Engine developer Rolls-Royce said that it is trading in line with previous guidance, and expects sales to double over the next ten years. "The global markets that we address are starting to recover as expected and our view of the full year trading performance remains consistent with the guidance issued at our preliminary results in February 2011," said chief executive John Rishton.The group announced in February that it expects to grow underlying revenues "modestly" in 2011, as a slowdown in original equipment revenues in the Marine division is offset by services activity growth in the Civil aerospace and Marine businesses.As a result, "We remain confident in our ability to double revenues in the coming decade through organic growth alone," added Rishton.He also added that its €3.2bn joint public tender offer with German motor company Daimler for industrial engines group Tognum - announced in March - "would significantly accelerate the growth of our Marine and Energy businesses". Rolls said that the joint venture would create a market-leading portfolio of technologies and systems for the marine, transportation and distributed power generation sectors.---BC