Power system colossus Rolls-Royce has bagged an order to design and supply power and propulsion systems for two of Island Offshore's supply vessels worth £20m. The deal not only involves the ship design but also includes a fully integrated and highly efficient diesel-electric power and propulsion system featuring four Rolls-Royce Bergen engines to power two Azipull thrusters, the company said. Island Offshore's UT 776 CD ship is designed to transport essential supplies to and from offshore oil and gas platforms. Rolls-Royce said the two supply vessels will be built by STX OSV at its Brevik shipyard in Norway and is expected to deliver in 2013. Shares of the engine maker fell 1.6% to 635.5p in London, in line with the movement on the benchmark index and its peers in the manufacturing industry.AR