Rolls-Royce has won a contract to convert the tankship 'Bergen Viking' to run on engines powered by natural gas, replacing the current diesel engines. Rolls-Royce Plc has won a contract to convert the merchant ship Bergen Viking to run on engines powered by natural gas, replacing the current diesel engines. The Norwegian ship owner Bergen Tankers AS has chosen gas engines and accompanying systems from Rolls-Royce for this upgrade, to provide a more environmental friendly and fuel efficient ship.