Abstract: A transport ship for transporting floatable cargo comprises a hull having a ballast system with a plurality of ballast tanks and with at least one cargo space which is capable of being flooded. The cargo space is closed by at least one sea door. The ballast system is capable of flooding the cargo space and adjusting the ballast of the hull in order to bring the water level of the cargo space level with the surrounding sea so that the sea doors may be opened and the floatable cargo may be floated directly into the cargo space. With the method of the invention, after the vessel is ballasted and the cargo space flooded in order to adjust the level of the cargo space water to the surrounding water level the sea doors are opened and the cargo floated into the space and aligned in stowage position.