US3611968A

US3611968A - Watertight floating boxes for underwater work on floating bodies

Info

Publication number: US3611968A
Application number: US856320A
Authority: US
Inventors: Isoe Takezawa
Original assignee: Mitsubishi Heavy Industries Ltd
Current assignee: Mitsubishi Heavy Industries Ltd
Priority date: 1968-09-12
Filing date: 1969-09-09
Publication date: 1971-10-12
Anticipated expiration: 1988-10-12

Abstract

A watertight floating box, for use in working on floating bodies such as ship sections or the like to be assembled, disassembled, repaired, or maintained while afloat comprises caisson means arranged to embrace, in watertight manner, the underwater portions of the floating body and arranged to be pumped free of water to provide a dry working space along the underwater portions of the floating body. The caisson means includes a bottom structure to extend horizontally and transversely across the bottom of the floating body and sidewall structures extending substantially vertically upwardly in facing relation with the sidewalls of the body. The sidewall structures are arranged for adjustment relative to each other transversely of the floating body in accordance with the beam or width of the floating body.

Description

United States Patent [72] Inventor IsoeTakezawa Nagasaki, Japan [21] Appl. No. 856,320 [22] Filed Sept. 9, 1969 [45] Patented [73] Assignee [54] WATERTIGHT FLOATING BOXES FOR UNDERWATER WORK ON FLOATING BODIES 7 Claims, 14 Drawing Figs.

521 vs. c1 114 77 R, 61/68, 114/46, 114/65 R 51 1111.01 B63b 3/02 501 Field of Search 1 14/77, 72, 65, 44-50, 52, 53, 43.5 R, 43.5 s; 61/64-68, s 1413; 9/6

[56] References Cited UNITED STATES PATENTS 3,416,481 12/1968 Taylor 114/77 R 808,638 l/1906 Cunningham 61/68 932,719 8/1909 Reinhardt 61/68 1,632,491 6/1927 Matthiessen et al. 114/46 3,370,565 2/1968 Takezawa et al7 114/77 Primary Examiner-Milton Buchler Assistant Examiner-F. K. Yee Attorney-McGlew & Toren ABSTRACT: A watertight floating box, for use in working on floating bodies such asiship sections or the like to be assembled, disassembled, repaired, or maintained while afloat comprises caisson means arranged to embrace, in watertight manner, the underwater portions of the floating body and arranged to be pumped free of water to provide a dry working space along the underwater portions of the floating body. The caisson means includes a bottom structure to extend horizontally and transversely across the bottom of the floating body and sidewall structures extending substantially vertically upwardly in facing relation with the sidewalls of the body. The sidewall structures are arranged for adjustment relative to each other transversely of the floating body in accordance with the beam or width of the floating body.

PATENTED 0m 1 219m SHEET 1 OF 5 mill/IA ll/I FIG.7

FIG.8

INVENTOR lsoe Tokezowo ATTORNEYS PATENTED 0m 2m:

SHEET 3 BF 5 lNVE'NTOR Isoe Tokezowo FIG.9

ATTORNEYS WATERTIGHT FLOATING BOXES FOR UNDERWATER WORK ON FLOATING BODIES BACKGROUND OF THE INVENTION Due to rapid strides, both economically and technically, made by the ship building industry, there has been a demand for ships as large as 300,000 to 500,000 d.w.t. However, most of the existing shipways or like facilities in Japan and other parts of the world are not large enough to permit construction or repairs of such huge ships. While, needless to say, such construction or repairs will be possible if shipways are expanded or sufficiently large clocks are built, this would result in an enormous expense and a great deal of time. Additionally, and sometimes, geographical conditions may not warrant such alteration of shipways or docks.

For these reasons, a so-called uniting-afloat" method has been proposed, by which a hull is built in two or more sections, these sections are separately launched, and the sections are then united while afloat. The method involves knotty problems. As it is quite natural that the divided sections are partly submerged by their own weight or displacement, the parts under water must be united safely with adequate reliability and adequate structural strength.

A suggestion for solving this problem is that the parts to be united be hermetically covered with a boxlike structure, such as a caisson, which is U-shaped in cross section, and that water then be pumped out from this structure to provide a dry space for workers to effect the necessary operations to unite the split or separate sections of the hulls.

Existing U-shaped watertight floating boxes, however, are constructed with particular widths predetermined to fit particular vessels to be handled. These fixed width boxes can be used thereafter repeatedly for ships of the same width or beam, but not for ships of other widths or beams. It is inconvenient and uneconomical to provide a number of boxes of different sizes when a number of ships of different beam are to be built.

SUMMARY OF THE INVENTION This invention relates to a watertight floating box for working on the underwater sections of a ship or a large floating object, such as a floating dock, wherein the ship or the large floating object is constructed on existing shipways or like facilities in two or more sections, separately launched, and then united while afloat into a unitary construction. More particularly, the present invention is directed to such a floating box which is adjustable in width to accommodate ships or other floating structures having various widths and beams.

The purpose of the present invention is to eliminate the drawbacks of conventional watertight floating boxes and to provide a watertight floating box of novel design and construction which can be used with vessels differing in length and beam. In accordance with the invention, either one or both of the sidewalls of a watertight floating box, in the form of a caisson or the like and U-shaped in cross section, are arranged to be shiftable relative to each other so that the box can be adjusted to the width or the beam of the ship or other floating object on which work is to be performed.

An object of the invention is to provide an improved water tight floating box for working on underwater portions of a floating body, such as a ship hull or the like.

Another object of the invention is to provide such watertight floating box which is adjustable for fitting on the hulls of ships or other floating bodies of different beams or widths.

A further object of the invention is to provide such a watertight floating box including sidewalls which are adjustable relative to each other laterally of the floating body to accommodate floating bodies of different widths or beams.

Another object of the invention is to provide such a floating box which is simple and inexpensive in construction and efficient in operation.

For an understanding of the principles of the invention reference is made to the following description of typical embodiments thereof, as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of a watertight floating box, embodying the invention, as fixed to the hull of a ship;

FIG. 2 is a transverse sectional view corresponding to FIG.

FIG. 3 is a top plan view of the watertight floating box;

FIG. 4 is a sectional view taken on the line IV-IV of FIG. 3;

FIG. 5 is a sectional view taken on the V-V of FIG. 4;

FIG. 6 is a perspective view of a movable sidewall of the watertight floating box;

FIGS. 7 and 8 are transverse sectional views of waterproof packings having difierent cross sections;

FIG. 9 is a side elevation view of means insuring watertightness of the floating box against the bilge curves of a ship hull;

FIG. 10 is a sectional view taken on the line X-X of FIG. 9;

FIG. 11 is a plan view of another embodiment of watertight floating box in accordance with the invention;

FIG. 12 is a sectional view taken on the line XII-XII of FIG. 11;

FIG. 13 is a sectional view taken on the line XIIIXIII of FIG. 12; and

FIG. 14 is a sectional view taken on the line XIV-XlV of FIG. 12.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In each of FIGS. I through 10, reference numeral 1 indicates a ship hull in the form of two or more sections, such as the sections 1 and 1", built on existing shipways of relatively small size, launched, and to be united while afloat. A watertight floating box 2, in accordance with the present invention, is a U-shaped caisson whose inner dimensions are greater than the external dimensions of the sections 1 and 1" of hull l to be united, and box 2 has a plurality of ballast tanks 3. Water is pumped into or out of ballast tanks 3 so that box 2 may have its buoyancy or trim adjusted in a manner similar to that of a small floating dock.

Watertight floating box 2 generally comprises a bottom structure 4 that extends horizontally and transversely along the bottom of hull 1, and

sidewalls

5 and 6 at opposite ends of bottom structure 4 and facing the outside plating of the hull. Sidewall 5 is movable over bottom structure 4 transversely of the ship resting on such bottom structure.

Sidewalls

5 and 6 are formed with curved portions 8 and 9, respectively, along the bilge curves of hull l and portions 8 and 9 have curvatures that conform snuggle to these curves so that, when sidewall 5 is drawn fully up to the side of hull l which it faces, the entire inner faces of

sidewalls

5 and 6 are in contact with the side strakes of the vessel.

In the central portion of the watertight floating box 2, over bottom structure 4 and between

sidewall structures

5 and 6, an operating space is provided as indicated in FIG. 5, and is high enough and wide enough for workers to perform their functions while standing erect.

Movable sidewall 5 is maintained upright by means of guide means 11 extending from both sides of its lower end and fitting in guide channels 12 formed in bottom structure 4. The front end portions 13 of sidewall 5, as best seen in FIG. 6, extend a certain distance transversely of the ship into hollow tanks 14 provided in bottom structure 4, and afford a continuous surface opposite the bottom of the ship hull and irrespective of the movement of sidewall 5.

A pair of threaded rods 15, which extend horizontally through sidewall 5, are driven by a motor 19 through worm gears 17 and worms l8. Rods 15 are supported at opposite ends by thrust bearings 16 mounted on bottom structure 4. Holes are provided in sidewall 5 through which threaded rods 15 extend, and these holes are internally threaded for engagement with the rods so that rotation of the rods will effect movement of sidewall 5, as a whole, transversely of the ship and over bottom structure 4. Alternatively, rods 15 can be mounted in sidewall 5 and threadly engage through nuts in bottom structure 43.

Watertight box 2 is provided with watertight packings 21 where it faces the outside plating of the vessel hull, and these packings extend from sidewall 6 along bottom structure 4 and up sidewall 5. The cross section of the watertight packings may be that of sheet rubber or strip rubber, as shown in FIG. 7, or of a rubber tube shape, as shown in FIG. 8 and which expands when supplied with compressed air or the like. In short, any kind of packing may be used provided it will not permit water to leak between the outside plating of the vessel and the interior of the watertight floating box, and provide the working space 10 therebetween. Packings 21 are fixed immovably on sidewall 6 and on bottom structure 4, but are fitted slidably on sidewall 5 so as not to hinder adjustment thereof. The free ends 22 of the packings 21 can be pulled up with wires 23, from the deck of the ship, and in accordance with the movement of sidewall 5.

FIGS. 9 and 10 illustrate another embodiment of the invention, wherein the bilge curves are tightly sealed against water. Today, in designing tankers or the like as large as 300,000 to 500,000 d.w.t., it is the practice to form bilge curves substantially of the same radius of curvature and regardless of the size of the vessel. Nevertheless, and due to reasons such as convenience in designing or technical errors, the bilge curves do not always fit completely with the curved portions 8 and 9 of the sidewalls of the watertight floating box. As a matter of fact, in certain cases there is a quite considerable gap resulting. In such a case, if the gap is such that it can be compensated by elastic deformation of packings 21, there if no problem. However, if the gap is larger than can be compensated, the bilge curves are no longer watertight.

In view of this possibility, slide packings 25 may be provided to be displaceable through a certain distance with respect to the hull by means of hydraulic cylinders 24 or the like. Slide packings 25 are fitted in guide grooves for the

sidewalls

5 and 6, in such a manner that, when they are pressed by hydraulic cylinders 24 against the hull, they are deformed at their front faces into close contact with the hull surface, and at both sides into close contact with the guide grooves.

Since water can leak through the portions of sidewall 5 and bottom structure 4 in slidable contact, it is desirable further to provide, although not shown, watertight packings such as rubber tubes along those portions so that, after movement of sidewall 5 into position, the rubber tubes or the like may be inflated with compressed air to ensure watertightness therealong.

Water that has unavoidably leaked into the working space 10 of watertight floating box 2 can be collected in a low place and pumped out. Thus, as long as a leakage is kept below the capacity of the drain pump, the box of the above invention will efficiently serve its purpose.

In order that they can be united while afloat, two sections of a ship hull, separately built on and launched from existing shipways or the like, such as the forebody l and the afterbody ll", are positioned as shown in FIG. 1 to proper trim and draft, as by adjustments of water ballasts in the internal ballast tanks. Then, with the help of tugboats or cranes, watertight floating box 2 is brought immediately in front of or astern of the hull.

Next, ballast tanks 3 inside box 2 are suitably filled with water until the box has a desired displacement in the water. The box is then towed longitudinally of the ship hull by a tugboat to a point beneath the parts to be united. Needless to say, sidewall 5 of box 2 is adjusted beforehand so that the box has a somewhat greater interior width than the beam of the hull. In this state, water in ballast tanks 3 inside box 2 is gradually drained, while the box is pushed by the tugboat toward the outside plating of the hull until it comes into close contact therewith. Box 2 then floats up and the upper surface of bottom structure 4 will be pressed against the bottom plating of the hull, with the interposition of packings 2i. Thereupon,

movable sidewall 5 is moved by motor 19 toward the hull and forced into close contact with the outside plating of the hull, again with the interposition of packings 21.

In this embodiment of the invention, it is desirable to pull up the free ends 22 of packings 21 with wires 23, from the deck and while sidewall 5 is being moved. When the above operation is completed, rubber tubes (not shown) which are provided along the movable sidewall 5 and the bottom structure 4 in slidable contact are supplied with compressed air to establish a seal along these portions. Similarly, when rubber tube packings are employed as packings 21 between watertight floating box 2 and the hull, these rubber tubes also are inflated with compressed air to ensure a perfect sealing effect along the hull portions. Inasmuch as working space 10 of box 2 is thus isolated in a watertight manner from the surrounding water, it is only necessary to pump out water, if any, from space 10, so as to provide a dry working space wherein workers can safely perform the operations of uniting the hull sections.

Another embodiment of the watertight floating box is shown in FIGS. 11 through 14. This embodiment of the inven' tion includes a separate fixed supporting wall 27 outside moveable sidewall 5, and which is capable of moving sidewall 5 toward or away from the opposing side of the hull through the medium of hydraulic actuated means 28 installed in supporting wall 27. The portions of sidewall 5' and bottom structure 4 which slidably fit each other are in the form of a dish that has tapered sidewalls 29 and a mating filler, as shown in FIG. 13, and the bottom of movable sidewall 5 is covered all over with a packing sheet 30. Supporting wall 27 is fastened with bolts 31 to bottom structure 4, in a position adjustable to some extent in accordance with the size of the vessel.

Movable sidewall 5 is also equipped with ballast tanks 32, which can be drained at the time of movement so the sidewall 5' can gain suitable buoyancy and lessen its friction with bottom structure 4'. Guide structures 33 serve to keep sidewall 5 from separating to too great an extent from bottom structure 4' during movement.

A watertight floating box built in this way is relatively simple in construction. Moreover, the front ends 34 of sidewall 5' act like wedges between hull 1 and bottom structure 4 as sidewall 5' is pressed against hull 1, thus enhancing the watertight effect for both hull 1 and bottom structure 4.

Some embodiments of the watertight floating box of the invention and the practical use of the box in uniting floating hull sections, have been described. The box, of course, is useful not only when ship sections are united when afloat but also when a ship or a floating object is divided or repaired while afloat, and the box may have still other applications. Thus, if the box is moved gradually longitudinally of the ship or a floating body, nearly the entire part of the floating body under water can be repaired, inspected, painted and otherwise treated. Thereby, dry docks which have hitherto been regarded as indispensable for this type of operation, can be dispensed with.

The means for moving sidewall 5 may comprise a winch, wire, crane or the like. In short, when a ship or a floating object is to be united, divided, or repaired, those parts under water to be so treated are hermetically sealed against water by means of a caisson or the like, and water is pumped out of the inside of the box to provide a dry working place where workers can perform their duties. In the watertight floating box embodying the invention, at least one of the sidewalls is movable with respect to the side of the ship or other floating body, and the box is thus made adjustable with which to match the beam of the ship or floating object. In this manner, one size of watertight floating box can be used for ships of various different beams.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A watertight floating box, for use in working on floating bodies such as ship sections or the like to be assembled, disassembled, repaired, or maintained while afloat, said box comprising caisson means arranged to embrace, in watertight manner, the underwater portions of the floating body upon which work is to be performed and arranged to be pumped free of water to provide a dry working space along the underwater portions of the floating body; said caisson means comprising a bottom structure to extend horizontally and transversely across the bottom of the floating body, and sidewall structures extending substantially vertically upwardly in facing relation with the sidewalls of the floating body; said sidewall structures being mounted for adjustment relative to each other transversely of the floating body in accordance with the beam or width of the floating body; one of said sidewall structures being fixed relative to said bottom structure; the other sidewall structure being adjustably mounted on said bottom structure for adjustment toward and away from said fixed sidewall structure; and actuator means operatively engaged between said bottom structure and said movable sidewall structure to adjust said movable sidewall structure relative to said fixed sidewall structure.

2. A watertight floating box, as claimed in claim 1, in which said actuator means includes a screw rotatably mounted in one of said bottom structure and said movable sidewall structure and a nut fixed in the other thereof and engaged with said screw; and driving means operable to rotate said screws.

3. A watertight floating box, as claimed in claim 1, including hydraulic actuator means engaged between said bottom structure and said movable sidewall structure to adjust said movable sidewall structure relative to said fixed sidewall structure.

4. A watertight floating box, as claimed in claim 1, in which said movable sidewall structure and said bottom structure are telescopically interengaged.

5. A watertight floating box, as claimed, in claim 1, in which said bottom and sidewall structures are provided with sealing gaskets extending along their surfaces engageable with the floating body.

6. A watertight floating box, as claimed in claim 5, in which said gaskets are inflatable tubular gaskets.

7. A watertight floating box, as claimed in claim 1, in which said movable sidewall structure is slidably engaged with said bottom structure; and inflatable and deflatable sealing gaskets interposed between the slidably engaged parts of said movable sidewall structure and said bottom structure.