The British navy is teaming up with the US to build a new 'Dreadnought' for a totally different battle at sea

• The British Royal Navy is building a new class of nuclear-powered ballistic-missile submarines.
• The British subs will have the same missile compartment as the US Navy's new missile subs.
• The name of the new subs recalls the first Dreadnought, a battleship that redefined naval warfare.

In 1906 the British Royal Navy commissioned HMS Dreadnought, a battleship that changed how surface warships were designed and sparked a naval arms race.

Armed with five turrets bearing twin 12-inch guns and featuring new technologies like steam turbines and electronic fire-control equipment, HMS Dreadnought became the standard on which future battleships were based and separated the "pre-dreadnought" and "dreadnought" eras.

Long after the battleship's reign came to an end, the name Dreadnought is still a defining one. The Royal Navy's first nuclear-powered submarine, in service from 1963 to 1980, was also called HMS Dreadnought.

Now, more than 100 years after the first Dreadnought, another is in the works. This one, the first of a new class of nuclear-powered ballistic-missile submarines, will again usher in a new era of warship for Britain.

At-sea deterrent

Britain's new class of nuclear-powered ballistic-missile submarines, designated as SSBNs, will fill a looming gap in the country's nuclear deterrent.

Whereas other nuclear-armed countries employ a triad of delivery systems — ground-launched, air-launched, and sea-launched — to ensure their nuclear capability will survive an attack and thus guarantee a credible nuclear deterrent, Britain has relied solely on submarine-launched ballistic missiles since 1998, when it retired its air-dropped nuclear gravity bombs.

The Royal Navy has had at least one SSBN on patrol as part of Operation Relentless, Britain's continuous at sea deterrent, since 1969, making it the country's longest ongoing military operation. The current British SSBN force is made up of four Vanguard-class subs, which were built between 1986 and 1998.

The strain of decades of near-constant deployments has taken a toll on the Vanguards. Originally meant to serve for 25 years, the subs have had their service lives extended three times. Their overall lifespan is now expected to be 37 to 38 years.

In 2007, the British Parliament approved a plan for four new SSBNs to replace the Vanguards. After years of design work, construction on the first boat, HMS Dreadnought, began in 2016.

To ensure successful and efficient construction and delivery of the new class, the Ministry of Defense created the Submarine Delivery Agency in 2017 to serve as an executive agency responsible for procurement, in-service support, and decommissioning of all Royal Navy nuclear submarines.

A year later, the two companies contracted to build the Dreadnought, BAE Systems and Rolls Royce, formed the "Dreadnought Alliance," a commercial arrangement that ensures constant communication and collaboration between the companies, including on things like a common cost model, mutually agreed scheduling and breakdown of work, and reporting procedures.

The Dreadnought class

At about 500 feet long and with a displacement of 17,200 tons, the Dreadnoughts will be the largest submarines ever built by the UK. Each boat will have a lifespan of at least 30 years.

Each Dreadnought will be powered by the PWR3, a new nuclear reactor built by Rolls-Royce. They will also have X-form rudders and a new turbo-electric drive that powers an electric motor that drives an improved pump-jet propulsor, likely making them quieter than their Vanguard-class predecessors.

Along with the quieting features of their propulsion systems, the Dreadnoughts will have an angular design meant to deflect active sonar waves, making them stealthier. Concept imagery indicates that the Dreadnoughts will also be coated with anechoic tiles, which are designed to absorb incoming active sonar waves and reduce noise from the sub that could be picked up by passive sonar.

The Royal Navy also plans to equip its Dreadnought subs with optronic masts — a high-tech replacement for the traditional periscope that is already in use on its Astute-class submarines.

The Dreadnoughts will have four 21-inch torpedo tubes and carry Spearfish heavyweight torpedoes. Their main armament, however, will be 12 Trident II D5 ballistic missiles — four fewer than on the Vanguard-class subs — carrying Mk4/A "Holbrook" nuclear warheads.

The missiles will be stored and launched from the Common Missile Compartment. The CMC is a joint US-UK defense project begun in 2008 to create a common launch system for all future American and British SSBNs. Each CMC contains four missile silos. Dreadnoughts will be equipped with three CMCs, while the US Navy's Columbia-class boats will have four.

Apart from the CMC project, the UK is also involved in the US Navy's Trident II D5 service-life extension program, which aims to stretch the missile's service life as far as the early 2060s. The British government previously indicated that its Tridents will need to be replaced in the 2040s.

The future fleet

Four Dreadnought-class subs will be built: Dreadnought, Valiant, Warspite, and King George VI. Construction of Valiant started in 2019 and work on Warspite began in February.

In May 2022, the Ministry of Defense announced that Dreadnought had entered Delivery Phase 3, during which the sub will eventually leave the BAE shipyard in Barrow-in-Furness for sea trials, yielding lessons that will be applied to construction of other Dreadnought-class subs. The Royal Navy plans to commission HMS Dreadnought sometime in the early 2030s.

In addition to being the largest British subs ever, the Dreadnought class will be one of the most expensive defense projects in British history.

Building the four subs is expected to cost a little over $39.5 billion, a total that includes inflation over the 35-year life of the program. The British government has also set up a contingency fund of about $12.75 billion, money that can be "re-profiled" to keep the program on track. The MoD has already accessed about 20% of the fund.

While British lawmakers have expressed concern that the Ministry of Defense would view the contingency fund as "a blank cheque, freeing it from the need to control costs," the ministry said in its 2022 update to Parliament, published in March, that the program was still on schedule and within its cost estimate.