The 30mm Automated Small Calibre Gun is carried by the majority of vessels of the RN surface fleet. Here we look in detail at this ubiquitous weapon system.
Background
The naval anti-aircraft cannon that can fire explosive shells can trace its roots back to WWII. Swiss-designed Oerlikon 20mm and Swedish-designed Bofors 40mm mounts were used throughout the war and were still in RN service with minimal modifications in the 1980s. The 1982 Falklands war demonstrated the RN’s urgent need for more capable air defence weaponry.
The BMARC (British Manufacturing and Research Corporation) offered its GCM-AO3 twin mount to the RN in 1973 as a candidate for equipping the Type 42 air defence destroyers. The tight budget, a fixation with guided missiles and top weight limitations meant no orders were placed, but in late 1982 the design was still available and went into immediate production.
The GCM-AO3-2 provided stabilised rate-aided gyro sight for the gunner, which much improves accuracy and the twin barrels delivered a combined 1,300 rounds per minute. The mounts were hastily fitted to the Type 42 destroyers and the LPDs until sufficient Phalanx CIWS mounts were available. Subsequently, the Bach I and II Type 22 frigates also received them, but as they were equipped with the Sea Wolf point defence missile, the urgency was not as great.
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Gunners on a Type 21 frigate during the 1980s operating the same weapon used by their grandfathers in the war – the Oerlikon 20mm Mk 7A. This was a crude but reliable weapon with a rate of fire between 500-800 rounds per min. The cylindrical drum magazine was changed by hand. -
The Bofors 40mm L/60 on the electrically-powered Mark IX mount could fire up to 120 rounds per minute. This weapon entered service with the RN in 1941 and was still in widespread use in the 1980s. One of the mounts on either HMS Fearless or Intrepid managed to shoot down an Argentine A-4B Skyhawk during the Falklands war of 1982. (HMS Brazen, 1984). -
Stop-gap: the BMARC GCM-AO3-2 mount for twin Oerlikon 30mm, each capable of 650 rpm. These were fitted across the fleet in the mid-late 1980s to replace the 40mm Bofors and provide better close in air-defence or until more Phalanx CIWS mounts were available. -
The successor to the Mk7, the Oerlikon 20mm/85 KAA cannon GAM-BO1 mounting. In service since 1983, this simple, manually-aimed weapon has a rate of fire of up to 1,000 rounds per minute and remains in use, fitted to the LPDs, the survey vessels and Batch 1 OPVs. (HMS Chatham, 2010)
To replace the rather motley collection of Bofors 40mm, Oerlikon 20mm and the GCM-AO3 with their differing ammunition, training and logistic requirements, the RN opted for modern single 30mm cannon. The LS-30B mount was designed by Laurence Scott Ltd and entered service with the RN in 1989 carrying the Oerlikon KCB 30mm cannon, the system was designated in service as the DS-30B (Laurence Scott having been taken over by MSI Defence Systems Ltd). This mounting and it’s modified descendent, the DS-30M Mk II remain in service today.
Seahawk
The mount has a modular central yoke which and it can be configured for use with cannons between 25-40mm. It is a highly flexible design that can be customised with different ammunition arrangements, gunner’s cabin, sights, sensors or co-mounted weapons such as small missiles or other light guns. MSI-DSL markets the mount as the ‘Seahawk DS’ family but this designation is not officially used by the RN which instead refers to the whole system as the Automated Small Calibre Gun (ASCG) or more commonly, “the 30mm”.
The mount is gyro-stabilised, electrically operated and self-contained with a choice of control modes and sights. It is designed to have a low magnetic, radar and infrared signature, be reliable and easy to maintain.
These guns can be directed and fired in three ways. When in local control, (LOCSIG) a gunner aims and fires the gun while sitting in the cabin on the right-hand side of the mount. Should the electrical supply, gyro stabilisation and heading inputs from the ship be cut off or interrupted, a backup battery and manual operation by the gunner on the mount can keep the weapon in action. Alternatively, it may be remotely controlled (REMSIG) from consoles on the bridge or in the operations room. The operator aims the weapon using laser, TV and infrared imagery from the Electro-Optical Directors mounted away from the gun on platforms high on the ship.
In many situations, directing the gun using the EOD has many advantages over the naked eye of the gunner sitting on the mount, particularly at night or in poor weather. (See previous article about EODs). In AUTSIG mode, the DS-30M can be aimed by the EOD which can autonomously track targets and provide a fire-control solution directly to the mount.
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The shell can just be seen leaving the barrel – travelling at approx 1,000m per second. This is HMS Kent in 2008, like all Type 23 frigates she was subsequently retrofitted with the DS-30M Mk II mount. -
Spitting fire – The Type 45 Destroyers carry two DS-30B mounts on dedicated platforms, port and starboard. The mount weighs 1,200 kg with ammunition and can fire up to 650 rounds per minute. There is stowage for 160 rounds on the gun – just under 15 seconds continuous firing. -
The 20mm Phalanx CIWS and the 30mm combination provides a formidable additional line of anti-aircraft defence. (HMS Duncan, 2018). -
RFA deck department personnel conduct gunnery exercises onboard RFA Cardigan Bay while deployed in the Arabian Gulf. -
Down the barrel. (HMS Ledbury, 2019) -
Conducting operator confidence checks while alongside in Faslane. (HMS Blyth, Nov 2020) -
Ammunition belt used to feed founds into the gun (HMS Monmouth, Dec 2012) -
Ammunition feed is prepared (RFA Wave Knight, 2017). -
Gunner looks through the detachable reflector gun sight which projects the aiming point and reticle superimposed on the field of view. A basic optical sight is provided as a back up (HMS Monmouth, June 2004). -
(HMS Monmouth, June 2004) -
Conducting a live firing using the Quick Point Device (QPD), the laser pointer is aimed manually form the bridge wing illuminating the target for the gun controller to engage. (HMS Dragon, Apr 2013). -
The DS-30B Mk I
The original DS-30B is still the most numerous mount in RN service and as of 2003, the RN had purchased 72 systems. They are equipped with the Oerlikon KCB 30mm cannon, a design based on the Spanish Hispano-Suiza HS-831 developed in the 1960s. Oerlikon Contraves subsequently acquired the HS design and sold the weapon as the Oerlikon KCB. The KCB designation is derived from the Oerlikon naming system for guns. The K is for Kanone (gun), the second letter denotes calibre, C being 30mm and the third letter is for the gun model. (Oerlikon Contraves has subsequently been absorbed into the giant Rheinmetall Defence Group).
The KCB 30mm was conceived as an anti-aircraft weapon. It is a ‘traditional’ cannon, using propellant gas to unlock the bolt and breech during the firing cycle and can be clip-fed or belt-fed. It has a relatively high rate of fire, of up to 650 rounds per minute and an effective anti-aircraft range of about 2.75 kilometres. Firing horizontally it can reach 10km and the mount can traverse at up to 55º per second. The Mk 1 mounting is easily distinguished from the MK2 by the square barrel mount and boxed ammunition chute but is virtually identical in weight and dimensions.
Spurred by the terrorist attack on the USS Cole in 2000 and increasing awareness of vulnerability to asymmetric attacks, the RN began the littoral Defensive Anti-Surface Warfare (ASuW) upgrade programme. This included a requirement for a more modern cannon that emphasised accuracy and reliability over rate of fire. The KCB 30mm is ideal for putting lots of metal into the air to defend against high-speed aircraft but is less well suited to smaller, slower and sometimes hard to classify targets. Defence against fast attack craft and ‘swarming’ threats in the littoral areas which may include small boats, and jet-skis, perhaps armed with small missiles, rocket-propelled grenades, heavy machine guns or explosives. In the past decade, the evolving threat from UAVs and USVs now puts even greater emphasis on accuracy and automation.
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The mount in REMSIG mode being operated remotely (HMS Somerset, 2009). -
(HMS Kent, 2020) -
(HMS Trent, 2019) -
The linked rounds pass up from the pannier on the right through the flex chute to the receiver on the gun breech. The flexible chute allows the gun to elevate between -20º to +65º (HMS Sutherland, Oct 2011. Photo: Navy Lookout) -
Five-pannier LMM launcher in place of the gunners cabin – trialled on board HMS Sutherland in July 2019. This demonstrates the adaptability of the mount. The lack of official comment following the trial suggests it was not regarded as a great success. -
An interesting alternative configuration of the Seahawk DS A1 mount offered by MSI-DSL (Not in service with the RN). The Bushmaster is duel-fed with ammunition from left and right panniers. The gunner’s cabin is replaced by controls directly mounted on the gun, although the weapon is typically remotely controlled. Note the addition of angled panels to the mount intended to further reduce radar signature. -
The business end. The barrel recoils 380mm back when fired and the empty cartridge cases are ejected forward from the tube on the left. (HMS Tamar, Sept 2020. Photo: Navy Lookout) -
The DS-30M Mk II
In 2005 the MoD awarded MSI-DSL a £15M contract for 26 DS-30M Mk II (ASCG) systems, initially for retrofitting to the 13 Type 23 frigates. Land-based trials were conducted at the Eskmeals Range in Cumbria before the first mountings were fitted to HMS Somerset in August 2007.
There are some modifications to the mount but the main difference between the Mk I and Mk II is a completely different cannon. The ATK Bushmaster II Mk 44 was developed in the US (Northrop Grumman bought out ATK in 2018) and is an exceptionally reliable chain gun. This type of weapon does not rely on the occasionally unreliable firing of the previous cartridge to cycle the action. An electric motor is used to drive a chain that moves the bolt assembly that loads, fires, extracts, and ejects the cartridges. In the event of a misfire in a conventional gun the gun has to be manually cleared which can take even a well-trained crew several minutes. A chain gun will continue to fire regardless, automatically ejecting a misfired cartridge. Theoretically, the rate of fire could be completely variable but the DS-30M has 2 settings – slow or fast and can be set to fire single rounds or continuously (maximum 200 rounds per minute).
The Bushmaster offers precise round control and is easy to maintain with low-through-life costs. Already proven in combat on Armoured Fighting Vehicles (AFV), the selection of the Bushmaster was a low-risk option. Most significantly rounds have a low dispersion rate offering better accuracy than the KCB, with an effective range of 2km and a horizontal maximum range of about 4km.
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The Northrop Grumman Bushmaster II Mk 44 30mm is part of a family of chain guns originally developed for armoured fighting vehicles but adapted for naval use. The gun itself weighs 154.6 kg and is 3.4m in length. -
(left) Underside and (right) the gunners-eye view. (Photo: Navy Lookout) -
The gunner’s control panel. The black safety catch handle on the left is pulled up and locked for firing and the trigger is on the front side. The selection switches for single/rapid and slow/fast rate of fire are above. The elevation and bearing indicators are top and centre with status indicator and safety switches below. The thumb joystick on the top of the handle on the right is used to train and elevate the gun. The sockets bottom left are for the communications headset and the power supply for the gunner’s heated suit for use in cold weather. -
(Left) There is a control console for each weapon on either side of a Type 23 frigate’s bridge. (Right) There are also identical consoles in the operations room (HMS Somerset, 2010). The controls are very different to the gunner’s panel on the mount as this is integrated with the Electro-optical director (EOD) which provides TV images to the operator. -
The Bushmaster II has a unique dual-feed system which allows the operator to select different types of ammunition for use against a variety of targets but in RN service, only a single feed is used. In this image, the flex chute has been removed but when the gun is in use, the chute is connected into the lower receiver socket on the breech. (Photo: Navy Lookout) -
Close up of the right side breech. The used side-stripping cartridge links are discarded from the opening at the top. The bottom (brown) section contains a chain which is moved by a sprocket in a rectangular circuit. One link of the chain is connected to the bolt, moving it back and forth to load, fire, extract, and eject cartridges. (Photo: Navy Lookout) -
The breech top slides back and can be lifted off to inspect the chain and bolt assembly below. -
The 30mm HE rounds weigh 0.735 kg each. -
30mm cartridges and links on deck after a gunnery serial. -
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In 2016 the RN ordered another 12 Mk II mounts from MSI in a £16.5M contract that would see deliveries and support over a 5-year period. In addition to the Type 23 frigates, the 5 new batch II OPVs carry the MK II and both QEC aircraft carriers will receive 4 mounts. HMS Queen Elizabeth is due to receive her outfit in early 2021, prior to her first operational deployment. It is possible they will be REMSIG and AUTSIG-only and not have gunner’s cabins for local control.
The MK II will also be fitted to the Type 26 frigates, probably using refurbished mounts removed from Type 23s as they decommission. The Mk 1 mount is fitted to the Type 45 destroyers, the minehunters and some RFAs. Although there is space available, it seems unlikely the Type 31 frigates will be fitted with either 20 or 30mm cannons as they will have two automated Bofors 40mm Mk4 mounts.
| Vessel | DS-30B Mk 1 | DS-30M Mk II | GAM-BO1 |
| QEC Aircraft Carriers | 4 | ||
| Albion Class LPDs | 2 | ||
| Type 45 Destroyers | 2 | ||
| Type 23 / 26 Frigates | 2 | ||
| OPV Batch I | 1 | ||
| OPV Batch II | 1 | ||
| Sandown Class Minehunters | 1 | ||
| Hunt Class Minehunters | 1 | ||
| Echo Class Survey Vessels | 2 | ||
| Bay Class RFA | 2 | ||
| Tide Class RFA | 2 | ||
| RFA Fort Victoria | 2 | ||
| Wave Class RFA | 2 | ||
| RFA Argus | 2 |
The table above shows the distribution of the 3 cannon types across the fleet and the number of mount positions per ship. It should be noted that not all vessels are fitted with these weapons at all times, particularly the RFAs. They are usually removed for refurbishment and/or use on other ships during major refit or when a ship is in low readiness.
I’m getting all nostalgic!
7A, Bofor, Gambo, Twin and Single 30 at some point during my time I maintained and fired all of them.
The Twin did have remote control capability wired into the mount as standard but the RN never adopted it or connected it up.
A point to note on the mounts with seats(Twin and Single 30mm). The impulse noise from the cannon is so high that all previous and current ear protection ( In ear plugs with Protectors/Attenuators over the top, an anti flash hood and then a helmet) is rendered useless and the noise the Gunner is exposed to is way above the H&S limits and cannot be mitigated or attenuated to an acceptable safe level.
The number of Gunners and Maintainers (Me included) with hearing loss (in left ears especially) is huge and was another less publicised factor in going to remote operation.
Now, with the remote mounts the hearing loss issue is thankfully going away.
Say again, over! 🦻
Excellent article. Many thanks. The RN also seems to be making more use of the 50cal HMG – especially on vessels deployed to the Gulf.
Do these guns provide timed air-burst?
No.
Point detonation only. It’s not worth doing air-burst from anything under 35mm in practice (and even then its marginal). Basically the shell size below 35mm doesn’t have enough space for the fusing, sufficient explosive and shell casing to have decent fragmentation.
Realistically you need 40mm + to make it worthwhile.
One thing not covered in the article is the option to upgrade the Bushmaster II (mk44) from 30mm to 40mm (40×180) by changing a few parts. This gets you more punch than the 30mm, the needed extra size for reasonable air burst & will still fit the current turret (provided the turret can handle the extra recoil). It is also the cheapest way to upgrade the firepower of the River B2’s.
Northrop Grumman Delivering Next Generation Ammunition Capability to US Army | Northrop Grumman there is now a 30mm starburst. So could this be a cheap CIWS with some radar guidance from main radars on batch 2 etc?
It’s a small bursting charge. Has some utility against UAS. But against missiles or aircraft? Not so much. Trying to do to luch with too little.
The smart move would be to move to the Super40 round on the MSI DS-30M.
Another very well researched article.
An excellent and as usual, very informative piece.
Congratulations on the “new look” Lookout.
Excellent article. Thanks.
Greetings all
The Mk.44 is a great weapon and it saddens me to see the Army not adopting it for their AFV fleet. I have spent the last 15 years working with chain guns of differing calibres and uses but they all look virtually identical on the inside.
There are some more pros and cons that I would like to add.
Firstly toxicity, all propelling gasses leave the barrel, therefore none leak back towards the crew operating the weapon, this may seem a tad soft but its a H&S nightmare.
As it was already alluded to, you can change the rate of fire of a chain gun by changing the amount of power going to the drive motor, this is a useful option when switching between ground and air targets. This can also be done with a conventional gun but its a pain in the ass to add artificial friction to the gun mechanism.
Bolt operation. Probably the greatest benefit of a chain gun is the fact it can fire both open and closed bolt. You get the benefit of open bolt operation, better cooling and rate of fire or you can switch to closed bolt operation for more accurate fire.
Clean firing. No one likes cleaning weapons and there is nothing worse than scrubbing carbon off the workings of a gun, chain guns fire very clean so a quick wipe of the gun body and your good to go.
The bad points. It was mentioned that a misfired round would simply be extracted and ejected due to not needing propellant gasses to cycle the weapon, this is a relevant point but misfires are less of a problem these days due to better ammunition manufacture. Most stoppages on automatic cannons are caused by a problem with the feed mechanism, and when a chain gun feed mechanism goes wrong, it goes very wrong.
Great article, I love the vid of a kid pointing a 30mm at some civvies.
The new Anglo-French 40mm is a technical marvel. But an utter waste of money with expensive ammunition. We should as you say just have bought something off the shelf. As with all joint ventures the French will benefit the most.
The 40mm CTA is a beautiful piece of engineering, I could (and unluckily for some of my students do) talk about it for hours. It’s just the wrong tool for the job, it was selected based on bogus data and false claims, but we are stuck with it now.
Expensive is an understatement to say the least, a Rolls-Royce is expensive, CT40 APFSDS-T is positively extortionate.
We selected 120mm L-30 for Challenger 2 and paid the price in lack of ammunition commonality, we swore never again, we clearly don’t learn.
Yes. 🙂
I remember reading how the small size of the ammunition would allow much more to be carried and thinking space due to cost would never ever be a problem.
There are just so many options on the market we could have purchased. Even watching old videos of CV90 trundling around pooping of 40mm Bofors makes me tad angry as that old campaigner of gun would have been a lot better for us.
How much money could the Army have saved for its woeful vehicle programmes by being more pragmatic? (Saying that I am still trying to fathom why the refurbished Warrior needs a cannon. Why not a RWS with a HMG and / or 40mm grenade launcher and no turret?) But we buy woeful Ajax instead……….Again as I often with naval matters I look to the wonderfully conducted Australian vehicle programmes. They will probably end up buying Lynx to compliment their Boxers…
Saying all that I think the French Jaguar cavalry vehicle is a marvel. As much as I like Boxer (even though it doesn’t swim) I think Jaguar and Griffon would have been a better route for us.
“Firstly toxicity, all propelling gasses leave the barrel, therefore none leak back towards the crew operating the weapon, this may seem a tad soft but its a H&S nightmare.”
Quite agree. That was alright in the ‘when you is young you is ‘ard’ days but the realisation is now that the combusted (and part combusted) propellants are not terribly good for you.
Modern boosted missile propellants are sometimes even less good: which is, in part, why soft launch missiles are a good idea.
Some of the early shoulder launched weapons were not nice to be around and if you were ever around a GenI missile launch it was very definitely into the citadel – it was so messy and toxic that it effectively shut down the ship.
“As it was already alluded to, you can change the rate of fire of a chain gun by changing the amount of power going to the drive motor.” Or by using stepper motors to provide a precise incrementation of drive speed.
It has been a bit of a shock the the defence sector as militaries around the world start to catch up with modern H&S standards. Quite right in reference to the “ard” lads, gone are the days of returning from a battle run on the ranges with a bright red face (toxicity poisoning) black hands (cordite burns) def in one ear (blast) numb legs (vibration) and gut rot (range food).
It doesn’t take a lot of imagination to see how that sort of thing effects operational effectiveness.
Interesting article, thank you.
Did I read that correctly, that the operational range of the Mk44 is shorter against ground targets than the Oerlinkon (10 km to 4 km)? That seems quite significant, even if it is more accurate at that range.
It’d be interesting to know what future options there may be, althoguh the absence of them in the article suggests the Navy has no published replacement plan at the moment. I would imagine an upgunning to the Bofors 40 mm might be on the cards, if it’s already to be found on the T31? Or even the CTA40, although I’ve heard that the ammunition for that is prohibitively expensive.
But it’s better ammo isn’t it, and instead of lots of rounds on target you could do the job with far less better rounds,
Yes, it certainly is supposed to be better- although not sure how much better than a 40 mm Bofors equivalent.
From UK Land Power: “It is becoming increasingly obvious that the ammunition costs of CTAS 40×255 mm cannons are all but unaffordable. A HE airburst round costs £250. An APFSDS round close to £1,000. In contrast, a 30×173 mm HE round costs less than $50 and an APFSDS round less than $150.” Just to be clear, the 30 x 173 is the Mk44 Bushmaster round. I think he might be being a tad disingenuous by comparing a 40 mm CTAS HE airburst round to a 30 mm Mk44 HE round (he doesn’t make it clear whether the 30 mm round has airburst functionality), but the cost differences are quite marked.
I don’t know how much of an issue it really is, but I understand Nic Drummond to have fairly good information.
For the record I like the CT40, and I think that commonality across as many platforms would drive costs such as the ammunition down dramatically, but unfortunately history shows that the MOD doesn’t always consider these things in quite the same way…
Even if the RN fitted ct40 weapons to all its ships, the number will still be tiny compared to the 500-odd that the army has agreed to purchase, so I would not imagine a RN purchase would drastically reduce ammo cost.
With this being a uk-French collaboration, does anybody know where the ammo is made?
Not vast quantities, admittedly- if they replaced all the 30 mm mounts then it’d be 41, for all the combat ships including the OPVs but leaving out the mine hunters (according to the table above). That’s taking into account the hulls in future service, bearing in mind the T31 replacements of the T23 GPs will have Bofors 40 mm instead. But I’d imagine they’d carry quite a lot more of the ammunition than an Ajax for each one?
Even then, you make a good point- “dramatic” reduction was maybe a bit too strong a statement from me..!
I do not know how much cta40 ammo the Ajax will carry, but nexter have offered an unmanned turret for the boxer that carries 170 rounds. In comparison the cta40 gun being installed in the French navy’s new OPV has 140 rounds ready to fire.
That’s interesting, I’d have thought they’d have carried more, even on an OPV.
Maybe that’s in the hopper on the turret mount, with more in the magazine on the OPV? I understand that some of these lighter mounts are deliberately not deck penetrating, so that they’re easier and cheaper to fit, but at a cost of access to more ready ammunition in a magazine under the deck.
Wiki says that the CT40 Ammunition will be Manufactured at BAE’s ROF Glascoed Factory.
I think the article is talking about max range the projectile will fly, not the effective range, so 10km is about right for a 30mm round.
Things get complicated when it comes to weapon ranges, max range can mean totally different things. For example, max effective range is different from max slant range and different from max templated range, it also differs wildly between natures. You also have to take into account the target, are you firing at a single helicopter or an entire trench system.
Fair points, thanks for that. It would be too much to hope for that everyone would find a way for an apples to apples comparison…!
Perhaps any discussion of the 30mm mount should include the addition of the Martlet missile .
I believe the mount a 12.7 or 50 cal can be fitted as well would be an interesting mix to cover close in, out to 4k with 30mm 3p munitions And martlet out to 8km.
it suck how we don’t use a dual feed, we could have two different types of ammo ready to fire!! Or have more rounds before refil. Everyone always talks about the phalanx rate of fire but that means ammonia will last far less and will need reloaded. I like the look of the 40mm Bofors, with smart rounds ect,
Would there be any size/weight issues eventually replacing all of the DS-30’s with the 40mm system going on the T31?
Thought the direction of travel was commonality being king but we’re going to end up with 20mm, 30mm, 40mm, 57mm, 114mm and 127mm guns across the fleet.
Good point. After getting to the 30mm calibre , they end up with 2 different models and now 40mm is back as well. The RAF had the same multiplicity of light calibres
Repeat of the WW2 medium gun issue with a 4 in, a 4.5 in , two different 4.7 in ( 120mm) and a 5.25 in. The USN just had the 5 in, which remains the main medium caliber to this day.
The answer to every new issue seems to be a different calibre
I’d have like to have seen the RN rationalize down to 40mm, 76mm and 127mm for all roles.
Even though they’ve gone for the 57mm i’d still hope to see combinations of that and the 40mm bofors replace Phalanx and the 30mm mounts in time.
The USN did use a lot of 5″/38s but it was never that simple. By the end of the war, they were producing 5″/54s with completely different ammunition. They also used 5″/25s which used fixed vice semi-fixed ammunition. There were still 5″/51s in service and 4″/50s. There were also many 3″/50s and a few 3″/23s.
Currently the USN is down to the 5″ Mk45, 57mm Mk110, 30mm, 25mm, and 20mm Phalanx
30mm is lovely, having maintained 40mm Bofor, 20mm Oerlikon and Gambo and the Twin 30mm. But, it is better with a pannier full of LMM on the side.
Genuine question but are these weapons now obsolete with the introduction of the 40mm CIWS?
With the 40mm able to defend against incoming missiles from my layman perspective it seems like a more versatile choice. There does not seem to be a large difference in space and weight requirements. Moving forward would it make sense to phase these out?
We have them and that makes them cheap.
Isnt CIWS a much much higher max rate of fire?
https://www.navylookout.com/last-ditch-defence-the-phalanx-close-in-weapon-system-in-focus/
They are now at 4500 rpm but of course can still be used at low angle for small surface craft
I am referring to the 40mm that will be introduced on the type 31. https://www.baesystems.com/en/product/40mk4-naval-gun
This gun has 300rpm but programmable airburst ammunition.
X- Like I originally said would it not make sense moving forward (new build vessels) to have the 40mm system? I am not suggesting replacing all at once. Just phasing the 30mm mounts out to eventually achieve commonality with one system. It is being introduced anyway. Perhaps there is an operational reason not too.
Yes. My point is MoD recycles an awful lot. As has been highlighted above we will soon have a shocking mix of guns with a couple of mismatches. It is a mess.
As I said a couple of threads back I would like to see T45 have 4 of the Bofors mounts. One at A to replace the Mk8, two to replace the Phalanx, and one, if it could be managed on the hangar roof. I am big fan of the system.
Your idea for type 45 makes perfect sense to me. When faced with a barrage of AShMs a strong last line of defence seems like a sensible investment. Relying on your outer layers to work perfectly every time seems optimistic.
When I look back for a historical analogy I keep thinking of kamikaze. Basically guided anti ship missiles. Then as now there was a multi layered defence. The inner layer defence was as many small (40mm ish) weapons as possible. Make them fly through a wall of projectiles and shrapnel. Technology has of course moved on but just as missiles have progressed so have fire control and ammunition types. The 40mm system seems like a good choice in combination with decoys. That is my thinking anyway.
Yes. You have your various flavours Asters, then SeaCeptors (quad packed, both variants), and then the guns plus something that gets often forgot here EW. Two 45’s at the centre of the carrier group would be the ultimate goal keepers…….
I’d like to see that too. 1x 57mm in place of the main-gun and 3x 40mm or 2 of each? Either way it’d provide great all-round defensive coverage.
Would be logical to see a gradual phasing out of the 20 and 30mm mounts to standardize with the 40 and 57mm systems for surface/air defence and 127mm for NGS.
I don’t know whether we would gain much putting a 57mm at A. Even though 57mm is much larger than 40mm it is still small small. You can end up thinking we need every ‘size’ of gun from 20mm up. Note the Italians and French saw the 76mm radar laid gun was the best option which is even bigger than 57mm. So perhaps a 76mm at A just for the extra oomph? If T45 were more ‘general purpose’ I would stick a 5in at A. But with only 6 of them they are staying in the middle of any group. It is all very complicated. 🙂
The 76mm can also utilise options like Volcano which gives you 40km range. Expensive – yes, but compared to a missile – no. Volcano is an option on both 76mm Compact (upgrade kit may be required) & Super Rapid. Normal Volcano rounds (76mm is new), include unguided, GPS guided, GPS+ RF guided & GPS + laser designated.
I seem to recollect that the KCB 30mm round was painfully expensive compared to the chain gun round. I would assume that the Mk 1 will only be around until ammunition stocks are used up.
The 30mm Bushmaster on the DS30M can very easily be upgraded to 40mm by replacement of a few parts. That’s according to both manufacturers (gun and mount).
Of course, being larger, fewer rounds would be carried on the mount.
As hinted in other posts, programmable Bushmaster 30mm ammunition, comparable to the Bofors 3P, is being developed in the US.
Realistically that needs twin switchable feeds.
One for dumb ammunition for swarms and the programmable for anti air and ant missile use.
Oh, that will be added later at roughly the original full cost when done as an ‘urgent requirement’. One hit from an Ansar Allah missile while in Red Sea transit will concentrate minds
Agreed. Having lived in Yemen for 5 years [until 2008] I know how easy it would be to mount an attack on ships transiting the Bab el Mandeb. There is a usually deserted road which, handily, runs right down to the coast in the correct location.
Problem is that the 30mm round lacks space. Fine for knocking out UAV’s & the like, but a bit limited otherwise. Normal airburst 30mm already exists from the likes of Rhinemetal. The 40x180mm though would likely be a better starting point than 30×173. You would end up spending more money to develop something half as good, as against installing the upgrade kit to 40×180 & leverage the work done on BAE Bofors 40mm P3 to give you a running start. Reinventing the wheel just because you can, rarely pays off.
Also the 40×180 uses a case more like a pistol cartridge (no sholder). It looks more like a 9mm or .22 LR rimfire round than say a 7.62mm (shape wise). So space wise, it’s not as bad as you would think. Thats why so few parts need changing. ie the projectile is larger, but the case diameter not so much (may even be the same?). For the totaly confused – most centerfire rifle & fixed artillary ammo has a fat case (maximum powder) & is necked down to a smaller projectile at the pointy end (eg 7.62mm, 5.56mm etc). Most hand gun (pistol/revolver) ammo & some dual use ammo, has a case that is roughly the same diameter as the projectile (ie no sholder as no necking down). eg 9mm, .357, .38, .45, .22 rimfire etc.
Naturally I welcome the news that HMS Queen Elizabeth will receive her 30mm outfit before her first operational deployment later this year.
However, we should remember that these weapons will have no real capability to defend the ship against incoming anti-ship missiles – of either the super or new hypersonic type. Furthermore, because this ship mounts only 3×Phalanx CIWS systems (and no AAW missile system like most/all of her contemporarys do) QE is effectivly undefended from certain attack vectors – even if you consider this ageing 1970’s era CIWS system is still viable in the first place. Yes the theory is that escorts are always available but the contemporary hypersonic threat implies that the need to develop laser based defensive systems, and mount them widely in the fleet, may now be pressing.
The above (excellent) article reminds us that we sent our warships into mortal combat during 1982 with hopelessly outdated gunnery AAW defences – and payed a heavy price for that grave policy error arguably. One fears we may be making exactly the same mistake again today.
For the want of a nail …
Your comment is another reason why I would like to see the 30mm replaced by the new 40mm weapons. This would instantly increase CIWSs from 3 to 7 on the carriers.
MSI should be looking at ways to create CIWS instead of their traditional mounts.
You suggest that every ship in every navy was fully equipped with every up to date weapon.
They were not. We just happened to be the one doing the fighting.
Ok, I give in. Other than getting people to join up, can anyone provide a specific example of a navy news site improving productivity of the UK workforce?
“Firing horizontally it can reach 10km”
This might lead people in error, it means firing at 45º or so to achieve max range.
In short the anti aircraft range stated is probably firing more horizontally than that one.
The chaingun range measurements are probably not like for like regarding the 30mm.
MK44 Bushmaster II 30mm, 30 x 173 cartridge ~5,190 mm3, 200 rpm, but would think as air cooled barrel max burst would be in the order of ~ 10 sec ?, before forced to stop due overheating, ~30 rounds. Understand the USN MK46 gun weapon system uses a water cooled barrel MK44 Bushmaster II 30mm
Did see mention effective range of 2 km, might be longer, for ref the 35 Millenium with its larger cartridge, 35 x 228 ~7,980 mm3, 1,000 rpm, keep out range quoted as guided range of 3.5 km, max effective range for sea skimming missiles 1.5 km.
Excellent article, many thanks.
Excellent article. No surface combatant, from OPV to CVN should go to see without at least 1 CIWS though, whether Phalanx, SeaRAM, or RAM. Just my thoughts.
Interest articles I revisit this for ages, re-reading all over the whole again and still enjoy.
I think we should upgrade DS30mk2 to DS40mk3 either BOFOR 40MM P3 or CTS40MM with LMM / Starstreak MK2/3 on both side of turret as spawn drone POV (Or other type) or drone USV, even can defence cruise missiles.
Learn lesson from Ukraine and Yemen, Iran.
Patrol ship or unmanned boat etc should have 1 or 2 per ship
4 each corners of all of the ship will cover full 360ø as standard plus 2 laser ciws
4-8 for QoE carrier plus 2-4 laser ciws.
Boxer and antiair platform ilauncher switch canister to turret put on base or front line (and Ajax) should have 40mm cannon so can shot airburst ammo on POV drone which would usefully learn from Ukraine war.
It is will cheap if multiplatform as common ammo (airburst fuse frag for drone / aircraft and HE airburst fuse for soft armour, AP-Impact for bunker and old tank or light armour)
Wish fighter aircraft can fit this cannon but don’t think cos too big for this weapon also speed will too fast in future.