JPH0669251B2 - How to lay a submarine cable - Google Patents

Description

TECHNICAL FIELD The present invention relates to the laying of a submarine cable that can shorten the laying period when laying a power cable, a communication cable, etc. on the seabed, lake bottom, riverbed, etc. Regarding the method.

(Prior art) When laying cables such as electric power cables and communication cables on the bottom of water such as the sea bottom, lake bottom, river bottom, etc., in order to prevent the cables from being damaged by bottom fishing gear or anchorage of ships. It is common to bury the cable at the bottom of the water. In this case, the laying speed differs depending on various conditions, but it is 1
Since it is about 100 to 1000 m, assuming that the length of the installation route is 20 km, the number of days required for the installation work is 20.
~ 200 days will be long. Since the seabed or the water area along the laying route is occupied during this laying work period, there is a drawback that the fishing boat and the area hinder the vessels sailing near the laying route. In this way, the installation period is 20 to 20
Since it lasts for a long time of 0 days, there is a high possibility of encountering bad weather during cable laying, and if bad weather is encountered, there is a high risk that the cable will be cut and it will be impossible to lay the cable for a long time.

(Problems to be Solved by the Invention) The present invention has been made in view of the above, and provides a method of laying a water bottom cable, which can shorten the laying time of the water bottom laying of a cable or the like compared to the conventional method. Its purpose is to provide.

(Means for Solving the Problem) According to the present invention, two laying vessels each carrying a cable length obtained by dividing a submarine cable laying route into two are circulated to a dividing point of the laying route, and the cable is laid at the dividing point. The two vessels are connected to each other and are laid by advancing in opposite directions.

(Embodiment) The configuration and operation of the present invention will be described in detail below with reference to the embodiment shown in the drawings. FIG. 1 is a schematic explanatory diagram in the case of laying a submarine cable on a submarine cable laying route according to the present invention. In the figure, A and B are land portions, and a water area C for laying the submarine cable is interposed between A and B. To do.
a and b are the landing points to the land portions A and B of the underwater cable laid on the water bottom in the water area C, respectively.
The bottom of the water between b is the route for laying the bottom cable.
m is a substantially central position of the length of the submarine cable route, and depending on this position, the submarine cable route is a, m
It is a division point that divides into two, i.e., the space and the space between b and m. At this time, the position of m is not necessarily the substantially central position of the cable route but is offset to either the a direction or the b direction because of the degree of difficulty of laying the submarine cable on the cable route or the navigation volume of the ship in the water area. It may be the position.
The submarine cable laying vessels 1 and 2 are each a submarine cable laying vessel 1 moored on the a side of the division point m. The submarine cable is laid on the cable route between a and m, and on the b side of the division point m. On the submarine cable laying ship 2 which is anchored, a submarine cable which is necessary and sufficient for laying a submarine cable on the cable route between m and b is loaded and circulated. Next, by connecting the ends of the respective submarine cables loaded on the cable laying vessels 1 and 2, the laying vessel 1,
2 of the submarine cables loaded in each of the laying vessels 1 and 2 along the submarine cable laying route in opposite directions.
The water bottom cable is laid along the entire length of the cable route by letting it go out from the position as the starting point while sailing underwater. At this time, the connection of the water bottom cable ends loaded on the laying vessels 1 and 2 is performed by any of the following methods. The second below
The same parts are denoted by the same reference numerals in FIGS.

(1) As shown in FIG. 2, a submarine cable laying vessel 1 (which lays a submarine cable C ₁ on the cable route between a and m in FIG. ₁ ) and a submarine cable laying vessel 2 (b, m in FIG. 1) A submarine cable C ₂ is laid on the inter-cable route, and C ₁ and C ₂ are submarine cables loaded on the laying vessels 1 and 2, respectively, and are substantially the same). The water-bottom laying cable guide devices 1 ', 1 "respectively provided on the stern at m positions in the respective traveling directions are so close as to contact the ends of the submerged laying cable guide devices 1', and the berth is brought into a state as shown in FIG. The cable connecting work in which the terminal portion of the water bottom cable C ₂ of ₂ is provided on the yagura 2 ′ of the laying ship 1 (which is a tower-like structure for pulling out the cable loaded on the laying ship and is temporarily installed on the laying ship). Stand Lead, subjected to each end connecting operation the cable C ₁ and the cable C ₂ in this location, the cable guide device 1 of the connection completion after the laying ship, 2 '
Each of the cables C ₁ C ₂ is fed from 1 ″ into the water and sails in opposite directions along the cable route to lay a submarine cable C ₁ C ₂ over the entire length of the cable route. In FIG. Although the connection work place is on the tower of the cable laying ship 1, it is not limited to this and may be on the tower of any of the cable laying ships 1 and 2.

(2) As shown in FIG. 3, at the position m in FIG. 1, the cable laying vessel 1 stops and the cable laying vessel 2 is advanced in the direction of the arrow to allow the cable C ₂ to slightly reach the cable route. Occasionally, the end portion of the cable laying vessel 2 is lifted to the cable connection location described in FIG. 1 of the cable laying vessel 1, and the cable laying vessel 2 continues its progress and terminates the submarine cables C ₁ and C ₂ on the cable laying vessel 1. After the connection is completed, the cable laying vessel 1 starts to move in the opposite direction to the laying vessel 2 and feeds out the cable C ₁ to lay a submarine cable C ₁ between the cable routes m and a.

(3) As shown in FIG. 4, the submarine cable connection dedicated vessel 3 is arranged between the cable laying vessels 1 and 2, and the submarine cables C ₁ and C ₂ loaded on each of the cable laying vessels ₁ and ₂
The cable laying vessels 1 and 2 are moved along their respective cable routes by lifting the end portions of the cables, and the cables C ₁ and C ₂ fed from these cable laying vessels 1 and ₂ are respectively bottomed so that the laying work is not affected. After the laying vessels 1 and 2 proceed to lay cables on the bottom of the water, respectively, terminating connection work of the bottom cables C ₁ and C ₂ is carried out by the dedicated bottom-bottom cable connecting vessel 3, and when the terminating connection is completed, the end connection portion J
Is dropped into the water together with the water bottom cables at both ends connected to the connecting portion J so that the cable does not cause a kink on the outside of the side of the special ship 3, and it is settled on the water bottom. During this time, the submarine cable laying is continuously advanced to the cable route by the cable laying vessels 1 and 2. FIG. 5 shows a plan view of the bottom shape of the submarine cables C ₁ and C ₂ connected as described above. In FIG. 5, C ₁ and C ₂ are the laying vessels 1 respectively.
And water bottom cables is laid at 2, C ₃ are each a plan view of wearing bottom of connected underwater cable portion on the bottom of the water cable connections only vessels 3, 3 is the underwater cable connection dedicated ships when cabling The position.

The submarine cable connection does not necessarily have to be a factory-assembled connection that has the perfect flexibility to be connected at the factory. It is easy to connect, and its structure is simple and rigid (the cable connection of the land cable). Part). However, from the viewpoint of ease of exterior construction and workability of laying the connecting portion, it is desirable that the connecting portion be as flexible as possible and have a so-called factory-assembled connecting portion having an equal outer diameter. In case of OF cable during cable laying, it is effective to install the cable connection work place on the laying ship or on the cable connection dedicated ship at the highest position of the passage of the submarine cable in order to ensure the vacuuming and refueling work. Target. Furthermore, the oil adjustment inside the cable connection is done wirelessly by the submarine cable 1,
A pressure tank (not shown in the drawing) provided at each of the two ends may be opened and closed. In the case of a pressure tank such as a CV cable or a water-bottom cable that does not require vacuuming, it is not necessary to connect the water-bottom cable laid at the highest position of the passage through which the water-bottom cable passes at the time of laying, as described above.

In the above embodiment, the laying route is divided into two and all routes are laid at once. However, when the laying route is long, the number of divisions may be increased to lay the route.

(Effects of the Invention) The applicant of the present invention previously filed Japanese Patent Application No. Sho 55 on February 6, 1980.
-13114 (Japanese Patent Laid-Open No. 56-112807) provided an invention similar to this invention. The gist of the invention is to move a first laying vessel loaded with a cable having a length corresponding to the length of a laying route to a position of approximately half of the laying route, and at that position, to move the first half of the cable of approximately half of the cable. The length is transferred from the first laying vessel to the second laying vessel, and
And the second laying vessel is moved in the opposite direction so as to face the laying route end, respectively, and the cable is unrolled and laid down.
(Hereinafter, it is referred to as an already-applied invention.) Since the present invention has the configuration and operation described in the section of the embodiments, according to the present invention, the following effects can be obtained in the water bottom laying of the water bottom cable.

(1) The difficult work in the previously filed invention of shifting half the length of the cable from the first ship to the second ship, which takes a long time at the position of the division point m, which is the starting point for laying the submarine cable while worrying about the weather It can be omitted and the cable laying vessel can be prevented from staying in the water area where the volume of navigation of the vessel is large for a long time, thus facilitating the navigation of other vessels.

(2) Since it is easy to form a part of the submarine cable route with submarine cables manufactured at another factory, cable laying that requires expensive charter charges reduces the occupation time of the ship and economically lays submarine cables. Therefore, the construction period of the submarine cable can be shortened by at least 1/2 in the submarine cable manufacturing period.

(3) In comparison with the method of laying a water-bottom cable of the invention of the already filed invention, the completion period for laying the water-bottom cable is the embodiment described in the section of the embodiment.
In the case of (1), the shortening amount is the smallest, and in the case of the example (2), the case of the example (3) is the largest. The reason for this is that the submarine cable can be continuously laid along the cable route without stopping the progress of the submarine cable laying ship. Half the length can be transferred from the first laying ship to the second laying ship, which can shorten the number of days.

Since the present invention has the above effects, according to the present invention, the subsea cable construction period of the submarine cable is shortened, the navigation of the water area navigation vessel is less likely to be hindered, and the submarine cable is shortened in a short time. It can be installed on the ground, and its industrial and economic effects are remarkable.

In addition, according to the already filed invention, when the laying route length is longer than the manufacturable length, a factory joint with a special flexibility that can sufficiently withstand the bending and twisting received by the cable immediately before the step of applying the normal wiring After that, it was necessary to lengthen the cable length by fitting the garment to withstand laying tension and external damage according to the factory joint. This requires advanced technology, expensive materials and a long time,
Even after that, special attention was needed until the completion of the installation in the factory joint. In the present application, for example, it is possible to apply a joint prepared as much as possible in a prefabricated type just like the connection portion of a land cable immediately before installation, and thereafter, it is possible to complete the installation with almost no bending or twisting. It also has very favorable effects on shortening the construction period, ease of construction, and reliability.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view in the case of laying a submarine cable on a submarine cable laying route according to the present invention, and FIGS. 2 to 4 are schematic side views of a main part of the embodiment for explaining the constitution and operation of the present invention, respectively. FIG. 5 is a bottom view of the bottom of the water bottom cable connecting portion cable in the embodiment shown in FIG. m ... Dividing point of submarine cable laying route, 1, 2 ... Submarine cable laying vessel, 3 ... Submarine cable connection dedicated vessel, C
₁ , C ₂ ...... water bottom laying cable, 1 ′, 1 ″ ... water bottom laying cable guide device, 2 ′, 2 ″ ... Yagura and cable connection work table, J ... cable end connection part.

Claims (1)

[Claims] 1. A submarine cable laying route, wherein two laying vessels each carrying a cable length obtained by dividing the route into two are routed to a dividing point of the laying route, and the cables are connected at the dividing point. A method of laying a submarine cable, characterized in that both ships proceed in the opposite directions to lay each other. "