Lifting device for fully planing or semi-planing watercrafts

Abstract

A lifting device ( 10 ) for watercrafts of the fully planing or semiplaning type provides at least a transversal element ( 15 ) constrained to the bottom ( 25 ) by means of supports orthogonal to the waterline (8) and suitable to increase the hydrodynamic lift acting on the bottom ( 25 ). The position of the device ( 10 ) may be under the barycentre ( 5 ) or slightly shifted from it, and generates, when in navigation at a sufficient speed ( 4 ), an additional hydrodynamic lift (6), which adds to the hydrodynamic lift ( 3 ) on the bottom and to the hydrostatic lift ( 2 ) for balancing the weight of the watercraft. The transversal element ( 15 ) is arranged substantially parallel to the watercraft bottom ( 25 ), so that in fully planing or semi-planing conditions it is inclined with respect to the speed ( 4 ) of the watercraft. This way it is possible to reduce the amount of water displaced during navigation and to supply a steady hydrodynamic lift.

1 . Lifting device for watercrafts, in particular of the type with fully planing or semi-planing bottom, characterised in that it provides at least a transversal element constrained to the watercraft at a predetermined distance from the bottom and suitable to increase the hydrodynamic lift on said bottom.  
   
   
       2 . Device, according to  claim 1 , wherein said transversal element in use has an upper surface that faces the bottom and a lower surface opposite to the upper surface, said transversal element being subject to a lifting force perpendicular to the lower surface owing to the difference of pressure between the two surfaces when it is located in a flow.  
   
   
       3 . Device, according to  claim 1 , wherein said or each transversal element is arranged substantially parallel or slightly inclined with respect to the bottom.  
   
   
       4 . Device, according to claims  2  or  3 , wherein means are provided for adjusting the inclination of at least one part of the surface of said or each transversal element with respect to the bottom.  
   
   
       5 . Device, according to  claim 1 , wherein said or each transversal element is arranged below the bottom at the barycentre of the watercraft.  
   
   
       6 . Device, according to  claim 1 , wherein said or each transversal element is arranged below the bottom shifted with respect to the barycentre of the watercraft for giving a trimming correction to the watercraft.  
   
   
       7 . Device, according to  claim 1 , wherein said or each transversal element is constrained below the bottom of the watercraft by at least a support element substantially orthogonal to the waterline.  
   
   
       8 . Device, according to  claim 9 , wherein said or each support element is a shaped plate with an opening, said plate being arranged substantially orthogonal to the waterline.  
   
   
       9 . Device, according to  claim 1 , wherein said transversal element is made of a substantially V-shaped single part arranged transversally to the bottom of the watercraft, said single shaped part being arranged substantially transversal to the bottom of the watercraft for substantially all its width and more.  
   
   
       10 . Device, according to  claim 1 , where at least a first and a second transversal element are provided fixed in different points of said bottom symmetrically to its longitudinal midplane.  
   
   
       11 . Device, according to  claim 1 , where at least a first and a second transversal element arranged are provided with the respective surfaces substantially parallel.  
   
   
       12 . Bottom for watercrafts in particular of the fully planing or semi-planing type, characterised in that of having at least one lifting device according to the previous claims.