Abstract: In most ships or other marine vessels the hull has a double bottom, hull sides and at least one deck. The hull of the invention has at least two fore-and-aft arranged hollow cylinders with considerable buoyancy and constituting an integral part of the double bottom. All plating of the hull is plane, single bent or cylinder casing-shaped. The assembly of the hull is carried out on the surface of a protected water area and is commenced by floating the assembled hollow cylinders on the water surface in parallel relation to each other. The cylinders are then used as a base for assembling prefabricated building sections which are connected successively to the cylinders and/or to each other until the hull is completed.