JPS6058328B2 - How to install a bottom-mounted offshore structure using a used tanker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for installing a bottom-mounted marine structure using a used tanker.

When constructing a bottom-mounted marine structure such as a breakwater using a used tanker, a mound is set up on the seabed using rubble, etc., the tanker is floated on the sea surface and towed above the mound, and then water is poured inside. Then, instead of water, the tanker is filled with solid heavy objects such as concrete or earth and sand, and installed on the mound.The frictional force between the tanker and the mound prevents it from moving horizontally due to waves, etc. are doing.

In order to increase the frictional force between the tanker and the mound to reliably prevent horizontal movement of the tanker, it is necessary to increase the coefficient of friction between them, or to increase the friction between the tanker and the solid heavy objects packed inside it. It is necessary to increase the total weight of However, in the case of tankers, the hull is made of steel, so the coefficient of friction between the tanker and the mound is smaller than that of a concrete caisson, and in order to obtain the same frictional force as a concrete caisson, it is necessary to It is necessary to increase the total weight by about 50% compared to the case of a concrete caisson, which is uneconomical. This invention was made in view of the above-mentioned circumstances, and it increases the resistance to waves etc. without increasing the total weight of the used tanker and solid heavy objects, and allows the horizontal movement of the Nakayoshi tanker. The purpose of the present invention is to provide a method for installing a bottom-mounted marine structure using a used tanker, which can reliably prevent the above.

In the method according to the present invention, when a used tanker is installed as a bottom-mounted marine structure by sinking it on a mound on the seabed, the bottom shell plate, the lower part of the side shell plate and After separating these aggregates attached to the hull from the hull and cutting and removing the lower part of the remaining side hull plating, the parts that were previously cut from the hull are lifted and reattached to the longitudinal bulkheads and side hull plating, thereby reattaching the bottom of the ship. A convex portion is formed in the center in the left-right direction, a concave portion is provided on the upper surface of the mound on the seabed to accommodate the convex portion, and the used tanker is sunk onto the mound so that the convex portion of the bottom of the ship fits into the concave portion. Afterwards, sand or the like is filled between the convex part of the ship's bottom and the peripheral wall of the concave part of the mound.

According to this invention, the convex part of the bottom of the ship is fitted into the concave part of the top surface of the mount, and sand or the like is filled between the convex part and the peripheral wall of the concave part, so that the total weight of the tanker and solid heavy objects packed inside it can be reduced. Even if it is not made large, the resistance against waves and the like increases, and horizontal movement of the tanker can be reliably prevented.

Embodiments of the present invention will be described below with reference to the drawings. First, as shown in FIG. 1, a used tanker 1 to be used as a bottom-mounted offshore structure is pulled into the dock 2, and the lower part of the outer bottom outer panel and the outer outer panel 5 of the left and right longitudinal bulkheads 3 is placed inside the dock 2. and aggregate 6 including large bones and small bones attached to these outer plates 4 and 5
Cut both ends and separate it from the hull.

After cutting and removing the remaining lower part of the hull side skin 5, the part that was previously separated from the hull is lifted up with a jack (not shown), and the vertical bulkhead 5 is reattached as shown in FIG. and welded to the ship's side outer plate 5, thereby forming a convex portion 7 at the center of the ship's bottom in the left-right direction. Further, a plurality of vertical pipes 10 extending from the upper deck 9 immediately outside the vertical bulkhead 3 to the bottom shell 4 are appropriately arranged in the side tank 8 of the tanker 51.
On the other hand, a mount 11 is provided with rubble on the seabed at the site where the used tanker is installed, and a recess 12 is formed on the upper surface of the mount 11 to accommodate the protrusion 7 on the bottom of the ship.

Then, the tanker 1 modified as described above is pulled out to sea and towed above the mount 11, water is poured inside, and the tanker 1 is mounted on the mount 11 so that the protrusion 7 on the bottom fits into the recess 12 of the mount 11. sink to the top. Next, solid heavy materials such as earth and sand are poured into the hull, and the tanker 1
is installed at a predetermined position on the mount 11. Finally, as shown in FIG.
3, etc., and complete the installation of tanker 1.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention in the order of steps, and FIG. 1 is a cross-sectional view showing a used tanker at a dock before modification, and FIG.
The figure is a cross-sectional view showing the modified used tanker at the dock, and FIG. 3 is a cross-sectional view showing the used tanker installed on the mount. 1... Used tanker, 2... Dock,
3... Vertical bulkhead, 4... Bottom shell plate, 5...
...Side shell plating, 6...Aggregate, 7...
Convex portion, 11... Mount, 12... Concave portion, 13
······sand.

Claims (1)

[Claims] 1. When installing a used tanker as a bottom-mounted marine structure by sinking it on a mound on the seabed, in advance, in the dock, the bottom skin, the lower part of the side skin, and the parts attached to the left and right vertical bulkheads of the used tanker shall be After separating the aggregate from the hull and cutting and removing the lower part of the remaining side shell plating, the parts that were previously separated from the hull are lifted and reattached to the longitudinal bulkheads and the side shell plating, thereby attaching the material to the center of the ship's bottom in the lateral direction. A convex portion is formed, and a concave portion is provided on the top surface of the mound on the seabed to accommodate the convex portion. After sinking this used tanker onto the mound so that the convex portion on the bottom of the ship fits into this concave portion, the bottom of the ship is A method for installing a bottom-mounted marine structure using a used tanker, which is characterized by filling sand or the like between the convex part and the circumferential wall of the concave part of the mound.