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US 4,091,761 AGranted
Modified tunnel hull boat
OwnerAllan J. Fehninventor
Life of this patent
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OwnerAllan J. Fehninventor
Estimating the term…
A modified tunnel hull boat in which there are two downwardly extending sponsons defining a tunnel between their inner walls, the boat having a center rib projecting downwardly from the bottom of the boat into the tunnel and having a lower wall which acts as a planing surface. The distance between the inner walls of the sponsons and the outer walls of the center rib decreases from the bow to an area adjacent the midpoint of the boat fore and aft and then increases abruptly after this point so as to create a venturi throat. The reduced pressure adjacent the venturi throat tends to minimize the effect of head or tail winds upon the attitude of the boat. The amount of lift on the rearward portion of the boat is also increased so that the bow does not rise as much at high speeds. The introduction of air into the tunnel is increased by the provision of two flat portions adjacent the bow which are directed upwardly in a forward direction so as to act as scoops to direct air into the tunnel to increase the lifting effect. Curved strakes of relatively short length are provided adjacent the bow to give additional lift to the bow at low speeds.
A modified tunnel hull boat having two sponsons extending downwardly and having facing inner walls which extend generally vertically to define with the bottom a tunnel, said sponsons each having outer walls that approach the inner walls as they extend downwardly so that the lowermost portion of each sponson is very narrow to provide little planing effect, a center rib projecting downwardly from the bottom of the boat into said tunnel and having a relatively wide lower wall which acts as a planing surface, the distance between the inner walls of said sponsons and the outer walls of said center rib decreasing from the bow to an area closely adjacent the midpoint of the boat fore and aft and then increasing abruptly thereafter so as to create a venturi throat adjacent the midpoint of the boat fore and aft so that the reduced pressure adjacent the venturi throat tends to minimize the effect of head or tail winds upon the attitude of the boat.
Dependencies are inferred from the claim text.