Damage, which may not be fixed for three weeks, caused 20% slowdown in countries including Kenya, Rwanda and Ethiopia

This article is more than 8 years old

This article is more than 8 years old

The old theory that a butterly flapping its wings can cause a hurricane on the other side of the world may be somewhat far-fetched. But that a ship dropping anchor can disrupt the lives of millions has become painfully evident.

That is what happened off the Kenyan coast when, by unlucky chance, an anchor scored a direct hit on an underwater fibre-optic cable.

The knock-on effect is a predicted 20% slowdown in internet speeds in Kenya, Rwanda, Burundi, Tanzania, Ethiopia and South Sudan, the BBC reported.

The offending ship was waiting to enter the port of Mombasa at the weekend when it halted in a restricted area.

The damaged cable, owned by The East African Marine Systems (Teams) – in which the Kenyan government has a share – is one of three serving east Africa. It could take up to three weeks to repair.

Joel Tanui, general manager of Teams, said: "We wish to notify all our stakeholders of ongoing emergency repair works and apologise unreservedly for any inconvenience this may cause. The cable should be fully operational within the next three weeks."

Fibre-optic cables are typically composed of about four strands, each the diameter of a human hair and capable of carrying millions of phone calls and data connections simultaneously. They are protected by an armour of thick steel.

East Africa undersea cable map

Teams will send remote-controlled submarines to assess the damage and raise the cables to the ocean surface, where specialist engineers will carry out repairs.

The cable links the region to the United Arab Emirates. Internet service providers and mobile phone operators have rerouted to a 10,625-mile cable provided by Seacom, which since 2009 has linked east Africa to Europe, India and South Africa, putting pressure on its bandwidth capacity.

Eassy, another connection activated in July 2010, links countries along the east African coast.

Toby Shapshak, editor of Stuff magazine in South Africa, and author of a forthcoming book on innovation in Africa, said: "Sadly, this reveals how fragile the physical infrastructure for Africa's internet access is. Because of the distances involved, the primary connections, in the main, are undersea cables which can be easily disrupted by a careless anchor.

He added: "But it does show there has been progress in African connectivity. Luckily, we've moved on from single cables, so there is at least some redundancy when events like this occur. Losing 20% of East Africa's connectivity is a lot better than losing all of it, as would've been the case had this happened a few years ago.

"The enormous cost of laying the cables - and the delays in fixing them, as this shows - is part of the reason internet access in Africa remains expensive."

The slowdown has caused irritation to east Africa's growing band of Facebook and Twitter users, as well as the rapidly growing hub of internet startup companies in Kenya.

Internet subscriptions in the country increased from 1.8m to 3.1m in the first year after the information pipelines arrived. There was also a huge growth in e-commerce.

Users vented their frustration on Twitter. Harry Karanja, posting as @startupkenya, wrote: "Looks like all isps have now routed their traffic to Seacom. Internet is crawling!"

Another tweeter, @shuhi said: "I'm officially kissing YouTube goodbye till this whole Seacom maneno is sorted."