UK-designed innovations supporting foundation installation phase
Inch Cape comprises bespoke, hand-crafted components including major innovations that have made the news such as being the first UK project to use Vestas V236 15 MW turbines and the first with a Siemens Energy double Offshore Transformer Module (OTM®).
It is also full of less visible initiatives which have collectively both progressed Inch Cape’s development and construction and will also contribute knowledge and benefits to future offshore wind projects.
One UK company – creative engineering firm TWD – has been the source of a number of these behind-the-scenes innovations supporting the foundation installation phase of the project. Here is a run-down of their involvement:
Temporary navigation structures
Once installed, monopile foundations need navigational lights to ensure they are visible to other marine users. TWD was tasked with designing a temporary navigation structure (TNS) to support the navigational lights that was lighter, easier to transport and more cost effective than previous designs.
With this brief, the design engineers managed to reduce the steel weight of the units to around 250 kilograms each while ensuring they could be transported by road. They are designed to stack so are easy to store and take up minimal vessel deck space and can be easily handled by a crane for simple mounting during installation and removal.
This design sets a new standard for offshore wind farms using monopile foundations, and once finished in use on Inch Cape, will be available for other developers or marine contractors to purchase for their own use in a sales process that is now underway.
Pile installation frame (PIF)
The idea of using a frame for foundation installation for offshore wind farm is not unique however the hydraulics and technology on the Inch Cape PIF (also known as the pre-piling template) is innovative and will significantly support and de-risk the installation of the 18 three-legged jackets. Each jacket has three pin piles which need to be installed first with stringent accuracy, stability and efficiency.
Given this brief, TWD engineered a 1,000-tonne structure to install pin piles at 32‑metre centre‑to‑centre spacing with a linear placement tolerance of just ±20 millimetres, making allowance for offshore challenges such as waves, currents, and varying seabed conditions.
The template is equipped with a hydraulic levelling system which can compensate for seabed gradients of up to three degrees. Maintaining the template in a horizontal position ensures the piles remain within strict tolerances during pitching, lowering, and driving which is essential to guarantee that the jacket foundations are installed safely and accurately.
The template was designed with hydraulically actuated retractable upper and lower shims. The hammer and follower enter the sleeve while the lower shims remain engaged, ensuring secure alignment of the pile throughout its installation. A dedicated lower-shim retraction mechanism will prevent jamming during lift‑off, reducing operational risk and improving the efficiency of repeated installations.
A multidisciplinary effort and analytical approach from TWD’s structural, marine, and geotechnical engineering teams was required to ensure that the final design met the Inch Cape’s demanding performance requirements at the Lykomitros Steel-fabricated frame was practical for offshore handling and installation.
The PIF can potentially be used by future projects, reducing costs and the manufacturing carbon footprint and is now available for sale to interested developers or contractors.
Jacket foundation covers
Through collaboration with aluminium cover supplier Aluwind, TWD helped deliver bespoke covers to protect internal electrical equipment on Inch Cape’s jacket foundations. The stock covers required extensive modification including a state-of-the-art auto-locking and alignment system so the cover could clamp to the jacket flange and release automatically when lifted by the crane. This also required custom-designed lifting tool to interface with the jacket cover.
The cover locking pins and integrated bumpers mate to the lifting tool via a rotationally locked interface which allows precise control over the orientation of the cover. The internal guides designed by TWD constrain the rotation of the cover and prevent clashes with jacket furniture.
An electrically operated locking pin with three layers of control to prevent jamming was included in the lifting tool to ensure the cover is not lost during use. The covers need to be lifted at a height of at least 80 metres, with no line of sight, so a remote camera system was also incorporated in the lifting tool.
Finally TWD also provided engineering, procurement and construction management (EPCM) services, overseeing the interfaces between suppliers, manufacturers and vessel owners during the busiest periods for Inch Cape installation contractors and foundation teams.
Some other major innovations on the project include:
| Vestas V-236 15 megawatt (MW) turbines | This turbine is the largest to date to be installed in the UK. |
| Fifteen year turbine warranty service agreement (WSMA) with Vestas | By agreeing a long-term contract this will support sustainable jobs in local areas. |
| Siemens Energy Offshore Transformer Module® (OTM®) | This award-winning design is lighter and has a reduced seabed and material footprint. It also features the world’s largest offshore transformers. |
| Ningbo (Orient Cable) 2000mm-square AC cable | The two 85 kilometre cables (fabricated in three 28 kilometre lengths each) is the largest ever |
To find our more about Inch Cape’s innovations for sale you can visit the Dixon Marine Consulting Inch Cape page here.
