JPS6147754B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for launching a double-skirt type marine structure in which a buoyancy section is constructed around the underside of the deck so that a hollow section having a downward opening is formed at the center under the deck, and It relates to an apparatus for carrying out the method.

Offshore structures such as oil drilling rigs that have a hollow section below the deck with an opening at the bottom have a large draft. Therefore, even if an attempt is made to launch such an offshore structure using the existing dock, sufficient buoyancy will not be generated, making it difficult to launch.
Therefore, several methods have been proposed for launching such marine structures. First, one method is to construct a dock deeper than the draft of the marine structure, and after constructing the marine structure there, float it and launch it. Other methods include attaching a buoyancy tank for launching to an offshore structure to increase its buoyancy, or constructing an offshore structure on a barge and launching it using the buoyancy of the barge.

However, the former method requires a huge amount of cost for the construction of the dock, and the latter method also requires a large amount of cost, as well as the removal of the launching buoyancy tank or barge. During this process, the offshore structure behaves unstable and is dangerous.In addition, a large number of jigs are required to attach the offshore structure to the buoyancy tank for launching and to the barge, and the work of attaching and detaching it requires a lot of work. The disadvantage is that it requires a lot of manpower.

The present invention solves the above-mentioned conventional drawbacks,
For double-skirt marine structures that have a buoyancy section around the underside of the deck, with a hollow section with an opening at the bottom formed in the center below the deck, the opening is closed with a blind plate and the hollow section is used as a buoyancy chamber. It is an object of the present invention to provide a method for launching a marine structure, thereby reducing the draft of the marine structure so that the marine structure can be launched even from existing docks, and an apparatus for implementing this method.

One aspect of the present invention is a method for launching a double-skirt type marine structure in which a buoyancy section is configured around the under-deck so that a hollow section having an opening at the bottom is formed at the center under the deck, This is an invention of a method for surfacing and launching a marine structure by injecting water into the dock after blocking the dock, and another invention is an invention of an apparatus directly used for carrying out the invention of the method. , this device is a launching device for the above-mentioned marine structure, in which a gasket is provided around a blind plate for closing the opening, and a water injection valve and a buoyancy tank capable of filling and discharging water are further attached to the blind plate. It is made up of things.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, 1 is a deck 4 so as to form a hollow part 3 having an opening 2 at the bottom in the center of the lower part of the deck 4.
It is a double-skirt marine structure with a buoyancy section 5 around its lower periphery. In FIG. 2, 6 is a blind plate for closing the opening 2 of the marine structure 1, and a gasket 7 is provided around the blind plate 6 to seal the gap between the blind plate 6 and the opening 2. Furthermore, when removing the blind plate 6 from the opening 2, a water injection valve 8 is used to inject water into the buoyancy chamber 3' formed in the hollow part 3.
and a buoyancy tank 9 used for floating and recovering the blind plate 6 are attached to the blind plate 6, and a buoy 10 used for displaying the sinking position is connected to the buoyancy tank 9 as necessary, and the launching device 11 of the present invention is installed. Configure. Here, the size and shape of the blind plate 6 corresponds to the opening 2 of the bottom 12 of the marine structure 1, and is formed slightly larger than the opening 2. The gasket 7 is provided at a portion where the blind plate 6 contacts the opening 2. The water injection valve 8 is composed of a valve 13 and a pipe 14.
is attached to the blind plate 6 so that the pipe 14 passes through the blind plate 6 downward. As the buoyancy tank 9, a tank having a volume sufficient to float and recover the blind plate 6 is used. The buoy 10 is a hollow ball and is attached to the buoyancy tank 9. The buoy 10 and the buoyancy tank 9 may be connected by a flexible hose 15 so that compressed air can be sent into the buoyancy tank 9 via the buoy 10, or the flexible hose 15 may be provided separately. A drain pipe 16 is attached to the buoyancy tank 9 so that the water contained in the buoyancy tank 9 can be discharged by compressed air sent through a flexible hose 15.

The launching device 11 configured as described above is placed below the marine structure 1, or the marine structure is built on top of it, and the wires 18 are hung from a plurality of winches 17 installed on the deck 4 of the marine structure 1. , the wire 1
The tip of 8 is connected to the launching device 11 and brought into close contact with the opening 2 of the bottom 12 of the marine structure 1. Then, the inner peripheral surface 19 of the hollow part 3 of the marine structure 1 and the launching device 11
A plurality of turnbuckles 21 are attached between the reinforcing member 20 attached to the launching device 11 so as to cover the opening 2 of the bottom 12 of the marine structure 1. Install and fix to ensure sufficient watertightness.

Next, when water is poured into the dock 22, the opening 2 in the bottom 12 of the marine structure 1 is closed, the hollow part 3 becomes a buoyancy chamber 3', and water pressure acts on the blind plate 6, making the packing watertight. The marine structure is capable of floating even at conventional depths. If offshore structure 1 surfaces, dock 2
2 (not shown) is opened, the marine structure 1 is pulled out of the dock 22 by the support vessel 23, and the marine structure 1 is towed offshore to a sufficiently deep water area or to its work area. When arriving at the sea area, the offshore structure 1 is stopped at a predetermined position, and the turnbuckle 2 is moved.
1 is loosened, the turnbuckle 21 and other accessories are removed, and the marine structure is completed. Next, when the water injection valve 8 is opened and the seawater below is introduced into the buoyancy chamber 3' of the marine structure 1, the buoyancy tank 9 is also filled with water. Once an appropriate amount of water has been injected into the buoyancy chamber 3', the winch 17 on the deck 4 of the marine structure 1 is operated to loosen the wire 18, and the launching device 11 sinks downward due to the dead weight of the blind plate. do. When the launching device 11 has descended to a predetermined position, the wire 18 is connected to the launching device 1.
Remove from 1. The launching device 11 leaves the wire 18, the position of which is indicated by the buoy 10.

Next, the offshore structure 1 is towed by the support ship 23 and shifted from above the launching device 11 to the side. Next, the flexible hose 15 is extended from the compressor 24 provided on the support ship 23, and the tip of the flexible hose 15 is extended. Compressed air is delivered to the buoyancy tank 9 via the flexible hose 15 of the buoy 10 or a single flexible hose. The water in the buoyancy tank 9 is discharged through the drain pipe 16 by compressed air, and as a result, the buoyancy tank 9 generates a buoyant force greater than its own weight, and the launching device 1
1 floats to the surface. The floating launching device 11 is recovered by a barge using a crane ship or towed by a support ship 23 and brought back, and lifted using a crane on a quay and recovered to the ground.

As explained above, the present invention has the effect of being able to easily launch offshore structures with large drafts using existing docks, and reducing the cost of steel materials and other related expenses. Additionally, the launching device can be recovered and used repeatedly.

[Brief explanation of the drawing]

Figure 1 is an overall explanatory diagram showing the state in which the launching device is attached to the marine structure in the dock, Figure 2 is an explanatory diagram of the main part showing the state in which the launching device is attached to the marine structure, and Figure 3 is Figure 2 is an enlarged view of part A, Figure 4 is an explanatory diagram showing the state in which the launching device is lowered at sea, Figure 5
The figure is an explanatory diagram showing a state in which compressed air is sent to the launching device to cause it to float. 1... Marine structure, 2... Opening, 3... Hollow part, 4... Deck, 5... Buoyancy part, 6... Blind plate, 7
...Putskin, 8...Water injection valve, 9...Buoyancy tank, 10...Buoy, 11...Water cutoff device.

Claims (1)

[Scope of Claims] 1. A method for launching a double-skirt marine structure in which a buoyancy section is constructed around the underside of the deck so that a hollow section having an opening at the bottom is formed at the center under the deck, comprising: A method for launching a marine structure, which comprises: blocking the dock, and then injecting water into the dock to float the marine structure and launch it. 2. A launching device for a double-skirt type marine structure in which a buoyant part is constructed around the underside of the deck so that a hollow part with an opening at the bottom is formed in the center under the deck, and a blind for closing the opening. A launching device for a marine structure, characterized in that a seal is provided around the board, and a water injection valve and a buoyancy tank capable of filling water and water are attached to the blind board.