Abstract: A Roller-furling sail both main sail and head sail, such as jibs or genoas, are constructed in the reverse miter cut or Scotch cut. The sails are constructed of sail cloth panels to the luff with one mitered seam bisecting the angle made by the panels that run parallel to the foot and the leech of the sail. The panels running adjacent to the foot and the leech are of a heavier weight cloth than the remaining body of the sail. As the sail is furled a greater portion of the lighter weight sail cloth is taken up thereby leaving an increased percentage of the heavier sail cloth exposed to the stronger winds. The sail may also be provided with a luff flattening panel that is seared to the luff of the sail in a generally curved shape from the area of the tack to the area of the head of the sail. The luff flattening panel allows the sail to be partially furled and maintain the desired flat shape.