Gaff rig

Gaff rig is a sailing rig (configuration of sails) in which a sail is a four-cornered fore-and-aft rigged item controlled at its peak and, usually, its entire head by a spar (pole) called the gaff. The gaff enables a fore and aft sail to be four sided, rather than triangular, and as much as doubles the sail area that can be carried by that mast and boom (if a boom is used in the particular rig).
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