A fisherman's staysail is a staysail

Staysail

A staysail is a fore-and-aft rigged sail whose luff can be affixed to a stay running forward from a mast to the deck, the bowsprit or to another mast....

 placed between the fore and main masts of a sailing ship, usually a schooner

Schooner

A schooner is a type of sailing vessel characterized by the use of fore-and-aft sails on two or more masts with the forward mast being no taller than the rear masts....

 but also including brigantines

Brigantine

In sailing, a brigantine or hermaphrodite brig is a vessel with two masts, only the forward of which is square rigged.-Origins of the term:...

. 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. Because it normally overlaps other sails and spars

SPARS

SPARS was the United States Coast Guard Women's Reserve, created 23 November 1942 with the signing of Public Law 773 by President Franklin Delano Roosevelt. The name is a contraction of the Coast Guard motto: Semper Paratus and its English translation Always Ready...

 such as the gaff

Gaff rig

Gaff rig is a sailing rig in which the sail is four-cornered, fore-and-aft rigged, controlled at its peak and, usually, its entire head by a spar called the gaff...

 and foresail, it must be fully lowered and re-raised at every tack

Tack (sailing)

Tack is a term used in sailing that has different meanings in different contexts, variously a part of a sail, and an alignment with the wind. When using the latter sense, the maneuver of turning between starboard and port tack is either tacking or jibing....

 and jibe

Jibe

A jibe or gybe is a sailing maneuver where a sailing vessel turns its stern through the wind, such that the wind direction changes from one side of the boat to the other...

.