What is a Cable Laying Ship?

Introduction to Cable Laying Ship

A cable-laying ship or cable layer is a vessel used to lay cables underwater on the ocean or seabed. The cables are laid for several purposes, including data and electricity transmission, military reasons, etc.

These ships can be identified by their massive pulley wheels onboard, which guide a cable over the cable layer’s bow or stern. The earliest cable-laying ships had bow sheaves, but the newest ones come with only stern sheaves.

The first Transatlantic Telegraph line was constructed in 1857 and 1858, allowing telecommunications between Europe and North America. In 1866, the SS Great Eastern successfully laid two transatlantic cable lines, a milestone for that time.

Features of Modern Cable Laying Ships

Cable-laying ships are powerful vessels built to be stable and highly manoeuvrable. As cable laying isn’t done throughout the year, these ships also function as research vessels, collecting data about the ocean and seas. Sometimes, they also sit at port for long periods.

Modern Cable Layers are of two kinds: cable repair vessels and cable-laying ones. The former are small and highly manoeuvrable. Their main task is to fix or repair broken underwater cables, while the latter are bigger, less manoeuvrable, and built to lay new cables.

The latest cable layers are, in fact, a combination of cable repair and cable-laying ships. For instance, the USNS Zeus is a U.S. Navy vessel that can lay new cables and repair broken cables. With two diesel-electric engines, the vessel can lay about 1600 kilometres of cables and has a speed of around 15 knots.

The biggest cable-laying ships can lay around 9000 tonnes and more of cables.

Modern cable-laying ships weigh more than 11,000 tonnes and can lay two to three lines of cable. Cable layers generally do not operate near the coastline or the shores, as it is difficult for them to operate in shallow waters.

Special Equipment onboard Cable Laying Ships

Cable-laying ships have special equipment to aid them in laying underwater cables.

The machinery and laying equipment are hydraulic, which means they are operated by water or oil and pneumatic or operated by air. Cables are coiled and stored in the ship’s hold.

These ships have a grapple system to pull wrongly laid or damaged cables from the seafloor. The grapples are connected to the cable layer with synthetic rope, ensuring they are strong enough. The linear cable engine helps pull back the cable.

The linear cable engine is used to lay cable on the seafloor and retrieve damaged cable by reversing it. It can handle around 240 metres of cable every 60 seconds. It has powerful brakes to control the speed of cable laying or halt when required.

Cable layers operate at a speed of around 8 knots while at work to ensure the cable is laid correctly and to adjust the cable’s position. The position is recorded so the cable can be found and repaired if needed in the future.

Another system on cable layers is a fleeting drum, which guides the cable into the linear cable engine.

Ploughs under the cable-laying ship enable burying the cable at least 3 feet under the ocean bed to ensure it remains safe from fishing vessels that drag their nets to catch fish.

The DP2 system makes it possible for the cable layer to stay in place above the cable route while laying undersea cables.

The dynamic position system allows them to operate in harsh conditions while offering protection and stability to the ship. These vessels can also be fitted with a remotely operated vehicle.

They also have a damage control system, which is handy if the cable has been damaged.

Cable-Laying in Different Areas

Directional drilling is employed to install underwater cables near the coast. For this, conduits are laid under the ground or under reefs.

When laying cables in shallow water areas where fishing and water sports are common, cables must be buried deep to prevent them from being damaged by a fishing trawler.

If the ocean bed has a rocky or hard surface and burying the cable is difficult, armoured cables are used. The armour prevents anchors and other hazards from tearing or damaging the cables.

When cables are laid in the deep ocean, it is known that they won’t be damaged by vessels; therefore, they are laid on the ocean floor.

Conclusion

More than overhead cable networking, underwater cable lines have far more reachability and penetrability. They are not greatly affected by natural calamities, unlike their land counterparts, which can be damaged during rain or snow.

Furthermore, since underwater cable lines are laid in the deepest part of the ocean or sea, they don’t require continuous maintenance, like land cables.

You might also like to read-

• 5 Fastest Submarines in the World
• 10 Largest Hospital Ships In The World
• Top 5 Biggest Bulk Carriers In the World
• What are Offshore Vessels?
• What Are Nuclear Vessels?

About Author

Zahra is an alumna of Miranda House, University of Delhi. She is an avid writer, possessing immaculate research and editing skills. Author of several academic papers, she has also worked as a freelance writer, producing many technical, creative and marketing pieces. A true aesthete at heart, she loves books a little more than anything else.

Read More Articles By This Author >