THE Royal Navy unveiled its latest nuclear-powered attack submarine yesterday, as HMS Artful was christened in a ceremony at Barrow-in-Furness.The Astute class vessel, which weighs 7,400 tonnes and is 97 metres long, was officially named in front of thousands of guests inside BAE Systems' giant Devonshire Dock Hall submarine construction facility.It is the third vessel of its class, with HMS Astute and HMS Ambush ahead of it. The other submarines in the class in various stages of design or build are Audacious, Anson, Agamemnon and Ajax. The Ministry of Defence says that while not nuclear- armed, the Astute submarines have greater conventional missile firepower, the latest communications equipment and better stealth technology than predecessors.Amanda Lady Zambellas, wife of First Sea Lord Admiral Sir George Zambellas, christened the submarine in classic tradition, breaking a bottle on her bow - beer from a local Cumbrian breweryAdmiral Zambellas said: "Today's naming ceremony in Barrow for Artful adds another capable nuclear submarine to the gathering momentum in the Astute class. Ahead of her, HMS Astute and HMS Ambush are already being pressed hard towards operational use, contributing to the wider renaissance in the UK's naval equipment programme and adding to the Royal Navy's operational authority."Artful will remain in the Barrow yard to complete a series of commissioning activities, before being launched in early 2014.She is the second Royal Navy submarine to hold the name. The first HMS Artful was constructed by Scotts Shipbuilding and Engineering in Greenock in 1947.