JPS5850082B2 - Method for laying long submarine multi-stripes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for laying multiple (two or more) long bodies such as submarine cables and water pipes on the seabed.

As a recent trend, there has been an increase in the number of long pieces being laid in multiple strips.
In addition, due to various conditions such as bottom sediment, water depth, fishing area, etc., it has become necessary to lay several long structures side by side in a narrow area.

In the case of such multi-strip installation, care must be taken during installation to ensure that the elongated bodies do not come too close to each other or intersect with each other.

For this reason, recently, the distance between the long body that was previously laid and the long body that is currently being laid has been measured by submerging a dipper.

This requires a great deal of effort and expense, and has the drawback that it is impossible to measure distances in sea areas where a diver cannot dive due to fast currents or other reasons.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for laying multiple strips of an elongated body on the seabed, which allows the installation of multiple strips of the elongated body to be carried out while measuring the installation position of the elongated body on a ship.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIGS. 1 to 3 show an embodiment of the method for laying multiple strips of elongated bodies on the seabed according to the present invention.

In this embodiment, a long body 2 is sent out into the sea from a laying ship 1,
Laying is carried out on the seabed 3 while the laying ship 1 is moving forward.

At this time, a surveying vessel 4 is positioned after the laying vessel 1, and an acoustic probe 5 such as an acoustic minesweeper mounted on the surveying vessel 4 is used to compare the elongated body 2 that is currently laid and landed on the seabed with the long body 2 that was laid last time. The distance X between the elongated body 2' and the long body 2' that has landed on the seabed is measured, and the laying ship 1 is controlled based on this distance X, and both the elongated bodies 2 and 2 are
′ are always located at the same spacing.

In this embodiment, the distance X between the two projection bodies 2 and 2' is measured as follows.

That is, two transducers 6 of an acoustic probe 5 such as an acoustic minesweeper
, 6' are suspended from the survey ship 4 into the sea by the suspension means 7, and one of the transducers 6 is oriented so as to detect the elongated body 2,
The other transducer 6' is designated so that it can detect the elongated body 2', and the angle formed by both transducers 6, 6' is fixed at α.

By doing this, the distance y from the transducer 6 to the elongated body 2 and the distance 2 from the transducer 6' to the elongated body 2' can be measured. ′ angle α
Since this is known, the distance X between the two projection bodies 2, 2' can be determined from the following equation: X=zsinα or x=ytanα.

Such processing is performed by the acoustic probe 5 on the surveying ship 4, and plotted on the recording paper 8 as a trajectory 9 as shown in FIG.

In order to measure the distance X between both elongated objects 2 and 2' in this manner, it is necessary to ensure that the transducer 6 is always located directly above the elongated object 2.

Therefore, the survey ship 4 is maneuvered so that the transducer 6 travels directly above the elongated body 2.

FIG. 5 shows another embodiment of the laying method of the present invention.

In this embodiment, an example in which a fish finder with a scanner or the like is used as the acoustic probe 5 is shown.

That is, in this acoustic probe 5, one transducer 6 is skinned at a predetermined angle α, and the distance y from the transducer 6 to the elongated body 2 and the elongated body from the transducer 6 are The distance 2 to the body 2' is measured, and the distance X is determined using the same processing method as described above.

The survey ship 4 does not measure the long body 2 before it reaches the bottom of the ocean floor 3, but measures the long body 2 after it has reached the bottom.
It is preferable to connect the survey ship 4 with a wire 10 or to control the survey ship 4 so that the distance between the two ships is at least a certain value.

As explained above, in the present invention, the distance between the elongated body currently on the seabed and the previously laid elongated body is measured using an acoustic probe mounted on a survey ship, and the multi-striped elongated body is then laid. Therefore, it is possible to maintain the mutual spacing between the elongated bodies at a substantially required interval when laying the elongated bodies.

In addition, in the present invention, measurements are carried out using a surveying vessel located behind the laying vessel, so even when a long body is being laid while being carried away by the current, it is easy to remove the long body. can be tracked and correct measurements can be taken.

Moreover, in the present invention, since the distance between the elongated bodies is measured after both of them have landed on the seabed, the measurement is reliable, and the measurement can be performed correctly from this point of view as well.

Furthermore, in the present invention, since the measurement is performed using an acoustic probe, the measurement can be carried out without any problem even in deep sea areas where a dialer cannot dive, and the measurement can be carried out more easily than other methods.

[Brief explanation of the drawing]

1 to 3 are a side view, front view, and plan view showing an example of the implementation state of the laying method of the present invention, FIG. 4 is a diagram showing the recording state of the recording paper, and FIG. It is a front view of another implementation state. 1... Laying ship, 2, 2'... Long body,
3... ocean floor, 4... survey ship, 5...
...Acoustic probe, 6,6'...Transmitter/receiver.

Claims (1)

[Claims] 1. In a method for laying multiple strips of long strips on the seabed at required intervals, a survey ship is positioned after the laying ship that is carrying out the work of laying the long strips, and the surveying While measuring the distance between the long body currently on the seabed and the long body previously laid on the seabed using an acoustic probe mounted on the ship, the laying vessel is maneuvered based on this measured distance. 1. A method for laying multiple strips of long bodies on the seabed, characterized by laying the long bodies at required intervals.