One of the world’s largest and most powerful heavy lifting floating crane ships has arrived off the Cork coast to begin the final decommissioning stage of two famous gas platforms.
Dramatic aerial footage shows the Thialf, a 14,200 metric ton floating behemoth with two giant cranes, positioned in the Kinsale area gas field, some 30-miles off the south coast.
It will spend the coming weeks dismantling the superstructures and equipment associated with the field’s Alpha and Bravo platforms.
The footage shows the Thialf, which is technically classed as a semi-submersible crane vessel (SSCV), dwarfing the Bravo rig.
The Thialf was famous for being the largest crane vessel in the world until it lost the title to an even bigger SSCV, the Sleipnir, in 2019.
Its statistics are staggering.
In 2000, the Thialf set a world record by lifting the 11,883 metric ton Shearwater rig topside in the North Sea. The record lasted 14-years.
At 210m long, the Thialf is almost one and a half times the length of Croke Park, and at 88m wide, it’s almost the same width. Its work deck stands at almost 50m high.
Built in 1985 by Mitsui Engineering and Shipbuilding under the name of DB-102, it was owned by McDermott International until 1997, when it was taken over by Heerema Marine Contractors and renamed Thialf.
Its two massive cranes, whose arms when fully extended can soar up to 540ft in the air, have a combined maximum lifting capacity of 14,200 tons - roughly the equivalent of 28 jumbo jets.
The ship uses a hi-tech dynamic positioning system to pump vast quantities of water into its tanks to act as ballast, and to maintain its position while lifting and to provide a solid work platform.
Over the years, it has been used in several high-profile construction jobs such as installing the Erasmus Bridge in 1995 and the topsides on BP’s rig, Holstein, the heaviest single piece foundation piles for Chevron’s Benguela Belize compliant tower, a gravity-based drilling platform which is the fifth tallest freestanding structure in the world.
It was also involved in decommissioning the controversial Brent Spar oil storage buoy in 1998.
Its owners describe it as their workhorse for “its ability to get the work done, regardless of the job, location, or weather”.
Work on the decommissioning of the Kinsale gas field has been ongoing for some time, with the Stena Drilling-owned Stena Spey rig on-site from April 2021 to late in the year.
Several massive supply ships called to the Port of Cork during that time to provide logistics support to the operation.