Abstract: A modified boat hull, providing for dual, non-ventilating aft thruster tunnels. Each tunnel includes a generally tubular section which fluidly communicates with the transom outlet orifice, and a converging transition section which communicates at the extreme opposite end with a water inlet orifice which is positioned within an enhanced, vertical strake surface. The vertical strake surface is located beneath the chine of the boat, as well as beneath the water line. The modified hull also includes an inboard offset for the vertical strake surface, and a chine step to enhance hydrodynamic performance of the hull when attempting to achieve or exceed plane speed.

Abstract: A spill resistant fuel cap and ventilation system to prevent fuel from spilling during the boat refueling process and when internal fuel system pressure increases, and for maintaining the internal pressure of the fuel system at a predetermined level, wherein the system comprises a fuel fill neck fluidly connected to a tank, the fuel fill neck having two venting apertures defined by it with one venting aperture in fluid communication with the tank and the other aperture in fluid communication with an air intake vent, such that the system provides two vapor and air venting paths for removing vapor and air during refueling and for relieving pressure, respectively, and such that an air intake venting path is formed for inducing air into the system through the fuel fill neck to prevent pulling vacuum in the tank during boat engine operation.

Abstract: An improved marine engine exhaust system for discharging engine exhaust above the water line when at idle or low speeds, and below the surface of the water at high speed in a submerged turbulent region generated by a hydrodynamic fitting fixed to a the undersurface of the vessel hull, wherein the gas is maintained for a period of time, until the low pressure area following the vessel has passed.