Sailing terms and nautical glossary
Find clear definitions of sailing terms, boat parts, knots, navigation and nautical abbreviations. New to sailing? Start with the everyday words below, then explore the full glossary by subject or search for a term.
Sailing terms for beginners
Begin with port and starboard, bow, windward and leeward. Learn how sheets and halyards control sails, then explore points of sail, tacking and gybing.
For terms in context, read our beginner sailing vocabulary guide. Ready to practise on the water? Our first sailing course guide explains how to choose a starting route.
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TermDefinition
- General Nautical Terminology, Nautical Topics, Navigation Rhumb Line
A path on the Earth's surface that crosses every meridian at the same angle.
A rhumb line represents a constant true course on an idealised...
More Details - General Nautical Terminology, Nautical Topics, Points of Sail Ride Height
The vertical clearance at which a foiling craft operates above the water surface.
Ride height is governed by foil lift, speed, loading and the...
More Details - General Nautical Terminology, Nautical Topics, Parts of a Boat, Safety Riding Turn
A turn of rope trapped beneath or crossed by another loaded turn on a winch or drum.
It forms when incoming rope overrides an earlier turn,...
More Details - General Nautical Terminology, Nautical Topics, Parts of a Boat, Points of Sail, Safety Rigging
The system of spars, stays, shrouds, lines and fittings that supports and controls a vessel's sails or other elevated equipment.
Standing...
More Details - General Nautical Terminology, Nautical Topics, Parts of a Boat, Points of Sail, Safety Rigging
The system of lines, wires, spars and fittings that supports and controls a vessel's masts and sails.
Standing rigging supports the mast and...
More Details - General Nautical Terminology, Nautical Topics, Parts of a Boat Rigging Screw
A threaded fitting used to adjust the effective length and tension of a stay or shroud.
Oppositely threaded ends allow adjustment by turning...
More Details - General Nautical Terminology, Nautical Topics, Safety Righting Lever
The horizontal distance between the lines of action of buoyancy and weight when a vessel is heeled.
Usually denoted GZ, it multiplied by...
More Details - General Nautical Terminology, Nautical Topics, Parts of a Boat, Points of Sail Righting Moment
The turning effect that tends to return a heeled vessel towards upright.
For a displacement vessel at a stated heel angle, it is related to...
More Details - General Nautical Terminology, Nautical Topics, Parts of a Boat, Safety Rigid Inflatable Boat
A lightweight powerboat with a rigid hull surrounded by inflatable buoyancy tubes.
Commonly abbreviated to RIB, the design combines the shaped...
More Details - General Nautical Terminology, Nautical Topics, Organisation, Parts of a Boat RINA
An international professional institution advancing naval architecture and associated maritime engineering.
The Royal Institution of Naval...
More Details - General Nautical Terminology, Nautical Topics, Navigation, Safety Risk of Collision
A situation in which the available information indicates that two vessels may collide unless appropriate action is taken.
A steady or nearly...
More Details - General Nautical Terminology, Nautical Topics, Signals & Communication Letter R (Flag Semaphore)
A two-flag semaphore position representing the letter R.
The signaller holds one flag in each hand at the prescribed angles illustrated in the...
More Details - General Nautical Terminology, Nautical Topics, Signals & Communication Letter R (Morse Code)
The International Morse Code letter R, represented by dot dash dot (.-.).
A dot lasts one signal unit and a dash three. Elements within this...
More Details - General Nautical Terminology, Nautical Topics, Organisation, Safety RNLI
An independent charity providing lifeboat search-and-rescue, seasonal lifeguarding and water-safety services in the United Kingdom and...
More Details - General Nautical Terminology, Nautical Topics, Parts of a Boat, Points of Sail Roach
The area of sail extending beyond a straight line drawn between the head and clew along the leech.
A positive roach adds area and is commonly...
More Details - General Nautical Terminology, Nautical Topics, Navigation, Weather (Meteorology) Rockall
A Met Office Shipping Forecast sea area in the North Atlantic west and northwest of Ireland.
Named after the Rockall islet, it lies north of...
More Details - General Nautical Terminology, Nautical Topics, Parts of a Boat, Safety, Signals & Communication Rocket Parachute Flare
A rocket-propelled pyrotechnic distress signal that deploys a bright red flare beneath a parachute at height.
Its altitude, luminous intensity...
More Details - Abbreviation, General Nautical Terminology, Nautical Topics, Depths & Clearance, Navigation Rock Seabed (R)
The code R identifies rock as the nature of the seabed or a rock feature.
Its position and the surrounding symbol distinguish it from R...
More Details - General Nautical Terminology, Nautical Topics, Parts of a Boat, Points of Sail, Safety Roller Furling
A system that stows a sail by rolling it around a stay, foil, spar or mandrel.
Headsail furlers commonly rotate a foil or drum around the...
More Details - General Nautical Terminology, Nautical Topics, Parts of a Boat, Points of Sail, Safety Roller Reefing
Reducing a sail's exposed area by partially rolling it around or into a stay, foil, mast or boom.
Unlike complete roller furling, roller...
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