Fisherman's staysail

A fisherman is a sail placed between the fore and main masts of a sailing ship, usually a schooner but also including brigantines. All four of its sides are typically set flying. The purpose of a fisherman is to catch light winds aloft, as it is a large sail set high on the masts. In some rigs, it overlaps other sails and spars such as the gaff of the foresail and therefore must be fully lowered and re-raised at every tack and jibe.