Sailing terms glossary and visual quiz
Plain-English definitions for the vocabulary on the ASA 101 written test. Search the glossary, practice recall, then click the correct spot on a boat diagram until the words connect to real hardware.
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Term trainer
Visual boat-language hotspot quiz
Read the target term, then click the matching place on the boat. Wrong clicks are saved as weak visual terms.
Weak visual terms
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.
- Deck
- The working surface on top of the hull.
- 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.
- Cabin
- The enclosed space below or partly above deck.
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).
- Spreader
- A spar projecting from the mast that holds shrouds outboard for a stronger support angle.
- Chainplate
- A strong fitting where a shroud or stay attaches to the hull or deck.
- Stanchion / lifeline / pulpit
- Posts, wires, and bow/stern rails that help keep crew aboard.
- 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.
- Fairlead
- A fitting or guide that leads a line in the correct direction.
- Block
- A pulley aboard a boat.
- Shackle
- A metal connector with a pin, used to attach hardware or lines.
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.
- Hank
- A clip that attaches a jib to the forestay on hank-on sails.
- Roller furler
- A drum/foil system that rolls a headsail around the forestay.
- Downhaul / Cunningham
- A control that tensions the luff of a sail downward.
- Outhaul
- A control that pulls the clew aft and tensions the foot of the mainsail.
- Boom vang
- A control from mast base to boom that keeps the boom from lifting and controls leech tension.
- Traveler
- A track that moves the mainsheet attachment side to side for boom position and sail shape control.
- Topping lift
- A line that supports the boom when the sail is lowered or not carrying the boom.
- 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.
- Weather helm
- The tendency of the boat to turn toward the wind, often from sail imbalance or too much heel.
- Leeway
- Sideways slip downwind as you sail, resisted by the keel.
- Reefing
- Reducing sail area to keep the boat controlled in stronger wind.
- 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.
- Wing-on-wing
- A downwind setup with the mainsail on one side and the headsail on the other.
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.
- Throwable PFD
- A cushion or ring-style flotation device meant to be thrown to someone in the water.
- Float plan
- A written or texted plan left with someone ashore: crew, boat, route, return time, and who to call if overdue.
- Navigation lights
- Red port sidelight, green starboard sidelight, and white stern or all-round lights shown when required.
- Visual distress signal
- A flare, light, flag, smoke, or other approved signal used to attract help.
- 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.
- Round turn and two half hitches
- A secure way to tie a line around a post, ring, or rail.
- Clove hitch
- A quick temporary hitch around a rail, post, or stanchion.
- Square / reef knot
- A light-duty knot for temporarily joining two similar lines; not for critical loads.
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.
- Spring line
- A diagonal dock line that prevents the boat from moving forward or aft along the dock.
- 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.