Marine propulsion device with engine heat recovery system and streamlining hull closures

Claim 1

In a boat propelled directionally by an inboard marine water jet propulsion system for boats supported by the boyant property of water when said jet is operating, said boat comprising: (a) A boat; (b) A motor located therein; (c) A water pumping means coupled operably to said motor; (d) Said water pumping means afixed to said boat to allow the drawing of fluid (100) from the outside of the boat and through an intake region (26) into the jet pump and (e) By the operation of said pumping means the water is discharged through a defined pathway to allow the expression of said drawn fluid through a nozzle to the outside of said boat where the result of said expression of the fluid through the nozzle is the propulsive reaction of the boats travel apposed to the direction of said fluid expression; wherein the improvement is comprising: (1) Said nozzle means being operably connected by a thrust transmission tube means (38) to a pumping means (18) including an impeller casing for housing a water impelling means (28) therein; (2) Said water impelling means pumping water (100) at a rate sufficient to induce turbulent flow of the water when it is pumped in a passageway (34); (3) Said passageway (34) including means for heating its interior surface to a temperature above that of the water (100) being drawn in by said pumping means (18), said means for heating being in thermal communication with said impeller casing; (4) Wherein the energy lost by a driving motor operatively connected to said pump in transporting a water stream through said pump is reduced by the effect of increasing the boundry layer water temperature, thus lowering the pressure change necessary to draw gas out of solution adjacent to said boundry when said water is in a turbulent flow condition.