A stalwart vessel of the Sheringham Shoal Offshore Wind Farm fleet has left the Greater Wash after reaching another project milestone, the completion of the undersea works to prepare the site for the installation of the cables that transport the power generated by the wind turbines.
The 77m vessel Smit Constructor has been home and workplace to around 60 riggers, divers and other workers from contractor Visser & Smit for several months as they have undertaken work to ensure each foundation was ready for the arrival of the cable laying vessel.
Offshore wind farms are known by the white wind turbines standing high above the waves, but of equal importance is what people do not see – the subsea components including foundations, cables and associated equipment hidden below the water but vital to every project.
At the 317MW Scira Offshore Energy project, the foundations are all in place and now preparations are complete for the installation of the remaining infield cables that will transmit the power from the turbines to the offshore substations.
Working alongside the divers on the seabed were state-of-the-art remotely-operated vehicles (ROVs) equipped with cameras, lighting and special tools such as grabbing arms to carry out the necessary tasks.
The teams on Smit Constructor worked on rotation around the clock, installing the funnel-shaped bellmouths along with lengths of plastic pipe through which the infield cables will eventually be fed.
They also lowered net bags full of rocks and weighing several tonnes, aptly known as “rock bags”, into position to help stabilise the bellmouths and plastic pipes and prevent seabed scour by tidal currents and wave action.
Sheringham Shoal Offshore Wind Farm now has 31 of its 88 turbines in place and is scheduled for completion in late summer 2012.
The project is owned equally by Statoil and Statkraft through joint venture company Scira Offshore Energy Limited. Statoil is the project manager during construction, while Scira will be responsible for the long-term operations and maintenance.
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Offshore WIND Staff, March 13, 2012; Image: smit