BOAT TERMINOLOGY AND NAUTICAL TERMS

If you own a boat or are looking to own a boat, it helps to make yourself familiar with the most commonly used boating terms. Not only will you impress your friends, but knowing the correct terminology is important in staying safe on the waters. Below is a list of the most common words still in use today, many of which have their roots stretching far into the past when sea travel was our main mode of transportation. If you can't find the word you are looking for then please email us and we can add it to our list.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

Above Board -  On or above the deck, in plain view, not hiding anything.

Abaft - Toward the rear (stern) of the boat, relative to some object or position ("abaft the fore hatch").

Abandon ship!  - An imperative to leave the vessel immediately, usually in the face of some imminent danger.

Abeam  -  On the beam , a relative bearing at right angles to the centerline of the ship's keel.

Aboard - On or within the vessel.

Adrift  - Floating free with the currents and tide, said of a freely floating object or vessel which is not moving of its own power, floating at random.

Aft - At, near or towards the stern, to move aft is to move back.

Afloat - Of a vessel which is floating freely (not aground or sunk).

Aground - Touching or fast to the ground (usually involuntarily).

Ahead - Forward of the bow.

Ahoy - A cry to draw attention. Term used to hail a boat or a ship, as " Boat ahoy! "

Ahull - When the boat is lying broadside to the sea. It is a technique to ride out a storm with no sails and helm held to leeward.

Aid to Navigation (ATON) - Any device (i.e. sea markers, buoys, radio beacons, lighthouses) external to a vessel or aircraft specifically intended to assist navigators in determining their position or safe course, or to warn them of dangers or obstructions to navigation.

Alee - Away from the direction of the wind. Opposite of windward.

Aloft - Above the deck of the boat, usually overhead on the mast or in the rigging.

Alongside - By the side of a ship or pier.

Anchor - A heavy metal object designed to prevent or slow the drift of a ship.

Anchorage - A suitable place for a ship to anchor in relation to the wind, seas and bottom. Also, area of a port or harbor.

Anchor ball - Round black shape hoisted in the forepart of a vessel to show that it is anchored.

Anchor buoy - A small buoy secured by a light line to anchor to indicate position of anchor on bottom.

Ashore - On the beach, shore or land.

Astern - Backwards, towards the stern (rear) of a vessel, behind a vessel. Opposite of ahead.

Awash - So low in the water that the water is constantly washing across the surface.

Autopilot - An instrument - may be electronic or mechanical - used to automatically steer the vessel on a predetermined course through the water.

B

Back and fill - To use the advantage of the tide being with you when the wind is not.

Bailer - A device for removing water that has entered the boat.

Bank - A large area of elevated sea floor.

Bar - Large mass of sand or earth, formed by the surge of the sea. They are mostly found at the entrances of great rivers or havens, and often render navigation extremely dangerous, but confer tranquility once inside.

Bar Pilot - A bar pilot guides ships over the dangerous sandbars at the mouth of rivers and bays.

Batten down the hatches - Secure hatches and other loose objects within hull and on deck, to prepare for inclement weather.

Beam - The greatest width of the boat.

Bear down or bear away - Turn away from the wind.

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.

Berth - A bed or sleeping accommodation on a boat or ship; a place where the ship can tie up or anchor; safe and cautious distance to keep between two passing vessels, as in ‘giving a wide berth'.

Bilge - The compartment at the bottom of the hull of a ship or boat where water collects and must be pumped out of the vessel.

Bitter End - The last part or loose end of a rope or cable. The inboard end of the anchor rode.

Boat - A  very broad term for a waterborne vehicle smaller than a ship. 

Boom  - A pole running at a right angle from the mast.

Bow - The front of a ship.

Broach - When a sailing vessel loses control of its motion and is forced into a sudden sharp turn, often heeling heavily and in smaller vessels sometimes leading to a capsize.

Bulkhead - An upright wall within the hull of a ship separating its compartments.

Buoy - A floating object which is anchored at a given position and serves as an aid to navigation or for mooring.

Burgee - A small flag, typically triangular, flown from the masthead of a yacht to indicate yacht-club membership.

Burdened Vessel - A 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 vessel".   

C

Cabin  - an enclosed room on a  deck or flat.

Cable  - A large rope.

Capsize  - When a ship or boat lists too far and rolls over, exposing the keel. On large vessels, this often results in the sinking of the ship.

Careening  - Tilting a ship on its side, usually when beached, to clean or repair the hull below the water line.

Catamaran  - A vessel with two hulls.

Centreboard  - A board or plate lowered through the hull of a  dinghy  on the centreline to resist leeway.

Chafing  - Wear on line or sail caused by constant rubbing against another surface.

Chafing gear - Material applied to a line or spar to prevent or reduce chafing.

Chain locker  - A space in the forward part of the ship, typically beneath the bow in front of the foremost collision bulkhead, that contains the anchor chain when the anchor is secured for sea.

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.

Compass  - Navigational instrument showing the direction of the vessel in relation to the Earth's  geographical poles  or  magnetic poles.

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 - The raised edge of a hatch, cockpit or skylight to help keep out water.

Cockpit - The location from which the boat is steered, usually in the middle or at the stern of the boat.

Coil - To lay a line down in circular turns.

Course - The direction in which a vessel is steered.

Cuddy - A small sheltered cabin on a boat.

Current - The horizontal movement of water.  

D

Davit - Device (like a small crane) for lifting a tender on and off a boat.

Dead ahead  - Exactly ahead, directly ahead, directly in front.

Dead Astern - A position directly aft or behind the vessel.

Dead Reckoning - Navigating.

Deadrise  - The design angle between the keel and horizontal.

Deadwood  - A wooden part of the centerline structure of a boat, usually between the sternpost and amidships.

Decks  - A permanent covering over a compartment, hull or any part of a ship serving as a floor.

Deck hand  - A person whose job involves aiding the deck supervisor in (un)mooring, anchoring, maintenance, and general evolutions on deck.

Deck supervisor  - The person in charge of all evolutions and maintenance on deck; sometimes split into two groups: forward deck supervisor, aft deck supervisor.

Deckhead  - The under-side of the deck above.

Dinghy - A small open boat. A dinghy is often used as a tender for a larger craft.

Displacement - The weight of a floating boat measured as the weight of the amount of water it displaces. A boat displaces an amount of water equal to the weight of the boat, so the boat's displacement and weight are identical.

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  or  draught  - The depth of a ship's keel below the waterline.

E

Ebb - A receding current, when the falling tide recedes out to sea and the water level lowers.

Echo sounding  - Measuring the depth of the water using a  sonar  device.

Embayed  - The condition where a sailing vessel is confined between two capes or headlands by a wind blowing directly onshore.

Ensign - A flag indicating the nationality of a vessel.

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.

F

Fast  - Fastened or held firmly ( fast aground : stuck on the seabed;  made fast : tied securely).

Fathom  - A unit of length equal to 6 feet (1.8 m), roughly measured as the distance between a man's outstretched hands. Particularly used to measure depth.

Fender  - An air or foam filled bumper used in boating to keep boats from banging into docks or each other.

Fetch  - The distance across water which a wind or waves have travelled; to reach a mark without tacking.

Flank  - The maximum speed of a ship. Faster than "full speed".

Flare  - A pyrotechnic signalling device, usually used to indicate distress. Also - the outward curve of a vessel's sides near the bow.

Flood/Flow - An incoming current.

Following sea  - A sea with waves approaching from the stern of the boat; a sea in which the waves are moving in the same direction as the vessel.

Fore or Foreward  - Towards the bow.

Fore & Aft - In a line parallel to the keel.

Forefoot  - The lower part of the stem of a ship.

Forepeak - A compartment in the bow of a small boat.

Fouled - Any piece of equipment that is jammed, clogged, entangled or dirtied.

G

Galley  - the kitchen of the ship.

Gangplank  - A movable bridge used in boarding or leaving a ship at a pier.

Gangway  - An opening in the bulwark of the ship to allow passengers to board or leave the ship.

Ghost  - To sail slowly when there is apparently no wind.

Give-way (vessel)  - Where two vessels are approaching one another so as to involve a risk of collision, this is the vessel which is directed to keep out of the way of the other. Also known as the “burdened vessel”.

Global Positioning System (GPS)  - A satellite based radionavigation system providing continuous worldwide coverage. It provides navigation, position, and timing information to air, marine, and land users.

Grab Rails - Hand-hold fittings mounted on cabin tops and sides for personal safety when moving around the boat.

Ground  - The bed of the sea.

Grounding  - When a ship (while afloat) touches the bed of the sea, or goes "aground”.

Ground Tackle - A collective term for the anchor and its associated gear.

Gunwales - The upper edge of a boat's sides.

Gybe  or  jibe  - Turning the boat so that the stern crosses the wind, changing direction.  

H

Harbor  - A harbor or harbour, or haven, is a safe place to anchor, protected from the weather. Harbours can be man-made or natural and are used for docking and loading.

Harden up  - Turn towards the wind; sail closer to the wind.

Hatchway/Hatch  - A covered opening in a ship's deck through which cargo can be loaded or access made to a lower deck; the cover to the opening is called a hatch.

Hauling wind  - Pointing the ship towards the direction of the wind; generally not the fastest point of travel on a sailing vessel.

Hawse pipe ,  hawse-hole  or  hawse - The shaft or hole in the side of a vessel's bow through which the anchor chain passes.

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.

Head Sea  - A sea where waves are directly opposing the motion of the ship.

Headway - The forward motion of a boat. Opposite of sternway.

Heave  - A vessel's transient, vertical, up-and-down motion.

Heave to - Steering into the wind and sea, making minimum headway.

Helm - The wheel or tiller controlling the rudder.

Helmsman  - A person who steers a ship.

Hitch  - A knot used to tie a rope or line to a fixed object.

Hull  - The main body of the vessel.

I

Inboard - Toward the center of a vessel; inside.

Inboard motor  - An engine mounted within the hull of a vessel, usually driving a fixed propeller by a shaft protruding through the stern. Generally used on larger vessels.

In irons  - When the bow of a sailboat is headed into the wind and the boat has stalled and is unable to manoeuvre.

J

Jacobs Ladder - A rope ladder, lowered from the deck, as when pilots or passengers come aboard.

Jetsam  - Debris ejected from a ship that sinks or washes ashore. See also flotsam .

Jibe  or Gybe - Turning the boat so that the stern crosses the wind, changing direction.  

Jetty - A structure, usually masonry, projecting out from the shore; a jetty may protect a harbor entrance.

K

Keel  - The central structural basis of the hull.

Knot  - A unit of speed: 1 nautical mile (1.8520 km; 1.1508 mi) per hour. Originally speed was measured by paying out a line from the stern of a moving boat. The line had a knot every 47 feet 3 inches (14.40 m), and the number of knots passed out in 30 seconds gave the speed through the water in nautical miles per hour.

Know the ropes  - A sailor who 'knows the ropes' is familiar with the miles of cordage and ropes involved in running a ship.

L

Land Lubber   - A person unfamiliar with being on the sea.

Lanyard  - A rope that ties something off.

Latitiude - The distance north or south of the equator measured and expressed in degrees.

Lazarette  - Small stowage locker at the aft end of a boat.

League - A unit of length, normally equal to 3 nautical miles.

Lee side  - The side of a ship sheltered from the wind.

Leeway   - The sideways movement of the boat caused by either wind or current.

Lee ward - On or toward the side to which the wind is blowing. Opposite of windward.

Length overall , LOA  - the total length of a boat.

Lifebelt , lifejacket, life preserver or Mae West  - A device such as a buoyant ring or inflatable jacket which keeps a person afloat in the water.

Lifeboat - A small, often inflatable vessel kept on board a ship and used to take crew and passengers to safety in the event of the ship being abandoned.

Life Buoy - Floating safety ring to assist in a person overboard.  

Line  - the correct nautical term for the majority of the cordage or "ropes" used on a vessel. A line will always have a more specific name, which describes its use.

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. 

Lubbers 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.

M

Mainsheet - Line that controls the position of the mainsail.

Making Way - Vessel under way and moving through the water.

Man overboard !  - A cry let out when a person has gone 'overboard' (fallen into the water).

Marina - A place where boats can find fuel, water and other services.

Mark - An object used as a reference point while navigating.

Marlin Board - Like a swim board.  A small deck on the aft (rear) of the boat to make accessing the water easier.

Mast  - A vertical pole on a ship which supports sails or rigging.

Mess  - An eating place aboard ship. A group of crew who live and feed together.

Midship - Approximately in the location equally distant from the bow and stern.

Mile  - see  nautical mile .

Moor  - to attach a boat to a mooring buoy or post. Also, to dock a ship.

N

Nautical mile  - A distance of 1.852 kilometres (1.151 mi). Approximately the distance of one  minute of arc  of  latitude  on the Earth's surface. A speed of one nautical mile per hour is called a  knot.

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 - Rules governing the movement of vessels in relation to each other, provide guidance on how to avoid a collision and are also used to assign blame when a collision does occur.

O

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 motor  - A motor mounted externally on the transom of a small boat. The boat may be steered by twisting the whole motor, instead of or in addition to using a rudder.

Outward bound  - To leave the safety of port, heading for the open ocean.

Overboard - Over the side or out of the boat.

Overhaul  - Hauling the buntline ropes over the sails to prevent them from chaffing.

Outhaul - An adjuster that tensions the sail's foot.

Overhead  - The "ceiling," or, essentially, the bottom of the deck above you.

P

Personal Flotation Device (PFD) - 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.

Piot  - Navigator. A specially knowledgeable person qualified to navigate a vessel through difficult waters, e.g. harbour pilot etc.

PIM  - Points (or plan) of intended movement. The charted course for a naval unit's movements.

Pitch - A vessel's motion, rotating about the beam axis, so the bow pitches up and down.

Planing - When a fast-moving vessel skims over the water instead of pushing through it.

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  - Towards the left-hand side of the ship facing forward. Denoted with a red light at night.

Porthole  - an opening in a ship's side, typically a round one for admitting light and air, fitted with thick glass and, often, a hinged metal cover, a window.

Port Tack  - Sailing with the wind coming from the port side of the vessel. Must give way to boats on  starboard tack .

Privileged Vessel - A vessel which, according to the applicable Navigation Rule, has right-of-way.

Personal Watercraft (PWC) - i s a recreational vessel that is: power driven, has a fully enclosed hull, does not retain water when capsized and is designed to be operated by a person standing, sitting astride or kneeling on the vessel, but not inside the vessel. I.e. a Jet Ski.

Q

Quayside  - Refers to the dock or platform used to fasten a vessel to.

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

R

Radar  - Acronym for RAdio Detection And Ranging. An electronic system designed to transmit radio signals and receive reflected images of those signals from a "target" in order to determine the bearing and distance to the "target".

Radar reflector  - A special fixture fitted to a vessel or incorporated into the design of certain aids to navigation to enhance their ability to reflect radar energy. In general, these fixtures will materially improve the visibility for use by vessels with radar.

Reaching  - Sailing across the wind: from about 60° to about 160° off the wind. Reaching consists of "close reaching" (about 60° to 80°), "beam reaching" (about 90°) and "broad reaching" (about 120° to 160°).

Reefing - To temporarily reduce the area of a sail exposed to the wind, usually to guard against adverse effects of strong wind or to slow the vessel.

Rigging  - The system of masts and lines on ships and other sailing vessels.

Ropes  - 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/longitudinal 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.

S

Sail Trim - The position of the sails relative to the wind and desired point of sail.

Sandbar - 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.

Seacock  - a  valve  in the  hull  of a boat for drainage to the sea.

Sea Room - A safe distance from the shore or other hazards.

Sea anchor  - A stabilizer deployed in the water for  heaving to  in heavy weather. It acts as a brake and keeps the hull in line with the wind and perpendicular to waves. Often in the form of a large bag made of heavy canvas.

Seamanship - All the arts and skills of boat handling, ranging from maintenence and repairs to piloting, sail handling and rigging.

Seaworthy - Certified for, and capable of, safely sailing at sea.

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. 

Skipper  - The  captain  of a ship.

Slack - Not fastened; loose. Also, to loosen. 

Sole - Cabin or saloon floor. Timber extensions on the bottom of the rudder. Also the melded fibreglass deck of a cockpit.

Sounding - Measuring the depth of the water, traditionally done by swinging the lead, now commonly by echo sounding.

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.

Sponson - Projection from side of ship, as protection, gun platform, etc. 

Squall - A sudden, violent wind often accompanied by rain.

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.

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. Denoted with a green light at night.

Starboard tack  - Wind across the starboard (right) side. Has right of way over boats on port tack.

Stem - The forward most part of the bow.

Stern - The rear part of a ship, technically defined as the area built up over the sternpost, extending upwards.

Stern Line - A docking line leading from the stern.

Strong Wind Warning - Small craft warnings of strong winds are issued whenever mean winds exceeding 25 knots are expected.

Stow - To put an item in its proper place.

Surge  - A vessel's transient motion in a fore and aft direction.

Sway  - A vessel's lateral motion from side to side.

Swamp - To fill with water, but not settle to the bottom.

Swimboard - A platform at the back of a boat to allow easy access to the water.

T

Thwartships - At right angles to the centreline 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.

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 bearing  - An absolute bearing using true north.

True north  - The direction of the geographical  North Pole.

U

Underway - A vessel that is moving under control. I.e. when not moored, at anchor or aground.

V

Vanishing angle   - The maximum degree of heel after which a vessel becomes unable to return to an upright position.

V Hull - 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 (1.8x1.2m) 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.

W

Weather side   - The side of a ship exposed to the wind.

Wake - Turbulence behind a vessel. Not to be confused with   wash .

Wash - The waves created by a vessel. Not to be confused with   wake .

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.

Waypoint - A location defined by navigational coordinates, especially as part of a planned route.

Winward - Toward the direction from which the wind is coming.

Y

Yacht - A pleasure vessel, a pleasure boat; conveys the idea of size and luxury, can be either sail or power.

Z

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