In case of simultaneous operation of submarine cable laying and burial, KCS uses a cable burying machine, PLOW.
The cable burying machine, PLOW buries cables, repeaters and cable joint boxes in order to protect them from fishing equipment or anchors of large vessels.
The cable burying machine is a special robot which is towed by a mother vessel, and carries out the simultaneous laying and burial of the submarine cables.
It is, like MARCAS-III or MARCAS-IV, supplied electric power from the mother vessel via an umbilical cable, and remotely operated from the mother vessel based on the data from the still camera and sonar on it.
This type of cable burying machine is called "PLOW(PLOUGH)", since it digs a trench by the structure like a plow.
The KDDI PACIFIC LINK is equipped with PLOW-II. Its operating maximum depth is 1,500 meters, and the maximum burial depth is 3 meters. PLOW-II is mainly used for the submarine cable installation.
PLOW-II can perform the submarine cable laying promptly and effectively, since it carries out the cable laying and burial at the same time. By controlling the posture, and additionally using the waterjet in the shallower area than 200 meters, PLOW-II buries the submarine cable 3 meters under the seabed.
PLOW-II Operating Scene
1. For the cable laying and burial, PLOW-II is lifted up by the A-frame of the mother vessel, and is paid out overboard.
2. It is stored in the stern when it is not used.
In the shallower water area than 1,500 meters, the submarine cables are, for protection from damages by fishing activities etc., laid and buried simultaneously by PLOW-II, which is towed by the mother vessel, and digs a trench of 1 to 3 meters on the seabed .
The cable burial of maximum 3 meters is possible by the vertical plowshare and waterjet.
In case that PLOW-II is difficult to use due to a steep slope of the seabed, or because of the reburial of the cables, the self-propelled underwater robot, MARCAS-III or MARCAS-IV is used instead.
In June, 2008, PLOW-II was engaged in the cable burial in the shallow water section of RJCN submarine cable network which connects Japan and Russia .