Abstract: Current energy is converted into shaft power in two stages;First, buoyant power units with stationary hydrofoil wings reach faster than the current speed by sweeping out a captive path.Second, turbines at said power units convert the fast relative local current into shaft power.Power units sweeping along the water surface, using cycloidal turbine methods, as well as power units sweeping on a submerged path, using axial flow turbine methods, are described.

Abstract: A waterbound facility, serving the extraction of energy from the water current in which it is moored, consists of a seaworthy vessel, which carries cycloidal turbines, extending their impeller blade assemblies through the vessels bottom into the current. Deployable shrouding, guide vanes and underwater sails serve the concentration of flow. Retractability of turbines and ballast tanks provide draft control for entering harbors.