Propulsion unit for multihull such as a catamaran

Abstract

The invention concerns a propulsion unit for a multihull such as a catamaran, comprising at least one turbine, seawater suction means and seawater backflow means. The invention is characterized in that said device comprises a seawater turbine directly driven by a motor inside each of the hulls ( 1 ), the seawater suction means being positioned at the front, outside each hull ( 1 ) in an overpressure zone generated by the bow wave and the seawater backflow means being positioned inside each hull ( 11 ), on the rear of the boat pitch pivot pin, said backflow means having an outlet ( 5 ) capable of being pivoted and emerging inside the channel defined between two hulls ( 1 ).

1 . Propulsion unit for multihulls such as a catamaran, having at least one turbine, seawater suction means and seawater backflow means, characterized in that the propulsion unit comprises a seawater turbine directly driven by an engine in each of the hulls, seawater suction means positioned in front preferably outside each hull in an overpressure zone generated by the bow wave and seawater backflow means positioned in the rear inside each hull, on the back of a pitch pivot pin of the multihull, said backflow means having an outlet capable of pivoting and emerging inside a channel defined between two hulls. 
   
   
       2 . Unit according to  claim 1 , characterized in that the suction means are positioned in front outside each hull in an overpressure zone linked to the bow wave affording the turbines natural supercharging. 
   
   
       3 . Unit according to  claim 1 , characterized in that the seawater backflow means comprise at least one pivoting elbowed nozzle consisting of a first tube, in which a second tube is pivoted, of diameter slightly less than that of the first tube, a reduction cone enabling the pressure of the water jet at one end of the inner tube and an elbow or outlet nozzle welded to the cone on the small diameter side. 
   
   
       4 . Unit according to  claim 3 , characterized in that the difference in diameter between the tubes is compensated by sleeving of the inner tube pivoting by means of a material compatible with the seawater, housings being cut into the sleeving to receive the O-ring seals ensuring tightness between the tubes. 
   
   
       5 . Unit according to  claim 3 , characterized in that the outer tube can be fastened inside the hull opposite an opening machined in said hull, while the inner tube can be engaged outside the hull in the tube across the opening machined in the hull, and a locking plate can be engaged on the outlet nozzle and fastened on the outside of the hull. 
   
   
       6 . Unit according to  claim 3 , characterized in that an outlet nozzle or elbow can be rotated between two outlet positions of the water jet downward or upward, in which no propulsive force is produced, the outlet positions of the water jet of the front and rear motions being at 90° from either vertical position. 
   
   
       7 . Unit according to  claim 5 , characterized in that the locking plate has a circular sector intended to block the opening of the outlet nozzle at least partially, when the outlet nozzle is rotated to an intermediate position at 45° from either of the vertical positions of said outlet nozzle. 
   
   
       8 . Unit according to  claim 6 , characterized in that an intermediate position of an outlet nozzle at 45° from either of the vertical positions of said outlet nozzle places the openings existing in each of the tubes opposite one another, the backflow jets being directed to pipes in front and in back, one ending in a nozzle situated at the rudder post and the other in a pivoting nozzle situated under the third bow. 
   
   
       9 . Unit according to  claim 8 , characterized in that spherical valves are mounted on the pipes in front and in back in order to quickly fill trimming tanks, one situated in front and the other in back in the space between hulls. 
   
   
       10 . Unit according to  claim 9 , characterized in that spherical valves are mounted on the pipes in front and in back in order to quickly fill tanks formed by the walls of the hulls lined inside the boat by a tight bulkhead going from the upper deck to the water line. 
   
   
       11 . Unit according to  claim 1 , characterized in that it further contains additional means of propulsion, consisting of a motor pump provided in each hull in back of the motors of said unit, also usable as a fire pump, while the boat remaining maneuverable.