And, despite being 50 per cent bigger than the Swiftsure and Trafalgar subs she will replace, Ambush is quieter. Her propellers are said to make less noise than a baby dolphin — making her virtually undetectable to enemy vessels.
Of course, that is if enemy vessels can get near her. The submarine’s sonar and radar are so sensitive that she can detect ships a staggering 3,000 nautical miles away. It means that if she was sitting in the English Channel she would know if a ship left New York's harbour. A true titan of the deep, the £1.2billion warship will be launched at Barrow-in-Furness in Cumbria on Thursday.
But naval chiefs will nervously hope the newly-named craft will not suffer the same catalogue of disasters that has recently befallen her sister vessel, HMS Astute. Astute’s captain, Commander Andy Coles, was relieved of his duties after the submarine ran aground on a sandbank off the Isle of Skye in October.
During the rescue, a tug collided with the sub, causing £7million of damage. Last week, she limped back to her home port of Faslane after a mechanical failure at sea. Ambush will be unveiled and officially named by Lady Anne Soar, the wife of the Royal Navy’s Commander in Chief Fleet, Admiral Sir Trevor Soar.
After the ceremony, the awesome 7,400-tonne sub will be wheeled from her shed and lowered into the wet dock for further outfitting and testing. And having come in massively over-budget and five years late, the Navy is expecting nothing less than a top-of-the-range vessel.
More complex than the U.S. Space Shuttles and able to circumnavigate the globe without surfacing, Ambush is 291ft long — the same length as a football pitch — as wide as four double-decker buses and 12 storeys high. A typical patrol lasts ten weeks, but she could theoretically stay underwater for her entire 25-year lifespan.
HMS Ambush will carry 38 missiles — a mixture of Tomahawk cruise missiles, which have a range of 1,240 miles, and Spearfish heavyweight torpedoes to target other ships and submarines.
Her nuclear-powered engine will propel her through the water at more than 20 knots, allowing her to travel 500 miles a day. In this image released by the Navy, a section of the hull behind the conning tower has been intriguingly obscured for security reasons.
BAE Systems is building seven Astute-class subs. The £6.7 billion project is already £1.4 billion over budget, after being beset by problems and delays.