US 5,090,351 A · Vessel hull construction and method

Abstract

An improved curved-plate, double-hull tanker construction is provided, having reduced or eliminated transverse reinforcing structure in its midbody, except for bulkheads. The hull, though double, can compare in weight to conventional single hulls, despite being entirely made of mild steel plate. It is made of significantly fewer pieces, with a reduction in welding footage. More of the steel is used in the form of plate, rather than more expensive shapes. Improved productivity is possible, resulting from standardization of parts, less scrap, greater use of jigs and fixtures, automated welding, blast-cleaning and painting, so that not so much staging is needed, the work environment can be safer, and the product can be produced at a lower unit labor cost. Preferably, cathodic epoxy painting is used for durability and reduction in problems due to blast cleaning, solvent evaporation and generation of refuse. Extending the double hull structure from the bottom and sides of the hull to the main deck can provide space for fuel oil to be located safely away from the skin of the ship, rather than in possibly vulnerable deep tanks at the stern. The constructional technique is believed to be applicable to vessel hulls in the 70,000 DWT to 300,000 DWT range. The vessel hull midbody module subassemblies may be assembled into modules, hull midbodies and vessels using the method and apparatus disclosed in Cuneo et al., Application No. 07/532,329.

A method for fabricating a module structure for a double-hulled vessel, comprising:

(a) providing a plurality of flat plate panels, each being elongated rectangular in outer perimetrical shape so as to have two opposite side edges, two opposite end edges, and two opposite flat faces;
(b) providing a plurality of curved plate panels, each being elongated rectangular in outer perimetrical shape so as to have two opposite side edges, two opposite end edges and two opposite correspondingly generally cylindrically arcuately curved faces, so that each curved plate panel is concave in one direction and convex in an opposite direction about an axis parallel to said side edges;
(c) mounting a longitudinally extending series of transversally extending stiffener plates to at least one face of each flat plate panel, so as to provide a plurality of stiffened flat plate panels;
(d) providing each curved plate panel and each stiffened flat plate panel with an all-over, cured coating of paint to provide respective painted panels;
(e) providing a fixture as an array of upstanding towers fixed on a foundation;
(f) vertically disposing in said fixture, among said towers, a first plurality of said painted curved plate panels, arranged in a first series, in which individual ones of these panels spacedly adjoin one another, side edge to side edge, with respective gaps between them, in a single layer;
(g) vertically disposing in said fixture, among said towers, a second plurality of said painted curved plate panels, arranged in a second series, in which individual ones of these panels spacedly adjoin one another side edge to side edge, with respective gaps between them, in a single layer, so that gaps between panels in said second series are substantially in registry with gaps between panels in said first series, thicknesswise of said fixture;
(h) vertically disposing in said fixture a plurality of said painted stiffened flat plate panels arranged in a series, in which one side edge of each painted stiffened flat plate panel adjoins a respective said gap in said first series of painted curved plate panels and an opposite side edge thereof adjoins a respective said gap in each said second series of painted curved plate panels;
(i) supporting said panels in each of said series of panels with respect to respective ones of said towers of said fixture;
(j) welding joints between and among respective ones of said panel side edges in respective ones of said gaps, thereby filling said gaps and uniting said panels in said fixture into a double-hull module subassembly having a plurality of longitudinally extending cells of generally rectangular transverse cross-sectional shape and two laterally opposite ends where side edges of respective terminal ones of said painted curved plate panels are available;
(k) removing support of said fixture from said panels of said subassembly and removing said subassembly from said fixture;
and
(l) repairing damage caused in step (j) to said cured coating of paint both externally of said subassembly and internally of said cells, at internal corners of respective ones of said cells.

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Vessel hull construction and method

Life of this patent

Vessel hull construction and method

Life of this patent

Abstract

Claims29