Shrinking fleets: UK Royal Navy woes

A rare sight at HMNB Devonport as three Type 23 frigates sit alongside at the turn of the New Year. HMS Montrose, (right) has since been decommissioned. Credit: UK MoD/Crown copyright.

The UK Royal Navy’s battle to maintain a viable fleet of surface warships able to undertake necessary taskings sustained a further, albeit planned, hit on 17 April as the Type 23 frigate HMS Montrose was decommissioned after 30 years of service. 

The step marks the second Type 23 decommissioned ahead of schedule, following the retirement of HMS Monmouth in 2021, which was planned to be retained in service until the 2026 timeframe. HMS Montrose was listed in official figures as having a planned out-of-service date (OSD) of 2027, meaning that it has had to come off the line four years ahead of schedule.

A magnifying factor of the retirement of the increasingly ageing Type 23 frigates is that the timeline for the replacement Type 31 frigates will see the first-in-class HMS Venturer enter service in 2027, by which time the fleet could be further reduced with the retirement of Type 23 frigates HMS Lancaster and Iron Duke in 2024 and 2025 respectively. 

Should these timelines remain, the UK Royal Navy’s surface fleet of major surface combatants, made up of the Type 23 frigates and Type 45 air defence destroyers, could be down to just 15 vessels. The current structure of the Royal Navy’s missions dictates a 19-strong surface warship requirement among the Type 23 and Type 45 classes. 

According to the UK’s shipbuilding programme, five Type 31 Inspiration-class general-purpose frigates will be introduced into Royal Navy service from 2027, to replace outgoing general-purpose Type 23 frigates. 

In addition, eight Type 26 frigates, currently under contract or in build, will begin to enter service between 2028 and 2035, which will replace the anti-submarine configured Type 23 vessels. On current planning, the timeline to replace the anti-submarine variants matches, meaning there should be no further reduction in Royal Navy surface combatants during this period. 

A further class of warships, dubbed the Type 32, are thought to be being developed to act as multi-purpose motherships for uncrewed mine countermeasure vessels, to replace the remaining nine crewed minehunters of the Hunt- and Sandown-classes, and as of December 2022 planned to enter service over a period of three years commencing in 2032. However, the class is still in its concept phase and timelines likely to shift in the years ahead.  

In an attempt to offset the looming drop in surface combatant numbers, the Royal Navy is sending many of the remaining Type 23 frigates into service life-extension (LIFEX) programmes. Of the Type 23s in service, HMS Argyll underwent a LIFEX programme in 2022 in a bid to keep the vessel in the fleet until the 2027-2028 timeframe.  

A table showing the planned OSD for the Type 23 frigate. Brackets indicate potential/confirmed changes. Credit: GlobalData

In a series of Freedom of Information (FoI) requests made in late-2022 to the UK Ministry of Defence regarding the timelines for the departure of the Type 23 frigates and introduction of the Type 31 and Type 26 replacements, Global Defence Technology was informed that while information did exist that outlined how the surface combatant fleet would be effected by the apparent slip in timelines, all details were being withheld up Section 26(1)(b) of the FoI Act.

Despite the accepted public interest, it was determined that providing the details of which Type 23 frigates would undergo a LIFEX programme to delay their departure from service and offset the dip in surface combatant numbers, revealing the Royal Navy’s forward planning could be exploited by adversaries. 

However, it is understood that, in line with vessel class certification rules, the out-of-service date of warships can be extended for a maximum of six years following completion of each upkeep maintenance programme. 

As UK naval bombshells go the announcement that the UK’s minimalist Type 31 frigates will be fitted with the Mk41 vertical launch system (VLS), bringing with it a potential new range of anti-surface and anti-air lethality, could take some beating. 

During a keynote speech at the Sea Power Conference in London on 17 May, the UK First Sea Lord Admiral Ben Key, stated the Type 31 frigates would receive the Mk41, sending naval watchers into overdrive while simultaneously raising questions over affordability, timelines, and reasoning for a class already well into the construction phase.

Originally designed as a light patrol frigate, the Type 31 was envisaged to feature minimal surface-to-surface attack options, primarily based around the single Mk110 57mm main gun from BAE Systems and two Mk4 40mm secondary weapon systems from Saab Bofors. Anti-air capability was to be provided by the SeaCeptor ‘mushroom farm’, amidships.

The deliberately light kinetic surface attack options, and reuse of existing equipment ported over from the outgoing Type 23 frigates, was determined as the best way to keep the costs down and ensure each of the five frigates was able to be delivered at a cost of £250m per hull.

However, in November 2022 it was announced that the UK would acquire 11 ship sets of the Naval Strike Missile (NSM) from Kongsberg, offering a canister-launched anti-ship missile that would be equipped to the in-service Type 23 and Type 45 vessels. The NSM will effectively replace the outgoing and obsolete Harpoon Block 1C.

Should the canister launched NSM be then removed from Type 23 frigates as they leave service and installed onto the Type 31, the vessel would be able to conduct the full range of anti-ship and anti-air operations, through the NSM and SepCeptor system respectively.

The announcement of the Mk41 integration raises a number of questions about the programme, which, although the design allows for the installation of the VLS, has been previously finalised to include just the SeaCeptor air-defence capability.

Were the Type 31 to get the NSM sets, what purpose would there be for the installation of the Mk41 VLS? Turning the question around, should the Type 31 frigates not receive the NSM, would the missiles instead be fitted to some or all of the eight Type 26 anti-submarine warfare frigates under construction, which will also feature the Mk41 VSL?

A final, for now, question emerges regarding the prospect that the SeaCeptor air defence system is integrated into the Mk41, instead of the traditional mushroom farm arrangement as seen on the Type 23 frigates and Type 45 air defence destroyers.

These factors could in turn influence the cost of build, at a time when manufacturer Babcock is in dispute with the UK Ministry of Defence over the profitability of the Type 31 programme. 

The answers to these questions will likely emerge from a new assessment phase being undertaken by UK stakeholders in the Type 31 programme and the US Navy to determine how the Mk41 could be integrated into the frigate and the potential financial implications.

Speaking to Global Defence Technology in May, a Royal Navy spokesperson said: “The Mk41 vertical launching system will deliver surface launched strike operations against a full spectrum of targets. Working closely with the US Navy, we have commenced an assessment phase to explore the options and costs associated with fitting [Type] 31 with Mk41. It is too early to provide any further information whilst this commercially sensitive work is ongoing.” 

In looking to fit the Mk41, the UK could offer a degree of standardisation across its surface combatant fleet with the eight Type 26 anti-submarine warfare frigates also to be fitted with the system. 

The Type 45 air defence destroyers could then become an outlier in RN service, as they already feature the 48-cell Sylver VLS for the Aster 15 and Aster 30 missiles, which will be augmented by a further 24-cell SeaCeptor farm. However, the replacement Type 83 class, due to enter service in the late 2030s, could change to the Mk41 or its future derivations. 

In doing so, the UK will fall into commonality with the US and many Nato allies already using the Mk41 system, potentially offering the use of a variety of current and future anti-air, anti-surface, ballistic missile defence and strike missiles, including the RN’s Future Offensive Surface Weapon.

James Marques, aerospace and defence analyst at GlobalData, said that the UK admiralty had “long complained” that the RN’s surface fleet was “capable in defence”, but lacked offensives options. The lessons being learned from the ongoing war in Ukraine, and how quickly stocks of expensive high-end missiles can be used up in war, was another factor.

“Harpoon is ageing and was hastily fitted to some Type 45s last year only after Ukraine. I think the appetite to satisfy the Royal Navy's shopping list has grown massively in 2022, and they are aiming for a force that can credibly move firepower to both the Indo-Pacific and Europe/Nato,” Marques said.

The story of a class of warships, cheap to design, build, and enter into service, thus avoiding the expensive complexity of a larger Type 26 acquisition, still has come chapters left to write. 

The Royal Navy’s surface combatant fleet is a force in need of renewal, and the replacement of a single class (the Type 23) with two types of frigates (the Type 26 and Type 31) offer the most expedient way to replace older vessels as they are removed from service.

However, challenges remain in the timeline to ensure that new frigates are able to enter service as planned, with the fleet already set to dip in the middle of this decade. Should the Type 26 and Type 31 programmes move to the right, this reduced fleet of surface combatants, at a time when maritime security requirements are increasingly critical, could drop even further.

Though it should be recognised that while a future Royal Navy surface combatant fleet of Type 26 anti-submarine warfare frigates and Type 31 multi-role platforms offers much-improved capabilities compared to the legacy Type 23 class, the near-term dip in hull numbers will be keenly felt, and noticed, just as Nato’s own continental force assessment plans are being finalised.