Boat hull

Abstract

A boat hull includes a bow section and a flat aft section to allow an air film to be introduced under the boat hull. At least one slot or round hole is arranged proximate a location where the bow section meets the flat aft section. The slot or round hole provides a low-pressure injection point for pumped or drawn-in air and/or exhaust gas, which lubricates an operative surface of the flat aft section.

1 . A boat hull, comprising a bow section and a flat aft section to allow an air film to be introduced under the boat hull, wherein:
 proximate to a location where the bow section meets the flat aft section there is provided at least one slot or round hole which provides a low-pressure injection point for pumped or drawn-in air and/or exhaust gas, for lubrication of an operative surface of the flat aft section.   
     
     
         2 . The boat hull according to  claim 1 , wherein the at least one slot or round hole is rear facing. 
     
     
         3 . The boat hull according to  claim 1 , wherein the at least one slot or round hole is configured to provide a sufficient pressure reduction to excite and maintain a venturi effect. 
     
     
         4 . The boat hull according to  claim 1 , further comprising a pump or blower for distributing the air and/or exhaust gas to the at least one slot or round hole. 
     
     
         5 . The boat hull according to  claim 1 , comprising secondary apertures provided further aft of the said at least one slot or round hole. 
     
     
         6 . The boat hull according to  claim 1 , wherein the air and/or exhaust gas flows from numerous locations ducted from above the floatation waterline. 
     
     
         7 . The boat hull according to  claim 1 , further comprising at least one first pair of generally vertical ribs extending longitudinally along the underside of the hull towards the stern. 
     
     
         8 . The boat hull according to  claim 7 , further comprising a second pair of generally vertical ribs, each rib of the second pair of generally vertical ribs extending downwardly from a corresponding outboard edge of the hull, a depth of the ribs increasing towards the stern. 
     
     
         9 . The boat hull according to  claim 7 , wherein the at least one slot or round hole is provided at a leading edge of a channel formed between adjacent ribs. 
     
     
         10 . The boat hull according to  claim 1 , further comprising a plurality of chines extending downwardly from a bow of the hull towards a stern of the hull, each chine in transverse cross section being substantially straight and substantially horizontal and arranged so that a centreline of each chine lies in a plane which is parallel to a plane extending through a centreline of an adjacent chine, wherein
 between each chine is a generally vertical section,   a central chine sits lower and forward of adjacent chines which are disposed progressively higher and rearward toward sides of the hull, and   an aft portion of a base of the hull is generally flat and each chine terminates at the flat aft portion to provide a generally continuous transition from the chine to the flat base of the hull.   
     
     
         11 . The boat hull according to  claim 1 , further comprising a plurality of chines extending downwardly from a bow of the hull towards a stern of the hull, each chine being, at least at a forward portion thereof, in transverse cross section substantially straight and inclined toward a central longitudinal plane of the hull and arranged so that a centreline of each chine lies in a plane which is parallel to a plane extending through a centreline of an adjacent chine, wherein
 a central chine sits lower and forward of adjacent chines which are disposed progressively higher and rearward toward sides of the hull, and   an aft portion of a base of the hull is generally flat and each chine terminates at the flat aft portion to provide a generally continuous transition from the chine to the flat base of the hull.   
     
     
         12 . The boat hull according to  claim 10 , wherein a vertical separation of the chines varies along a length of the chines to allow the chines to transition from being generally aligned at the bow through greater offset sections at mid bow to merge with a generally flat underbody, and wherein a substantially vertical surface is disposed between adjacent chines. 
     
     
         13 . The boat hull according to  claim 10 , further comprising a channel formed in opposite side walls of the hull at a rearward location, the channels being configured to direct water inwardly from opposite sides of the hull to merge behind the stern. 
     
     
         14 . The boat hull according to  claim 10 , further comprising an internal propulsion system for transferring displaced water from under the hull to a low pressure void formed behind the hull. 
     
     
         15 . The boat hull according to  claim 14 , wherein the internal propulsion system includes an outlet which is adjustable in aperture size to vary a water acceleration point in response to speed changes. 
     
     
         16 . The boat hull according to  claim 14 , wherein the flat aft portion is formed in multiple vertically offset bottom segments and chines which are centrally disposed terminate at a lowermost bottom segment and incorporate an intake for the internal propulsion system. 
     
     
         17 . The boat hull according to  claim 10 , wherein the flat aft portion is formed in multiple vertically offset bottom segments and chines which are centrally disposed terminate in a lowermost bottom segment, and wherein the lowermost bottom segment tapers towards the stern. 
     
     
         18 . The boat hull according to  claim 14 , further including a trim tab extending from a lower rearward portion of the hull. 
     
     
         19 . The boat hull according to  claim 12 , wherein a lower portion of the hull is in the form of a displacement hull into which the chines merge. 
     
     
         20 . A boat, having at least one hull according to  claim 8 .