Sail away of latest made-in-Lowestoft offshore structure
– 12th May 2016
The jacket foundation for the Dudgeon offshore windfarm substation departed from Sembmarine SLP on 11 May 2016. The 1,500 tonne structure was manoeuvred out of the harbour at Lowestoft on a barge, towed by three tugs.
The seagoing tug Pegasus met the barge just north of Lowestoft at West Holme buoy where it was handed over by Sembmarine SLP to installation contractor Seaway Heavy Lifting. Lead tug was Multi-Tug 27 with Avant 20 behind, braking and steering. They were assisted by Eastern Marine Services’ vessels Defender and Surveyor, as guide and transfer vessels.
Pegasus then towed the jacket 100km to the Dudgeon site 32km off Cromer, Norfolk, to await the arrival of installation crane vessel, Seaway Heavy Lifting’s Stanislav Yudin, from Holland. The jacket will be lifted into place by the anchored Yudin’s crane and sunk into the seabed using suction bucket technology, the first time it has been used on an offshore substation in UK waters. On board Yudin to supervise its installation will be Sembmarine SLP’s offshore manager Brett Hurrell with staff from suction bucket specialists SPT Offshore.
Sembmarine SLP was contracted to work with Siemens Transmission and Distribution Ltd (STDL) to design and build the offshore substation for windfarm’s owners Statoil, Statkraft and Masdar. The offshore substation will house all systems needed for the handling and export of power from the 402MW windfarm to the onshore substation at Necton, Norfolk and connects to Dudgeon’s 67 turbines by 12 inter-array cables. Two export cables will take the power to Necton.
The wind farm will generate enough electricity to power 410,000 homes.
Matthew Wooltorton, Sembmarine SLP’s project manager for the offshore substation, said: “There is a total of 6000 tonnes moving away. It is not a quick operation, at a speed of about 4 knots, possibly up to 10 knots once at sea.”
The team had been planning the sail away for months to meet the strict criteria and ensure a safe and smooth departure, he said. Yesterday was chosen for the perfect weather conditions.
“We are already planning the next sail away in August for the topside and are booking tugs. It is satisfying to know it is now complete and went out on time and everything has gone smoothly watched by our workforce on the module.
“It has been a prominent feature of the Lowestoft skyline for so long.”
The jacket is designed to stand in the sea for at least 25 years.
Latest Case studies
In September 2015 Sembmarine SLP was awarded the contract to carry out the construction of the Power Generation Module (PGM) and Bridge Links for the Maersk Oil Culzean project development in the North Sea.
The offshore facility has been designed, engineered, procured and constructed in Sembmarine SLP’s Lowestoft yard and includes suction bucket technology, a first for an offshore substation in UK waters. Part of Statoil’s £1.5 billion Dudgeon Offshore Wind Farm project to power more than 410,000 UK homes, the structures have been designed to meet exacting specifications.