Modulift has provided a custom lifting beam, slings and shackles to Stockton Drilling for multiple lifts of a 28-tonne, 18 m long tunnel boring machine (TBM) offshore Portgordon, Scotland.
Stockton Drilling was utilising the TBM at the Beatrice Offshore Windfarm / Direct Pipe Landfalls (BOWL), installing steel landfalls for high-velocity cables.
The TBM was recovered from the sea after each drive using a remote disconnect module. Divers were then dispatched to the TBM's location to attach the 34-tonne capacity, 16.6 m long beam so a 120-tonne capacity crane, placed on a rented jack-up barge, could lift it out of the water and place it on a multi-cat for return to nearby Buckie Harbour.
Modulift was challenged with design and manufacture of a below-the-hook solution to lift the TBM from beneath the surface.
The TBM is made up of 10 modules that each has its own individual lifting points, all of which were to be utilised to provide equal loading and enable the machine to be lifted in one piece. The beam also had three top lifting points to facilitate rigging to the crane.
Modulift utilised counterweights to ensure the beam would stay level with the load on the seabed. It was also manufactured to withstand the dynamic forces present in the marine environment.
According to Modulift, Stockton has retained the beam for future use.