Royal Navy's Newest Submarine Goes Under Water for the 1st Time

The UK's newest nuclear submarine has successfully submerged for the first time at BAE Systems in Barrow, Cumbria.

The Royal Navy crew achieved the major milestone as part of HMS Agamemnon’s ‘trim dive’, a three-day period of testing in the town’s Devonshire Dock to prove the 7,400-tonne, 97-metre-long attack vessel’s stability and safety. 

The process, which comes shortly after King Charles III officially commissioned the Astute class submarine into the Royal Navy, is a key moment in the lead up to its departure from Barrow to join her sister boats in the fleet, based at His Majesty's Naval Base, Clyde. 

"This trim dive is the culmination of months of hard work. I'd like to thank all teams involved for their commitment and professionalism."

"We’re incredibly proud of the contribution we’re making to the nation’s security and Barrow’s long and distinguished heritage as the home of UK submarine design and build." Pete Tumelty, Astute Programme Director, BAE Systems’ Submarines business

"The trim and basin dive is a key step in the commissioning of HMS Agamemnon. This period enables us to set the boat’s internal weight, prove her water-tight integrity, test sensors and put some of our systems through their paces ahead of sailing for the first time."

"It takes a great deal of planning and preparation to achieve this key step and all involved should be very proud of the part they have played." Commander David ‘Bing’ Crosby, HMS Agamemnon Commanding Officer

Alongside the build of seven Astute class submarines – of which HMS Agamemnon is the sixth – BAE Systems is also constructing four Dreadnought class boats in partnership with the wider Defence Nuclear Enterprise.

The Dreadnought vessels, due to enter service from the early 2030s, are the replacement for the Vanguard-class submarines, which currently deliver the Continuous At Sea Deterrent (CASD) for the Royal Navy. The critical role underpins the nation’s defence as the ultimate security guarantee and sees at least one of the boats deployed in an unknown location at sea every minute of every day.

"The successful completion of HMS Agamemnon's trim dive marks a pivotal milestone in our mission to safely deliver available and capable submarines to the Royal Navy in defence of our nation."

"This achievement reflects the exceptional collaboration between the SDA and our partners across the Defence Nuclear Enterprise, demonstrating our unwavering commitment to supporting the UK’s nuclear deterrent as a national endeavour." Henry Musgrave, Head of Astute Delivery Team, Submarine Delivery Agency

Design work is also continuing on the future nuclear-powered AUKUS attack submarines as part of an agreement between the UK, the US and Australia.

BAE Systems has grown its submarines workforce from 10,700 in 2023 to 15,000 today to support the healthy order book and it is expected to reach 17,000 in the coming years.