Double bottom Floors

Vertical transverse plate floors are provided both where the bottom is transversely and longitudinally framed. At the ends of bottom tank spaces and under the main bulkheads, watertight or oiltight by closing any holes in the plate floor and welding collars around any members which pass through the floors. Elsewhere ‘solid plate floors’ are fitted to strengthen the bottom transversely and support the inner bottom. These run transversely from the continuous centre girder to the bilge, and manholes provided. Lightening holes are cut in each solid plate floor. Also small air and drain holes may be drilled at the top and bottom respectively of the solid plate floors in the tank spaces. The spacing of the solid plate floors varies according to the loads supported and local stresses experienced. At intermediate frame spaces between the solid plate floors, ‘bracket floors’ are fitted. The bracket floor consists simply of short transverse plate brackets fitted in way of the centre girder and tank sides (see Figures 10 and 11).