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The Ile de Batz is one of three dedicated ships Alcatel-Lucent uses to lay the submarine fibre-optic cables that carry broadband connectivity across the oceans.
The ship is usually based in Calais, but is in Greenwich now, picking up components from Alcatel-Lucent's factory. On Thursday, the telecommunications infrastructure firm invited ZDNet UK to see the factory and the ship, and have a look at a vital part of the global internet that's normally hidden by miles of water.
The Ile de Batz usually spends between 30-40 days at sea on each voyage. It can lay up to 200km of cable per day, in normal conditions, to a depth of about 8km. That cable and its components is expected to have a lifespan of around 25 years.
Here, a member of the ship's crew shows off the various thicknesses of cable that are deployed from the Ile de Batz.
The different sizes are used at different depths, although surprisingly the larger diameters are used closer to the surface. The top example in this picture is the lightweight cable that Alcatel-Lucent uses in very deep oceans, where ships' anchors pose no threat. The shallower the waters, the more heavily-armoured the cable needs to be, as depicted in this progression of thickness.
If cut, the cable can be repaired — Alcatel-Lucent has more ships on standby around the world for this purpose — but each reconnection degrades the system gain of the cable. The system is designed with enough headroom to tolerate a certain number of repairs.