Type 31 frigate

The Type 31 frigate, also known as the Inspiration class, and formerly known as the Type 31e frigate or General Purpose Frigate (GPF), is a class of five frigates being built for the United Kingdom's Royal Navy, with variants also being built for the Indonesian and Polish navies. The Type 31 is intended to enter service in the 2020s alongside the eight submarine-hunting Type 26 frigate and will replace the five general-purpose Type 23 frigates. The Type 31 is part of the British government's "National Shipbuilding Strategy".

Under construction by Babcock International, it is based on the Odense Maritime Technology (OMT) frigate hull and is marketed under the name Arrowhead 140. The design has been sold to Indonesia as the two ship '' Fregat Merah Putih'' ("Red-White frigate") in September 2021, and to Poland for the three ship ''Wicher''-class frigates in March 2022''.''

Development

The 2010 Strategic Defence and Security Review (SDSR) authorised the Global Combat Ship (GCS) programme, which would replace the Royal Navy's thirteen Type 23 frigates. Earlier that year, BAE Systems was awarded a four-year, £127 million contract by the Ministry of Defence (MoD) to design the new class. It was planned that two variants of the class would be built: five general purpose frigates and eight anti-submarine warfare frigates. There was to be little difference between the two variants, except for the Sonar 2087. Initial expectations were that construction would start in 2016 and the ships would gradually replace the Type 23 frigates by the mid-2030s. The 2015 Defence Review decided that only the eight anti-submarine warfare Type 26 frigates would be ordered and five general purpose frigates to an altogether different design would be ordered to give at least 13 frigates in RN service.

General Purpose Frigate

The resultant General Purpose Frigate (GPFF) was to be a lighter, flexible and more affordable general purpose frigate class. According to the 2015 SDSR, the lower cost of these frigates could lead to the Royal Navy acquiring more than five, therefore increasing its overall numbers of frigates and destroyers. During a defence and security lecture in July 2016, GPFF was referred to as the Type 31 frigate by the First Sea Lord, Admiral Sir Philip Jones, who also stated that Type 31 frigates could permanently operate " East of Suez"—from the Persian Gulf region to the Asia-Pacific. During the same month, BAE Systems revealed two general purpose frigate designs: the "Avenger class", which was based on the " ''Amazonas''-class/River-class Batch 2 offshore patrol vessel", and the "Cutlass class" that was described as a "significantly stretched and enhanced derivation of the ''Al Shamikh''-class corvette design". ''The Sunday Times'' stated that Babcock International and BMT had also submitted one design each. Jones described the GPFF as "to be a much less high-end ship. It is still a complex warship, and it is still able to protect and defend and to exert influence around the world, but it is deliberately shaped with lessons from wider industry and off-the-shelf technology to make it... more appealing to operate at a slightly lower end of Royal Navy operations." IHS Janes described it as a "credible frigate" that will cover "maritime security, maritime counter-terrorism and counter-piracy operations, escort duties, and naval fire support... ittingbetween the high-end capability delivered by the Type 26 and Type 45, and the constabulary-oriented outputs to be delivered by the five River-class Batch 2 OPVs."

A September 2017 graphic released by the Royal Navy stressed modular adaptability and flexible construction of the design for export opportunities. Core requirements of the Type 31e frigate included a medium calibre gun, point defence systems, hangar and a flight deck for Wildcat or ten tonne helicopter operated by a crew of around 100 with space for 40 more personnel. The British government released a Request for information (RFI) in September 2017, detailing the desired characteristics of the Type 31e. The RFI provided greater details such as a "Medium Calibre Gun" of greater than , a point defence anti-air missile system and the optional ability to launch and recover unmanned aerial vehicles.

National Shipbuilding Strategy

In October 2017, the ''Financial Times'' stated that "officials inside the Ministry of Defence, the Treasury and Royal Navy have long resented the obligation, set a decade ago, to maintain skills and shipbuilding capacity at BAE's shipyards on the Clyde regardless of naval needs. It quoted Francis Tusa, a defence analyst, who argued that the competition appeared to be designed to break BAE's hold on naval shipbuilding; "were they to have bid as BAE Systems, they wouldn't win. That is absolutely obvious. The fact is that the Type 31 is slanted probably to exclude any bid that includes BAE." However, this was denied by the MoD, which stated that the competition was designed to improve speed of delivery and reduce cost.

In order to maintain national shipbuilding capacity, the 2017 national shipbuilding strategy proposed ordering an initial batch of five Type 31e frigates with an initial in-service date in 2023, with their cost limited to a maximum of £250m each, to be followed by a second batch order of Type 31 for the Royal Navy.

The refresh to the National Shipbuilding Strategy published by the UK Government in March 2022 stated: Type 31, the pathfinder project of the 2017 strategy, got to contract on schedule and for the headline price demanded, with the capability exceeding many expectations.

Design tenders

Throughout 2017, several designs from different companies were suggested as contenders for the Type 31. BAE submitted two designs, "Avenger", essentially an improved Batch 3 River-class OPV, and "Cutlass", a significantly stretched and enhanced derivation of the ''Al Shamikh''-class corvette. BMT submitted a design called "Venator 110", with Steller Systems putting forward project "Spartan", and Babcock offered a design named "Arrowhead 120".

In October 2017, BAE Systems announced that it would withdraw from the Type 31e competition as a main contractor, citing the capacity constraints of its shipyards on the Clyde, which were full with the work on the new River-class patrol vessels and Type 26 frigates. Instead, BAE announced a partnership with Cammell Laird, whereby BAE would provide its expertise in design and systems integration, while Cammell Laird would be the prime contractor and be responsible for the assembly of the ships at its yard at Birkenhead. The planned design was named "Leander", a reference to three previous classes of ship in the Royal Navy.

In November 2017, it was announced that BMT and Babcock signed a co-operation agreement for the Type 31. They did not choose between their respective "Venator 110" or "Arrowhead 120" designs, but instead would explore their designs to determine the best possible option. In late May 2018, Babcock, partnered with BMT, and Thales Group announced the "Arrowhead 140" design, based on the hull of the Danish s.

The competition was suspended on 20 July 2018 due to 'insufficient compliant bids' being received; however, ''The Times'' claimed this was due to a "funding crisis". The competition was restarted in August 2018.

Competitive design phase selection

On 10 December 2018, three groups were selected for the competitive design phase:
* BAE Systems/Cammell Laird with their planned Leander design
* Babcock/BMT/Thales with their Arrowhead 140 design (AH140)
* Atlas Elektronik UK/ ThyssenKrupp Marine Systems, which was likely to be based on the MEKO A-200 design

Both the BAE Systems and Babcock led entrants had already been put forward when the competition was temporarily suspended. The third bid was submitted by the Atlas Elektronik UK-led team. Both the Babcock and Atlas proposals included Ferguson Marine on the Clyde and Harland & Wolff in Belfast. By August 2019, both of these companies announced that they were in financial difficulties.

It was announced on 12 September 2019 that the Arrowhead 140 design had been selected as the base design for the Type 31 frigate. A contract was formally awarded to Babcock on 15 November 2019, for an average production cost of £250 million per ship and an overall programme cost set to be £2 billion with £1.25 billion value to Babcock.

On 20 January 2020, the Public Accounts Committee was informed by the Permanent Secretary for Defence that the first ship will be launched by 2023, but the in-service date will be in 2027. Earlier statements had been for an in-service date would be in 2023. In September 2022, John Howie, chief corporate affairs officer for Babcock International, stated that all five ships would be "delivered" to the Navy by 2028, though other sources suggested that the actual "in service" date might be somewhat later.

Arrowhead 140

The AH140 design submitted by Babcock, BMT, and Thales is a development of the s in service with the Royal Danish Navy.

The Type 31 frigate, developed from Babcock’s Arrowhead-140 design and based on the Royal Danish Navy’s Iver Huitfeldt class, is not a direct copy but a significantly reworked platform. It has been extensively redesigned to comply with modern standards, including Lloyd’s Register Naval Ship Rules, NATO’s ANEP-77 Naval Ship Code, and a broad range of UK defence requirements such as DefStan 02-900. This redesign delivers enhanced survivability, system redundancy, and resilience compared to older Royal Navy escort ships like the Type 23 and Type 45, which were built to earlier generations of standards.
* General Purpose – default option (Type 31).
* Anti-air warfare – Leverages the existing anti-air capabilities of the parent design through use of an additional long range radar such as the SMART/L or S1850M enabling wide area air defence and ballistic missile defence (BMD).
* Anti-submarine warfare – additional acoustic reduction measures such as the rafting of machinery spaces as well as provisions for a towed array sonar to the stern.
* Mine countermeasure / amphibious warfare / Multi-Mission platform – In 2023 Babcock revealed their Multi-Role Naval Platform (A140 MNP), a variant of the AH140 with mission modularity in mind and likely as a contending design for the Royal Navy's Type 32 frigate program. The design features a stern boat ramp connected to the existing mission bay under the flight deck, a side hydraulic ramp, an enlarged hangar with capacity for up to 2x AugustaWestland Merlin AW101 sized helicopters, directly connected to a full-width mission bay replacing the 32-cell VLS complex amidships capable of supporting up to three 11-metre craft (e.g. unmanned surface vehicles, rigid inflatable boats) or containers. The design is also compatible with SH Defence's CUBE system for the embarkation and movement of container stores on board.

AH140 also features a wide degree of flexibility in the component systems. It is capable of being fitted with a variety of radar masts (fixed or rotating), up to four boat bays for RHIBs or small USVs and the customer's choice of medium and small calibre gun options (up-to 127 mm in position A and up-to 76 mm in position B). Additionally, there are several options for vertical launching systems (VLS) available; from a 24-cell CAMM 'mushroom farm' configuration as cost and weight saving option, up to a 32-cell strike length Mark 41 vertical launch system for long range surface-to-air missiles (SAMs) or surface-to-surface missiles (SSMs) that can be positioned amidships. An additional 16-cell Mark 41 complex can be positioned forward of the bridge by removing the gun mount from Position B enabling either a 48-cell loadout or to free up the central sections for other facilities such as a full-width mission bay. Previous renderings of the Red-White frigate design for Indonesia have also shown an additional 56 cells of an indeterminant type and length added to the rear of the main gun suggesting that even greater level weapon customisation is available in the design.

Another major characteristic of the AH140 is that it has dedicated accommodation for more than 180 personnel but only requires a crew of less than 100, allowing for both lower sustainment costs but also for a large number of mission specific personnel such as flight crew, remote system operators, marines / special forces to be embarked, or refugees in the case of humanitarian operations.

Exports

On 16 September 2021, Babcock announced that it had signed an agreement with PT PAL Indonesia allowing it to design two AH140 derivatives for the Indonesian Navy. The class are known locally as ''Fregat Merah Putih'' ("Red-White Frigate"). The first Red White frigate had its steel cut on 9 December 2022.

On 4 March 2022, Babcock announced that it won the frigate competition for the Polish Navy. The Polish Armaments Agency selected Babcock's AH140 from three different platform design proposals provided by the PGZ-Miecznik consortium ("''miecznik''" is Polish for "swordfish"). In August 2023, the construction of the first in a series of three Project 106 frigates began at PGZ Stocznia Wojenna.

Following suggestions that the Royal Australian Navy (RAN) might adopt a "two-tier" surface combatant mix pairing the tier one ''Hobart''-class destroyers and ''Hunter''-class frigates with a smaller, less capable, but cheaper class for the RAN, Babcock Australasia reportedly offered the Arrowhead 140 to meet this possible requirement. However, the AH140 design was subsequently not selected as a candidate for the project after it was officially announced by the Australian government.

In October 2023, Babcock formally began building its bid for the Royal New Zealand Navy (RNZN) and started looking for New Zealand-based small medium enterprises (SMEs) to develop a domestic supply chain.

Characteristics

Royal Navy – Type 31 (Inspiration class)

The Inspiration class will have a length of , a beam of and a displacement of . It will have a crew complement of about 110 sailors (with available accommodation for about 80 additional personnel), a total range of 7500 nmi, and a top speed of 26+ knots.

The procurement of the equipment fit for the Type 31 differs greatly from traditional practices, with design decisions being made by the prime contractor abcockor mission systems integrator halesacting as the design authority rather than the Defence Equipment and Support (DE&S) organisation or Royal Navy personnel, in accordance to key characteristics laid down by the MoD for a general purpose frigate. The published Babcock engineering paper states: "The various rule sets and standards used worldwide to design ships deliver varying levels of capability into a warship, even amongst NATO navies. The RN’s requirements have been honed by real-world and hard-won naval combat experience in the missile age; driving some of the most exacting standards to which a warship can be designed. The Type 31 Frigate now complies with these requirements and latest standards, materially increasing its performance over many overseas Frigate designs and the legacy 1980s-designed Type 23 General Purpose Frigate that it will replace in RN service."''''

On 1 October 2020, BAE Systems Bofors announced it was under contract to supply five Bofors 57 mm Mk3 medium calibre guns and ten Bofors 40 mm Mk4 small calibre guns to the Royal Navy for the first five Type 31 frigates. The 57 mm Mk3 will equip the A position whilst two 40 mm Mk4s will be mounted in positions B and Y in a broadside configuration. In November 2022 the MoD placed a contract with BAE Systems Bofors training facilities for the 57 mm Mk3 an
40mm Mk4
naval gun systems that will be supplied with the five Type 31 General Purpose Frigates

In 2019, Forces News reported that the design would have Sea Ceptor (CAMM) missiles, an advanced air and surface surveillance and target indication radar such as the Thales NS110 and be able to operate either an AgustaWestland Wildcat HMA2 or an AgustaWestland Merlin HM2. Type 31 will have the first 4D Dual-Axis, Multi-Beam, Active Electronically Scanned Array (AESA) Radar to be fitted to a RN Frigate hales NS110

The vertical launching system for the Type 31 and its associated missile loadout has gone through a number of revisions over the course of its development. Originally, the design would retain, but would however be "fitted-for-but-not-with" its 32-cell strike length Mark 41 Vertical Launching System and in its place was to be a Sea Ceptor 24-cell ' mushroom farm' in a similar configuration as found on the Type 23 frigates. This was later revised with a more modular version of the launcher consisting of two 2x3-cell launch modules with a reduction from 24 to 12 missiles possibly as a cost-saving venture. On 17 May 2023, the First Sea Lord Ben Key stated that Type 31 frigates would in fact be fitted with the 32-cell Mark 41 Strike-Length complex. The exact missile mix for the Type 31 with the Mark-41 has yet to be confirmed but will likely eventually consist of at least 32x Sea Ceptor missiles quad-packed into one of the four 8-cell launch modules in addition to possibly integrating the forthcoming surface launched variant(s) of the Future Cruise/Anti-Ship Weapon(s) being developed jointly by the UK, France, and Italy for surface warfare capability. Other sources have previously suggested that the ship might incorporate the canister-launched Naval Strike Missiles which could be migrated over from the retiring Type 23 frigates and be fitted on the Type 31. In early 2024, it was reported that the Mark 41 system would not be integrated into the first Type 31 frigates and instead only be added during future future capability insertion periods. Indeed, as of early 2025 the Mark 41 system was not yet funded and, if it went ahead, there was no information yet on numbers of missiles or cell packing arrangements for Sea Ceptor.

In June 2023, the completed bow stem of the lead unit, HMS ''Venturer'', revealed that a bow-mounted sonar will also not be part of the initial build of the ship.

On 26 March 2024, it was announced that Sea Gnat fixed decoy launching system would be replaced across the entire Royal Navy's escort fleet with SEA's Ancilia trainable decoy launcher including on the Type 31 following a £135 million contract. A pair of launchers will be mounted to the deck and will each provide twelve ready rounds of Infrared seduction decoys and radio frequency distraction decoys to defeat missile threats and possibly the ability to launch Martlet missiles in the future.

On 14 May 2024, First Sea Lord Ben Key announced that the Type 31 frigate would be equipped with land strike capabilities. The three missiles under consideration are the Naval Strike Missile, Tomahawk cruise missile and the Future Cruise/Anti-Ship Weapon.

In June 2024, Babcock International published a technical paper outlining the development of the crewing model for the Royal Navy’s Type 31 frigate. The aim was to minimise crew size while ensuring effective operation of a large surface combatant. The resulting crew complement reflects the smallest practical and sustainable ship’s company for a 7,000-tonne general-purpose frigate capable of global combat operations, enabled by mature, high-readiness technologies and aligned with the latest naval rules and design standards.

Indonesian Navy – ''Fregat Merah Putih''

On 9 December 2022, Indonesian state-own shipyard PT PAL Indonesia held the first steel cut ceremony for the first ''Fregat Merah Putih'' (Red White Frigate) at their shipyard in Surabaya. The first frigate was laid down on 25 August 2023. The first steel cut of the second Red White frigate was made on 5 June 2024.

The second ship was laid down on 15 November 2024, five months earlier from the planned date of March 2025.

As part of the main contract, the Red White Frigate is to be armed with one OTO Melara 76 mm, one 35 mm Rheinmetall Oerlikon Millennium Gun, and two 12.7 mm Leonardo Lionfish RCWS, while the electronics and sensors includes Aselsan Mete Han AESA multi-function radar, Aselsan MAR-D / CENK-200-N air and surface surveillance and helicopter control radar, Aselsan FERSAH hull-mounted sonar, Aselsan Target Designation Sight, HAVELSAN ADVENT combat management system, HAVELSAN-made combat information center equipment, two 8x6 130 mm Aselsan KARTACA-N decoy launching systems, IFF system from Leonardo, and Elettronica electronic warfare suite.

Additional equipment in "fitted for-but not with" configuration includes additional single OTO Melara 76 mm gun, additional two 12.7 mm Leonardo Lionfish RCWS, 8x8 cells (total 64 cells) Roketsan MİDLAS vertical launching system (VLS) for surface-to-surface and surface-to-air missiles, two Leonardo B515/3 triple 324mm torpedo launchers for MU90 LWT torpedoes, and Aselsan CENK 400-N AESA long-range air and surface surveillance radar.

Polish Navy – ''Wicher'' class

On 16 August 2023, a steel-cutting ceremony took place for the first of the ''Wicher''-class frigates, ORP ''Wicher''. The ceremony was held at PGZ Stocznia Wojenna in Gdynia.

Also on 16 August 2023, it was announced that PGZ and Babcock signed an agreement including an option to build five more units. If exercised, this would result in at total of eight ''Wicher''-class vessels being procured by Poland.

At the MSPO 2024 defense expo, it was announced that the ''Wicher''-class frigates will be fitted with Kongsberg's NSM anti-ship missiles instead of Saab's RBS 15 Mk 3.

On 9 May 2025, Polish shipbuilder PGZ cut the first steel to be used in the construction of the second Miecznik-class frigate ordered by the Polish Navy.

Ships of the class

The Royal Navy's five ships will be known as the "Inspiration class". In May 2021, the names of the five Type 31 ships were announced by the First Sea Lord; these were selected to represent key themes of the future plans of the Royal Navy and Royal Marines:

*''Active'', named after the Type 21 frigate which served in the Falklands War and in support of Britain's Overseas Territories, symbolising forward deployment of ships overseas.
*''Bulldog'', named after the World War II , which escorted shipping convoys in the Atlantic, was chosen to represent operations in the North Atlantic. ''Bulldog'' captured the and its top-secret Enigma machine.
*''Formidable'', named after the World War II-era aircraft carrier , represents carrier operations. ''Formidable'' took part in the war in the Mediterranean, Atlantic and Pacific.
*''Venturer'', named after the World War II submarine , which while underwater, destroyed an enemy submarine, symbolising technology and innovation.
*''Campbeltown'', named after , which was involved in the daring St Nazaire raid was chosen to symbolise the Future Commando Force.

As of 2021, all ships were planned to be service by February 2030, though by mid-2024, that plan may have slipped by at least a few months. ''Italics'' indicate estimated date.

See also

* Future of the Royal Navy
* Type 32 Frigate
* Type 26 Frigate
* Frégate de défense et d'intervention (FDI)– equivalent French frigate
* F126 frigate
*
* (PPA)
* – Arrowhead 140 parent design

References

Bibliography

*
*Johnson, J. Howard, M (November 2022). "''Type 31 Frigate: Complex Warship Design for a Dynamic Operational Environment"'' Proceedings of International Naval Engineering Conference (INEC) 2022 doi 10.24868/10665
*Johnson, J. Howard, M (June 2024). "''From UMS to Full Autonomy; Experience from a Complex Warship Programme"'' Proceedings of RINA Warships 2024: Future Surface Combatants Conferenc


{{Type 31 frigate

Frigate classes
31
Ship classes of the Royal Navy
United Kingdom defence procurement