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I suspect the minimum they’ll receive is Martlet on the 30mm. That’s what Cdr FPS was hinting at.

Captin Nemo

Oh no, I remember the T31 equipment thread.
Brace for impact.

Bow to stern I’ll say 40mm, Spike NLOS, 30mm/LMM, containerized 120mm, drones.


I’d go for the 57mm, Martlet, radar upgrade, the RWUAW and decoy launchers. Because its likely operating inshore or out to 200 mile EEZ, some mine warfare drone or multipurpose equivalent might be a useful addition should circumstances require.


I believe Sir Humphrey will say never over my dead body!


Include modular facilities for the Royal Corps of PR Specialists and Photographers and he’ll be fine.


Best upgrade a river could get is a platoon of royal marines.

Anything else a complete waste of time.


The Batch II have accomadation for 50 marines plus kit, they can at a push carry 90 but they need camp beds.


HMS Forth already carries 50 troop, last week.


Problem is the 30mm is not a good option at supporting troops ashore. Fine if you are a 30-40m PB. Not so good if you are a 90m 2,000t ship. You start to become a very big target. As the Falklands war showed, operating 1,000+t ships close to shore is not a good idea if the opposition has anti-armour or artillery weapons. The RGP is almost as common as the AK47 (it was a RM Carl Gustav in the Falklands war).

As to mention in the article of manually aimed 20mm & GPMG (excellent article by the way) on the B1’s. I would point out that PNG PPB mk 1 (30.5m 162t patrol boat) has similar armament. The replacement PPB mk 2 (Gardian class – 39.5m with ability to go to 30mm now being delivered).

Unfortunately, as indicated in the article, basic ASHM & other weapons are now starting to appear (& be used) in places no one expected a decade or 2 ago. The world has changed, yet again. There are mortars that can out range a 30mm. (& nothing a 30mm can do about it).


All depends on what Capability Update Margin and through-life growth margin they were provided with. All the “survivability” features referred to earlier, were not done to enhance survivability, they were done to allow the ship to meet Naval Ship safety certification under the NATO ship code. I suspect that meeting those requirements was not without it’s challenges, which means that provision for Capability Updates or through life growth may (I say again, may) be limited.

So, before we compare what’s been done to Brazilian or Thai ships, we need to understand that they are almost certainly operated under very different stability standards to the RN. Which may well preclude nailing all sorts of gizzits to the River B2s. Always remember that they were procured under the obligations of ToBA to provide work for BAES steel trades – which meant that they were what was available with minimal redesign. They were not designed from the off with RN requirements in mind.

Steve Taylor

And what are the RN’s requirements?

I often wondered why we ‘acquired’ B1’s without flight decks. I can’t see any need to base a helicopter on one. But just having somewhere to land on, drop stores, or winch off would have been useful. Yes I know it adds requirements for fire fighting etc. But one of the design drivers for the Castles was a flight deck because the helicopter in today’s marine environment the helicopter is important. Yet it was ditched.

The whole design is very conservative. Much the same could be done on 1000 tons.


Don’t forget that River B1 was VT (as was) clever plan to make the RN/MoD an offer it couldn’t refuse to replace the Island class, not so much the Castles (that was Clyde). As such they did the job admirably.

Primary tasking is for Fishery protection – for which no flightdeck is required. The FIPV does need a flightdeck for operations with the deployed helo flight at MPA.

The RNs requirements are both capability (ie sensors, weapons, boats, stuff etc) and safety (compliance with the NATO ship code). The latter cover (among other things) stability, structural strength, fire protection, escape and evacuation, manoeuvring and control and so forth. Those latter requirements will be very different to the Trinidad and Tobago coastguard (original customer for River B2), Brazilian navy or Thai navy.

Steve Taylor

Yes I agree for FPS a flight deck isn’t needed. But seeing the reasons why the Castles were procured with one then perhaps the B1’s should have had one too? Was not the plan to replace all the Islands with Castles? The helicopter is nearly as important at sea at the ship. It didn’t need designing and the cost of the steel as part of the whole couldn’t have been that much more to add some extra utility.

Your last line is what I need some help with please,

“They were not designed from the off with RN requirements in mind.”

How would an OPV designed to RN requirements differ? Size, engine fit out?

As I said in my original comment all of what the RN would want could be achieved in a ship half the size say,

I would even go as far as to say the Peacock class would do.

One will add that even though I am a disciple of St Barbara I am not interested into adding firepower for the sake of it.


I think it’s fair to say, the Batch 2s were bought to fulfil a contractual (ToBA) rather than capability (Fishery and/or any OPV) requirement. The safety requirements were non-negotiable add-ons to the design. Absolute minimum design change to the basis ship acceptable because timeline was driven by gap in steel fab work on the Clyde between PoW finish and T26 start.

So you’re looking at a class the RN didn’t necessarily want in capability terms, accepted gratefully as “new” ships, but now has to find a role for.

Steve Taylor

Yes. I know how B2 came to be. My question is, what then, given your knowledge of the RN, is the basic outline design for an OPV for UK waters?


Firstly good seakeeping for all-year ops from SWAPPS to Shetlands and beyond. Second, decent sustained speed (~18-20kts) for marking and/or interception of traffic. Accommodation for boarding parties. Boats for said boarding parties. WVR weapons for overwatch / hard stops. Simple propulsion and onboard systems for good availability. Decent endurance (fuel and vittles). Looks remarkably like a batch 1.

That’s pretty much it. Arguably, one could start wishing for things like RX-only data-link to get the RMP and small UAVs for surveillance, which are nice to haves. They bring with them the need for picture compilers and maintainers etc.

Steve Taylor

Thanks. Much as a I have thought / known / experienced for the last 30 years then! 🙂

It was my fault. When you said requirement I was thinking of it in terms of specification; I thought there some nuance or technicality of which I was unaware and you as an expert had taken into consideration.

While you were speaking in terms of does the RN have need of new FP hulls?

I do like the B1’s. In some ways perhaps the most successful acquisition of the last few decades. I have been aboard all of them except Clyde. Apart from the flight deck issue near perfect.


The 40mm upgrade with 30mm LMM would be the option which would probably be accepted by the bean counters we could hope a UAV will be included as this would be about as much as they would allow.


The 40mm as shared with the T31 would seem to be a no-brainier.
After that I’d say something like the Fire Scout MQ-8B as a drone for long range reconnaissance and some airborne firepower.


The Fire Scout MQ-8B is 30 times the cost of the S-100, 9 times the weight, and it won’t fit in a 20′ container. You might as well specify the even larger MQ-8C, which at least is a later model. Both are small helicopters and would probably need a hangar.
You could run two S-100s off a River with no real problem, but an MQ-8 at around half the price of a Merlin would be a considered purchase.


You get what you pay for. With the MQ-8B you get a platform that’s our US allies have extensive experience of using. As a result it can now undertake mine-hunting and can also carry Hellfire’s. It may not fit in a container, but a telescoping hanger could be added to the OPV.

The C is a essentially just a full-size manned helicopter that’s been automated. If you go for that then you might as well just go for a Merlin and be done with it – though I think both are unsuitable due to a lack of permanent hanger.

The B is a good compromise option.

The S100 would be best suited to our Border Force cutters, etc.


The Rivers _are_ mobile border-force cutters. The question behind the article is, should they stay that way?

I agree you get what you pay for, but what do you want the MQ-8B to achieve? You don’t need a Fire Scout to go mine hunting. And I don’t believe you really want to pay for the ability to use a tank-buster off an OPV. Of capabilities you’ve mentioned, that leaves long-range recon. But the combat radius of 110 nmi isn’t much more than that of the S-100 at 97nmi.

What am I missing?


“The Rivers _are_ mobile border-force cutters” – I’m glad someone finally said it


Saying River B2 is not maximizing its use is not correct.

River B2 OPV already has “maximize the use of herself” as having the >300 days “sea-going days per year”. More than twice longer than any escorts now. She can also be operated with only 36 crews onboard. Of course, adding weapons will degrade this top-ranked figure-of-merit.

It is only when the tasks needs it, when up-arming River B2 is needed. As, in place it will significantly lose the sea-going days and man-power friendly operation, you may need two of them to cover a place one was covering, and still you need 3 or 4 times more crew to do it, robbing these crew from other assets. (also robbing money from RN, which could have been used to up-arm T45, T26 and T31)

I myself is a “fan” of up arming River B2. But, we must not forget its negative side, as well.


I agree. Any upgrading of the O.P.V.s should be minimal, any extra money instead going towards Type 31.


100%. Corvettes are definitely not the way to go, not when both the T45 and T31 are going to lack a SSM capability for most of their service lives.

Meirion X

A River B2 deployed to the Gulf, would need to be accompanied by a T45, even armed with Martlet or I-SSGW.


Or a T23, assuming the River doesn’t stray too far.


Anyone who deploys an OPV to the Gulf should be relieved on command on the spot. The OPVs are there to do the low intensity missions so that actual warships are freed up to deploy to places like the Gulf. Which is also why they shouldn’t be up-armed (much), they need to do the low intensity stuff as efficiently, and dare I say as cheaply, as possible. If it’s causing the RN issues then perhaps a leaf should be taken out of the American book and the OPV’s transferred to a beefed up HM’s Coastguard (which in turn can come under RN control in a serious conflict or at least RN control within the AO of a lower intensity conflict), an RFA but with guns so to speak.

That said the OPV Plus in the article does have a lot to commend it, maybe go a little south of that: if the 30mm was kept where it is but the LMMs are added to it, and a spot found suitable for firing Starstreak and whatever the in service ATGM is these days covering the forward arc and another firing spot for the same weapons covering aft, along with LRAD and some decoy launchers – the latter fitted for but not with – then you would have the best you could do under the circumstances.


I looked at all the proposals and came to the conclusion that I think the best choice is a mix of OPV plus and corvette. Would I like to sea a Wildcat with hanger and a 57mm gun and 8 NSMs or RBS 15s, yes but that combination is to expensive for what you get.
I don’t know if the 16.5ton crane is a bolt on or deck penatrating, I hope a bolt on for what I am going to suggest.
First rather than the expense of a hanger and Wildcat we don’t have enough of these helicopter as it is, use the five sets of ARTISAN radars that will be left over from the T23s and install them on the BATCH IIs , then install a 40mm gun and two 30mm guns with LMM. Build two Camcopter hangers port and starboard of the Crane block. So now we have a OPV plus with Corvette electronic suite at no extra cost for the kit extened survalance range upto Sea State four and 15 degree roll.
Now for the reason of my question about the crane if it is a bolt on or not. If it is a bolt on it means that it is mounted on a strengthend deck and relitivly easy to remove. If that is the case then two things could be mounted there depending on requirements, the first is Sea Ram, the second is Typhoon MLS NLOS. If you don’t know what that is it is the Typhoon 30mm gun mount coupled with a 8 tube SPIKE NLOS launcher and its intergrated aquastion system. The heaviest piece of kit is the Sea Ram at 8 tons with its 11 missiles, I’m not sure but I don’t think that it would be heavier than the crane so that should not create any issue with top weight.
There is one additional option that could be installed on my verstion of the Batch IIs, if SeaRam was to be installed then rather than using Typhon MLS NLOS as you would only be able to carry either/or, have 2×6 launchers for Brimstone Sea Spear. They are designed for craft down to 15m have a range up to 25km a 16kg warhead can be fired in ripple effect against not only swarming fast attack boats but also against UAVs or missile salvos. They are also a fire and forget missile, the RAF Brimstones can be upgrade to Sea Spear.
So my overall configuration for littoral combat Batch II would be 1x 40 mm, 2x 30mm each with LMM, 2x mini guns, 1x SeaRam/16.5 ton crane, 2x 6 Sea Spear, 2x CamCopter S-100 and 2x Pacific 24 RIBS with a lillypad for Merlin II helicopters and don’t forget 50 Royal marines. Basically if the Batch II is on humanitarian duties then she is equipped with her crane, if in combat areas such as the Falklands/Persian Gulf SeaRam. I did look at SPIKE NLOS but discarded it due to its requirements although I do like the Typhoon mount, I also looked at Minstrel but discarded that due to range and technical needs. I have also looked at the aux equipment needed like power, cooling water etc, SeaRam needs power as does Sea Spear, Sea Ram could take the power from the same feed as the crane and does not need any targeting information, Sea Spear would need new power feeds but as these missiles were designed for aircraft I don’t think it will be 240v more like 24 or 48v, Sea Spear would need targeting information to start with but that could come from ARTISAN but it would need a data uplink for mid course correction or man-in-loop situations. Artisan would cover an area of 125,663sqkm whilst the Camcopter could cover a further 25,446sqkm, if Ive got my maths right. I have not included a small magazine for manual reloading the reason is simple it would need a dedicated space, it would need to have fire suppression systems it would reduce the capability of the Royal Marines. So in some ways its a one shot wonder and then fall back on the guns. The again if a OPV Plus Plus gets into a major missile war then something has gone really wrong and you need to call the big ships in.
The overall cost for these upgrades would be about £12 million per ship with one complete outfit of missiles each not including man hours.
That would give the RN a small ship with a big punch within limitations 25km. Then again even a large DDG would get out of the way of 12 missile coming at you even if they have only 16kg warheads.
What do you think?

Stray Vector


I mostly agree with your recommendations. I really like your recycling ARTISAN if that can be done without too much expense (I’m a big fan of reusing systems that outlive their platforms). I like the way you switch out the crane for non-deck penetrating weapons based on role; that and the use of ISO containers to support UAV, UUV, etc. is very flexible (sort of STANFLEX-lite).

One thing I would change is go for 57mm instead of 40mm for main gun since this is something that can’t really be switched out based on role. May be overkill for some situations but gives more capability than 40mm, is appropriate for most east-of-Suez roles, and would take advantage of the fact that you have installed ARTISAN. I would reluctantly be willing to give up Sea Spear to achieve this.

The other thing I would consider is using 40mm instead of SeaRam. The RN doesn’t currently use SeaRam and the 40mm could be shared with Type 31s, saving on equipment, ammunition, and training.

Overall I like your suggestions. Could be a new ship type. I wouldn’t call it a OPV or corvette. I’d call it a Sloop.


“I’d call it a Sloop.” A bit of a Black Swan, even.

Rob N

I do not think you would need Sea Ram, if you swapped it for some Sea Ceptor mounts along with the Type 997 radar you would het a useful anti-air and anti-surface capability. Sea Cepto can attack surface targets. Sea Ceptor is also much better then Sea Ram. The 40mm gun is a good idea along witg the 997 it can do anti-air and anti-surface and act as a CIWS. A countermeasures system would be useful too. The 30mm guns could be fitted too but this space could be used for mini guns and Sea Ceptor. Alternatively, put the 57mm on with a 40mm at the back instead of Sea Ceptor/Sea Ram. This configuration with3P amo would give anti-air, anti-surface and CIWS. You could add a couple of mini guns instead of 30mm.

David Broome

I believe we need to be realistic in terms of cost, so 57mm, wildcats and SSM’s are a no-go to Treasury and the Navy.

I’d rather see surplus kit like Artisan go onto Batch II T31s than into what we need to remember is a proposal to create modern sloops. As SeaRam would be a completely new system to the MoD it would not pass muster.

So it is all about Commercial Off The Shelf for fire control, Bofors 40mm main gun (but with below deck reloading because the 100 rounds a MK4 carries, without deck penetration, is gone within 20 seconds at a full rate of fire); a 30mm on each waist with five coaxially mounted LMMs (to augment the 40mm for surface and slow air targets).

I would definitely go for Spike NLOS. It is known to the MoD as the British Army’s Exactor and in an 8-cell naval launcher, has a similar footprint to a 30mm and could, with minimal modifications, be slotted between the mast and funnel. As a light SSM with a 25-30km range it could fire to port or starboard. Combined with a pair of ISO containerised S-100’s (inclusive of air-conditioned control and operations room), this creates a small warship capable of escorting cargo vessels with Spike deterring boghammers/pirates as the S-100’s provides beyond visual range targeting and course correction.

What I propose would need deck penetration into the magazine (for reloading the Mk40) and a strengthened platform between the mast and funnel (for Spike). Aside from fire control, it leaves everything else, flyco, firefighting, cranes etc in-situ. It furthermore does not need many more crew (another consideration).

The sum I estimate for all-five is around £25-£30 million and maybe less.


The obvious answer to up-arming the B2s and to keep costs down, is to keep the equipment required with what’s currently or will be in service. I don’t think the B1 should be up-armed as they are more suited to fishery and police duties.

With the T31s being mostly a gun-boat, some of its weapons could be migrated to B2s. The 40mm would be an obvious choice as its relatively light and has a high rate of fire. The problem is it doesn’t have the punch or flexibility of the larger 57mm (6 pounder!!!) The 57 is about half the weight of the OTO super rapide 76mm gun. It has a very high rate of fire, decent reach, but can also fire guided rounds. It can be either deck or non-deck penetrating. It would need a link to the ship’s radar, which should be a upgrade of the Scanter to a true 3D system. Fitting a pair of DS30s either side of the bridge is a no brainer, along with the LMM fit. These options on their own would offer a significant enhancement of what it currently has.

To further improve the reach of the ship, a helicopter would be the gold plated solution. But on cost grounds, manpower and modifying the aft deck for a telescopic hangar, would significantly push the cost up. The more affordable option is housing a pair of Schiebel S100 VTOL UAVs, using an iso or new purpose built mini hangar next to the crane. This little UAV is proven and used by a number of Navy’s around the World, even by the Russian coastguard. For an offshore patrol vessel, this would really enhance the ship’s situational awareness, especially what’s happening just over the horizon.

To get even more fighty, I propose the ship could be armed with containerised Sea Venom (MBDA first trialled it from containers before attaching them to helicopters). The reason for this is the missile is classed as a within visual range weapon, so can be used with the current rules of engagement. The weapon has a two-way data link so it can be used for selected targeting on ships, but it can also be used against land targets. Perhaps more importantly it will be an in-service weapon, so the weaps trade will be fully ware of it with training in place to maintain it.

I’m not including a dedicated anti-air weapon/missile system as that would push the ship into the realms of a proper corvette and costs nearing the T31. However, the DS30 should be adequate to deal with slow moving helicopters or UAVs. The LMM has proven itself against faster moving UAVs and tops out at Mach 1.5. The mount could handle replacing the LMM with Starstreak HVM, as the laser guidance for LMM is the same. However, the ship with the 57mm Bofors, using guided rounds combined with the NS100 radar would make quite a formidable anti-aircraft/missile combination.

By up-arming the B2s to include the Bofors 57mm, a pair of DS30s with LMM, containerised Sea Venom, Scheibel UAV and an upraded 3D multi-mode radar such as Thales NS100. The ship won’t be a corvette as such, but will be more flexible at what it can be used for, being able to defend itself, but more importantly punch back!


While I agree with most of your post, what is the point of LMM without a helicopter? Both the 40mm & 57mm outperforms it. LMM is a great add on to a PB or RFA vessel armed with 25/30mm or something like T26/T45.

Would something like NS110 really be necessarily? Would the Scanter 6000 do the job ? (not arguing – genuine question). Fair difference in price & integration cost. RAN have gone with the Scanter 6000 & 40mm combo. Like the Sea Venom idea. If you are going to fit NS110 to B2, then really need to fit NS200 to T31.

While much of the AAW missile talk has been about things like CAAM, it requires a reasonable radar. To be out there, what about a Sinbad mount & Mistral missiles? They are IR based, not RF. Short ranged, yes, but cheap & not radar dependant. Also reloadable by crew. Or an IR based CAAM (after all CAAM is based on a long range air launched IR missile).

On the 57/76mm, any concrete evidence of which way T31 is going? The 40mm seems a given.


The Scanter is more designed for surface search. It has the capability for searching and tracking objects up to 6000ft at distances of 10 to 15 nm, depending on the objects size and RCS. For what its size it is a very capable radar, which is why a lot of navies use it as either their primary radar for OPV sized vessels or as a back up to their primary 3D radar on larger vessels. The main issue it has though, is it’s not really designed for engagement tracking i.e. linking it to a fire control computer, which controls the weapon system. It is an X band radar with variable pulse repetition frequency. Which means you can up the number of streams it is transmitting when an object gets closer to the ship. The main issue is that it is still a traditional pulse doppler radar using either a conical fan or straight array antenna. This limits how narrow you can shape the beam, but also restricts its sweep to preset angles. This is where you need a dedicated fire control radar or a multi-mode PESA/AESA radar like Artisan or the Thales NS series. The complete Artisan system i.e. antenna, cooling, power supply conditioning and control may be too large and heavy for the B2s, you may have to sacrifice a lot more space to accommodate it. It is a twenty years old system now, so more modern radar are just as powerful, but packaged much smaller. This is the reason I suggested the NS110. It has the same capabilities as its larger NS200 brother, but at a reduced range using a smaller/lighter antenna.

The main reason for the inclusion of LMM is the missile’s flexibility. It can be used against small boats, UAVs and some aircraft. The majority of aircraft flying at sea level will be subsonic, so most could be fair game. But it will depend on early detection, relative crossing speeds and distance. The system uses the same laser guidance as the Starstreak anti-aircraft missile. The Starstreak HVM accelerates to Mach 4+ in just over a second after leaving its tube. The newer version has a similar range to Martlet. It has a number of advantages over IR or RF guided missiles in that it is next to impossible to jam. But, it still has to be “command guided” to the target as the laser matrix must be kept over the target for the missile to home in on, its not a fire and forget system. Its’s also questionable whether the system can handle multiple simultaneous engagements. However, it can be fired from the same magazine attachment as used on the DS30 mounts.

Effective range and maximum ranges are two different properties. The Martlet’s effective range is still its operational range of about 8km. The 40mm has an effective CIWS range of 2500m against a sea skimming missile, whilst it has a effective range against surface targets of nearly 10,000m. The 40mm can use the 3P round, which has a multi-purpose programmable fuze, it is not a guided round like the 57’s ORKA round. Therefore, you still need to put a lot of lead downrange to effect a hit.


The key problem with the 40mm conveniently overlooked is that it is a rapid fire weapon which is not deck penetrating with only a 100 rounds in the turret which will be dispensed in a very quick time….. what happens then? Back to the days of WW11 when someone is going to have to physically re-arm the gun…..and considering where it’s mounted on the Type 31 Corvette, that is not going to be easy, specially in the middle of a fight….

David Broome

There is a deck penetrating option for the 40mm into the magazine that would be a must, otherwise, it’s a complex and manual process after 20 seconds at a full rate of fire! Also why having the 30mm on the waist with LMM would be a must.



Sorry I am a bit late on this. Thank you for your detailed response.

The Ginge

Great article on what can & can’t be achieved with B2 Rivers. However, we need to decide what we want or more likely need these Ships to do. Originally they were intended as make work projects never intended to anywhere beyond UK EEZ and to deal with some angry French Fisherman. They may still have to do that but the B1’s should be retained to do this (paid for out of Dept of Ah & Fisheries budget !) .
But the reality is that with cuts to T26, muted delays in T31’s, possible early retirement or cutting Slep of T23’s and known T45 problems these are hulls in the water and me be asked to do things that the RN in reality would rather send a T26/31/45 but with Carrier Escort Duties it is unlikely those assets are going to be available. So what do we need these Ships to do
1: Protect Merchant shipping from small boat & OPV attack and “arrest” by state players such as Iran/China. If it gets to that level then the RN is deploying more assets pretty quickly but Rivers need to hold there own in the first engagements.
2. Protect Merchant shipping and itself from limited air attack. Nobody is suggesting a River could protect itself from a coordinated multi aircraft swarm missile attach. For that you would need a T45 or T26. But they need to be able to protect themselves and charges from State Actors testing UK resolve . Again the reality is if for example Iran fired of a land based anti Ship missile at anything both the UK & USA are going to be sending some pretty large amounts of Steel to the region. But the Rivers need to be able to survive a limited attack and not gift Iran a publicity show of a smoking British Hull.
3. To interdict by air either Helicopters or boats/ships for inspection & anti drug/weapons smuggling. It’s no point have a detachment of Marines in board but they can’t catch up with anything because they are limited to a rubber boat.
4. Wide area surveillance. We need to be able to see what is our there and what is coming its way. This allows the River time to best manoeuvre itself to deter or counter any threat.
5. NOT anti Submarine operations since even a T31 is going to struggle to operate in that environment.
Whilst in ideal world T31’s and other bigger ships would be doing this the reality is that we don’t have the numbers or crew or at sea days to cover everything. The RN has to accept it’s cash strapped and like the army deploying light infantry brigades to the Baltic the Rivers will have to be trip wires in some pretty hostile places just so as not to wear out their bigger cousins. So then suggest the equipment that achieves 1 to 4 make it light in manpower, able to operate 309 days a year, non hull invasive and to honest the cheapest ready to bolt on equipment available.
Rivers can then be rigged with appropriate level of equipment, doing fisheries work off UK post brexit good as they are, going to the Gulf then upgrade quickly ( two weeks maximum) and keep the Ship doing that work out there rotating crews in.

Stray Vector

I think the comments made so far about including Royal Marines are really good ones, and the one by Ginge about their needing something beyond a rubber boat is a good one. However, Unless the RN can get some AW159 from the army, I doubt any helicopters would be available, even if a (telescopic?) hanger could practically be installed. So what options does that leave that wouldn’t take up space on the flight deck?


Please, if we do have 2 enhanced “B2s”, “corvettes”…. please can was name them the Shannon and the Chesapeake?

Gavin Gordon

I know it is reliable and I expect it’s pretty lethal, but I cannot recall seeing a decent publicly available video of the 30mm ASCG in operation under remote control and against realistic targets. The Bofors 40mm with programmed rounds, however, is an impressive piece of kit when observed ulitizing either a single shell or four in rapid fire. Against that, the apparent ease with which our 30mm can accommodate LMM is worthy of note.
Still, so long as there is a credible RN enhancement plan for the B2 in the background should the need arise, there’s no need to rush to any upgrade for the time being.


Problem is 40mm is longer ranged than LMM for a similar outcome. If all you have is 30mm, then LMM is useful (or on a helicopter). 40mm shells are cheaper than LMM missiles & P3 ammo has additional uses that the LMM can’t match. LMM strikes me as too short ranged, too small & too expensive to bother with. Want to test fire 20 rounds of 40mm, not a problem. Want to test fire 3 LMM – best get it in writing first. Yes, it’s a cheap add on to a 30mm, provided you never fire it.

I agree, the Bofors L70 based systems with P3 ammo are impressive for the money. The problem for RN is while there is no rush today, there may not be time tomorrow. It’s not just the time to change the gun, it’s getting everyone up to speed, etc that takes time. T31 may be in the water sometime in 2023, but it won’t commission until some time in 2025 if we are lucky (more likely 2026 – later if not in the water on time). T23 are supposed to start retiring in 2023. If B2 is to help fill the gap, they have 3 years to get it competitive.

David Broome

I agree except 30mm/LMM provides redundancy in a swarm attack and augments the 40mm. Especially if it is from all points of the compass The 40mm has only 100 rounds unless there is deck penetration (even then its manual reload so the firing rate would drop off). Furthermore, LMM leverages Starstreak so provides a rapid anti-air solution against UAVs and helicopters off the port and starboard beams.


Would Starstreak be a better option?

Geoffrey Hicking

Add a drone and leave it at that. Even that might be too expensive. We have a vast amount of cuts to make and the MoD is never going to live within its means. It hurts to write that but its true.

Bloke down the pub

The article claims the Rivers are ‘lacking the space even for a compact towed array sonar’. Considering that the Geospectrum Traps system fits in a TEU and is being fitted to RCN Kingston opvs, I somehow doubt this. I have contacted company representatives and while the system is currently designed to operate over the stern , precluding the use of the flight deck, it is possible to use it from the container positions on your illustrations.
Mention is made of the pannier mounting for LMM. I’ve seen it suggested that Starstreak can also be fired from this mounting, can anyone confirm this please?


I was considering this too as they’re very closely related, but with different warheads afaik; not sure if the containerised launcher of the Starstreak differs though. That aside, I’ve read that Martlet has comparable surface-to-air ability anyway.

Bloke down the pub

Comparable ability only against slow moving targets such as small drones. Any serious threat, such as an anti-ship missile like the Yemenis used against a Saudi corvette, would require the efforts of the specialised weapon.


Ah ok. So starstreak has anti-missile capability? Presumably much higher velocity if so (I know it’s fast, I didn’t realise the martlet was slower).


Before we even think about fitting any type of towed array sonar on the B2s we need to fit on Type 31 Corvettes first.

Humpty Dumpty

Paul: What’s the point of fitting towed array sonars to either the Type 31s or uparmed Rivers? They’re both purely diesel powered and noisy. They’d need to use CODLOG propulsion like the Type 26s will be getting and also be designed to be as quiet as possible in other ways to even be considered in an anti-sub role. But then in addition to towed array sonars, they’d also need VL-ASROC, Merlin HM2s, bow sonar and SSTD. Some sub-hunting Arcims surface drones and SeaSpider anti-torpedo torpedoes wouldn’t go amiss either. It would make no sense to send Type 31s or uparmed Rivers anywhere where there are likely to be subs about, they’d be sitting ducks. As for anti-ship missiles, I wouldn’t want to rely solely on Bofors guns to take them out. I’d also want some kind of anti-air missiles on board, preferably fitted in ADL launchers that can be replenished at sea. Also, if the Bofors gun that’s fitted isn’t deck-penetrating to allow for reloading, it could be out of ammo in just 20 seconds.


“Enhancing the lethality of the Batch II Rivers” sounds like someone has been reading the Thales brochure on LMM. This project is code for ‘ we are going to lose 3 Type 23s and the Type 31s won’t be ready so we need to deploy the Batch 2 Rivers.’
As I see things, in order of ££
1.LMM will enhance against FIAC and against helicopters but has no true AA or anti ship missile capability
2. Adding a UAV good for anti piracy
3. A Bofors 40mm adds some AA and anti missile capability
4. A Bofors 57mm adds range and offensive hitting power
5.NSM and / or helo expensive and out of place, send a frigate.
So I reckon option 1+2 is the way to go for Somalia anti piracy and Iranian Revolutionary Guard FIAC. Add option 3 and you have ‘some’ defence against Yemeni rebel AShM but not against Iranian Navy who are professionals.


I’d go for 1,2 and 3. The 40mm because it means you can comfortably out range any Kornet ATGM that may have fallen into the hands of Somali Rebels / Pirates and dominate the engagement, also gives a measure of AA.

So OPV plus to fight non state actors, do wide area surveillance and contribute to protection of merchant shipping.


Yes to 2 & 3. Don’t see the point in 1 if you have 3 (or 4). They can do the same job but at a longer range & far less money.


That is exactly my thought when I read RN Commander Operations comments. In the previous article about SDR20 which suggested 3 Type 23’s could be sacrificed. I think this is cover for escort numbers even more. I still wonder how secure the Type 31 program is. Have the contracts been signed?


Contracts for 5 signed before the election.


Let’s hope that they have locked the MOD into the contract in the same way that Aircraft Carrier Alliance did!

Mike O

There are smaller, faster, better equipped fast attack craft designs such as:

Leave the OPVs to open ocean constabulary and use some boats like the Fs65 for low intensity combat roles. Cheap to crew while providing command opportunities and some genuine capability. Also fast enough to run away if it catches wind of something it can’t handle.


My crazy idea of increasing Royal Navy surface combatants – As suggested in the article upgrade armament of the Batch 2 OPV with a 57mm Bofors main gun (compatible with Type 31), add 2 30mm guns and ASCG and LMM systems on the side. Add a telescoping Hanger to accommodate a Wildcat or remote controlled helicopter and add the armed USV for a limited anti-sub capability. As the Type 23 frigates are retired from those that are not sold I suggest the Harpoon Anti-ship systems get refurbished and installed on the OPV (4 cannister array) with the required fire control radars. Finally of the best unsold Type 23 I would retain 4 of them for a Home Fleet (2 stationed in Scotland and 2 on the South Coast), manned by reservists. These Frigates would do the Home waters shadowing of passing Russian ships etc. and support the Coast Guard and Fisheries protection fleet. Use of reservists or part-time civilians will solve the manning problems since essentially only 2 vessels need to be ready at anytime with the other 2 in reserve or repairs. The retained Type 23 can also act as seagoing training ships for cadets. Doing what I am suggesting will add 9 (5 Batch 2 and 4 retained Type 23) fairly capable combatants to the expect 8 Type 26, 5 Type 31 and 6 existing Type 45 to give a decent fleet of 27 ships. Cost of my suggested upgrades should be minimal. The 57mm should cost less than US$10 million per gun, the 30mm cannons should cost nothing since they can be taken of the Type 23 (the OPV already has one currently installed). The ASCG system according to Wikipedia cost the MOD US$30 million to purchase 26 for the Type 23 so I expect a new buy to be less than US$2 million per system and 10 would be needed for the OPVs or they can be taken off the retiring Type 23s. For the USV system, the most expensive upgrade, the reference Israeli Seagull systems costs range from US$12-25 million. Total hardware cost for my outlined upgrade is expected to be in the region of US$200 million for the 5 OPVs excluding the refurbished Harpoons taken off the Type 23 and the shipyard work costs to get the systems installed. Cost of retaining 4 Type 23 (they just got midlife upgrades if I remember correctly) I do not know. I am sure there are more qualified people in the forum to speak on this matter.


Isn’t there a huge danger here that the beancounters in Whitehall will see the up-armed Batch 2 Rivers as cheap replacements for frigates?

Gavin Gordon

I understand the theory, at least, is that the Treasury fund credible and balanced equipment proposals from the armed services within UK overall financial contraints. They do not see themselves as having the knowledge to dictate technical requirements beyond that remit.
Thus, it would appear that only Dominic Cummings has sufficient regard for his abilities to run counter to that methodology, perhaps lubricated by the occasional late night tipple.

Captain Nemo

I generally agree, ‘freeing up high end warships’ etc, etc while using that as an excuse to reduce the number of high end warships.
I’m just half of the opinion now that, since we’ve got them, if we up arm to corvette, then maybe, just maybe, they place hold for a batch 2 T31.


I think we have passed that point. We are keeping 3 Batch 1 Rivers, the RN can’t man all its current escorts, the Type 31 program is running late, the T26 program looks to be deliberately slowed and Brazil would buy 3 lifexed T23s. I don’t think you have to be Mystic Meg to see where this is going.
Forth and Medway are already on their way. Trent, Tamar and Spey will receive the minimum enhancement to enable them to replace the T23s we will lose and be useful against drug runners and pirates in the Indian ocean; a containerised UAV and either LMM or a 40mm, but probably not both. Significant cost and manpower savings.


I think they need better sensors, not better guns, at least in peace time. I’d hope there’s a plan to turn them into corvettes quickly enough if there’s a war, but for now they are OPVs and should stay that way.
So two S-100s and a base station. Probably about £2m, plus half-a-dozen operators for all three shifts. I’d fit the Martlet option for higher threat environments (east of Suez).
As the Type 31 won’t be using them, I think there should be some (three?) spare Artisan 3Ds from the Type 23s. Finally, if there’s a reasonable option for small-footprint ELINT, I’d consider that. Having ships puttering around the world’s oceans seems like a good opportunity to keep some ears listening.


+1 for a SIGINT fit. In this day and age, we shouldn’t have a platform that can’t add to the information picture!


I predict this thread turning into another 100+ comments scenario!

For what it’s worth anything which actually improves their capabilities in their core surveillance and patrol roles in the benign environments around The UK, West Indies and South Atlantic (benign in the military sense) then i’m all for it. Out of all the possible enhancements touted i think container stored and operated UAV’s would make a lot sense as a relatively cheap but fantastically effective way of extending the vessels surveillance radius and persistence without the need for helicopter’s and hangars.

Ok so maybe a case can also be made for a slightly better defensive armament, Martlet launchers on the 30mm for instance, or at most an upgrade to the 40mm system, but beyond that i really cannot see the sense in trying to turn OPV’s into budget frigates.

We’re building T31’s specifically to operate in places like The Gulf and South China Sea. Big and well armed enough to defend themselves and shipping in the vicinity and to have decent survivability/endurance, but also simple and cheap enough (hopefully) to be procured in greater numbers and allow the high-end surface vessels to concentrate on their primary role of escorting the fleet’s capital ships.

Sticking bigger guns, hangar’s, Sea Ceptor, AShM’s etc on small (OK the size of early Cold War frigates but not that big by today’s standards), relatively slow, and as the article pointed out very noisy patrol ships when that money could be spent better elsewhere would be downright irresponsible to the sailors on-board being put in harms way as well as being illogical from a financial standpoint.

It’s good we’re going back to 8 OPV’s as 4 was always too few, but use them around The UK and as forward presence in the Overseas Territories and find other ways of fulfilling the Royal Navy’s growing commitments East of Suez.


Modern OPV are capable of 300 days sea-going per year. Very different from 7 Island class Patrol vessel and 2 Caslte class OPVs in early 1990s. I understand 3 River B1 OPV was intended to replace 7 Island class on 1-by-1 basis, not in view of hull number, but in total-sea-going-days (thanks to its long sea-going days and high sea-worthyness). 1 River B1.5 replacing 2 Castle class may be a little decrease in total-sea-going-days, but not large I guess.

Lee H

Hi Challenger
I concur, the RN is slowly getting to grips with the manpower it has got, the shipping it needs and the context it will soon be operating in post the next review.
With the 8 OPV’s we have soon we will be back into the 3 tier “fleet” the RN was looking at in the early 2000’s, C1 being high end specialist escort (ASW or AAW T26 and T45 totalling 14 platforms), C2 being general escorts and low intensity patrol (T31 and B2 OPV totalling 9 platforms (increase to 12 if T31 increased)) and C3 being your MCMV and other patrol vessels etc (potentially up to 16 platforms) giving a total “fleet” of around 40 vessels which isn’t too bad.
Each tier within the “ORBAT” could potentially share weapon and sensor fits, for example fitting T31 and OPV B2 with the same sensor and gun suite (sharing 40mm not 57mm). C3 could have the 30mm MARTLET fit as standard again along with a common sensor fit.
Wildcat could then be aligned to the C2 and C3 platforms with the Merlin aligned to the C1.
Within RN Command then flotillas could be rearranged based on capability:
C1 Flotilla with 2 squadrons (FFG and DDG) – Portsmouth Based
C2 Flotilla with 2 squadrons (FFG and OPV) – Plymouth Based
C3 Flotilla with 3 squadrons (OPV, MCMV, Survey) – Faslane/Plymouth (Survey) Based
CVF would continue at Portsmouth, Ambhibious would continue at Plymouth
All Submarines would continue to Faslane.
The C2 flotilla would operate on a “single platform, double crew concept” – ships would be forward deployed but crews, as they do now in the MCMV fleet would rotate – all training completed in Plymouth through FOST.

Yes, I have gone off in a bit of a tangent – however, we don’t need to “over-weaponsise the OPV just give it something that can be afforded and appropriately used.

Supportive Bloke

Over weaponising the OPV’s will just lead to them being sent to areas too hot to handle.

That being said an automated 30mm each side with Martlet is a big persuader to keep a distance.

I would rather see the proper high end warships 45/26 fitted with MK41 VLS. I would also be in favour of the T31 having 8 cell VLS even if nothing much was in them most of the time. Once VLS is there it can be armed up quite quickly. Anywhere with a decent crane can do the loading IRL.

Having VLS puts a big question mark to an adversary – can they gamble on it being empty?

Ultimately the calculation is – if I attack this thing, do I end up taking a massive risk that the response is unpalatable. If that level of response cannot be delivered then the ship is in the wrong environment.

Likewise people often bleat about the level of AAW that 2 x T45 can deliver. Honestly with 96 shoot downs plus what 2 x T23/26 can deliver in a close in argument that is a lot of aircraft/missiles you have to say goodbye to prosecute an effective attack.


The main problem with 48 forT45 is that most frigates carry 8 x ASHM, & some carry 16. Most multi-role fighters can carry 4 or more AShM (eg F35A can carry 2 internal & 2 external JSM without a problem). A flight of 12 Fighters can put as many missiles in the air as a single T45 has. After that, the T45 is gone. Hence the need for a quad packed option. There is allocated space on a T45 for 16 more cells. 16 quad packed CAAM gives you 64 more missiles. Not as good I grant you, but a better chance of keeping you in the game. No one with any sense is going to put a fighter within range of a T45 on a real rather than demo scenario. With long range AShM, no need to – fire your missiles & head off for a reload. It’s who runs out first that looses.


Adding one of the new Sea Class workboats to their fit out seems like a sensible idea to me. From pictures it looks like one of these would fit in one of the container positions either side of the crane. Hosting a UAV in the alternative position would complete the package.

Adding one of these would add flexibility in HADR situations (ship to shore delivery of aid / personnel), troop transport (as highlighted recently on Forth – how to land the troops, not just transport them) and in the ability to operate off ship platforms (USV, UUV etc).

An alternative option is to have two containers either side of the crane and the workboat on the flight deck in the forward-most container position (the one that is perpendicular to the others, across the ship – this should not compromise flight operations). This would enable a UAV to be housed in one container and various Sea Boat ‘add-ons’ in the other (eg. USV etc).

The ‘bolt-on’ design of these new workboats means that additional packages could be flown out if required. For example a dive module may be flown out to a destination in the Caribbean and loaded on to the OPV if the need was there for prolonged dive activities in the region. Additional modules will likely develop over time.

Stray Vector

How fast are the sea class boats and how people can they hold?


Rather radical, I actually hope to cancel T31 program, to save 2B GBP. I know this is politically not going to happen, but the 2B GBP is very very precious now for RN. It was “1.25B GBP” at the beginning of discussion, inflating to current value.


Option-1: Re-design T31 to more simpler program, may be a more “Floreal-like” presence ship, with say, two 57 mm gun (to cover 360 degree), a Wildcat, two 30 mm guns with LMM (again 360 degree) and nothing else. Build FOUR of them (not five) within 1B GBP (including everything).

In this case, we get the remaining 1B GBP. I shall add 1 more T26 (~800M GBP), and then 200M GBP for small improvements on T26s. The “very light T31” significantly overlaps with “up armed River B2”, so there is no need to up-arm the latter.

This will give RN with 6 T45, 9 T26 (all fully manned), 4 T31-light, 5 River B2 (EEZ) (River B1 will be disbanded by then)

Option-2: Order TWO more T26 with 1.6B GBP or so, and re-role 300M GBP to “slightly improve” T26 armaments, and use remaining 100M GBP to make TWO of the five River B2 a “super OPV” = say, three 30mm gun all with LMM, and a 20 mm CIWS (in place of the crane), with UAVs. By this simplicity, their sea-going days can be x1.5 of an escort (say 120 x 1.5 = 180 days or so = achievable I think).

This will give RN with 6 T45, 10 T26 (all fully manned), 2 River B2 (heavy), 3 River B2 (EEZ) (River B1 will be disbanded by then)

As you can see, I pretty much struggle to find some money, and even so, struggle to justify up-arming River B2. Don’t get me wrong, I am a big fan of up-arming River B2. But even so, I struggle to find a way to make it …..


Donald, are you playing devil’s advocate? I see budget and strategy driving the fleet mix in the opposite direction. If we cut T26 numbers to 6 that would enable us to build more R2 and T31 and arm them better. Does T26 really need the expensive 5in gun? Surely it is too valuable to use for NGS. And does it really need Mk41 VLS , for what? Wouldn’t the 5in gun and the Mk41 be more relevant on the T31? As regards a RN ‘Floreal’ class ( circa 90m) I see this as River batch 2.5 ….40mm and UAV or maybe batch 3 with telescopic hangar and helicopter. We’ve got a River class production line up and running now…..incremental cost of additional variants should be modest. Black Swan sloop squadrons here we come!



Floreal class is a 93.5m 2,600-3,000t light frigate armed with a helicopter & 100mm main gun. It’s way above a present B2 configuration. The Arrowhead 140 is an updated IH frigate. How much you underarm it is up to the buyer, but it has the capability of going to a AAW based heavy NATO class frigate if you want to. T26 appears to be a world class ASW based frigate. It also has to the capability to be a high end AAW frigate if you want to spend the money (as Canada & Australia are doing).

Fit the NS200 radar & 32 mk41 & 127mm (or even 76mm) plus 8 NSM to T31 & you will have a world class GP frigate. Head to head, my 5 x T31 outclass 2 x UK spec T26 for less money. This not to suggest a reduction in T26. T31 is ASW capable, not ASW specialised, but IMO I would rather 5 my spec T31 than 2 more T26, with money left over to up arm the B2’s. The whole strategy & design of the IH frigate was to get the most for the least. It’s that last 10% that kills you cost wise (see T26).

Humpty Dumpty

DJ: The Type 31 will be purely diesel powered and noisy, so it’ll be totally unsuited to anti-sub warfare. Plus from what I’ve read about it on this site, it’ll have no bow sonar, towed array sonar, VL-ASROC or SSTD. Will it have a Merlin HM2? A Wildcat’s only of limited use for anti-sub warfare. And as a sidenote, I’d like to see the Type 26s fitted with sub-hunting surface drones like Arcims or Seagull as well as SeaSpider anti-torpedo torpedoes.


The IH frigate meets minimum NATO specs for ASW operations (as is). This does not of course make it an ASW specialist, but ASW capable. IH is capable of & has facilities for operating a towed sonar if required. Babcock has directly stated that A140 has the option of rafting the diesels if chosen at build which would further enhance its ASW ability. IH frigate is equiped with 32 strike length mk41 VLS which supports ASROC. T31 is based on the A140 which is itself a modernised & updated version of the IH frigate. Plenty of destroyers & frigates around the world operate towed arrays, carry ASW torpedoes &/or ASW helicopters etc without specialist propulsion (T45 excepted). They just don’t do it as well as T26 / ASW T23 / ASW FREMM etc.

The ability or inability for T31 to do ASW operations is purely up to UK MoD & of course – money.

Humpty Dumpty

An IH frigate has 32 SM2s, 24 ESSMs, 8-16 Harpoon Block II missiles, an Oerlikon Millennium Gun, 2 76mm guns, bow sonar and torpedo launchers. It’s better armed than the proposed Type 31 shown here: which has just 3 Bofors guns and 12 CAMMs. Arguably CAMM is better than SM2 or ESSM, but 12 is a woefully low number, plus the Type 31 will have no anti-ship missiles, which I think would make sense since it’s better to have them and not need them rather than the other way round. My preference would be RBS-15 Mk4 if available before the Type 31s go into service. I’d also opt for CAMMs in 2 ADL launchers (that can be replenished at sea) providing 32 CAMMs. I’d also fit MASS decoys to provide another layer of defence against anti-ship missiles as well as 2 DS30Ms enhanced with LMMs to provide another layer of defence against FIACs.
Originally the Type 31 was going to have a bow sonar, but that’s been removed and it was going to have 24 CAMMs and that’s been reduced to 12. It wouldn’t surprise me if the Type 31 has no CAMMs at all once it’s built so it can come in on budget. Will a Merlin HM2 be *permanently* embarked on Type 31s? And will the Type 31s have SSTD? The image in the link above shows no SSTD and says “Merlin-capable hangar”, but doesn’t say if a Merlin will permanently embarked. Fitting a towed array sonar is pretty pointless without a permanently embarked Merlin HM2 or VL-ASROC (i.e. a means to take out a sub). That said, using a purely diesel-powered vessel for sub-hunting, even if the engines were rafted, would be far from ideal. In fact it would be pretty dumb. That comment applies to the IH as well though.
Plus what is the Type 31 going to be used for? And where? I expect it’ll be used to escort commercial vessels in places like the Persian Gulf. It’s not well armed enough for anything else. But uparmed Batch 2 Rivers could do that job at a fraction of the cost and they could do it now, now it 7 years time. Just fit an ADL launcher with 16 CAMMs, 2 DS30Ms enhanced with LMMs and MASS decoys on a River. If an Oerlikon Millennium Gun would fit on the front where the current Bushmaster is all the better.

Last edited 7 months ago by Humpty Dumpty

It all depends upon what you want your OPV to do. Now with Brexit I would suggest that these ships are going to be tied up in fishery duties anyway, meaning their present weapon fit is all that is needed. Beyond that there is a need for a ‘fly the flag’ counter piracy / drugs role and a surveillance platform for escorting foreign warships. In these roles an effective gun system to counter fast attack craft and provide initial air defence seems wise. A 40mm Bofors main armament would be great and a couple of bridge mounted 20mms with arcs to port and starboard would give a more than adequate punch. Perhaps the most important addition however would be some form of beyond the horizon surveillance vehicle. I don’t think a helicopter is really an option; to start with we just don’t have spare Wildcats and the telescopic hanger is a far from perfect solution. However a UAV could fit nicely and be of great utility. Perhaps, with a UAV containerised deck area, the UAV could be replaced with a mine hunter submersible, launched from the boat deck davits, in a mission specific manner. I doubt any of this will happen because of budgetary pressures which is a shame since these vessels, being nearly 2000 tons, are in theory quite capable mini warships. At the moment, if we went to war, these vessels are entirely worthless.


NAS 700X who are experimenting with drones are going to see aboard HMS Mersey for a week’s trials, so a drone of some description is likely in the discussed upgrade.

Mike D

What an excellent idea. With the RN set to have an increased global presence, circumstances could arise where a B2 is the nearest UK response to a rapidly developing situation. A military coup in the Pacific for example. As such having a gun that could actually support SF or Marines ashore would be very valuable. I endorse fitting the 57mm and the Sea Class workboat but what about having a smaller less expensive helicopter than a lynx such as a MD500 or Squirrel, both of which are in Naval use .


I don’t understand why the Royal Navy is messing about with Puma, a 7kg fixed wing with limited sensors and a flight ceiling of a few hundred feet.

Contrast that with the coastguard, who are running trials on the Israeli Hermes 900 drone. That operates with a ceiling of 30,000 feet and uses a Gabbiano (Leonardo) T200 radar to view up to 200 nmi.

Shouldn’t the Navy at least be evaluating rotaries with a flight ceiling of 5,000-10,000 feet and a visual/radar range of 100 miles? Given the Leonardo’s announcement a few weeks ago that it will be producing radar receivers with four times the power and a tenth of the weight, isn’t long-distance airborne radar the future of maritime patrol?


Wonder why the choice of the Schiebel Camcopter S-100 instead of the Insitu Scaneagle, if remember RN had successful trials with one in the Gulf on a T23, using a wing instead of blades Scaneagle endurance approx three times that of a S-100.


– ScanEagle is lightweight with a payload capacity of 3.5kg. The Camcopter is medium weight, payload 50kg.
– Although both systems have a variety of sensor types, its carrying capacity means the Camcopter has the superior set of sensor/payload options, including light missiles.
– ScanEagle has a fiddly launch and retrieval system, requiring a mini-catapult and a skyhook.
– Although ScanEagle has by far the better endurance, the range for both systems is limited by the link to the controllers, and ScanEagle can’t go as far from the ship as the Camcopter.


“Fiddly launch and retrieval system” is a bit of an understatement! There are two separate items – launch catapult and retrieval skyhook, both of which are trolley-mounted and are of comparable or larger size than an S-100.


Existing 30mm to the rear, add Martlet. 57mm already purchased for T31 on to the front. 127mm common to the T26 added to the T31 in place of the 57mm; hello NGFS role. Done. One of the cheaper options too?

It’s all academic until ‘high threat environment’ is actually defined, as even up-armed you’d be mental operating these as singletons in an adverse air or sub-surface threat environment. But what job would they do in such a guise under the AD and ASW bubbles of a CSG?

But if you’re talking non-sophisticated or asymmetric ‘high threat’ then that fit will see you reet for any LoS targets.

Stray Vector

Instead of 127mm on T31, how about recycle type 23 4.5 main guns if practical. Not common with type 26, but common with type 46 main gun and saves money.


I suspect the best we can hope for is a 40mm gun. If we did want coastal ASW, would a mini towed array sonar, like the DSIT Swordfish, that only needs a small winch & thin wire, be suitable? Perhaps use it to aim a SAAB anti submarine grenade system? Great for keeping hostile submarines away from Faslane.


If we want a helicopter on batch 2, does it have to be Wildcat, as we are short of them anyway? Compare Wildcat, MTOW 6000 kg, rotor diameter 12.8m with the smaller AS565 Panther, MTOW 4500 kg, rotor diameter 11.94m. I suspect it would be easier to operate the smaller Panther from a telescopic hangar on b2 Rivers. Panther is due to get SeaVenom /ANL.

Glass Half Full

Don’t know about Swordfish but UK company SEA has their Krait Defence System that would probably suit, . They illustrate it operating from a B1 in their marketing video and brochure. IIRC the Krait system was demonstrated in a NATO ASW exercise in Portugal in 2019 where it was fitted to and up and running on a small ship in about 2 days. Or of course there are Thales Captas 1/2 mission module options too.


I think my ideal would be the OPV Plus, but with one of the containers taken by 8 or 12 CAMM Sea Ceptor missiles, and with 4 ISSM launchers at the on the quarter deck. Keep the 40mm Bofors and the UAV. The UAV would be much much cheaper than a Wildcat, whilst still providing vastly extended surveillance capability. If the NSM is chosen as the ISSM then it will be a comparatively light weight addition and its IIR guidance system well suited to littoral warfare and would provide a useful land attack capability. The CAMM system would provide a very useful LAD capability, for example for tasks such as escorting tankers in the Gulf as well as self defence. The “soft launch” feature of CAMM would be very well suited to installation on a small ship like the OPV’s with very little chance of blast damage on launch and its ability to use the search radar on the ship and not a dedicated guidance set is another plus. The 40mm / 30mm mix would be perfectly adequate for policing operations and inner defence. Of course, the major factors would be cost, and have these ships got sufficient growth and top-weight allowance to accept these additions? If the answer to the latter is “yes”, then cost could be kept down if the CAMM system was containerised. That way, containers for the CAMM, the UAV systems and the SSMs (which are already treated as single-round “containers” anyway) would only be fitted to those forward- deployed ships in areas of the world where they were needed, and not to every ship. The only fixed upgrade would be the 40mm Bofors gun.


I’m torn on giving it CAMM. I can’t see any scenario where you’d want to use this under its own 25km+ AD bubble. However, the extended anti-missile range it would give would always be welcome.


Containerised CAAM though would be useful for various ships, not just B2’s. With its ability to accept radar from data link (as per Land Ceptor), it can even utilise radar from escorts. Someone somewhere must be working on it.


I’m reading this as a strong hint that the River 2s will not be spending their careers in UK waters. UK gov hiring additional civilian vessels for UK fisheries.

Steve Taylor

HMG is chartering two extra ships because it thinks there may be ‘trouble’ in the EEZ from our neighbours in the EU. That is because there are not enough RN (and Marine Scotland) hulls to do the job. The keys words being ‘may be’. This isn’t so the B2 can be deployed away from home to undertake taskings that achieves little. It is because we potentially have a REAL task here.


There’s an ideal hull for the job being chartered by the Royal Navy until the end of March, currently doing nothing. It wouldn’t be the first time a River class was recommissioned. So how about a big welcome back for HMS Clyde?

Steve Taylor

Yes. It is so obvious it sort of it hurts doesn’t it?

The UK has had far too few vessels patrolling ours seas for far too long. Every European state has a much greater presence in their own waters.


So I guess the big question is – why? As you state, the vessels were built for political reasons, but they were built with increased capability, which can be levered, but at the same time the answer cannot be “well, why not?”

The one actual requirement I can see, is to base 1 or 2 forwarded deployed in the Gulf. We never seem to have enough hulls in the Gulf when something goes down. I spent most of 10 years in RN on gulf deployments, frigates, destroyers, MCMV’s and even NP on an RFA, and so I can see the utility of an armed OPV as an adjunct to the “real warship” on station. If you need to escort a convoy, a T23 with a suitably equipped Batch 2 River as consort in company gives many more options; after all, a single ship can only be in one place at a time. A River B2 with either the 40mm or 57mm guns would have some self defence capability against air / missile attack, and add these to the midships 30mm’s (especially with Martlet) and you have an independently maneuvering asset, that can help confound small boat swarm attacks. With 2 armed RHIBS deployed, and maybe even that Martlet armed S100, and you have a very flexible adjunct to the on station frigate(s).

Of course if we could afford it, arm all 5 to the same standard, if not then maybe just a couple for that forward deployed mission. Of course HMG might decided post-Brexit Cod Wars need a 57mm………. hey-ho

Steve Taylor

The Government has always invested a lot of effort into the Gulf. But there has never seen to be any effort in procuring the right ships solely for that station in the post Cold War era. It should be recalled that the Tribal class sloops were designed and built for the Gulf. An upgunned River isn’t the right platform. I would say something 500 to 750tonnes with a fair turn of speed operated in pairs is what is needed. With a very simple aviation support ship like the RFA Engadine or even one of those ships that gets everybody really excited on sites like this, an Absalon to act as a flotilla leader. You would need 6 of the small ships, none of which to be operated singly (if possible) only in pairs. Of course HMG would never give the funding and there isn’t the imagination in MoD (N) to look beyond North Atlantic thinking.

Of course the best solution would be to just the leave the God foresaken region.


And send our merchantmen around the cape?

Steve Taylor

Last time I looked the Arabian or Persian Gulf was a bit of cul-de-sac.


Another rationale:
Now it is more clear that, there will be a gap in “number of escorts in service” from 2023 to 2027 (and later, depending on T26 schedule). If you count carefully, “number of escorts in hand of RN” is not that bad, a gap in 2023-2025.

# In 2025, both T31-hull1 and T26-hull1 will be handed over to RN. As RN currently can man only 12 escorts, and the crew is needed when it is “handed over” not when “in service”, counting escort number “in hand of” RN is more important than “in service” I think. Actually, as T26 hulls and T31 hulls coming at the same time, frigate numbers “in hand of RN” exceeds 13 around 2027 (and RN cannot man them).

Back to up-arming River B2, I think the only clear needs will be on the days of these “gap”. Counting “in RN hand” frigate number, the gap is in 2023-2025 for up to 2 hulls. Counting “in service”, the gap starts from 2023 and up to 4 hulls in 2026. So, if RN “needs” a hull to fill these gap, it is around 2023-2026 (may be -27, as T26 and T31 will be in service very late this year).

In this case, any up-arming must be reversal (can be configured back to current EEZ patrol optimized config). Also, it must not be expensive, because it will eat the budget and even delay the T31/T26 build. Then, the choices will be
1- adding LMM on 30mm turret at the bow (can remain, but not carrying in EEZ mode)
2- adding a UAV container on the waist (can be re-rolled in any ship)
3- adding 2 more mini-guns to make it 4 (same)
4- adding 2 LRAD (same)
5- replacing 16t crane with a 20 mm CIWS in stock for T26. (bring the crane back in EEZ mode)

If you look at River B2 carefully, the 16t crane is bolted on top of a ring. This ring is a top of a tube penetrating down to the second deck = stiff enough to hold a 20 mm gatling-guns shock. What we need for item-5 is to,
– bolt on a CIWS base-mount on this ring
– wire the power, data-link cable wired to CIC, and pipes for cooling water
– reserve a space for a console in CIC
Then if you bolt on the CIWS on this mount, and bolt on the console in the CIC, its done. Reversing is also easy.

I think this is doable, and efficient. Not sure, but maybe able to be sent to east of Suez, can counter Hoithi-rebels missile, and counter (peace-time) “terrorists-like” fast-boat attack as good as an escort (better armed for such close-in fight, but with less damage-control).

When T26 and T31 commissions, (up to 3) up-armed River B2 can easily reshaped as a specialist (super-efficient) EEZ patrol vessel, as is now.


Thanks for that link. The May 2027 in-service date for the first Type 31 is disappointing. We keep hearing that build schedules are stretched for budgetary reasons, but I’m starting to come around to NaB’s way of seeing things.

Why do you think the Royal Navy can’t man the frigates that’ll be handed over? Type 23s need more crew than either replacement.

2023 -T23: no change, unmanned anyway.
2024 -T23: +185
2025 -T23+T26+T31: 185+185-157-100 = 113
2026 -T23+T31: 113+185-100= 198
2027 -T23+T26+T31: 198+185-157-100 =126
2028 -T23+T26-T31: 126+185-157-100 = 54
2029 -T23+T31: 54+185 -100 = 139

Okay, it’s rough working in years, but at no time are the frigates arriving taking more crew than those being decommissioned in the same year or before. You can even carry on building another 4 T31s, one every year, increasing the total number of frigates to 17, and still not have a manning issue (that comes from the programme).

The in service gap is problematic, but up-arming the Rivers isn’t going to solve anything. We are better off making sure that all the Type 45s are in good nick by 2023, having the highest availability (including a Harpoon replacement). Napier can have no delays, and any money should go there. Especially if the Astute problem drags on.


Great chart. Thanks. If I shall add some comments?

– Now we have 12 manned (at various stage) and 7 unmanned escorts.
– Below, I assume
— if there is new T26, decommissioned T23 crew primary goes there, and if something left go to T31.
— If there is only new T31,decommissioned T23 crew goes to T31, leaving some.
— try to man as many T45, T23 as possible (*1)

2023 -T23: 12 manned, 6 unmanned, total 18
2024 -T23: 12 manned, 5 unmanned, total 17
2025 -T23+T26+T31: 12 manned, 6 unmanned, total 18, (185-157 = 28 left, but cannot fill T31-1)
2026 -T23+T31: 13 manned, 5 unmanned, total 18, (28+185-100-100 = ~0, T31-1 and T31-2 filled)
2027 -T23+T26+T31: 13 manned, 6 unmanned, total 19 (185-157 = 28 left, cannot fill T31-3)
2028 -T23+T26+T31: 13 manned, 7 unmanned, total 20 (28+185-157 = 56 left, still cannot fill T31-3 and T31-4)
2029 -T23+T31: 14 manned, 6 unmanned, total 20 (56+185-157-100 = -16, T31-3 filled, T31-4 and 5 not filled)

I think a 19-escort fleet can have 4 unmanned hulls (in long maintenance). So the goal is “15 manned”. It will be accomplished around ~2032, I guess.

(*1) Of course, you can priorities T31, to “increase” manned escort number. But it means putting T23 into “extended readiness” = manning 2nd Tier escorts by hollowing 1st Tier escorts. Not saying not going to happen, but I think the situation is to change.


Thanks for explanation. When you said only 12 manned, I assumed you meant Type 23s not all escorts. (I know you wrote escorts, I just read it wrongly.) That’s depressing. But it explains why you said they can’t man the new ones.

Stray Vector

Of those 15 manned, how many can actually be on station at one time? How many would be available in theater but not necessarily on station? What would remaining escorts be doing, training, in transit, etc.


As I understand, there is a rule of thumb, “3 for 1”. So, with 19 escorts, 6.33 will be able to be deployed, if proper operating cost and man-power are provided.

So, 6 in deploy, 6 in rest/training, and 7 in maintenance. When I say, “15 manned out of 19 hulls”, this means among the “7 in maintenance”, 4 is in Long maintenance.

However, RN escorts sea-going days have seen remarkable drop from 2010. Its average sea-going days was 120-140 days around 2010, but now it is 70-90 days a year. ~40% reduction. So, even if 15 hulls are manned, available for deployment will be 4 on average.

Here, when I say “6”, it means average 6 = sometimes 4, sometimes 8.
When I say “4”, it means sometimes 2, sometimes 6.

The latter is not much different from what we really see.

Stray Vector

Thanks, donald_of_tokyo

So if a carrier is deployed, 4 of the 6ish available escort would be deployed with her leaving ~2 for other duties. Or would it be 19 – (2 CV * 4 escorts ea=8)=11 escort. Then 11/3 = 4ish available?

Basically 8 escorts when a carrier is deployed, with 2 doing non-carrier related duties, and 4 doing non-carrier duties when a CV is not deployed. Yep, your math works out.

I saw a youtube video a couple of years ago where Chris Parry said the ratio was 3:1 and Bryan McGrath (USN) said the ratio was 4:1 ( I can see where forward deployment would get the ratio closer to 3:1.


This might be a silly idea but would it not be useful to stick harpoon on them when they are removed from service with the frigates. I know harpoon is end of life but surely it would be useful to defend against swarm attacks or to blow pirate skiffs up. The OPVs will never be used in significant warfighting but they could become a little more deadlier agains their intended targets by reusing existing equipment.


Those sorts of targets wouldn’t even register on the missiles guidance. That’s before you start considering whether keeping a missile in service well beyond its design life is a sensible, safe or affordable option. Let alone how you would fit the launchers to a B2.


Missiles have a EOL on more than technology. Fuel, motors, etc all have lifespans. UK did not invest in upgrades to Harpoon, unlike USN, RAN etc. eg RAN operate block 2 Harpoon, RN block 1. They also have minimum engagement distances (as do most missiles). While you could in theory program a cruise missile to turn around & fly back, I doubt it would be recommended in case it got confused as to intended target. It uses a 220kg impact fused warhead – not something to mess with.


We have a situation where we cannot yet man all of our destroyers and frigates, and the condition of some of those frigates is questionable as to whether it offers value for money to refurbish them for the small number of years service they have left. Why not retire 2-3 frigates now allowing us to fully man our remaining ships and use the money saved from their operation and refurb to upgrade the Rivers? I believe they could adequately fill many of the gaps until T26 and T31 come on line.
Whilst I understand the B2’s are not for high end duties, they could still be made to be very useful assets. I don’t think we need to upgrade all 5, maybe 3. I’m for an upgrade somewhere between OPV plus and Corvette. Let’s call it Corvette light. 57mm main gun, 2x30mm with LMM mounts, artisan radars and fire control from the retired T23s, a rotor wing UAV in one container and containerised CAMM or seaspear depending on the threat or mission in the other. I don’t see the need for ASMs. Enough to take out pirates, boat swarms, helicopters and UAVs, and give another Corvette a bloody nose.

David Broome

For me it’s a mix of options 1&2.

40mm main gun, a pair of 30mm with Lmm on the waist and a fire control system backed by containerised rotary UAVs. My one suggestion would be an 8-cell Spike NLOS Naval launcher that, with the UAVs, would give offensive punch to 30 kilometres.

Instead of a corvette, it turns the OPVs into gunboats with teeth, given it could be 10kms off a coast and strike a target 20kms inland. More so given it can deploy Royal Marines, where having such capability is complimentary.


I agree. With 40mm coming into RN service via T31 the barrier to adoption is lessened and the designed-in positions for containers port and starboard of the crane are perfect for flight operations (main container doors opening aft onto the flight deck) and a smaller personnel door could even be cut into the other end of the containers to allow easy crew access via the RIB deck areas which have doors back into the ship I believe.

I have one slight concern about talk of armed UAVs and that is regarding payload. Taking a Schiebel S-100 as a benchmark, that is quoted as having a maximum payload of 50kg ( which I assume excludes fuel. Wikipedia quotes a single Spike NLOS as 70kg. Even if it were half that though there still needs to be weight left over for a decent sensor package including very probably a laser designator. I know that twin Martlet has been shown on an S-100 but even there, with weight quoted at 13kg each, that only leaves 24kg over for sensors and something like Thales I-Master is 30kg on its own.

I can’t imagine that swapping sensor packages (between optical/laser and radar) when on board is a good or practical idea so either something with slightly more payload capacity but still able to be housed and maintained in a standard 20′ container is needed (my preference since I think an “S-100 Max” would have huge export potential and be a good thing for UK industry to develop) or some decisions have to be made between optical sensors (including laser designator), radar surveillance capabilities such as Thales I-Master, and weapons.

For armaments perhaps FreeFall LMM might be applicable against slow-moving targets and reduce weight.

On getting wide area surveillance capability without taking the weight hit of a radar package I wonder how Sentient Vision’s ViDAR is working out in practice (

There is certainly a lot to explore in this area and a lot to be gained from finding good solutions.

Mike D

As stated before a helicopter will always be more useful than a UAV and it does not have to be a Wildcat there are a lot of cheaper alternatives out there. One only has to look at the record of the Wasp in the Falklands war to see what a small helicopter can achieve.


What helicopters would that be that have folding rotors, high impact landing gear, designed for low level in a maritime environment.
There arent any of course in production anymore . The Wildcat is the smallest naval maritime helicopter. Its completely unrealistic to have another type in service and the Wildcat comes in 2 versions the HMA for the full anti sub work and the AH version for RM work, mostly on land but can be carried on deck.
Just looking at ‘headline ‘costs doesnt give an accurate picture of the unit cost as the MoD hides details by including development costs, production costs, and maintenance/sustainment all in one figure and often the yearly capital charge for assets that goes to Treasury included as well.


AS565 Panther, 1.5 tons lighter, 3ft smaller rotor disk. Its near relative, the AS365 is in service with the RN (contractor owned training). The AAC has 6x AS365 for SF.


As a variant of the AS Dauphin, if you have the data from Wikipedia , it says ‘unsubstantiated’
The AAC version is just a civilian version for use by the SAS ‘incognito’ within the UK.
If you just want the RN to buy civilian helicopters there is even smaller ones than that


Data is from Shephard Military Helicopter Handbook (April 2016)

David Broome

Then you need a hangar, spares and maintainers. Non navalised helicopters would have severe corrosion issues (airframe, engines and avionics) with manual folding/unfolding taking 30 minutes on a pitching deck with spray, wind and rain. Moreover, they are not designed for landing in sea states the RN need to operate in. To put three to sea, you’d need 9 in total (plus several for training). That’s a heck of a cost when rotary assets must be prioritised for the major escorts.

Thanks to upgraded fire control if there is an upgrade, in an emergency surge, the containerised UAVs could be landed and replaced by SSMs (other ships providing targeting), or containerised seaceptor or containerised CAPTAS 2 sonar with weight allowance for a triple tube ASW torpedo launcher. You can’t do that if a helicopter hangar takes up space.


I’d have thought that you could swap sensor packages aboard ship; the 20′ containers are big enough to use as a mini hangar. So if you wanted to use radar to gain sensor distance, at the expense of duration and range, you could.

AWHero is probably the next size up, with 85kg fuel+payload, giving six hours with a payload of 35kg. It’s not as mature as the smaller Camcopter or the V-200 Skeldar, but it might be the closest to your “S-100 Max” that’s near deployable.

David Broome

I would use the rotary UAV for surveillance and targeting. I am a big fan of the Spike NLOS that turns these vessels into capable small combatants in tandem with a 40mm main gun and a pair of 30mm on the waist with coaxial LMM (in a swarm attack, the 40mm has just 20 seconds of sustained fire unless the deck is penetrated. The 30mm and LMM creates layered defence. Crucially, this combination is practical and affordable.


As some have already said, I would be hesitant to put too much money into the B2s. Not because I’m fearful of them being sent into a hot war, but because I think the T31 should get any extra money going (primarily for ASM cannisters). Assuming that there is money for both, I would probably still spend the cash on something else like personnel and retention, a fleetwide UAV replacement for Scan Eagle, a platform agnostic containerised ASM, or the helicopter fleet (to name a few of what I see to be greater priorities).
But, assuming I absolutely had to upgrade the B2s in some way, the suggestions at the bottom to middle of the pile seem about right. Mini-corvette is too much, the worst I can see a B2 getting involved in is a running gunfight on the Strait of Hormuz, likely backed up by a T23/26/31. The comparison with the Thai Navy River class is a bit tricky, as by displacement they are larger than the Thai corvettes currently in service, and the same size as half of the frigates currently in service (admittedly the older ones). When looking at the armament therefore, I assume that the Thai navy are considering these as “full size” surface combatants and arming them accordingly. Pretty much every vessel in their fleet runs the 76 Oto, so I imagine they have a bulk buy discount and can justify a lot of commonality savings by using it, same with the Harpoon.
I’d be tempted to keep the DS30 at the front (provided it got the LMM rail), with an additional one on each side (also with LMM if possible); this keeps commonality of ammunition type, which would I imagine be a benefit on what is a relatively small vessel. I just don’t think it’s worth putting anything bigger on it.
As far as other stuff goes, I’d not fit anything other than a telescopic hangar, as I’d want to still be able to carry containers. I’d hope to find somewhere that I could put a UAV into, something with similar capabilities to the latest Scan Eagle variants that the Australians are using with the wide area search and track system. I like the idea someone had of using up the old Artisan from the T23s, if it doesn’t ruin the (apparently impressive) sea keeping capabilities of the vessel by being too top heavy. The weather can get pretty horrible in many of the areas these could be expected to operate.
I’d then look into containerised surface warfare systems that could be used across the fleet, whether that be NSM or even something smaller like Brimstone.
I would definitely not stray into area air defence or ASW; they are way too specialised and expensive and a B2 isn’t built for it.


57mm maker sence along with 2x 30mm plus the camcopters fitted with martlet. Fitting the army loader from the army version of sea ceptor would be useful if fitted to cam copter iso container. That would leave iso container for MCM or usv’s.


In many ways I am as I wrote in an earlier post all for up gunning the Batch IIs, then again Mmmmm, maybe not. It really does depend on where HM Government wants to deploy these ships. They are first and foremost in there current configuration Fishery protection vessels but with the lack off hulls, and manpower the Government might decide to use these ships in a more aggresive role. If this is the case then they would act like a trip wire and should be armed in such a way that although not threatening to other nations they would show intent in being able to defend themselves against low, low-medium level threats.
However if the Government intends to use them in the role that they are currently equipped for then I would make a diffrent suggestion, remove the Batch 1s and IIs as well as the Archers from the Royal Navy altogether.
The UK Government has at its disposal for EEZ patrol the following, 3 Batch I, 5 Batch II, 16 Archer class (RN), 4 42m Revenue Border Cutters, 1 Telkka Borber cutter, 6 Coastal Patrol RIBS (Border Force) and 3-4 Scottish Fishery Protection Vessels. Why not put all of these into a single Coast Guard Service. They could still be used for training, they would have a combined headquaters rather than at the moment a RN headquaters, Border Patrol headquaters, SFP headquaters. There seems to be lots of headquaters costing money and manpower, there is no true cost to the treasury as the budget is spread over several forces, the RN could use the savings for investment into the fleet of war and people retiring from the RN could go into the new Coast Gaurd force if they want to. Ive called it a Coast Guard force for the want of a name it could be Border Enfocement Force or whatever but you get the idea. Just by combineing everything under one roof the UK would have 38 boats to protect UK waters without any increase in budgets or numbers, each boat should have police, customs officers, RMs etc on board and the force should be giving the power of inspection/detention and arrest. The current revenue cutters should have the same armerment as a Batch 1, the Archers should have their 20mm guns installed there hanging about somewhere in a store room and the Patrol RIBS equipped with GPMGs.
By taking the OPVs and the Archers out of the RN fleet lists the Government can then see what they really have to do the job world wide rather than getting away with summer shoes in the middle of an artic winter, which is what we do now. An example is the deployment of an OPV to the Caribbean, what use is it going to be, its not fast enough to catch a drug smuggler, it does not have a lot of capacity in the humanitarian aid situation, it can’t embark a helicopter for long periods of time so there is no real air support, it just shows the flag and gives the government the right to say to the people that we have a ship deployed in the region. Which is true, but its of no real use.
So what does the Government want the MoD and the RN to do with these ships. Operate on a world wide basis, if so then uparm them, For UK waters then put them togtether with all the patrol boats of the UK and form a single force with the authority of warrent. If it is the later it should not mean that the RN budget is cut.

Stray Vector

This is probably the best recommendation of the whole thread. I’d still up-gun the River B2 and keep them in RN though.

David Broome

How about keeping them under the white ensign and reforming the Home Fleet?


What happened to the Lynx helos? Do they have any miles left in them? Could they be pressed into service on say 3 of the batch 2 Rivers modified with a telescopic hangar? Regardless of any up-arming wide area surveillance is surely the capability game changer for interception of drug runners or pirates. Even as a temporary measure until the T31s come into service.

Mike D

Just thinking there must be a few serviceable ex RN Lynx with GPMG, spares, and sailors qualified to fly and maintain them. For the cost of swapping the R2 crane for a telescopic hangar you would get a quantum leap in anti piracy / drug smuggling patrol capability. Let’s face it, you are never going to fire your Martlets or 40mm at a dhow.
Granted the crewing and maintenance of the lynx will not be free but it’s reversible, temporary cost, as is the hangar if you do it right.


BAe built the 62 metre FAC for the Hellenic Navy. I would have thought a slightly scaled back weapons fit would be ideal for the Rivers. The FAC is armed with a 76mm, 8 x Exocet and 2 x 30mm.
The rivers certainly don’t need Harpoon but a weapons fit of; 57mm, Sea Spear and 2 x 30mm with LMM option would give plenty of bite


I agree batch 1s should be kept and used as a coast guard/customs branch of the RN with retired and merchant seamen aboard with the exception of the key personnel on radars, weapons and boarding parties, these are deployed to cover irish sea to top stornaway, one for ern ireland through south and english channel islands & one in the north sea. this includes bringing HMS clyde back into the fold to cover north atlantic perhaps based in faroe islands or sullem voe area. At least 3 batch 2 up gunned to the plus with 40mm, 3x 30mm and camcopters with martlets to extend range one in the caribean, one in the med/black sea and kept back for general duties, the other 2 batch 2s should get the 57mm, 2 x 30mm camcopter with martlets one being based in falklands the other in the north sea to keep russians at bay.
as the type 31 will now be late I would propose 3 new batch 2.5s built with a boxed in are from rear of the bridge to the flyco to create 2 multimission hangers either side of the stack (stack to be raised to clear hangers) ribs relocated to the roof either side of the stack, hangers to have doors to allow 20ft iso containers or wildcat to fit, sides to have shuttered openings to allow armed usv or minesweeper boats to be launched, CMS & radars upgraded to tacticos etc up gunned to 57mm, 2x40mm 12 seaceptor aft of the stack between hangers, these are to be forward deployed to bahrain, singapore and indian ocean and if they can be in service by 2023 will give us 4 years to ready crews for the type 31s and will compliment the type 31s when available as we will probably lost 4-5 type 23s by then, hopefully crews from these boats will be available to man these boats on a rotational system.

Meirion X

New Batch 2 River OPVs, would take just as long as Type 31 frigates to be built and bring to service


These are constabulary vessels, as soon as the RN starts bolting stuff to them Our political leaders will consider them warships and insist they are treated as such. The pressure will then be to send them into harms way, at which point all of the hard lessons of the Falklands war would have been forgotten and we will loss these ships and their crews if the worst happens.

The RN needs to hold to its policy of making sure it OPVs are clearly nothing more than cost effective constabulary vessels and should not be facing more Greater threat that a drug dealers fast boat, modern pirates or a hard day in the North Sea.


Very well put.

Humpty Dumpty

Jonathon: I agree with your first point, but for fisheries protection I’d say the Rivers are overarmed (even the Batch 1s), surely GPMGs and armed sailors are plenty good enough? Much cheaper vessels could do this job. To catch drug or arms runners, the Rivers are too slow. For naval anti-terrorism work, they’re probably OK for some situations (especially with Royal Marines or SBS on board). For anything else they’re underarmed. Uparming noisy diesel-powered Rivers though and sending them anywhere where there’s likely to be subs and they’ll be sitting ducks. Same goes for anti-ship missiles. The only thing Rivers could realistically be uparmed for is to deal with fast attack craft in areas where there are no subs and no anti-ship missiles. Otherwise you need Type 23s and/or Type 45s. Even Type 31s couldn’t survive in areas where there are subs because they too will be diesel-powered and noisy, plus they will have no sonars, no SSTD and no VL-ASROC. Will they even have Merlin HM2s? Plus the Type 31s proposed anti-air capability isn’t great (just 12 CAMMs) and the Bofors 40mm is out of ammo in just 20 seconds.


The Rivers B2 are definitely underarmed (the whole article is about upgrade options). The 40mm has a maximum range against surface targets of 12.5km, which is pretty well the horizon when viewed from an OPV. The fact that you probably can’t hit them at that range doesn’t matter (it was a warning shot wasn’t it). While a pirate etc fast boat can possibly outrun an OPV in the short term, it can’t in the long term & it definitely can’t outrun a 40/57mm. If you are close enough that they can see you, they are in trouble if you wish to push it. The problem with operating the Rivers against pirates in places like Somalia is that AShM have been fired at naval ships from groups in countries relatively close by. A 2,000t navy ship is possibly big enough to attract unwanted attention. Yes, the 40mm only has enough ammo for 20 seconds. If you haven’t shot down that AShM in less than 20 seconds from when it was in effective AAW range, then it has quite likely already hit you (or missed you as the case may be). If you are operating close to shore & someone starts firing RPG‘s or mortars at you (not exactly rare weapons in some areas), a 30mm can do little about it if you cannot see the shooter. Air burst is the poor mans indirect fire, something the 40mm is capable of. The 57mm is actually capable of indirect fire but is considered a secondary function.

Humpty Dumpty

The Bofors 40mm would be a good addition to a River. Other options are the Oerlikon Millennium Gun or the Thales RAPIDSeaGuardian. They can all fire smart ammo, although my preference is the Oerlikon Millennium Gun which can send out a cone of 152 tungsten projectiles and which I’d have thought would be very likely to destroy any missile it’s fired at. Unlike Phalanx which fires bullets, the Millennium Gun firing airburst ammo is more like a shotgun and so more likely to hit its target using fewer rounds.
As for pirates in fast boats, they can’t outrun a 40/57mm true (or a helicopter or UAV for that matter), but unless fired on first, wouldn’t the ROEs prohibit a River from firing on pirates? The Baden-Württemberg-class frigates have water cannons, which is a good non-lethal way to deal with pirates.
As for anti-ship missiles, it would make sense to fit Rivers with MASS and/or Siren decoys and 16 CAMMs in an ADL launcher (which can be replenished at sea) to complement the Bofors/Millennium Gun/RAPIDSeaGuardian.
Imo it would make sense for any gun fitted to a River to be deck-penetrating and reloadable by means of an auto-reloader. Do such guns exist? When I said that the 40mm could be out of ammo in as little as 20 seconds, I had FIACs in mind, not anti-ship missiles. Remote-controlled or suicide FIACs are a possibility now. In the future, drone FIACs will increasingly be a threat, so the more ammo a ship has the better. That’s why it would also be wise to have DS30Ms enhanced with LMMs as well as Schiebel Camcopter S-100s with LMMs.
As for RPGs and mortars, I’d have thought a Millennium Gun could take them out. I mean MANTIS, which is essentially the same weapon but land based, is expressly designed to take out rockets, artillery and mortars.

Last edited 7 months ago by Humpty Dumpty

Currently, these vessels are nothing more than metal flags and virtually useless against more sophisticated pirate/drug delivery gunboats. The latter will be an increasing problem for the RN globally, and the upgrades suggested in this article should be given the most serious consideration.


This is all very interesting (I always enjoy the upbeat articles) but it baffles me as to why Royal Navy procurement is in such a mess. Here we have a department trying to squeeze more capability into a relatively small OPV. Another department in finding ways to reduce the capability, on paper, of a much larger T31 frigate. Switch departments! Don’t they communicate? The navy might then, finally, have one vessel that reaches its full potential from the outset. Yes, I’m being facetious but why do they always start with the weakest option and then spend millions on development, causing delays in building or a vessel’s withdrawal from service for months, maybe years. The underlying consequence is that the navy will continue to shrink. Our potential foes must be very content. Our allies must despair of a navy that was once the gold standard for navies throughout the world.


I must say that having the .40 mm bofors seems a no brainer to me. It is a lethal weapon and of itself make the OPV a patrol vessel with fangs. The Falklands is a quiet place at the moment, but that can change.
All the other weapon systems while desirable, would meet head on with the budget. The .40
Is a proven weapon and seems the most feasible from a money standpoint.

Humpty Dumpty

I agree about the 40mm Bofors, because although FIACs aren’t likely to ever be an issue around the Falklands, anti-ship missiles fired from aircraft or subs could be if there’s ever a Falklands Part 2. I think it would also make sense to fit any River operating there to be fitted with decoys like MASS and/or Siren and some CAMMs, preferably in ADL launchers that can be replenished at sea (16 CAMMs per launcher). I’d also like us to start building diesel-electric subs again. They’d be perfect for home waters and Falklands defence. An uparmed River equipped with a Swordfish towed array sonar or Krait Defence System and a permanently embarked Merlin HM2 would provide a pretty decent level of defence in the Falklands, especially if escorted by an AIP sub. If a Poseidon patrol aircraft was based on the Falklands, then all the better.


These ships are going to be worked into the ground, just enforcing the fishing perimeters in anything like an effective way is going to be a stretch. To be honest I think they will be lucky to get a new coat of paint in the lifetime let alone anything else.
I think we need to be more concerned about the 31 and the 26 and their loadouts and capabilities.

Humpty Dumpty

I don’t see the point of using Rivers for fisheries protection when far cheaper vessels could do this job just as well. Even the Batch 1s are overarmed for this task imo and I don’t see the sense of the Royal Navy doing this job anyway. It would make far more sense imo for us to set up a nationwide organisation to enforce fisheries protection rather than use the Royal Navy for this job.


Given the impact of COVID-19 on HMG finances I suspect turning the B2 Rivers into the primary RNs permanent forward presence outside of the Gulf is going to have to be given more priority, as the older GP T23s will have to be decommissioned quicker to fill any funding gap.

I’d go for “OPV Max”, but call them what they are Sloops.

Humpty Dumpty

I don’t really see the point of the River OPVs. They’re too expensive and overamed for fisheries protection where far cheaper vessels with GPMGs and armed sailors could do the job just as well I would have thought. They’re too slow to catch arms or drug smugglers, who will use the fastest vessels they can get their hands on. And they’re woefully underarmed for any kind of warfare.

Even if you uparm Batch 2 River OPVs, you’re still left with a noisy diesel-powered vessel. Send them anywhere where there are likely to be subs and they’d be sitting ducks. Equally send them anywhere where they are likely to be targetted by anti-ship missiles and I can’t see them surviving for long. At the very least I’d want uparmed Rivers to have some anti-air missiles (and preferably in ADL launchers that can be replenished at sea). Relying solely on guns to shoot down anti-ship missiles is idiotic. Even if the guns CAN shoot down anti-ship missiles (which I have serious doubts about), unless the guns are deck-penetrating to enable reloading, they could be out of ammo in as little as 20 seconds. Plus layers of defence are always best so: anti-air missiles, guns firing smart airburst ammo, decoys and ECM. But all that would make the Rivers too expensive, so why even bother?

Nick Bowman

The combat capability of these ships could be considerably enhanced in a hurry and for not much money. Purchase Starstreak II in 6-round naval launchers for a 7km/16k foot air-defence capability. Add Martlet to the existing 30mm and a telescoping hanger large enough for a Wildcat. OPVs equipped in this manner could operate in the Gulf in any situation other than all-out war.


Having just read an article on palletised weapons the US are trialing this could have far reaching benefits to the RN. Imagine the Merlin/chinook with pallets of deployable weapons in the back that can’t fit in/on the F35s. The F35s identify target and the Merlin’s operatining under the fleet air protection zone launch the munitions and guided by the F35s. As the Merlin can land and refuel on the back of any of our escort fleet this could greatly extend the radius of weapons cover and basic cost of buying these new pallets to load with a couple of storm shadow anti ship missiles