Centrifugal marine propeller

Claim 1

A centrifugal propeller assembly comprising: a plurality of substantially identical blades, each of said blades having a root end and a leading edge spiraled rearwardly to the trailing end, a hub attached to the root ends of the blades, and a shell fixed to the tips of the blades, the shell being generally spheroidal and tapering from a small inlet end forward to a large outlet end rearward, the shell being arcuately concave, the annulus defined by the shell being of one width at points adjacent the forward edges of the blades and being substantially narrower than said one width at points adjacent the trailing edges of the blades, the bladeS increasing in width from the hub to the central portions of the blades proceeding radially outwardly from the hub, the outer tip end portions of the blades continuously curving radially outwardly to merge smoothly into the shell, the forward edge of the shell forming continuations of the forward edges of the blades, the forward edge of the shell curves in large radii forwardly and radially outwardly from the forward edges of the blades and the forward edge of the shell at any point never being forward of the adjacent portion of the blades, each trailing edge of the blades being generally S-shaped with the portion of the trailing edge between the hub and the central portion thereof being concave and the portion of the trailing edge between the shell and the central portion thereof being convex.