Subocean’s Mike Daniels told MJ that the new deck equipment is needed to meet the growing demands of the offshore wind energy sector. It takes 300mm of 132kV power cable, the kind that exports the power from offshore wind farms back to the onshore stations, rather than the smaller diameter cable that links the arrays together.
‘That’s approximately about 55 or 60km of cable on the reel at any one time,’ said Daniels. The company is getting its money’s worth, as the Discoverer is presently working on the Rhyl Flats wind farm, moving onto Greater Gabbard next month, and then going onto Thanet later in the year.
The carousel, built especially for Subocean by Parkburn Precision Handling, has an electric drive system, two five ton tensioners and a programmable logic controller to regulate the release. It is largely constructed from welded I-beam sections, with the ring wheels made out of a Hardox wear resistant steel.
It was acquired at about the same time as a cable plough for the Discoverer which will bury the cable as it comes off the reel at a depth of 3m under the seabed. The Sea Stallion 4 cable plough has been especially adapted by IHC Engineering Business, to take the large diameter 132kV cable. Together, the cable reel and plough cost some £5m.
This is not the end of the story for the Aberdeen based subsea construction company, as Mike Daniels added that there is a new 7,000 ton reel currently being built for them, again by Parkburn. Positioning it on the 92m barge is not just a question of putting it down. The weight of the cable carousel, especially when loaded with a full reel, was sufficient to require a marine architect on board to work out the positioning.
The ongoing drive for size, Daniels explains, is being pushed not just by larger projects but also by the ever increasing distance of the wind turbines from shore, which is requiring ever longer runs for the power transmissions cables.
