Boat Terminology
Part I

In this boat terminology-list I have included all the boating and sailing terms alphabetically. Scroll down through them until you find the one you're looking for!


  • Abeam: At right angles to the fore and aft line of the boat. 'On the beam' means the same.
  • Ahead: The direction directly in front of the boat.
  • Aloft: Above deck level or up the mast.
  • Anchor buoy: It's a small buoy that is attached to the tripping line (which is connected with the crown-part of an anchor to make anchor retrieval easier.)
  • Anchor light: A white all-round light hoisted up the mast or positioned at the top of the mast.
  • Anchor roller: A roller at the bow of a boat over which the anchor cable is run.
  • Astern: Direction directly behind the boat.


  • Back: When the wind backs, it means that it shifts direction in a counter-clockwise direction.
  • Bar: An area near the mouth of a river where the water flow causes silting, resulting in a shallow patch.
  • Batten: A stiff slat used to control the curve of a sail.
  • Batten pocket: A pocket on a sail where the batten is inserted.
  • Beam: The width of a boat.
  • Beam reach: A point of sailing with the apparent wind on the beam.
  • Bear away: To alter course away from the wind.
  • Bearing: The direction, measured in degrees, from the observer to the object described.
  • Beat: To sail on alternate tacks towards a position that is upwind of the boat.
  • Bilge: The area of a boat underneath the cabin floor.
  • Bilge pump: A manual or electrical pump designed to empty the bilge.
  • Binnacle: A structure near the helmsman's position housing the compass and instrumentation.
  • Black ball: A single ball hoisted on a vessel that indicates that the vessel is at anchor.
  • Boat hook: A hook on a pole used to pick up mooring buoys or ground lines when mooring mediterranean style.
  • Boom vang: A device to pull the boom down in order to flatten the mainsail.
  • Bottle-screw: A screw fitting on guardrails, shrouds and stays. It's used to tension the wire.
  • Breast ropes: Mooring lines run at right angles to the fore and aft line of the boat.
  • Broach: This happens when, in a heavy following sea, the boat slew round towards the wind.
  • Broad reach: A point of sailing between running and beam reaching.
  • Broken water: An isolated area of the sea with small breaking waves. This happens often when a strong tide flows over a rough seabed.
  • Bulkhead: A partition built across the width of the hull.
  • Burgee: A small triangular flag flown to indicate membership of a sailing club or organisation.


  • Cable: A distance of one tenth of a nautical mile. So, approximately 185 metres.
  • Calm: A state when the sea is smooth with little or no wind.
  • Cast off: An instruction to release or let go a rope or line.
  • Centre of buoyancy: This is the geometric centre of that part of the hull that is below the waterline.
  • Centre of gravity: A theoretical position where the weight of a vessel appears to be centered.
  • Chain plate: A metal strip on the hull to which the shrouds are attached.
  • Chart datum: The level from which depth soundings are measured. It's close to the minimum height of low water springs.
  • Cleat: A fitting for securing lines and ropes.
  • Clew: The lower aft corner of a sail.
  • Clew outhaul: A line attached to the clew of a mainsail to tension the foot of the sail.
  • Close hauled: A point of sailing as close to the wind as possible.
  • Cocked hat: A triangle formed on the chart when three position lines are drawn. It gives some indication of the size of the measurement error.
  • Course made good: The course over the seabed. The resultant of heading, leeway and tidal movement.
  • Current: The movement of water caused by geographical features.

Go to Boat Terminology Part II

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