Royal Navy’s Anson Astute-Class Sub Completes Trim Dive

BAE Systems said the Royal Navy’s fifth Barrow-built Astute-class submarine Anson completed its first trim dive in the town's Devonshire Dock.

The operation saw Anson submerge completely beneath the surface of the water while crew tested on-board systems. This successful exercise proved the safety and stability of the 7,400-tonne, 97m-long attack submarine, the company said.

Commanding Officer of Anson, Commander David 'Bing' Crosby, said: "The trim and basin dive is a key step in the commissioning of HMS Anson. This period will enable us to set the boat’s internal weight, prove her water-tight integrity, test sensors and put some of our systems through their tests ahead of sailing for the first time.”

A 'trim dive' is done to complete a number of tests. The most important is to help engineers establish the vessel's centre of gravity and precise weight.

More than 60 crew members were on board as part of the exercise, which saw tonnes of ballast taken aboard to assist in testing the vessel's stability.

Anson was officially named in December 2020 and launched in April 2021. HMS Astute, HMS Artful, HMS Ambush and HMS Audacious are already in service with the Royal Navy. The sixth and seventh Astute submarines, Agamemnon and Agincourt, are at different stages of construction at the Barrow shipyard.

As well as the Astute Class, BAE Systems is delivering the Dreadnought submarines for the Royal Navy and undertaking early phase concept design work on the replacement for the Astute class.