PURPOSE: To prevent waves from getting out of shape in order to reduce hull resistance, by providing nozzles adjacent to water surface near a stem and a stern so that the fluid can be sucked in directions to accelerate the flow of surface water and the sucked water can be jetted reaward.

CONSTITUTION: The sucking nozzles 11 are provided at adjacent water surface where waves are liable to get out of shape such as points adjacent to the stem part, the stern part and stem and stern shoulders to suck water by pumps 13 to accelerate the flow of surface water, and the sucked water through the nozzles 11 is jetted from jetting nozzles 15 via discharging pipes 14 to accelerate the flow of the surface water. As the surface water is accelerated, its flow is given momentum, the getting-out of shape of waves can be reduced, the loss of water head can be reduced, and therefore the hull resistance can be decreased as a whole.