Submarine Cables

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Submarine cables

Laying of cables in the oceans of our world is a fascinating business. Real men and women toil long and tedious hours to make this possible.

Submarine cables are laid down by using specially modified ships (sometimes even purpose built ships) that carry the submarine cable on board and slowly lay it out on the seabed as per the charts/plans given by the cable operator. The ships can carry with them up to 2,000 kilometers length of cable.

Depending on the equipment on-board the cable-ship, the type of plough used, the sea conditions and the ocean-bed where the cable is being laid-down, cable ships can do anywhere from 100-150km of cable laying per day. Newer ships and ploughs now do about 200 km of cable laying per day.

The ships are commonly referred to as cable-layers or cable-ships.

The cables are specially constructed for submarine operations as they have to endure harsh conditions as well as pressure.

Cable Dissection

Here is what a typical 3-D cross-sectional cut-out of a submarine cable looks like:
1.Polyethylene
2."Mylar" tape
3.Stranded metal (steel) wires
4.Aluminum water barrier
5.Polycarbonate
6.Copper or aluminum tube
7.Petroleum jelly
8.Optical fibers

These fibre optic cables carry DWDM (http://en.wikipedia.org/wiki/Wav...) laser signals ( TCP/IP packets etc. ) at a rate of terabytes per second. They use optical repeaters to strengthen the signal which attenuates over long distances. These are powered by copper cables shown above.

They have a decade lifespan and costs vary (depending on the length of the cable). Typical costs for projects are anywhere from US$ 100 Million to $500 Million.

You might also want to read Do private telecommunications companies own the undersea cables that connect the internet across continents?

We don't use satellites because they can't carry terabytes of data for less than a billion dollars per communication line.

In real-life the cable would look like this:

Here is another look...

Depending on where the cable is being laid, it might differ in thickness. Thinner cable systems are used for shallower ocean depths, whilst thicker cables are used for deep ocean beds, typical up to 20,000 feet. Such cables are able to withstand pressure from 12,000 lbs/square-inch to 22,000 lbs/square-inch (this is necessary because of the extreme pressures in the deep ocean beds.

Submarine cable laying process starts from the Landing Station, where a long cable section is attached (connected) to the landing-point and then extended out to a few miles in the sea. This end is connected to the cable on the ship and then the ship starts its cable laying process (a simple representation of this process can be seen/read here: http://www.k-kcs.co.jp/english/s...).

This is how the cable approaching the landing station looks like (notice the cable laying ship in the horizon):

Depending on the geography of where the cable is laid out, the cable coming in from the ocean to the landing station might be advertised or not. Most of the time, it is buried as much as it can be and warning signs are placed so as to inform everyone that a submarine cable is landing ashore. Most of the time cable consortium companies try to hide the cable as much as they can, so that only those who need to know, are informed of the exact route of the cable. This would include municipalities, port authorities and shipping companies.

The market for submarine cables is dominated by Europe (UK, Italy, France, Germany) and a bit by Japan. US is overall a small player when compared to the others, as US itself did not have much need to expand cables to other countries, as much as the other countries had a need to connect to the US.

The ships, which are specialized, are almost all owned by the submarine cable consortium or manufacturers. These ships are stationed at various points along where the cable extends to ensure that in the event of a...
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