Tag Archives: Subsea cables

How Do Subsea Cables Work?

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


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.

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 cables 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!

The Wonderful World of Undersea Cables – Mapped!

A couple of months ago, we blogged about the astounding global network of subsea cables that keep the world connected through the internet.

Underwater cables play an essential part in day-to-day life, yet very few people are actually aware of their existence. It’s difficult to describe the true scale of the network of offshore custom cables that power the internet in words, which is why we’re thankful for the this frankly jaw dropping map of the underwater cable network in 2013, produced by TeleGeography.

The map, which you can view either as a straightforward image in this post or in an excellent interactive format on the TeleGeography site, provides a truly fascinating insight into a network that not many people know about. The old-school map shows the precise location of every underwater cable in the world and the countries it connects, as well as cables planned for the near-future.

The map also provides a potted history of subsea cables with an impressive timeline illustrating the massive growth of the subsea cable network since the mid-90s – a boom that coincides with the explosion in worldwide internet usage. Particularly interesting is the recent development of underwater cables between Europe and sub-Saharan Africa, which only started emerging in 2008.

There is also a latency section, neatly set out in the manner of a star chart, illustrating the delay in the round trip data sent over the internet between two countries. If you’ve ever wondered why a site hosted in Australia takes longer to load than a site hosted in the US, here’s your answer!

We all take connectivity for granted, yet the map provides an interesting illustration of just how far our data has to travel. While the UK has direct undersea connections with the US, data sent to Japan, for example, has to embark on a cross-continent journey that would potentially take days for a person to complete. Data sent through underwater cables takes just a matter of seconds to arrive at it’s destination.

When you consider the amount of data being sent through these cables too, it becomes clear what a marvel of modern engineering subsea cables are. Well, we say modern – the first subsea cables were actually installed way back in the late 1800s, while most of the continents in the world were connected by the early 1900s! It’s fair to say that early cables weren’t quite as technologically advanced as the optic-fiber cables we use today but it says something for the effectiveness of underwater communication that we still rely on the technology for a completely different purpose over 100 years later!

For more information on how subsea cables are built and designed, take a look at our previous post on the subject or get in touch with Custom Designed Cables on 01204 658 784.

The Undersea Cables Which Power The Internet

In a Wi-Fi world, the internet is a fleeting, invisible force which links together all of our devices. Smartphones to desktops, futuristic fridges to television sets, everything is connected together without wires. But on a global scale, this is simply not true.

When it comes to communicating between London and Hong Kong, the information sent to your router might be wireless but from then on in, a series of interconnected cables transports everything across the world. The internet, in reality, is made possible thanks to the huge volume of underwater cables. While most assume that satellites are doing the heavy lifting, the bulk of information is sent along wired connections.

This is far cheaper and simpler than beaming data to space, a tool usually reserved for broadcasting. The fibre-optics which make our internet a reality are buried deep in the sea bed. They serve each and every continent, spread out like a submarine spider’s web. While the current crop of cables can carry a huge amount of data, our appetite is growing, as is a need for a fall back option should anything break.

The layout is designed to avoid fault zones which exist underwater and to deliver internet with the minimum amount of interference. There are issues, however, three quarters of which are down to external aggression (fishing, anchors from ships). Geological issues also pose a threat, with landslides, earthquakes and the moving tectonic plates all destabilising connections.

The 2011 Tsunami which struck Japan, for example, required quick work and rerouting in order to keep the country online. The more cables which route into the country, the better protected they are in such circumstances. Not all cables are created equal, with those found in the Atlantic capable of transmitting more data than those which run down the coast of East Africa.

Demand dictates performance and smaller markets lead to lower capacities in certain areas. The cables which cross the largest oceans can cost hundreds of millions of dollars. With the majority of landmasses connected, island nations and remote communities are still waiting for integration.

The main challenge now is maintenance. For those in western countries, the amount of connections provides almost seamless service. For locations such as Bangladesh, one cable going down can have a big impact. Additional connections, such as the large cable nearing completion between the USA and Mexico, will add further capacity in certain areas.

As internet traffic increases and bandwidth is ever more important, scaling the solutions already in place will be essential.