This transformer rig is a highly sophisticated unit under final assembly at Belfast Docks. The rig weighs 7458 tonne and can only be towed. To reach its final destination, the platform has to cover 900 sea miles across the Irish Sea, English Channel and into the German North Sea.
The challenge was to engineer a solution to increase the net buoyancy of the platform to enable it to float over the sill of the dock into open sea. The rig is naturally buoyant but extra buoyancy was needed to get the platform out of the Harland and Wolff dry dock.
SeaTec carried out a detailed investigation and following discussions with the client, it was agreed to utilise a series of lift bags to provide an additional buoyancy of 600 tonnes. SeaTec designed the attachment points, specified all the additional equipment (including compressors, hoses, connectors and manifolds) and wrote the detailed procedures. A project manager was assigned to oversee the onsite operation, which included the use of SeaTec divers to inspect the connection of the bags to the rig and retrieval of the bags at completion. The whole operation was undertaken successfully and in line with the agreed schedule.