First practice dive

The Navy’s newest hunter-killer submarine HMS Anson (S123) has completed what a submarine should do – submerge – for the first time.

HMS Anson (S123)
Hunter-killer HMS Anson (S123) completes first practice dive in dock

The fifth Astute-class boat – £1.3bn of cutting-edge underwater naval power and technology – has successfully come through her first dive in the safety of a dock in Barrow.

The trim dive – carried out over two days – allows architects, experts and engineers calculate the boat’s precise weight, stability and centre of gravity, all key factors in Anson’s performance when she formally joins her four older sisters already in service with the Royal Navy’s submarine flotilla.

The dock at BAE Systems’ Barrow-in-Furness yard – where HMS Anson (S123) has been built over the past 11 years – features a giant chasm or ‘dive hole’.

Long and wide enough to accommodate a Royal Navy nuclear submarine, even at 25 metres (82 feet) it’s not quite deep enough to cover an A-class boat entirely, but it does leave only the conning tower and tailfin protruding from the cold waters of the Devonshire Dock.

The dive is a slow process as the 60 crew, engineers and shipwrights check for the hull’s watertight integrity and move around trollies collectively carrying 16 tonnes of lead weights so naval architects can confirm the stability of the 97-metre/318-foot-long nuclear submarine at sea.

«The start of the trim and basin dive is a key step in the commissioning of HMS Anson», said the boat’s first Commanding Officer, Commander David ‘Bing’ Crosby. «This successful first dive of the RN’s newest Fleet submarine is a direct result of weeks of intense, driven, joint team progress, in particular since Christmas».

Initial feedback from the test dive is a resounding thumbs up, allowing the BAE-Anson team to push ahead with the remainder of her testing and commissioning programme, preparing the boat for her maiden voyage.

Commander Crosby continued: «All involved should be very proud; the entire enterprise has again come together to achieve this evolution safely and on date – clear evidence of our joint approach and demonstrates what we can achieve when we all pull together. I would like to thank my team who have all worked wonders over the last few weeks to support and assure this event».

John Moorby, BAE Systems Submarines Astute Programme Director, hailed «a significant milestone in the submarine’s test and commissioning phase».

He added: «It demonstrates the continued successful collaboration between BAE Systems, the Submarines Enterprise, and our suppliers on delivering this national endeavour for the UK Royal Navy».

That national endeavour continues – not just with completing HMS Anson (S123), but also the sixth and seventh boats in the Astute-class, HMS Agamemnon (S124) and HMS Agincourt (S125), and HMS Dreadnought, the first of the next-generation nuclear deterrent submarines, all under construction in the gigantic Devonshire Dock Hall which dominates the Barrow skyline.