To simplify the work for setting a hull utilized floating wave extinguishing bank by arranging wave extinguishing plates from about a bow to about a stern in parallel to the hull center line on the outside of a hull, and lowering the lower edge of the wave extinguishing plate down over the lower surface of the bottom by use of a guide member and a lifting means mounted on a broadside part.

A number of plate members 4 are arranged in parallel to the hull center line on the outside of a hull 1. A guide member 2 having a guide groove fitted to the edge of the plate member 4 to vertically guide it is mounted on the broadside through a frame 3 in the bow end part and the stern end part, and directly in the hull parallel part. A crane 5 provided on the ship suspends the plate member 4 through a wire 5a, and lowers the plate member 4 to a required depth under the bottom lower surface. Thus, the cutting work of the bow part or stern part for preventing the permeation of wave or the work for injecting ballast water into the hull is dispensed with, and the work for setting a hull utilized floating wave extinguishing bank can be simplified.