Open-bottom gravel dump boat
 A hull construction of a cargo carrier vessel, with self-propelling capacity, capable of carrying earth, sand, quarried stones and so forth and of disposing of them from the bottom is disclosed. While the bottom (11) is released, the hold forms a double-hull construction with side walls (12). A pair of right and left doors, each with an L-shaped section, is provided. The upper part of each door is connected by hinges to outsides of the side walls of said hold. The doors curve and extend along the released bottom. Cargo is carried in the hold (1). Furthermore, a door structure to dispose of cargo from the released bottom into the sea by releasing it to the right and left and equipment to open and close the pair of doors, located at the front and back of the door structure, is provided. 
Marusen Co., Ltd.
B
B63B
inventional
Toshifumi
Mori