Donald W. Hankley - Virginia Beach VA
The United States of America as represented by the Secretary of the Navy - Washington DC
A full or partial tunnel wedge is positioned in the propeller shaft tunnel ft of the propeller on a waterborne craft. The size and angle of the wedge is determined by the characteristics of the particular craft. The wedge converges water flow and increases water pressure aft of the propeller. The higher water pressure increases the propeller thrust and reduces the hull drag of the propeller shaft tunnel thus reducing the shaft horsepower required to maintain a given speed.