Vessel hull and construction method

A vessel hull construction, comprising:

• a plurality of like modules serially weldedly connected end-to-end to provide a parallel midbody having two opposite ends, each said module comprising:
• a first plurality of outwardly convex, cylindrically arcuate steel plates welded to one another in series at joints along respective adjoining longitudinal edges to provide an outer hull having a bottom and two laterally opposite sides with one interruption located medially of said bottom of said outer hull;
• a second plurality of outwardly convex, cylindrically arcuate steel plates, welded to one another in series at joints along respective adjoining longitudinal edges to provide an inner hull having a bottom and two laterally opposite sides with one interruption located medially of said bottom of said inner hull;
• said inner hull being arranged within said outer hull so that the bottom of said inner hull spacedly confronts the bottom of said outer hull and the laterally opposite sides of said inner hull spacedly confront the respective laterally opposite sides of said outer hull;
• a plurality of longitudinal steel rib plates arranged between said inner and outer hulls and each having an outer longitudinal edge welded in a respective said joint between two plates of said first plurality of steel plates and an inner longitudinal edge welded in a respective said joint between two plates in said second plurality of steel plates;
• a medially arranged, longitudinally extending duct keel disposed in both said interruptions and weldedly joined to longitudinal edges of respective adjoining plates of said first and second plurality of steel plates;
• a transverse bulkhead located within said inner hull and having an outer perimeter welded to a plurality of the plates of said second plurality of steel plates;
• and
• said inner hull and outer hull having two longitudinally opposite ends and said bulkhead being provided at one of said ends of said inner hull.

A parallel midbody for a double-hulled vessel, comprising:

• a first set of at least two steel plates each of which is substantially rectangular in plan so as to have two long edges and two short edges, and curved by being arcuate about an axis that is substantially parallel to said long edges, said first set of steel plates being arranged long edge adjacent to long edge to form respective parts of an outer hull, with said curved plates each being convex outwards throughout the entire width thereof from one said long edge thereof to the other said long edge thereof;
• a second set of at least two steel plates each of which is substantially rectangular in plan so as to have two long edges and two short edges, and curved by being arcuate about an axis that is substantially parallel to said long edges of said plates of said second set of steel plates, said second set of steel plates being arranged long edge to adjacent long edge to form respective parts of an inner hull, with said curved plates of said second set each being convex outwards throughout the entire width thereof from one said long edge thereof to the other said long edge thereof;
• said second set of steel plates being arranged in spacedly confronting relation to said first set of steel plates, with respective adjacent long edges of steel plates in said second set substantially aligned with and laterally in substantially registration with respective adjacent long edges of steel plates in said first set to provide at least one plate-to-plate joint site for each of said outer and inner hulls;
• a third set of at least one steel plate, each of which is substantially rectangular in plan so as to have two long edges and two short edges;
• each steel plate of said third set being arranged between said inner and outer hulls with one said long edge thereof juxtaposed with a plate-to-plate joint site of said outer hull, and the other said long edge thereof juxtaposed with a corresponding plate-to-plate joint site of said inner hull, so that three long edges of three different ones of said plates are juxtaposed at each said plate-to-plate joint site;
• at each said plate-to-plate joint site, the respective said three long edges being welded together to provide a respective welded T-joint;
• and
• a transverse bulkhead having an outer perimeter welded to a plurality of the steel plates of said second set.

A longitudinal subassembly fixture for fabricating like bottom and side subassemblies for modules for a parallel midbody for a double hull vessel, said fixture comprising:

• three rows of vertical towers having fixed bases, including one inner row, and two outer rows located on opposite sides of said inner row;
• each tower in said inner row having four working faces, including two facing respective ones of said outer rows, and two facing in opposite directions along said inner row;
• each tower in said outer rows having one working face facing towards said inner row;
• each working face having mounted thereto a respective frame means arranged in pairs such that each frame means on a tower in an outer row spacedly confronts a frame means on a tower in said inner row, and such that each frame means on an inner row tower which is provided on a face which faces along said inner row spacedly confronts another said frame means on an adjacent said inner row tower;
• each frame means in each pair being mounted to the respective tower by jack means for movement towards and away from the respective tower, so that within each pair of frame means, each frame means can be forced into closer relation with the other and released to move away from the other;
• within each pair of frame means, the two respective frame means being provided with complementary surfaces for engaging and holding between them with a predetermined shape and spatial orientation a respective plate;
• and
• means mounted to said towers for welding vertical T-joints between respective abutting edges of respective groups of three plates while two of such plates are engaged and held between adjoining pairs of frames means respectively mounted one frame means to a tower in said inner row and a tower in said outer row and while the other one of such plates is engaged and held between a respective pair of frame means respectively mounted one frame means each to two adjoining towers in said inner row.

Apparatus for assembling a bulkhead with a plurality of longitudinal subassemblies for a module for a parallel midbody for a double hull vessel to provide said module, comprising:

• an underwater grid of upright pilings providing a submerged support surface means;
• a variable buoyancy barge overlying said submerged support surface means and being adjustable between a floating mode in which said barge is floating above said submerged support surface means and therefore is susceptible to being rotated about a vertical axis, and a sink mode, in which said barge is firmly grounded on said submerged support surface means;
• means for supporting a horizontally extending bulkhead on said barge;
• means for providing a succession of longitudinal subassemblies for a module for a parallel midbody for a double hull vessel laterally adjacent but spaced from said submerged support surface means;
• a derrick juxtaposed with both said subassembly providing means and said submerged support surface means said derrick being of sufficient capacity to lift said subassemblies singly from said subassembly providing means and set each in place on said barge perimetrically of said bulkhead, whereby said barge may be floated and rotated between uses of the derrick to place said subassemblies successively thereon, and may be disposed in said sunk mode while each subassembly is loaded thereonto by said derrick, and whereby said subassemblies may be welded to one another and to said bulkhead while disposed on said barge.

A vessel hull construction method, comprising:

• (a) providing a first set of cylindrically curved rectangular steel plates serially arranged edge-to-edge, all convex in one direction with all axes of curvature vertically oriented;
• (b) providing a second set of cylindrically curved rectangular steel plates serially arranged edge-to-edge, all convex in said one direction with all axes of curvature vertically oriented;
• (c) providing a further set of vertically arranged rectangular steel plates each having one longitudinal edge disposed adjacent edges of two adjoining ones of said steel plates in said first set and an opposite longitudinal edge disposed adjacent edges of two adjoining ones of said steel plates in said second set to provide respective T-joint sites;
• while holding each said plate by engagement with both opposite faces thereof for maintaining a desired shape and position for each said plate, welding a respective T-joint at each said T-joint site;
• and
• (d) releasing said plates from being held, and thereby obtaining a double-walled hull subassembly.