Tractor Mode Marine Propulsion

Abstract

A drive for a marine vessel may include a fully wetted propeller with a fixed drive shaft configuring the propeller in a tractor mode wherein the propeller pulls the water rearwardly relative to a bow of the marine vessel when traveling in a forward direction. The propeller is preferably mounted in a range of 10% to 60% of a length of the marine vessel toward the how from a transom and operates cavitation-free.

What is claimed is: 
     
         1 . A marine vessel comprising:
 a hull including a bottom with at least one tunnel configured to accept a drive;   wherein the drive includes a fixed shaft and a tractor mode configured propeller mounted at least partially within the tunnel and configured to rotate such that a thrust is created pulling the marine vessel in a forward direction.   
     
     
         2 . The marine vessel of  claim 1 , wherein the fixed shaft is joined to the propeller with a shaft angle of between 3-12 degrees to a horizontal plane when the marine vessel is stationary in the water, and producing an effective shaft angle of about 0 degrees when the marine vessel is in motion at a cruising running angle of attack. 
     
     
         3 . The marine vessel of  claim 2 , wherein the shaft angle is about 6 degrees or less to the horizontal plane. 
     
     
         4 . The marine vessel of  claim 1 , wherein the fixed shaft includes a positive shaft angle producing a lift in a bow region of the marine vessel when moving at cruising speed. 
     
     
         5 . The marine vessel of  claim 1 , wherein the propeller is fully submerged in water and does not produce a vapor cavity when powering the marine vessel at a speed greater than 20 knots. 
     
     
         6 . The marine vessel of  claim 5 , wherein the speed is greater than 50 knots. 
     
     
         7 . The marine vessel of  claim 1 , wherein the propeller includes efficiency ratios of over 60%. 
     
     
         8 . The marine vessel of  claim 1 , wherein the propeller includes a completely clean inflow condition. 
     
     
         9 . The marine vessel of  claim 1 , wherein the propeller includes an overall propulsive coefficient of over 50% 
     
     
         10 . The marine vessel of  claim 1 , further comprising an interceptor on a trailing edge of the tunnel providing the bow of the marine vessel with an adjustable positive and a negative lift when moving at cruising speed. 
     
     
         11 . The marine vessel of  claim 1 , wherein when cruising at a speed greater than 20 knots, the marine vessel does not produce a roostertail. 
     
     
         12 . The marine vessel of  claim 1 , further comprising a power source within the hull of the marine vessel mounted rearward of the propeller. 
     
     
         13 . A drive for a marine vessel comprising:
 a fully wetted propeller when the marine vessel is floating in water;   a fixed drive shaft configuring the propeller in a tractor mode wherein the propeller pulls the water rearwardly relative to a bow of the marine vessel when traveling in a forward direction; and wherein   the propeller is mounted in a range of 10%-60% of a length of the marine vessel toward the bow from a transom.   
     
     
         14 . The drive for a marine vessel of  claim 13 , further comprising a tunnel in a bottom of the hull, wherein at least a portion of the propeller is mounted within the tunnel. 
     
     
         15 . The drive for a marine vessel of  claim 13 , wherein the propeller includes a diameter in the range of about 50% to 90% of a diameter of the tunnel. 
     
     
         16 . The drive for a marine vessel of  claim 13 , wherein the propeller rotates to produce a thrust disc such that both an upper half and a lower half of the propeller produce the thrust. 
     
     
         17 . The drive for a marine vessel of  claim 13 , wherein the propeller:
 produces an effective shaft angle of 0 degrees when the marine vessel is in motion at a cruising running angle of attack; and   does not produce cavitation during operation powering the marine vessel at a speed greater than 20 knots.   
     
     
         18 . The drive for a marine vessel of  claim 17 , wherein the speed is greater than 50 knots. 
     
     
         19 . The drive for a marine vessel of  claim 13 , further comprising:
 a v-drive unit within a hull of the marine vessel; and wherein   the drive shaft is substantially fully enclosed within the hull of the marine vessel.   
     
     
         20 . The drive for a marine vessel of  claim 13 , further comprising:
 an interceptor on a trailing edge of the tunnel providing the bow of the marine vessel with an adjustable positive and a negative lift when moving at cruising speed; and   wherein the propeller does not produce a rooster tail when the marine vessel is cruising at a speed greater than 20 knots.   
     
     
         21 . The drive for a marine vessel of  claim 13 , further comprising:
 a power source within a hull of the marine vessel and rearward of the propeller; or any position desired in the hull and   a v-drive unit within the hull of the marine vessel; and wherein   the fixed drive shaft is fully enclosed within the hull of the marine vessel.   
     
     
         22 . The drive for a marine vessel of  claim 13 , wherein the propeller includes:
 efficiency ratios of over 60%; and   an overall propulsive coefficient of over 50%.