Apparatus for propelling fluid, especially for propulsion of a floating vehicle

A propeller supported on a floating body so as to be completely submerged in water and rotatable about a longitudinal axis of rotation for propelling the floating body in said water, said propeller comprising:

• a shaft rotatably supported on the floating body, said shaft having a forward front end and a rearward back end, and said shaft being driven so as to rotate about the longitudinal axis;
• and
• three propulsion structures supported on and extending in a generally spiral path about said shaft and rotationally staggered with respect to one another;
• each of said propulsion structures having a fluid contact surface with a surface width measured along the fluid contact surface from a radially inward end portion to a outward edge portion;
• said fluid contact surface having a forward engaging portion, an intermediate fluid entraining portion, and a rearward exhaust portion;
• the surface width of the fluid contact surface increasing from the engaging portion to the intermediate fluid entraining portion, and decreasing from the intermediate fluid entraining portion to the exhaust portion;
• the fluid contact surface in the intermediate fluid entraining portion being concave and inwardly and rearwardly disposed so as to radially inwardly enclose a spiral fluid flow volume, with said fluid contact surface being shaped such that cross-sections thereof in a plane perpendicular to the longitudinal axis extend curvingly rearward a distance at least as great as a radially outward extension distance of the fluid contact surface.

A propeller supported on a floating body in water so as to impel said floating body in a forward direction of movement, said propeller comprising:

• a plurality of winglets supported fixedly with respect to each other so as to rotate together about a longitudinally extending axis of rotation;
• each of said winglets comprising
• a winglet body portion extending generally spirally about said axis of rotation and having a generally forwardly-disposed forward surface and a generally rearwardly-disposed rearward surface, said forward and rearward surfaces meeting in an acute-angle winglet edge that also extends generally spirally about said axis of rotation;
• the rearward surface being concave over at least a longitudinal portion of a longitudinal length of the winglet so as to define a generally rearward facing channel rearward of the winglet body portion such that the rearwardly concave rearward surface has a forwardmost channel surface portion at a forwardmost part of the channel;
• the longitudinal portion including a forward intake portion, a retention portion rearward thereof, and an expelling portion rearward of the retention portion;
• wherein, in the intake portion, the winglet edge is oriented such that, as the propeller is rotated, the winglet edge passes into the water with a conforming flow from the winglet edge over the forward and rearward surfaces, and a portion of the water flows into the channel, and
• wherein, from the intake portion to the retaining portion, the forw-ardmost channel surface portion of the rearward surface and the winglet edge extend continuously obliquely rearward, the winglet edge extending continuously obliquely rearwardly more steeply relative than the forwardmost channel surface portion, and the rearward surface widens and defines the channel to as to be wider in the retaining portion;
• wherein, in the retaining portion, the winglet edge is oriented such that the rearward surface contiguous thereto extends rearward in a direction that differs from the longitudinal direction by no more than the acute angle;
• and
• wherein, in the expelling portion, the channel becomes narrower than in the retention portion.