Abstract: A rudder for a water craft is constructed to automatically compensate for impact on the rudder while the craft is maneuvering. The lower portion of the rudder is mounted to an upper portion by a pin. The lower portion can pivot about the pin to reduce drag and draft. The lower portion is spring loaded to return to the original position after impact.

Abstract: A rudder for a water craft is constructed to automatically compensate for impact on the rudder while the craft is maneuvering. The lower portion of the rudder is mounted to an upper portion by a pin. The lower portion can pivot about the pin to reduce drag and draft. The lower portion is spring loaded to return to the original position after impact.

Abstract: An improved method for raising a propeller up into the hull of a marine water craft for the purpose of reducing the likelihood of underwater impact and improving shallow water operation without encountering the high efficiency losses normally associated with shallow draft drive systems or water jets. It utilizes a unique tunnel which is open bottomed and extends longitudinally in the running surface of the hull. The lead in to the tunnel, which is termed the “chute” forms the entry to a deeper portion of the tunnel located further aft. A super-cavitating propeller is positioned in the aft tunnel section. The propeller is raised vertically into the tunnel such that the propeller blade tips can be above, below or flush with the running surface of the hull but the prop shaft is always above the running surface of the hull. The invention relates to the longitudinal position of the chute with respect to the propeller, the general shape of the chute and its normal method of operation.

Abstract: The instant invention is directed toward a marine craft having a semi-enclosed surfacing type propeller in a tunnel that draws air through specific areas located and shaped to enhance performance and compensate for prime mover torque and horsepower characteristics. The invention further relates to the field of marine water craft, particularly to high speed power boats utilizing a surface piercing propeller drive system mounted within a propeller tunnel formed integral to the hull of the boat, and most particularly to inclusion, within a wall of said tunnel, of a means for providing air thereto; said means being judiciously placed for linearization of the relationship between vessel velocity and engine speed.

Abstract: The instant invention is directed toward a marine craft having a semi-enclosed surfacing type propeller in a tunnel that draws air through the specific areas located and shaped to enhance performance and compensate for prime mover torque and horsepower characteristics. The invention consists of these air induction features with description of their relationship to craft performance and operating characteristics. This invention also relates certain structures and configuration of these elements, as to enhanced control of said marine craft. The control of these elements having no moving parts or operator interface. Its sequencing is established by the hull movement and the water around it.

Abstract: A marine craft having a propeller tunnel in which the sidewalls of the tunnel are essentially parallel and vertical and mate with a descending upper surface of the tunnel which optionally can be divided into a transom plate portion, engine plate portion, and bottom plate portion. The bottom plate portion mates with the bottom of the boat hull in a sharp line intersection. A surfacing propeller and associated drive shaft is mounted in the tunnel with a rudder positioned aft of the surfacing propeller. Baffles are provided on the lateral sides of the tunnel and terminate in a forward portion aft of the bottom plate portion of the tunnel. Optionally the exhaust can be vented onto the bottom plate portion of the tunnel to augment the flow of air.