JPH02214404A - Method of laying long member for floating plant in rising manner - Google Patents

Abstract

PURPOSE:To safely perform laying work of long member in a rising manner with high efficiency and at low cost by sinking an intermediate buoy, together with the long member, in the sea with the intermediate buoy being fixed to the long member. CONSTITUTION:A sinker chain 12 is previously secured to the bottoming point of a long member 5, then it is sunk and bottomed. An intermediate buoy 1 is fixed to an intermediate section of the long member 5 on a laying vessel. A sinker 15 for mooring the vessel is fixed through a wire 16 to the intermediate buoy 1. Then the tip of the long member 5 is secured to a floating plant 11. Then the intermediate buoy 1 and the sinker 15 are suspended by a crane 19 in a crane vessel 18 and sunken into the seal together with the long member 5. The intermediate buoy 1 floats on the sea at a predetermined position and the long member 5 is suspended in catenary. By such arrangement, fixing work of the long member 5 to the intermediate buoy 1 can be carried out easily on the sea face or on the land.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an electric cable between the seabed and a floating plant.
The present invention relates to a method for standing up and installing long bodies such as optical cables, liquid pipes, gas pipes, etc. for floating plants.

[Prior Art] Fixed and mobile floating plants such as offshore power plants, garbage incinerators, docks, crude oil storage facilities, and temporarily berthed oil tankers have systems that allow transportation from the floating plant to other locations. Or conversely, electricity, light, liquid,
In order to send and receive gas, etc., it is necessary to erect and install a long body from the seabed to the floating plant. In this case, the elongated body is provided with a catenary to prevent abnormal tension from being applied to the elongated body due to movement of the floating plant.

As shown in Fig. 4, the conventional method for erecting and installing a long body for a floating plant is to float an intermediate buoy 1 in advance by anchoring it in the sea (between the sea surface and the seabed) with an anchor chain 2 and an anchor 3. When launching the floating plant 7 from the seabed 4 to float the long body 5 on the sea surface 6, the long body 5 was first attached to the intermediate buoy 1, and then the floating plant 7 was launched (specially Publication No. 61-24893). In this case, the elongated body 5 is fixed to the intermediate buoy 1 with a gripping tool 8, and in order to prevent the elongated body 5 from abnormally bending at the intermediate buoy 1 and the flotation plant 7, a bending limiter 9 is used. intermediate buoy 1
and the floating plant 7, and the elongated body 5 was fixed to these bending limiters 9.

[Problem to be solved by the invention] However, in such a method of standing up and laying a long body,
When attaching the long body 5 to the intermediate buoy 1 floating in the sea, the installation work must be done underwater using a dipper, and if the waves are rough or the tide is fast at this time, the work efficiency is very poor. Moreover, it was dangerous and sometimes difficult to implement.

In addition, the intermediate buoy 1 is installed in the sea, for example, about 10 meters below the sea surface, in order to reduce the influence of waves and not to interfere with the navigation of ships, so it is difficult to work underwater because it is dark even during the day. The accuracy and safety of the system deteriorated, work became difficult in areas with severe seawater pollution, and lighting equipment was required for underwater work, resulting in high construction costs.

The object of the present invention is to omit the work of attaching a long body to an intermediate buoy in the sea, which is difficult and dangerous, and to perform the installation work safely and efficiently (and at low cost). An object of the present invention is to provide a method for standing up and installing a long body for a floating plant.

[Means for Solving the Problems] To explain in detail the present invention that achieves the above object, the present invention has an intermediate buoy attached to a midway portion of a long body that is raised between the seabed and a floating plant. In the method for standing up and installing a long body for a floating plant, the intermediate buoy is floated in the sea, and the long bodies serve as catenaries on both sides of the intermediate buoy. It is characterized in that the intermediate buoy is sunk into the sea together with the elongated body in a state in which the intermediate buoy is attached.

[Function] When the intermediate buoy is sunk into the sea together with the long body with the intermediate buoy attached to the long body in this way, the work of attaching the intermediate buoy to the long body is easy, and the work is easy. Two work vessels above sea level where work can be carried out safely.

This can be done first on land, etc.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIGS. 1A to 1C show a first embodiment of the present invention. As shown in FIG. 1A, the elongated body 5 is laid by a laying ship 10 toward a floating plant 11 held at a predetermined position on the sea surface 6. A sinker chain 12 is fixed in advance to the long body 5 at a point near the bottom of the part where the long body 5 is raised from the seabed 4 to the floating plant 11, and the laying ship 10 is moved to the floating plant 11. When approaching, the sinker chain 12 is sunk together with the elongated body 5 to land on the bottom. Further, an intermediate buoy 1 is attached on the laying ship 10 to a portion near the middle of the elongated body 5 in the longitudinal direction of the portion raised from the seabed 4 to the floating plant 11. As shown in FIG. 2, the intermediate buoy 1 is attached to a long body bending restriction device 13, and is attached to the long body 5 via the long body bending restriction device 13. The elongated body bending regulating tool 13
It has an arcuate bending regulating surface 13A that regulates bending so that it does not bend beyond the allowable bending radius. The elongated body 5 is placed on the bending regulating surface 13A and fixed to the elongated body bending regulating device 13 using a central fixture 14.

Further, a sinker (or anchor) 15 for mooring the intermediate buoy 1 in the sea is attached in advance to the lower surface of the elongated body bending regulating device 13 via a wire (or chain) 16. The length of the wire (or chain) 16 at this time is set so that the height at which the intermediate buoy 1 should be floated in the water can be obtained.

After completing such work, a pull rope 17 is connected to the tip of the long body 5, and the long body 5 is pulled through the pull rope 17 to fix the tip of the long body 5 to the floating plant 11. do.

Thereafter, as shown in FIG. 1(B), the intermediate buoy 1 and the sinker (or anchor) 15 are lifted together with the long body 5 by the crane 19 of the crane ship 18, and the intermediate buoy 1 and the sinker (or anchor) 15 are lifted. It is sunk into the sea together with the long body 5. In this way, as shown in Figure 1 (C),
The intermediate buoy 1 floats at a predetermined position in the sea, and the elongated body 5 has a catenary shape on both sides thereof.

By employing the method of this embodiment, catenaries on both sides of the intermediate buoy 1 can be formed at the same time. Further, since the intermediate buoy 1 is attached to the elongated body 5 in advance, there is no need to attach the intermediate buoy 1 to the elongated body 5 underwater. Additionally, most work can be done on the surface of the sea, where it is much easier to work than underwater.

Incidentally, the attachment of the intermediate buoy 1 to the elongated body 1 can also be carried out in advance on land.

Further, the attachment of the intermediate buoy 1 to the long body 5 may be carried out on the work boat using a work boat other than the construction ship 10, or on the sea surface immediately before the long body 5 is sunk into the sea. can. Even with this kind of work, the workability is much better than work under the sea.

Also, the work of fixing the tip of the elongated body 5 to the floating plant 11 may be done at the same time as the work of attaching the intermediate buoy 1 to the elongated body 5, or
Or it may be done before the installation work.

Furthermore, the floating plant 11 is used in place of the laying ship 10 to lay the elongated body 5 on the seabed, and when the elongated body 5 is laid, an intermediate buoy is attached to the elongated body 5 on the floating plant 11 or in the sea near the floating plant 11. 1 may be attached.

To attach the sinker (or anchor) 15 to the intermediate buoy 1 via the wire (or chain) 16, the sinker (or anchor) 15 is first sunk, and another A buoy is attached and floated on the sea surface 6, and when the intermediate buoy 1 is submerged together with the long body 5, a wire (or chain) 16 is connected to the intermediate buoy 1, and the intermediate buoy 1 is placed at a predetermined depth in the sea. It may be allowed to sink.

Since the elongated body 5 of the startup part is required to have stronger strength than the part that is on the bottom of the seabed 4, a long elongated body 5 for startup with greater strength is connected in advance via the connection part 20. It is preferable.

As shown in FIG. 3(A), when starting up and laying work is performed after pulling up the terminal side part of the elongated body 5 that has been laid on the seabed 4 in advance, the end of the elongated body 5 is A pull rope 21 is connected to the rope 5A in advance, another buoy is attached to the tip of the pull rope 21, and the rope is floated on the sea surface 6, and while the pull rope 21 is pulled by the laying ship 10 during the start-up and laying work, Move the laying ship 10 in the direction of the arrow, lift the terminal 5A of the elongated body 5 onto the laying ship 10 as shown in FIG. 3(B), fix the terminal 5A to the laying ship 10, and 5 on the terminal 5A side is collected for a predetermined length onto the laying ship 10 as shown in FIG. 3(C). At this stage, the above-mentioned figure 1 (A)
Start up and install the cables as shown in ~(C).

In addition, the work of standing up and laying the long body 5 can be carried out by using a work boat other than the laying ship 10 and lifting the end 5A of the long body 5, or by floating it without using the laying ship 10 or the work boat. plant 1
This may be carried out after lifting the terminal 5A of the elongated body 5 onto the sea at or near the sea.

It should be noted that the laying ship and work ship do not need to be dedicated vessels.
Tankers such as oil transport ships, general cargo ships, fishing boats, tugboats, etc. may be substituted. The same applies to floating plants, and ships for various purposes such as those mentioned above may be used instead.

Contrary to the above, the work of raising and laying the elongated body 5 can also be performed from the floating plant 11 side first.

Furthermore, in the above embodiment, an example was shown in which the intermediate buoy 1 is moored to the anchor (or sinker) 15 via the wire (or chain) 16 (Raizui S method). It can be similarly applied to a raising method (raise-wave method) in which the wire (or chain) 16 to be connected is not moored and is freely supported.

[Effects of the Invention] As explained above, the method for standing up and laying an elongated body for a floating plant according to the present invention involves sinking the intermediate buoy together with the elongated body into the sea with the intermediate buoy attached to the elongated body. The work for attaching the intermediate buoy to the elongated body can be performed first on the sea surface, on a work boat, on land, etc., where work is easy, and work efficiency can be significantly improved.

[Brief explanation of the drawing]

Figures 1 (A) to (C) are process diagrams of an embodiment of the method for standing up and laying a long body according to the present invention, and Figure 2 shows the intermediate buoy, bending control device, wire (or chain) used in this embodiment. ) and sinker (or anchor) - Front view showing an example, Figure 3 (A
) to (C) are process diagrams showing the lifting work of a long body laid in advance on the seabed, and FIG. 4 is a side view of the long body lifted by the conventional long body raising and laying method. . 1... Intermediate buoy, 4... Seabed, 5... Long body, 6
... Sea surface, 10 ... Laying ship, 11 ... Floating plant, 13 ... Long body bending restriction device, 13A ... Bending restriction surface, 14 ... Fixing device, 15 ... Sinker (or anchor), 16...wire (or chain), 17
...Pull rope. Procedural amendment (master) February 22, 1989

Claims (1)

[Claims] An intermediate buoy is attached to a midway portion of a long body raised between the seabed and the floating plant, the intermediate buoy is floated in the sea, and the long body forms a catenary on both sides of the intermediate buoy. A method for standing up and laying a long body for a floating plant, characterized in that, with the intermediate buoy attached to the long body, the intermediate buoy is submerged in the sea together with the long body. How to lay a shaku body.