Abstract: In a modularly constructed longitudinal midbody of a double-hulled tanker, each module is provided, along the vessel centerline, with a prefabricated subassembly including a keel portion of the double hull structure, and a pipe tunnel containing virtually all equipment, piping and nonstructural components required to be installed below the vessel's upper deck to serve the cargo tanks and ballast tanks within the respective module. Each subassembly extends throughout the length of the respective module and respective of its features are connectable at the module ends with the comparable features of adjoining modules. The subassembly may serve as the base for a longitudinal bulkhead.

Abstract: A double-hull tanker having one or more cargo tanks is structured so as to have compartments surrounding each cargo tank in the form of between inner and outer hulls, and possibly between cargo tanks. These surrounding compartments are normally empty when the tanker is carrying a cargo of oil, or a similar largely water immiscible, lighter-than-water flowable liquid cargo. The volume of the cargo tank or tanks above a level equal to 111 percent of the assigned draft (Vc) of the vessel, is less than the volume of that cargo tank's surrounding compartments below that same level (Va). Because the hydrostatic equilibrium level for typical specific gravity ranges of crude oil and seawater is at least 111 percent of a vessel's maximum allowable operating draft, the compartments provide sufficient volume to contain all oil which might leak from a cargo tank during grounding damage.

Abstract: In a double-layered vessel wall construction, which has two transversally spaced longitudinal wall layers, and wall layer-connecting plates, each of which has one longitudinal edge weldingly joined in a plate edge-to-plate edge joint in one of the longitudinal wall layers, and an opposite longitudinal edge weldingly joined in a plate edge-to-plate edge joint in the other of the longitudinal wall layers, so as to divide space enclosed by the wall construction into a plurality of cells that are typically closed at opposite ends by transverse bulkheads, cell-to-cell access openings are longitudinally staggered and located near cell ends. Accordingly, forced air ventilation can sweep through virtually all of the space enclosed within the wall construction, and a worker who falls while climbing from one cell to another via an access hole can fall no further than the vertical extent of the two cells which are interconnected by that access opening.

Abstract: The fixtures in which curved and reinforced flat plates are held while being welded, cleaned, coated and cured include fixedly mounted exterior towers and interior towers removably mounted on rollable bogies (i.e., rail cars or carriages) for ease of transport through a succession of work stations. Subcomponents fabricated on respective bogies are weldingly joined to form module subassemblies after coupling and maneuvering the respective bogies to align the subcomponents (i.e., units). A transverse bulkhead is supported on fluid cushion pallets beside the bogie-supporting rails, so that the transverse bulkhead can be positioned for welding of each subassembly thereto, to provide each respective double-walled vessel hull midbody module.