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Bill Crozier

Last 40/60 went out in the noughties with Orwell. Admittedly a mk3


Basically an admittance that they got it r’s about tit when making the decision to drop the 40mm in the first place – never do they get it right!


Not really. 40mms were dropped because chucking out a low volume of larger shells wasn’t as effective as a high volume of tungsten.

The advent of intelligent ammunition has changed the equation, such that bigger calibres offer more advantages again.

Supportive Bloke

Also accuracy of fire control is orders of magnitude better.

You can put rounds exactly where you want them.


Not really. 40mms were dropped because chucking out a low volume of larger shells wasn’t as effective as a high volume of tungsten.

Royal Navy got a missile fetish, that is the only reason to have dropped 40mm and otehr guns , because of that dozen of sailors died in Falklands.

Supportive Bloke

We have argued this out here abs on UKDJ a few times.

Manually aimed cannons are not effective at planes that are approaching the sound barrier. They have no CIWS use, other than luck, against munitions.

We have also been over the fire control systems a large number of times. You state that monopulse radar existed. Yes, Phalanx, and it’s ilk did exist but were uselessly unreliable until the ‘90’s.

Phalanx actually wasn’t very good accuracy wise which is why the ‘cone of metal’ approach was taken. But is was good enough that metal would hit incoming a high percentage if the time. It worked – eventually – it was a viable IDEA.

If you tried the same thing with cannon, with dumb ammunition, it doesn’t work as the shot has to be spot on.

The bit you don’t appear to accept is that obtaining a precise **predicted** firing solution for a cannon on a platform that is moving in 3D is quite complex. Doing the same thing from a land mounted cannon is much easier as, hopefully, the land is a not moving – only the target.

It was tried, if I am remembering well, to connect the Sea Wolf to a cannon system. This worked OK but switching backwards and forwards from controlling missiles to guns was problematic. It kept locking up the interfaces.

I need hardly say that full fat Wolf couldn’t fit on things like T21 anyway but that was the kind of computational power needed to aim the guns ** at the time**

Now, of course, you can do the calculations on any microblade server.


In WW2 Kamikazes were killed by AA, there even reports that an HS293 was.

Explain how high subsonic SSM can be hit but much bigger aircraft don’t…

…why everyone had anti-aircraft guns in their ships in 70’s and begin of 80’s except RN.
France : 100mm
Dutch: 76 Oto+Goalkeeper
Germans: 76 Oto
Spain: 76 Oto + Meroka
Italy:76 Oto+ Double 40mm Breda
USA: Phalanx
Scandinavians: variations of Bofors and 76 Oto.
Soviets: 6 barreled CIWS+ 57mm+ 76mm +100mm.

Were they all dumb?

…and why RN invested in Phalanx and Goalkeeper after Falklands…

And how an A-4 loaded with bombs and at sea level can approach sound barrier?

Supportive Bloke

As I keep explaining Phalanx wasn’t a working solution until well after the Falklands.

Neither was Goalkeeper.

Throwing lead around in the hope of hitting stuff is totally different to precision delivery of munitions.

I suggest you find a decent book on naval gunnery.


You explain nothing. Explain why almost all countries had gun radar AA in 70’s?

I suggest you look at 2nd world war naval AA.

Supportive Bloke

This conversation is pointless.

You don’t understand how the baseline parameters shifted over time.

Comparing WWII tech to ’82 tech to modern tech is apples, pineapples and orange stuff.

Many countries put useless weapons on their ships, and elsewhere, to give an impression of firepower. Sometimes simply because ‘they have some of those and they look impressive’.

Have a look at:-

In most types it spells out the limited rates of training and elevation speeds and these are shown. This is why they a of limited value against faster and more agile targets.

The main lesson ’82 was ditch the fig leaf weapons and concentrate on the ones that really work.

This stuff was extensively re-tested in the late ’80’s. It was pretty useless.

You do realise that the vintage stuff wasn’t gyro stabilised right? I mean some of the **gun sighs** were but the gun itself wasn’t. So they are just randomly hurling lead in the vague direction of the threat.

The new vintage 40mm and other weapons like Phalanx are gyro stabilised.

On the other hand Sea Wolf was the correct solution it was just in its infancy in ’82 so got a bad press which was really unjustified as it performed very well when paired with the pulsed Doppler radars that sent down South.

In contrast to all of that land hand radar laid 40mm, or similar, cannons did work pretty well. And I would agree that some 40mm, or similar, land radar laid AA batteries on the peaks would have been more than very useful in defending bomb alley and would at the very least have made low level tactics too hazardous.

There is a decent article here

that goes through the current CIWS options.

Happy reading.


The baseline is just an increase of 200-300kph in speed from WW2. Nothing that computerisation advantages of 70 could not improve from 40 systems, besides the higher rate of fire. No 76mm 3″ in WW2 could do could only do 12-15 rpm not 80-120 rpm with radar fuze.
In Ww2 a 40mm Bofors had an impact time fuze.
In 1970 it could have a radar fuze besides increasing the rpm to 300 per tube.

Since you defend everyone else is stupid except RN tell me how even naval based manual crewed 20mm Oerlikon in Falklands hit Argentinian aircraft ?


I’m sure we were using radar proximity fuses against V1 rockets and kamikaze in 1944 and 1945 respectively. We needed HMS Vanguard (1946) to sort the Falklands.

Supportive Bloke

Yes, they were.

It is gone into in detail in R V Jones’ ‘Most Secret War’

Supportive Bloke

The ‘computers’ used to run the 40mm cannon in the ‘50’s were all valve analogue. They worked great provided the temperature didn’t change or anything and they were ‘accurate’ in a narrow central range. It also ‘drifted off’ over time.

The 1970’s computers you cheerfully refer to filled a room – look at Dart and Wolf control systems they were massive. Computers then were painfully slow by todays standards.

There were radar fused shells for 4.5” guns….

Sometimes if you throw enough lead around statistics and luck fall to your side?


40mm holds 1100 tungsten balls, id say that is high volume from a rapid firing gun(or pair)

Max Jones

These are essentially 40mm CIWS. Not the same as a battery of 40mm guns firing aimlessly at air targets within a few kilometres of the aircraft.

If enemy aircraft are getting that close now it’s a pretty bad sign all around.


In Type 31 they are not, They have only EO tracking. In fog they are blind.

James Fennell

Not true, like Sea Ceptor they can be cued by the ship’s radar via the Combat System (its in the article)

Last edited 2 years ago by James Fennell

But its accuracy will be limited. If not, there is no need to add EO FCS system.

3P needs good location and distance information. As NS100 cannot provide accurate enough information to “fully utilize” 40 mm/57 mm guns’s capability, EO FCS is added. Logical thinking, I think?

Last edited 2 years ago by donald_of_tokyo
Rob N

I do not think that is true, the EO is there to provide an extra channel of targeting. The radar is good and can cue the programable ammunition that can do the rest. It is likely there will be sensor fusion between the radar and EO making an accurate picture all the weapons can use.

I think we should ditch Phalanx and 30mm and just fit these 40mm this would get the job done and rationalise supply chains….


Simple question. NS100 is rotating, so it covers 360 degree. If NS100 can do it, there will be no need for “additional channel” of FCS?

Or the EO is there only to identify the “friend or foe” by man-in-the-loop?

Supportive Bloke

Yes. I agree.

Someone else we, all love, keeps repeating the same thing about them being EO only.

Rob N

Not EO only… radar too..

I think the NS100 also has a built in EO scan system too.

EO is great for identification…. it has also been used to enhance low level target acquisition against cluttered seas as in Phalanx 1B. You can also use laser ranging to get very accurate distance to target. Also EO can see radar stealthy targets too.

However with newer radars AESA the radar is very accurate to and can provide enough data for gun systems.

The truth is that radar and EO are complimentary…


EO can do the tracking even searching. I am sure the sensor there can detect differential, contrast etc movement.
But if it is bad weather its range is very diminished. So the guns can only fire based on search radar cues. But the search radar since it is rotating have not the same precision(frequency for more range) and temporal accuracy as a dedicated radar director.

I believe that Type 31 was mostly created as a ship to fight boat swarming. The return of gun boat diplomacy…

Rob N

Yes a F/C radar would give dedicated targeting but only to 1 or 2 targets at once. The T31 rotates a 60 rpm once a second, plus it has got electronic beam forming/directing so the radar can linger on a target tracking it.

So there is little doubt that the T31 guns will have enough data for accurate gunnery.

The T31 is a general frigate and can do many tasks. It is also a hull with big growth potential. You could add more SAMs, ASM etc….

Supportive Bloke

Yes my comment agrees with you.

All of the 30 and 40mm that RN fits can be integrated into the CMS and probably are.

Somebody we all love pops up every time I say this and flatly says they are not.

Unless he has looked at the wiring, Ethernet cables, himself he cannot possibly know that. Given that it is about the cheapest upgrade you could make to the system that would increase its usefulness about x100 and probably uses weapons software modules that already exist then I’d be amazed if it was not done.


You also need redundancy. A turning radar has the addition of mechanical factors which can bring it undone on top of the electronics. Even a small hit (like from a 57mm) in the right place could be enough to take out the main radar. Without radar you have no missiles & the guns will need EOS otherwise you are defenceless. It is also very hard to jamb an EOS system.

David Broome

They have to be magazine fed. If not, each weapon has just 20 seconds of full rate fire. That is just not enough for a swarm attack.


Well they prob won’t be magazine fed then lol, how many rounds can a magazine hold? And can they change between diferent rounds quickly, like the 30mm should also have double magazine fed for diferent round choice.

Rob N

The point of a programmable round is that you do not need to change between round types… you tell the round what sort of sound it is….


Ok fair enough buddy


A little confused by the concern about missile defence, is that not the prerogative of Sea Ceptor? At least until there are none left. Note vessel is only doing the Constabulary Role, it is not designed for high intensity warfare. Sea Ceptor, 57mm, and 2x40mm seems a reasonable start.


I’d say it’s part of the principle of layered defence that the Royal Navy has taken pretty seriously since The Falklands. Sea Ceptor can be used to remove threats at arms length but you still want an effective way of throwing up accurate/effective fire as a final barrier if the missile silo’s are empty or anything hostile gets through.


The Royal Canadian Navy is going ham and using Sea Ceptor as the last line of defence on the CSC T26. SM2 to ESSM to SeaCeptor to 25mm. Crazy.

Alpaca on shore

That said, there is always an option to bolt on some Phalanx mounts last minute.

Supportive Bloke

There is a, quite big, common stockpile of Phalanx that can be bolted onto whatever platforms need them.

Being self-contained, one of Phalanx’s key selling points is being non-deck penetrating – it can simply be bolted to the deck of any ship with space and top weight margin.”

“Through a rolling procurement programme, the RN had accumulated 36 mounts by 2001 which comprised a mix of Block 1 (Baseline 2) and Block 1A. In 2006 Babcock were awarded a £35 million contract to convert 16 of these mounts to B1B standard, using kits supplied by Raytheon. Subsequently, an additional 8 units were upgraded and in 2012 a further 5 new B1B mounts were purchased directly from Raytheon, primarily intended for RFAs. In 2014 Babcock received a contract to upgrade a further 4 units. There are at least now 41 mounts in the RN inventory and at least 33 of them are B1B standard. Units are rotated between warships in refit and RFAs not deploying to high threat areas, providing for planned maintenance, as the table above indicates, there are sufficient numbers for the RNs requirements.”



The removable feature seems to be a big plus

Supportive Bloke

Mmme but why do ships in deep refit need Phalanx?

Rob N

Have the 1Bs been upgraded to 1B baseline 2 with the AESA f/c radar?


Canada loads of money mate, not like the UK on a shoestring, keep on dreaming.


Canada doesnt have anything like what the Royal navy currently has…


Quality not cheap under gun quantity mate, come up with the money.

Last edited 2 years ago by Harry
Jim Camm

Canada’s navy thus far consists of 4 rather nice Upholder class diesel-electric subs from the early ’90s and a dozen purely ASW frigates.

They’re only buying 1 class of ship so they can afford to splash out and give that 1 class all the bells and whistles. They don’t have to fund a fleet of nuclear fleet subs and ballistic missile subs, aircraft carriers, planes and a larger array of escorts, patrol ships & support ships.


The guns are primarily for drones and light surface vessels
leaves the missiles for other incoming missiles or aircraft


You could imagine that in future, there could be other targets, like swarms of cheap drones/missiles, that you couldnt/wouldnt want to waste valuable sea ceptors on.

Rob N

Thats why they are working on directed energy weapones.


I’m guessing the Bofors 40mm Mk4 isn’t that expensive if it’s been selected for the T31? Going back to it is effectively an admission that the Royal Navy was wrong to move away from larger caliber systems and standardize on the 30mm all those years ago.

Would be good to see more progressively purchased to replace the DS30M systems on all of our major surface vessels. The latter type could perhaps then replace the remaining 20mm mounts on things like the Echo’s and some of the RFA’s to consolidate down to fewer types and give everything a bit more punch!

I also fail to quite see the need for a CIWS like Phalanx if we could role out more of these.


Standardization brings its own benefits in training, maintenance, spares holdings etc. Replace all remaining Mk8 4.5 on T45 with the 57mm, and all the Phalanx with the 40mm ???

I mean if money was no object (yes, I know, stop laughing) I would upgrade Phalanx to SeaRAM for all RFA’s …… 🙂

Andrew Wilde

All RFA,s, as with the latest Royal Navy warships, are fitted for but not with the ‘latest’ means of defence against incoming hypersonic missiles. There appear to be six sets of Phalanx between six RFA,s. Remember the good old days when the Leander class frigates appeared with two 40mm on top of the hangar because there was nothing else available until the world-beating Seacat would appear!!! Just how long did it take from conception to scrapping, decades during which every other Navy bought superior kit from the Russians or Americans. Then along came Seaslug. Join the Royal Navy and watch the world pass you bye.


Oh my god that’s hysterical! Well, those WWII 40’s were probably more effective than than “the Cat” ? My first ship was an Exocet – Sea Wolf Leander (HMS Hermione) which despite the world beating(!) GWS25 suddenly sprouted 3 GAMB-01 20mm before our Gulf deployment,you know, just in case….. oh yeah and very early laser dazzlers……
As for Exocet, I mean that new 40mm probably has longer range…… 🙂


The Rocket Exocet was a bit short legged. The jet ones of today offer similar range to Harpoon.


CWIS Phalanx against hypersonic missiles? Keep on F&#king dreaming!
Like trying Seaslug to shoot at Exccet.

Last edited 2 years ago by Harry

Sorry, can you write that again please, I’m not quite with you regarding the first sentence ?



Last edited 2 years ago by Harry
Rob N

I do not know why people go on about SeaRam, Sea Ceptor is much better…. SeaRam is old… However I agree that they should replace Phalanx on T45 with these 40mms. Also replace the 4.5 with the 57mm. You would never use a T45 forNGS so you are better off with the 57mm that can do CIWS mode too.


So does anyone know from public open source materials if the NS100 spin / scan rate, can feed the combat system with high enough frequency of updates on target position, course and speed to consider the guns on a T31 as an actual anti-missile CIWS? I presume a supersonic AShM is going to have a fairly bright IR signature due to airframe friction heating, so presenting a good target for the EO turrets IR sensors, but can they get a good target lock? Personal experience is with video tracker on GWS25 (Sea Wolf) over 30 years ago(!). Bottom line – is this really a CIWS, or an anti-small swarm weapon?


It will not be good as a proper tracking radar. And in fog you are dead if the 40mm is the last resort to pass.

Rob N

It does 60rpm. It can be used for CIWS.


In 1 second a subsonic missile does 300m. And that is not accounting for the increased precision error due to not ideal frequency of a search radar.

Rob N

It is AESA with beam forming. The beams can be directed and locked onto a target. As a result of directing the beams at scute angles the time between dead time is reduced so in effect target update will probably be half a second… the 3P ammunition can fill a bracketed area with metal. So CIWS is possible.

Matt G

See above for specifications for the Mirador EOS. The NS110 mounted on the Inspirations won’t be too great for FC for quick short range air defence due to its rotating nature, so smaller radars and these EOS supplement it for all-around short-range coverage. The Mirador can scan for missiles or drones, and provides ‘short reaction time in multiple target scenarios’ as well as “high precision Fire Control against agile air and surface targets”. An option to equip a ‘low-light near infrared camera’ is also provided.

Last edited 2 years ago by Matt G

Bofors 40mm are a thing of joy.

Why didn’t the MoD try to navalise CT40? >smirk<


there is a navalised CT40


Um. Do you think I don’t know that…………..

CT40 is expensive and mechanically flawed………


Could we add them to the OPV’s also, at least in the non deck penetrating option?

Ivan The Non-Russian

Government finance dept. would then designate the OPV as a corvette and accordingly reduce the Navy’s budget for new frigates… not too good.
Good news is that this is an option for times of crisis, but it would need a deeper look at want you expect to get out of an OPV vessel, with its best use probably been a platform for a Merlin in ASW config. to guard areas around relevant naval bases.
In this config. having a bolt on 40mm offers it better self defence so long as it is kept under a local air protection.


40mm 3p ammunition has been around for 15 years, RN is always cheapskate in adapting new technologies

20mm/30mm CIWS are still very good against subsonic AShM but against supersonic/hypersonic AShM need to be stopped at longer distance to prevent debris damage.

The 3P pallet is too small to destroy AShM totally but rather aim to damage critical components, control surfaces, missile engine, electronics, wires.

30mm CIWS hit will destroy an AShM.
comment image

Last edited 2 years ago by Harry

Which is why, certainly partly responsible for the Italians using 76mm OM guns for the same purpose.

Perhaps a 76/57mm combination of guns might have been a better option for the T31 as others on here have previously posted. A more expensive solution then the current combo I know, so whilst it might have been looked at, probably wasn’t a good fit for the budget.


Its a huge jump in expense. I wish I still had the source which gave ball park figures but they were something like $60 mill for a 5 in gun. $30 mill for a 76 mm. The 40mm might be $15 mill


40mm on the OPVS would be great, and two 30mm on each side of bridge.


Why would you want to burden a patrol ship with maintaining all those guns? A 30mm is fine for pirates which is all the OPV’s are designed to fight. The Rivers are not light frigates for lots of reasons the least of which is the main armament.


Is it really that big of a burden? Being under armed is a bigger burden… and the Thais don’t seem to think it’s that big of a burden. And arming our far flung opvs properly shouldn’t be a burden it should be law… we never used to do it.


Is it really that big of a burden? Being under armed is a bigger burden IMO… and the Thais don’t seem to think it’s that big of a burden. And arming our far flung opvs properly shouldn’t be a burden it should be law… we never used to do it.


River B2 is laser focused on long sea-going days. Among the many assets RN has, none of them can beat River B2 on “sea-going days at ocean”. Adding more weapon will surely reduce this figure of merit.

Of course, there will be tasks needing more weapons. But, for tasks in Caribbean ocean and Falkland Islands, and many of the tasks in Med and west Africa does not need it.

As such, I prefer basic hull to be less armed, and some additional weapons be added if needed. LMM on 30mm turret may be an option, some NavyPODS with Brimstone or SPEAR3-like will be another option. Another idea is, uparm, say, two of the five River B2s, if 2 hulls are to be sent to high risk area.


In the last edition of Airgun World, there was an article on the merits of .177 and .22, the arguments are much the same truth be known, I’m a .177 fan personally ! Anyone know any decent Christmas Jokes about Special arctic Missions and Typhoons ? 🙂


Target shooting – .177 definately. Rat shooting .22

John S C Lewis

I am a .22 shooter. I tjust doesn’t seem right to shoot a .177 out of a rifle! ?


I remember the first time shooting a .22 and seeing the pellet all the way to the target, so disappointing !


2 things that don’t add up here and demonstrate once again a lack of joined up thinking in defence.

  1. Why did we not standardise on the CTA 40 which the UK has invested heavily in and supposedly has a much greater range of fires and kinetic effect / impact.
  2. The Barrel on the bofors will need changed after 17 mins of contiuous use at its maximum 300 rounds per minute, if said RN ship even has 5000 rounds available and if not why is this being presented as an AAW defence system by the RN
  3. Whilst I know the above is highly unlikely – this is against the CIWS which can fire 3000 round per minute and has 1500 rounds ready. In the event of a swarm attack it is not inconceivable that the Bofors will need to bring all its weight of fire to the situation.

there is nothing wrong with the gun itself, but with such a small military ruthless standardisation is required, instead we are adding new niche product when a perfectly good (albeit expensive) model is already in use in the Army (CTA 40 which has a nasalised version).

We should also look at the new 155mm guns and perhaps thinking outside the box , would a navalised boxer module that can slot into the deck not be ok for use on a T31.

Lastly – surely this calibre of gun is perfect for the River class – once again standardisation is key.


Interesting point with the River B2s. A 40mm would be very useful. For once thing any bad guys could actually see it and would know that it could hurt them at distance. Relocating the 30 mills behind the bridge also a good idea. I’m surprised at a tube launched version of Sea Venom isn’t lurking about. Put that on the very large flight deck of a B2 then it has some offensive capabilities. 75% of a frigate for not much money. I’m all for maximising the capabilities of these 2,000 ton vessels. Bigger than a WW2 Tribal.


Do any Royal Navy vessels carry hand held anti air/ craft weapons for last resort backup? Sure could have done with some in Falklands I know that much.

Supportive Bloke

If Royal or SF are on board it is possible.

There certainly are various shoulder launched in UK inventory.

There were Stingers down South in Corporate but SF had them.


Yeah no doubt. And wouldn’t it be handy for our ships to always have a dozen hand held anti air or anti material missiles..… doesn’t it make sense??, relatively cheap and we have thousands.. even something like javelin but maybe longer range.

Maybe our Overseas based OPVs could have a bunch of these hand held missiles?? If their 30mm is out of action should they have some kind of offensive backup?? Cheap and lethal hand held?…why not?? Also the opvs should all have martlet anyways.., again why not??

Supportive Bloke

Well someone has to be well trained to maintain and use them.

They are not just plug and pray.


Yeah but having crews train for a few days isn’t that big a hassle.

Rob N

Adding the T31 40mm would be good for B2 OPV. Perhaps ditch the 39m and add 2 miniguns. Also some Martel missiles….


Interesting points:

1 : CTA was deemed to be too expensive for day-by-day use, I guess. “Standardization” is important to make the overall operation cost small. As Bofors 40mm gun is still there worldwide, and its ammunition is produced elsewhere and thus cheap, selecting Bofors 40 mm is good in operational cost point of view, I think.

2/3 : Barrel life may be short for 40 mm, but I cannot understand it being a big problem. If it can fire 17 minutes long (of with 10% duty = very high rate, actually, it is 170 min equivalent), isn’t it long enough? Also, 40 mm Mk.4 will require less maintenance than 7-barrel high-speed rotating complex 20 mm Gatling system of Phalanx, I guess?

Idea of navalised boxer turret is interesting, but it all again rely on how CTA40 rounds could be cheap. In navy tasks, 40 mm guns’ tasks will include many cases of “law enforcement” type activity. “Warning shot” is frequently needed, and firing expensive CAT40 rounds in water might be not ideal, I guess?

On standardisation, yes, introduction of 40mm Bofors generates a problem, I agree. Actually, I was surprised, why not 30 mm + LMM? Of course, 40 mm 3P is better than 30 mm + LMM for countering fast boat. So, merit of 40 mm bofors prevails against commonality?


The CTA has a practice round that I guess could be used as a warning shot.

my main issue is we don’t seem committed to getting things standardised across the whole force, we should have a single turret on our land vehicles and perhaps should look at what a boxer module slot would give us on our new ships (perhaps nothing, but worth a look isn’t it).

CTA are testing 105mm rounds now and given the USA has developed the XM360 and XM35 guns that are much lighter than their predecessors but still high performing, perhaps we can match the lessons learned from both to create the next generation gun that can be used across the whole force.

what. Don’t like is having different products that basically do the same thing, which ultimately drive up cost.

latest example is the rangers getting a different rifle, with the only reason I can see is to make them look like SF.

these decisions should be done across the whole force so that once we have a calibre production inventory then we need to ensure we standardise on it and extract maximum value from the original decision. Clearly we are just not doing that at the moment which is disappointing when everyone complains about lack of money.

the French are very good at this in my opinion and whilst we have improved, this decision is not a good one if the army are standardising on CTA


With 5000 rounds each covering a 160m area of shrapnel with that ammunition you could essentially cover 800 cubic km in shrapnel.


Very good turret I think.

Although 3P round is great, but the system was there for decades. It is clear that its capability for ASM defense is not enough to replace Phalanx/Goalkeeper CIWS world-wide. It is capable but it is NOT necessarily better than Phalanx in anti-ASM role.

On the other hand, 40 mm 3P capability is surely better against fast boat swarm and (relatively slow moving) UAVs. In these days, countering suicide-drones and/or fast boat swarm/harassment becomes more important in the Middle East. Also, for full-level ASM defense, T31 has 12 CAMM.

So, I agree T31’s armament is sweet-spot for operation around Persian Gulf, Oman, Red Sea, and east Mediterranean.

The new Mk.4 turret looks smart, capable, and compact/light-weight. However, the ammunition will surely be expensive than that for 30 mm. For OPV’s task, “dull-and-cheap” rounds are very important, because 99% of the fire are warning shots. If it can be cheap, say, within a few times of a 30 mm dull-ammo, replacing 30 mm gun on OPVs with 40mm gun might be interesting.

Chuck Hill

US Coast Guard cutter, generally fire .50 cal. as warning shots, not their larger weapons.


Thanks. How does the UK RN OPVs? Do anybody know?


It has a maximum range of 12,500m, effective to about 10,000m.”

Nonsense!…again typical Bofors exaggeration……12.5km is max BALLISTIC range at 45° elevation. Effective range is not anywhere close to 10.000m either, but rather 4-5km against large surface targets.

” It is only sufficiently accurate in the CIWS role to engage missile targets at around 2.5km”

40mm 3P doesn’t have neither the Pk nor the lethality to be effective against anti-ship missiles, and certainly not of the heavy russian/chinese types.
The large number of smaller fragments produced py 3P results in a denser spread ( though 140m2 is again wildly optimistic) but also one which lacks the mass and kinetic energy to seriously damage AShM’s or larger aircrafts.

3Ps primary targets are smaller surface crafts, UAVs and light unarmored helicopters against which it is reasonably effective.


The Type 45 still carry the Oerlikon 30mm with its 500+ rpm which is very impressive in operation, perhaps better in AA than the 40mm.


It is a question of radar control or not.


Nonsense!…again typical Bofors exaggeration……12.5km is max BALLISTIC range at 45° elevation. Effective range is not anywhere close to 10.000m either, but rather 4-5km against large surface targets.



40mm Bofors can shot down Anti-ship missiles including Russian/Chinese Missiles. If 3P is insufficient (1 shell would be but several would wreck flight control surfaces etc) then 40mm APFSDS can be fired. In the Twin Compact Mounts from Oto Melara they had a 500 round magazine of PFHE and a 200 round second mag filled with APFSDS which was switched to when the target got within 1000meters. APFSDS most definitely could kill a P700 Granit AKA Shipwreck under Nato naming. Effective CIWS range is 3km with PFHE and 3P should be just a little more. Oto Melara now Leonardo does make a Single Fast forty (Fast forty mod increases ROF from 300 to 450PRM per gun) with 2x 72 round magazines with options for Remote Control, Manual Control +Remote and the C model with its own Micro Fire control system plus remote control

Supportive Bloke

The reality is that you are not going to rely on one single 40mm shell to save the ship.

You are going to fire a reverse path of shrapnel into the ship that the missile will fly through being progressively degraded and shredded.


yes, the 35mm Millennium gun with AHEAD ammunition does the same thing but with a time fuse (uses a muzzle radar along with data from the system that the CIWS is linked to either Radar or IRST…Millennium gun was designed to be open architecture for this reason to allow the use of as many sensor systems as possible). Basically forces the missile to collide with many many tungsten fragments – supersonic missiles have it even worse as their own velocity makes these fragments even more lethal

Rob N

The T32 has a 57mm too with 3P amo. The 3P cam be programmed for hard targets…


That’s some very impressive weight saving- 40-60% less than a Phalanx depending how you read that last paragraph!
All in all I’m happy with the selection of the Bofors, although I’d been hoping for the CTAS 40 and also that there might be an opportunity to strap some LMM to the same mount (doesn’t look like it from the images on this article).


All it needs now is a couple 30mm midship!! But it’ll prob get 50 cals yeah? If so how many?

Armchair Admiral

I suppose it depends on what benefit you see the 30mm bringing to a 40/57mm setup rather than having a 50cal.
For my money and partly from the standpoint that we have them, I would like to see a pair of 30mm fitted. I also like that they can operate as stand-alone mounts for when main power is down or some such disaster. They also provide a much heavier and longer ranged punch viz a 50.
There is a maintenance and manning downside of course, as well as costs for ammunition etc, and this may be the main driver as opposed to fitting a few manual 50s.
It might be nice to have some RWS with 50 cal, but some might see this as neither as good as a 30, and more expensive than a few manual mounts.



Last edited 2 years ago by Cammy

Yeah, but maybe the 30mm would be a cheaper option in lots of scenarios to use than the 40mm and we have a Shi£ load of 30mm guns and maintenance/ equipment crews and spares, also two 30s each side midship with 8 martlets would be a great look for our under armed ships. But I take it the RN isn’t going to have ship mounted Martlet missiles…


Martlet Missile

Armchair Admiral

Cammy. I am not disagreeing with you At all. I would love to see a pair of 30mm and Martlet either side. The ship will presumably be carrying Martlet for the chopper so there will be storage for them.
You would have thought that the missile would/could be useful, being laser guided and proximity fused with a warhead much bigger than that on a 40mm or 57mm round.
Fitting something readily available like this would seem to be a no brainer.


Will the Merlins ever carry Martlets?? I Would love to see Martlet wings on our commando Merlins along with the 25 commando Merlins painted back to the junglie scheme or even to Dark green as any5hung better than the drab grey thst makes them look dirty permenantly unfortunately I can’t see it!!!…..

Last edited 2 years ago by Cammy





This greens far better than RN grey, and doesn’t it make Merlins,ok far better and mean business.. also do they keep them all grey now to make it look like we have more!!

The commandos got all the RAF Merlins and now they’ve all been upgraded and that’s great and a huge upgrade but they only got 25, how many seakings did that replace? And did the RAF take a huge chop in chopper numbers losing Merlins yeah? Or they get more chinooks?. and couldn’t new merlins replace the ageing Pumas? If not why not?

Last edited 2 years ago by Cammy

Black commando Merlins would look amazing


Merlin (which replaced Wessex go figure) is too big to replace Puma. They want a smaller cab for use in more enclosed spaces like the urban environment. I will laugh my cock off when they eventually get Blackhawk after all those ‘the AAC can’t have Blackhawk it is too big’ arguments of a few years back. With today’s UK military being so small it doesn’t matter about which colour of uniform drives it I suppose. I tend to see Chinook as the last link in the fixed wing logistic chain that can also do other things.


Not quite correct. The WG.34 was designed as a Sea King replacement, which is what you probably meant, but with 3 engines and ‘similar’ size


No. Not for the RAF……………….


WG.34 Sea King replacement
The RAF Merlin had rear loading ramp etc for a much bigger helicopter than their Wessex twin engine, which was in practice replaced by Sea King HC.2 or 4


Don’t you think wildcats a little small..


Not for the Royal Navy. Too big for the Army perhaps. But commonality and economy of scale count for a lot.


No F$%king money mate, no even twice 30mm on each side.


The thing is we do have money, but we need to spend it in the right places… we spend tens of billions yearly on defence….


yeah, money to buy F-35? money to buy submarines? money to buy tanks? where is the money mate?


Plenty of money. Our >cough< government chooses to spend it elsewhere…….
comment image


It is for the democratic elected government of the day to see fit how to spend tax payers money


And did I say anything different to that? No I don’t think I did.


I believe there were backblast issues with this arrangement and it was not pursued

Armchair Admiral

That would not seem to be such an issue on a T31 if the mounts were placed on the hangar, as there does not seem to be much around to get blasted.
On the T23 it is much more congested.
The question is, did the “on mount” martlet bring anything extra to the fight, blast issues aside). As a guided missile I would have thought so, but does it’s anti-air performance over the 57mm warrant the extra hassle? However, It’s an extra channel of fire on the stern arc, and if only 12 Sea Ceptors are fitted, then another 10 guided missiles sounds like a good deal…

Rob N

It may or may not have 12, it is possible it may have 24. Images for both have been seen. 24 would be great as that would add to fleet area defence and give the ship some extra combat persistence.


Why not put martlet on..


The RN was looking hard at the Oto Fast 40 in the 70’s for close in air defence before it got fixated on the never happened ‘lightweight Sea Wolf’.
Moving smartly onwards and a few sunken ships later, it panic bought 30mm mounts not because they were good, but because top weight on the T42’s was so marginal, it was all they could carry.


Struggling at why people think of stove pipes, why are the 40’s pigeon holed in the CWIS bracket, why use 40 when you’ve got 57, it’s about options, the new world is not about top trumps style warfare but about simultaneous threats from cheap asymmetric through to higher end threats and being able to manage complex simultaneous threats, you want options, what does a 45 do against a cheap drone providing ti sitting at three miles?

BM Lever

A couple of fundamental points if I may:

The 40mm round carries a much-too-lightweight projectile to stop a missile because the requirement for such a kill is a minimum residual kinetic energy force of circa 0.98 kJ/mm2 arriving in the warhead to detonate it – and that is after the projectile/shrapnel has completed it’s transit through the missile fuselage, and also perhaps elements of the guidance electronics & flight control mechanisms, plus the warhead casing itself. (The actual required kinetic energy figure depends on the sensitivity of the explosive in the warhead) Consideration also needs to be given to the angle of impact and thus the potential for the deflection of shrapnel/balls/tiles etc.

Neither the quantity of the explosive disruptive contained in a 40mm projectile in an adjacent air-burst, nor the effective mass of the expanding circle of the fragmentation/balls/tiles etc is significant enough to provide the requisite energy to detonate the missile warhead.

When such missile detonation does occur that is defined as a ‘hard-kill”
Detonation is the only way to terminate a missile – anything less than that is deemed to be a ‘soft kill’ and may well still allow the airframe/motor/warhead to continue on a ballistic trajectory and potentially impact the defended vessel; the steeper the terminal dive the more likely is overthrow. One has only to remember HMS Sheffield in the Falklands to see what a still-burning missile motor coming inboard can achieve (In that case, after a warhead failed).

It is only when solid DU (Depleted Uranium) and Tungsten – both of which have densities in the order of 18gcm3 – using sub-caliber penetrators, ie darts, in discarding sabots (APDS) are employed can a sufficient impact can be delivered into the warhead to achieve a lethality of 98% pK (probability of kill). This, in turn, requires a high degree of system accuracy (which is not in question here, but fin-stabilisation of the penetrator might also prove necessary), plus a sufficiently high rate of fire.

If it is felt that this approach restricts both the range of the projectile (due to the velocity decay inherent in the use of sabots), and also that the flexibility of the ammunition type for use in other roles is reduced, there may be a requirement for dual purpose explosive warheads, Conceivably this could be achieved by the use of shaped-charges instead of the solid tungsten (above) etc.. These are devices in which an explosive load is used to collapse a (usually metal) pointed cone-shaped liner, thereby instantaneously creating an extremely high velocity jet or slug of molten metal with a very high impulse density from it’s small cross sectional area. Such molten slugs are capable of penetrating deep into, or even through, metals and other materials. They would probably work well against high tech targets such as fixed wing aircaft, helicopters and patrol vessels – but less well against unsophisticated targets.

If ammunition manufacturers are so convinced that their ordnance is lethal enough to destroy (and disperse) a high-speed missile in a steep terminal dive can we please see video of such demonstration firings from an afloat platform against live missile, similar to those produced some years ago for the CIWS first-of-a class firings against the Vulcan Phalanx. Anything less is just theory – and we all know how dangerous that can be!


Great article

I am one of those who demand cross service commonality, and therefore can’t understand why CTA 40 wasn’t selected – especially since we already own a load of them + UK based Ammo factory.

One other area of consideration, does the RN have the right guns on the right vessels.

Surely T26 is better having this fit out as an escort, whilst T31 is more likely to be put in a position to use a 5in gun. (perhaps T32 gets the 5in)

Its an interesting conundrum and one that can still be remedied if the tasking briefs are updated or changed.

going forward – the AAW destroyers definitely do not need 5in guns and something similar to this is ideal

T31 is looking good imo.