RN Type 21 weapons fits

[uk 75]

Back in the 70s artwork from Vospers (reproduced here on a popular contemporary UK wargame) showed a Type 21 using very lightweight Seawolf launchers.
Type 21 has not been covered much here. It started life with a very basic weapons fit, and got Exocet added without losing its main gun unlike the larger Leanders.
It was supposed to get Seawolf. Obviously there was no room for the clumsy launcher used on T22. Or did it originally go where the Exocets went.
Few drawings exist.
Obviously as a GP frigate there was no Ikara variant (pretty certain of that).
Before Exocet was chosen in 1970 were SS12 launchers to be fitted (the Wasp helo carried them but a launcher features on some RN drawings of unbuilt ships)

 

[Pirate Pete]

I recall MANY years ago an article in the Portsmouth News (local newspaper) which included a sketch (illustration) of a 'proposed' stretched Type 21. I think the beam was to be increased by approx 2 feet (circa 60cms) and the illustration include both Exocet and lightweight Seawolf. I used to have the article but it got lost years ago in a house move, also it was before scanners were readily available.

Slight subject tangent (using the term slight VERY generously), there was another Portsmouth News article which hinted at "Invincible 6-times over". I think it was talking of a total of five vessels for the British Royal Navy, and one for the Shah of Iran's Navy, which I believe at that time also included 'plans' for six modified Spruance class DDG's (later the four USN Kidd class vessels), 'S' or 'Standard' class frigates (of the type built for the Royal Netherlands Navy), plus submarines, which I think were of Howaldtswerke-Deutsche Werft (HDW) design Type 209?

 

[Volkodav]

I recall MANY years ago an article in the Portsmouth News (local newspaper) which included a sketch (illustration) of a 'proposed' stretched Type 21. I think the beam was to be increased by approx 2 feet (circa 60cms) and the illustration include both Exocet and lightweight Seawolf. I used to have the article but it got lost years ago in a house move, also it was before scanners were readily available.

Slight subject tangent (using the term slight VERY generously), there was another Portsmouth News article which hinted at "Invincible 6-times over". I think it was talking of a total of five vessels for the British Royal Navy, and one for the Shah of Iran's Navy, which I believe at that time also included 'plans' for six modified Spruance class DDG's (later the four USN Kidd class vessels), 'S' or 'Standard' class frigates (of the type built for the Royal Netherlands Navy), plus submarines, which I think were of Howaldtswerke-Deutsche Werft (HDW) design Type 209?

The Shah wanted three Invincibles and Sea Harrier, the S Type derivative was to have had a 5" and a Mk 13 GMLS forward of the bridge (I have a sketch somewhere but cant remember where I found it and definitely cannot verify it as the actual config offered). The six Invincibles were what was initially proposed for the RN, I have a feeling this is stated in Browns Rebuilding the Royal Navy.

I have seen a sketch of the "broad beam" Amazon, in an old 1970s edition of an Airfix Model magazine of all places, infact it may even have been a photo of a concept model from MOD or one of the ship yards. It had the 4.5" forward and four twin Seawolf Launchers (on each side of the deck house forward of the bridge and one each side of the hangar) as per CJGibsons post here back in 2007. https://www.secretprojects.co.uk/attachments/seawolf_twin-jpg.22313/

 

[TomS]

Surprisingly little published about the Type 21 evolution. DK Brown skips over it almost entirely and Friedman has only a short section. From Friedman, the plan was for the ship to have Seawolf above the hangar but it was not ready in time, so Seacat was fitted in the interim. Fitting Seawolf was expected to require removing the gun fire control radar as a weight compensation, relying on the SW's Type 968 (the Type 910 would be in the wrong location to double as a gun fire control radar.)

 

[Hood]

I think the fact is was privately designed rather than being a DNC product probably meant that Brown and Friedman had less archival history on the actual ship so they tended to focus on the cheap frigate saga and the Australian high-speed concepts that brought about Type 21 from what they could glean from the national archive collections.

Type 21 did a good job I think for what it was designed to do. Yes it was too small and lacked any growth capacity but for patrolling and showing the flag it didn't need fancy systems and arguably made a good replacement for the Type 81 in the overseas role. That it required structural repairs after the Falklands was not really its fault, those were punishing conditions for any ship and although it lacked modern air defence weapons, it was no worse than the Leanders in that respect. It could at least carry a 4.5in gun, Sea Cat and Exocet at the same time, something Leander could not do.
They filled the numbers gap, they were much akin to the Type 31 today, lower end ships to boost numbers. The RN would certainly never have received an extra eight Type 22s in their stead.

If a lightweight Sea Wolf had been made available sooner it might well have changed these ships. At least one of them gained Phalanx in Pakistani service.

 

[JFC Fuller]

From Friedman, the plan was for the ship to have Seawolf above the hangar but it was not ready in time, so Seacat was fitted in the interim. Fitting Seawolf was expected to require removing the gun fire control radar as a weight compensation, relying on the SW's Type 968 (the Type 910 would be in the wrong location to double as a gun fire control radar.)

I wonder whether this got caught up in the size, weight and complexity growth of the Sea Wolf system. The earliest ship designs with PX.430 show a single launcher aft with one director also aft and director another forward, the aft director looks to have more than sufficient coverage to match that of the launcher suggesting the forward director was intended primarily for gunfire control. The launchers and directors look significantly smaller. In the Type 42 and 82 the Type 909 was used for control of the 4.5". That is to say, it is possible that the Type 21 was designed to allow direct replacement of its Seacat launcher, director and gunfire control system with the PX.430 as originally intended, and that replacement became impossible later due to changes/weight growth in the Sea Wolf system. Certainly the the ealirest PX.430 draft requirements called for a system that could use Seacat system components.

 

[Hood]

I wonder whether this got caught up in the size, weight and complexity growth of the Sea Wolf system. The earliest ship designs with PX.430 show a single launcher aft with one director also aft and director another forward, the aft director looks to have more than sufficient coverage to match that of the launcher suggesting the forward director was intended primarily for gunfire control. The launchers and directors look significantly smaller. In the Type 42 and 82 the Type 909 was used for control of the 4.5". That is to say, it is possible that the Type 21 was designed to allow direct replacement of its Seacat launcher, director and gunfire control system with the PX.430 as originally intended, and that replacement became impossible later due to changes/weight growth in the Sea Wolf system. Certainly the the ealirest PX.430 draft requirements called for a system that could use Seacat system components.

Don't forget those VLS tubes on the Patrol Ship Study 919. Its a shame PX.430 never followed the VLS route, it could have made upgrading even more simpler.

 

[Volkodav]

The Australian version with US systems mentioned by Brown would have been an interesting beast, does anyone have any further information on it? If memory serves it was meant to be larger and faster than the RN Type 21 but little else was discussed, I would assume a Mk 45 5" in place of the Mk8 4.5" and Sea Sparrow in place of Seacat, as well as a US sensor fit (with some Dutch offerings thrown in as well) and although the RAN looked at fitting the Mk13 to pretty much everything at some point, I can't see it being an option on even a stretched Amazon.

 

[Grey Havoc]

Don't forget those VLS tubes on the Patrol Ship Study 919. Its a shame PX.430 never followed the VLS route, it could have made upgrading even more simpler.

Though US naval VLS systems at least were still pretty immature for much of the 1980s, not to mention drawbacks such as reloading at sea (or lack there of).

 

[M. A. Rozon]

As to Type 21's growth margin for upgrades such as Seawolf and towed array, if memory serves, various commentators, including Brown and Friedman, have remarked that the Type 21 could not accept the weight growth for these systems without increasing draft to the point of putting the damage control deck of the ship at or below the waterline. The final design of the stern also made it impossible to accept a towed array without a great deal of change. This inability to accept the towed array cut short the life expectancy of the class within the RN.

 

[TomS]

The Australian version with US systems mentioned by Brown would have been an interesting beast, does anyone have any further information on it? If memory serves it was meant to be larger and faster than the RN Type 21 but little else was discussed, I would assume a Mk 45 5" in place of the Mk8 4.5" and Sea Sparrow in place of Seacat, as well as a US sensor fit (with some Dutch offerings thrown in as well) and although the RAN looked at fitting the Mk13 to pretty much everything at some point, I can't see it being an option on even a stretched Amazon.

Friedman has some basic specs. It was indeed faster and slightly larger. The primary radar was AWS-1, but the hull sonar was American (EDO 610). It was indeed Sea Sparrow, with 24 missiles (versus 18 Seawolf in the British version). The RAN version also had more austere EW provisions. The RN version was still considering Limbo or Terne ASW mortars, while the RAN version was just using lightweight torpedoes.

 

[Rickshaw]

The Australian version with US systems mentioned by Brown would have been an interesting beast, does anyone have any further information on it? If memory serves it was meant to be larger and faster than the RN Type 21 but little else was discussed, I would assume a Mk 45 5" in place of the Mk8 4.5" and Sea Sparrow in place of Seacat, as well as a US sensor fit (with some Dutch offerings thrown in as well) and although the RAN looked at fitting the Mk13 to pretty much everything at some point, I can't see it being an option on even a stretched Amazon.

Friedman has some basic specs. It was indeed faster and slightly larger. The primary radar was AWS-1, but the hull sonar was American (EDO 610). It was indeed Sea Sparrow, with 24 missiles (versus 18 Seawolf in the British version). The RAN version also had more austere EW provisions. The RN version was still considering Limbo or Terne ASW mortars, while the RAN version was just using lightweight torpedoes.

"Terne"? Wasn't that a Norwegian system? I didn't think either the RN or the RAN would have used such a system.

 

[Hood]

"Terne"? Wasn't that a Norwegian system? I didn't think either the RN or the RAN would have used such a system.

Yes it was Norwegian. Not exactly a compact system either and I fail to see where it could easily have been fitted on the Type 21 or the Type 42 (probably sacrificng the Exocet positions in T21 and maybe between the 4.5in and Sea Dart on the original length T42 design?)
The Bofors system was also looked at for the RN at least. I don't think there were any other modern Western A/S mortar options at that time.

Frustratingly my university library used to have a Terne brochure but its got culled and sent for pulping...

 

[TomS]

"Terne"? Wasn't that a Norwegian system? I didn't think either the RN or the RAN would have used such a system.

It's listed as an alternative to Limbo in the 1967 studies. A few years earlier, the USN had placed it on a couple of DEs and I think there was some consideration of making it a NATO standard weapon. But realistically, no, it wasn't going to happen. And the RAN version never considered anything but lightweight torpedoes.

 

[TomS]

"Terne"? Wasn't that a Norwegian system? I didn't think either the RN or the RAN would have used such a system.

The Bofors system was also looked at for the RN at least. I don't think there were any other modern Western A/S mortar options at that time.

Also the Italian Menon, a semi-automatic launcher firing a seven-round pattern, sort of similar in concept to Weapon Alfa. And there was the French four-tube automatic 305mm mortar on the Commandant Riviere class. Those doubled as bombardment weapons, so were perhaps ideally suited for colonial policing duties.

Edit: worth mentioning that these studies were well before any line drawings were done, so ship layout could well have been different than the Type 21 as built. If Limbo had been used, it surely would have been aft of the helo deck, Terne would likely have been forward, etc.

As I read more, it's really a pity they couldn't have gone up one "size" in the Vosper line. The Brazilian Niterois are about 10% larger but seem much more flexible. Room for both A/S mortars and a second lightweight Seacat (so probably weight for Seawolf) as well as a second gun or Ikara and VDS (or likely a towed array for the RN).

 

[Volkodav]

"Terne"? Wasn't that a Norwegian system? I didn't think either the RN or the RAN would have used such a system.

The Bofors system was also looked at for the RN at least. I don't think there were any other modern Western A/S mortar options at that time.

Also the Italian Menon, a semi-automatic launcher firing a seven-round pattern, sort of similar in concept to Weapon Alfa. And there was the French four-tube automatic 305mm mortar on the Commandant Riviere class. Those doubled as bombardment weapons, so were perhaps ideally suited for colonial policing duties.

Edit: worth mentioning that these studies were well before any line drawings were done, so ship layout could well have been different than the Type 21 as built. If Limbo had been used, it surely would have been aft of the helo deck, Terne would likely have been forward, etc.

As I read more, it's really a pity they couldn't have gone up one "size" in the Vosper line. The Brazilian Niterois are about 10% larger but seem much more flexible. Room for both A/S mortars and a second lightweight Seacat (so probably weight for Seawolf) as well as a second gun or Ikara and VDS (or likely a towed array for the RN).

If it had Limbo it could ship the RAN config Ikara, the system fitted to the RAN River Class (Type 12) DEs was configured to replace the Limbo and its magazine.

 

[Volkodav]

I recall MANY years ago an article in the Portsmouth News (local newspaper) which included a sketch (illustration) of a 'proposed' stretched Type 21. I think the beam was to be increased by approx 2 feet (circa 60cms) and the illustration include both Exocet and lightweight Seawolf. I used to have the article but it got lost years ago in a house move, also it was before scanners were readily available.

Slight subject tangent (using the term slight VERY generously), there was another Portsmouth News article which hinted at "Invincible 6-times over". I think it was talking of a total of five vessels for the British Royal Navy, and one for the Shah of Iran's Navy, which I believe at that time also included 'plans' for six modified Spruance class DDG's (later the four USN Kidd class vessels), 'S' or 'Standard' class frigates (of the type built for the Royal Netherlands Navy), plus submarines, which I think were of Howaldtswerke-Deutsche Werft (HDW) design Type 209?

The Shah wanted three Invincibles and Sea Harrier, the S Type derivative was to have had a 5" and a Mk 13 GMLS forward of the bridge (I have a sketch somewhere but cant remember where I found it and definitely cannot verify it as the actual config offered). The six Invincibles were what was initially proposed for the RN, I have a feeling this is stated in Browns Rebuilding the Royal Navy.

I have seen a sketch of the "broad beam" Amazon, in an old 1970s edition of an Airfix Model magazine of all places, infact it may even have been a photo of a concept model from MOD or one of the ship yards. It had the 4.5" forward and four twin Seawolf Launchers (on each side of the deck house forward of the bridge and one each side of the hangar) as per CJGibsons post here back in 2007. https://www.secretprojects.co.uk/attachments/seawolf_twin-jpg.22313/

Found it!
https://archive.org/details/Airfix_Magazine_1976_05/page/n5/mode/2up

 

[TomS]

I have seen a sketch of the "broad beam" Amazon, in an old 1970s edition of an Airfix Model magazine of all places, infact it may even have been a photo of a concept model from MOD or one of the ship yards. It had the 4.5" forward and four twin Seawolf Launchers (on each side of the deck house forward of the bridge and one each side of the hangar) as per CJGibsons post here back in 2007. https://www.secretprojects.co.uk/attachments/seawolf_twin-jpg.22313/

Found it!
https://archive.org/details/Airfix_Magazine_1976_05/page/n5/mode/2up

Interesting. You can see the evolution to the Niteroi/Mk10 design here, with the creation of room for SSMs and minor-caliber guns amidships. This one is probably still shorter than the Mk10 though.

 

[JFC Fuller]

Thank you Volkodav, great find! Given our recent experience with online archives I have attached a screenshot of the image and text. Also, here is a link to a post on this forum about the twin rail, light weight, Sea Wolf launcher.

 

[Hood]

I have never come across the Broad-Beam Type 21 before. I wonder if it was simply a marketing concept rather than a genuine export market attempt? By 1976 the Vosper Thornycroft series had moved on some way and why bother when the Mk.10 Niteroi had already opened the way to a larger and more capable design.
I attach an image of the Mk.17 which dates from 1982 to illustrate my point.

I got to thinking about the Type 21 design saga so started to sift through the various designs of the Vosper family tree as well as those proposed for the Type 19 and joint RN/RAN requirements. I added Yarrow's efforts of the time too for comparison.

Vosper 1962 Corvette (offered to RCN, made public 1963) – 177 x ? ft, Olympus-Deltic CODOG for 50kt
Vopser Mk.1 – 440 tons, 177 x 28.5ft, 1x 4in, MTU or Paxman diesels for 20-18kt
Vosper Thornycroft Mk.3 – 580 tons, 202 x 31ft, 1x2 4in, MAN diesels for 22kt
Vosper Thornycroft Mk.5 Saam – 1,100 tons, 310 x 36.3ft, 1x 4.5in & 1x2 35mm & Limbo & 1x5 Sea Killer, Olympus-Paxman CODOG for 39kt
Vosper Thornycroft Mk.7– 1,360 tons, 333 x 38.3ft, 1x 4.5in & 1x2 35mm & 1x Albatros Aspide & 4x Otomat, Olympus-Paxman CODOG for 37.5kt
Vosper Thornycroft Mk.9 – 680 tons, 226 x 31.5ft, 1x 76mm, Bofors A/S mortar, 1x Sea Cat, MTU diesels for 27kt
Type 19 – 1,900 tons, 340 x 35ft, 1x 4.5in, 1x Seacat, 1x helicopter, Olympus-Paxman CODOG for 39kt
DS919 – 1,200 tons, 260 x 33ft, 1x 4.5in, PX.430, 1x helicopter (pad only), Olympus-Tyne COGOG for 28kt
DS920 – 1,200 tons, 270 x 33ft, 1x 4.5in, PX.430, 1x helicopter (pad only), Olympus-Tyne COGOG for 28kt
YARD Y.217 (for RAN) – 2,070 tons, 1x 5in/54, 1 Sea Sparrow, 1x helicopter, Olympus-Tyne COGOG for 35+kt
Type 21 – 3,100 tons, 384 x 41.7ft, 1x 4.5in & 1x Sea Cat & 4x Exocet, 1x helicopter, Olympus-Tyne COGOG for 30kt
‘Broad-Beam’ Type 21 – 1976, 3,100+ tons, 384 x 43.7ft, 1x 4.5in & 4x2 Sea Wolf & 4x Exocet, 1x helicopter, Olympus-Tyne COGOG for 30kt(?)
Vosper Thornycroft Mk.10 Niteroi – 3,200 tons, 424 x 44.2ft, 1-2x 4.5in & Bofors A/S mortar & 2x Sea Cat & 2-4x Exocet & 1x Ikara (10x missiles) [replacing 1x 4.5in], 1x helicopter, Olympus-MTU 16V CODOG for 30kt
Yarrow Rhamat –1,250 tons, 308 x 34.1ft, 1x 4.5in & Limbo & 1x Sea Cat, Olympus-Crossley CODOG for 26kt
Yarrow Makut Rajakumarn –1,650 tons, 320 x 36ft, 2x1 4.5in, 1x Albatros Aspide, Olympus-Crossley CODOG for 26kt

Some things stand out;
The fast corvette offered to Canada in 1962 to replace the Bras D'Or programme seems to have been the genesis of the series, removing the turbine made a nice corvette design that started the ball rolling on the export corvette series.

The Type 19 was certainly of the right ballpark figure for the kind of export frigates then being designed by Yarrow and VT. The high speed was the outlier but certainly speed seems to have become an asset not just for hunting Indonesian 'Osas' but also in terms of attractiveness to export nations - both Libya and Iran saw high speed a price worth paying for. I can't see how the Type 19 would have achieved 39kt on 1,900 tons, that sounds very ambitious, I would think 37kt would be more realistic in practice.

The cost-cutting DS919 and DS920 were relations even compared to export designs, being quite small - though in fairness they were described as patrol vessels.

Its easy to see why the Mk.5 and the slightly later Mk.7 made such an impression on the Admiralty, their avoidance of Mil-Spec requirements enabled them to be piled high with goodies at the expense of other other factors (habitability, ammunition, damage control). Its a wonder that they didn't think 'it must be too good to be true' when they looked at the Mk.5s specs. The Mk.7 actually looks much more of a realistic design overall.

The RN/RAN requirements were incomparable but I think that it had a far more beneficial impact than we give credit for. The Type 19 was heavier but physically not much larger or more capable than the Mk.7. But the RAN's range requirements and armament choices pushed the concept up in terms of size and weight and beyond its Mk.5 competitor. The Type 21 proved to be cramped with little growth but it can be seen that without RAN involvement, that a UK non-commercial solution like the Type 19 would have come out about 1,000 tons lighter and maybe 40ft shorter and maybe as much as 5ft slimmer. Actually it can be seen that the VT export designs were beamier overall, regardless of displacement.

A larger Type 21 would seem unlikely in the circumstances, it was probably as big as was acceptable to the eyes of the late 1960s. The Type 21 had no export success, the Niteroi was the biggest the series got. In terms of exports the sweet spot was around the 1,000-1,400 ton ballpark at that time.

 

[Volkodav]

Australia was very definitely interested in using US systems on what became the Amazon, I think in the Type 19 topic Abraham mentioned they also wanted a more durable hull capable of better using the potential of the RR Olympus. The RAN became quite keen on the US systems following the delivery of the DDGs, as not only were they a generation newer than that on offer from the UK, they also benefited from an extensive ongoing development program supporting the parent navy.

While the Type 21 plans were dropped Australia retained Olympus / Tyne propulsion system for the proposed DDL.

 

[TomS]

Australia was very definitely interested in using US systems on what became the Amazon, I think in the Type 19 topic Abraham mentioned they also wanted a more durable hull capable of better using the potential of the RR Olympus. The RAN became quite keen on the US systems following the delivery of the DDGs, as not only were they a generation newer than that on offer from the UK, they also benefited from an extensive ongoing development program supporting the parent navy.

The British withdrawal from East of Suez (officially 1968 but the writing was on the wall before that) probably also was a major factor, as it became obvious that the RAN was far more likely to fight with the US Navy than the RN in any future global or regional conflict.