US2743694A - Welded ship hull construction - Google Patents

Description

May 1, 1956 J MCALEER 2,743,694

WELDED SHIP HULL CONSTRUCTION Filed Feb. 26, 1952 IN VENTOR United States Patent WELDED SHIP HULL CUNSTREKIHON John A. McAleer, Weymouth, Mass. Application February 26, 1952, Serial No. 273,436 1 Claim. ((31. 114- 79) This invention relates to that class of floating structures in which the hull stresses and its resistance to deformation therefrom are carried by the shell or enveloping plating assisted by seam members or means, placed on the inside of all longitudinal plating seams, both plating and seam reinforcement being in functional relation with rigid frame, open panel transverse girders, in which equilibrium of action between the chords is maintained by moment resisting joints and struts.

One of the objects of this invention is to provide a simple system of shell support that is light in weight, simple and economical to construct and with less than the usual amount of transverse material in contact with the outside shell; thus producing in a Welded or partially welded structure a surface of plating freer of contraction wrinkles, lying across the general flow of frictional resistance.

The primary members are initially unstable and of a floating or flexible type, yet when temporarily spaled or braced they permit the contouring and shaping of a rigid floating structure of any required conformation. To keep the inner chords of the primary stiffeners in their proper shape until the inner seam butt means, which also act as fairing ribbands, and the shell plating or enough of it, are located in place and welded, these inner chords are pinned down on the slab to shape, in opposite pairs, welded to their common floor bracket and then spaled or braced to their moulded shape so that they can be used as true permanent moulds of the vessels lines. When sufficient plating has been erected and fastened in place so that the true shape is assured, these temporary spals can be removed. A transverse strip of the applied plating will then provide the corresponding flange to the inner chord.

A further advantage of using this rigid open panel transverse frame herein shown, in combination with the reinforced longitudinal plating seams is that this con bination of stiffening creates a semi-monocoque or stressed skin type of construction in which by controlling the panel sizes of the enveloping shell, the shell can be more uniformly and therefor more highly stressed than heretofore. The hull will have less transverse welding running across the direction of flow and therefor less wrinkling and less tendency to a Euler type of failure through shell buckling. I am well aware that the combination of light and heavy support members in all types of structures is not new but my improvement consists in the combination of a special type of both the heavy and the light members and their purpose is to produce in a welded or partially welded structure not only a structure stronger per pound of metal due to its fairness but economical in labor hours to erect and plate.

The accompanying drawing illustrates the application of the invention to the shell support of floating structures, the longitudinal inner shell seam straps or butt means being disposed parallel generally to the direction of travel or motion and the heavier primary frames being disposed substantially at right angles thereto.

While the drawing and the specifications might suggest a welded connection of the intermediate web mem bers to the enveloping shell, I do not Wish to limit myself to this as in a particular case it might be preferable to weld to a riveted clip or to a welded clip, or to an inside transverse doubler, if the functional strip of plating in the outer chord should require it.

The longitudinal butt straps may also be T bars as well as flat bars or other sections that special conditions might demand and the same is also true of the primary stiit'eners and the latter may be canted in the ends so that they may lie more nearly normal to the shell plating.

Referring to the accompanying drawing, showing a portion of such a structure, 1 is a flat plate keel, although such a type of keel is not mandatory, 2 is a center plate keelson and 3 is a center plate keelson floor bracket connected to the center keelson by an egg crate construction and welded; 4 is the inner chord of a primary transverse frame, connected directly to the longitudinal seam straps 8 and to the shell indirectly by the Web members 5, these web members being suiiicient of themselves and by their connections to the inner chord it and to the shell 6 to take the required shear and moment. 6 is the shell plating with its longitudinal scams 8 coming on the longitudinal seam butt straps 7. 10 represents the deck stringer angle andv 9 represents wood nailing strips, fastened to the inverted beams 12 so that a wood deck can be easily applied if required. 11 shows a stanchion placed at the primary members which also have a. bracket as shown at 13. The deck house co-azning plate 15 stiffened by inverted angles 14 and 16 represents the top bars of the center vertical keelson 2, both in the usual manner.

Having thus described my invention 1 claim as follows:

A welded hull structure comprising a shell of generally curvilinear cross section, said shell comprising longitudinally extending plate members, seam Welds extending longitudinally therebetween, angle straps overlying and welded to said seam welds, chord members constituting frame elements positioned within said shell spaced from each other and from the shell, the spacing from the shell being greater than the depth of the angle straps, said frame elements extending transversely of the shell, web members positioned perpendicular to the shell and to said chord members and welded to each and certain of said web members welded to the angle straps, other of said web members being positioned intermediate said straps and free of attachment thereto whereby said chord members and said webs form open girders and coact with the slcin to contribute structural rigidity to the hull com- I ponents.

References Cited in the file of this patent UNiTED STATES PATENTS 1,029,546 lsherwood June 11, 1912 1,805,669 Liatnin May 19, 1931 1,923,544 Leonard Aug. 22, 1933 2,058,282 Whitese-ll Oct. 30, 1936 2,142,945 Kjekstad Jan. 3, 1939 2,644,418 Allegro July 7,, 1953 FOREIGN PATENTS 4,729 Great Britain of 1878

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