Words and expressions on the water
Boating glossary A–Z – words and expressions on the water
132 boating terms. Short explanations, from aft to bailer.
A
- Stern
The rear part of the boat.
- Aft deck
The deck area at the very back of the boat.
- Stern mooring
Mooring stern-to the jetty.
- Stern light
Light showing white astern under the conditions set out in the Collision Regulations.
- Transom
The flat surface at the stern end of a hull, often where an outboard is mounted.
- Anchor
Gear that grips the bottom and holds the boat in place.
- Anchor line
Flat webbing used instead of a traditional anchor rode.
- Windlass
Device that helps haul in and pay out the anchor rode or chain.
- Leeway
Sideways movement away from the intended course, for example due to wind.
- Bleeding
Opening or line that lets air out of or into a system, such as a tank.
B
- Port
The left side of the boat when facing the bow.
- Backfire
Gearbox that transfers engine power to the propeller shaft and lets you select forward, neutral or reverse.
- Swim platform
Platform at the stern for swimming, boarding and working close to the water.
- Balanced rudder
A rudder with part of the blade forward of the rudder stock, which reduces the force needed to steer.
- Ballast
Weight that helps keep the boat stable, for example in a sailboat's keel.
- Battery isolator switch
A switch that can disconnect a battery from the connected electrical circuits.
- Close-hauled
Sailing at an angle into the wind, as close to the wind direction as the boat and sails allow.
- Bimini
Canvas sun awning over the cockpit or deck.
- Boom
Spar that extends the foot of the sail.
- Antifouling
Paint for the part of the hull below the waterline. Which products may be used depends on factors such as where the boat is used.
- Seacock
Valve on a through-hull fitting below the waterline, for example the engine's raw water intake.
- Gross weight
What a vehicle actually weighs at a given moment, including the load.
- Boat hook
Pole with a hook that helps you catch a line or reach a mooring point.
- Bellows
Pleated, flexible boot or seal. Drives have several bellows with different functions.
- Bearing
The direction from your position to an object or another position.
D
- Displacement
The boat's mass when afloat in a given load condition; equal to the mass of the water it displaces.
- Displacement hull
Hull supported mainly by buoyancy rather than by planing.
- Hard (tight)
Fully, or as far as it will go, as in hard to starboard for a large rudder angle.
- Nautical mile
Another name for a nautical mile or sea mile: 1,852 metres.
- Draft
The vertical distance from the waterline to the lowest point of the boat.
- Drives
Drive unit with gearcase and propeller that transfers the engine's power to the water.
- Floorboards
The floor of the boat, for example in the cockpit or the cabin.
- Deck
The upper surface covering all or part of the hull.
E
- Depth sounder
An instrument that uses sound pulses and their echoes to measure depth and show objects underwater.
F
- Halyard
A line used to hoist a sail or a flag.
- Fender
Soft protection between the boat and a jetty or another boat.
- Flybridge
An open helm station on top of the superstructure of a motorboat.
- Life jacket
Buoyancy aid worn on the body. Different types work differently and are intended for different uses.
- Freeboard
The height from the waterline up to the deck edge at the side of the boat.
- Neutral
Gear position in which the engine does not drive the propeller.
- Freshwater cooling
Cooling system in which the engine's internal coolant transfers heat to raw water through a heat exchanger.
- Bow
The front part of the boat.
- Forepeak
The space furthest forward inside the boat.
- Headsail
Sail set forward of the mast, such as a jib or genoa.
- Forestay
Wire or other rigging that supports the mast forward.
- Mooring
Lines and fittings that hold the boat in place at a dock, buoy or other fixed point.
G
- Gaff
Line that holds or controls the position of a boom or pole, such as the spinnaker pole.
- Genoa
Large headsail whose leech extends aft of the mast.
- Gipp
Manoeuvre in which a sailboat changes tack with the wind from astern, and the mainsail swings across to the other side.
- Transducer
Part of an instrument that measures a quantity, such as temperature or depth.
- Guest harbour
Harbour with berths intended for visiting boats.
H
- Half hitch
A simple turn of a line around itself or an object, often as part of a knot.
- Harbour canopy
Cover that protects the open areas of a moored boat.
- Wrist strap
Strap around the wrist to keep hold of a handheld item.
- Rudder stock
The shaft the rudder blade is attached to and pivots around.
I
- Impeller
Rotating pump wheel. In the raw water pump of many marine engines it is a flexible wheel with rubber vanes.
- Inboard
Engine mounted inside the boat, driving the propeller via a shaft or sterndrive, for example.
K
- Cabin
Enclosed space on board for spending time or sleeping overnight.
- Canopy
Removable canvas cover that protects parts of the boat from the weather.
- Universal joint
A joint in a rotating shaft connection that can transmit power even when the shafts are at an angle.
- Knap
Fitting with two horns that you can take a line around when mooring.
- Knots
A speed of one nautical mile per hour, exactly 1.852 km/h. The word is also used for a knotted connection in a line.
- Berth
A sleeping place on a boat.
- Compass
Instrument that shows direction using the magnetic field or another reference.
- Beating
Sailing upwind by alternating between close-hauled tacks.
- Course
The direction the boat is steering or intended to travel.
- Keel
Longitudinal member along the very bottom of the hull; on many sailboats also the protruding part that provides lateral resistance and carries ballast.
- Keelson
Internal longitudinal reinforcement above the keel. The word is also used for the space where bilge water collects.
L
- Shore power
Electrical connection from shore to a moored boat.
- Navigation lights
Light on a vessel that, under the collision regulations, helps others judge things such as its position and heading.
- Latitude
A position's distance north or south of the equator, expressed as an angle.
- Line
Rope on board, for example for mooring or sail handling.
- Log
Instrument that measures speed through the water or distance travelled.
- Longitude
A position's angle east or west of the prime meridian.
- Windward
The side or direction the wind is coming from.
- Leeward
The side facing away from the wind; also an area sheltered from the wind.
- Bilge
Sailing with the wind directly or almost directly astern.
- Bilge pump
Pump that removes water that has collected inside the boat.
M
- Guardrail
Wire or line along the sides of the deck that forms part of the boat's guardrail.
- Cruising speed
The speed you normally choose for longer runs, taking into account comfort and fuel consumption, among other things.
- Mast
Vertical spar that carries the sails and rigging.
N
- Nautical mile
The nautical mile, a unit of length of exactly 1,852 metres.
O
- Sacrificial anode
A metal part that deliberately corrodes to help protect other metal parts from galvanic corrosion.
P
- Stuffing box
Seal around a shaft, for example where the propeller shaft passes through the hull.
- Galley
The boat's galley.
- Planing
Speed regime in which a significant part of the boat's weight is carried by the hydrodynamic lift generated as the hull moves through the water.
- Chartplotter
Electronic navigation instrument that shows your position and other information on a digital chart.
- Bollard
A sturdy fitting or post that a mooring line can be put around.
- Propeller
Rotating bladed part that generates thrust in the water.
- Propeller shaft
Shaft that transmits rotation from the engine or gearbox to the propeller.
- Propeller slip
The difference between the propeller's theoretical advance and the measured speed, expressed as a percentage of the theoretical speed.
- Bow pulpit
Railing at the bow, often made of metal tubing.
- Pushpit
Railing at the stern, often made of metal tubing.
R
- Guardrail
The top edge of the boat along the sides.
- Reef
Reducing sail area by taking in or furling part of the sail.
- Rig
Mast, boom and the lines and wires that support and control the sails.
- Rudder
Steering surface in the water that is turned to change the boat's direction.
- Tiller
Lever connected directly to the rudder or to an outboard's steering.
- Cabin
Enclosed space where you can stay or sleep.
S
- Saildrive
Drive unit on an inboard engine that passes down through the hull bottom and carries the propeller beneath the boat.
- Gunwale
Raised rim around, for example, a cockpit or opening.
- Shackle
Openable metal fitting with a bolt or screw pin for connecting parts.
- Holding tank
Tank that collects toilet waste on board.
- Cockpit
Recessed, open part of the boat where the crew can sit and handle the boat.
- Nautical miles
Nautical unit of length equal to exactly 1,852 metres.
- Launching
Putting the boat back in the water after storage ashore.
- Raw-water cooling
Cooling where water from outside the boat is used in the engine's cooling system, either directly or via a heat exchanger.
- Sheet
Line that controls the angle of a sail to the wind.
- Hull
The boat's load-bearing outer shell, which keeps the water out and provides buoyancy.
- Through-hull fitting
Fitting where a hose or line passes through the hull.
- Dab
Fixed, fin-like part under the boat or a drive that can provide directional stability or protection.
- Stroke
Sailing manoeuvre where the bow passes through the wind and the wind comes in from the other side.
- Broad reach
Sailing with the wind on the quarter.
- Snipa (Swedish double-ended motor launch)
Traditional boat type with rounded hull lines, often with a pointed or rounded stern.
- Spring line
Mooring line run diagonally along the boat to limit its movement forward or aft.
- Strut
Rigging that supports the mast fore and aft.
- Pitch
The theoretical distance a propeller would advance in one revolution with no slip.
- Starboard
The right-hand side of the boat when you face the bow.
- Pump-out
Emptying the boat's holding tank by pumping the waste out to a pump-out station.
- Swivel
Rotating fitting that lets two connected parts turn independently of each other.
T
- Thermostat
Temperature-controlled valve that regulates the path or flow of coolant in an engine.
- Mooring
The manoeuvre of bringing a boat alongside a jetty or other mooring.
- Total weight
The vehicle's kerb weight plus the maximum permitted load. Registered gross weights are used to determine driving licence requirements.
- Trim
The boat's fore-and-aft attitude, or an adjustment that affects how the boat, drive or sails perform.
U
- Outboard
Engine and drive unit built as a single assembly mounted outside the hull, usually on the transom.
- Gear ratio
The ratio between input and output speed (rpm) in a power transmission.
V
- Shroud
Rigging that supports the mast sideways.
- Waterline
The line where the water surface meets the hull when the boat is afloat.
- Winterizing
Steps that protect the engine and other systems during winter storage.
- Heat exchanger
A device that transfers heat between two fluid circuits without the fluids mixing.
Å
- Oar
Implement that rests in a rowlock and is used to propel a boat by muscle power.
Ö
- Bailers
A small container used to bail water out of the boat.