A new generation of lightweight cranes
Design & Proposal Engineer
Damen Shipyards Group
Huisman Equipment BV
The Damen Shipyards Group, together with Huisman, the global specialist in lifting, drilling and subsea solutions, and jack-up vessel specialist GustoMSC, has developed an economical and effective solution for wind farm operators looking to maintain the next generation of supersized wind turbines. Generating up to 15MW each, these new turbines will have components weighing far more than their smaller equivalents, mounted 130 metres or more above sea level. Currently lifting such weights to these heights can only be achieved using large, heavy cranes with long booms mounted on the largest premium platforms, and these are expensive to both build and operate.
Working with GustoMSC, Damen recently introduced the DG Jack range of jack-up vessels. Ranging in length from 36 to 88 metres they are ideal for operations and maintenance (O&M) work on the current generation of offshore wind turbines. However Damen was already looking at the next challenge ahead, that of how these compact units would be able to service the new turbines currently under development by the likes of Siemens, AMSC and MHI Vestas.
Damen invited long-standing partner Huisman to contribute its extensive experience in designing and manufacturing lightweight offshore cranes to assess the feasibility of devising a compact solution that would enable the existing DG Jack vessels to handle the heavier turbine components without adding to their weight. After much development work, Huisman proposed its foldable crane design that does away with the need for a single, long boom and spreads the enormous loads generated across the entire DG Jack platform.
The Foldable Offshore Crane uses a folding boom that bypasses the problem of the high loads that go with raising a long, heavy boom. This solution delivers the required low weight and long reach, together with the ability to handle great heights. The fact that the top section folds beneath the mid-section when at rest enables it to fit on a shorter deck, and the simple geometry of the structure gives it a much lower construction weight when compared to a single boom or telescopic boom solution.
“We have four versions currently on offer,” says Timon Ligterink, Sales Manager at Huisman. “These range in size from one offering a 100 metre hook height above deck and a maximum load of 90 tonnes to another delivering a 160 metre hook height and a maximum load of 600 tonnes. This means that the larger versions will be more than capable of providing O&M services to the super-sized wind turbines expected in the near future.” “Approaching Huisman to find a reliable solution for heavy lift at great heights was the logical approach,” adds Staffan Utzon at at Damen’s Offshore & Transport department, “and the outcome is quite in line with our expectations. The team at Huisman have proven their strength in their ability to find innovative solutions for the challenges that they encounter. The light weight of the crane has given us the opportunity to create a more compact platform that delivers the same high capability at a lower overall cost.”
For Damen and its clients, this collaborative process has delivered a solution that will be ready to meet the needs of the offshore wind sector as its technology evolves, and which will contribute to bringing down the overall costs of wind energy, making it ever more competitive against less sustainable alternatives.