The job required Modulift modular spreader beams, to lift the 50t MT30 turbines onto the vessel. Three spreader beams were used to the turbine in a one-over-two formation. Instead of using the manufacturers off-the-shelf range the beams were specially made in order to meet the custom strut lengths specified by Rolls-Royce.
The spreader beams needed to be proof load tested for the project. The testing was conducted using Moduflift’s own compression test rig. Once all the spreader beams were assembled they were individually loaded in to the compression test rig and the designated proof load was applied, which for this project was +25% of the safe working load (SWL).
Testing of all the spreader beams was successfully completed without any issues and a final posttest Magnetic Particle Inspection (MPI) was conducted which verified that there were no weld defects. The drop links for the spreader beams were then proof load tested in Modulift’s own tension test rig using the same proof load factor as the spreader beams.
Designing the rig plan was a job that required a high level of accuracy, as any technical or mechanical mistakes could result in the gas turbine capsizing as it was being lifted into place on the vessel by the Goliath crane. The turbine had a 75/25 offset centre of gravity although the lifting rig would need to raise it in a level position. Despite these challenges Modulift’s design proved to be precise enough and the turbine was lifted level at 0.2 degrees.
The Queen Elizabeth is the largest British Naval ship ever built and at 36mw the MT30 is the world’s most powerful turbine, providing two thirds of the power the ship requires. The carrier is expected to leave Roysyth in 2014, before taking part in Royal Navy sea trials.
Rigging equipment review
