Have you ever wondered how you can make a phone call to a country thousands of miles away instantly? Or establish an internet connection strong and quick enough to video call someone in a far-flung land? The answer is an incredible undersea network of data communication cables spanning continents, delivering terabytes of data every single second. Laid under oceans between land-based stations, these custom cables keep the world connected day and night. But the sea is a rough place for even the most hardy of souls; so how exactly do these cables withstand the harsh conditions of the high seas and still manage to deliver unfaltering data communication for us all? Anatomy of a Subsea Cable image source: Wikipedia The demands placed upon subsea cables make them a unique prospect in the cable industry and as such, cable designers have worked for years (and are still working) to create the ideal cable for standing up to the harsh conditions and underwater pressure of the ocean while also delivering a reliable connection. The above diagram illustrates a subsection of the average subsea cable. As you can see, the cable is shielded by a thick layer of material (numbered 1) – usually polythene – in order to protect the cable from underwater damage. Ensuring that a custom cable features adequate cable shielding is an absolutely essential part of building a subsea cable. In fact, protecting the cable goes beyond this outer layer of polythene; inside the cable, we can see stranded metal wires (3), an aluminium water barrier (4), polycarbonate (5), metal tubing (6) and a layer of petroleum jelly. Basically, the bulk of the cable exists to protect the precious fiber optics – responsible for the transmission of data – inside! Optical repeaters are also used to strengthen the signal of the cable across long distances. These repeaters are powered by a constant and substantial direct current, making these cables an extremely dangerous prospect should you happen to accidently cut into one! The thickness of a subsea cable will also vary depending on the depth in which it is to be laid in order to protect it from the effects of underwater pressure. Laying a Subsea Cable Laying the cables that power global communication is an arduous and time-consuming task. Specialist vessels are used to lay cables between one land-based station to another. Using a deepsea plough-type device, the vessels follow the route of the cable, laying it as they travel to the final destination. The average cable laying operation can cost millions of pounds to complete and has to be carried out – on average – about once a decade. The Importance of Subsea Cables Subsea cables are an essential part of our global society yet many people aren’t even aware that this international data communication network exists. On the rare occasions the subsea cable network appears on the news, it’s because of a failure in the network. For example, an accident involving a ship cutting a cable and thus knocking half of the Middle East offline (also referred to as the Alexandria accident) in 2009 received widespread coverage and produced ample evidence for just how important subsea cables are. These kinds of incidents are thankfully rare, as the design of subsea cables mean they are relatively safe from potential undersea cutting hazards. Most subsea cables are also buried, so the danger of a shark biting through a cable a la ‘Jaws 2’ is pretty slim. So the next time you’re making a Skype call or watching a hilarious video on a Chinese video website, give a thought to the underground network of custom cables powering that process! If you’re interested in developing your own underwater cables – on a global or smaller scale – then get in touch with the specialists at Custom Designed Cables; no matter what the job, we’ve got the solution!