The jacket foundations consist of a steel jacket with four legs and can be divided in several parts, which are being produced in different manufacturing yards throughout Europe. The final jacket assembly takes place in Hoboken (Belgium) at the yard of Smulders Foundations.
- The midsection: this is the transition piece between the main jacket part and the wind turbine tower section
- The main jacket part
- The pile stoppers: these form the transition between the main jacket and the pinpiles, four per jacket
- The secondary steel elements (such as anodes, boat landings, ladders ...)
The main jacket part is made by Smulders (Hoboken, Belgium) in several stages.
Jacket tubulars are supplied by subcontractor EEW, both in EEW Germany and EEW Korea.
The pile stoppers allow a grouted connection between each of the four legs of the main jacket part and the respective four pinpiles underneath. The pile stoppers are produced by Famaba (Poland) and Iemants (Arendonk, Belgium).
The midsection is completely assembled, blasted and painted by Smulders' subcontractor Willems (Balen, Belgium). This midsection, also called transition piece, forms the connection between the main jacket part and the windturbine. Each midsection contains 4 castings (transition between the ring stiffner and the 4 braces towards the midsection deck). These castings are being produced by Metalodlew (Krakow, Poland), partly by Allard (Turnhout, Belgium).
The secondary steel items are made at several subcontractors such as Rheden (Netherlands) and Spomasz (Poland) for the j-tubes, bell mouths, ladders, boat landings handrails and platforms.
The pile stoppers, midsection and secondary steel items are delivered to Smulders for assembly to the main jacket part.
In addition to above parts there are the pinpiles which are made at SIF (Roermond, Netherlands) and are not part of the assebly in Hoboken. The pinpiles are driven from a jack-up platform equipped with a special built installation frame, dimensions of the piling template are 18 m x 18 m (= footprint of the jacket), this template is being recovered after pile driving, to re-use it for the next location. This pile driving is done before installation of the jacket.