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Secrets of Submarine Cables - Transmitting 99 percent of all international data!

  • KogaIn areas where the depth of water is less than 1,000 meters, we bury the submarine cable in most cases.
  • MitaYou say "shallow," but a depth of 1,000 meters sounds deep to me. I know you don't do hand digging. Could you tell us how you bury the cable?
  • KogaYes. We use an instrument called a “cable plow” capable of seabed digging. This cable plow has a part that works like a hoe used for ploughing fields. We plough the "hoe" in the sea bed and drag the plow behind the cable ship. That creates a groove, and we lay down the submarine cable in that groove. After that, the current of the ocean covers the groove with sand, saving us the work of burying the cable.

Photo: Cable plowCable plow

  • MitaI see. It's well designed to save labor. Ploughing the ocean floor is an interesting idea.
  • KogaYou could say that.

Picture: Conceptual diagram of the submarine cable systemConceptual diagram of the submarine cable system

  • MitaNow, please tell us how you lay a submarine cable in the ocean. You said earlier that the deepest part of the submarine cable is 8,000 meters below sea level. But throwing in a cable to a depth of 8,000 meters from aboard a ship sounds like a godlike act.
  • KogaYes. It's like aiming at a certain point at the foot of Mt. Everest from its summit. Besides, we need to take into consideration a number of factors, such as the ocean current, when throwing in a submarine cable. So it's safe to say that it takes very sophisticated technology.
  • MitaI was a poor player at any sports using a ball in physical education class, so it's just beyond my imagination. Unbelievable.
  • KogaThere's more to surprise you. Actually, we have to aim over a much longer distance.
  • MitaWhat do you mean?
  • KogaThe ship used for laying submarine cable is not anchored. The ship moves as we throw in the cable, so the submarine cable sinks at an angle. That means the distance to the ocean floor becomes longer - twice as long, actually. If you want to lay cable on a sea bed 8,000 meters below sea level, you need to aim over a distance about 16,000 meters behind you.

Picture:Conceptual diagram of cable installationConceptual diagram of cable installation

  • MitaJust thinking about the height of Mt. Everest is already mind-boggling to me, and you're telling me it's twice as long? Well, 16,000 meters is 16 kilometers. So it's like aiming at the intersection in front of the railway station in Kawasaki, Kanagawa Prefecture, from a height of 8,000 meters above Tokyo Station. I just can't imagine it. The skill of those workers engaged in submarine cable installation is really amazing!
  • KogaI'm glad to hear that. This kind of work wouldn't be possible without skilled professionals on the ocean floor and current. Can I talk a bit more about this?
  • MitaYes. Of course. Please.
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