Terex CC6800 used on Hooksiel wind farm repairs

Wind farm operator, Bard, contracted Maxikraft to lower and re-fit the hub/rotor assembly and nacelle of a 90m-tall wind turbine while the crane was mounted on a heavy lift pontoon.

To perform the lifts the crane was rigged with a 90m main boom and 18m fly jib, in LFVL configuration.

250t of counterweight was required in addition to 80t of central ballast on the carrier, and 240t of superlift ballast was also used to allow the CC 6800 to achieve a working reach of 22m.

The operation required four carefully planned lifts, with the 280t nacelle being the heaviest load lifted by the 1,250t Terex crane.

But before the nacelle could be removed for repairs, the 170t, 127m-diameter rotor hub assembly had to be lowered.

Explaining the difficulty involved in the lift, Maxikraft’s crane operator on the job, Raik Hanisch, said, “An offshore lifting operation is obviously much trickier than a land-based assignment, since the wind and sea can act up at any moment and cause a great deal of instability.”

Once repairs were completed, the hub/rotor assembly and the nacelle were replaced to complete the work to schedule.

Project manager Steffan Lehmann commented: “The way the project moved along smoothly showed that the Terex CC6800,, with its capacity and its enormous flexibility in the way it can be configured, should be the first choice of anyone who is planning to lift this type of large weight — also when working under difficult operating conditions.”