The C/S ‘Nexans Skagerrak’, already one of the world’s most advanced cable ships, has had its capabilities quite literally extended at Cammell Laird during a major conversion in 2010.
The €8m, two month, fast track contract was carried out in Birkenhead and saw the ship come out better equipped, and 12.5m longer.
The Skagerrak was the first purpose built ship to be designed specifically for the transport and installation of submarine high voltage power cables and umbilicals. To date, there are only two vessels of this kind in the world.
It features a 7,000 ton capacity, 29m diameter turntable, a computer based laying control system and the latest dynamic positioning system. It can also deploy Nexans’ specialist Capjet ROV trenching systems for cable burial operations.
The ship was placed inside Cammell Laird’s largest facility. The company’s No.5 Dock measures 290m by 44m, needed to accommodate Skagerrak’s 32m beam.
The 500 ton extension was constructed in Cammell Laird’s massive hall on the yard’s south side. However, it then had to be transported a quarter of a mile down the Campbeltown Road, a public highway. Alf Povall, planning manager on the project, said: ‘The street lights had to be turned around to allow the extension to travel through.’ The council had to be informed and police notified to close the road off to the public that day.
The ALE low loaders that transported the extension were further used to separate two halves of the ship in the dock, and then the extension was dropped in and aligned by using a specially hired Sarens crane. The cut and separation took six days, explained Mr Povall, and when finished, the insertion of the 12.5m pre-fabricated hull section increased the ship’s overall length to 112.25m.
Mr Povall said that at the same time the extension was being fabricated, an accommodation module with 17 cabins was also being constructed and completely outfitted, taking the total number of single cabins on board to 60. Located on top of this is now a new work and cable repair deck, complete with cable handling equipment, that has increased on the on deck storage capacity to some 2,000 m2 (up from 900 m2). The upgrade has increased the ship’s deadweight from 7,886 tons to 9,373 tons.
The conversion and upgrade has extended the vessels service life and increased its autonomy while at sea. It has also increased the Nexans Skagerrak’s capability to carry out even larger scale power cable and umbilical installation projects.