The Waveco twisting rotor blade can passively adapt to the current direction and flow speed. The Waveco blade twists progressively from the tip to the root and includes the entire blade from the leading to the trailing edge. Under load the twist will be restricted at the tip and will increase towards the root. It will also be self-pitching to the direction of the current and will secure unidirectional rotation in an oscillating current. This twisting blade will present new opportunities for wave as well as tidal power applications. In the Subwave configuration a double counter-rotating rotor is suspended about 100 m below a surface buoy. This can be used for utility scale wave power, but also for powering a self-positioning ocean observation platform. In another application an Orbital-type floating tidal device can be converted to a wave energy device. The efficiency of a Nova Innovation type tidal turbine can be improved by replacing the symmetrical Wells rotor blades with the self-twisting blades. First calculations show that the Waveco twisting blade can be constructed with standard blade construction materials (epoxy or polyester resin with a reinforcement of glass or carbon fibres).