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Linking Japan and South-East Asia! - the new “SJC” submarine cable

  • MiwaOCC has optical fiber wound inside an iron tube by using a unique technology called the "three-piece iron" structure in which three iron pieces are combined together. When building an submarine cable, you usually put optical fiber on an iron tape, roll the tape into tubular shape and weld it. But when you weld the iron, the heat is transmitted to the optical fiber, which can change the properties of this important material. In the three-piece iron structure, by contrast, the optical fiber is shielded by the arcs of three iron pieces that are combined to form a ring. This allows you to build a submarine cable without welding the iron, so there is no risk of the optical fiber properties being changed.

  • MitaYou pay attention to very high levels of detail. It's an amazing feat that they create an iron tube of a submarine cable that is thousands of kilometers long without any gaps.
  • MiwaThat's the technology that OCC takes pride in. Would you like to take a look at the manufacturing plant?
  • MitaI'd love to!

Picture: Sheathing iron wire is wound around the submarine cable.Sheathing iron wire is wound around the submarine cable.

  • MiwaI talked earlier about putting optical fiber inside the three-piece iron structure. Thereafter, they wind iron and copper around the iron tube made up of the three iron pieces and apply a coating of polyethylene as a surface finish. Here, they are winding sheathing iron wire to protect the submarine cable from anchors, dragnets and other obstacles.
  • MitaA huge machine is rotating at high speed, and the noise is very loud.
  • MiwaThat's right. The thin submarine cable is passed through the center of the machine, and the machine rotates at high speed to wind iron wire around the cable. This method is primitive but the most effective. This plant is located next to a harbor, so the submarine cable manufactured here is then taken to the cable ship on a roller conveyor.

Submarine cable (white cable seen in the left side of the photo) brought on a roller conveyor to a cable ship

  • MitaOh, you're right. I see the manufactured submarine cable being taken on a roller conveyor.
  • MiwaThe other end of this roller conveyor is connected to the cable tank of the cable ship used for submarine cable installation. Let's go and see.
  • MitaWow, so this is the inside of the ship for submarine cable installation. There's a large tank into which the submarine cable brought from the plant is being fed. Is this the cable tank?

Huge cable tank containing the submarine cable

  • MiwaYes. The cable tank is about 8 meters high and about 15 meters across. It has an area as wide as a basketball court. The ship for the SJC project has two tanks, and we load about 2,500 kilometers of submarine cable into each of them. That amounts to about 5,000 kilometers in total. Loading the cable into one tank takes about three weeks, with personnel working on 24-hour shifts.
  • MitaThree weeks! That shows just how long the cable is. I mean no offense, but the work looks a bit simple. Is winding the cable with no slack difficult?
  • MiwaAll the personnel working at the bottom of the tank are seasoned skilled workers. According to what I've heard, new recruits are not allowed to participate in the loading work because it is difficult for them.
  • MitaSo winding the submarine cable in the tank requires long years of experience!
  • MiwaAfter the submarine cable is manufactured and loaded as we have seen just now, cable laying work starts at the cable landing station. I'm going to see this cable landing next week. How about you, Ms. Mita?
  • MitaOf course, I'll join you!
  • MiwaI knew you would.
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