Allseas installing 20,000t Jacket Lift System on Pioneering Spirit
How do you lift complete offshore steel jackets – equal in weight to 2 Eiffel Towers – off the seafloor? Conventionally, these structures need to be cut into small sections suitable for lighter crane lifts. However, our vessel Pioneering Spirit will be able to remove and install jackets weighing up to 20,000t in a single lift.
How does it work? Put simply, jackets are lifted over the stern of the vessel. After foundation piles are cut near the seabed, hoisting blocks are lowered from two towering main beams and connected to hooks on the top of the jacket. The jacket is then pulled out of the water, aligned with the beams and tilted horizontally. For installations, the operation is reversed.
After 18 months of production at sites around the globe, this unique lift system is beginning to take shape on board Pioneering Spirit. Assembly is in full flow, with many of the 200-plus subcontractors finalising their scopes and key components arriving daily, including the “Upend System” that raises the two 170 m long main beams into the jacket lift position.