Having built over 20 years’ experience in the Oil & Gas industry, Seaway Heavy Lifting turned its extensive expertise to renewables – particularly wind energy. The offshore contractor has already gained a reputation for excellence and an impressive track record. We take a look at its project highlights.
SylWin alpha Platform
Transportation and installation of the SylWin alpha Platform. Under the direction of Seaway Heavy Lifting, one of the world’s largest convertor platforms was installed to the west of Sylt, the East Frisian Island.
The platform was so large and heavy that the ingenious ‘float-over method’ was used to lift it from a pontoon on to the already installed jacket. This approach had been used successfully in the Gulf of Mexico and in the Far East, but this was the first time that a platform this size was installed using the method in the North Sea.
Siemens commissioned Seaway Heavy Lifting to perform the unusual operation, and in turn called in the assistance of two other Dutch maritime service providers. The 14,000Mt SylWin alpha Platform topside was transported on a pontoon that had been positioned in between the jacket legs.
The platform topside was installed on to the legs of the jacket by ballasting the pontoon and a subcontractor was responsible for this phase. Afterwards, strand-jacks were used to lift the platform to its final height above the sea.
The 83-metre long, 56-metre wide and 26-metre high SylWin alpha Platform is the largest of its type. Earlier this year, Seaway Heavy Lifting used its crane vessel ‘Oleg Strashnov’ to install the 5,800Mt jacket. The ‘Oleg Strashnov’ is one of the world’s ‘strongest’ crane vessels but it is not strong enough to lift the SylWin alpha jacket. Therefore, the decision was taken to add additional buoyancy in the form of buoyancy tanks and to submerge the pontoon on site. This complicated operation has been preceded by more than a year of preparatory work.