The crane, owned by Bilfinger? Mars Offshore, stands 120m high on the Ostrów Brdowski island and is a permanent fixture at the facility in the northwest of the country. It is close to the German border, from where Schmidbauer GmbH & Co. KG accepted a scope of work to rig the crane, utilising two of its four 350t hooks.
The centrepiece of the below-the-hook solution was a Modulift spreader beam, type MOD 400/600, which was assembled with an 8m span. It was part of a custom 600t rig, including the hook block, that was attached to the crane to lift 91 transition pieces.
Philipp Verges, sales manager global projects and key account manager offshore at Schmidbauer, said: "We assembled a custom rig based on the successful application of a similar below-the-hook solution for another project. Bilfinger retained control of the lifting operation, but anything related to the rigging equipment was our responsibility so we combined our expertise with the best and most suitable equipment available."
Verges explained that on each of the two hook blocks there were two 158t, 1.6m slings attached to the 300t shackles of the MOD 400/600 spreader. From the 400t shackles, four 297t, 12m wire rope slings were connected to four 125t wide body shackles that held the 600t hook block.
The beam, sourced from Schmidbauer stock, was used as an inverted spreader, Verges said, owing to the two pick points above it and the need to bring the slings together in one point. More commonly, when one hook block is used, the bigger shackles are on top, while the smaller ones and the drop link face down.
Verges added: "The transition pieces were tailed from horizontal into a vertical position. After placing electrical components and secondary steel, they were lifted onto barges, which transported about six pieces at a time. The project started last month [May 2016] but remains ongoing."
Bilfinger? Mars Offshore is a joint venture between Bilfinger,? an international engineering and services group and a major provider of offshore wind power solutions; and MARS, a Polish closed-end? investment fund, managing a portfolio of companies in the shipyards and the offshore? steel structure industry.