PURPOSE: To provide a hull structure of nonmetallic material, particularly, reinforced plastic material in a simple, light and strong construction for a boat, a ship or a mine sweeper.

CONSTITUTION: A hull structure includes a plurality of cross ribs 3 provided with an outer shell 1 and at least one of decks 2, 2' and extended along the cross section of the outer shell 1 and a plurality of cross members or beams 4, 4' extended over the lower faces of the decks. The cross ribs 3 and the cross members 4, 4' are joined to the outer shell 1 and the decks 2, 2', respectively, and mutually connected 103, 203 and the cross rib 3 are mutually connected to members (girders) 15, 15' passing through a partition wall 5 and continuous from a stem to a stern to form an integrated unit framework together with a keel.