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How subsea cables are laid
11 Aug 2018

How subsea cables are laid


Laying cables undersea is a fascinating and daunting task. Every year, men and women all around the world lay thousands of miles of subsea cable, which has made it possible for us to communicate at an affordable price. But with thousands of miles of cables placed under sea, it is imperative that the personnel designated to the task take necessary measures to make it happen.

Specially designed cable ships carry up to 2000 km length of submarine cables. Special amplifiers are spaced about 25 miles apart within these undersea cables to boost the voltage signal carried in them in order to prevent the losses in the cable. A plough is used to lay the cable inside a trench instead of leaving it on the sea bed. In case an obstruction occurs while laying cables on the seabed, a length of cable can be recovered and re-laid on a separate route to avoid blockage.

Depending upon the equipment on-board these cable ships, the type of plough used, the sea conditions, and the ocean bed beneath the cable, the ships can lay anywhere around 100-200 km of cables per day.

Laying subsea cables is a very scientific process and there are four different approaches involved:

1.    Shoreline

This process involves laying subsea cable under the beach and any near-shore reef using directional drilling techniques.

2.    Shallow Waters

Shallow waters often involves fishing areas, so while passing through soft bottom areas, ideal for ship anchoring, trawling and other bottom-fishing techniques, the cable is buried typically to be protected from the fishing gear.

3.    Hard-bottom Area

Ploughing a cable under a hard bottom area is impractical, so armoured cables are used while placing the cables through these areas to prevent lateral movements.

4.    Deep Ocean

Deep ocean refers to the areas with bottom fishing gear or anchoring. In these areas, the underwater cables are laid out flat on the ocean bed. 

KBA Marine - Delivering wide-ranging & world class marine services

KBA Marine is fully compliant to local and international safety and health standards, and our team of professional tenders, divers, dive supervisors, diver medical technicians and other support personnel are dedicated to safety and getting the job done right. We invest in the right equipment and training that is fully compliant to ensure safety in all diving operations. 

All our divers are certified in accordance with the Singapore SS511 Commercial Diving Code of Practice, such as LSP ISO 29990 Commercial Diver training and certification or equivalent (HSE UK, ADAS) and they also undergo our in-house safety and task training programs to enhance their skills.

For more information on subsea cable laying, please contact us.

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