6 Things You Didn't Know About Submarine Cables

Vodafone Carrier Services is one of the world’s largest investors in submarine cables which reach more than 100 countries. Submarine cables are responsible for carrying the majority of the world’s data, but what else is there to know about these impressive pieces of technological infrastructure?

1. Nearly 100% of the world’s inter-continental traffic moves in the oceans

Telecommunication satellites were an important means of inter-continental communications from the 1970’s through to the 1990’s, when they were overtaken by high capacity fibre optical submarine cables as the principal means of communications on higher density routes. Fundamentally cables have significantly greater bandwidth (and power) and this drives a much lower cost per bit of transmission. This has allowed operators to offer much cheaper connectivity. Cables transmit data at 99.7% the speed of light and each fibre pair can support a transmission rate of 14 terabits/second. Satellites remain important for connecting remote or hard to reach places, but the majority of countries are now connected by optical fibre submarine cables.

2. The life expectancy of undersea cables is around 25 years

Submarine cables are designed to operate for 25 years before they require replacement. However, it is likely that many will operate for periods well in excess of this, unless a disruptive technology renders them obsolete. All cables are subject to damage from trawlers and anchor drags. When cables are broken, special repair ships are used in order to repair them. In situations where the damaged part of the cable is not too deep, engineers may use robots to bring cables to the surface for repair. In deeper water a grapnel is used to hook the cable and bring it to the surface.

3. The diameter varies from the size of a coffee cup, to that of a garden hose

Repeatered submarine cables contain between 2 and 8 fibre pairs, which are covered in a number of protective layers. Sections of cable running closest to the shore will usually be buried or if this is not possible, armoured to protect it from fishing and anchor drags. Armoured cable can be up to 7.5 cm thick. At depths greater than 1500 metres the cable closely resembles a garden hose in diameter.

4. Cables are not reinforced to withstand shark bites

This common myth has found itself all over the internet in recent years due to a video of a shark biting a cable that went viral. Whilst sharks might take the occasional bite, there is only one confirmed case of a shark causing damage. The real reasons that the cables need to be reinforced to such a high degree include anchors, fishing nets, and natural phenomenon such as underwater volcanic activity.

5. Submarine cables are lowered onto the sea bed

Cables follow the terrain of the seabed which is as varied as the land around us. Interestingly, the deepest reaches of the undersea cable between Japan and the U.S. lies about 8,000 meters below sea level. That is further below sea level than Mount Everest is above!

6. Economies rely on submarine cables

One recent study by the University of Huddersfield in Yorkshire, UK, concluded that at least £65 billion of UK economic activity per year relies on the subsea cable industry. This demonstrates the scale and importance of international communications to governments, businesses and individuals in the UK and worldwide!

To find out more about the submarine cables that Vodafone Carrier Services offers capacity on, drop us a message to CarrierServices@vodafone.com

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