December 14 - Boskalis has completed a complex operation to float-over and install a 22,000-tonne topside onto a 41,700-tonne spar hull.
Boskalis claims that the project, which culminated at the Aasta Hansteen field approximately 300 km off the coast of Norway, broke engineering records with the transport of the largest and heaviest spar hull ever.
Through its subsidiary, Dockwise, Boskalis used two S-class vessels to transfer Statoil's Aasta Hansteen topside from its carrier vessel, White Marlin, and position it on the hull.
The S-class vessels were positioned either side of White Marlin, which ballasted down, lowering the topside onto the decks of the two smaller vessels, before moving into position above the spar hull for the mating procedure.
The operation signals the end of a significant project that also saw Dockwise ship the 41,700-tonne spar hull from South Korea to Stavanger. The cylindrical buoy had a diameter of 50 m, a length of 198 m, and was transported to Norway using Dockwise Vanguard.
This was followed by White Marlin's delivery of the topside, also from South Korea.
The Aasta Hansteen oil and gas production and storage platform is set to commence operations in early 2018.
See a time-lapse of the float-over installation here.
