Rocks & mirror
Encyclopedia of Marine and Energy Technology

Cable handling equipment, cable machinery


Installation and maintenance of a submarine cable is a complex operation requiring sophisticated tools. The primary cable handling equipment of a typical cable-layer is designed to load cable from ashore into cable tanks and discharge it from the tanks onto the seabed. Central to effective cable handling is the wheel pair – two tires on wheel rims mounted on hydraulically operated arms opposed to each other. These arms enable the driving wheels to grip the cable, joints and transitions as they pass through.

Cable Transporter – A highly versatile, mobile or fixed, self-contained cable handling machine, that uses a pair, or pairs, of motorised wheels to transfer cable or rope between the ship and the storage tanks.

Linear Cable Engines (LCE) are of a modular construction assembled in sections of wheel pair assemblies. They are arranged as bi-directional systems for both cable laying and repair operations, whilst posing minimum risk to the cable or repeaters. Each individual wheel pair is controlled by fully synchronising speed, wheel opening and pressure/squeeze onto the cables. At very low cable tension in shallow waters, the sensitive control systems will automatically reduce the drive unit torque, reducing the risk of cable slip. Typical combinations of up to 18-36 wheel pairs are available, depending on required pulling force, available deck space or requirements of specific cable types.

At the outboard end of the LCE, a heavy-duty hydraulically-operated cable gripper is fitted, sometimes referred to as a stonker. In case of sudden outboard tension or catastrophic failure of the LCE, its jaws can close on the cable stopping the cable from running overboard.

Draw Off- Hold Back Engine (DOHB) – A back tensioning engine usually installed at the aft end of the cable ship, forward of the Cable Drum Engine (CDE). It is used together with the CDE for cable repair work; it can also be used independently for cable transport duties. DOHB are usually four-wheel pairs, one after the other mounted on a traversing frame. The first and the second wheel pairs are separated from the third and fourth wheel pairs; when a joint or repeater is passing through you will have at least one wheel pair at any time gripping the cable either before or after the repeater.