Patent ID: 7278366

Claim:
An apparatus for use with a mainsail disposed in a first plane between a mast and a boom, comprising: a boomlet disposed substantially perpendicular to the boom and the mass; a second sail, coupled to the boomlet and disposed longitudinally along the boom in a second plane substantially perpendicular to the first plane and disposed on a leeward and windward side of the mainsail; a pulley, rotatable around an axis parallel to the mast; a first tensioner, affixed to the boomlet distal from the boom and extending from the boomlet through the pulley and to the boom distal from the mast; a second tensioner, affixed to the boomlet distal from the boom and extending from the boomlet to the boom distal from the mast; and wherein the boomlet is rotatably affixed to the boom, permitting boomlet rotation in the second plane.