JPS6354600B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semi-submersible work vessel for installing large offshore structures, and more specifically, a semi-submersible work boat for use in installing large offshore structures such as plants on foundation structures provided on the ocean. Regarding semi-submersible work boats.

For example, a plant mounted on a substructure on the sea is large in size and weight, so it is impossible to construct it as one piece and install it on the substructure using a crane or the like. For this reason, conventionally, plants were constructed by dividing them into multiple relatively small blocks (modules) according to the capacity of cranes, etc., and these blocks were mounted one by one on the foundation structure and assembled on site. I'm wearing it. Therefore, there is a problem that on-site installation work is inefficient and takes a long time.

For example, when installing a relatively small structure on the sea, multiple foundation piles are set up at intervals on the sea, the structure is supported on the barge with it protruding from both sides, and the barge is attached to the foundation piles. A method is known in which a structure is mounted on foundation piles by entering the barge between the foundation piles and moving the barge up and down by adjusting the water intake (see Japanese Patent Laid-Open No. 55-36147).

However, when a structure becomes large, it cannot be supported by foundation piles alone, and the structure of the foundation structure on which the structure is mounted becomes complicated, making it difficult to allow a barge to enter between the foundation structures. becomes impossible. In addition, especially in the case of a large structure with a large weight, supporting it on a barge in a state that projects from both sides poses a problem from the viewpoint of safety. Therefore, if the structure becomes large, it is impossible to install it using the above method.

This invention was made in view of the above circumstances, and allows a large offshore structure (or a large block thereof) constructed as one piece to be safely and easily mounted on a foundation structure, and is The purpose of the present invention is to provide a work boat that can significantly shorten the period of on-site installation work.

The present invention will be described below with reference to drawings showing embodiments.

A semi-submersible work boat 1 for installing large offshore structures includes a lower hull 3 having a pair of left and right trunks 2, a plurality of guide posts 4 respectively erected on each trunk 2 of the lower hull 3, and It consists of an upper hull 6 having a pair of left and right trunks 5 each attached to a guide post 4 of a lower hull 2 so as to be vertically movable. The lower hull 3 and the upper hull 6 are each integrally constructed so as to form a U-shape when viewed from above, and the front ends of the left and right bodies 2 and 5 of each hull 3 and 6 are connected to each other. The upper surface of the lower hull 3 and the upper hull 6
The top and bottom surfaces of the board are horizontal. Lower hull 3
Guide posts 4 are fixed to the front, center and rear of the upper surface of each body 2, respectively, and the upper ends of the left and right guide posts 4 in pairs are connected to each other by horizontal connecting rods 7, respectively. On the upper surface (deck) of the upper hull 6, the entire width of the front part, each fuselage 5
Rectangular parallelepiped buoyancy chambers 8 and 9 are provided at the center and rear of each body 5, and a jack up device 1 is provided on the upper surface of the buoyancy chambers 8 and 9 at the front, center and rear of each body 5.
0 is provided for each. Each guide post 4
vertically penetrates the upper hull 6, the buoyancy chambers 8 and 9, and the jack up device 10, and the upper hull 6 is connected to the guide post 4 by the jack up device 10.
The guide post 4 can be moved up and down along the guide post 4 and fixed at any position on the guide post 4. Each of the buoyancy chambers 8 and 9 is provided at a predetermined distance apart from the inner end of the upper hull 6, and the upper surface of the inner end of the upper hull 6 inside the buoyancy chambers 8 and 9 is connected to the marine structure mounting section 11. It's summery. Further, the lower hull 3 and the upper hull 6 are each provided with a ballast tank (not shown).

The plant 12 is built in a box shape so as to float on the sea surface, and has a plurality of legs 1 on the inner part of the lower surface.
3 is fixed. A jacket (foundation structure) 14 on which the plant 12 is mounted is fixed to the seabed, and a plurality of support cylinders 15 into which the legs 13 of the plant 12 are fitted are fixed to the upper end of the jacket 14 protruding above the sea surface. ing.

The installation of a large offshore structure, such as a plant 12, by the work boat 1 described above is carried out as follows.

First, plant 12 is built in one piece in the factory,
Pull this out to the surface of the sea and float it. Next, with the upper hull 6 lowered to the upper surface of the lower hull 3, the work boat 1 is lowered by adjusting the ballast so that the upper surface of the upper hull 6 is located slightly below the lower surface of the plant 12. Then, the plant 12 is pulled into the work boat 1 through between the left and right buoyancy chambers 9 (see FIG. 1). At this time, the legs 13 of the plant 12
are located between the left and right trunks 5 of the upper hull 6. Note that when pulling in the plant 12, the work boat 1 may be moved instead of moving the plant 12. After the plant 12 is pulled in to a predetermined position, the work boat 1 is floated by adjusting the ballast until the upper part of the lower hull 3 protrudes above the sea surface (see FIGS. 2 and 3). By floating the work boat 1, one end and both ends of the plant 12 are supported by the mounting portion 11 of the upper hull 6. Once the plant 12 is mounted on the work boat 1 in this manner, the plant 12 is fixed to the upper hull 6 as required, and the work boat 1 is towed close to the jacket 14. At this time, since the upper hull 6 has descended to the upper surface of the lower hull 3 which has been floated to the sea surface, stability is good and propulsion resistance is low.
Next, the upper hull 6 is raised along the guide post 4 by the jack up device 10, and the lower end of the leg 13 of the plant 12 is raised to the support tube 1 of the jacket 14.
The upper hull 6 is fixed at a position slightly higher than the upper end of the upper hull 5. Then, the work boat 1 is moved backward so that the jacket 14 enters between the left and right trunks 2 from the rear open end of the lower hull 3, and the legs 13 of the plant 12 are attached to the corresponding support tubes 15 of the jacket 14. The work boat 1 is stopped so that it is positioned directly above (see Fig. 4). Next, the upper hull 6 is lowered along the guide post 4 to the upper surface of the lower hull 3 by the jack up device 10 (see FIG. 5).
At this time, the plant 12 also descends together with the upper hull 6, and the lower part of the leg 13 eventually fits into the support tube 15, so that the plant 12 is supported by the jacket 14 and stops. descend away from. And finally,
Work boat 1 is moved forward and removed. At this time, since there is nothing at the rear of the workboat 1 that interferes with the jacket 14 and the plant 12 mounted thereon, only the workboat 1 can be moved forward.

When lifting the plant 12 by raising the upper hull 6 along the guide post 4, the upper hull 6 is lowered while lowering the lower hull 3 along with the guide post 4.
If it is floated on the sea surface and raised relative to the guide post 4, the capacity of the jack up device 10 can be reduced, or the jack up device can be eliminated and only a device for fixing the upper hull 6 to the guide post 4 can be used instead. It is also possible to do so. In this case, after lowering only the lower hull 3 and guide post 4 as described above, fixing the upper hull 6 to the guide post 4 so that there is a predetermined distance between it and the lower hull 3, and then When the lower hull 3 is floated by adjustment, the upper hull 6 is lifted above the sea surface.

The configurations of the lower hull 3 and the upper hull 6, the number of guide posts 4, etc. are not limited to those of the above embodiment.
It can be changed as appropriate. In the above embodiment, the distance between the front parts of the left and right trunks 2 of the lower hull 3, between the front parts of the left and right trunks 5 of the upper hull 6, and between the upper ends of the three pairs of left and right guide posts 4 is They are connected to each other to increase the strength of the work boat 1, but if there is no problem with the strength, the lower hull 2 and the lower part of the guide post 4 can be connected at either the front or rear of the hulls 3, 6. At least any one of the left and right parts, the upper parts of the left and right guide posts 4, and the left and right upper hull parts 5 may be connected. Further, the work boat may be equipped with a propulsion device.

As described above, the work boat according to the present invention includes a lower hull 3 having a pair of left and right bodies 2, and a lower hull 3 having a pair of left and right bodies 2.
a plurality of guide posts 4 erected on each of the hulls 2, and guide posts 4 on each of the lower hulls 2;
The front part of the hulls 3 and 6 consists of an upper hull 6 having a pair of left and right trunks 5 that are vertically movable, respectively, and a device 10 for fixing the upper hull 6 to an arbitrary position on the guide post 4. and the lower hull 2 and guide post 4 on either side of the aft part.
The left and right parts including the lower part, the upper parts of the left and right guide posts 4, and the left and right upper hull parts 5 are connected at least at one point, and the front part of the hulls 3, 6 or Since there is an open space between the left and right bodies 2 and 5 at the rear, even if the offshore structure is large and the foundation structure is complex, it is possible to construct a large offshore structure that is built as one piece and floats on the sea surface. Place it on the upper hull 6 and lift it above the sea level, and move the work boat so that the foundation structure enters between the left and right hulls 2 and 5 from the front or rear open ends of the lower hull 3 and upper hull 6. By moving the upper hull 6 up and down, the large marine structure can be moved onto the foundation structure and easily mounted thereon. Since the upper hull 6 can move up and down with respect to the guide post 4 of the lower hull 3 and is fixed at any position on the guide post 4, when moving a large offshore structure, the lower part floating on the sea surface can be moved freely. The upper hull 6 can be lowered to the upper surface of the hull 3, and when moving a large offshore structure onto a foundation structure, the upper hull 6 is fixed to the upper part of the guide post 4 and the large offshore structure is moved upward. Can be lifted. Therefore, the stability during movement of the large offshore structure is good, the propulsion resistance is small, and the installation of the large offshore structure is easy.
Therefore, the construction period for on-site installation work and the overall construction period can be significantly shortened. In addition, it is possible to integrate large structures or to enlarge blocks, and the number of parts to be built in a well-managed factory increases, making it possible to obtain large structures of high quality.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional view showing the state immediately before the plant is mounted on the work boat, FIG. 2 is a plan view showing the state where the plant is mounted on the work boat, and FIG. 4 is a longitudinal sectional view showing the state immediately before the plant is mounted on the jacket, and FIG. 5 is a rear view showing the state immediately after the plant is mounted on the jacket. 1... Work boat, 2... Lower hull, 3... Lower hull, 4... Guide post, 5... Upper hull, 6... Upper hull, 10... Jacket up device, 12... Plant (Large offshore structures), 14
...jacket (foundation structure).

Claims (1)

[Claims] 1. A lower hull 3 having a pair of left and right trunks 2, a plurality of guide posts 4 erected on each trunk 2 of the lower hull 3, and a vertically movable guide post 4 of each lower hull 2. It consists of an upper hull 6 having a pair of left and right trunks 5 that are freely attached, and a device 10 for fixing the upper hull 6 to any position on the guide post 4. On one side, at least one of the parts between the left and right parts including the lower hull 2 and the lower part of the guide post 4, between the upper parts of the left and right guide posts 4, and between the left and right upper hull parts 5 is A connected semi-submersible work vessel for installing large offshore structures.