Lifting equipment manufacturer Modulift has supplied two large spreader beams to ST3 Offshore's terminal in Poland, which are being used to lift wind (turbine) jacket foundations.
The spreader beams - two 8 m-long MOD 400/600s - will form part of a rig that will be used to lift and position 20 jackets onto barges bound for Cuxhaven, Germany; the jackets will eventually be installed at the Borkum Riffgrund 2 offshore wind farm.
The two MOD 400/600s are being used in an inverted configuration above another Modulift beam, an 800/1000, which was hired from Schmidbauer. The beams combine with shackles and other rigging gear, including delta plates, to form the rig beneath the hooks of a rail-mounted, 117m-high, 1,400-tonne capacity gantry crane.
Each jacket foundation weighs 700 tonnes and measures 52 m high. Each barge can transport three jackets per voyage.
John Baker, sales and marketing director at Modulift, said that the top two 400/600 beams are used in an inverted configuration to utilise the four hoist hooks on the gantry crane. This allows the lower slings to come down to a single point on top of the lower 1,000-tonne capacity beam. Below that, two delta plates and a horizontal sling create the vertical angle for the bottom slings, which attach the rig to the top of each jacket.
"Modulift spreader beams are put into compression when loaded so another beam wouldn't have been suitable at the bottom of the rig between the delta plates because the forces applied are tensile rather than compressive. A wire rope grommet acted as a tie sling between the delta plates and created the vertical sling angle for the bottommost slings in the rig," Baker explained.
Modulift says that the first phase of the loadout is ongoing and the lifting rig will remain in Szczecin for the duration of the project.
The gantry crane lifts the second of three jacket foundations to be loaded onto the awaiting vessel.