Encyclopedia
Sail terms, explained by the people who cut them.
28 terms, one page each. Every diagram is generated 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 run a Dutch loft and a Spanish one, 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 vélicaShape & 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.
VoorlijkrondingCuts & 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 · SableCloth
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, sprietNo term matches that. Ask us instead — if you had to look it up, the entry is missing and we want to write it.
Phase A
This is the vocabulary. The chapters come next.
Everything here is established sailmaking terminology — the words the whole trade uses, which we can publish on our own authority. The next volume is about how sails are actually built and chosen, and none of that ships until a sailmaker with decades on the floor has read it. Missing a term? Tell us and it goes on the list.