US2103715A - Ship construction - Google Patents

Description

Dec. 28, 1937.`

H. P. FREAR" l 2,103,715

SHIP coNsTRUcTloN original Filed July 19, 1934 4 Sheet'S-Sheet l Dec. 28, 1937. vH. P. FREAR SHIP CONSTRUCTION Original Filed July 19; 1934 4 Sheets-Sheet 2 I gmwntov Dec. 28, 1937. l H. F. FREAR 2,103,715

SHIP CONSTRUCTION Original Filed July 19, 1934 1.4 Sheets-Sheet 5 Dec. 28, 1937. H. P. FREAR 2,103,715

SHIP CONSTRUCTION original Filed July 19, 1954` 4 sheets-snm 4 Patented Dec. 28, 1937 is s u E D 2,103,715

ttt n un SHIP CONSTRUCTION Hugo P. Frear, New York, N. YA., assignor to Bethlehem Shipbuilding Corporation, Ltd., a corporation of Delaware Original application July 19, 1934, Serial No. 735,923. Divided and this application January 15, 1936, Serial No. 59,211

2 claims. (ci. 114-79) This invention relates to improvements in the structure of floating vessels or ships of all types, but especially to vessels designed to carry liquid cargo in bulk, commonly called tankers, and built on the quasi longitudinal system of framing.

Thel present application is a continuation-inpart of my co-pending application Serial No. 688,574, filed September 8, 1933, and is a divisional application of my co-pending application Serial No. 735,923 led July 19, 1934. In another application (Serial No. 59,212 filed concurrently with the present application I have disclosed and claimed broadly the feature of maintaining continuity of strength of longitudinals where cut by the bulkheads and this present application discloses and claims a specific form thereof.

'The chief object of the. present invention is to provide improved means for maintaining continuity of strength in the longitudinals of the ships framing where cut by the bulkheads.

Another object ofthe present invention is to .provide continuity of strength in the longitudinals of the ships framing Where out by the bulkheads by Welding additional metal to connect the ends of the longitudinals where cut by the bulkheads and to have this additional metal of a preferred shape as will hereinafter be described and set forth.

AnotherV object of the present invention is to reduce to normal the unit stresses developed in the ships plating at the line of the transverse bulkheads.

Another object of the present invention is to make a considerable saving in the Weight of the framing of the ship over the usual framing with its initial saving in cost and future savings due to added capacity and reduced tolls.

With these objects in view, the present invention, broadly stated, resides in a ship or the like, particularly for carrying liquid cargo in bulk, in which longitudinal stiffeners are cut at a transverse bulkhead, and in which strength is restored to the stifleners across the bulkhead at the outer portions of ythe stiffeners by plates having edges r welded to the stiffeners and other edges welded to the bulkhead or to boundary bars associated therewith and at the inner portions of said stiffeners by 'a round bar extending watertight through the bulkhead by reason of being welded thereto and welded to the ends of the stiffeners.

By using a round bar at this point I have found that it combines with a high efficiency in increasing the section modulus a particular adaptability to its being welded to the longitudinals, by reason of the angles formed when in contact with the longitudinale which angles are ideal for receiving the weld metal, and by reason of its convenient approach for welding. Furthermore the round section requires only the simplest form of piercing of the bulkhead plating-that of a round hole which may be formed either by means of the Welding torch, or are; or by the more conventional means of drilling or punching.

The novel features will be more fully undertaken with the drawings, in which:

Fig. lis a partial section through a vessel illustrating one form of continuing the strength of longitudinals through the bulkheads;

Fig. 2 is a cross-section taken along the line 2 2 of Fig. 1; K f

Fig. 3 is a cross-section taken along the line 3-3 of Fig. 1; Y

Fig. 4 is a similar view to Fig. 1 illustrating a modication in the bulkhead; Y Fig. 5 is a cross-section taken along 5-5 of Fig. 7;

Fig. 6 is a cross-section taken along the line 6-6 of Fig. 5;

Fig. 7 is a View taken on the line 'I-'I of Fig. 5;

Fig. 8 is a cross-section taken along the line 8-8 of Fig. 1,0 illustrating a further modification;

Fig. 9 is a cross-section taken along the line 9-9 of Fig. 8; l ,y

Fig. 10 is a View taken on the line Ill- I0 kof Fig. 8;

Fig. 11 is a diagrammatic layout of a hold plan of a vessel with transverse and longitudinal bulkheads adapted for longitudinal framing embodying my invention;

Fig. 12 is an enlarged cross-section in part taken on the line I2-I2 of Fig. 11 and illustrates the longitudinal framing;

Fig. 13 is a longitudinal section taken horizontally through a portion of the vessel of Fig. 11 and illustrates the embodiment of my invention toy the ships longitudinals; and

Fig. 14 is a modification of Fig. 4 and embodies my invention in its simplest form.

Referring now to Figures 1, 2, 3, 1l, 12, and 13 the bulkhead plating I0 is shown suitably attached to the bulkhead boundary bar II as by Welding I2. The longitudinal stiffeners I3 have their outer or plating flanges strengthenedand extended in breadth on both sides and toward the ends by means of the flange extension plates I4 welded asl at I5 to the stieners I3. As assembled in the nished vessel the extension plates I4 together with the cut ends of the stiffeners I3 are Welded as at I6 to the plating flanges Il the line stood from the following description and claims l0 of the boundary bar II. Member I8 is preferably a round tie rod passing through the bulkhead plating III and welded or fused to the adjacent ends of the aligned longitudinal stiffeners I3. It is also welded watertight to the bulkhead plating I6 as at I9.

In Fig. 4 I sho-w a modication to the design shown in Figs. 1, 2, and 3. In this modification the boundary bar comprises two angle bars 2lv suitably attached to the bulkhead plating and has the heels of the bars 2I welded together as at 22, and the horizontal flanges of the bars 2| welded, as at 23, to the anges of the stiffeners I3 in a manner similar to that shown in Figs. 1 and 2.

In case it is necessary to provide for drainage through the stiieners, I may do so by means of the slots 24 in Figs. 1 and 2. The edges of the slots are securely welded to the ships plating.

The stifeners I3 are preferably continuously welded to the ships plating as at 25.

The extension plates I4 may be increased or reduced or be limited to one side only of the stileners I3 as the exigencies of interference of plate or other circumstances in design demand.

By reason of the flange extension plates I4 being welded to the stiffeners I3, and both in turn welded to the boundary bar I I, the continuity of strength at the outer flange of the stiffeners I3 is maintained; and by reason of the tie rod I8 welded or fused to the inner flanges of the stiffeners I3 the continuity of strength at the inner flange is maintained. Furthermore by proper proportioning of the extension plates I4 and the tie rod I8 the continuity of strength in the stiffener through the bulkhead both longitudinally and as a beam may be maintained. The pull of the aligned stiffeners I3 is carried through the bulkhead without cutting the boundary bar II or the passing of doublings under the bar, thereby avoiding the objection of increasing the number of plies for riveting and the difficulty of making and keeping tight. The anges I1 of the boundary bar II is neutral as far as performing any longitudinal work on the plating goes, so that the effect of joining the aligned longitudinal stiffeners I3, as described, is to restore the plating to exactly the same condition it would have been in if the stiffeners had not been cut. Furthermore, as broadly disclosed and claimed in my application (Serial No. 59,212) filed concurrently with the present application, by the proper proportioning of the extension plates I4 and the tie rod I8 I am able to make a considerable saving in weight of longitudinals over prior practice. I make this saving, as described in said applica.- tion, by so proportioning the extension plates I4 and the tie rod I 8 that the section modulus thereof adjacent the bulkhead plating shall not be less than the sectional modulus of the stiffeners I3 in way of the web members 2B. The sectional area of the tie rod I8 and the area of the plating between two adjacent stiffener ends is solely used in calculating the sectional modulus. The length of tie rod I8 on either side of the bulkheads along the stiffeners I3, as disclosed in the aforesaid application, is such that it is not short of the point nearest the bulkhead in the stiff'eners I3 where the bending moment of said stiffeners is not less than the bending moment midway between the bulkheads and the nearest web member, or for a distance preferably not beyond the point of inflection nearest the bulkhead. The said two points being respectively approximately 10% and 21% of the distance from the bulkhead to the nearest web member. When thus properly calculated I am enabled to make my stiffeners I3 of the minimum section as determined by the stresses midway between the supports instead of, as: has been the practice heretofore, having the section determined by the stresses at the supports; The saving in weight is readily seen to be an important feature of my invention.

In Figs. 5, 6, and 7 I show a modification to the design sho-wn in Figs. 1, 2, and 3. In this modification the longitudinal stiffeners 2l ccmprise a web plate 28 continuously welded as at 29 along its outer edge to the ships plating 38 and having welded alo-ng its inner edge the reenforcing bar 3|. At the ends of stiffeners 2I where cut by the bulkheads 32 (similar to I of Fig. l) the outer edge of the web plate 28 is coped out to accommodate the flange plate or bracket 33. The cope in the web plate 28 is allowed to extend beyond the end of the flange plate 33 to provide a drain opening 34. The flange plate 33 is welded to the web plate 28 as at 35 and is welded to the ships plating 30 and tothe bulkhead 32 as shown at 36 and 31 respectively.

In Figs. 8, 9, and 10 I show another modification to the design shown in Figs. 1, 2, and 3. The bulkhead 38 and the boundary bar 39 may be similar to that shown in Fig. 1. The longitudinal stiffeners 49 comprise an angle bulb beam. The stiffeners 40 are coped at the ends to accommodate the flange plates 4I in a similar manner as that just described for the stifeners 21.

In still another modification, shown in Fig. 14, it is obvious that one or both of the boundary bars 2l of Fig. 4 could be dispensed with and in such cases the longitudinal stiifeners 42 would be welded directly to the bulkhead 43 by the weld metal 44.

In Fig. 11 I have shown diagrammatically a hold plan of a type of vessel particularly adapted for embodying my invention. The vessel would be constructed with plating on the bottom 45, sides 46, and deck 4T, on the quasi longitudinal system of framing, especially designed to carry a liquid cargo in bulk. It would comprise a plurality of tanks 48 formed by longitudinal bulkheads 49 and closely spaced transverse bulkheads 50 attached to the ships plating 46 and to the longitudinal bulkheads 49. The transverse bulkheads 50 would comprise the plating I0 and the boundary bars II of Fig. 1. Referring now to Figs. I2 and I3, the framing of the vessel would comprise relatively deep and widely spaced transverse webs 26 attached to the ships plating and to the longitudinal bulkheads. The framing would also comprise relatively narrow and closely spaced longitudinal stiffeners 5I. The said stiffeners 5I would comprise the members I3 of Fig. l or its hereinbefore described modification.

The terms and expressions which I have herein employed are used as terms of description and not of limitation, and I have no intention, in the use of such terms and expressions, of excluding any equivalents of the features thereof, but recognize that various modifications are possible within the scope of the invention claimed.

Having thus described my invention what 1 claim as new and desire to secure by Letters Patent, is:

1. In a vessel of quasi longitudinal construction, transverse bulkheads, fore-and-aft walls, watertight means attaching the peripheral edges of said bulkheads to said walls, longitudinal stiieners comprising inner and outer anges cut water-tight means attaching the peripheral edges of said bulkheads to said Walls, longitudinal stiffeners comprising inner and outer flanges cut through by said bulkheads in such a manner that the cut ends are in proximity to but in spaced relation to said bulkheads on each side thereof, and round tie rods piercing said bulkheads and Welded Water-tight and completely around its periphery to said bulkheads and Welded to said inner anges of adjacent cut ends of said 10 stiff eners.

HUGO P. FREAR.

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