Allseas Plans Even Bigger Heavy Lift Ship
Offshore services company Allseas is planning to build a heavy lift ship bigger than its existing vessel Pioneering Spirit, reports Reuters news agency.
The $3 billion vessel, Amazing Grace, is expected to be able to remove the world’s largest oil and gas platforms in a single lift when they are decommissioned, Allseas CEO Edward Heerema said.
Pioneering Spirit is the largest construction vessel ever built. Inspired by the offshore heavy lifting pioneer Pieter Schelte Heerema (1908–81) and designed completely in-house, the vessel is designed for the single-lift installation and removal of large oil and gas platforms and the installation of record-weight pipelines.
Built at the DSME shipyard in South Korea (2011–14), the vessel commenced offshore operations in 2016 with removal of the 13,500 ton Yme production unit in the Norwegian North Sea. The single lift of Shell’s 24,200 ton Brent Delta platform topsides in April 2017 marked the word’s heaviest offshore lift.
The twin-hulled vessel is 382 meters (1,253 feet) long and 124 meters (407 feet) wide. At the bow is a slot, 122 meters (400 feet) long and 59 meters (194 feet) wide, that enables Pioneering Spirit to straddle a platform and remove entire topsides – up to 48,000 tons – in a single lift using eight sets of horizontal lifting beams. Two tilting lift beams for the installation and removal of jackets – up to 20,000 tons – are located at the vessel’s stern. Complementing the lifting systems is a 5,000 ton special purpose crane for additional lifts such as lighter topsides and jackets, modules and bridges.
Pioneering Spirit’s large ship size gives her very good wave response behavior, superior to semi-submersible crane vessels in operational wave conditions; topsides and jackets can be installed or removed in significant wave heights of up to 3.5 meters (11.5 feet). While the vessel moves due to wave action, all motions relative to the platform are eliminated by engaging the active motion compensation system, which enables Pioneering Spirit to make large lifts in hostile seas.
Pioneering Spirit can sail under her own power at a high transit speed, making her suitable for worldwide use. Operating on full dynamic positioning, she can work accurately in any water depth, while her light ice class will extend the periods in which she can operate in polar regions.
She is also equipped with pipelay equipment that makes it possible to install record-weight pipelines from shallow to ultra-deep water, and achieve high lay rates. With an S-lay tension capacity of 2,000 tons, she surpasses Solitaire as the world's largest pipelay vessel. Pioneering Spirit commenced pipelay for the first line of the dual 32-inch, 900-kilometer (560 mile) TurkStream pipeline in the Black Sea in June 2017.
When Pioneering Spirit is required for platform topsides installation or removal work, the stinger is removed from the bow section of the vessel and stored on a purpose-built stinger barge, Bumblebee.
For the transfer of jackets and topsides to/from Pioneering Spirit, a 200-meter (656-foot) long, 57-meter (187-foot) wide cargo barge has been purpose built. This barge, Iron Lady, with its relatively shallow draft, enables the loading or offloading of structures to or from the yard in case the water depth at the quayside is insufficient for Pioneering Spirit.