The recent activity surrounding the Type 31 programme has again brought to the fore the long running debate about what it should be, as well as reinvigorate the debate about what frigates are, why we ‘need’ them, and how we increase our hull numbers at the expense, perhaps, of some of the ‘gold plating’ we Brits are so fond of. I have wanted for some time to try and draw together the key issues that define both the platform and the requirement, and in addition want to put my own spin on the Type 31 and what it should look like. I’ve been tinkering with this for some time, but since the subject is a perennial favourite it has not been screaming at me to be published.

Spoiler alert. In a past guest post on Think Defence on a similar subject, my biggest criticism was that I decided that I wanted to have frigates, and then wrote a post about how frigates were essential. I haven’t changed my conviction and the conclusion I’m going to draw is that we need frigates. But then, the frigate (or at least the principle of one) has existed for a very long time and its relevance is unchanged today; I hope to explain my take on this in a way that makes sense.

The need for lighter ships

The general pattern of naval warfare since time immemorial has been for a two-tier force – a heavy core of ships designed for battle, and a lighter force that finds the enemy and guides in the heavies. That is, of course, assuming you have some sort of power-projection ambition and are not simply interested in defending your little patch of coastline. The smaller ships generally patrol, escort and carry out a variety of other tasks that the heavies would not normally be expected to do. The defining factor that I associate with the frigate is that of endurance, a ship generally operating alone and on orders, providing sovereign representation around the world backed up by a moderate amount of force. It has long been accepted that this form of global presence bears fruit in defence engagement, itself a tool of foreign policy, and has a disproportionate effect diplomatically. In addition, our adversaries, competitors and allies all have military capabilities in areas that interest us or upon which we depend – the Mediterranean, the Levant, the Arabian/Persian Gulf, etc. Maritime power, freed from the constraints of land basing, overflight and access, has reach and persistence across a significant proportion of the world’s populated landmass, the littoral, and a great deal of influence can be exerted from the sea.

This we all know, and few can sensibly challenge this position – moreover I do not intend to waste time trawling through the counter-arguments and challenges. Maritime power has its place, and that’s the basis on which I am building this discussion. Dissenters click here.

Defining the Frigate

The heavy battle forces of a two-tier navy are hugely varied, ranging from battleships to aircraft carriers, specialist destroyers and cruisers. The common theme, however, is that they are optimised to work together as a force – carriers providing long range striking power as did the battleships of old, cruisers and destroyers protecting the core, specialist amphibious shipping and the logistics chain of naval auxiliaries. They can often political vanity projects, floating arsenals that make military statements rather than fulfilling a natural purpose within a balance task force. In this I think the USN has had the balance right for the longest time, and has only recently fallen off the sensible boat with the Zumwalt destroyer.

The frigate is much harder to define, in fact it is near impossible with the range of ship types available today. Take the Horizon class – the French and Italians define their hulls as frigates, whereas the UK equivalent (the Type 45) is defined as a destroyer. Both classes undertake independent operations as the frigates of old did, but both were designed as task force AAW escorts with virtually the same weapons and sensor fits. The US Oliver Hazard Perry class was a great example of a frigate designed for AAW and ASuW, but such units were regarded more as Cold War convoy escorts and were eclipsed by the larger destroyers (such as the Arleigh Burke, a destroyer which many navies would call a cruiser). The escort role, however, remains a valid characteristic I associate with frigates.

It may also be sensible to associate certain roles to frigates, and we have an illustrious history stemming from the Second World War that identifies frigates as antisubmarine warfare specialists. The Russians, however, firmly screw up that idea with their anti-submarine warfare destroyers (the Krivaks and Udaloys) and the US has always likewise invested in their destroyer classes (the Spruances and, again, the Arleigh Burkes). In fact this rather suggests that the frigate is a platform of choice for smaller navies, and is really rather European in nature.

At the smaller end of the spectrum, corvettes continue to grow in size and capability, muddying the waters further when it comes to definitions. There are a number of small but highly capable platforms out there (at least, they appear capable on Wikipedia!) that seem to offer frigate-like capabilities. However, the distinction between frigates and corvettes is, I think, much easier – range and endurance. Smaller ships means smaller crews, smaller fuel tanks and smaller fridges. Smaller hulls are less able to stand up to heavy weather or provide stability for weapons systems. A corvette might pack a heavier punch than a frigate, but I define a frigate, at least in part, by the ability to deploy for sustained periods and is not necessarily a step-change in capability over a corvette.

Sloops – don’t. Just don’t. Sloop fans click here.

Simple vs Complex, Little vs. Large

One of the discussion topics that arises when fantasising about future fleets is the idea of a large vessel with considerable spare capacity, such as a Bay class LSD(A). These platforms are generally simpler to design, and that has value when you consider that steel remains cheap and air is still free. The range of merchant designs available that could be adapted into future warships is dizzying, and again represents highly attractive options for conversion or adaptation.

If the benefits of large ships are so evident, then why build smaller ships at all? After all, smaller ships generally attract higher design costs as you squeeze systems into smaller spaces, and often require bespoke ancillary equipment to optimise available space and power requirements. Squeezing weapons systems into the equation raises the cost further.

However, smaller ships have considerable advantages as high-end combatants, which is, after all, their intended purpose. Smaller size generally invites a higher power-to-weight ratio, especially when you consider power sources such as gas turbines which are compact and responsive; it also makes it considerably easier to design a platform that is maneuverable. Smaller ships are also less visible – their lower profile makes them much more difficult to identify visually, they also have smaller radar signatures and are more easily designed to be stealthy. The design work that has to go into a smaller platform also makes it easier to achieve signature reductions such as noise or IR, both characteristics that are increasingly important in effective operations.

This is the difference between simple warships and complex ones. OCEAN, a large, flexible and capable unit, is a great example of a simple warship. A Type 26 frigate is most definitely a complex one. However, it is difficult to fit any further definitions in between these two extremes because your cost-benefit analysis rapidly tips down the slope as soon as you add complexity to a simple warship, or attempt to simplify a complex one. Imagine trying to achieve acoustic quietening on a converted rig support vessel, or the cost of making something the size of OCEAN drive at 28kts. It is not impossible, but when you are minding your figures you have to determine your accepted measure of complexity, else your money will disappear into the design process for little gain. Of course, this assumes that you know what you want in the first place, and that your shipbuilding programme is not just a political statement for the sole benefit of employment.

Jack of All Trades or Master of One?

So, as we continue drowning in mud trying to find the elusive definition of a frigate, it is important to make at least one further assumption – what we want is a warship. A frigate is not a one-hull amphibious invasion machine, or an air defence ninja; it is a small platform and, given the inevitable cost constraints that lie with it, it cannot be everything. It will never be as capable as an Arleigh Burke for the cost of a Nissan Micra, and so we have to be critical about what we expect this thing to actually do. Nevertheless, I think any truly effective warship has to be able to do one thing, and that is survive.

Survival is everything. If a frigate cannot deal with an isolated attack, it cannot serve its function as an outlier of the main fleet. Moreover, if it cannot defend itself it appears weak or (possibly) useless, either inviting attack in a high-intensity scenario, or (worse) having no credibility when it conducts the defence engagement tasks we expect it to carry out independently. What you define as the ability to survive is variable, but something as basic as Phalanx is probably not enough; a decent point-defence missile system is, in my view, the requisite minimum when you consider the complexity of modern missile systems.

On top of survival we have to add at least one capability that makes the frigate a platform that will be noticed. The RFAs and survey platforms we deploy are able to operate relatively unnoticed in the wider diplomatic vision, but a single frigate to the Far East generated considerable interest which is precisely the reason why we sent it as opposed to an RFA. Irrespective of the fact that a concerted attack by the PLAAF and PLAN could wipe it out in minutes, it’s not expected to operate in that environment. It will, however, draw attention when it sails through Chinese claimed waters in the South China Sea on a ‘freedom of navigation’ exercise. If we were expecting an attack, we’d be sending a task force and it wouldn’t be alone. It’s perfectly possible for the ‘noticeable’ capability to be the ship’s own self defence capabilities; Radar 997 and Sea Ceptor are meant to be pretty effective, far more so than something tiny like the RAM system or a single Phalanx. The Russians and Indians have got this, which is why their newer platforms sport a fairly impressive missile system with Klub, Oniks and Brahmos (even if they couldn’t do much else). The Type 23 delivered this with its ASW ability, and ASW remains a specialist capability that the RN is still master of.

A note on helicopters. A hangar and an aircraft is a great enabler, but as a weapons system it is hugely limited by crew endurance and maintenance. Even at the height of wartime with every rule thrown out of the window, you cannot have 24/7 availability from one aircraft. So as useful as they are, a helicopter is not a capability all of its own. Something with greater endurance, such as ScanEagle, has equal potential without the costs associated with a helicopter.

Where frigates go wrong

I think the Type 26 is a good example of a frigate gone wrong. There, I said it!

However, after much tinkering I’ve decided that’s a subject for another post altogether.

So what is a frigate?

I should probably draw some sort of conclusion here.

The Type 31 frigate project is one of the most interesting and exciting defence procurement challenges we have seen for a long time. It is potentially revolutionary in delivering small, agile warships that meet the Royal Navy’s minimum baseline for a globally deployable combatant.

A recent article by the UK Defence Journal regarding the Type 31 frigate project has inspired me to put my own thoughts to paper as an interested observer of naval development. Although well-written, I feel strongly that it missed the point and makes too much of comparing the Type 31 to the Type 26, almost as if Type 31 is a cheaper alternative to the larger warship. I am naturally an optimistic individual and want to bring out the opportunity that Type 31 affords the Royal Navy of the future. This article is exclusively based upon open source reporting and makes assumptions that are precisely that – assumptions. As with any written word regarding the military, many capabilities are not made public for good reason, so nothing here should be regarded as a statement of fact regarding the true nature of the Type 26 or Type 31 programmes.

What we know about Type 31 fills a small Post-It note, yet has inspired reams of guesswork based on lots of assumptions. What I want to bring out is that Type 31 is not Type 26 on the cheap – it will not have the same capability, nor does it need to . It should be viewed instead as the replacement for both the Type 23 frigates that are no longer fitted with towed array sonars (referred to as the General Purpose or GP frigates), and therefore shares greater ancestry with the Type 21 and 22 frigates, the RN’s workhorses for wide-ranging general purpose duties. It also reflects the consequences of the decision to abandon Type 26 as the single frigate design for the RN, which in turn undoes a lot of previous assumptions about warship design because in my opinion, the Type 26 has failed to achieve its intended design purpose.

ORIGINS – HAS THE TYPE 26 FAILED ALREADY?

Type 26, for all the hype about being a ‘global combat ship’, has missed its most important design objective by a country mile – cost. Considering the low-cost origin of the frigate it replaces (the Type 23), the decisions that resulted in that design and decades of operational and engineering experience, Type 26 is far too expensive. It was long advertised as a quiet yet inexpensive hull (with COTS/MOTS propulsion) into which existing, risk-reduced systems (i.e. every combat system on a Type 23 TA hull) would be installed – instead it has become an expensive behemoth. Nothing about the ship is novel – it is larger than a Type 23, but has only a slightly larger hangar-cum-boat bay (the vaunted ‘mission bay’) and a Mk41 VLS fitted ‘for but not with’ (and for which we have no weapons). The ‘mission modules’ that promise exotic capabilities in a plug-and-play fashion do not exist – look at the US LCS programme for examples. Acoustic quietening is neither novel nor difficult – with decades of experience in the Type 23 and submarine programmes we should have this addressed. Damage control measures are well understood, even taught to every serving sailor as part of the basic sea survival skills. And on top of this we have built four new classes of warship in the last ten years alone – the River OPV, Type 45, Astute and QEC. So where have we gone wrong?

We know the RN is under huge pressures in manning, and the retention of suitably qualified and experienced personnel, especially in the naval design area, is a huge challenge. And although the design is largely undertaken by the contractor, the RN still has a key input for standards and requirements to set the overall capability required from the ship. Since the experience already exists, can it be that the shortfall in SQEP design personnel, coupled with the RN’s continued manpower challenges (and frequent rotation of personnel) has led to changing requirements that, in turn, have driven major (and thus costly) design revisions? How else to explain a frigate design that (based on the contract signed for hulls 1-3) currently has a price tag of over £1Bn per hull, yet has little more capability than a Type 23? One does not have to wonder why the export potential for this design has evaporated (stand fast the Australians for whom Type 26 represents the only modern acoustically quietened option on the table).

I do not doubt for a moment that Type 26 will be exceptionally capable in its primary role of North Atlantic ASW, if the designed acoustic dampening has worked. The 2087 towed array system and the Merlin Mk2 helicopter, coupled with the P-8A Poseidon, will make for a formidable SSN hunter and deterrent capability. But it is excruciatingly expensive, and this role is one that occupies only a fraction of the current Fleet’s operational tasking.

The failure of Type 26 to meet its cost target has undone both the SDSR 2010 decision to merge the Future Surface Combatant (FSC) C1 and C2 designs, and the earlier Sustained Surface Combatant Capability (S2C2) design studies that proposed the C1 and C2 should share a common hull (make sure you have read Think Defence’s piece on Type 26 here – it is excellent). By opting for an all-new hull, we have effectively gone back over forty years to the early 1970’s and the decision to acquire the Type 21 and Type 22 frigates. So be it. At least, unlike in the early ‘70’s, the manner in which the RN now develops its weapons and sensors has made them platform-agnostic, with a common PDMS, close range guns, sensors, ESM suites, combat system, etc, so all we have to do is design the hull. But we still need something, and what we need is an escort.

THE ESCORT PHILOSOPHY

The operational model of an escort (feel free to call it a General Purpose frigate if you like) is well evolved in the Royal Navy. We started the concept with the Type 22 and Type 21 frigates. Both were rooted in the successful Leander designs and acknowledged that a common hull for AAW and ASW tasking could not be achieved (D K Brown’s book ‘Rebuilding the Royal Navy’ is a must-read. The excellent point made there was that Type 22 and Type 42 were roughly equal in size, yet markedly different in role and capability). Advancement in weapons and sensors, and the high manpower demands of steam propulsion, saw a generational shift to multiple weapons systems on one platform, the coming-of-age of shipborne helicopters, reduced complements and gas turbine propulsion. The capabilities on both Type 21 and 22 were broadly similar (although the decision to omit the large-calibre gun from the early Type 22’s was rectified after experience in the Falklands). They were highly successful and many of them are still in service (five Type 22’s and five Type 21’s). The philosophy continued into the Type 23, adding the specialist ASW capability that originated in the Type 22 Batch 3’s but optimising the hull for towed array work now that the TA design was mature. Forty years of escort operations, including several major conflicts ranging from the Gulf War to the Falklands and a total of 38 ships, has vindicated the philosophy of a surface warship that can operate independently, defend itself and others from attack, deter opponents and still deliver the UK’s foreign policy globally.

CAPABILITIES

Taking those requirements individually, the first is the ability to operate independently. This is nothing new – large fuel tanks, efficient engines, seaboats, RAS gear, cold rooms and fridges and adequate accommodation are obvious examples. Maintenance is a major limiting factor, but technology has evolved and gas turbines and diesels are as low-maintenance now as ever before. The complexity of some systems does demand more in the way of contractual support overseas, but so long as any design avoids exotic engineering solutions this requirement is technically simple. We know how to divide ships to enhance their survivability, thus enabling them to operate with damage (whether natural or from enemy action). The RN has the long deployment coded deep in its DNA; it is in the way we train and fight that allows us to operate so far from home for so long, and so long as we continue that ethos we can retain our global range and endurance.

Secondly it must be able to defend itself and other,s and in this I will consider above-water and under-water warfare in turn. Above water the threat is the proliferation of anti-ship missile types. Large and small, subsonic and hypersonic, old and new, these threats are considerable and long-ranged. An escort cannot deal with them at long-range and equally cannot defend a large number of units – this is why we have AAW destroyers (and Type 45 is one of, if not the best in class). But on isolated patrol and for small escort tasks, the Type 31 needs to be able to counter a moderately determined attack. This demands a radar, ESM surveillance and a weapon system – and the RN already has Radar Type 997, UAT (and evolving variants) and the SeaCeptor missile, all state-of-the-art, capable and entirely appropriate to an escort.

Underwater, the decision to split the frigate force into two types eliminates the acoustic stealth requirement (which may, or may not have been one of the cost drivers in Type 26). Type 31 will not be required to trawl a towed array and sit quietly in the Atlantic – that is now the preserve of the Type 26. The primary underwater threat the Type 31 will deal with is not the speedy SSN in deep water but the slow, silent SSK in the cluttered and deafening littoral environment, where passive ASW is nearly useless. Hull-mounted active sonar, ASW helicopters, radar and ESM, visual detection and speed/manoeuvre are more critical against the SSK; the acoustically stealthy Type 26 carries little advantage here, especially when the task is to escort and the defended asset is invariably very noisy indeed (not just engines but the radiated noise and energy from launching and recovering aircraft). In this environment the escorts will most likely be transmitting on active sonar, both to detect and to deter. Countering the SSK is like driving through a lawless city – most of the time speed and manoeuvre will keep you safe, but when the attack comes it’s a knife-fight in a phone box.

What the escort needs is the ability to react quickly to a submarine detection. Again, speed and manoeuvre figure prominently here as does the ability of a helicopter to react quickly and get weapons on datum. Against a concerted SSK attack we are likely to take hits, but submariners are not suicidally minded and if they are located they can be driven off or sunk in short order – there is nowhere to hide once a Merlin starts dumping active sonobuoys around you. If funding exists for the installation of the Mk41 VLS system and the acquisition of a weapon system for it, then the ASROC is a more effective alternative to shipborne torpedo tubes.

Last comes deterrence. The aircraft carrier deters but also presents an inviting target for attack. The AAW destroyer (and organic fleet air defence) offers the best protection from missile threats, and well-handled escorts and ASW aircraft counter the underwater threat. Thus the best offensive weapon that can be fitted to an escort is the anti-ship missile. If an escort can operate independently from the fleet, then the ability to range ahead and hunt enemy surface combatants is valuable, especially as many do not have AAW systems as capable as our own and the likelihood of a successful engagement is high. The RN continues to rely upon the venerable Harpoon for its anti-surface weapon, but wheels are in motion in the US to replace it and a new system may yet be selected. Whatever, an ASM is best suited to the independent escort and can be fitted with minimal difficulty, and thus ought to feature on Type 31 even if stocks do not permit universal carriage of live weapons by all ships at all times.

SECONDARY CONSIDERATIONS

I believe these to be the baseline, but other factors exist which bear merit. The RN still maintains an amphibious capability, and experience suggests that a large calibre main gun is worth having for the NGS role, especially if guided ammunition is available (in an age of political demand for precision). But the Type 26 and Type 45 both have large guns already, so could the Type 31 dispense with a large gun (as the Type 22 did)? Or could the 76mm gun make a reappearance for constabulary duties, noting that the Wildcat carries both Sea Venom and Martlet? A Type 31 with Sea Ceptor and Phalanx 1B (or a future laser weapon) could potentially sit much closer inshore than a Type 45, providing an air-defence umbrella to the raiding forces, although not at insignificant risk and requiring early warning from the Type 45 and any AEW asset that might be operating.

UAVs are becoming cheaper and simpler to operate. However, as yet I see no justification for major warship design compromise to accommodate any such system. The launch and recovery equipment for ScanEagle represents the likely top-end of assisted launching, and this fitted comfortably on a Type 23 without compromising helicopter operations. VTOL UAVs require only the hangar and deck. Whilst more might be argued if we embarked a Predator-sized UAV, the cost and risk is not justified at this stage.

Above all else it is a warship. Headline-grabbing disaster relief missions do not justify compromise in the warfighting design nor expensive additional capabilities – whatever they might be. At best, space to secure a couple of ISO containers containing relief supplies might be considered. Just don’t call it a ‘mission bay’. Counter-piracy is a potential task, but again the existing combat capabilities of the vessel should be more than adequate, perhaps only demanding additional accommodation for Royal Marine boarding teams. The one capability I would consider is a bow thruster. Warships tend not to have these (the OHP frigate was a notable exception), but the advantage of such a thruster is that the ship becomes less reliant on host nation support for berthing and unberthing – in a devastated port or deprived area, the ability to dispense with tugs could be invaluable.

WHAT THE TYPE 31 CANNOT BE

Anything less capable than the escort outlined above is a waste of money. At the first sign of an airborne threat, it becomes a liability. Equally an escort without at least some ASW capability is at risk the second an SSK puts to sea (the reverse of the CONQUEROR/BELGRANO case study). There is a clear minimum baseline capability to meet the criteria for an effective, globally-deployable independent escort. Type 31 cannot be an up-gunned OPV.

Type 31 is also unlikely to be a suitable platform for an AAW variant. The smaller size of the hull will limit the size and weight of any capable air surveillance radar that could be fitted, reducing the radar horizon and limiting the ability to detect low-flying threats at sufficient range. Weapon capacity is also an issue – Type 45 has 48 cells and is commonly regarded as having too few missiles, especially when compared to the Arleigh Burke’s 96-cell capacity. The Type 26, however, might be a better bet if that requirement ever became an option.

FUTURE PROOFING

It is difficult to future-proof any military system because of the long timescales involved in designing and building complex warships. But this is nothing new. By the time the County class destroyer was in service with the Sea Slug missile system, the latter was borderline obsolete already. Other examples exist, so the lesson should be to provide space for change, and influence developmental programmes to remain aligned to naval limitations. Exotic solutions tend towards failure – and here I would cite Type 45 propulsion, the Littoral Combat Ship and the cost of the Zumwalt destroyer as examples.

I believe that few, if any future game-changing capabilities are likely to require large, costly installations or extensive reconstruction. Even railguns, under development now, are unlikely to make a single warship suddenly an order of magnitude more effective – and they are under development, not ready. The best example I can think of is electronic warfare, including cyber capabilities. Such capabilities are only going to increase in importance, yet they require only server space, cooling and transmission systems – all of which exist already in a complex warship. A sufficient growth margin should be factored into power, cooling and aerial capacity.

And as our doctrine develops in response to Russian and Chinese progress in the past decade, technological innovation is now seen as the route to future battlefield success (the US Third Offset Strategy, or al least my understanding of it). I would argue that it is more critical to have a hull in the right place at the right time, otherwise no exotic capability is ever going to deliver an advantage. We cannot deliver effect with our stealth-swarming-self-3D-printing-drone-battleships if we only have one. We need the numbers to ensure that we can achieve a forward presence, and that in itself demands a low cost per unit.

THE ROLE OF INDUSTRY

The cost failings in the Type 26 design should tell us that we cannot approach Type 31 in the same way. If we set out to design a Type 23 replacement and ended up with Type 26, then Type 31 will also fail in the same way.

What is needed is the opportunity to pass the design process over to industry and accept that there will be compromises in the design that are not the RN way of doing things, but which can prompt adaptation and innovation as well. The National Shipbuilding Strategy outlined the potential for modular construction and assembly, and several promising designs are already on the table – the BMT Venator and Stellar Spartan stand out. BAE Systems has been predictably dull in its offering of modified OPVs and corvettes, and needs the wake-up call that Sir John Parker proposed.

The best approach would be to select a design and follow the prototyping or batch-building route. By ordering one, two or three initial hulls, we will at least acquire the basic platform and can understand it’s shortfalls as well as its capabilities. The proposed industry model supports this, as it will not leave yards waiting for work as they are able to return to other complex shipbuilding tasks in the interim.

Equally importantly, the RN as a whole should provide broad consultation on the proposed design to identify any significant shortcomings. This must be done in a controlled manner, by providing one or two contractually agreed input moments as well as a coherent and fixed set of design requirements at the beginning. Vesting this critical input in a handful of personnel (most of whom will not stay in that job long enough to see the final design, let alone the first of class) must not happen. Once the kinks have been worked out from the first examples, a modified design can be produced for the next batch. This also opens the way for export orders, as the design can be tagged as ‘developed by the Royal Navy, a powerful export incentive. The early hulls can either be tasked operationally or, if they are deficient in some way, kept back for lower intensity operations or sold to other nations who do not share our high specifications. The concept of Tranche 1, 2, 3, etc works in many other industries, and there is no reason why the Type 31 could not be the basis for RN escorts for decades to come.

By transferring the design risk to industry, following the build-assess-build model, selecting a baseline global escort that embraces RN experience and equipment, and maintaining key stakeholder engagement at all levels, an affordable, capable, appropriate escort frigate is achievable.

SUMMARY

Hopefully I have made a decent case for the minimum requirements of an escort that meets the RN’s requirement, and proposed a potential route to acquiring this at the right price by transferring design risk to industry but accepting certain compromises in design for the sake of platform development. I have made several assumptions about Type 26 which fit the overall picture I have gleaned from open-source and which provide a potential answer to the question of excessive cost. But the truth is that the reasons for the origin of Type 31 may never be made public, and so we are left to speculate.