Weldex mission complete

In July 2007 Weldex Offhore Ltd, based in the UK, was tasked with completing the onshore erection of the second wind turbine for the Beatrice Demonstrator project, sited off the north eastern coast of Scotland.

“We had already erected the turbine ready for loadout last year, but as it didn't sail we took down the rotor and split the three blades from the hub for storage over winter,” This left the TIF (turbine interface frame) support, the 230 tonne tower and 315 tonne nacelle erected. In addition, last year we installed the 150 tonne tandem spreader bar to the tower,” said Brian Hyde, Weldex technical services manager.

The Rambiz heavy lift crane vessel, operated by Belgium-based marine contractor Scaldis, came in and took a Weldex Kobelco SL6000 crawler crane, with 48 m short boom, away, along with the turbine.

Hyde explained that the SL6000 was used to install the boat landings and removed the temporary supports for the JIF (jacket interface frame). The Rambiz then lifted off the 250 tonne JIF in two halves. These structures were returned to land for offloading and storage by dumb barge.

“The large tandem lift beam has a hydraulic gate that opens to release the beam from the tower. The two crane hooks are obviously above the beam but not above the structure height. Stability is achieved by attaching large pendant slings down to the TIF area, so in effect tit is lifted from the bottom and the lift beam slides up the tower to stabilise it,” Hyde added.