GB2143783A

GB2143783A - Bulkhead

Info

Publication number: GB2143783A
Application number: GB08416562A
Authority: GB
Inventors: Seiichiro Murata; Masarus Tateishi; Toshio Yoshioka; Sakito Kamei; Hiroshi Nakazono; Yoshiro Yamawaki; Tohru Hori; Yoshitada Hiramatsu; Eiichi Sato; Yasuhiro Imai
Original assignee: Hitachi Zosen Corp
Current assignee: Hitachi Zosen Corp
Priority date: 1983-07-22
Filing date: 1984-06-29
Publication date: 1985-02-20
Also published as: SE8403807D0; GB8416562D0; DK351784A; FI842757A; FI79269C; ES8507401A1; KR890003114Y1; FI842757A0; FI79269B; SE8403807L; IT1177917B; NL8402294A; GB2143783B; NO166074B; DK161065B; FR2549440B1; NO842949L; NO166074C; KR850009563U; SG62487G

Abstract

A ship with a double shell structure comprising an inner hull plating and an outer hull plating 2 connected together only by a plurality of connecting longitudinals 3 fixed to transverse bulkheads 4 spaced apart longitudinally of the ship except by the transverse bulkheads, each of the transverse bulkheads having a double shell structure 11 at least at a peripheral portion thereof. <IMAGE>

Description

SPECIFICATION Transless ship The present invention relates to a transless ship, and more particularly to a structure for tankers and like cargo ships.

With a navigating tanker, various forces act on the hull. For example, the hull itself is subjected to a longitudinal bending moment and torsional forces, the outer bottom plating and the outer side plating to the pressure of water, and the inner bottom plating and side wall of the hold (oil tank) to the load of oil cargo under gravity. To withstand these forces, the hull includes a large number of structural members such as longitudinal (side longitudinals, bottom longitudinals, central girder, etc.) extending longitudinally of the ship and transverses (side transverses, botto m transverses, etc.) provided transversely of the ship. In the case of such a structure, however, longitudinals and transverses are provided in an intersecting arrangement, so that difficulties are encountered in building the hull by automatic work procedures (e.g. automatic welding).To assure automatic work procedures, therefore, a double shell structure has been proposed which includes no transverses other than transverse bulkheads and which comprises an inner hull plating and an outer hull plating connected together only by connecting longitudinals fixed to the transverse bulkheads except by the transverse bulkheads. In this case, however, forces acting on the inner and outer hull platings are all transmitted to the transverse bulk heads through the connecting longitudinals, so that the proposed structure has problems in respect of strength when the transverse bulkheads are of conventional structure.

An object of the present invention is to provide a transless ship having a double shell structure which comprises an inner hull plating and an outer hull plating connected together substantially only by connecting longitudinals and which can be realized without any problem of strength.

To fulfill the above object, the present invention provides a transless ship comprising at least opposite side portions and a bottom portion each having a double shell structure, the double shell structure comprising an inner hull plating and an outer hull plating connected together only by a plurality of connecting longitudinals fixed to transverse bulkheads spaced apart longitudinally ofthe ship except by the transverse bulkheads, each of the transverse bulkheads having a double shell structure at least at a peripheral portion thereof.

With the transless ship described, each transverse bulkhead has a double shell structure at least at a peripheral portion thereof, so that even when a force acting on the inner or outer hull plating is transmitted to the transverse bulkhead through the connecting longitudinals, the transverse bulkhead fully withstands the force without abnormal bending or buckling.

Further because the double shell structure has an inner hull plating and an outer hull plating which are connected together substantially by connecting longitudinals only, the transless ship has the following advantages.

(1 ) Absence of transverses decreases the number of components, while absence of intersections between the connecting longitudinals with transverses makes it possible to build the hull by automatic work procedures (e.g. automatic welding) with a greatly improved efficiency, further facilitating perfect inspection of the space defined by the inner and outer hull platings.

(2) Because the connecting longitudinals have no intersections with transverses, cracking is avoidable that would otherwise result from stress concentration at such intersections.

(3) Spaces defined by the inner and outer hull platings and divided by the connecting longitudinals only can be utilized as ballast tanks. Moreover, the ballast tank, which is not divided by transverses longitudinally of the ship drains completely with ease.

(4) Even if a flammable liquid or gas should ingress into a space between the inner and outer hull platings owing to damage to the inner plating, the liquid or gas can be easily drawn off from the space to eliminate an explosion hazard since there is no transverse dividing the space longitudinally of the ship.

(5) Absence of transverses facilitates stress analysis for the hull and assures a rational arrangement of components for a weight reduction.

(6) The double shell structure prevents outflow of cargo oil in the event of a collision with other ship or stranding.

(7) Since the hold has no inside projections such as stiffeners, the inside wall of the hold can be coated, washed or stripped efficiently and properly and is smaller in the surface area to be coated.

Various features and advantages of the present invention will become apparent from the following description of embodiments with reference to the accompanying drawings, in which: Figure 1 is a diagram in transverse section showing a transless ship according to a first embodiment of the invention; Figure2 is a diagram in section taken along the line ll-ll in Figure 1; Figure 3 is a diagram in section taken along the line Ill-Ill in Figure 1; Figure 4 is a diagrams in transverse section showing a transless ship according to a second embodiment of the invention; Figure 5 is a diagram in section taken along the line V-V in Figure 4; Figure 6 is a diagram in section taken along the line Vl-VI in Figure 4;; Figure 7 is a diagram in transverse section showing a transless ship according to a third embodiment of the invention; Figure 8 is a diagram in section taken along the line VIII-VIII in Figure 7; Figure 9 is a diagram in section taken along the line IX-IX in Figure 7; Figure 10 is a diagram in transverse section showing a transless ship according to a fourth embodiment of the invention; Figure 11 is a diagram in section taken along the lineXI-XI in Figure 10; Figure 12 is a diagram in section taken along the lineXII-XII in Figure 10; Figure 13 is a diagram in transverse section showing a transless ship according to a fifth embodiment of the invention; Figure 14 is a diagram in section taken along the line XIV-XIV in Figure 13; Figure 15 is a diagram in section taken along the line XV-XV in Figure 14;; Figure 16 is a diagram in longitudinal section of a transless ship according to a sixth embodiment of the invention; Figure 17 is a diagram in transverse section showing a trans less ship according to a seventh embodiment of the invention; Figure 18 is a diagram in section taken along the line XVIII-XVIII in Figure 17; Figure 19 is a diagram in section taken along the line XIX-XIX in Figure 17; and Figure 20 is a perspective view showing the same ship.

With reference to Figures 1 to 3 showing a first embodiment of the invention, the transless ship comprises a deck portion, a bottom portion and opposite side portions each having a double shell structure. The structure comprises an inner hull plating 1 and an outer hull plating 2 which are connected together by connecting longitudinals 3.

Additionally, the inner and outer hull platings 2,3 are interconnected by transverse bulkheads 4 (only one illustrated) which are spaced apart longitudinally of the ship. Each of the transverse bulkheads 4 has a double shell structure comprising two vertical plates 5 which are connected together by connecting members 6 extending in the direction of height of the ship. Weight reduction holes 7 and 8 are formed in the connecting longitudinals 3 and the connecting member 6, respectively.

Figures 4 to 6 show a second embodiment wherein each transverse bulkhead 4 comprises two vertical plates 5 which are connected together by connecting members 6 extending in the direction of height of the ship, and a flaring box 9 which is attached to the lower ends of the vertical plates 5. (The flaring box 5 can be regarded as a double shell structure). The flaring box 9, because of its shape, gives increased strength to the lower portion of the transverse bulkhead 4. Further because the transverse bulkhead 4 has an increased thickness at the portion of flaring box 9, the length of the connecting longitudinals 3 of the bottom portion interposed between two adjacent transverse bulkheads 4 is smaller by a corresponding amount. This leads to the advantage of giving enhanced strength to the hull .

Figures 7 to 9 show a third embodiment wherein each transverse bulkhead 4 comprises two vertical plates 5 which are connected together by connecting members 6 extending in the direction of height of the ship, and an upper flaring box 10 and a lower flaring box 9 attached respectively to the upper ends and lower ends of these vertical plates 5. The upper flaring box 10 not only produces the same effect as the lower flaring box 9 in giving increased strength but also has the advantage to be described later.

Figures 10 to 12 show a fourth embodiment wherein each transverse bulkhead 4 comprises two vertical plates 5 positioned in the center of the bulkhead 4 and connected together by connecting members 6 extending in the direction of height of the ship, and a flaring box 11 in the form of a rectangular ring and surrounding these vertical plates 5. This embodiment is more advantageous than the three foregoing embodiments in that the transverse bulkhead 4 is reinforced by the flaring box 11 at its entire peripheral portion.

According to the four embodiments described, each of the deck portion, the bottom portion and the opposite side portions has a double shell structure, but the deck portion need not always have the double shell structure. When the flaring box 11 is provided, the interior space of the box 11 can be utilized as a passage for workers or is usable for the installation of pumps, etc.

According to a fifth embodiment shown in Figures 13 to 15, the bottom portion and the opposite side portions only of the ship have a double shell structure. Each transverse bulkhead 4 comprises a vertical corrugated plate 12 in the center and a flaring box 11 in the form of a rectangular ring and surrounding the corrugated plate 12. The drawings further show reinforcing deck longitudinals 13 attached to the inner side of the outer hull plating 2, a hold 14formed between and defined by two adjacent transverse bulkheads 4, and oil or like liquid 15 loaded in the hold 14with an upper space left unoccupied.

During navigation, the ship will pitch or roll, sloshing the liquid 15 within the hold 14 and causing the liquid to strike an upper portion of the flaring box 11 of the bulkhead 4 as illustrated in Figure 15. In such an event, the liquid 15, without being restrained from further movement, moves along the slanting surface of this portion of the flaring box 11. Conse quentlythe upper corner of the hold 14 will not be subjected to a great force and can be prevented from cracking due to stress concentration. The embodiments of Figures 7 to 9 and Figures 10 to 12 also have the same advantage.

Figure 16 shows another embodiment which has the same constuction as the one shown in Figures 13 to 15 except that the deck portion of the ship, like other portions thereof, has a double shell structure including inner and outer hull platings 1 and 2.

Figures 17 to 20 show another embodiment wherein each transverse bulkhead 4 comprises a generally rectangular central corrugated plate 12' having four curved corners 1 2a', and a flaring box 11' in the form of a generally rectangular ring and having four curved corners 11 a' which are in conformitt with the shape of the corners 12a'. The four curved corners 1 la' of the flaring box 11' give still increased strength to the transverse bulkhead 4 because the forces delivered to the bulkhead 4 can be prevented from concentrating on the four courners of the bulkhead 4.

Claims

1. A transless ship comprising at least opposite side portions and a bottom portion each having a double shell structure, the double shell structure comprising an inner hull plating and an outer hull plating connected together only by a plurality of connecting longitudinals fixed to transverse bulkheads spaced apart longitudinally of the ship except by the transverse bulkheads, each of the transverse bulkheads having a double shell structure at least at a peripheral portion thereof.

2. Atransless ship as defined in claim 1 wherein each of the transverse bulkheads comprises two vertical plates connected together by connecting members extending in the direction of height of the ship.

3. Atransless ship as defined in claim 1 wherein each of the transverse bulkheads comprises two vertical plates connected together by connecting members extending in the direction of height of the ship, and a flaring box attached to the lower ends of the vertical plates.

4. Atransless ship as defined in claim 1 wherein each of the transverse bulkheads comprises two vertical plates connected together by connecting members extending in the direction of height of the ship, and an upper flaring box and a lower flaring box attached respectively to the upper and lower ends of the vertical plates.

5. A transless ship as defined in claim 1 wherein each of the transverse bulkheads comprises two vertical plates positioned in the center of the bulkhead and connected together by connecting members extending in the direction of height of the ship, and a flaring box surrounding the vertical plates.

6. A transless ship as defined in claim 1 wherein each of the transverse bulkheads comprises a central corrugated plate and a flaring box surrounding the corrugated plate.

7. A transless ship as defined in claim 6 wherein the corrugated plate is generally rectangular and has four curved corners, and the flaring box is in the form of a generally rectangular ring and having four curved corners in conformity with the shape of the curved corners.

8. A transless ship substantially as described herein with reference to, and as illustrated in, Figures 1 to3,4to6,7to9, 10-12,13-15, 16or17to 20 of the accompanying drawings.