space 44 between them the mid hull section 24 is then built from u201c scratch u201d in the yard space by welding together steel plates until the mid hull section is completed applicant welds steel plates 52 over the front end 50 of the stern section 22 and welds steel plates 54 over the rear end 56 of the bow section to keep out water and to isolate the hydrocarbon tanks on the bow and stern ends from sparks produced by drilling and other equipment on the mid hull section however since the bow and stern sections 20 22 do not have to sail out of the shipyard 40 before being joined to the mid hull section the bow and stern sections do not have to be independently sea worthy then the bow and stern hull sections 20 22 are moved against the front 46 and rear 48 ends of the mid hull section and welded to the mid hull section to produce a tandem connected hull 49 fig1 topside equipment is installed primarily on the mid hull section the fpso 36 fig2 which is converted to a fpdso was initially constructed to provide sufficient strength to withstand the weight and forces encountered by the fpso but not those encountered.