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DSEI 2023: Can the Royal Navy's submarine fleet handle the pressure?

12th September 2023 - 11:15 GMT | by Tim Fish in Auckland


HMS Anson departing for sea trials. Deliveries of the remaining two Astute-class submarines need to be completed within the next two or three years to prevent the RN's attack submarine force dipping too low (Photo: UK MoD/Crown Copyright)

The third and final instalment of Shephard’s focus on the UK Royal Navy (RN) examines the state of the submarine force. The SSN fleet is still in transition as the last Trafalgar-class boats retire and Astute-class boats struggles to get into service, and pressure on Vanguard-class SSBNs is increasing as the Dreadnought successor project gets under way following long delays.

Delivery of the RN's Astute-class SSNs has been a painful process going back decades. In February 2023 the fifth boat, HMS Anson (S123), left BAE’s shipyard at Barrow-in-Furness and is undertaking sea trials before being declared ready for service. 

Meanwhile the sixth and seventh boats Agamemnon (S124) and Ajax (S125) are still under construction and will not enter service until at least 2026. This is slow progress for a project that was first contracted in 1997.

A lack of submarine manufacturing experience and the technical challenges of building a new modern SSN meant that although production of first-of-class HMS Astute (S119) started in 2001 it was not commissioned until 2010. 

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The project has been hit with considerable cost-overruns and further technical issues related to the production of boat four, HMS Audacious (S122), resulted in a pause on the programme, adding to delays.

Meanwhile in May 2022 the Royal Navy decommissioned two Trafalgar-class submarines, HMS Trenchant and HMS Talent leaving just one, HMS Triumph, remaining. It will operate alongside the four Astute-class SSNs already in-service until it is also decommissioned in 2024-25. 

The seven Trafalgar-class SSNs were delivered from 1983-1991, but as each leaves service it means fewer such boats for the RN to rely upon – as it stands there are just five currently in service with not all available for operations.

HMS Triumph, seen here with the Type 45 destroyer, HMS Daring. When Triumph retires it will be the end of an era for a successful class of SSN. (Photo: UK MoD/Crown Copyright) 

Astute ClassTrafalgar Class
TitleAstute ClassTrafalgar Class
SubcategoriesSubmarines: nuclear, attackSubmarines: nuclear, attack
SuppliersBAE SystemsBAE Systems
Manufacturer CountryUKUK
Total Ordered77
Total Delivered57
Unit Cost (US$)2000000000.00300000000.00
First Delivery Date20101998
Out Of Service DateU2021
StatusIn productionOut of production
Entry URL
Length 1 (overall)97m85.4m
Width 1 (overall)11.3m9.8m
Depth 2 (draft)10m9.5m
Weight 1 (overall)7,200t5,298t
Speed 1 (maximum)30kt30kt
Depth 1 (overall)300m300m

This data has been verified by the same team that brings you Defence Insight. Want to learn more?

With a limited number of SSNs ready for tasking it puts at risk the UK’s commitment to provide a boat for the Submarine Rotational Force – West (SRF-West) based out of Australia. 

As part of the AUKUS arrangement to help Australia develop a SSN capability, the RN is scheduled to station one of the Astute-class boats from the Royal Australian Navy base at HMAS Stirling, near Perth from 2027 and increase visits from 2026.

But AUKUS is significant for the UK as its long-term future plans to replace the Astute-class SSNs under the SSN(R) programme are now tied in with Australia. 

The new SSN-AUKUS effort will see the joint procurement of a single type for both countries’ navies and this presents significant budgetary and timeline risks. SSN-AUKUS will be built to a UK design but include US technology with deliveries to both countries expected from the late 2030s. 

Construction of the SSNs will initially take place in the UK once it completes the Dreadnought SSBN programme and then it is expected that Australia will move production of its later examples to new facilities in Adelaide.

The Dreadnought future submarine deterrent project is well under way having entered Delivery Phase 3 (DP3) with the first of class HMS Dreadnought, expected to complete construction and begin sea trials. DP3 began in May 2022 with contracts awarded to BAE Systems and Rolls-Royce worth over £2 billion. 

Four boats are under construction with HMS Valiant, HMS Warspite and HMS King George VI all due to follow Dreadnought into service in the 2030s and replace the existing four Vanguard-class SSBNs. It was announced in February 2023 that steel cutting had started on Warspite.

HMS Vanguard leaving RNMB Devonport after completing a refit programme that was supposed to last four years, but instead took more than seven. (Photo: UK MoD/Crown Copyright)

Dreadnought ClassVanguard Class
TitleDreadnought ClassVanguard Class
SubcategoriesSubmarines nuclear, ballistic missileSubmarines nuclear, ballistic missile
SuppliersBAE SystemsBAE Systems
Manufacturer CountryUKUK
Total Ordered44
Total DeliveredU4
Unit Cost (US$)10500000000.002000000000.00
First Delivery Date20301993
Out Of Service DateUU
StatusIn productionOut of production
Entry URL
Length 1 (overall)153.6m149.9m
Weight 1 (overall)17,200t17,500t
Width 1 (overall)U12.8m
Depth 2 (draft)U12m
Speed 1 (maximum)U25kt
Depth 1 (overall)U300m

This data has been verified by the same team that brings you Defence Insight. Want to learn more?

The ageing Vanguard-class is under some pressure to sustain the UK’s Continuous-At-Sea-Deterrent (CASD) nuclear posture providing a 24/7 response with at least one boat always on patrol because it is becoming more difficult to maintain and sustain them. 

HMS Vanguard took seven-and-a-half years to complete a Long Overhaul Period and Refuel (LOP(R)) and in November 2022 local media reported on a fire incident on HMS Victorious whilst it was on patrol forcing it to return to base.

Whilst the damage to Victorious was limited and the ability to provide CASD was reportedly not affected by this incident, both issues offer a warning that should any further problems arise then boats might not be available to carry on continuous patrols. 

Previously known as the Successor programme, the Dreadnought project took some years to get started due to political concerns in the early 2000s and then financial worries after 2010. Concept work did not begin until 2007 and only got approval as Successor in 2011. Then it was not until October 2016 that steel was cut on Dreadnought.

Looking ahead these projects are running on tight time and schedule margins that must be kept to in order to ensure that the transition from the Trafalgars to the Astutes and from the Vanguards to the Dreadnoughts are completed successfully. 

Furthermore the RN has the unprecedented challenge of combining its future SSN procurement with an ally and managing the risk on delivering a SSN-AUKUS solution for both the UK and Australia.

Shephard's DSEI 2023 coverage is sponsored by:

Tim Fish


Tim Fish

Tim Fish is a special correspondent for Shephard Media. Formerly the editor of Land Warfare …

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