strap by which it may be attached.
BOAT: A fairly indefinite term. A waterborne vehicle smaller than a ship; 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.
BOATTALK.COM: The Internet clearing house of personal opinions of boats submitted by boat owners.
BOOM: Poles used to support the sails.
BOW: The forward part of a boat.
BOW LINE: A docking line leading from the bow.
BOW SPRING LINE: A bow pivot line used in docking (and undocking), or to prevent the boat from moving forward or astern while made fast to a pier.
BOWLINE KNOT: A knot used to form a temporary loop in the end of a line.
BOWSPRIT: A spar extending forward from the bow.
BRIDGE: The location from which a vessel is steered and its speed controlled.
BROACH: Sudden, unplanned, and uncontrolled turning of a vessel so that the hull is broadside to the seas or to the wind.
BULKHEAD: A vertical partition separating compartments.
BUOY: An anchored float used for marking a position on the water or a hazardor a shoal and for mooring.
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.
CENTERBOARD: Used to keep the boat from moving sideways under certain wind conditions. It also increases the boat’s stability and aids in steering it.
CHAFING GEAR: Tubing or cloth wrapping used to protect a line from chafing on a rough surface.
CHANNEL: 1.That part of a body of water deep enough for navigation through an area otherwise not suitable. It is usually marked by a single or double line of buoys and sometimes by range markers. 2. The deepest part of a stream, bay, or strait, through which the main current flows. 3. A name given to a large strait, for example, the English Channel.
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. UsuallyU-shaped to reduce chafe.
CLEAT: A fitting, usually with two horn-shaped ends, to which lines are made fast. The classic cleat is almost anvil-shaped.
CLOVE HITCH: A knot for temporarily fastening a line to a spar or piling.
COAMING: A vertical raised frame or 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.
COMPASS: Navigation instrument, either magnetic (showing magnetic north) or gyro (showing true north).
COMPASS CARD: Part of a compass; the circular card graduated in degrees. It is attached to the compass needles and conforms with the magnet meridian-referenced direction system inscribed with direction. The vessel turns not the card.
COMPASS ROSE: The resulting figure when the complete 360° directional system is developed as a circle with each degree graduated upon it. True North is indicated as 000° and is also called true rose. This is printed on nautical charts for determining direction.
CURRENT: The horizontal movement of water.
CUTTER: Similar to a sloop except sails are arranged so that many combinations of areas may be obtained.
DAYBEACON: A fixed navigation aid structure used in shallow waters upon which is placed one or more daymarks.
DAYMARK: A signboard attached to a daybeacon to convey navigational information presenting one of several standard shapes (square, triangle, rectangle) and colors (red, green, orange, yellow, or black). Daymarks usually have reflective material indicating the shape, but may also be lighted.
DEAD AHEAD: Directly ahead.
DEAD ASTERN: Directly aft or behind.
DEAD RECKONING: A plot of courses steered and distances traveled through the water.
DECK : A permanent covering over a compartment, hull or any part of a ship serving as a floor.
DISPLACEMENT: The weight of water displaced by a floating vessel.
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.
DRAFT: The depth of water a boat draws.
EASE: To slacken or relieve tension on a line.
EBB TIDE: A receding tide; a period or state of decline.
EVEN KEEL: When a boat is floating on its designed waterline, it is said to be floating on an even keel.
EYE OF THE WIND: The direction from which the wind is blowing.
EYE SPLICE: A permanent loop spliced in the end of a line.
FAST: Said of an object that is secured to another.
FATHOM : A unit of length equal to 6 feet used in measuring water depth.
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.
FLAME ARRESTER : A safety device, such as a metal mesh protector, to prevent an exhaust backfire from causing an explosion; operates by absorbing heat.
FLARE : The outward curve of a vessel’s sides near the bow; a distress signal.
FLOTSAM: Wreckage or cargo that remains afloat after a ship has sunk. Floating refuse or debris.
FLYING BRIDGE : An added set of controls above the level of the normal control station for better visibility. Usually open, but may have a collapsible top for shade.
FOLLOWING SEA : An overtaking sea that comes from astern.
FORE AND AFT : In a line parallel to the keel.
FORWARD : Toward the bow of the boat.
FOULED : Any piece of equipment that is jammed or entangled, or dirtied.
FOUNDER : When a vessel fills with water and sinks.
FREEBOARD : The minimum vertical distance from the surface of the water to the gunwale.
GAFF : A spar to support the head of a gaff sail.
GAFF RIG : Four-sided mainsail defined by two booms, one located on the bottom, perpendicular to the mast, and another, located on top, at an angle from the mast.
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 VESSEL: A term, from the Navigational Rules, used to describe the vessel which must yield in meeting,crossing, or overtaking situations.
GRAB RAILS: Hand-held fittings mounted on cabin tops and side for personal safety when moving around the boat.
GROUND TACKLE: Anchor, anchor rode (line or chain), and all the shackles and other gear used for attachment.
GUNWALE: The upper edge of a boat’s sides.
HALYARD: Pulls up the sail.
HARBOR: A safe anchorage, protected from most storms; may be natural or manmade, with breakwaters and jetties; a place for docking and loading.
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.
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: To bring a vessel up in a position where it will maintain little or no headway, usually with the bow into the wind or nearly so.
HEEL: To tip to one side.
HELM: The wheel or tiller controlling the rudder.
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.
HYPOLIMNION: The layer of water in a thermally stratified lake that lies below the thermocline, is noncirculating, and remains perpetually cold.
HYPOTHERMIA: A life:threatening condition in which the body’s temperature are subnormal and the entire body cools.