Marine pump-jet propulsion system

A marine propelling device to facilitate ahead-and-astern propulsion comprising a reversible hydraulic-jet ejector structure extending longitudinally within the hull of a marine vessel and disposed below the normal waterline;

• said reversible ejector structure being bounded by sidewalls of a longitudinal open-channel conduit formed by downwardly depending chines or keels from the hull structure of said marine vessel;
• oppositely-directed thrust-augmenting secondary-nozzle ejector stagings centrally disposed in said open channel conduit to discharge towards their respective adjacent propelling end of said ejector structure;
• each ejector staging having a ducted axial pump disposed within said open-channel conduit to supply high-velocity motive fluids into the central bore of at least one adjacent secondary-nozzle member;
• the inlet casing of each ducted axial pump being disposed to admit pump suction fluids from the direction of positive differential pressure when underway and the outlet casing of each ducted axial pump being disposed to discharge high-velocity motive fluids therefrom.