  The self-propulsion of a heavy, superoleophobic, metallic micro-boat carrying
a droplet of various aqueous alcohol solutions as a fuel tank is reported. The
micro boat is driven by the solutocapillary Marangoni flow. The jump in the
surface tension owing to the condensation of alcohols on the water surface was
established experimentally. Maximal velocities of the self-propulsion were
registered as high as 0.05 m/s. The maximal velocity of the center mass of the
boat correlates with the maximal change in the surface tension, due to the
condensation of alcohols. The mechanism of the self-locomotion is discussed.
The phenomenological dynamic model describing the self-propulsion is reported.
