Watercraft hull having a constant flow tunnel and corresponding method

Abstract

A watercraft hull includes an opening in the body of the watercraft for defining a platform slot adjacent the stern. A flow tunnel is disposed within a lower hull portion and extends generally along the length of the lower hull portion to adjacent the platform slot. The ratio of the depth of the flow tunnel to the length of the flow tunnel is sufficiently small to permit the watercraft to remain buoyant in relatively shallow water. A directional keel extends along sides of the flow tunnel and outwardly from the lower hull portion for providing directional control to the watercraft.

1 . A watercraft hull having a constant flow tunnel, the watercraft comprising a bow, stern, lower hull, upper surface, the watercraft hull comprising: 
 an opening in the body of the watercraft defining a platform slot aligned with the watercraft longitudinal axis from a first end to a second end adjacent the stern, and extending transverse to the watercraft longitudinal axis from the lower hull to the upper surface;    a constant flow tunnel disposed within the lower hull having a first side, a second side, a first end and a second end adjacent the first end of the platform slot, the length of the tunnel between the first and second end being substantially equal to the length of the lower hull along the watercraft longitudinal axis; and the depth of the tunnel at the second end being substantially less than the length of the tunnel.    
   
   
       2 . The constant flow tunnel according to  claim 1 , wherein the ratio of the depth of the tunnel to the length of the tunnel is sufficiently small to permit the watercraft to remain buoyant in relatively shallow water.  
   
   
       3 . The constant flow tunnel according to  claim 2 , wherein the watercraft remains buoyant at a depth of less than one foot of water.  
   
   
       4 . The constant flow tunnel according to  claim 2 , wherein the watercraft remains buoyant at a depth of less than six inches of water.  
   
   
       5 . The constant flow tunnel according to  claim 1 , wherein the ratio of the tunnel depth to length varies between 0.01 and 0.1.  
   
   
       6 . The constant flow tunnel according to  claim 1 , wherein the ratio of the tunnel depth to length varies between 0.01 and 0.05.  
   
   
       7 . The constant flow tunnel according to  claim 1 , wherein tunnel features negligible diversion from the first end to the second end.  
   
   
       8 . The constant flow tunnel according to  claim 1  further comprising a directional keel extending along the first and second sides of the tunnel and outwardly from the lower hull for providing directional control to the watercraft.  
   
   
       9 . The constant flow tunnel according to  claim 1 , wherein the slope of the tunnel from the first end to the second end approaches the constant rising slope of water upon exiting from beneath the hull and beyond the stern.  
   
   
       10 . The constant flow tunnel according to  claim 9 , wherein the constant rising slope of water upon exiting from beneath the hull and beyond the stern varies between 1-2 inches per foot.  
   
   
       11 . A constant flow tunnel propulsion system in a watercraft hull, the watercraft comprising a bow, stern, lower hull, upper surface, and an engine having a propeller for propelling the watercraft, the constant flow tunnel propulsion system comprising: 
 an opening in the body of the watercraft defining a platform slot aligned with the watercraft longitudinal axis from a first end to a second end adjacent the stern, and extending transverse to the watercraft longitudinal axis from the lower hull to the upper surface;    a tunnel disposed within the lower hull having a first side, a second side, a first end and a second end adjacent the first end of the platform slot; the length of the tunnel between the first and second end substantially equal to the length of the lower hull along the watercraft longitudinal axis; the depth of the tunnel at the second end substantially less than the length of the tunnel; and    an adjustable platform positioned within the platform slot for supporting the watercraft engine, the adjustable platform having an adjustable height.    
   
   
       12 . The constant flow tunnel propulsion system according to  claim 11 , wherein the ratio of the depth of the tunnel to the length of the tunnel being sufficiently small to permit the watercraft to remain buoyant in relatively shallow water.  
   
   
       13 . The constant flow tunnel propulsion system according to  claim 12 , wherein the watercraft remains buoyant at a depth of less than one foot of water.  
   
   
       14 . The constant flow tunnel propulsion system according to  claim 12 , wherein the watercraft remains buoyant at a depth of less than six inches of water.  
   
   
       15 . The constant flow tunnel propulsion system according to  claim 11 , wherein the ratio of the tunnel depth to length varies between 0.01 and 0.1.  
   
   
       16 . The constant flow tunnel propulsion system according to  claim 11 , wherein the ratio of the tunnel depth to length varies between 0.01 and 0.05.  
   
   
       17 . The constant flow tunnel propulsion system according to  claim 11  further comprising a directional keel extending along the first and second sides of the tunnel and outwardly from the lower hull for providing directional control to the watercraft.  
   
   
       18 . The constant flow tunnel propulsion system according to  claim 17  wherein the directional keel extends along the first and second sides of the tunnel from the first end to within a buffer distance of the second end, the buffer distance substantially less than the length of the tunnel.  
   
   
       19 . The constant flow tunnel propulsion system according to  claim 10 , wherein the slope of the tunnel from the first end to the second end approaches the constant rising slope of water upon exiting from beneath the hull and beyond the stern.  
   
   
       20 . The constant flow tunnel propulsion system according to  claim 19 , wherein the constant rising slope of water upon exiting from beneath the hull and beyond the stern varies between 1-2 inches per foot.  
   
   
       21 . The constant flow tunnel propulsion system according to  claim 10 , wherein the engine propeller and adjustable platform height are commonly adjusted.  
   
   
       22 . The constant flow tunnel propulsion system according to  claim 21 , wherein the engine propeller is adjusted such that the tunnel deflects water into the propeller and away from the mid-section of the engine.  
   
   
       23 . The constant flow tunnel propulsion system according to  claim 21 , wherein the engine propeller and adjustable platform height may be commonly adjusted by one of an electronic and hydraulic means.  
   
   
       24 . The constant flow tunnel propulsion system according to  claim 21 , wherein the adjustable platform comprises a plate aligned with the engine main axis platform slot.  
   
   
       25 . A method for making a constant flow tunnel propulsion system in a watercraft hull, the watercraft comprising a bow, stern, lower hull, upper surface, and an engine having a propeller for propelling the watercraft, the method comprising: 
 forming an opening in the body of the watercraft defining a platform slot aligned with the watercraft longitudinal axis from a first end to a second end adjacent the stern, and extending transverse to the watercraft longitudinal axis from the lower hull to the upper surface;    forming a tunnel disposed within the lower hull having a first side, a second side, a first end and a second end adjacent the first end of the platform slot; the length of the tunnel between the first and second end substantially equal to the length of the lower hull along the watercraft longitudinal axis; the depth of the tunnel at the second end substantially less than the length of the tunnel; and    forming an adjustable platform positioned within the platform slot for supporting the watercraft engine, the adjustable platform having an adjustable height.    
   
   
       26 . The method according to  claim 25 , wherein the ratio of the depth of the tunnel to the length of the tunnel being sufficiently small to permit the watercraft to remain buoyant in relatively shallow water.  
   
   
       27 . The method according to  claim 26 , wherein the watercraft remains buoyant at a depth of less than four inches of water.  
   
   
       28 . The method according to  claim 25 , wherein the ratio of the tunnel depth to length varies between C and D.  
   
   
       29 . The method according to  claim 25 , further comprising the step of forming a directional keel extending along the first and second sides of the tunnel and outwardly from the lower hull for providing directional control to the watercraft.  
   
   
       30 . The method according to  claim 25 , wherein the engine propeller and adjustable platform height are commonly adjusted.