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Replacing the Type 12 Leander

uk 75

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The Leander frigate is fondly remembered as perhaps the most successful postwar class of Royal Navy frigate. The Dutch also used the design.
Replacing the Leander proved quite difficult.
The Type 22 was a very different ship, much more specialised and expensive. In fact the Type 23 was closer to the Leander in appearance if not cost.
The interim replacement for Leanders in the building programme was the Type 21 frigate which was closer to the Type 81 Tribals in scope.
The US Navy had introduced its Knox class as a similar ship. The Knox class served longer than the Leanders, though they were introduced later.
Could the RN have introduced a replacement for its Leanders more effectively than it did and perhaps avoided the costly conversions
 

uk 75

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I have read through this interesting what-if and have a number of thoughts inspired by it.

Platforms: The Type 21s always struck me as a straightforward replacement for the Tribal class, fast light frigates that could be used around the world. It is no accident that they were a major class sent to the South Atlantic. The original replacement in the line up for the Type 12 was supposed to be the Type 82. When this got too big and expensive, substitute platforms were looked at. The AA frigate morphs into the Type 42 destroyer and the ASW frigate morphs into the Type 22 frigate, though both are roughly the same size.
Could another general purpose frigate have replaced the Type 12 in production in the 70s, and instead of the last few ships?

Weapons: Before answering the question of whether a new platform could have been started in the late 60s, I want to ask some questions about the weapons:

CF299/Seadart This had grown too large for a frigate and the Type 82 Bristol as a one off trials platform was probably the safest route.

Seawolf This system proved much more complicated to develop than had been envisaged. With the benefit of hindsight only, the Seacat 2 fitted to existing launchers would have been a sensible insurance policy (only the basic BPDMS system was available in the late 60s as an alternate, with Crotale and Roland having similar risks to Seawolf without the capability. Even a VLS Seawolf system would have been delayed until the late 70s. If this could have been made to fit the space taken by Seacat and its radar/directors so much the better.

Ikara This system lost its platform with the cancellation of the Type 82s. Frankly I have always seen it is a dead end. The Type 22s did not use it, and the converted Leanders had only a shortish lifespan. Seakings arriving in the late 60s should have been adopted using the Canadian beartrap and related hangars. This would also have allowed the scrapping of the Tiger and Blake.

Exocet The requirement for an SSM emerges in 1966 with the end of the carriers. The Exocet and its bulky boxes seems to have been the only choice until Harpoon.

To be continued
 

zen

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"Could the RN have introduced a replacement for its Leanders more effectively than it did and perhaps avoided the costly conversions?"

Yes of course it could, but it does require a number of changes.

However you don't seem to be asking questions so much as stating things.

Type 21 was indeed the spiritual successor to the Type 19, and Type 81 before that. But it was if anything a bit of a dead end thanks to RN imposing severe changes from the original commercial Frigate design.

Several things transform the situation.
1. The move to CoGaG, as GTs weighed less, needed less manpower, and allowed for shorter refit/maintenance time in dock.

2. Increasing computing power allowed a move to digital automation of the AIO.
Ironically this should have stuck with ADAWS but they went for the supposedly simpler and cheaper CAAIS which was a failure.

3. The medium to light helicopter such as Lynx could deliver anti-surface weaponry, small teams, or anti-submarine weaponry at less cost resources and complexity than separate missile systems.

Strictly a ship between 4,500tons to 5,000tons could deliver.
 

uk 75

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Zen You are right. I meant to go back and correct my assertions into questions, but got timed out on the Library computer.
Essentially if you whittle down the armament choices perhaps the Leanders could have been more easily converted:
simplify the eventual SSM fit or move them?
drop Ikara and replace with Seaking? or later on Lynx instead of Wasp.
Replace Seacat with an interim point defence missile on the existing launchers?
That would give you a single type fit which could serve into the 80s while a new GP frigate is introduced?
The new GP frigate would like the T23 look much like a Leander in layout?
Gun forward
SSM midships Harpoon
 
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uk 75

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sorry phone cut me off

single ended Seawolf
helo aft
Type 22 seems to me too big and expensive to be bought in numbers. Type 24 looked closer to my ideas?
 
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zen

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If Sea Wolf remained VLS as was intended. Then the double ender is only the Type 810 sets.
If Sea Wolf had been System C, then not only would the French remain onboard, but it's potential for the Army would drive up numbers and lower unit cost.
If instead we'd driven ahead with SAM.72, we'd dump Sea Dart and a VLS MSAM system would result.

If PT.428 proceeded earlier then the life of Sea Cat systems was numbered and something like the Type 21 would have a longer valid life.
I'll dive that a little as that was offered in two forms and two missiles. A simple Sea Cat like system (manual target tracking like Rapier) and a much more automated system (equal to Mauler). A short range unitary missile (5nm), and a longer ranged boosted missile (possibly 10-15nm).
Logic suggests the guidance is relevant to faster missiles, though range is dependent on the radars.

So pragmatically at the period the Type 22 was sound, give it VLS Sea Wolf, or System C or SAM.72 and it's utility increases. But of these SAM.72 means a common hull AAW and ASW ship is possible. No need for Type 42.

Strange failing is the lack of maritime Avon as a GT.....an earlier Spey and cheaper than Olympus.

Guns and the stripping off of gun systems for the 20mm and 40mm was a wasted opportunity.

Don't fret, I'm using my smartphone as getting time on the PC is hard work inofitself
 

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On Ikara being a dead end, if you have space for Limbo, you have space for Ikara, if you have space for Exocet or Harpoon, you have space for Super Ikara. If you have two escorts or an escort and a helo with either dunking sonar or sonar buoys you have triangulation for Ikara at long range. The only reason Ikara didn't stay in RN service longer is the installation designed for the Type 82 (and used on the Leanders) was a volume hog and harpoon was considered more important for the Type 23 than Super Ikara.

A little stretch and Super Ikara could have easily been installed on Type 22 and Type 23, Batch III Type 42 could have probably fitted it between the Sea Dart and Bridge structure.

Something I have wondered about ref the Broad Beam Leanders, is whether a Oto Melara ompact or Super Rapid could have been fitted further forward on the bow than the Dutch did with their modernisation of the Leander, thus freeing the space previously occupied by the 4.5" for something else, i.e. a Mk 22 GMLS for SM-1. Replace Limbo with Ikara with a cut out in one corner of the stern, meaning lynx can still be accommodated.
 

uk 75

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Cpnvertong Leanders and Rothesays falls happily into this thread. I am grateful to all for contribuing info and ideas
My own preference would have been Seakings with Canadian style hangars and beartrap.
The 4.5' turret seems to have performed well enough in its various roles. As Leanders/Rothesays would give way to T22s (pref all in Batch 3 version) and T42s in the 80s I would be inclined to save money and keep the old turret.
From 1981 a Phalanx fit should replave Seacat
I would order Harpoon sooner so that it can replace Exocet on T21 and T22 from 1983.
With Seakings on all T12s and then T22s Lynx would only go on the T21 and T42.
 

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The 4.5" turret was not particularly popular in the Dutch navy. The Van Speijk-class (modified Leanders) had their 4.5" turrets replaced by Italian 76 mm turrets, while, in about the same period, the missile-frigates Tromp and De Ruyter were fitted with older, refurbished 120 mm turrets. Taken from the old destroyer Gelderland, built to a Bofors design and extremely well-liked by the crews that used them. The 4.5" turrets were scrapped. At some time, British 4.5" guns were considered for Tromp and De Ruyter, but not selected.
 
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uk 75

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I think if you look at the armament of the Dutch Kortenaer (apls on spelling) which had a 76mm gun replaced by a Goalkeeper it made great sense to fit this weapon and Harpoon to its Van Spejik class. Similarly reusing the turrets for Tromp and De Ruyter made sense I think the Italians did the same thing with their destroyers.
But none of these weapons were standard in the RN at the time of my Type 12 refurbs.
Replacing the UK 4.5" in the 80s with a foreign gun was unlikely.
 

zen

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Yet the Swedish 4.7/120mm very nearly did get chosen for the RN.
And the Italian 76mm did serve on the Peacocks if I recall correctly.

The Dutch nearly bought into both Sea Dart and Sea Wolf....and Ikara....
And to top it off nearly went for the French 100mm gun.

So in AH terms, there was quite some scope here and with it potential alternative successors to the Leander class.

Consider the 120mm. A twin turret was in offing during the Cruiser Destroyer and Super Daring process.
It could have been that the Vickers mkN mount might have been with a single 120mm instead of the 4" sold to Chile.
Potentially then the 4.7"/120mm could progressively muscle out the 4.5"....
 

uk 75

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Vickers supplied the same gun to the Army as well. It is only now that the US 5" has been chosen to replace it.
The 76mm was the original choice for the Type 23. Falklands gunnery experience upped it to the 4.5" gun.
Sticking to the Type 12s (Leander and Rothesay) armaments. The West Germans used the French gun on their own design corvettes and destroyers before going to the 76mm. The Italians sold their 127mm to Canada and Japan.
In real life the Leanders were forced to stand in for Type 22s which should have been built in greater quantities. In my alt Royal Navy they serve to replace the 2d rate frigates (Tribals, Salisbury, Leopard etc).
 

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Don't forget that Bofors made two different 120 mm naval guns post-WW2: an L/50 gun in a twin mounting introduced in 1950, fitted to Swedish and Dutch ships (I recall reading an assessment - I think by the RN - which concluded that it was a better mounting than the 4.5 inch Mk 6); and then there was an L/46 gun in a single mounting, introduced in 1967 (i.e. a direct rival for the 4.5 inch Mk 8). This L/46 mount weighed about the same as the Mk 8, but fired at 80 rpm rather than 20 - some serious AA potential.
 
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zen

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It occurs to me that a 4.7 L50 single MkN mounting might be highly complimentary with the Swedish twin mounting. In fact the ideal would be the water cooled high rpm mounting bring designed for the Cruiser Destroyer.
And perhaps the next generation would increase to L62 or L70....the Swedes did develop a 4.7 L70 for fortresses.....
 
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