The Liebherr LTR 11200 crawler crane was developed pri-marily for operations involving wind farms, and it has since proved its value in that sector many times over. The most powerful telescopic crane in the world has now also mas-tered its first commitments on the high seas – and has shown itself to be a champion.
Danish shipowner DBB Jack-Up Services A/S made ar-rangements with Liebherr in the early part of this year for the crane superstructure of an LTR 11200 to be mounted on its self-propelled jack-up barge WIND. The connection between the slewing ring and the barge is provided by means of a strong, stable tube element, which is integrated into the structure of the ship. The WIND is the first ship to have a permanently-mounted telescopic crane on board.
DBB have been operating Liebherr mobile cranes on land for service at wind power installations for a number of years. Thanks to the excellent experiences gained with the products and the partnership support provided by Liebherr, DBB turned to the crane manufacturers from Ehingen when it came to creating a solution together for the installation of a powerful telescopic crane on a barge.
The main reasons for DBB Jack-up Services A/S taking ad-vantage of a telescopic crane were the much smaller space requirements in comparison with the lattice boom cranes which would normally be used, and the lower centre of grav-ity of the crane thanks to the fact that the boom can be com-pletely retracted. These advantages make it possible for a substantial hook height to be achieved with the on-board crane even with a relatively small barge. DBB also point to the advantage of their chosen concept in that the LTR 11200 is a standard product with a reputation for reliability, which means that Liebherr can ensure high availability and rapid supply of any spare parts that might be needed.
The LTR 11200 has been given a number of technical modi-fications for operation on the high seas. Instead of the Diesel engine, an electric motor will be used for operating the crane, powered by the high-performance power plant of the ship. This means there is no further need for environmentally harmful and flammable fuel to be kept on the deck. The crane is powered by bio-hydraulic oil for reasons of environmental protection, and when it came to the painting and the design of the electrical switch cabinets particular account was taken of the special conditions encountered at sea.
It took just one week for the crane to be installed on the barge in May 2010 at the Orskov shipyard in Frederikshavn, and by June the WIND was already at work at the Dutch OWEZ offshore wind farm. Since then the concept of the telescopic crane on the jack-up barge has proved to be out-standingly successful. The development of wind power, in particular in the offshore sector, is set to increase still further, and DBB, with the WIND and the LTR 11200, are extremely well equipped to secure a share of this growing market.
DBB Jack-Up Services A/S was established on 1 January 2008 as a subsidiary of the company Dansk Bjergning og Bugsering A/S (DBB – Danish Salvage and Towing Com-pany Ltd.), and has its headquarters in the Danish city of Aarhus. The company, with the most modern equipment available, offers first-class service to the wind power industry, with the focus on the maintenance of the installations.
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Offshore WIND staff, December 13, 2011; Image: Liebherr