Wind it on

Building Burbo

Mammoet Van Oord, founded in 2002 to carry out offshore wind farm installations, was contracted to work on the Burbo Banks Offshore Windfarm off the coast of Liverpool, UK. The contract required Mammoet Van Oord to use its Jumping Jack lifting barge to install 61 foundations for the turbines.

The Jumping Jack is fitted with a Manitowoc Model 1200 ringer crane with a lifting capacity of up to 1,300 tonnes and can be rigged with different boom and jib lengths. There is also space on deck for an additional 2,000 tonne crane to be fitted if required.

Work on the Burbo Bank wind farm started in early 2006 with the installations of foundations for the turbines. The wind farm will contain 25 Siemens turbines with a capacity of 3.6 MW. Each will have three 52 m long blades on 87 m high towers.

Each foundation consists out of a monopile and a transition piece. The monopile has a length of approx. 35 m, an outside diameter of 4.70 m and weighs 220 tonnes. The transition piece forms the connection between the monopile and the turbine tower and weighs 230 tonnes.

The monopiles and transition pieces were transported by Mammoet Van Oord from Hoboken to site by coasters before being offloaded directly on to the Jumping Jack.

Once three sets of foundations were on board, the monopile was upended and placed into the pilegripper and driven by a hydro hammer between 20 and 25 m into the seabed.•