Abstract: A hopper vessel for storing bulk material such as dredged material, has one or more holds. The holds in their bottom are provided with trap doors that open by moving downwardly below the bottom of the vessel. In shallow water, there is the risk that these trap doors, when moved downwardly, will contact the bottom or the material that is deposited from the hopper vessel on the bottom. Therefore, some of the trap doors in the hold are at a higher level in the closed position than the other trap doors. To discharge material, the higher trap doors are opened first; and after enough material has been discharged that the vessel rises sufficiently high in the water, only then are the lower trap doors moved to open position to complete the discharge of the material. The higher trap doors are provided at the ends of the hold. This allows adjusting the angle of the vessel if the bottom of the body of water is sloped.

Abstract: A floating device such as a hopper dredge having bottom valves (4-11) for discharging the holds (2), which holds according to the invention can be closed airtight and are provided with apparatus (18) to generate an overpressure within the holds (2), the bottom valves preferably being at a level above the keelline (3) of the device. Movable crane devices (24,26) are provided within the hold to handle components. The holds (2) have a hatch opening with cover (21) to allow entrance or removal of parts (8') which hatch opening can be covered by an inflatable tent (27) attached to the deck.