Introduction
The Vanguard-class submarines form the backbone of the United Kingdom’s nuclear deterrent. Following the retirement of airborne nuclear weapons in 1998, Britain’s strategic deterrence relies entirely on its four Trident-armed SSBNs.
Commissioned between 1993 and 2001, the class includes HMS Vanguard, Victorious, Vigilant, and Vengeance.
Each displaces 16,000 tons submerged and measures 150 meters in length, making them the largest submarines ever built for the Royal Navy. They are powered by the Rolls-Royce PWR2 reactor and are armed with 16 Trident II D5 submarine-launched ballistic missiles (SLBMs), each capable of carrying up to eight warheads. Additionally, they are equipped with four 21-inch torpedo tubes for Spearfish torpedoes.
| Vanguard Class SPECIFICATIONS | |
|---|---|
| Length: | 149.9 m (491.8 ft) |
| Height: | 36 ft 3 in (11 m) |
| Width: | 12,8 m (42 ft) |
| Weight: | 14,000 tons surfaced 15,980 tons submerged |
| Armament: | 16 launch tubes for Trident missiles and four 21 inch torpedo tubes |
| Speed: | 18 knots on the surface 25 knots submerged |
| Powerplant: | Rolls-Royce PWR-2 pressurized water nuclear reactor |
| Crew complement: | 135 (14 officers) |
| Contractor: | Vickers Shipbuilding & Engineering, Barrow-in-Furness |
| Names of submarines: | VANGUARD (S28), VICTORIOUS (S29), VIGILANT (S30), VENGEANCE (S31) |
These submarines operate from Faslane Naval Base in Scotland and maintain a continuous at-sea deterrence (CASD) posture, ensuring that at least one is always on patrol. Britain’s single deterrent capability ensures a rapid response, with at least two additional submarines available for deployment while the fourth undergoes maintenance.
Description
Design
The Vanguard-class was originally conceived as an evolution of the Trafalgar-class, but the integration of the PWR2 nuclear reactor required a larger and more complex design. Unlike the Resolution-class, which was adapted from existing designs, the Vanguard-class was purpose-built as a ballistic missile submarine (SSBN), incorporating successful features from previous British nuclear submarines.
At 149.9 meters in length, with a 13-meter beam and a submerged displacement of 15,980 tons, the Vanguard-class is nearly twice the size of the Resolution-class, primarily due to the 16-tube Trident D5 missile compartment. The increased size allowed for a fourth deck, providing spacious living quarters and improved working conditions for the crew.
Despite this, space was limited due to the need to constrain length within existing dockyard facilities. To accommodate this, ballast tanks were wrapped around the ends of the pressure hull instead of maintaining a constant-diameter design, as seen in the U.S. Ohio-class SSBNs. While this solution controlled the submarine’s size, it resulted in a cramped engine room, which later presented operational challenges.
The Vanguard-class was the last British submarine designed by the Royal Corps of Naval Constructors, as the Astute-class that followed was designed by the shipbuilders. Each submarine features an anechoic noise-reduction coating on the outer hull to minimize acoustic detection.
Crew
Each Vanguard-class submarine operates with two separate crews, known as Port and Starboard. While one crew undertakes patrol duties beneath the ocean, the other conducts training exercises or takes leave ashore. Training includes seamanship, weapons handling, and sonar operation at the Faslane naval base.
A Vanguard submarine accommodates a crew of up to 130 sailors. They live across three decks spanning the vessel’s 150-metre length. The living spaces aboard are unusually spacious compared to earlier submarines. Enhanced domestic facilities and improved food quality help maintain crew morale during extended submerged operations.
The submarine’s advanced air purification system and freshwater production from its nuclear plant further ensure comfort and health during patrols. Despite these comforts, the crew experiences strict limitations on communication, with telephone and internet access significantly restricted to maintain secrecy.
Initial operational plans reportedly aimed to keep three submarines in active service simultaneously, supported by a total of five crews, rather than the expected six.
In 1998, the Labour government announced plans to move from double crews to a single-crew system, aiming to reduce costs and ease recruitment pressures. In May of that year, HMS Vanguard temporarily operated with one enhanced crew of 200 sailors, instead of the usual 135. However, this single-crewing experiment was short-lived, and the double-crew system ultimately remained in place.
Missiles
Each Vanguard-class submarine carries 16 U.S.-made Trident II (D5) submarine-launched ballistic missiles (SLBMs). These three-stage, rocket-propelled missiles are 44 feet long, weigh 130,000 pounds, and have a range of 4,000 nautical miles.
Each missile can be armed with up to three multiple independently targetable reentry vehicles (MIRVs), meaning a single submarine can carry up to 48 nuclear warheads. The warheads are a British variation of the U.S. W76 design, enclosed in a U.S. Mk-4 reentry vehicle.
The United Kingdom does not own the Trident missiles outright but leases them from a pool of 58 SLBMs shared with the United States Navy at the Strategic Weapons Facility Atlantic (SWFLANT), Kings Bay, Georgia. Missiles used by a British SSBN may later be assigned to a U.S. Navy SSBN, and vice versa. After receiving their missiles in Kings Bay, British submarines sail to the Royal Naval Armaments Depot at Coulport, where the UK-designed and UK-manufactured warheads are fitted.
British SSBNs conduct their missile flight tests at the U.S. Eastern Test Range off the coast of Florida. The UK’s Trident warheads, known as Holbrooke Mark 4s, were tested three times at the Nevada Test Site.
Since the 2010 Strategic Defense and Security Review (SDSR), British submarines on patrol carry no more than eight operational Trident missiles, armed with a total of 40 nuclear warheads. These missiles remain in a detargeted mode, meaning targeting data must be loaded before launch, reducing their alert status to several days’ notice instead of immediate readiness.
Sonar and Electronics
The Vanguard-class was the first Royal Navy submarine equipped with an advanced computerized Submarine Command System (SMCS). This multi-screen command system employs eleven highly advanced computers connected by a high-capacity fibre-optic link. SMCS provides over twenty times the processing power of earlier systems, improving cost efficiency and reliability. The class also features the Sonar 2054, a unique system employing hydrophone and transducer arrays twice as large as any previously operated by the Royal Navy.
The Type 2054 sonar comprises three elements initially designated separately: the Type 2043 active/passive bow sonar, the Type 2044 reelable towed array, and the Type 2045 intercept sonar. These elements are integrated into a fully federated system.
Signal processing is entirely digital, converting signals into digital form before transmission to the beam-former. The sonar suite features five consoles, each equipped with two 17-inch display screens and touch-sensitive plasma control panels. Plessey (now part of Marconi) supplied the bow sonar, beam-former, and signal processor; Marconi provided the intercept sonar, and Ameeco supplied the towed array.
Navigation systems include the Ship’s Inertial Navigation System (SINS) Mk 2 and the Navigation radar utilizes the Kelvin Hughes Type 1007 (I-band) radar.
Additionally, the class introduced the first British submarine use of optronic masts, allowing relocation of the operations room to a more spacious lower deck. It is equipped with Pilkington Optronics CK 51 search periscope and Pilkington Optronics CH 91 attack periscope.
Combat data management is handled by the BAE Systems SMCS NG, and weapon control employs the Ultra Electronics Outfit SWIM 2. Physical countermeasures include External Launched Countermeasures (SCAD 101) and three SSE Mk 10 launchers. Electronic support measures feature the Thales UAA4 intercept system.
Propulsion
The Vanguard-class submarines are powered by the PWR2 reactor, a pressurized water reactor developed in the United Kingdom specifically for ballistic missile submarines. Designed and built by Rolls-Royce, the PWR2 generates 145 MWt of thermal power and drives two GEC steam turbines, which in turn power a single pump-jet propulsion system delivering 20.5 MW of propulsive power.
Compared to its predecessor, the PWR1, the PWR2 offers 50% more power and 50% longer operational life, significantly extending the submarines’ time between refits and refueling.
The PWR2 also enhances stealth capabilities. It uses natural circulation at low power, reducing noise levels compared to earlier reactors. This, combined with improved power distribution, makes the Vanguard-class submarines inherently quieter and more survivable in hostile environments.
Initially, the Core G reactor core used in the Vanguard-class submarines provided nearly three times the lifespan of the earlier Core A, which was utilized in the previous Resolution-class SSBNs. This ensured these submarines to require refueling only every 8 to 9 years, allowing the Royal Navy to maintain three boats in active service at all times with fewer crews.
However, during their first overhaul, all four Vanguard-class submarines were fitted with a new long-life reactor core known as Core H. Core H was specifically designed to last for the remainder of the submarines’ service life without requiring refueling.
Torpedoes
In addition to their Trident II D5 ballistic missiles, the Vanguard-class submarines are equipped with four 21-inch (533 mm) torpedo tubes for Marconi Spearfish heavyweight torpedoes. These torpedoes provide anti-submarine and anti-surface warfare capabilities, ensuring the submarines can defend themselves against enemy warships and submarines.
The Spearfish is the Royal Navy’s primary heavyweight torpedo, designed to counter high-speed, deep-diving submarines and large surface vessels. It features dual guidance, using both wire guidance and active-passive sonar homing.
Its speed and range vary depending on operational needs, reaching 65 knots with a range of 26 km or 50 knots with a range of 31.5 km. At its maximum, it can travel at 60 knots for 35 nautical miles. Powered by a HAP-Otto fuel-powered Sundstrand 21TP01 gas turbine engine, it uses a pump-jet propulsion system for high-speed maneuverability.
The Spearfish torpedo carries a 300 kg directed-charge warhead capable of breaking the keel of a 50,000-ton ship by creating an underwater gas bubble explosion beneath the target. Weighing approximately two tons, it delivers firepower equivalent to a 550 lb bomb. These torpedoes ensure that the Vanguard-class submarines remain a formidable threat in underwater combat, even though their primary mission is nuclear deterrence.
Construction
The Vanguard-class submarine program was the largest, most complex, and most expensive military construction effort in Western Europe at the time. It was initiated after the British government decided on 15 July 1980 to procure the US Trident I (C4) missile system. However, on 11 March 1982, this was upgraded to the more advanced Trident II D5 system. These missiles would be deployed aboard a fleet of four submarines, with construction beginning in the mid-1980s.
All four submarines were built at Barrow-in-Furness, in a purpose-built indoor shipbuilding facility—the largest in Europe—located at the Devonshire Dock. The project’s estimated cost was $19.8 billion. Lord Chalfont, Chairman of Vickers, compared the Vanguard-class to the engineering challenge of landing a man on the Moon, emphasizing the advanced technology involved.
| No. | Name | Builder | Keel Down | Launched | Comm. |
|---|---|---|---|---|---|
| S28 | Vanguard | Vickers Shipbuilding & Engineering, Barrow-in-Furness | 3 Sep 1986 | 4 Mar 1992 | 1 4 Aug 1993 |
| S29 | Victorious | Vickers Shipbuilding & Engineering, Barrow-in-Furness | 3 Dec 1987 | 29 Sep 1993 | 7 Jan 1995 |
| S30 | Vigilant | Vickers Shipbuilding & Engineering, Barrow-in-Furness | 1 6 Feb 1991 | 15 Oct 1995 | 2 Nov 1996 |
| S31 | Vengeance | Vickers Shipbuilding & Engineering, Barrow-in-Furness | 1 Feb 1993 | 19 Sep 1998 | 27 Nov 1999 |
The first submarine, HMS Vanguard, was ordered on 30 April 1986, and its keel was laid in September 1986 in a ceremony attended by the Prime Minister. The second, HMS Victorious, was ordered on 6 October 1987, followed by HMS Vigilant on 13 November 1990. A decision on the fourth boat was delayed until after the 1992 general election, with HMS Vengeance finally ordered on 7 July 1992. Its keel was laid in February 1993.
Operative Service
The Vanguard-class submarines entered service in the mid-1990s, forming the backbone of the United Kingdom’s strategic nuclear deterrent.
HMS Vanguard was commissioned in August 1993, followed by HMS Victorious in January 1995, HMS Vigilant in November 1996, and HMS Vengeance in November 1999. All four submarines became part of the 1st Submarine Squadron (SM1), based at the Clyde Submarine Base, Faslane. The first Trident patrol began in December 1994, while the last Polaris submarine, HMS Resolution, was decommissioned in August 1996, completing the transition to Trident.
In November 1998, HMS Vanguard became the first Royal Navy SSBN to visit Gibraltar, demonstrating expanded operational capabilities. On 4 February 2009, HMS Vanguard was involved in a collision with the French SSBN Le Triomphant, sustaining superficial damage.
On 3 April 2013, the Prime Minister visited HMS Victorious by Royal Navy helicopter as it returned up the Firth of Clyde, commemorating the completion of the Royal Navy’s 100th Vanguard deterrent patrol.
Demonstration and Shakedown Operations (DASO)
Before entering operational service and after major overhauls, each Vanguard-class SSBN conducts Demonstration and Shakedown Operations (DASO) to verify system integrity. The Royal Navy has conducted twelve DASO firings of Trident II D5 missiles, ensuring certification for deployment:
| # | Date | Submarine | Missile | Status |
|---|---|---|---|---|
| 1 | 26 May 1994 | HMS Vanguard | Trident D5 | Successfull |
| 2 | 19 June 1994 | HMS Vanguard | Trident D5 | Successfull |
| 3 | 24 July 1995 | HMS Victorious | Trident D5 | Successfull |
| 4 | 22 August 1995 | HMS Victorious | Trident D5 | Successfull |
| 5 | 10 October 1997 | HMS Vigilant | Trident D5 | Successfull |
| 6 | 10 October 1997 | HMS Vigilant | Trident D5 | Successfull |
| 7 | 21 September 2000 | HMS Vengeance | Trident D5 | Successfull |
| 8 | 10 October 2005 | HMS Vanguard | Trident D5 | Successfull |
| 9 | 26 May 2009 | HMS Victorious | Trident D5 | Successfull |
| 10 | 23 October 2012 | HMS Vigilant | Trident D5 | Successfull |
| 11 | 20 June 2016 | HMS Vengeance | Trident D5 | Failure |
| 12 | 30 January 2024 | HMS Vanguard | Trident D5 | Failure |
These tests confirm the submarines’ combat readiness before they return to patrol duty.
Maintenance, Upgrades, and Extended Service Life
Each submarine undergoes a Long Overhaul Period and Refuel (LOP(R)) approximately every 10–12 years at Devonport Dockyard, incorporating reactor refueling, sonar upgrades, and electronic warfare enhancements:
| Location | Submarine | Start | End | Comments |
|---|---|---|---|---|
| HM Naval Base Devonport | HMS Vanguard | Feb 2002 | Jun 2005 | Long Overhaul Period and Refuel (LOP(R)) |
| HM Naval Base Devonport | HMS Victorious | April 2005 | May 2008 | Long Overhaul Period and Refuel (LOP(R)) |
| HM Naval Base Devonport | HMS Vigilant | October 2008 | March 2012 | Long Overhaul Period and Refuel (LOP(R)) |
| HM Naval Base Devonport | HMS Vengeance | March 2012 | December 2015 | Long Overhaul Period and Refuel (LOP(R)) |
| HM Naval Base Devonport | HMS Vanguard | December 2015 | May 2023 | Life-extension (LIFEX) |
| HM Naval Base Devonport | HMS Victorious | May 2023 | - | Life-extension (LIFEX) |
During their first overhaul, all submarines were fitted with a new long-life reactor core (Core H) at the newly constructed D154 refuelling and defuelling facility at Devonport.
The sonar system modernization included an open architecture upgrade comparable to the US Navy’s Acoustic Rapid COTS Insertion (ARCI) program.
Additional upgrades included the installation of the Submarine Acoustic Warfare Control System (SAWCS) and enhancements to the UAP-3 radar electronic support measures (ESM).
Originally, Vanguard was scheduled for retirement in 2022, but instead, the class will receive additional refits, extending service for 5 to 10 more years until the Dreadnought-class SSBNs replace them.
Vanguard Replacement
The Vanguard-class submarines will be replaced by the Dreadnought-class, the United Kingdom’s largest and most expensive defense project, with an estimated cost of £41 billion (US$52.5 billion).
The Dreadnought program was first announced on 4 December 2006, and by February 2011, the UK government confirmed that four new submarines would be built. On 18 July 2016, the House of Commons formally authorized the program, and the first steel was cut on 6 October 2016.
The Dreadnought-class will continue the Continuous At-Sea Deterrence (CASD) mission, carrying Trident II D5 SLBMs, in cooperation with the U.S. Navy’s Columbia-class SSBN program.
Unlike the Vanguard-class, which carries 16 missile tubes, the Dreadnought-class will have 12 missile tubes but a larger displacement of 16,900 tons due to advanced silencing measures.
It will be powered by the new PWR3 reactor, likely a natural circulation type, and will use a turbo-electric drive with a pump-jet propulsion system for increased stealth.
The program entered Delivery Phase 3 in March 2022, with a budget of £10 billion (US$12.5 billion). This phase includes the completion of HMS Dreadnought, the first boat in the class, and the start of sea trials in the late 2020s.
Most of Dreadnought’s major components, including its 12 missile tubes, have been manufactured, and hull sections are now being assembled at BAE Systems’ Devonshire Dock Hall in Barrow-in-Furness.
Construction of the second submarine, HMS Valiant, is well underway, while work on the third, HMS Warspite, began on 9 February 2023. The final boat, HMS King George VI, will follow.
Efforts are also underway to develop support infrastructure to ensure a smooth transition when the Dreadnought-class enters service, replacing the Vanguard-class in the 2030s.
Further Reading
Bibliography
- Saunders, S., Philpott, T. (2015). Jane’s Fighting Ships 2015 2016: Yearbook. United Kingdom: Ihs.
- Friedman, N. (2020). British Submarines in the Cold War Era. United Kingdom: Pen & Sword Books.
- Jane’s Major Warships. (1997). United Kingdom: Jane’s Information Group.
- Jinks, J., Hennessy, P. (2015). The Silent Deep: The Royal Navy Submarine Service Since 1945. United Kingdom: Penguin Books Limited.
- Croddy, E. A., Wirtz, J. J. (2005). Weapons of Mass Destruction: An Encyclopedia of Worldwide Policy, Technology, and History [2 Volumes]. United Kingdom: Bloomsbury Publishing.
- Skiba, R. (2024). Submarine Design and Construction Fundamentals. (n.p.): After Midnight Publishing.
