In June 2011 DLT were awarded the contract by Swiber Offshore Construction Services to design and supply two synchronized hydraulic jacking systems for use in the wet mating of the 12,000 tonne process platform (PP) and the 7,000 tonne living quarter platform (LQ) for ONGC's B193 oil/gas process complex in the Arabian Sea, located 75 km offshore from Mumbai in a water depth of 70m. Both systems were delivered to the customer in early 2012 and are scheduled to be used for the wet mating float over operations in late 2012.

The float over jacking system has been designed by DLT for maximum safety, flexibility for future use, and for economic transport between sites in standard shipping containers. Each of the two systems is made up of identical 1250 tonne 3m stroke hydraulic rams powered by four outlet electrically powered hydraulic power packs which have been sized for a full load lifting speed of up to 50 mm/minute and a fast full load lowering speed of up to 1000 mm/minute. Central monitoring and control is provided by our DL-P40 CANbus heavy lifting computer control system, which is sufficiently accurate to be used for weighing the top sides prior to load out.

On the PP there are 16 No 1250 tonne 3m stroke rams arranged into four groups of four rams, as shown below. On the LQ there are 12 No 1250 te 3m stroke rams arranged in four groups of three rams. The rams have been specially designed to work with up to 8% side load at full extension. As all the rams and power packs are identical they can be used in any configuration for future operations where it may be necessary to have greater lifting capacity and more than four support points. The main consideration in the design of the system has been the safety and security of the float over wet mating operations, which has been achieved by including a high level of redundancy. The system has been designed to be able to complete the wet mating operation in the event that any one ram in each support group completely fails, any one power pack completely fails or even if the central computer control system completely fails. In each of these cases there are back up systems in place to take over and complete the operation with the minimum of delay.