JP2977175B2 - How to lay underwater cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of laying a submarine cable in which a submarine cable is drawn out from a laying cable laying ship and laid and buried in the water bottom, and in particular, the presence or absence of obstacles on the water bottom is monitored. The present invention relates to a method of laying a water bottom cable while performing.

[0002]

2. Description of the Related Art In a submarine cable laying work, a submarine cable (mainly a submarine cable) drawn out from a cable laying ship is laid and buried at the same time as excavation of the water bottom using a burying machine towed by the cable laying ship. If there is an obstacle on the bottom of the water, it will not only be impossible to lay and bury the underwater cable, but also the buried machine may collide with the obstacle and cause an accident such as falling down. In addition, it is necessary to check the water bottom of the submarine cable laying route to check for obstacles. For this reason, conventionally, prior to the installation work of the submarine cable, the side scan sonar 1 is towed by the tugboat 2 along the installation route as shown in FIG. The water bottom surface 3 having a width B is scanned as necessary to confirm the presence or absence of an obstacle. It should be noted that scanning the width B appropriately as described above requires a certain margin (range) in the left-right direction because the actual cable laying position may slightly deviate left and right from a predetermined position. This is because it is necessary to carry and investigate.

[0003]

As described above, in the conventional method, confirmation of the presence or absence of an obstacle is not performed simultaneously with the work of laying the underwater cable, that is, it is performed in advance before laying the cable. Therefore, if there is any change in the water bottom of the laying route between the end of the water bottom survey and the start of the laying work, for example, an obstacle on the laying route that would be an obstacle for the burial machine may be illegally dumped. In such a case, even though the laying route has changed to such an inconvenient and dangerous state, the laying work will be carried out without grasping such a situation. There was a risk of encountering an accident.

[0004] The present invention has been made in view of the above points,
When laying and burying the submarine cable unwound from the cable laying ship using a burying machine, a new submarine cable that can safely lay and embed the submarine cable while monitoring the water bottom and reliably avoiding obstacles. It is an object to provide a laying method.

[0005]

To solve the above problems SUMMARY OF THE INVENTION The laying method underwater cable of the present invention, the progress of the cable laying ship
Scan a generally linear bottom area that extends back and forth
The side scan sonar arranged is used to advance the cable laying ship.
The submarine cable on the cable laying ship is extended to the water bottom while being reciprocated in the width direction of the laying ship perpendicular to the direction, while monitoring the water bottom surface.

[0006]

In the above construction, the cable laying ship sails on the laying route and continuously draws out the loaded submarine cable and lays it on the water bottom. At that time, the side scan sonar is a generally linear
While scanning the water bottom area,
Since it reciprocates in the width direction of the cable laying ship at right angles, it is possible to monitor the forward position of the cable laying ship in a range having a certain width in the left-right direction from the planned cable laying position. Therefore, if there is an obstacle in the installation route and its vicinity, this obstacle can be found and avoided with sufficient margin, and the cable can be installed safely.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the method of the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral 11 denotes a cable laying ship. The cable laying ship 11 draws out the water bottom cable 12 from the cable coil 12 ′ through the horn 13, the brake 14, the stern sheave 15, etc., excavates the water bottom surface 16 with the burying machine 15 pulled by a wire rope, and at the same time simultaneously excavates the water bottom cable 12. Do the work of burying. As the burying machine 15, a water jet burying machine or a ski burying machine is usually used. The embedding machine 15 in the illustrated example is a water jet embedding machine, and has a nozzle 15a for jetting water.

Although the above-described structure is a conventional general structure, in the embodiment of the present invention, a side extending in the width direction of the cable laying ship 11 (in the direction of the arrow (a) in FIG. 2), for example, on the bow side of the cable laying ship 11. Rail-shaped pedestal 17 for mounting scan sonar
Is installed at the lower end of the inverted L-shaped support member 18 which is reciprocally driven in the width direction of the laying boat along the gantry 17 in a direction orthogonal to the moving direction along the gantry 17 (that is, the width direction of the laying boat). A side scan sonar 19 for scanning is attached. That is, the side scan sonar 19 itself is arranged in the direction of the width of the laid ship,
It is generally linear (but not sonar)
(Including excluding the area immediately below).
Check. It should be noted that even if it is referred to as “linear,”
Like the general side scan sonar,
Of course, it has a slight scanning width in the direction.

The above cable laying ship 11 and the burying machine 1
5, when laying the underwater cable, the cable laying ship 11 sails on the laying route and continuously draws out the underwater cable 12 from the cable coil 12 'while excavating the underwater surface 16 by the underwater cable burying machine 15. And buried under the water. At that time, side scan sonar 1
Numeral 9 reciprocates along the gantry 17 in the laying ship width direction (the direction of the arrow (a)) perpendicular to the traveling direction of the cable laying ship 11. Therefore, the side scan sonar 19 is arranged substantially before and after the cable laying ship 11 in the traveling direction.
Is scanned over the range of the width B ′. As a result, the width B 'in the left-right direction from the cable laying (burial) scheduled position
The forward position of the laying boat 11 in a range having a margin is monitored, and the presence or absence of an obstacle is confirmed. Therefore, if there is an obstacle in the installation route and its vicinity, the obstacle can be found and avoided with a sufficient margin, and the cable installation work can be performed safely.

The position where the side scan sonar 19 is provided is suitably on the bow side as in the embodiment, but is not necessarily limited to the bow, and may be an intermediate position or a stern. In the embodiment, the case where the underwater cable 12 is buried using the underwater cable burying machine 15 has been described. However, the present invention can be applied to a case where only the cable is laid without excavating the bottom 16. It is. In addition, the cable laying ship may be self-propelled or tugboat.

[0011]

According to the present invention, the front and rear sides of the cable laying ship are scanned substantially over the range of the laying ship width by the side scan sonar provided on the cable laying ship so as to be able to reciprocate in the width direction of the laying ship. Because the cable is laid on the bottom of the water while monitoring the water, the position in front of the cable laying ship in motion can be monitored over the width of the laid ship. Therefore, if there is an obstacle in the laying route and its vicinity, the obstacle can be found and avoided with sufficient margin, and the cable laying operation can be performed appropriately and safely. This is particularly effective in submarine cable laying and burying work in which submarine cables are buried using a submarine cable burying machine.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a situation where a submarine cable is laid by a method according to an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a front view of FIG. 1;

FIG. 4 is a view for explaining a conventional method, and is an explanatory view of a state where an investigation of a water bottom is performed by a side scan sonar towed body prior to a work of laying a water bottom cable.

FIG. 5 is a front view of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Cable laying ship 12 Underwater cable 15 Underwater cable burying machine 16 Underwater surface 17 Mount 18 Support member 19 Side scan sonar

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-126490 (JP, A) JP-A-1-320486 (JP, A) JP-A-4-254283 (JP, A) 41084 (JP, B2) JP-B-56-27052 (JP, B2) JP-B-58-50082 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02G 9/00-9 / 12 H02G 1/10

Claims (1)

(57) [Claims] 1. The cable laying ship extends in the forward and backward directions of travel.
Side skis arranged to scan a generally linear bottom area
Use a sonar that is orthogonal to the direction of travel of the cable laying ship.
A method of laying a submarine cable, wherein the submarine cable on a cable-laying vessel is extended to the bottom of the water while the submarine cable is monitored while monitoring the water bottom by reciprocating in the width direction of the marine vessel.