US2053903A - Ship construction - Google Patents

Description

H. P, FREAR Sept. 8, 1936.

Filed Sept.-8, 1933 6 Sheets-Sheet 1 S11/vento@ Sept. 8, 1936. H, P. FREAR SHIP CONSTRUCTION Filed Sept. 8, 1935 6 Sheeinjhe 2 mv @www IVZZH Sept. 8, 1936. H. P. FREAR 2,053,903

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Sept. 8, 1936, H, P. FREAR SHIP CONSTRUCTION Filed Sept. 8, 19555 6 Sheets-Sheet A Sept. 3, 1936. H. P. FEAR 2,053,903

SHIP CONSTRUCTION Filed Sept. 8, 1935 6 Sheets-Sheet 5 Sept. 8, 1936. H. P. FREAR SHIP CONSTRUCTION Filed Sept. 8, 1935 6 Sheets-Sheet 6 Patented Sept. 8, 1936 UNITED STATES SHIP CONSTRUCTION Hugo P. Frear, New York, Y., assignor to Bethlehem Shipbuilding Corporation, Ltd., a corporation of Delaware Application September 8, 1933, Serial No. 688,574

- 8 Claims.

My invention relates to floating vessels or ships and particularly to vessels for carrying cargo in bulk.

In vessels adapted to carry liquid cargo in bulk it is the common practice to locate the propelling machinery in the aft end. This also applies to several other types of vessels for carrying other material such as ore, coal, grain, etc. The location of the propelling machinery in the aft end of the vessel of this type accounts for relatively high stresses in the vessels plating under sagging conditions or when the vessel is in the hollow of a wave; the deck plating being in compression and the bottom plating being in tension.

The so-called longitudinal system of framing, in common use, especially as applied to bottom plating, where the highest stresses place the plating in tension, does not provide adequate strength at the bulkheads at which points there is a concentration of stresses at the ends of the longitudinal framing where their continuity is destroyed by being cut at the bulkheads. This fault has been in the past inadequately remedied by providing brackets connecting the longitudinal to the transverse bulkheads, but such construction has failed to relieve'the concentrated stresses unloaded on the plating at the ends of the longitudinals due to being eccentric the longitudinals with the result of`local fractures in the shell plating and overstressed and leaky shell rivets at this point and in the bulkhead also due to the eccentric disposition and working of the brackets.

It has also been suggested to overcome the weakness caused by discontinuity of longitudinal framing by fitting doublings to the outside plating in the vicinity of the bulkheads. In some cases the Weight of such doublings has amounted to over 20% of the weight of the bulkhead.

Another weakness in the structure of vessels is attributed to the common method of fastening the bulkheads to the shell. This is particularly serious with respect to the fastening of a watertight transverse bulkhead when in combination with discontinuous longitudinals adjacent the bulkheads. When computing the strength of a vssel allowance must be made for the rivet holes punched in the plating, as the holes for the rivets which fasten .the bulkheads are invariably in about the same plane, athwart the vessel, the longitudinal strength at the bulkheads is greatly weakened as compared to the structure intermediate the bulkheads.

The so-called transverse system of framing is the oldest and still the one in most general use considering all classes of vessels, but is not now in common use in bulk cargo carriers with machinery located aft, except perhaps for moderate size vessels, because prior to my invention no adequate method has been employed to eifect the stiffening of the deck plating to resist compression forces or stresses in the fore and aft direction. Rather than increase the thickness of the plating sufliciently to resist the compression stresses without buckling I preferably provide longitudinal stiffening members to the deck plating so as not to unduly increase the weight of the vessel which would otherwise occur were the thickness of the deck plating increased to meet the compression stresses imposed under service conditions.

It is the object of my invention to eliminate the aforementioned weaknesses in the structures of a vessel.

Another object of my invention is to provide continuity in the longitudinal framing of a vessel.

A further object of my invention is to provide a form of bulkhead structure of great stiffness and which can be fastened to the shell plating without impairment to the longitudinal strength of the vessel.

A still further object of my invention is to provide a novel means of fastening common or plain bulkheads to the shell plating, without impairment of longitudinal strength.

Another object of my invention is to provide a vessel structure wherein the frame members, which are not bracketed, and beam members are stiiened intermediate their ends so that their resistance to bending stresses is equal to that of corresponding members lwhich are bracketed.

Another object of my invention is to provide a continuous brace piercing water tight longitudinal bulkheads and extending from side to side. of a vessel.

The novel features will be more fully understood from the following description and claims taken with the drawings, in which Fig. 1 represents a diagrammatic side view of a bulk liquid carrying vessel to illustrate the relationship between its various compartments.

Fig. 2 is similar to Fig. 1, but in plan view, and also illustrates my forms of transverse bulkheads and continuous longtudinals.

Fig. 3 is a partial section through my recessed form of bulkhead to illustrate a method of transverse bracing.

Figs. 4 and 5 illustrate two forms of continuous longitudinal construction embodying my invention.

Fig. 6 illustrates another form of continuous longitudinal construction being an alternative o1 Fig. 4 embodying my invention.

Fig. 6a is an alternative of Fig. 6 where the longitudinal without being slotted is rove endwise through the bulkhead.

Figs. 7, 8, 9 and 10 illustrate in greater detail how the longitudinals in Figs. 4, 5 and 6 are made continuous through the bulkhead.

Fig. 11 illustrates still another form of continuous longitudinal construction embodying my 1nvention when using my recessed form of bulkhead.

Fig. 12 is a partial cross section through the shell of a vessel illustrating a method of fastening the transverse bulkhead to the plating.

Fig. 13 is a diagrammatic layout of a vessel in plan view to illustrate transverse framing and compartments constituted by plain transverse and longitudinal bulkheads.

Fig. 14 is an enlarged cross section taken on line I4-I4 in Fig. 13.

Fig. 15 is a part section of the vessel shown in Fig. 13 to illustrate the reinforcement of a transverse frame at the upper Stringer as compensation for bracket omitted at the deck.

Fig. 16 is a part section of the vessel looking aft shown in Fig. 13 to illustrate the fore an-d aft stiffening to the deck plating.

Fig. 17 is similar to Fig. 16, showing a cross view of stiffening to the deck plating intercostal between beams.

Fig. 18 is similar to Fig. 17 showing a modification of the stiffening to the deck plating wherein the beams are knocked and longitudinals continuous.

Fig. 19 is a part section of the vessel shown in Fig. 13 illustrating the connection between the continuous cross brace and the side and bulkhead framing.

Fig. 20 is a hold plan of a vessel similar to Fig. 13 but with longitudinal framing, plain longitudinal bulkheads and illustrating the recessed transverse bulkheads.

Fig. 21 is an enlarged cross section taken on line 2I-2I in Fig. 20 and also illustrates the longitudinal framing.

Fig. 22 is a part section of the vessel shown in Fig. 20 to illustrate a method of fastening the recessed transverse bulkhead to the shell plating more especially at-the sides.

Fig. 23 is a part section taken on line 23-23 in Fig. 22 illustrating one form of local stiffening means I employ for the bulkheads of the recessed type.

Fig. 24 is a partial section through a vessel illustrating another method of continuing the strength of longitudinals through the bulkhead.

Fig. 25 is a cross section taken on line 25-25 in Fig. 24.

Fig. 26 is a cross section taken on line 26--26 in' Fig. 24.

Fig. 27 is a view similar to Fig. 26 illustrating a modified method of fastening the ends of the longitudinals to each other.

Figs. 28, 29 and 30 are similar to Figs. 24, 25, and 26 respectively but illustrating still another method of continuing the strength of the longitudinals through the bulkhead. A

Fig. 28a illustrates the ends of the longitudinals secured together through the medium of plate passing through the bulkhead.

Fig. 31 is an enlarged partial cross section at the side of the recessed bulkhead shown in Fig. 20 to illustrate one of my methods of supporting an occasional longitudinal which for local reasons it may be desired to make discontinuous.

Fig. 32 is similar to Figs. 24 and 31 Where the strength of the longitudinal is carried through the bulkhead.

Fig. 33 is a cross section on line 33-33 in Fig. 31.

Fig. 34 is a longitudinal section taken horizontally through the vessel to illustrate a bulkhead structure having intermediate transverse framing with the side longitudinals supported at the ends and reinforced in the vicinity of such framing in accordance with my invention.

Fig. 34a is a part plan view of Fig. 34 showing brackets welded to the plating, longitudinal, and bulkhead bounding bar.

Fig. 35 .is similar to Fig. 34 except that it illustrates the adaptation of my continuous system of longitudinals as illustrated in Fig. 24 where the ends are xed and the reinforcement to the longitudinal omitted in the vicinity of the transverse framing, and also illustrates the spacing of the vertical stiffeners on the transverse bulkhead.

Fig. 36 is a partial cross section through a. recessed bulkhead to illustrate another of my methods of overlapping the longitudinals.

Fig. 37 is a partial cross section taken on line 37-31 in Fig. 36.

Referring to Figs. 1 and 2 of the drawings, which illustrate the prole of a single deck vessel subdivided for carrying liquid bulk cargo, wherein I is the machinery space, 2 a fuel tank, 3 indicates cargo holds, 4 a pump room, 5 a cofferdam, 6 a deep tank, and 'I a dry cargo hold. .For convenience Fig. 1 shows both plain and recessed bulkheads, 8 indicating plain bulkheads and 9 recessed bulkheads. In Figs. l and 2 there is shown three different patterns of recessed bulkhead, for convenience, it being understood that such bulkheads may be the same pattern throughout a vessel. The three patterns are merely shown conventionally in order to illustrate that various sizes of recesses may be adapted to a particular ship in accordance with the strength requirements. I indicates the bottom longitudinals, II the side longitudinals and I2 the transverse frames intermediate the bulkheads. A shelf plate I3 is preferably provided to horizontally stiffen the recessed bulkheads. While only one such shelf plate I3 is shown it is manifest that in practice the number of such plates is determined by the depth of the vessel. The numeral I4 indicates longitudinal bulkheads.

Referring to Figs. 12 and 22, I shall now describe my method of fastening the bulkheads to the shell plating and the advantages gained. The bulkheads have secured to them short lengths of boundary bars I in spaced relation so as to preferably register with the inside strakes to which they are in turn securely bolted. Thus the edge of the bulkhead at the portions intermediate the boundary bars I5, are drawn in close proximity to the outside strakes to which they are welded. The boundary bars may then be riveted and/or welded to the inside strakes or they may be removed and the free edge of the bulkhead welded to the inside strakes. In this manner the bulkhead is rendered tight and a large number of rivet holes eliminated from the structure, which would otherwise be necessary were the bulkhead xed and made fiuid tight by riveting all the way round, with a corresponding gain in longitudinal strength to the shell plating. Of equal or greater importance is the ease with which a selected number of longitudinals may be passed continuous through the bulkheads at the welded parts as at I5' Where the above said spaced boundary bars may be cut especially for the purpose.

Referring to Fig. 11, wherein I indicate a recess of the recessed type bulkhead 9, the panels of which may be formed from several plates joined together with angle connections I6 or it may be of flanged construction as indicated at I'l or in any manner well known to the art. The size of the recesses are proportioned for adequate vertical stifening and overlapping the ends of longitudinals cut at the bulkhead. One or more horizontal girders should be provided to stiften the recessed buikheads horizontally and preferably intercostally tted in the recesses. In Figs. 1 and 3, I have indicated such stilener members which are preferably welded to the recessed bulkhead.

It will be noted that with this recessed type of bulkhead the bottom edge of the bulkhead is separated into two p-lanes more or less widely separated by the force and aft panels. Therefore, although the bulkhead may be conventionally riveted to the bottom plating, the lines of rivet holes being in different planes does not impair the strength of the plating so greatly as happens in the case of ordinary construction wherein the rivet holes are disposed in a single plane, or at frames intermediate the bulkheads, l

It will also be noted that in addition to separating the lines of rivet holes lnto two planes athwart the vessel the points at which the longitudinals are cut are also separated into the same two planes. While the depth of the recesses are proportioned for adequate vertical strength they are also proportioned for suflicient overlapping of the longitudinal ends to insure continuity of strength as illustrated in Figs. 2, 36 and 37.

20' is a support for the long ends of the longitudinals cut in Way of recesses.

To further advance continuity of longitudinal strength, I overlap the longitudinals I and II. This can be in several ways. In Fig. l1 the bottom longitudinal IU is arranged at one side of the bulkhead so that it extends beyond a lateral panel into juxtaposition with one of the fore and aft panels and the end of the longitudinal is welded and/or riveted to the panel of the recess, whereas the longitudinal I0 at the other side of the bulkhead terminates at the face of another lateral panel. A joint bar I8 is welded and/or riveted to the end of the last mentioned longitudinal and alsoto the other side of said fore and aft panel. It will be noted that with a joint of this character the ends of the longitudinals are spliced together on the fore and aft panel of the bulkhead without passing through'the bulkhead. Figs. 2, 36 and 37 illustrate how the ends on longitudinals may be staggered or overlapped in adjoining recesses and thereby give the desired continuity of strength Without passing through the bulkhead when the depth of the recess is designed with this end in view. Figs. 4, 5, 6, 6a, 7, 8, 9 and 10 show my preferred methods of providing continuity of longitudinal strength in such cases where it is desirable to have the longitudinal pass through plain bulkheads, the panels constituting the recessed bulkheads, transverse framing or like structures. The longitudinal I0 is preferably of channel section having the upper flange slotted as at I9, and the edge of the bulkhead 8 is slotted as at 20 to closely t the web and bottom flange of the longitudinal, which extends through the bulkhead in way of a welded part and is spliced to the end of an aligned longi tudinal through the medium of the joint bar 2|, I may restore the full strength of the longitudinal by Welding up the slot I9 in the ilange to the bulkhead on each side or in lieu thereof I may stiften the longitudinal where it passes through the bulkhead by welding to its upper ange a plate 2|', see Fig. 5, which passes througha slot, indicated ,by broken lines I9' Fig. 9, formed in the bulkhead, and extends at a short distance at each side thereof. The adjacent' surfacesof .the

longitudinal, the bulkhead and the shell plating are welded together. The longitudinal or the joint bar which passes through the bulkhead is carefully tight welded to the edge dcnin'g the slot in the bulkhead.

In Fig. 6 I show an alternative construction. to that just described. In this latter construction the joint bar 2|y which is shown of channel section, is treated just the same as the end of the longitudinal in Fig. 5 with or without plate 2| Fig. 5.

Fig. 6a is the same as Fig. 6 except slot I9 is omitted and the bulkhead is slotted so that the piece 2l can be rove endwise through the bulkhead.

Referring noW to Figs. 24 to 30 inclusive I show another arrangement for preserving continuity of strength which construction is particularly useful at points where boundary bars occur about the transverse members. In such constructions the longitudinals terminate adjacent the toes of the boundary bars andare secured, preferably by welding, to the transverse member 3 by means of bracket plates. In Figs. 24, 25 and 26 I show bracket plates 22 of T cross section which are seam welded to the member 8 and riveted, plug welded and/or seam welded to the respective ends of the longitudinal. In Fig. 27 I show a flat bracket plate 23 which is welded to the member 8 and which is slotted as at 24 to permit of it being seam welded to the respective ends of the longitudinals. In Figs. 28, 29 and 30 I show a bracket plate 25 which is of angle cross section and is welded securely to the member 8 and to the respective ends of the longitudinals. In some cases the ends of the longitudinals are secured to a plate which passes through a slot formed in member 8 and the lower portion is welded to the boundary bars as illustrated by Fig. 28a; the plate is tight welded to the member 8. If necessary to obtain additional strength of structure I welded bracket plates 26 to the member 8 and the respective webs of the longitudinals as illustrated in Fig. 28. The brackets and/or clips are to be made of such dimensions so that together with the shell plating the section modulus at the bulkhead connection will be at least equal to the section modulus of each longitudinal taken with the plating. I prefer to weld the longitudinals to the toe of the bulkhead boundary bars and to the outer plating at the ends for a distance of about l2, and for about 6 on each side of transverses.

In Fig. 31 it will be noted that the side longitudinal II at one side of the bulkhead 9 extends beyond the mean position, indicated by the line 9', and that the longitudinal II at the other side of the bulkhead 9 terminates short of said mean position. Under this condition the brace 2l is provided and securely welded to the end of the longitudinal and the transverse panel of the bulkhead as shown. The ends of the angles are preferably welded to the toes of the boundary bars, and also the ends of the longitudinals may be secured to the bulkhead through the medium of gussets 22.

In Fig. 33 I show the bottom longitudinal I8 overlapping the fore and aft panel of the bulkhead 9 to which they are welded and I show them cut out as at 28 to clear the boundary bars 29.

In Fig. 34 I show a side longitudinal II and transverses I2 equally spaced between the bulkheads 8. The ends of the longitudinal are welded to the toes of the boundary bars. It will be noted that the ends of the longitudinals extend Cil fully up to the bulkhead and are welded to the corner boundary bars thereby receiving a greater amount of support and xity than is possible with the so-called bracketless system where the ends are purposely kept clear of the bulkhead and considered free rather than supported. Fig. 34a shows 2 brackets 26 in the plane of the plating welded to the longitudinal, bulkhead boundary bars and plating where an increase in support, xity, and continuity of strength is desirable. If the ends of the longitudinal were fully fixed, as by brackets, to the bulkhead the maximum stresses in the longitudinal as calculated by the formula WL2 I would be at the ends and at the transverses I2.

In which formula and the formulae hereinafter set forth:

LzLength of span in feet w=Unit load on span in tons per foot of span f=Unit stress I=Moment of inertia of stiffener with plating Y=Distance of neutral axis from inner edge of stiffener With the ends supported and neglecting all xity, the maximum stresses would be at the transverses I2 and would be approximately calculated by the formula WL" {I 8" or about one and one-half times as great as in the case of fully xed ends, where not more than one intermediate support is used, and approximately by WLl 6 to 7 using the end span where the span ratios are respectively I-IO--l or l-IU-ID-T and by WLz where the ratios are respectively II'l-I-I or ID-IU-lU--IO assuming the ends are supported and neglecting all fixity. The tendency of the longitudinal under uniform head load is to bend in one direction at the transverse supports and in the opposite direction between the supports. Assuming that the outward bending changes to an inward bending at points 30, which points are usually called points of contraflexure, I reinforce the longitudinal at the transverses I2, between such points, by means of a plate 3I so as to increase Y at each transverse I2 about 50%, then the stress at the transverses I2 would be approximately the same as if the ends of the longitudinal without the plates 3l were iixed by brackets to the bulkhead.

Referring to Fig. 14, frame stiffeners are indicated by 32 and bulkhead stiffeners 33 are secured to the longitudinal bulkheads 34. I also provide Stringer plates 35.

Fore and aft stiffening is provided for the deck plating in the form of bars 36. They may be continuous through or intercostal between the deck beams 3l as indicated in Figs. 18 and 17 respectively. They may be overlapped by passing through the transverse bulkheads, in a manner to that employed for the bottom longitudinals as heretofore explained. They may be of any form riveted and/or welded to the deck, my preferred form however is a fiat bar, see Fig. 16, welded in place, or before erection.

Cross braces 38, see Figs. 14 and 19 extend continuously across the vessel, piercing the longitudinal bulkheads 34 to which they are secured ,by a tight weld. The braces are preferably of I cross section and the lower anges are coped off so that its web rests on the stringers 35 to which they are welded on the sides and by plug welding. These braces are strong enough to take the total possible maximum load either as a tie or a strut. They save weight by greatly reducing the size of stringers, especially on account of being continuous from side to side of the vessel. 'Ihey also support each individual tank and help to sustain the walls thereof in the event of loading in alternate tanks.

I prefer to flt one or more web deck beams 39 in tanks exceeding 24 ft. in length and one fore and aft intercostal grder 40. Under certain conditions these web beams and girders might be omitted and the ordinary beams increased according to the width of the tanks. The stiffening on the transverse bulkhead is preferably of the same type as 33, with or without brackets at the ends.

Frame 32 instead of being bracketed to the deck beams may be clipped to the deck plate as shown at 4|, Fig. 15. This is particularly desirable in a case where deck beams are fitted only on intermediate frames. In the case where the frames 32 are bracketed to the deck beams the stress at 4I and at the stringers 35 would be approximated by the formula and at L from the upper end by the formula wL2 f1 I weld bars 3l, similar to those used with the longitudinals aforementioned, on the frames 32 between the point of inflection on either side of the stringers 35, and in this manner increase the strength in the frames, which are clipped to the deck, to at least that of the bracketed frames.

In the structure illustrated in Fig. 35 I provide continuity tothe longitudinals Il by the use of my joint illustrated in Fig. 28a. The transverse bulkhead 8 is stlffened between the longitudinal bulkhead 9 and the side wall of the ship by means of vertical stiifeners 33 and horizontal stifeners Il', the latter being similar to the longitudinais Il. It will be noted that the vertical stiffeners are aligned with bottom longitudinals and the horizontal stlffeners are aligned with side longitudinals, the number of such stiffeners depending upon the depth and width of the hold. It is important that the distance from the longitudinal bulkhead to the adjacent vertical stiffener be approximately equal to the distance between such stiffeners; the distance between the side wall of the ship and the adjacent vertical stiffener varying according to the width of the hold. l

Referring now to Figs. 36 and 37 I have devised a structure wherein I use a recessed bulkhead and by a unique proportioning of the recesses and arrangement of the longitudinals I obtain great longitudinal strength without continuing the longitudinals through the bulkhead or overlapping longitudinal I on the fore and aft panels as above illustrated in connection with Fig. 1l. In this structure it will be noted that a1- ternate pairs of longitudinals extended to alternate transverse panels, respectively, and that their respective planes of juxtaposition are substantially spaced longitudinally of the vessel. In this manner half the joints between the aligned longitudinals are in one transverse plane and the other half are in a different plane. In each of these two planes 1/2 the longitudinals are intact and 1/2 the rivet holes punched in the plating are saved. With this construction I may also obtain continuity of the aligned longitudinals by using any of the methods described above for such purpose, in which case my preferred method being that illustrated by Figs. 24, 28 or 28a. While I have illustrated an embodiment of my invention by disposing VZ the joints in one plane and the other 1/ in another plane it is manifest that I am not limited to those proportions, but that great longitudinal strength can be obtained, compared to prior practices, by having more or less joints in one or the other planes. If the design is such that three longitudinals may be spaced in a recess I may deem it preferable to continue the middle one, through the bulkhead as in Figs. 5-6 or 6a.

In case it is necessary to provide for drainage through the longitudinals, I may do so by means of slots 20, see Fig. 34, the edges of which are securely Welded to the shell plating.

From the foregoing description it will be easily seen that I have a novel method of ship construction which is economical and particularly remedies defects which are inherent in prior methods of constructing a vessel in accordance with the so-called longitudinal or transverse framing systems. I do not Wish it to be understood that my above described methods are limited in their application to vessels of the latter construction and it is manifest that certain of the structure are useful in connection with other Well-known types of ship construction. i

The terms and expressions which I have 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 I claim as new and desire to secure by Letters Patent, is:

l. A ship having a wall and a bulkhead, said bulkhead being comprised of a pair of panels disposed in different planes, and a connecting panel disposed angularly to the pair of panels first mentioned, means to secure the bulkhead to said wall, and a pair of longitudinal members having their ends in overlapping relation extending one at each side of and secured to said connecting panel.

2. A ship having a Wall and a bulkhead, said bulkhead being comprised of a first panel secured to the wall, a second panel spaced laterally of the first panel and connected thereto by a third panel, a longitudinal member secured to saidwail with an end terminating short of the first panel, and a second longitudinal member secured to said Wall terminating short of the second panel and extending along and secured to the third panel.

3. A ship having a wall and a bulkhead, said bulkhead being comprised of a first panel secured to the wall, a second panel spaced laterally of the first panel and connected thereto by a third panel, a longitudinal member secured to said wall with an end terminating short of the first panel, a second longitudinal member secured to said Wall terminating short of the second panel and extending along and secured to the third panel, and a bracket member connecting the second panel to the first mentioned longitudinal.

4. A ship having a wall and a bulkhead, said bulkhead being comprised of a first panel secured to the Wall, a second panel spaced laterally of the first panel and connected thereto by a third panel, a pair of longitudinals secured to the wall and terminating at each side of the first panel respectively, a second pair of longitudinals having ends in overlapped relation extending along and secured to the third pane1,and a bracket member securing one of the first mentioned longitudinal members to the second panel.

5. A ship having a wall and a bulkhead, said bulkhead being comprised of a first panel, a second panel spaced laterally of the first panel and connected thereto by a third panel, a bar securing the first panel to said Wall, a longitudinal member secured to the Wall and welded to said bar, and a pair of longitudinal members having ends in overlapped relation and secured to the third panel.

6. A ship having-a Wall, a bulkhead comprised of a pair of laterally spaced transverse panels and apair of longitudinal panels,a pair of longitudinal members at one side of the bulkhead, one of which extends beyond the other and is secured to one of thelongitudinal panels,a second pair of longitudinal members at the other side of the bulkhead, one of which extends beyond the other and is secured to the other of said longitudinal panels, a joint bar securing the shorter of the iirst mentioned pair of longitudinal members to the second mentioned longitudinal panel, and a joint bar securing the shorter of the second mentioned pair of longitudinal members to the first mentioned longitudinal panel.

7. A ship having a wall, a. bulkhead comprised of a series of longitudinal panels and a series of transverse panels, said panels being angularly connected to constitute a pair of reversed recesses, a longitudinal member secured to said wall at one side of the bulkhead projecting within one of said recesses and terminating short of the transverse panel of that recess, and a longitudinal member at the other side of the bulkhead secured to said wall and projecting within the adjacent recess and terminating short of the transverse panel of that recess.

8. A ship having a wall, a bulkhead comprised of a series of longitudinal panels and a series of transverse panels, said panels being angularly connected to constitute a pair of reversed recesses, a plurality of longitudinal members extending within one recess, and a plurality of longitudinals extending with the other recess, a plurality of longitudinals aligned with the aforementioned longitudinals at opposite sides of the bulkhead respectively and means securing each of said longitudinals to the bulkhead.

HUGO P. FREAR.

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