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20,000 leagues under the sea... a trawler hit an internet cable and sent broadband into meltdown

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A specialist repair ship, the Pierre de Fermat, was dispatched to the Irish Sea (below) where an ROV was then submerged to locate and damaged cable

A specialist repair ship, the Pierre de Fermat, was dispatched to the Irish Sea (below) where an ROV was then submerged to locate and damaged cable

Huge internet cables run from the shore under the sea, connecting countries and continents

Huge internet cables run from the shore under the sea, connecting countries and continents

The splicing procedure which mends the two joints

The splicing procedure which mends the two joints

Virgin Media customers were affected, with some experiencing a slowdown in broadband

Virgin Media customers were affected, with some experiencing a slowdown in broadband

Getty Images/iStockphoto

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A specialist repair ship, the Pierre de Fermat, was dispatched to the Irish Sea (below) where an ROV was then submerged to locate and damaged cable

Engineers have revealed how crews battled round the clock to repair a submarine broadband cable that broke halfway across the Irish Sea earlier this month.

A Remotely Operated Vehicle (ROV) or submarine robot was sent down to inspect and retrieve the broken cable before it was spliced back together by specialists on the ship.

It's thought that a fishing trawler or ship's anchor was the most likely culprit for the cable break, which caused broadband speeds for customers to slow down earlier this month.

The breakage sparked a two-week operation, with two ships' crews battling stormy conditions to restore connectivity.

A team of 30 people from across Virgin Media, including engineers, submarine fibre optic specialists and support staff, was assembled to repair the break.

Specialist repair ship, the Pierre de Fermat, sailed from France to Portland in England to collect spare cables, materials and the crew before heading for the Irish Sea. Tests were carried out on both sides of the Irish Sea to trace the connection and locate the damage, with an electric tone sent down the cable to find the breakage point.

Peter Jamieson, a principal engineer from Virgin Media's core network engineering and planning department, said it took about four days of working round the clock to carry out the repairs at the scene.

"It was most likely caused by a fishing vessel or a ship's anchor," he said.

"We did have a few days of bad weather which caused a few hours of down time.

"But the repair ship is state-of-the-art and only in the severest weather would it not be able to run.

"The ROV is a really important piece of equipment. It has infra-red sensors and robotic claws which it uses to inspect the cables and damage. If necessary, it can bring the cable up to get it repaired.

"Where our cable was damaged it was silty clay - over towards the eastern side of the Irish Sea it is more rocky.

"The cable had taken a hefty knock.

"To be repaired it has to be in two pieces, so what the ROV does is cut the cables, brings one side up and then brings the other side up.

"Then we splice in a piece of cable into the middle.

"It took about four days to do the whole repair operation. There have to be two joints and each joint takes 24 hours. There is very tight quality control - we do it methodically and we do it right.

"Thankfully, this doesn't happen very often - this is only the second incidence of damage to an undersea cable in seven years."

The 4,000-tonne Pierre de Fermat is specifically designed to manage the installation and maintenance of all kinds of submarine cables, including fibre optic cables.

The ship has GPS systems linked to manoeuvrable thrusters so it can stay in the same position regardless of currents, wind and waves, allowing a new piece of cable to be jointed on safely and securely.

Some 97% of the world's communications is carried by submarine cables.

Virgin Media operates two submarine fibre optic cables, one between England and Ireland and the other between Scotland and Northern Ireland.


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