Cuts & construction
Panel (gore)
One piece of cloth in the sail. A sail is an assembly of them, not one sheet.
DutchBaanour Dutch loft →
SpanishPañoour Spanish loft →
Sailcloth comes off the roll in a fixed width — a couple of metres at most. Every sail bigger than a dinghy's is therefore an assembly of panels seamed together, and how those panels are laid out is the construction: see cross-cut and radial cut.
On a spinnaker the vertical panels are usually called gores. They are not parallel strips: they are tapered wedges, converging as they climb, meeting at a point at the head. That is a consequence of the shape — at the head, luff and leech are the same place — and it is why a spinnaker made of straight strips would be a lie about how kites are built.
You can see it for yourself in our sail designer: the gores you paint are the gores we would cut.