TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Components: The linear path is perpendicular to a wind direction (2). Each vessel is symmetrical with respect to an axis perpendicular to the linear path.The control system further comprises a position determining system for determining a position of the vessel.The position determining system comprises a global positioning system receiver provided on the vessel.The operation section operates the control section in accordance with an output of the position determining system. It is provided on a control vessel separate from the series of vessels.The power generation system comprises turbine(s) (13) provided below the floating vessel(s) to be submerged in the water, which is rotated by water flowing through when the floating vessel is moved relative to the water by the sail(s); and a generator for converting rotation of the turbine(s) into direct current (DC) electricity.The onboard hydrogen production system comprises an electrolysis-type hydrogen generator operated by the electricity generated by the generator. It may comprise a reversible fuel cell operated by the electricity generated by the generator.The first controller comprises control component(s) coupled to the sails to change the position of at least one of the sails. The control component changes the position of all the sails.The second controller comprises rudder(s) provided at each end of each vessel.At least one inflatable hydrogen storage container (19) is arranged to be inflated with produced hydrogen. It is detachably and replaceably connected to the vessel(s). A collection vessel collects inflated hydrogen storage containers, inflated with the produced hydrogen, from the vessel(s).The hydrogen storage container is detachable and replaceable while the vessel is in motion. The inflated hydrogen storage containers are lighter than air. They are adapted to float on a water surface.The power generation system comprises wheel(s) connected to the floating vessel(s) to be partially submerged in the water, wherein the wheel is rotated when the floating vessel is moved relative to the water by the sail; and a generator for converting rotation of the wheel into electricity.