A jack-up vessel is working close to shore off a Norfolk, UK beach collecting seabed data to shape the design of two major wind farms.

'Haven Seariser 2'

'Haven Seariser 2' on the nearshore at Happisburgh, Norfolk. Photo: Vattenfall

Red7 Marine’s 500t Haven Seariser 2 is on the nearshore off Happisburgh while its geotechnical engineering team take samples for Swedish energy group Vattenfall’s Norfolk Vanguard and Norfolk Boreas developments.

The 1.8 GW Norfolk Vanguard was granted consent on 1 July, while Norfolk Boreas is in the examination phase. The projects will produce 3.6GW of energy altogether.

Andy Galbraith, Vattenfall’s head of geoscience, said: “The information gathered during these site investigation surveys will be used to fine tune the design of the export cable and associated installation techniques.

“Horizontal directional drilling will be considered for installing the cable underneath the beach and the area of the shore which is submerged at high tide and exposed at low tide. These surveys will help determine the best technique to use.”

29m barge

The Haven Seariser 2 is a 29m long barge fitted with long support legs jacked down onto the seafloor. It is gathering borehole samples, down to a maximum of 30m.

The process will build an understanding of seabed sediment layering to decide the installation methodology for the wind farms’ main transmission cables at their landfall at Happisburgh.

Several larger vessels are working further offshore carrying out similar sampling in a four-month campaign by Fugro.

Onshore construction of Vattenfall’s Norfolk Projects is due to start in 2022-23. Offshore works are due to start in the mid to late 2020s.

By Rebecca Jeffrey