A method for converting kinetic energy in horizontal currents of naturally occurring fluids above ground into mechanical energy. A circulating element is guided in a closed cycle and is arranged substantially in a plane parallel to the ground. The circulating element has two lengthwise adjustable traction ropes/chains fastened in two opposite positions. The ropes/chains have buoyancy elements at their free ends. The buoyancy elements have cross-sections for the current to impact. In an embodiment, a traction rope/chain fixed to a section of the circulating element facing the horizontal current is adjusted to be longer than the traction rope/chain fixed to a section of the circulating element facing away from horizontal current. The lengths of the two traction ropes/chains in the region of the points of return of the circulating element are reversed upon which the course of the circulating element relative to the horizontal current is reversed, when seen in the direction of circulation of the circulating element.