Allseas has started the testing and commissioning phase for the Pioneering Spirit’s new jacket lift system (JLS) capable of lifting and transporting the largest supporting structures. 

In-harbour trials include raising and lowering the 170-metre lifting beams individually and, when connected, simultaneously. This enables Allseas‘ engineers to calibrate load measurements and verify the control modes and safety systems.

Current tests focus on the starboard beam, increasing the upend angle in phases to 110 degrees, the angle the beams reach during commercial jacket lifts. Up to 60 degrees, the upend system does most of the work. From 60 degrees, the centre of gravity moves outside the vessel, and the derrick wires control the tilting.

During operations, the aft-mounted beams lift and support entire jackets weighing up to 20,000 tonnes. This innovative technology enables direct transfer of structures to and from the quayside and eliminates the need for support barges. Significantly shorter operating times translates to major emissions savings.

At the turn of the year, Allseas mixed and pumped 11,000 tonnes of high-density ballast into the two main beams and two steel ballast frames. The ballast is required to help upend the massive 170-metre beams.

A total of 100 km of electrical cables have been thread through the beams and upend system, connecting the many different drives, winches, pumps and push pull skids to power-up and control the entire system. A further 20, 4-km steel wire ropes have been reeved through the main hoist blocks and derrick hoist. Fixed and adjustable grillages, which will distribute force along the beams during jacket lift operations, were fitted in parallel.