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Armchair Admiral

Being a rum glass half full sort I will assume the budget will only stretch to 3p ammo. BUT, like the maths, possibly 30 rounds covering the path of an incoming missile, especially assuming a hypersonic one won’t be jiggling around much?

Considering that the GBI that defends against nuclear warhead missiles is the same principle, three rounds may be sufficient. Of course, detailed calculations of the radar must be involved, but the advanced technology can calculate evasive maneuvers before the final speed inrush.

Of course, if it is 20 km, the missile has already entered the terminal speed stage and there will be no evasive maneuvers.
(There is no need to intercept if the missile performs a rapid intercept evasion maneuver - perhaps self-destruct)

A fascinating article, obviously took time to research. There is an argument that the 4.5″ on the Type 45 be replaced with 57mm to reduce support costs. More likely on the Type 45 replacement.

Supportive Bloke

Only once the T45 has an AShM or land attack missile. But then the 57mm is a no brainer.


The 4.5” is very very unlikely to be fitted to any new ships. As to the T83 the proposed T45 development anything is possible in terms fitting (or not) of main gun systems. But odds on it will either be the 57 or the same 5” system as the T26.

Mr Bell

I would like the type 83 to have both types of guns a BAE 127mm (5 inch) for NGS and 1-2 57mm guns for surface strike and anti UAV, Helo, FAC. I think in a 8000 tonne vessel such equipment would be easily achievable in terms of top weight. The RN needs to return to a much more lethal weapons load-out and not just blindly stick to a single gun mount when weapons like the 57mm and 40mm bofors are both really adaptable and multi-purpose weapons.


Surly if costs were the big decision to put 57mm on 31 and the 127mm on type 26 and pre planned then once built could they just simply be swapped if needed, but I love the amount of lead it can put out if the Iranians or pirates get over zealous. Even at close quarters in the littoral zone round an island chain and come across some sort of amphibious brigade lying in ambush you wouldn’t want twin 40s and a 57 peppering your beach head. Boom boom boom boom..
Its an excellent choice of weapons systems. Now we just need a T83 cruiser/destroyer with 100+ vls for land attack and air defence. Any more details out yet on T83?


You definitely couldn’t easily swap the systems. The T26 is being built to incorporate an advanced unmanned shell handling system/magazine. You couldn’t swap this without cutting the front off both ships.
T83 is at an early stage it would be a bad idea to decide anything this far out from the start of build. If you do you run the risk of the ships being obsolete on entry into service.


I’ve long been impressed with the capabilities of this excellent weapon system. Indeed, my only issue with the RN’s current approach to the matter being that I dearly wish it had both been adopted earlier, and also emplaced far more widely in the fleet. In a world where warships face a ever increasing threat from advanced hypersonic missiles it will be interesting to see how long gun based defences can remain effect before – presumably – directed energy weapons eventually replace them.

In the short to medium term replacing outdated PHALANX 20mm CIWS with the Bofors 57mm would appear to be highly desirable.

Gavin Gordon

Bofors replacement for Phalanx likely a good option. But would think the 40mm perhaps a better mounting for the usual 20mm CIWS locations.

Mr Bell

Agree Gavin the 57mm gun although accurate doesn’t have the weight of fire for CIWS- the 40mm bofors on the other hand most definitely does.


well, atleast the twin 40mm with up to 900 rpm of proximity frags


I doubt any existing ships will get either Bofors. If the T45 was going to it would need to be done with the Sea Ceptor project. It’s probably to late to add it now without delaying things. The same applies to the early T26.
The other problem is as always money. The RN and the U.K. Mil in general will do well to get the extra money needed to cover high inflation never mind new expenditure. The current government is far more concerned with funding skin saving tax cuts than increasing the defence budget.


Nice article, eagerly awaited and didn’t disappoint.

The argument that Type 31 should have 5″ and T26 should have 57mm still strikes me as a good one. When all 13 frigates were expected to be Type 26s, the 5″ gun made far more sense. It’s too late to change the Type 31 contract, but if the money is there for the 5″ guns on the T26 batch 2, perhaps they could be swapped into the T31 instead. The biggest issue is that any success in arguing the 5″ gun isn’t needed on the T26, will encourage the bean counters to not have it on either. Hopefully though they’ve already been ordered along with the long-lead items.

Last edited 2 years ago by Jon
Dave Wolfy

Would anybody risk a Type 26 close inshore doing the bombardment job?
The Type 26 would not be doing its primary role that close inshore either.
The Type 31 with the 127mm does make much more sense.

Last edited 2 years ago by Dave Wolfy

Swapping 57 mm and 127 mm gun of T31 and T26, respectively, is not attractive for me, not at all.

T31’s ASW capability is none. What if there are any ASW threats (including UUVs)?
T31’s AAW capability is low. What if enemy has a battery of ASM on land?

I think the case RN needs T31 for NGFS is very niche. (not zero, but…)

  • the enemy anti-ship threat level must be “not high but still there” (you do not want to risk T26/T45 = so-so threat, but the T31 can survive = low level)
  • the enemy is “a little powerful” so you still need NGFS (in addition to air-attack and/or RQ-9B-like UAV support)

What kind of theater it is?

One candidate is “very low/zero anti-ship threat” case, like Pacific islands. The conflict is so low-level that RN will NOT send CVTF. A T31 with 127 mm gun can support a platoon of RM or SBS doing land-attack. This is what the French Floreal class is designed to do, to my understanding.

In modern Falkland war case, if we use T31 like RN did in 1981 with T21 (doing NGFS when still enemy retains significant air-power), it will immediately sink. But, as RN now has CVTF, it will not happen, and precision air-strike and drones will do all the job well. If needed, T26 can do NGFS.

Of course, T31 with 127 mm gun can do something. But, for me, its very niche cases.

On the other hand, T31 “as is” is optimally designed for Persian Gulf, Oman, Yemen, Red Sea tasks. Fast boat swarm, UAV attack, occasional ASM attack. T31 can perfectly handle this, even much better than T26 or T45 can, thanks to its 1x 57 mm, and 2x 40 mm guns, supplemented by 12 (or 24) CAMM. As its equipment is simple, it can be operated with less crew, less cost and less maintenance (at port). Replacing 57 mm fun with 127 mm gun will significantly reduce its usefulness.


Please let us know if there are any missiles like the Air to Air Brimstone that will be mounted on current or future drones.

Of course, more than 20 kilometers

There may be drones with radars that are capable of laser guidance or RF guidance from at least 60 km.

What you’re talking about is a possible scenario for large drones, and those that don’t exist within 1-5 years from now. And large drones are a problem that can be intercepted with the SEA Ceptor for ships such as Type 26 and 31 that monitor air defense areas of 100 km or more.

The Bofors Gun is a CIWS, and it will be sufficient for the next 10 years.
it will be too enough


Except the T31 is expected to last longer than 10 years. If any RN ship is likely to be put into a position where NGFS is required, it’s the T31. However, everyone will have to wait for France to bring up a light weight Floreal patrol frigate to do the job. Makes no sense. It’s outgunned by most OPV’s in the Indio-Pacific.

Meirion x

A 5 inch gun is just not for shore bombardment only!
The gun can fire guided ammunition, like mini depth charges. Handy if a sub gets too close, a shake-up I say!

Last edited 2 years ago by Meirion x
Dom Hyde

I would check your facts, lest you look like a loon. The Kingfisher program (those depth charges) has not really produced results to date. Sonobuoy firing trials were ‘planned’ in a press release of November 2020, but there’s been nothing public since. It’s basically still a concept, not hardware.

Last edited 2 years ago by Dom Hyde
Mr Bell

Maybe the type 32s could get the 5 inch gun if budget allows- I like the idea of the type 31s being a patrol ship and in times of war shotgun escort for QE class carrier or an Albion/Bulwark LPD acting in amphibious warfare command role. The weight of close range point defence fire coming from sea ceptor, 40mm bofors and 57 mm guns are going to be devastatingly effective.
Or we could get 3 or 4 more type 31s added to the order optimised for surface strike as detailed above. take across the mark 8 guns from the type 23s and use up the plentiful supply of ammo still in stock. 2 mark 8s per surface strike option and 4 x 40mm bofors are going to be a really effective NGS platform.

Mr Bell

I think the 5 inch gun is going to be used in the ASW role via Kingfisher advanced ASW rounds- so depth charge and micro- seeking torpedoes with a 3kg warhead- they aren’t going to sink a sub but they might make its performance much impaired with peppered hull breaches thereby enabling a kill via a helicopter or ASROC from mk41 VLS.


Excellent article thank you.

my only gripe is we are introducing another small set of equipment and perhaps we could have standardised all vessels on the 76mm Otto and 40mm CTA and standardise all our forces on one common platform, instead we have added 2 new ones when money is tight.

even adapting a 155mm shouldn’t be too hard in reality, especially given the recoil mitigation systems now in service, this would standardise even further saving cost.

at some point we need to stop wasting money on buying several products that do essentially the same thing and this is a prime example. I Know CTA is expensive, but we have committed to it and have the ammunition factory in the UK, the more we buy the cheaper it becomes.

your point on the127mm is a good one, as we have paid for 8 of these perhaps we should move them onto T31 to get that balance right across the fleet. T26/45 are too expensive to risk close in so the reality is they will rarely use this capability in anger, if ever.

given both are BAES products I am sure this is doable at minimal cost for what would be a big issue increase in overall capability – RN take note a very good idea let’s see if the organisation is agile enough to implement it.


I’ve been wondering about the CTA 40mm too. Not an expert but it seems odd both Army & Navy getting new 40mm & not just getting the same gun (since Bofors already do land & navy 40mm & Nexter are already offering a naval CTA turret). Perhaps their individual needs are best served by the different products but as a novice, I don’t see how.

RE the 127mm – if fire support is all they are to be used for, I would agree – I’d much rather risk a T31 close to shore than a T26. However, if you take a look at the Kingfisher programme BAE are working on, in the near future it may be possible to fire a sonobuoy 30+ km, ID a sub & then fire guided depth charges to kill it. All fired from the 127mm. That seems like a capability I’d want the T26 to have over the T31.

I’d be very curious to see what savings there would actually be if the RN+Army unified their calibers. My guess would be that since both will be ordering significant numbers of rounds, it wouldn’t actually be that much of a difference in the grand scheme of things. I’ve not seen any data on this so happy to be corrected.


The CTA is as yet unproven in Naval service. But we do know the ammo costs an arm and a leg. For the army the packaging advantages are a real plus on vehicles, I’m not sure the RN would get much out of that.

Paul Bestwick

I understand it the range of the 40mm CTA is up go a third less than the 40mm Bofors. From that point I think that makes it understandable why the RN went the route they did.


AH! It’s a ‘range’ thing. That answers that then. Cheers for the info.

Just me

No, it’s a speed into action thing. It takes 2 seconds to bring up to its pedestrian ROF speed,

Craig Lewell

Fantastic post! I’d not heard about the Kingfisher programme, a great nugget of gold when lots of us have been scratching our heads over how the Type 26 will sink subs if the Merlin is not available for whatever reason ?


I think you are both overestimating the capability of such a system! There is a reason why we use helicopters to hunt and kill SMs. They are on the scene able to react and deliver both sonobuoys and torpedos accurately. They are likely to be aided by some form of ‘drone’ in the future.
Anything fired from a 5″ gun will first of have to withstand the immense forces imparted on firing it-not good for delicate electronics!!
Delivery of such stores will be highly inaccurate, when you need accuracy, sonobuoys have a v short detection range as it is, hence we use helicopters for it.
As for a depth bomb, it’s charge will be relatively small, 3-4kgs at most, that will hardly scratch the pain. Even if they fired 10-15 of them, the net result is lots of small explosions rather than a large killing one. There is a reason why torpedoes have large warheads, often with shaped charges, so that they stand a good chance of a first time kill.


Understand the concerns.
Re ‘delicate electronics’ go and look at the Excalibur round. Already in service. Not the only round with similar abilities either. They’ve made 155mm shells that can identify and then steer itself onto a tank…
Re the ability to kill, shaped charges could punch through. Once you weaken/penetrate the hull, cracks lead to catastrophic failure.
BAE only spend/waste taxpayer money. Little chance they’d be spending their own cash developing this if it wouldn’t work on paper.
No idea where you’re getting the idea that artillery is inaccurate… even dumb rounds first shot will hit within 20m these days.
Regards Helicopters, agreed. They’re the obvious first choice. BUT if that’s the case, why fit towed sonar? Hull sonar? Why make the ship quiet if it’s never going to get anywhere near a hostile sub? T26 needs Kingfisher (or similar) and/or ASROC and/or torpedo tubes for those times where you don’t have 15 minutes to launch a helicopter, or the helicopter is broken, down for maintenance etc etc.


Sorry, my poor explanation of helicopters use. They don’t really have the endurance or systems to go out and search for a SM by themselves, every acoustic sensor they carry is relatively short ranged, so they need queuing onto a datum point to start searching. This gives them a reasonable chance of finding the target.
Understand about ‘Excalibur et al’, a sonobuoy is a different prospect, which is why it hasn’t been done before. To be fair, they might eventually get it to work, but if you have a TA, why would you need it. It wouldn’t be your primary search method, as the detection range is v short when compared to a mainframe sonar or TA. If you didn’t have a firing solution, where would you aim at?
Land based artillery might have a accuracy of say 20m or so, but at sea it will be far greater. First there is detection sensor inaccuracies, the greater the range from detection sensor, the greater the range inaccuracies. A ship at sea is not a stable firing platform, so there is another inaccuracy. Once the depth charge hits the water, it sinks, so no guidance, hence v inaccurate.
Shaped charges on torpedoes or indeed AT missiles are propelled at great speeds, contain lots of kinetic energy, which helps the initial penetration, said depth charge only has the rate it sinks at-not v fast, it also has to land on top or just in front of the SM which is moving and at a unknown depth, highly improbable that it will get anywhere near a SM.
Get it point about getting a helicopter airborne and to its search area, but I imagine a ‘drone’ with a long loiter time carrying sonobuoys/lightweight torpedo is probably a better proposition to assist helicopters with ASW warfare.
That’s my thoughts on it.


Sonobuoy has a detection range of about 2,000 yards (and that’s what they tell us so it’s probably more). We can absoolutely hit this circle.
5′ gun rate of fire is 16-20 rpm. The gun is stabilised. So you have an inkling there’s a sub, you don’t fire 1 sonobuoy. You fire a pattern of sonobuoys to locate it.
“Hasn’t been done before” – pre-1969 we hadn’t been to the moon. BAE are paying for this themselves so they clearly think it can be done and that it’s a product that people will want to buy.
“Shaped charges” do not rely on kinetic energy for their penetration. Carl Gustaff rifle. HESH + HEAT rounds. NLAW doesn’t touch the target before detonation – fires a shaped charge downwards from 6ft above the tank.
“Land on top… unknown depth” – it is a known depth (but that’s actually irrelivant) – that’s what sonobuoys are for.
“it sinks, so no guidance” Look at the images & you’ll see fins. It’s not 1942 so they’re not planning on just lobbing explosives around & crossing fingers. I’m guessing their idea is to have a small seeker on the front & use the fins to steer it as it falls. If they can make a seeker that can survive firing (they already can) with a 35 degree field of view, fired at a target at a depth of 150m, you’d have to land rounds within 100m to enable to seeker to see it. We can absolutely be this accurate, especially when firing multiple rounds – if we couldn’t, the whole idea of NGFS is BS
You’ll also see on the images what appear to be a UUV. If you read up the limited information available, there’s ideas floating around about this being a point defence type system for torpedos too. None of those ideas have a hope of working without some form of guidance, steering etc.
I’m not saying this is the panacea. I’m 100% behind the idea of ASROC, T650 (or similar) and Merlins doing what they do. I am saying it’s a potential upcoming capability that the RN should keep an eye on and would be better suited to the T26 if/when it matures as another layer/capability.

Just me

40CTA has no anti air mode against fast targets.

Jim Jones

An Idea would it possible to put the five 57mm they have already ordered on to the Batch 2 River call to give them a bit more that just a 30mm. Then replace the the 57mm on the Type 31’s with Otto 76mm, the RN used them on the old HK boats and there are several NATO navies that use them, so qualification courses to start should be to onerous.

  1. What would you use to pay for this plan?
  2. What part of the B2 Rivers mission needs a 57? Remember the are patrol ships for low risk areas only.

So you’d add another calibre? The HK boats went 25 years ago.


Replacing the 30mm on the River 2s with the Bofors 40mm would make more sense.


For whatever replaces the Rivers in 15 years maybe but why spend anything on them now? For what they do, 30mm is fine.

Same with the MCMV’s. If we get to replace the MCMV & OPV’s in the future, sure – go 40mm.


Can always add sea Brimstone launch rail to give it a bit more teeth like we planned to do with the Ukrainian P-50u. Or even the martlet attachment for the 30mm.


The missions of the River class are:
Fishery protection, border enforcement, anti-smuggling and anti-piracy, maritime security and disaster relief.

So the opponents the River class will face are:

  • French and Chinese fishing boats (armed mainly with swear words, tins of food and using the boat itself to ram)
  • Illegal migrants in small boats (armed only with hopes and dreams)
  • The French Maritime gendarmerie’s speed boats and other inshore patrol vessels in places like Gibraltar (armed with mounted 7.62mm & 12.7mm machine guns)
  • Drug smuggler’s boats (armed with small arms)
  • Pirates (armed with small arms and RPGs… by far the most potent weapon against a 2,000t ship)
  • The weather (by far the most dangerous to a patrol ship in places like the South Atlantic… But not something I would recommend shooting back at!)

None of these requires anything more than a 20-30mm gun and some blokes in a speed boat with small arms… Both of which the River class already has, so it’s fit is well suited to it’s task. The only things I would chose to add would be some kind of small reconnaissance UAV (preferably with thermal imaging cameras) and the LRAD, a non-lethal deterrence device which would be quite useful to (for example) break up French fishing blockades without having to shoot anyone or anything and cause a major international incident.

IF you’re worried about someone like Argentina (ie any real navy) getting uppity and kicking off another shooting war, no 40mm, 57mm or 76mm gun is actually going to help an OPV (or even a full frigate) against overwhelming odds, so why would you waste money giving them capability they don’t need for their intended purpose, and wouldn’t be effective when used outside that purpose anyway?
We have much more powerful ships, not to mention some of the best submarines in the world to engage enemy navies with.

Last edited 2 years ago by Jim

One addendum, the Navy have said they will be getting MAD-FIRES to complement the Sea Ceptors on the T31s.

The BAe/Bofors 57mm can also be fitted on to a pedastal magazine. This holds an additional 120 rounds and is fitted under the mount, but above the deck. This increases the round capacity without penetrating the deck.

The DARPA/Raytheon MAD-FIRES round is a rocket assisted guided sabot. Raytheon are being cagey about its guidance method. Saying that they have used existing technology from their air defence missile systems. Therefore, unless they have managed to shrink an active radar seeker into the sabot. Much like Leonardo’s DART, it uses semi-active radar homing (SARH). Besides SARH is a lot less complex and cheaper than using an active radar seeker. The ship’s radar illuminates the target, and the shell steers itself towards the reflection. According to Raytheon, due to the rocket assistance, it should have a further effective engagement range than the comparable DART, but also a reduced time to target.

It always makes me laugh when someone states that a 57mm gun can land more explosives than the comparable 76mm gun. That may be true, but the killing power is a lot less, due to the smaller blast radius and inability to penetrate as deep. The 76mm HE shell contains around 750g of RDX compared to the 57’s 450g (3P), so less shells are required per target. They also have a better penetrative capability against concrete, unless you can guarantee each shell will hit the exact same spot.

I think it is too soon to state that ship to ship artillery duels are a thing of the past. If that is all your ship is equipped with, then that is what you must use. Canada did a live fire exercise against a decommissioned frigate, using 57mm, 76mm and 127mm guns. The 57 drilled holes in the ship, the 76 did larger ones, whilst the 127 took out chunks. None of them did enough damage to sink the ship, even though over 50 rounds from each weapon were fired. There is a more likely chance, that even the 57mm can achieve a mission kill, if it hits the right area.

To my mind the Navy have got the gunboat frigate arse about face. The ship should have two 57mm systems, one forward in the traditional B position. With the other replacing the 40mm on the hangar roof. This would give the ship a 360 degree field of fire and multi-shot capability against multiple and high speed air threats when firing the MAD-FIRES shell. The two 40mm guns should be fitted port and stbd amidships.

This clearly leaves the A position empty, which could be filled in time with the 5″ (127mm) gun. Or if BAe dust of the marinized 155mm gun.

The T31 when coming in to service will only have one primary radar, the Thales NS100. This is an excellent multi-role radar. But, if it suffers a mechanical fault or gets damaged, the ship’s air defences will be relatively blind and then reliant on the electro-optical turrets for detecting and tracking threats. Like to see how that performs in crap weather! The ship needs a second radar, that can be used to compliment the NS100 and is available if it fails.

I do however, believe that the Navy should look at standardizing the 57mm gun. Therefore, fitted to the carriers, amphibs, OPVs etc. When combined with a tracking radar and MAD-FIRES, it would give the ship a more effective air defence capability.


57mm on the hangar roof – would this create a top-weight issue? And how much ammo can we get up there? Enough? There’s the age old “cost” issue too.

Regards radar – agreed. I’ve no issue with replacing Phalanx with 40mm + 3p ammo. Engage threats further out etc. Quite like the idea of phasing out phalanx & the 30mm for the 40mm on future ships (saves space, multitude of calibers, fewer systems to learn etc).

BUT a big advantage Phalanx has was its own radar enabling it to detect and target threats independently of the ships systems. In the event the NS110 does have any issues, you’re not a sitting duck as long as the Phalanx has power. Not an impossible problem to overcome though & an additional short range radar wouldn’t even necesarily need to be mounted on the gun itself.

Supportive Bloke

I agree with the BUT but I also agree with ATH that an all singing all dancing T31 morphing into a T26 lite simply would not have happened.


I agree, The Navy “NEED” to get the hull in the water, and also for the ship to be delivered on time and to budget. Once the ship is in operational service, then upgrades can be added, which will come from a different budget.


I agree. I didn’t make it too clear at all did I, but the ‘cost’ mentioned was getting at that.
I also agree with ATH, they are being built to a price so there’s only so much we can get. Doesn’t stop the lack of an independent CWIS radar for the 40mm being a possible problem.

Supportive Bloke

The 57mm has its own radar to follow the rounds.

So that may well be CIWS repurposed.


I’m not sure it could that detect an incoming missile. Not an expert (obvs) but I thought it had to be queued to a target & then the radar tracks the trajectory of the round onto the target.

Ian M

Hi SB, it’s a muzzle velocity radar like MVMD on an AS90 to enable the Fire control system to adjust for barrel wear, not to track targets.


The Mk3 turret holds 120 shells, if the pedestal magazine was included as well, then that would be 240 ready shells. As stated above the turret weighs 7000kg without ammunition. A shell weighs 6.1kg, so 120 x 6.1 = 732kg. This means a singular mount will weigh around 7732kg when loaded. If we include the pedestal magazine that holds another 120 shells that’s 8484kg. Would the pedestal magazine unloaded weigh more than 500kg? Could the T31 handle an additional 9000kg-ish of added top weight when added to the hangar roof? Time to put the model in the tank again!

Definitely agree with Phalanx being a stand alone system. The combination of an organic search and tracking radar married with day/night camera, means it can be relied upon when there’s an issues with the ship’s primary radar. The issue the system has is the 20mm gun’s effective range. If the 40s could be fitted with a organic search and tracking radar along with some optics, I would be much happier. Having a X or K band AESA fitted to the 40’s turret along with the guts of an EO turret, along with its laser designator, should be more than doable and at a reasonable cost. Making sure the system can be powered from a battery bank would be even better for battle damage redundancy.


Cheers for the info. So we’re looking at 9+ tons onto the hangar + the 9 tons from A mount raised to B mount + 2 x 40mm mounts amidships + the 5′ gun in A mount was Dave B’s idea. Defo need to put that into the tank again 😀


I would point out that the ship (A140 / IHF) was designed to take up to 127mm (5in) at A & up to 76mm (3in) at B. Not so sure about 9t on top of hangar (perhaps NAB could weigh ? in here). An alternative would be to start with 57mm at B & 3 x 40mm (2 amidship & 1 on hangar roof). Leave A empty for future 127mm. Just a thought.

Mr Bell

The type 31s are big warships- some 5400 tonnes, the Danish Iver H class already have a 5 inch gun in the A position- so that is a given. The hangar roof 57mm gun mount would be possible I’m sure as would retaining 2x40mm bofors and 2x ciws amidships. There is still space on the type 31 between the hangar and the funnel also to fit a 32 cell mk41 vls- so there is more than enough top weight and wide margin on the type 31 for future upgrades and for the ships to morph into full fat heavy combatants in due time. Budget and resources being made available from the mandarins and penny pinchers in the treasury of course.


You realise that a ship equipped this way would have been guaranteed to lose the competition?
It would have come in way way above the specified budget. If by some miracle the budget had been significantly increased you would have looked differently at the whole ship. Would it have been better to spend money on guns or on a lower noise hull/drive line in order to get some real anti sub capability.
But this just dissolves into fantasy and warship porn. The fact is that 5 ships within the budget was an overriding requirement.


“One addendum, the Navy have said they will be getting MAD-FIRES to complement the Sea Ceptors on the T31s.”

As far as know MadFires is a DARPA programme, Pentagon’s Defense Advanced Research Agency, basically its in the prototype stage, no sign as yet if US Navy will adopt it and make it a program of record. Think very low on USN priorities at the moment as they are currently fighting a battle with Congress to dispose of seven of their LCS ships with the 57mm guns.

So for RN to say they will be getting Mad Fires at the moment seems like wishful thinking.

PS To be noted USN buy the $13 million (FY23) Mk48 system, which includes not just the Mk110 57 gun but the fire control system, the Mk160 gun computer and the Mk20 Electro Optical Sensor System, have seen no mention of equivalent fire control system to be fitted to the T31.

Supportive Bloke

But the 57mm has been paired with TACTICOS before?

So why would we want to use the USN solution which then takes us away from sovereign tech and back to FMS…..?

BOFORS is a BAE company so they would also know perfectly well how to interact it into their proprietary RN CMS?


The T31 is getting the Thales TACICOS not the equivalent BAe system.


It was the then 1SL who said the T31 will be getting MAD-FIRES. Whether a contract has been written and agreed, who knows?

Supportive Bloke

At some point RN needed to reverse a warship into a budget!

At least it is done.

With data links and drones one radar down is less of an issue.


You make a good point on FMS, but my concern is that for more than a few years the DOT&E reported that during the trials the 57mm guns on the USN LCS’s was unable to hit their targets before they sorted it, changed the FCS for the 57 on the Constellation.
In light of above don’t think its a taken the FCS and sensors used on the T31’s for control of the guns will be any more successful than US first system until proven otherwise, emphasises once again the importance of testing. T31 only fitted with two Miradors EO for surveillance, tracking and fire control and yet it has three guns?

Supportive Bloke

It might well be another good reason why the US systems are not being used?

BAE Bofors make the gun so it won’t be a mystery to them how to control it.

TACTICOS is pretty open architecture.

BTW RN NGF was generally considered in advance of USN efforts during the 1980’s – US was very missile focussed. RN was very focussed on the accuracy of the 4.5” system.


Yes. As I mentioned to SB above. Getting the five ships in to service on time and to budget is the priority. Once they are in-service, then upgrades can and will be added from a different budget.


Smaller calibers provide less recoil and more precise accuracy.

This results in more rounds per unit time, meaning more results can be achieved with less effort than larger caliber guns.

One thing to keep in mind is that the battleship’s main gun must be active on the sea, which is constantly shaking – which interferes with the precision of the main gun.

Just because more shots are possible per unit time, this is definitely an advantage.


You also need to remember that air cooled high velocity weapons when fired at a high ROF, cannot sustain that rate of fire for very long. A 57mm can throw out a good amount of weight (AA) for about 10-12 seconds. Then it stops firing to avoid cook off. It cannot start again until the barrel cools down. The water cooled 76mm can keep firing until it runs out of ammo. The 57mm sounds impressive, for all of 10 seconds & even then not by much. Add in guided 76mm Volcano rounds at 40km. Even an upgraded 76mm Compact at 100 rpm & 4AP will outdo a 57mm with 3P over 20 seconds & can still use Volcano & SAPOM-ER. As a CIWS, a 57mm is reasonable, as a frigate main gun – not so much. It should be noted that the USN frigates expected to be fitted with it, carry 16 NSM. They have an alternative. T31 – zero alternative.

Depending on the target, hitting it more often with a lighter round does not necessarily mean it is better than once with a bigger round. Afghani with a 5.56mm is a well known example. Or the Canadian navy live fire tests.


“Despite its smaller calibre, the 57mm Mk 3s’ high rate of fire can deliver a greater weight of explosive onto a target than the ubiquitous OTO Melara 76mm.”

First the round weight is also part of effects,
Second the 57mm is air cooled so the 220 rpm are nominal, the gun even if it had 220 rounds to fire it could not do it in 1 minute due to heat.
The Oto instead is water cooled so can fire much more sustained.


Sorry Alex, replied before I saw your post.


USN took the 57mm out of Zummwalt because they said the 30mm was equivalent. But that sounds suspicious.

The following is NAVSEA’s complete statement to USNI News:
At the time of DDG 1000 Critical Design Review in 2005, the MK110 (57mm) close-in gun system (CIGS) was selected to meet the DDG 1000 ORD Key Performance Parameter. The basis of that decision was the expected performance of the gun and its munition, coupled with desire for commonality in USN and USCG. Through 2010, various analysis efforts were conducted to assess the performance of potential cost-saving alternatives to the Mk 110 CIGS, for both procurement and life-cycle costs. The results of the analysis for alternative systems to the MK110 CIGS were not conclusive enough to recommend a shift in plan.

A follow on 2012 assessment using the latest gun and munition effectiveness information, concluded that the MK46 was more effective than the MK110 CIGS. Based on that assessment, approval was received to change from the MK 110 CIGS to the MK 46 Gun System. In addition to the increased capability, the change from MK110 to MK46 resulted in reduction in weight and significant cost avoidance, while still meeting requirements. DDG 1000 is planned to have two medium range MK46, 30mm Close-in Gun Systems that will provide a robust rapid fire capability and increased lethality against hostile surface targets approaching the ship.


Centreline mounts make so much more sense for complimentary arc’s of fire than the current port and starboard arrangement.

It would make sense for the RN to standardize down to 40mm for smaller vessels and as a CIWS, 57mm for larger vessels and 127mm for NGS.

To echo many other comments I think the main problem is that 127mm will be stuck on very expensive ASW frigates that will have to focus on protecting the carriers / amphibians whilst it would make much more sense on the cheaper T31’s that we’re told will act more on their own, forward deployed and in littoral environments.

40mm/57mm would absolutely suffice for T26/T45 that will never be risked anywhere near an enemy coastline and will act in a purely defensive posture aside from any cruise missiles they eventually receive which can be launched from hundreds of miles away!


I do think, “57mm gun for T31” and “127 gun for T26” is nicely matched. No need to swap it.

T31 is well designed to perform asymmetric/gray-zone warfare. Countering Iran, Red Sea, Hormuz strait as such. Fast boat swarm, suicide UAV attack, and occasional ASM attack. T31 equipped with many short-range firepowers is the best suited for such tasks. T31 can handle them much better than T45 or T26. No need for NGFS, because UAV-based precision attack is the normal solution in such a gray-zome theater.

T26 and T45 are well designed to fight a real war. If any NGFS is there, it shall be done with them. In war time, good AAW is needed to do NGFS. If enemy has any SSK, good ASW might also be needed. Hence, T26 and T45, both with much better AAW than T31, and T26 good at ASW, are the best suited assets for it.

I’m afraid, in modern war, if RN use T31s (when replacing the 57 mm with a 127mm gun) like they did with T21s in Falklands war, the T31s will be easily sunk.

If 127 mm gun is needed for T31, it is to do so as “queen of the ocean” in threat-less theater, (like south Pacific) to provide NGFS supporting RM small unit. Good example is French Floreal class. But, Floreal-class is not good at countering fast-boat swarm, and very vulnerable against ASM and UAV attack.

Compared, T31 is very well suited there. Just fit for purpose. In short, I think T31 is well suited for the tasks they are designed for. But, it simply is not the same to Floreal class.

Last edited 2 years ago by donald_of_tokyo

Agree the t31 was designed to do the commonwealth tasking roles of anti piracy and drug busts along with humanitarian disaster relief missions and waving the flag in far off places 95% of a naval frigates duties don’t require big guns at all. Escorting the CSG requires a who different set of weapons and sensors which T31 was not designed for.

Fred the Frog



I’m not sure why you would call it commonwealth tasking, it sounds very old fashioned and a bit condescending. Most likely spots to find T31’s are the Gulf/Red Sea and Pacific.

Last edited 2 years ago by ATH
Nick B

which are exactly the places they’re under-armed and under-sensored for. The Caribbean Patrol, anti-piracy off Somalia (or west africa where is a large problem now), Falklands, Med patrol etc is the only place they should be deployed at current design spec (IMO)


I doubt the T31 will spend much time in the Falklands or Caribbean, they are very low threat areas well served by the B2’s. Gulf, Red Sea, West and East Africa plus the Pacific are far more likely focus areas for the T31’s.


Not a good option for the Pacific. May as well send a River B2. There is a reason the French fit their Floreal class with a 100mm. You send a T31 to a Pacific Island, all it can do is sail around it. A Floreal class is capable of serious damage while staying out of range of man portable weapons.

Supportive Bloke

If things got hot T31 would be shepherding RFA and STUFT?


Smart joined up comments, how refreshing!

Fred the Frog

I actually think that in Royal Navy use back then, they were catorgerised in Inches but heck, what do I know ?

Commonwealth Loyalist

Great article very interesting.

One small typo re the weight of a 10 second burst is off by a factor of 10, it ,


Yes. A 10 sec burst at 4 rounds per sec and 2.4kg per shell is 96kg. But I imagine its more likely to be say 5 or 10 round bursts for aerial or fast boat targets. The 10 sec burst is still very effective against land targets if you have a small spread of impacts


I did count the weight of shell, 2.4 kg. The explosive weight is smaller but the shell casing is usually what causes the most damage when the explosion happens.


The article doesnt mention the ‘cost per mount’
The UK style procurement cost includes life cycle and entry into service as well as production cost so can appear inflated
US procurement is more closer to ‘supply us with X number’ so is a realistic per mount value
For the Constellation class , for the first 2 ships, the contract was US$26 mill., so a starting number could be$13 mill each. Theres costs to build the deck mount and ammunition supply ( hopefully supplied with gun) which could be around the same

Replacing an existing gun mount is even more expensive to install, so you can see what that wont happen


Dont need the range of 15 km. CIWS is for the last few Km


But, that last few kilometers is all the ASM defense the QE2 class has. Defending against a large volley of incoming ASMs, many likely to be supersonic, with three CIWS is rather risky.

To defend a carrier, you want defense in depth. This why US Navy carriers are armed with deck-launched ESSMs and SeaRAM in addition to CIWS. Your CAMM-ER would be a good fit here.

This would also provide some defense against other types of threats like helicopters and drones.


Thats true. However the ‘SeaRAM’ variant which has its own independent targeting system is for destroyers and LCS. The Carrier uses the missile equipped RAM Mk31 as well is the cannon Phalanx

Nick B

Since money (or rather the lack of it) is the primary driving force in the RN, surely it makes more sense to reduce the number of gun systems in operation.

I would suggest focussing on the

  1. Mark 45 mod 4 with guided ammo for all large warships
  2. A 30 or 40 mm for patrol ships and secondary armanent on larger vessels (the Bofors 40 chosen for the T31 looks interesting as a new standard) ? combined with Martlet ? and
  3. upgraded CIWS for final defence

If its to be the 57 mm system, then we should surely buy more than 5 or 6 units to minimise life time cost of setting up new maintenance and logistics requirements for the ammunition alone. It seems we have forgotten all of the basic lessons.

BTW unless the Mark 45 in Type 26 are intended to have an anti-ship role via guided ammo, then putting that weapon on the Type 31 makes much more long term sense. I very much doubt the RN will able to keep the Type 31s in the role they are clearly designed for and I dont believe that they will be upgraded or fitted out for the extra capabilities to become equiavelent to Ivor Huitfeldt class in practice. The money will be spent on the Type 32/84 sometime in the 2030s.

The UK Govts political reach continues to be much much larger than our actual capbility to deliver anything and without spending at least 1 % of GDP more on defence, the large scale modernisation and expansion of the UK armed forces as a whole will never actually happen.

Last edited 2 years ago by Nick B

Non of this would have been possible within the very very tight budget cap for the T31. How the gun armament of the fleet will develop as new classes come into service will be interesting to see. But other than the announced retirement (and presumed) replacement of the 20mm I doubt money will be allocated to re gun any existing (or under contract) ships. The logistic savings would never pay back the capital over the remaining life of the ships.

Nick B

Agree. I was thinking on a going forward basis. The Type 26 are getting the curent 30 mm gun plus Phalanx. If we’re adopting Bofors 40 mm are combined secondary and CIWS from Type 31 onwards, then with only 1 Type 26 actually largely constructured, then when will there be a better type to simply and reduce maintance and logistics cost ?

Meirion x

Guided ammo for anti-sub, as well as anti-ship.


WHen I watch them firing guns on ships I always see the brass being spewed into the ocean! Why not have a catcher bag? The money wasted isn’t that much but it’s still money being wasted.

Steven Alfred Rake

I do agree this is a good system but with the fleet operating 4.5 inch and 5 inch along with 57mm, 40mm and 30mm for the next 20 odd years or until the older systems are retired there is going to be even more logistical burden put on the RFA who are struggling to keep up with the very limited resources they have at the moment.


I am or was one of the ones that argued about the 5in gun of the T26 and the 57mm of the T31 and possibly that they should be swapped over. However, looking at what the T31 is designed to do I have come to the thinking that the 57mm is a good gun for the task expected. I would though like to see some improvements in the weapons fit of the T31 in the future. For example I think we could all agree that when it becomes finacially possible the missile fit should be 24-36 Sea Ceptors plus 8 anti ship missiles. I have an issue with the aft mounted 40mm gun on the T31 as it looks like there will be no below deck magazine.So to overcome this I propose the purchase of five extra 40mm gun mounts and place them on the corners of the hanger where the 30mm guns would go. That then means the 40mm would have a magazine, with two 40mm firing aft or two 40mm + the 57mm on a broadside. Where the current aft postion of the 40mm being replaced with Sea RAM. The 30mm with LMM could go midships. That would give the T31 multiple layers of engagement with Sea Ceptor, SeaRAM (11 missile version with intergrated sensor suite) and possibly the NSM for anti ship. Guns would be one 57mm, three 40 mm and two 30mm with LMM/Starstreak mounts. Smaller point defence could be two GAU-18B .50 cal gatling guns and four 7.62 miniguns. Yes I know it will cost money, the highest cost would be for the NSM which would come in at £72 million for the five ships plus £1.8 extra missile. I would expect that these additions to be between £30-40 million per ship and could be undertaking during a refit. With this extra investment into what is a good hull the T31 could become a very powerful independent command general purpose frigate.


But they are not going to do work that needs this level of armaments. The RN has far more pressing priorities than spending £200/300m plus ongoing extra crew and training costs on a class which the HMG wants used for patrol work in medium risk areas.
I would be nice if all escort sized ships were able to do “high end” work, but there is nowhere near the budget. The RN is now very much a high end, often carrier based task group for potential combat and a world wide patrol/presence force and no more. If there was a big increase in naval budgets this could change, but there’s no sign of that.


Hi ATH. I agree with you in many ways yet at the same time I disagree. Yes the T31 is designed for a low threat area; however, in times of war ships are not always in the right place at the right time. Very often they will be sent on duty that they are not designed for. I have often argued and will continue to argue that a warship needs to be equipped for war the moment they go on patrol. They cannot just run back to base and pick up some extra kit. It takes time to install new kit, it takes time to build kit, and we don’t have the ship numbers to have some ships in refit for six months in times of war. They need to be ready now.
I understand the cost constraints put on the fit out of the T31, and in my personal opinion the MoD and the RN have got a good ship hull for the money spent. I will assume that the T31s will go into a major refit after about five years of service. If that is the case then the MoD could buy one year five extra 40mm mounts. The second year five SeaRAM mounts. The third year NSM missiles and fittings and so on. Then by the time of the first major refits all the bits are available. As for extra crew, as most of these systems are automatic I would think it might mean an extra 10-15 tiffies per ship which is surly doable.
The main advantage with these future upgrades would be that the T31 if called apon could act as close guard ship to the carrier or and RFA support ship in a carrier task group. They would be able to operate as convoy escort for the US reinforcement of Europe. As well as an independent command in medium threat areas or (my wish) flotilla leader of a fast attack missle boat group (two Hamina type boats and one T31) to operate as a group in the Persian Gulf, Red Sea, English Channel, Malacca Straits etc. The ten Hamina type boats could replace the P2000 class. If we could get this type of boat and possible a one for one replacement then the extra six boats could be used to escort pesty Russian ship in the Channel or of the West of Scotland protecting the sub base. That would release our frigates and destroyers to do the job they were designed to operate in the deep blue. Yes again I am well aware that to build 16 of these types of boats would cost about £2 billion, yet it would give 16 extra towed arrays, 128 Sea Ceptors, 64 anti ship missiles out to a range of 400km and a radar coverage surface of about 321,700kmsq. Oh I forgot the anti sub torps.
So by spreading the investment over five years it would cost about £50 million per year so that should be possible. What should also be remembered is the issue with the aft 40mm it will have no below deck magazine which means it would fire off its ready use ammo in about 30 seconds. My idea would mean a full magazine capability. Again I understand money,money,money. but with some out of the box thinking we could get a much more effective fighting navy.


This is pure fantasy.
The RN has changed. It’s now a combat force and a patrol/presence force. The later are not going to play much part in first line combat. The experience of using kit like the snatch LandRover in Afghanistan will have put the MoD off using inappropriate kit in combat. They would need far more than a few weapons systems to upgrade them. You could easily blow another £1B on upgrades to the T31.
Most likely what will happen is the ships will head off as built for 10 years (with a light 5y check/refit) down route. After that who knows.

Meirion x

A 5 inch gun on the T26, will be capable of firing mini depth charge rounds, which is what is needed by a ASW vessel.
Handy if a sub comes closer than expected, like with HMS Northumberland 18 months ago.

Last edited 2 years ago by Meirion x

I am surprised the article do not talk about the lack of tracking radar for the 57mm and the 40mm in Type 31. Without that they large OPV’s.


The prerequisite for the CIWS of the Bofors Gun is that it relies on the main radar, which is larger and more detailed than the small and small independent radar of the Phalanx, and is capable of more detailed radar beamforming.
And you won’t be able to hear the detailed story anywhere.
However, since performance has been proven in RN, only the fact that it is more advantageous than the Phalunx should be treated as an open story.


T31 have a rotating radar, it can’t track an enemy missile permanently like a tracking radar. A subsonic missile travels 300m in 1 sec. a supersonic missile 600m.


Even a rotating radar can track penetrating missiles,

Radar calculates how far away an object is from the radar and at what speed it is approaching by transmitting electromagnetic waves that bounce off an object and return. Of course, it may be good to continuously irradiate high-power electromagnetic waves like the AESA method of a fixed panel – American ship, but in this case, the function such as a guide of the Bofors gun may be insufficient.

Methods such as Type 31 and Type 45, which emit multiple frequencies alternately in rotation at the center of the hull, each have their pros and cons.

For NS100, use E/F -band
Although more computations are required than the Phalanx, radars made with GANs are more durable and allow for more continuous emission.

In addition to that, it is possible to calculate multiple variables more precisely and in a faster time by utilizing the ship’s huge operator resources than the small and small Phalanx main board.

= Better than the phalanx.


A better option for T31 is probably to add a NS50 radar as secondary. It can act as a dedicated fire control radar or take over from the NS100 if required. ie while it normally turns, they are adding the ability to stop & stare.


The ‘lite’ ie non-deck piercing versions of this could presumably be retrofitted to the River class OPVs if funding became available ?

Ryan Brewis

Stupid question probably, but what would be the odds/potential benefit of making the 57mm the standard “light gun” so to speak? Replacing the DS30M and maybe even Phalanx too on the Rivers, T23/45 etc. Might add a bit extra bite to RN ships and offer better AA/ASuW protection than 30mm+20mm or is there issues with weight, positioning and so on?

Just Me

Bofors Mk4 has that role


So why was this chosen over the OTO Melara 76mm SR?
Was there a UK competitive evaluation, and if so, what were the findings?

I get that the rate of fire is higher, but what with a longer range and guided munitions, I would have thought that was less of an issue.

It would (I presume) also be more suitable for engaging other ships (not that I think any naval gun will ever actually be used against ships (larger than fast boats) ever again… Missiles just have so much greater range) and for NGFS.

Mr Bell

I wonder if there is any benefit in having a specialised surface warfare/ land strike version of the type 31s- say 3 more hulls- equipped with 2x mark 8 4.5inch guns handed down from type 23s and NSM’s or a small mk41 vls with tomahawk/ LRASM? these ships could be fitted with sea ceptor and say 4x 40mm bofors guns so highly specialised in close range air defence and optimised for naval gunfire support/ patrol duties.