PURPOSE: To improve rigidity of the hull in such a way that a rising part is formed at the opening extremity of the deck of a motor boat constituted by FRP, which is overlapped with a steering wheel stand 6 made to be a strengthened material by fitting a windshield at the upper part of the rising part.

CONSTITUTION: A rising part 21b is formed at the opening extremity of a cockpit part of the deck 2 of a motor boat composed of the bottom 11, board sides 12, the deck 2, which is overlapped and bonded with a steering wheel stand 6 to be fixed a steering wheel, meters, etc. A windshield 3 is installed at the upper part of the rising part 21b. Because the steering wheel stand 6 is strongly bonded with the rising part 21b of the deck 2, it functions as a strenghened member, to be able to increase the rigidity of the hull 1.