Outhaul

A sail control that tensions or positions the clew away from the mast or towards the outboard end of a boom or spar.

On a conventional mainsail the outhaul pulls the clew aft along or towards the boom end, changing foot tension and lower-sail depth. It may be a simple line, an internal purchase, a tackle or a powered system and works with tack position, mast bend and other controls.

Greater tension generally flattens the lower sail and less tension permits more depth, but the response depends on sail cut and whether the foot is loose or retained in the boom. Clew fittings, wire, blocks, purchases and termination points carry substantial load and require inspection.