Much publicity has accompanied the story of Allseas’ giant decommissioning and pipelaying vessel Pioneering Spirit. After a test lift and first commercial removal of Repsol’s Yme platform in the Norwegian North Sea it has more than passed its first real test with removal of Shell’s 24,200t Brent Delta platform topsides. Now details about its part in the record-breaking lift of this decommissioned oil platform topside have been revealed by Kotug International BV.
Five years of engineering and study work preceded the operation yet it took a mere ten seconds for Pioneering Spirit to lift the topside clear of its jacket. Preparations included strengthening the topside’s under-deck and the cutting of the connection between the two.
The process involved Pioneering Spirit positioning itself beneath the topside and using a combination of ballasting and active motion-compensated lifting beams raising the topside. After sailing to Hartlepool UK it was lowered onto Allseas’ 200m long, 57m wide barge Iron Lady for towing ashore.
Operations of this scale require a cast of supporting vessels and it is here where Kotug was involved deploying two ASD tugs and two Rotortugs to handle Iron Lady including positioning within the slot between Pioneering Spirit’s hulls and removal once loaded. The four tugs then towed Iron Lady into the river Tees, the eventual destination being Able UK’s decommissioning yard.
Watch a fascinating short video of Pioneering Spirit removing the Brent Delta topsides.
Kotug tow master Bas van Hoorn commented: “We have worked for Allseas in previous offshore projects and we were honoured to be selected for this ground-breaking project as well. The towage operations were carefully prepared in close cooperation with Allseas with extensive calculations and risk assessments to determine the safest and most efficient towage plan for the Iron Lady. Thanks to great collaboration with the tug crew, Tees pilots, Allseas team and Shell, we can look back on a job well done!”