Allseas is preparing load tests for the Pioneering Spirit’s revolutionary jacket lift system. This marks the final weeks of the installation phase. Before this, 11,000 tonnes of high-density ballast has been mixed and pumped into the two main beams and two steel ballast frames, a 24-hour operation that took a week to complete.
The ballast is required to help upend the massive 170-metre beams. Watch a short fly-over of the jacket lift system beams in the video below.
In addition, 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 twenty four-kilometre 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.
Now preparations are ongoing to upend the beams, a challenging operation requiring the upend system, derrick hoist and water ballast systems to work simultaneously for the first time. Allseas has made a documentary consisting of multiple episodes on building the jacket lift system. The first two are available in the link below.
Jacket lift system
The jacket lift system is being built to install and remove entire jackets up to 20,000 tonnes, also in a single lift. It can operate in hostile weather conditions and the new technology offers a safer and faster alternative to conventional systems and removes the need for a barge.
While the technology is ground-breaking, the way the system works is rather simple, states Allseas. After making cuts to a jacket’s foundation piles at seabed level, hoisting blocks suspended from the lifting beams raise the jacket at the main legs. The jacket is subsequently aligned with the beams, reclined, and skidded further inboard before transit.
In September, the largest part of the jacket lift system were installed on board: the 13-metre wide main beams. The system is now in the final installation phase. The complete jacket lift system is to be ready for the first projects in summer 2022.
Allseas‘ Pioneering Spirit is the largest vessel in the world and capable of lifting and transporting entire platform topsides of up to 48,000 tonnes in one piece using motion-compensated single-lift technology. The twin-hulled vessel is 382 metres long and 124 metres wide.
The picture at the top is a still from the video above (by Allseas).