PURPOSE: To enlarge cargo loading space and make loading and unloading work efficient by a method wherein unit accommodation quarter and a navigation module are attached detachably to the upper part of containers loaded on an upper deck.

CONSTITUTION: The unit accommodation 11 and the navigation module 14 provided with a radar and communication equipments, whose sizes are designed so as to correspond to the size of the containers 12 loaded on the upper deck 15, are attached to the upper part of the containers loaded on the upper deck 15. The accommodation is connected to the upper deck 15 and an engine room 13 through a traffic tube 16 while the inside of the tube 16 is arranged with steps, lifts, electric wires and the like. According to this method, the cargo loading space may be enlarged as a whole and the loading and unloading works will never be bothered by the accommodation and the navigation module.