The rejuvenation of the British Royal Navy's fleet is still ongoing, and recently, they achieved a significant milestone. The Royal Navy's newest nuclear attack submarine, HMS Agamemnon (S124), successfully completed its maiden dive in mid-October 2025. This momentous event took place at BAE Systems' facility in Barrow-in-Furness, Cumbria.
- The dive, known as the Trim Dive, is a crucial testing phase, arguably a crucial step before the Astute-class submarine begins its open-sea trials. Its purpose is to verify the hull integrity and ensure the submarine's pressure hull is completely watertight and secure.
As the sixth ship of the Astute class, the Agamemnon carries a formidable arsenal. It is equipped with six 533 mm torpedo tubes for a total of 38 weapons. Its primary armament includes Tomahawk Block V missiles manufactured by Raytheon Technologies (now RTX) and Spearfish heavy torpedoes, typically used to counter high-speed, deep-sea submarine threats.
The Tomahawk Block V itself is capable of reaching speeds of around Mach 0.74 (subsonic) with a range of over 1,000 nautical miles (approximately 1,600 km). It has a conventional warhead weighing approximately 450 kg. The UK is the only other user of this missile besides the US.
- Meanwhile, the Spearfish heavy torpedo uses a Sundstrand gas turbine engine with a pump-jet propulsion system capable of reaching speeds of up to 80 knots (150 km/h) in the terminal attack phase. The Spearfish heavy torpedo is capable of striking targets at ranges exceeding 50 km and has an aluminized high-explosive warhead (approximately 300 kg).
A key part of the trials was the "trim and inclining experiment," which aimed to measure the submarine's center of gravity. Reportedly, a 16-ton lead pendulum was brought aboard and moved from side to side. This movement was also measured manually using a pendulum suspended between the decks. According to details provided by the UK Ministry of Defence, the results of these measurements were also used to calculate the submarine's exact weight and stability, indicating how the vessel would perform on duty.
Once operational, HMS Agamemnon will operate in various global maritime areas, as ships of her class do, for maritime defense, intelligence gathering, and support operations for Royal Marines special forces. However, her official homeport is not specifically mentioned in the search results, although ships of her class are typically based at Faslane, Scotland.
- In addition to HMS Agamemnon, BAE Systems is reportedly also building four Dreadnought-class submarines in partnership with the broader Defence Nuclear Enterprise.
- The Dreadnought-class submarines, scheduled to enter service in the early 2030s, will replace the Vanguard-class submarines, which currently perform the Continuous At Sea Deterrent (CASD) role for the Royal Navy.
The press release stated that the important role of these submarines is to support the country's defense as a guarantee of the highest security, where at least one of these submarines is deployed in an unknown location at sea every minute, every day.
- GlobalNews...