HMS ASTUTE (Some Basin Trial Photographs) The Royal Navyâ€™s newest and most advanced nuclear submarine, Astute, is taking her first dive for an underwater test of her systems. The â€˜Trim and Basin Diveâ€™ is taking place in Devonshire Dock, Barrow, over two days, and involves submerging Astute in a dive hole large enough for the 100M-long, 7400 tonne boat. The dive is the first time that the submarine has been fully submerged, and provides the opportunity to test the submarineâ€™s underwater stability and systems. 25 of her crew are on board alongside BAE Systems technicians to carry out the tests. Tests include trials of various boat systems and equipment including the mechanism that releases an emergency buoy, the emergency escape tower, and various hydraulics and electrical systems. Lord Drayson, Minister for Defence Equipment and Support, said: â€œThis is an important step on the road to preparing Astute for service. These submarines are hugely impressive vessels, and will provide the Royal Navy with a world class capability.â€ After completing the dive, Astute will be docked and taken back into Devonshire Dock Hall. The next stage will be to calculate her stability, weight and buoyancy.