Luff (Sail Edge)

The leading edge of a sail.

On a mainsail it normally runs between tack and head beside the mast; on a headsail it lies along or ahead of the supporting stay or foil. The luff may contain a bolt rope, slides, cars, hanks or a shaped tape according to the attachment system.

Halyard, cunningham and tack tension influence luff shape and draft position. Wrinkles can indicate insufficient tension, but some are intentional or result from cut and load, so adjustment should be based on sail design and conditions rather than the assumption that the luff faces the wind only when correctly set.