Cuts & construction
Bolt rope
A rope sewn into an edge so the sail can feed into a mast, boom or furler groove.
DutchLijketouwour Dutch loft →
SpanishRelingaour Spanish loft →
A bolt rope is a rope sewn into the edge of a sail so that edge can slide into a groove. On a mainsail it may run up the luff, along the foot, or both. On some headsails it forms the luff tape that feeds into a foil or furler.
The rope is not just a convenience. It is part of how the edge is held straight and how load is carried into the spar or stay. Its diameter matters: too small and the sail can pull out or rattle; too large and it will not feed.
Older mainsails sometimes shrink around the bolt rope as the rope and cloth age differently. The sail then appears tight in the luff, develops wrinkles, and refuses to stretch to its designed shape. That is a repair problem, not a trimming mystery.