Submarine, underwater test

The Royal Navy’s newest nuclear-powered attack submarine, HMS Agamemnon,

has successfully submerged for the first time during trials at BAE
Systems’ Barrow-in-Furness shipyard, according to the company. The
three-day “trim dive” in Devonshire Dock tested the 7,400-tonne
vessel’s stability, buoyancy, and watertight integrity ahead of its
departure from Barrow to join the Royal Navy’s fleet at His Majesty’s
Naval Base Clyde.

 UK Defence Journal 13th Oct 2025

 https://ukdefencejournal.org.uk/new-british-nuclear-attack-sub-submerges-for-first-time/

 Portsmouth News 13th Oct 2025

 https://www.portsmouth.co.uk/news/defence/royal-navy-hms-agamemnon-first-dive-5357265