An ocean power plant for converting slow water flow energy with a turbine comprising at least one endless rotation chain (4) with a plurality of plate holders (2) along the rotation chain where the plate holder comprises at least one plate (1) attached in each plate holder, further, the rotation chain running in an extended lane around and engaging at least one drive wheel (5) in the one end arch of the web tiltably attached to the plate holder to alternate between open position with the primary flow direction of the water flow, and closed position towards the flow direction, and the drive wheel has a turbine shaft (7) coupled to a generator device (G), an electrical generator or a converter of the rotational energy to hydraulics or other type of mechanical or potential energy, for the utilization of the rotational energy, furthermore the path of the rotary chain (4) is tilted relative to the main flow direction of the water flow, all arranged in a fully or partially submersible support structure (100).