Within the C-Power wind farm there are 2 types of foundations. There are 6 turbines with a GBF foundation (Gravity Based Foundation) (Phase 1) and 48 turbines and theOTS with a Jacket foundation (Phase 2 & 3). Each turbine has 2 boat landings (on the foundation) and a heli winch-down platform which are used for access.

Gravity Based Foundations

The Gravity Based Foundation is a concrete conical / cylindrical structure of some 45m in height. This massive structure was built onshore, at the “Halve Maan” site in Ostend, and transported semi-submerged to the offshore site, where it was put on the seabed. An “empty” GBF weighs some 3000 tons. Once installed on the seabed, it was filled with sand; its total mass is 6000 tons.



GBF height38,5 m to 45 m
GBF weight 2800 tonnes to 3000 tonnes
Material +/- 1060 m3 concrete + 255 tonnes reinforcement
Diameter base slab 23,5 m
Thickness concrete wall0,5 m

Jacket foundations

The jacket foundation is a steel quatropod structure grouted to and supported by 4 pin piles. The pin piles (+-2 m in diameter) are up to 50 m long and driven into the seabed. A transition piece is welded on top of the jacket, providing an access platform with 2 cranes and a cylindrical “barrel” to support the tower of the turbines.



Jacket height37,7 m - 47,8 m
Jacket weight+/- 500 tonnes
Jacket OTS weight 800 tonnes
Jacket Material Steel