Bow lifting body with deadrise

Abstract

A watercraft has a lifting body secured to its bow below the waterline; the lifting body has deadrise on either side of the bow.

1 . A watercraft comprising a hull, including a bow having an outer surface, and a lifting body attached to said bow below the static waterline of the hull; said hull having a fore and aft longitudinal axis, and said lifting body extending laterally away from the outer surface of the bow and from said longitudinal axis; said lifting body being buoyant and having a first lifting body portion adjacent to the bow and extending away from the adjacent outer surface of the bow and at least a second lifting body portion extending laterally outwardly from each side of the first lifting body portion, said second lifting body portions having dead rise with respect to said first lifting body portion on either side of the bow of the hull, whereby said lifting body provides buoyant lift at the bow, hydrodynamic lift at operational speeds and reduction of vertical acceleration in bow movements. 
   
   
       2 . A watercraft as defined in  claim 1  wherein said deadrise is positive. 
   
   
       3 . A watercraft as defined in  claim 1  wherein said deadrise is negative. 
   
   
       4 . (canceled) 
   
   
       5 . (canceled) 
   
   
       6 . (canceled) 
   
   
       7 . A watercraft as defined in  claim 1  wherein said lifting body is mounted directly on the bow of the hull and produces a surface wave train as a result of its shape, its proximity to the free surface of the water and its displacement lift. 
   
   
       8 . A watercraft as defined in  claim 1  wherein the second lifting body portions of the lifting body taper towards the lateral edges of the lifting body. 
   
   
       9 . A watercraft as defined in any one of  claims 1  to  3 ,  7  and  8  wherein said first lifting body portion is thicker than said second lifting body portion. 
   
   
       10 . A watercraft as defined in any one of  claims 1  to  3 ,  7  and  8  wherein the lifting body has a thickness to length ratio of between 10 to 33%. 
   
   
       11 . A watercraft hull as defined in any of  claims 1  to  3 ,  7  and  8  wherein said first and second lifting body portions have longitudinal cross-sections extending parallel to the longitudinal axis of the hull with each such cross-section including symmetrically cambered and generally parabolically shaped cross-sectional portions. 
   
   
       12 . A watercraft hull as defined in  claim 11  wherein the cross-sections of said first lifting body portion adjacent the bow has the maximum thickness of the lifting body and the cross-section of the second lifting body portions being smaller than those of said first section. 
   
   
       13 . A watercraft as defined in  claim 10  wherein the lifting body has a thickness to length ratio of between 10 to 33%. 
   
   
       14 . A watercraft hull as defined in any of  claims 1  to  3 ,  7  and  8  wherein said lifting body has a leading edge portion which conforms, when viewed in plan, to a parabolic form. 
   
   
       15 . A watercraft as defined in any one of  claims 1  to  3 ,  7  and  8  including winglets on the outer edges of said lifting body. 
   
   
       16 . A watercraft as defined in  claim 12  including winglets on the outer edges of said lifting body. 
   
   
       17 . A watercraft as defined in  claim 13  including winglets on the outer edges of said lifting body.