Encyclopedia
Sail terms, explained by the people who cut them.
43 terms, one page each. Every diagram is drawn from the same geometry we build to - when a page defines the leech, the sail beside it has its own leech traced in red. And because we work in Dutch and Spanish as well as English, the words come in three languages.
Parts of a sail
Luff
The leading edge of a sail - the one that meets the wind first.
Voorlijk · GrátilLeech
The trailing edge, from head to clew - where the wind leaves the sail.
Achterlijk · BalumaFoot
The bottom edge of a sail, running from tack to clew.
Onderlijk · PujamenHead
The top corner of a triangular sail, where the halyard lifts it.
Tophoek · Puño de drizaTack
The forward bottom corner - where the sail is pinned down.
Halshoek · Puño de amuraClew
The aft bottom corner, where the sheet pulls.
Schoothoek · Puño de escotaRoach
The extra sail area outside the straight line from head to clew.
Gilling · AlunamientoMeasurements & numbers
Mid-girth
The width of a sail at half its height - the number that defines a downwind sail.
Halve breedteFoot median
The distance from the head to the midpoint of the foot.
OnderlijkzwaartelijnLuff perpendicular (LP)
The shortest distance from the clew to the luff - the number behind "150% genoa".
P, E, I and J
The four letters that describe your rig - and the first thing any sailmaker asks for.
Sail area
How much cloth is in the sail - and the honest basis for what it costs.
Zeiloppervlak · Superficie vélicaAspect ratio
The relationship between a sail's height and width: tall and narrow, or low and broad.
Shape & trim
Draft (camber)
The depth of the curve in a sail - how much belly it has.
ZeilbuikDraft position
How far aft the deepest point of the curve sits - and the clearest sign a sail is worn out.
Twist
The sail's upper part opening further than its lower part - usually a good thing.
Twist · TorsiónLuff round
The outward curve cut into the luff, which becomes belly when the sail goes up the mast.
VoorlijkrondingCunningham
A downhaul at the luff that pulls draft forward and flattens the front of the sail.
Outhaul
The control that pulls the clew aft along the boom to flatten the foot.
Boom vang
A tackle from mast base to boom that controls leech tension when the sheet is eased.
Leech line
A small adjustable cord inside the leech, used only to stop flutter.
Telltale
A small yarn or ribbon that shows how air is flowing over the sail.
Verklikker · CatavientosCuts & construction
Cross-cut
Panels running side to side, square to the leech - the classic, economical construction.
Kruissnit · Corte cruzadoRadial cut
Panels fanning out from the loaded corners, following the lines the load actually takes.
Radiaalsnit · Corte radialPanel (gore)
One piece of cloth in the sail. A sail is an assembly of them, not one sheet.
Baan · PañoBroadseam
Tapering a seam so flat cloth becomes a curved wing.
Batten
A stiff strip in a pocket that holds the leech out and stops it flogging.
Zeillat · SableReef points
Reinforced rows used when shortening a mainsail in heavy air.
Rifpunten · RizosBolt rope
A rope sewn into an edge so the sail can feed into a mast, boom or furler groove.
Lijketouw · RelingaLuff attachment
How the luff connects to the mast, stay or furler; the detail that must match the boat.
Cringle
A reinforced eye in a sail for a line, hook or shackle.
Headboard
A plate at the head of a mainsail that spreads halyard load and supports roach.
Cloth
Sails & rigs
Full batten vs semi batten
Battens all the way to the luff, or only in the top of the leech.
Genoa vs jib
Not two objects - one scale. It's about how far the sail overlaps the mast.
Genua / fok · Génova / foqueSpinnaker: symmetric vs asymmetric
The big downwind sail - with a pole and two identical sides, or without one.
Spinnaker · SpinnakerCode sail / gennaker
The sails between a genoa and a spinnaker, named by their mid-girth.
Gennaker · GennakerFour-sided sails: gaff, gunter, lug and sprit
Traditional mainsails with a spar along the head - four corners, not three.
Gaffel, steek, sprietStorm jib
A small, strong headsail for heavy weather, set forward of the mast.
Stormfok · TormentínTrysail
A small heavy-weather mainsail set when the normal main is too large or unsafe.
TrysailFurling
Rolling a sail around a stay, foil, boom or mast so it can be stored or reefed.
No term matches that. Ask us instead - if you had to look it up, the entry is missing and we want to write it.
Why bother
Know six of these words and you’ll get a better sail.
Most of what goes wrong between an owner and a sailmaker is vocabulary. You tell us “the back of it goes baggy”; that could be four different problems with four different prices, and we have to come and look. Say “the draft has moved aft and the leech is hooking” and we can help you over the phone. Missing a word? Tell us and we’ll write it.