An ocean current turbine for converting water currents' energy, comprising the following features: - a main frame arranged to stand submerged in a water current in the sea or in a river, - wherein the main frame comprises - a bow part arranged to face directly towards the water current, - one or more starboard and port endless rotation chains with plates arranged to being captured at the bow part and driven rearward by the water current, - wherein each of the one or more starboard and port endless rotation chains runs about and in driving engagement with one or more driven wheels that operates a generator, and - port and starboard side frames (PS, PP) that are continuously convex and extends from the bow part and rearward to - a transverse wide stern part that is narrower than the greatest distance between port and starboard side frames (PS, PP), - wherein the one or more starboard and port endless rotation chains comprise a starboard endless rotation chain and a port endless rotation chain wherein each of the starboard endless rotation chain and the port endless rotation chain is provided with the plates, arranged to run along the starboard and port side frames (PS, PP), and - a turning mechanism arranged to turn each plate to catch the water current at the bow part, so that each plate is driven rearward along the starboard, respectively port side frame (PS, PP), back to the rear by of the wide stern part, and where the turning mechanism turns each plate to a passive state where the plate does not substantially catch the water current when the plate is led forward again by the starboard endless rotation chain or the port endless rotation chain in a shielded cavity between starboard and port side frames (PS, PP) and extending to the bow part, whereby that the bow part forms a wide shield forming a width corresponding to between 1/4 and 1/2 of a length of a largest width of the main frame, and which follows the starboard and port side frames (PS, PP) backwards to a point where a water velocity along the port and starboard side frames (PS, PP) is greater than an initial speed of the incoming water current. - a main frame arranged to stand submerged in a water current in the sea or in a river, - wherein the main frame comprises - a bow part arranged to face directly towards the water current, - one or more starboard and port endless rotation chains with plates arranged to being captured at the bow part and driven rearward by the water current, - wherein each of the one or more starboard and port endless rotation chains runs about and in driving engagement with one or more driven wheels that operates a generator, and - port and starboard side frames (PS, PP) that are continuously convex and extends from the bow part and rearward to - a transverse wide stern part that is narrower than the greatest distance between port and starboard side frames (PS, PP), - wherein the one or more starboard and port endless rotation chains comprise a starboard endless rotation chain and a port endless rotation chain wherein each of the starboard endless rotation chain and the port endless rotation chain is provided with the plates, arranged to run along the starboard and port side frames (PS, PP), and - a bow part arranged to face directly towards the water current, - one or more starboard and port endless rotation chains with plates arranged to being captured at the bow part and driven rearward by the water current, - wherein each of the one or more starboard and port endless rotation chains runs about and in driving engagement with one or more driven wheels that operates a generator, and - port and starboard side frames (PS, PP) that are continuously convex and extends from the bow part and rearward to - a transverse wide stern part that is narrower than the greatest distance between port and starboard side frames (PS, PP), - wherein the one or more starboard and port endless rotation chains comprise a starboard endless rotation chain and a port endless rotation chain wherein each of the starboard endless rotation chain and the port endless rotation chain is provided with the plates, arranged to run along the starboard and port side frames (PS, PP), and - a turning mechanism arranged to turn each plate to catch the water current at the bow part, so that each plate is driven rearward along the starboard, respectively port side frame (PS, PP), back to the rear by of the wide stern part, and where the turning mechanism turns each plate to a passive state where the plate does not substantially catch the water current when the plate is led forward again by the starboard endless rotation chain or the port endless rotation chain in a shielded cavity between starboard and port side frames (PS, PP) and extending to the bow part, whereby that the bow part forms a wide shield forming a width corresponding to between 1/4 and 1/2 of a length of a largest width of the main frame, and which follows the starboard and port side frames (PS, PP) backwards to a point where a water velocity along the port and starboard side frames (PS, PP) is greater than an initial speed of the incoming water current.