MAPPING THE OCEAN

SEACOM launched Africa's first broadband submarine cable system along the continent's eastern and southern coasts back in 2009. PM met up with SEACOM's CEO, Byron Clatterbuck, to chat about everything to do with the cable that's lying beneath the ocean's surface.

Popular Mechanics: How would you describe a subsea cable to someone who has never seen one before? How do you design a cable of this magnitude?

Byron under the Clatterbuck: ocean and rests It’s really on the a giant seabed. hose When that you’re goes going to build something such as a subsea cable, you need to understand where you’re building it, where it’s going to land, and where it’s going to lie on the sea bottom. Once the cable’s been constructed, sometimes it takes the ship up to a month just to coil the cable, before heading out of harbour to go and lay the cable.

PM: It's a huge project – can you give us some details about its scope?

BC: The SEACOM cable took more than two years to build and cost almost half a billion US dollars when all was said and done. It takes a long time to construct the cable, from someone’s conceptual idea, right through to getting it working.

PM: How do you prevent cable damage?

BC: Cable outages are generally caused by physical aggression, usually in the form of inadvertent attacks. We chart the position of our cables very carefully so that everyone involved in shipping, fishing, the coastguard or navy knows exactly where they lie on the seabed and in shallow water. We emphasise that no one must drop anchor anywhere near to those locations.

PM: How do you monitor the cables?

BC: Our cables have sensors that alert us when ships are positioned over them. And the reason we need to know this is because if a ship is stationary in one area, it might be involved in fishing, and there’s a higher likelihood that it’s going to drop an anchor. If a ship drops anchor and there’s a storm, there’s a very high chance that it will drag our cable. If you look at the history of cable breaks off the coast of Africa, almost 90 per cent were caused by ship anchors.

PM: How difficult is it to fix a subsea cable?

BC: We work on a zonal model. We have ships that are based, for example, in Djibouti, that could cover the Red Sea. We have a ship based in Egypt that covers the Mediterranean Sea. Each ship is on a retainer and has spares specifically for the SEACOM cable, because it’s built to order. When our cable is cut, there’s an immediate signal; we know it’s been cut and we know approximately where it’s been cut. What we don’t know is the severity of the cut, but we’re able to immediately dispatch a ship carrying spares to repair the cable as quickly as possible.

PM: Are sharks ever a problem? Have they been known to bite through cables?

BC: protect In shallow it with an water, armoured we generally coating. wrap Deep-sea the cable cables and might resemble a regular garden hose but, in the vicinity of the shore, it’s a bit more like a drainpipe gutter. This prevents the cable from being severed in the shallow water. There is in fact a lot of direct current – DC current – flowing through subsea cables, so if a shark actually happened to penetrate it, it would most likely be electrocuted. But, generally speaking, it’s humans who cause the most disruptions with our cables.