To effectively prevent corrosion of the neighborhood of a suction bell-mouth in a ballast tank of a marine vessel and a marine structure.

Ballast tank corrosion preventive members 8, 16 have mounting members 10, 17 to head end parts of plumbing devices 2, 3 and anode members 10, 18, an electric current flows in the sea water which is an electrolyte toward a steel material of an inner wall of the ballast tank which is higher in electric potential than the anode members 10, 18 which are low in electric potential, a vessel's bottom on the high electric potential side comes to be in an anticorrosion state and stabilized and corrosion of a vessel's bottom part near the suction bell-mouth 2 is effectively prevented.

COPYRIGHT: (C)2008,JPO&INPIT