Sailing terms glossary
Plain-English definitions for the vocabulary on the ASA 101 written test. When you can use these without thinking, the rest of the exam gets much easier.
Directions and orientation
- Bow / stern
- The front / the back of the boat.
- Port / starboard
- Left / right when facing the bow. Port has four letters, like "left."
- Forward / aft
- Toward the bow / toward the stern.
- Abeam
- Off the side of the boat, at a right angle to its centerline.
- Windward
- Toward the wind; the side the wind hits first.
- Leeward
- Away from the wind; the sheltered, downwind side. The boom always rides to leeward.
- Beam
- The boat's width at its widest point.
- Draft
- How deep the boat reaches below the waterline.
- Freeboard
- The height of the hull above the waterline.
Hull and steering
- Hull
- The body of the boat.
- Keel
- The fixed fin under the hull. It resists sideways slip (leeway) and its ballast counteracts heeling.
- Centerboard
- A retractable keel-like fin on smaller boats.
- Rudder
- The underwater blade that steers the boat.
- Tiller
- The handle that turns the rudder. Push it one way and the bow goes the other.
- Helm
- The steering station (tiller or wheel) — or the person steering.
- Transom
- The flat back surface of the stern.
- Cockpit
- The recessed area where the crew sits and steers.
Rigging
- Mast
- The vertical spar the sails hang from.
- Boom
- The horizontal spar along the foot of the mainsail.
- Gooseneck
- The fitting that joins the boom to the mast.
- Standing rigging
- The fixed wires holding the mast up: shrouds (sides), forestay (bow), backstay (stern).
- Running rigging
- The lines you adjust while sailing: halyards and sheets.
- Halyard
- A line that raises and lowers a sail.
- Sheet
- A line that trims a sail in and out (mainsheet, jib sheets).
- Winch
- A drum that multiplies your pulling power on a loaded line.
- Cleat
- A fitting that holds a line fast.
- Block
- A pulley aboard a boat.
Sails
- Mainsail
- The principal sail, set behind the mast on the boom.
- Jib
- The triangular headsail set forward of the mast on the forestay. A large overlapping one is a genoa.
- Head / tack / clew
- The sail's corners: top / forward-bottom / aft-bottom.
- Luff / leech / foot
- The sail's edges: forward / aft / bottom.
- Batten
- A stiffening slat in a pocket on the leech of the mainsail.
- Telltales
- Bits of yarn or ribbon on the sail showing how air flows over it — your trim gauges.
- Luffing
- The flutter of a sail that's under-trimmed or pointed too close to the wind.
Points of sail and maneuvers
- Point of sail
- The boat's angle to the wind — see the full guide.
- No-go zone
- Roughly 45° either side of the wind where a boat cannot sail.
- In irons
- Stuck head-to-wind with no steerage, sails flapping.
- Close-hauled
- Sailing as close to the wind as possible, sheets in tight.
- Reach
- Sailing across the wind: close reach, beam reach, or broad reach.
- Run
- Sailing with the wind dead astern.
- Heading up
- Turning toward the wind.
- Bearing away / falling off
- Turning away from the wind.
- Tacking (coming about)
- Turning the bow through the wind onto the other tack. "Ready about" → "Helm's alee."
- Jibing
- Turning the stern through the wind. "Prepare to jibe" → "Jibe-ho." Control the boom.
- Beating
- Zig-zagging upwind in a series of tacks.
- Heeling
- The boat leaning over under wind pressure.
- Leeway
- Sideways slip downwind as you sail, resisted by the keel.
- Hove-to / heaving to
- Parking the boat by backing the jib and lashing the helm — a rest button on the water.
- By the lee
- Running with the wind coming over the same side the boom is on — accidental-jibe territory.
Wind
- True wind
- The wind over the water, as felt by something standing still.
- Apparent wind
- The wind you feel aboard — true wind combined with the wind made by the boat's own motion. It moves forward and strengthens as you speed up.
- Puff / lull
- A momentary increase / decrease in wind.
- Header / lift
- A wind shift that forces you to bear away / lets you point higher.
Rules and safety
- Stand-on vessel
- The boat that holds course and speed in a crossing situation.
- Give-way vessel
- The boat that must keep clear — early and obviously. See the right of way guide.
- PFD
- Personal flotation device. One wearable, USCG-approved PFD per person aboard.
- Bowline
- The knot that makes a secure loop that won't slip yet unties easily.
- Figure-eight knot
- A stopper knot tied in the end of a line so it can't run through a block.
- Cleat hitch
- The knot for securing a line to a cleat.
Docking and anchoring
- Fender
- A cushion hung between the hull and the dock.
- Dock line
- A line securing the boat to a dock; a spring line limits fore-and-aft movement.
- Mooring
- A permanent anchor-and-buoy a boat ties to.
- Rode
- The anchor line (and chain).
- Scope
- The ratio of rode let out to water depth — more scope, better holding.