Arrowhead 140 or Leander – Which would be the best Type 31e Frigate?

Two strong contenders for the Type 31e Frigate programme have emerged, let’s take a closer look at the offerings.

During a 2016 Defence Select Committee hearing, First Sea Lord Admiral Sir Philip Jones described the vessel that would become Type 31e 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 sitting between the high-end capability delivered by the Type 26 and Type 45, and the constabulary-oriented outputs to be delivered by the five planned River-class Batch 2 OPVs”.

A September 2017 graphic released by the Royal Navy (visible at the top of this article) stressed modular adaptability and flexible construction of the design for export opportunities. Core requirements of the Type 31e frigate include 76mm or larger 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. A price of £250 million per ship has been set for the first batch of five frigates, which are intended to enter RN service from 2023 to replace the five general purpose Type 23 frigates.

We will be comparing the Babcock/Team 31 offering, the Arrowhead with the BAE/Cammell Laird offering, the Leander. This is based on publicly available information.

The Basics

Arrowhead is expected to sit at 5,700 tonnes and 138.7 metres in length, the ships company is around 100 with space for an embarked military force of 60. Babcock’s Team 31 has selected the proven in-service Iver Huitfeldt frigate design as the baseline for their T31e product.

Leander is expected to be around 4,000 tonnes and 120 metres in length with a ship’s company of about 120 with space for an embarked military force of 30. The Leander design has evolved from the Khareef class corvettes built by BAE Systems.

Endurance/Speed/Range

The requirements here are pretty straightforward, the Ministry of Defence demand that “T31e shall operate globally with sustained forwward presence” and that it must have “the speed for interdiction of commercial vessels and maintaining station with adversary warships in UK waters”.

Both vessels have a broadly similar endurance, at around 30 days with the core crew embarked.

Arrowhead:

• Speed of 28 plus knots
• Range of 9000 nautical miles at 12 knots

Leander:

• Speed of 25 knots maximum
• Range of 8100 nautical miles at 12 knots

Armament/Weapons Capabilities

Arrowhead features Medium Calibre Gun options up to 5” (127mm) for maritime interdiction, self-protection and engagement of surface and land targets. Small Calibre Guns up to 40mm calibre can be located in predesignated upper-deck weapon positions.

Additional capability options include:

• Provision for up to 8 canister-launched SSGW
• Up to 32 Vertical Launch cells, capable of hosting SAM/SSGW/Land Strike/ASW ordnance.
• Installation of Close-In Weapons Systems, such as Phalanx.
• Towed array sonar

Babcock say that the ability to fit the existing systems and equipment from the parent design, the Iver Huitfeldt class frigate, is retained to provide flexibility in the capability supplied at build and through the life of the platform. The company say that, for example, this retained capability means that (just like on the base design) a 32 cell Mk41 Strike Length silo can be fitted to incorporate a combination of a larger number of anti-air missiles, vertical launch anti-surface missiles, precision land attack missiles or ASW weapons such as ASROC. This particular adaptability feature they say, alongside the ability to install a 127mm medium calibre gun, host an organic helicopter such as Merlin, install sensors such as a towed array/variable depth sonar and re-introduce a magazine-launched torpedo system, amongst other proven features, will allow the platform to be tailored on build and through-life to suit operational requirements from low-threat maritime security to task group operations.

With Leander, things aren’t all too different. The design features a Main Gun – 57mm to 127mm, two Small Calibre Guns – 20mm to 40mm, Mini Guns, Heavy Machine Guns and General Purpose Machine Gun mounts. Additional options with this design however while similar, are fewer in overall numbers.

• 12+ CAMM missile launchers
• Installation of Close-In Weapons Systems, such as Phalanx.
• A strike length Vertical Launch System can be fitted midships to fire a mixed load of AAW, ASuW, ASW and land attack missiles)
• Hull mounted sonar and twin towed array sonar

Realistically, no one’s expecting a high end surface combatant and that’s largely the whole point of the Type 31e programme, however, the armament of both vessels really just depends on the money to pay for it as both designs aren’t short of the options to fit the systems. The builders can tout a huge array of offerings, the important point to consider is paying for those options. That being said, Arrowhead would appear to be the most capable warship as it has the larger amount of space to potentially fit systems.

Mission Bays and Boat Bays

Arrowhead features 4 large dedicated Boat Bays
with flexible launch & recovery arrangement to cater for varying
operational roles, including the deployment of RHIBs, USVs & UUVs. The Mission Space which is located under the flight deck, say Babcock, offers significant operational flexibility allows for numerous TEU (Twenty Foot Equivalent Unit) containers, extended stores, or personnel accommodation space.

Leander features a mission space capable of hosting a maximum of 8 ISO Containers with HADR and Special Forces options. BAE also say that the access hatch features an ISO capable crane rated at 4t. Combinations of the following are feasible:

• 4 x Boats
• 8 x ISO containers

The Type 31e requirement doesn’t mention a mission bay only ability to carry two TEUs, both vessels appear to more than meet this requirement however Leander appears to have edged ahead here.

Aviation Capabilities

Arrowhead’s flight deck can land a Merlin sized helicopter and the vessels hangar will be capable of storing one or if required, according to Babcock, two Wildcat helicopters together.

Leander’s flight deck appears to be able to land a Merlin sized helicopter but it appears that the hangar would not be able to host one, being stuck with a Wildcat up to Seahawk sized helicopter.

Build Programme

For Arrowhead, the distributed build and assembly approach would see work going to Appledore in North Devon, Ferguson Marine on the Clyde, Harland and Wolff in Belfast with integration in Rosyth. Babcock say that the Arrowhead design lends itself equally to either a single build strategy, or a cross–site build strategy bringing together modules – an approach used for aircraft carrier assembly at Rosyth.

For Leander, BAE Systems will partner with Cammell Laird, who would ‘Prime, build and assemble’ the vessels at their Merseyside facility while the Clyde will focus on the Type 26 Frigates. Cammell Laird would be main contractor with BAE providing design and combat systems.

Verdict

Leander is smaller and may be less expensive, the platform will utilise systems already in use around the fleet lowering any extra costs associated with new and specialist technologies. However being the smallest of the two, the room for future growth and adaptability may be less than desired, potentially impact any future exports over the decades.

On paper, it would appear that the Arrowhead design is the most capable, but the downside of that could be the cost. Can this design be built in numbers for a maximum price of £250 million? The main downside as far as I can see with Arrowhead is the use of a new radar type and a new Combat Management System at a time when the Royal Navy is moving towards fleet standardisation. Going in another direction would add cost and complexity.

In summary I believe the Arrowhead 140 design to be the better option for the Type 31e Frigate, the option most inline with the requirements set out by the Ministry of Defence and the option most in line with the National Shipbuilding Strategy, but only if the costs are kept under control.