Abstract: This patent describes a method for steering an unmanned surface vessel consisting of a hull, keel, and non-self-tacking rigid wing sail. Unlike conventional vessels, it doesn't require a rudder. Steering is achieved by rotating the wing sail around a vertical axis using an actuator. The center of lateral resistance is spaced aft of the center of windage, balancing the vessel to the wind. The vessel maintains various angles relative to the wind and holds a port or starboard tack without active steering. The sail position only needs changing when a new course is desired. The vessel can progress at all angles to the wind, whether by a zigzagging course or a straight line. This method eliminates the need for an active rudder to maintain course, reducing power consumption and component wear.

Abstract: A trimaran which includes a self-righting structure positioned near the stern that substantially raises the center of buoyancy. The trimarans two peripheral hulls are shorter than the main hull and positioned near the one end to create an unstable inverted environment wherein when inverted the vessel rests primarily on the self-righting structure and an end of the main hull, substantially raising the center of gravity and creating an unstable configuration. This causes a pitch or roll about the vessel's longitudinal axis, which continues until the vessel has returned to its more stable upright position resting on three hulls.

Abstract: A trimaran which includes a self-righting structure positioned near the stern that substantially raises the center of buoyancy. The trimarans two peripheral hulls are shorter than the main hull and positioned near the one end to create an unstable inverted environment wherein when inverted the vessel rests primarily on the self-righting structure and an end of the main hull, substantially raising the center of gravity and creating an unstable configuration. This causes a pitch or roll about the vessel's longitudinal axis, which continues until the vessel has returned to its more stable upright position resting on three hulls.