AMYA Star 45 Class Rules, 2006, Rudder
6.1 Rudders may be constructed of wood, fiberglass, plastic, plastic laminates or metal. The exact shape is not specified, but they may not exceed 4 1/2 inches at the hull (fore and aft) 3 inches at the bottom, (fore and aft); and may not project more than 7 inches below the hull when measured at the post..