Patent ID: 8633609

Claim:
An apparatus for generating electricity from a natural water current in a body of water, the apparatus comprising: a turbine body having a central axis, the turbine body configured to be disposed in the body of water; a rotor mounted on the turbine body for rotation about the central axis, the rotor including a central hub supporting a plurality of blades, each blade of the plurality of blades extending from a blade root mounted on the hub to a blade tip, the rotor configured to be rotated by the natural water current within the body of water, the natural water current flowing parallel to a surface of the body of water; a generator driven by the rotor, the generator configured to generate electricity; and a cowling, an internal wall of the cowling surrounding the rotor, the cowling configured to direct the natural water current towards the plurality of blades, the cowling defining a flow channel having a flow restriction, the flow restriction forming a convergent-divergent venturi, tapering from a first opening at a first end of the flow channel and a second opening at a second end of the flow channel towards an inner part of the flow channel; a plurality of support struts configured to support the generator in a central position within the flow channel, each support strut from the plurality of support struts extending tangentially outward from the generator to the internal wall of the cowling, the plurality of support struts being located directly downstream of the plurality of blades, the generator being located directly downstream of the plurality of support struts, each support strut from the plurality of support struts defining a hollow duct within which at least one of an electrical line or a hydraulic line can be disposed; and a ballasted foot configured to be located on a floor of the body of water, the ballasted foot including a plurality of equally-spaced platform members and a vertical pylori, the vertical pylori disposed between the cowling and the ballasted foot and configured to support the cowling in the natural water current, wherein each blade root of the plurality of blades includes a plug coupled thereto and configured to reduce interference to water flow, each blade tip of the plurality of blades is disposed adjacent to, but not contacting, the internal wall of the inner part of the flow channel, and each blade of the plurality of blades is raked in a downstream direction from the blade root to the blade tip by a downstream rake angle of 1° to 20° from a vertical plane, the vertical plane perpendicular to the central axis.