Hornsea Met Mast

Keystone‘s patented twisted jacket or Inward Battered Guide Structure (IBGS), a finalist in the Carbon Trust’s Offshore Wind Accelerator competition, was designed to support the Hornsea met mast installed in the North Sea.



North Sea

Nameplate Capacity

Keystone was one of four finalists in the UK Carbon Trust’s Offshore Wind Accelerator global foundation design competition to reduce the CAPEX of offshore wind turbine foundations. Keystone’s patented IBGS (Inward Battered Guide Structure), known as the “Twisted Jacket” in the offshore wind industry, proved to be 20% less expensive than traditional designs. Keystone’s jacket was the first of the winning concepts to be demonstrated. A Twisted Jacket prototype was built in Europe and become of the first structure installed Scottish territorial UK Round 3 waters.

Keystone’s scope of work included conceptual and detailed design of the substructure and foundation, which included structural engineering, electrical engineering, and drafting services for Keystone’s patented “Twisted Jacket”. Additionally, the scope included evaluation of European fabrication yards, design of fabrication cradle, fabrication support, design of guide structure transportation support and hydraulic tie-downs, development of installation Method Statement and Choreography, on-site construction support, and project management services.

The patented twisted jacket was installed in the Gulf of Mexico for ExxonMobil in 2005 and survived Hurricane Katrina with no damage despite the proximity to the eye of the hurricane.