Although the platform has inbuilt natural buoyancy, its overall weight increased substantially during assembly due to additional steel work that was added to the rig during a re-fit. This meant that the rig would not be buoyant enough to float over the sill of the dock out into open sea.
UMC Engineering Director, Dave Richards said: “To solve this issue our marine engineers worked together with BARD Engineering on an arrangement of lift bags that we could effectively position and attach to the rig to keep it level and balanced whilst on its undocking programme.”
He continued “After four weeks of on-site project management and engineering support, we installed a total of 30 air lift bags which provided an additional 600 tons of buoyancy, and reduced the draft of the rig by 1.2m. This solution enabled us to successfully float the rig over the sill and out of the dock where we could remove the additional floatation bags and allow the rig to be towed to its final location.”
The rig was bound for the German Sector in the North Sea where it operates in conjunction with the offshore wind farm “BARD Offshore 1”, enabling renewable energy to be collected and transferred to land-based electrical distribution networks.
Dave Richards added: “UMC has gained experience in solving many unusual offshore rig problems with some unique and novel solutions. For instance, we recently designed and installed man-entry habitats to repair spud cans of a jack up rig severely damaged in Hurricane Katrina.