Abstract: Water directing apparatus for the jet pump inlet of a watercraft having a planing surface within which the inlet is formed. The apparatus is carried by the planing surface and includes a pair of laterally spaced apart, longitudinally extending side fins projecting downwardly of the planing surface. Curvilinear, transversely disposed upstream and downstream vanes are oriented to direct water into the inlet, the angles of attack of the vanes being established to direct boundary layer water into the inlet without separation. The vane combination achieves water flow directional change with minimum drag and flow separation. An embodiment is disclosed employing a vane movable in response to inlet passage pressure.

Abstract: A reversible hydrojet boat drive for the substantially nonturbulent nozzling of water during the forward mode, and effective non jamming seal function during the reverse mode, and comprised of an exact nozzle continuation of the exit passage of the pump, particularly the top wall thereof, and the compatible eccentric relation of the surrounding seals of the reverse gate centered below the axis of gate rotation, thereby to avoid jamming and to eleviate strain on the control system therefor.

Abstract: A noise suppressor for internal combustion engine exhaust, adapted for marine use wherein water coolant is discharged into the chamber of a single-walled riser and partially vaporized by the exhaust gases directed into the dome thereof for downward redirection and discharge from the lower portion of the riser chamber through a muffler element, and preferably through the hull chest and/or cover of a jet pump drive acting as the final noise barrier to atmosphere.