Nautical Dictionary

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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.
AGROUND: Touching or fast to the bottom of any body of water; on or onto the shore.
AHEAD: In a forward direction.
ALOFT: Above or on top of the deck of the boat.
ANCHORAGE: A place suitable for anchoring in relation to the wind, seas and bottom.
ASTERN: In back of the boat, opposite of ahead.


BACK AND FILL: Denotes a mode of tacking when the tide is with the vessel and the wind is against it. Metaphorically, to be irresolute.
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.")
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.
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 waterborne vehicle smaller than a ship; a small craft carried aboard a ship.
BOOM: Poles used to support the sails.
BOWSPRIT: A spar extending forward from the bow.
BRIDGE: The location from which a vessel is steered and its speed controlled.
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.
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.
CLEAT: A fitting, usually with two horn-shaped ends, to which lines are made fast. The classic cleat is almost anvil-shaped.
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.
COMPANION: A wooden covering over the staircase to a cabin.
COMPASS: Navigation instrument, either magnetic (showing magnetic north) or gyro (showing true north).
CURRENT: The horizontal movement of water.
CUTTER: Similar to a sloop except sails are arranged so that many combinations of areas may be obtained.


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.
DOCK: A protected water area in which vessels are moored. The term is often used to denote a pier or a wharf.
DOUSE: To drop a sail quickly.
DRIFT: A vessels leeway.
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.
EPIRB: Emergency Position Indicating Radio Beacon. An emergency device that uses a radio signal to alert satellites or passing airplanes to a vessel's position.
ESCUTCHEON: The part of a vessel's stern where her name is written.
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.


FAGGED: Said of a rope with an untwisted end.
FAST: Said of an object that is secured to another.
FATHOM: A unit of length equal to 6 feet used in measuring water depth.
FEATHER: To turn the blade of an oar horizontally with the top aft as it comes out of the water.
FENDER: A cushion placed between boats, or between a boat and a pier, to prevent damage.
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.
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.
GALLEY: The kitchen area of a boat.
GALLOWS: A frame used to rest the boom when the sail is down.
GANGWAY: The area of a ship's side where people board and disembark.
GEAR: A general term for ropes, blocks, tackle and other equipment.
GUNWALE: The upper edge of a boat's sides.


HAIL: To speak or call to another vessel or to persons in a different part of a ship.
HALYARD: Pulls up the sail and the wooden poles (boom and gaff) that hold the sails in place.
HATCH: An opening in a boat's deck fitted with a watertight cover.
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.
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.


IN IRONS: A sailboat with its bow pointed directly into the wind, preventing the sails from filling properly so that the boat can move.
INBOARD: More toward the center of a vessel; inside; a motor fitted inside the boat.


JACKSTAY: A strong line or wire stay running from bow to stern along the sides of a boat.
JACOBS LADDER: A rope ladder with wooden steps.
JETTISON: To cast overboard or off. Informal. To discard something as unwanted or burdensome.
JIB: A triangular foresail in front of the foremast.
JIB BOOM: Spar forward of bowsprit to which the the tack of the jib is lashed.
JIGGER: Aft sail on the mizzenmast of a yawl or a ketch. After mast (4th mast) on schooner or sailing ship carrying a spanker.
JOLLY BOAT: A small boat, usually hoisted at the stern.
JURY MAST: A temporary mast, rigged at sea, in place of one lost.


KEEL: The centerline of a boat running fore and aft; the backbone of a vessel.
KEEL HAUL: To pass a person backwards and forwards under a ship's keel for certain offenses.
KEELSON: A timber placed over the keel on the floor-timbers, and running parallel with it.
KENTLEDGE: Pig-iron ballast, laid each side of the keelson.
KETCH: A two-masted sailboat with the smaller after mast stepped ahead of the rudderpost.


LABOR: A vessel is said to labor when she rolls or pitches heavily.
LACUSTRINE: Of or relating to lakes; Living or growing in or along the edges of lakes
LARBOARD: The left side of a vessel, looking forward.
LARBOWLINES: The familiar term for the men in the larboard watch.
LARGE: A vessel is said to be going large, when she has the wind free.
LATCHINGS: Loops on the head rope of a bonnet, by which it is laced to the foot of the sail.
LATITUDE: The distance north or south of the equator measured and expressed in degrees.
LAZARETTE: A storage compartment in the stern.
LEEWAY: The sideways movement of the boat caused by either wind or current.
LINE: Rope and cordage used aboard a vessel.
LONGITUDE: The distance in degrees east or west of the meridian at Greenwich, England.


MAINMAST: The tallest mast of the ship; on a schooner, the mast furthest aft.
MAINSAIL: The sail set on the mainmast.-the lowest square sail on the mainmast.
MARLINESPIKE: A tool for weaving and splicing rope.
MATE: An officer under the master.
MONOHULL: A boat with one hull.
MOORING: An arrangement for securing a boat to a mooring buoy or a pier.


NAUTICAL MILE: Any of various units of distance used for sea and air navigation; an international unit equal to 6076.115 feet (1852 meters); 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.
NEAP TIDES: Low tides, coming at the middle of the moon's second and fourth quarters.
NET TONNAGE: A vessel's measurement of cargo carrying capacity.


OAR: A long wooden instrument with a flat blade at one end, used for propelling a variety of different types of vessels.
ORLOP: The lower deck of a ship of the line; or that on which the cables are stowed.
OUTBOARD: Toward or beyond the boat's sides. Also a detachable engine mounted on a boat's stern.
OVERBOARD: Over the side of or out of the boat.


PAINTER: A line attached to the bow of a boat for use in towing or making fast.
PAY OUT: To ease out a line, or let it run in a controlled manner.
PENDANT: The line by which a boat is connected to a mooring buoy; a short rope hanging from a spar having at its free end a spliced thimble or a block.
PIER: A loading/landing platform extending at an angle from the shore.
PILOTING: Navigation by using visible references.
PITCHPOLE: To turn end over end in very rough seas.
POOP: A deck raised over the after part of the spar deck.
PROPELLER: A rotating device, with two or more blades, that acts as a screw in propelling a vessel.


QUARTER: The sides of a boat aft of amidships.
QUARTERDECK: That part of the upper deck abaft the main-mast.
QUARTERING SEA: Sea coming on a boat's quarter.
QUAY: wharf used to discharge cargo.
QUEEN TOPSAIL: small stay sail located between the foremast and mainmast.


RACK: To seize two ropes together, with cross-turns. Also, a fair-leader for running rigging.
RAKE: The inclination of a mast from the perpendicular.
RAMLINE: A line used in mast-making to get a straight middle line on a spar.
REEF: To reduce the sail area.
RIGGING: The general term for all the lines of a vessel.
RODE: The anchor line and/or chain.
RUDDER: A vertical plate or board for steering a boat.
RUNNING LIGHTS: Lights required to be shown on boats underway between sundown and sunup.


SCREW: A boat's propeller. SCUPPER: An opening in the side of a ship at deck level to allow water to run off. An opening for draining off water, as from a floor or the roof of a building.
SEA ANCHOR: Any device used to reduce a boat's drift before the wind.
SHACKLE: A "U" shaped connector with a pin or bolt across the open end.
SHEET: Adjusts a sail's angle to the wind.
SHEET BEND: A knot used to join two ropes. Functionally different from a square knot in that it can be used between lines of different diameters.
SLACK: Not fastened; loose; to loosen.
SQUALL: A sudden, violent wind often accompanied by rain.
SQUARE - RIGGER: Large ships dating back to the 17th century typically with three masts carrying rectangular sails mounted on horizontal beems called yards.
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.
STERN: The after part (back) of the boat.
STOW: To pack or store away; especially, to pack in an orderly, compact manner. SWAMP: To fill with water, but not settle to the bottom.


TAUT: Tight.
TAUNT: High or tall. Commonly applied to a vessel's masts.
TIDE: The periodic rise and fall of water level in the oceans.
TOPMAST: A second spar carried at the top of the fore or main mast, used to fly more sail.
TOPSAIL: The sail above the lowermost sail on a square-rigged ship; also, the sail set above and sometimes on the gaff in a fore-and-aft rigged ship.
TRANSOM: The stern cross-section of a square-sterned boat; any transverse beams secured to the sternpost.
TRIM: Fore and aft balance of a boat.
TRIMARAN: A boat with three hulls.
TUMBLE HOME: Refers to a cabin or hull with a width that becomes narrower as height increases.
TURNBUCKLE: A threaded, adjustable rigging fitting, used for stays, lifelines, and sometimes other rigging.


UNBEDN: To cast off or untie.
UNDERWAY: Vessel in motion - one not moored, at anchor, or aground.


V-BOTTOM: A hull with the bottom section in the shape of a "V."
VARIATION: The angular difference between the magnetic meridian and the geographic meridian at a particular location.
VHF RADIO: A very high frequency electronic communications and direction finding system.


WAKE: Moving waves, track or path that a boat leaves behind when moving across the waters.
WAY: Movement of a vessel through the water, such as headway, sternway, or leeway.
WINCH: A device used to increase hauling power when raising or trimming sails.
WINDWARD: Toward the direction from which the wind is coming; opposite of leeward.


YACHT: A vessel of pleasure or state.
YARDARM: The extremities of a yard.
YAW: To swing off course, as when due to the impact of a following or quartering sea.
YAWL: A two-masted sailboat with the small mizzen mast stepped abaft the rudder post.


ZEBECK: A small three-masted Mediterranean vessel with lanteen and som square sails.
ZULU TIME: GMT- Greenwich Meridian Time, also known as Universal Time.