A turbine which incorporates intake and exhaust pipes that prevent the passing flow from interfering with, or impeding the operation of the turbine. An optional directional cone, with optional helical supports, mounts within the intake pipe and channels flow at an optimal angle to the turbine blades as well as to the outermost, from the axis of rotation, area of the blade's surface, increasing torque and thus efficiency. The turbine's blades are affixed to the inner surface of a cylindrical shell that is free to rotate within a supporting structure. The cylindrical shell also contains the stationary intake and exhaust pipes. The vacant axis of rotation can be closed or open, by means of shorter blades that form a hole with the distal edges of the blades to allow for passing fish and debris to safely exit. Rotational energy is transferred from the outer surface of the cylindrical shell by gears or belts.