Hydraulic jet propulsion apparatus for water-borne craft

Claim 1

AS A PART OF PROPULSION APPARATUS FOR WATER CRAFT INCLUDING MEANS DEFINING A WATER-CONVEYING CONDUIT HAVING AN INLET END AND A RESTRICTED OUTLET END, A PUMP WITHIN SAID CONDUIT FOR DRAWING WATER INTO THE CONDUIT THROUGH SAID INLET END AND DISCHARGING THE WATER AS A PROPULSION JET THROUGH SAID OUTLET END, A DISCHARGE SECTION DEFINING THE RESTRICTED OUTLET END OF THE CONDUIT AND WHICH SECTION INCLUDES A DISCHARGE NOZZLE AND AN ACCELERATION CHAMBER, THE ACCELERATION CHAMBER BEING ARRANGED BETWEEN THE PUMP AND THE DISCHARGE NOZZLE FOR PROVIDING A PASSAGE MEANS FOR THE FLOW OF WATER FROM THE PUMP TO THE NOZZLE, SAID PASSAGE MEANS BEING PROVIDED WITH AN INLET AND AN OUTLET END AND HAVING A CROSS-SECTION WHICH IS ANNULAR AT SAID INLET AND WHICH MERGES SMOOTHLY ITO A CIRCULAR SECTION OF SMALLER AREA AT SAID OUTLET END, SAID PASSAGE MEANS HAVING A FORWARD PORTION AND AN AFT PORTION, SAID FORWARD PORTION EXTENDING FOR AT LEAST HALF OF THE DISTANCE FROM SAID INLET TO SAID OUTLET END OF THE PASSAGE MEANS AND CONVERGING CONTINUOUSLY FROM SAID INLET TO ITS JUNCTION WITH THE AFT PORTION AND A PLURALITY OF STRAIGHTENING VANES LOCATED WITHIN SAID FORWARD PORTION OF ANNULAR CROSS-SECTION EXTENDING AXIALLY WITHIN SAID FORWARD PORTION FOR SUBSTANTIALLY THE FULL LENGTH THEREOF.