PURPOSE: To obtain a bulwark structure through solid forming by a method wherein a horizontal staged part, a vertical part and another horizontal staged part are formed consecutively in the upper part of an outer board part on the solidly-formed side of a small-sized vessel of FRP make such as a fishing boat and a gunnel member is fitted to the horizontal staged part at the top.

CONSTITUTION: In a small-sized vessel, such as a finishing boat, constituted by FRP through solid forming, a staged part 14 is formed by bending horizontally the upper part of the outer board part 1 of the side of the vessel and then a vertical part 10 is formed at the tip of the staged part 14, and further at the tip of the part 10 a member formed of a horizontal part 13 to the tip of which a gunnel member 4 is fitted is prepared by solid forming. To the solidly-formed structure of a hull is fitted a deck 2 through the intermediary of sealing materials 6 and a support material 5. By this, the stiffness of a bulwark can be raised, while the preparation of the vessel being facilitated.