Different thought process for Post WW2 British Navy

[Scott Kenny]

Threads like these tend to concentrate on SAMs. However, the RNs post-war record on torpedoes was not exactly stellar. E.g. the Mk 25 Tigerfish is the best known example.

But, the heavyweight ASW torpedoes for surface ships were so bad that they were taken out of service in the early 1960s. The ships that had been completed or refitted with the 21" tubes to fire had them removed and later classes such as the Counties, Leanders & Tribals (which were designed to have 6 of them) weren't completed with them.

Therefore, British surface warships didn't have an ASW torpedo until the late 1970s when they began to be fitted with tubes for 12.75in lightweight torpedoes. Therefore, for about 15 years their main anti-submarine weapon was the Limbo mortar. Yes, the County class had Wessex helicopters carrying ASW torpedoes; yes, many frigates had the Wasp, which came into service in the middle 1960s; yes the Type 82 had Ikara; and yes, 8 Leanders were fitted with Ikara from the early 1970s. But it still looks like a huge gap in the RN's ASW capability from the early 1960s to the late 1970s.

Could anything have been done to avoid that? Use as much hindsight as you like, but bonus points will be avoided if it could have been done without hindsight. E.g. could the 21" heavyweight torpedoes been made to perform adequately?

Well, there's the US weapons, and the Brits did buy some of the US lightweight torpedoes. Specifically, they bought 50 of the 265lb Mk43 torpedoes.

The US Mk34 torpedo was a development of the WW2 Mk24 FIDO, and while it was designed as an aircraft torpedo it could have been pushed over the side via torpedo tubes.

I'm sure buying a few and not-literally-dropping them on the desks of the UK weapons designers and saying "beat this in X time" might produce some motivation to quality torpedoes.

 

[Rule of cool]

Here is a starter for you.

Post-World War II Torpedoes of the United Kingdom/Britain - NavWeaps

www.navweaps.com

A quick look confirms my suspicions that the whole idea was slightly ludicrous.

 

[NOMISYRRUC]

Type 41 Fast Anti-Aircraft (and Aircraft Direction) Frigate

1. OTL Type 12 (broad-beam Leander) hull.
2. OTL Type 12 (Whitby class) machinery.
3. OTL Type 41 armament of two twin 4.5in Mk 6, one STAAG Mk 2, two single Bofors 40mm and single Squid (10 salvoes).
4. OTL Type 41 fire control, but if space and weight permitted a second Mk 6M director would be fitted in place of the CRBFD.
5. OTL Type 41 sonars.
6. OTL Type 61 radars - plus a Type 983 radar in place of the Type 277Q if space and weight permitted. (See note.)
7. OTL Type 61 aircraft direction facilities augmented by a 12-track Comprehensive Display System (CDS) with Direct Plot Transmission (DPT). This CDS was the digital version that IOTL was cancelled in the late 1940s.
8. Fitting CDS & DPT took priority over the Type 983 radar (second priority) and second Mk 6M director (third priority).

9 ships were ordered in the 1945/46 to 1952/53 building programmes. They were laid down 1952-55 and completed 1957-60. One ship was sold to the Indian Navy (which placed direct orders for 2 more) leaving 8 ships to be commissioned into the Royal Navy.

In common with their cousins the Type 12 Whitby class (which ITTL had the broad-beam Leander hull too) they were intended to screen convoys and amphibious task forces. Furthermore, like them (and unlike the OTL Type 41) they were also fast enough to screen carrier task forces, which combined with their aircraft direction capability meant they met the Fleet Aircraft Direction Escort (FADE) requirement.

Therefore, it was decided to build more Type 41s instead of converting 1943 Battle class destroyers into fleet pickets. The first cost was more than the cost of the destroyer conversions, but it was more cost effective because they would have longer service lives. The plan in 1955 was to build 8 ships as a one-for-one substitution of the planned 1943 Battle conversions, but only 4 were built. They were laid down in 1959 at the Royal Dockyards that did the Battle class conversions IOTL and they were commissioned 1962-63. They were designated Type 41 Batch 2 and the differences between them and the Batch 1 ships were:

• The Type 960 radar was replaced by the Type 965P with the AKE-2 aerial. (See Note.)
• The Type 293Q radar was replaced by the Type 993.
• The directors for the 4.5in guns were replaced by 2 digital MRS.5s (with Type 905 radars). IOTL MRS.5 and the Type 905 were victims of the late 1940s defence cuts.
• The STAAG Mk II was replaced by the much improved STAAG Mk III. This used the Bofors 40mm L70 gun and was developed instead of Sea Cat. The improvements over the Mk II included being more reliable and needing less maintenance.
• The UA-8/9/10 ESM system was fitted.
• The Type 667 ECM system was fitted.
• ABCD defence measures which AFAIK the OTL Type 41s and 61s didn't have.

The 8 Batch I ships were refitted to this standard between 1961 and 1968. That was their only major upgrade and they were paid off in the second half of the 1970s. The 4 Batch 2 ships survived long enough to take part in the Falklands War. They might have had mid-life refits between the late 1960s and early 1970s which would have included replacing the CDS with the second-generation ADAWS (with FM1600 computers), a new air surveillance radar and replacing STAAG Mk III with STAAG Mk IV.

Note: It might be possible to complete some or all of the Batch 1 ships with the Type 965M radar with the AKE-1 aerial (or even the 965P with the AKE-2 aerial) because it entered service in 1958-59 on the Weapon class destroyers converted to interim fleet pickets and Ark Royal in her 1958-59 refit.

 

[NOMISYRRUC]

First Generation Anti-Submarine and General Purpose Frigates IOTL
Modernisations of the War Built Frigates and Conversions of the War Built Destroyers into Frigates​

They were exactly the same as IOTL in quantity and quality. That is unless a half-decent heavyweight anti-submarine torpedo was developed ITTL in which case all 23 Type 15s would have been fitted with 8 fixed torpedo tubes to fire them. If the Type 15 and Type 16 costs I quoted earlier in the thread were accurate then they’re cost effective as the cost one Type 12 (Whitby class) was the same as 5 Type 15 conversions and the cost of one Type 14 was the same as the cost of 10 Type 16 conversions.

Type 14 Blackwood class Second Rate Anti-Submarine Frigate​

12 were still built ITTL because they were cheap to build and due to their small crews cheap to run. As IOTL they served with the Portland Training Squadron and replaced the Algerine class minesweepers in the Fishery Protection Squadron. It could be argued (so I will) that they were replaced by the Island and Castle class offshore patrol vessels.

There were no improvements to their design and armament. However, as I want a half-decent heavyweight anti-submarine torpedo developed ITTL the ships keep their four 21in torpedo tubes in 2 twin trainable mountings.

IOTL Exmouth had her steam plant replaced by one Olympus and 2 Proteus gas turbines with the COGOG arrangement between 1966 and 1968. As suggested earlier in the thread she was completed with this machinery in 1957 ITTL for comparative trials with her half-sisters. The catalyst for this (as proposed earlier in the thread) was that the Captain class frigate Hotham was fitted with a gas turbine derived from an aero engine ITTL and the trials were successful enough to justify completing a Type 14 with gas turbines for further trials. IOTL the plan to fit Hotham with one bespoke English Electric EL60 gas turbine were abandoned in 1952 after shore trials showed that the plant was overweight and not flexible enough in operation.

Type 12 Whitby class First Rate Anti-Submarine Frigate​

6 were still built ITTL, but they had the broad-beam Leander hull. The ships were completed with twelve 21in torpedo tubes which IOTL were removed from all ships of the class by 1963. However, as I want a half-decent heavyweight anti-submarine torpedo developed ITTL they were retained.

They weren’t modernised IOTL but ITTL in they were modernised in the middle 1960s along the lines of the OTL Rothesay class modernisations of 1966-72. The differences were that:

• The Mk 6M director was replaced by an MRS.5 with the Type 905 radar instead of the MRS.3 with the Type 903 radar.
• Two STAAG Mk III twin Bofors L70 mountings were fitted instead of one Sea Cat.
• They kept six of the twelve 21in torpedo tubes.
• The Type 184 and 199 sonars were fitted. The latter is to please @Scott Kenny and is provided there was sufficient space and weight.
• The small ship version of ADA was fitted.

Type 12 Leander class General Purpose Frigate​

42 were built instead of the 9 Rothesay class, 7 Tribal class and the 26 Leander class built IOTL and there were a number of qualitative improvements:

• All 42 ships had the broad-beam Leander hull.
• All 42 ships were completed with the MRS.5 director with the Type 905 radar instead of the Mk 6M (Rothesay class) and the MRS.3 with the Type 903 radar on the Leanders & Tribals.
• All 42 ships were completed with two STAAG Mk III mountings. These took the place of the:
  • One Sea Cat system that the Rothesay class received in their 1966-72 refits;
  • Two Sea Cat systems that one Tribal class were completed with and the rest received in their 1967-74 refits;
    • and;
  • One Sea Cat system that 19 Leander class were completed with. (The OTL Leander was designed to have two Sea Cat systems.)
• All 42 ships were completed with one Type 965P radar with the AKE-2 aerial. IOTL the Rothesay class didn’t have a Type 965 while the Leanders & Tribals had the Type 965M with the AKE-1 aerial.
• All 42 ships were completed with six fixed 21in torpedo tubes for the half-decent heavyweight anti-submarine torpedo that I want to be developed ITTL.
  • IOTL the Rothesay class was designed to have 12 of them while the Leander & Tribal classes were to have 6 each.
  • However, most of the Rothesay class and all of the Leanders & Tribals were never fitted.
  • And they were removed from the Rothesays that actually had them fitted.
• The last 16 were completed with the small ship version of ADA and the first 26 received it in refits. This was planned for the Batch 2 and 3 Leanders of OTL but it wasn’t fitted.
• The ships that weren’t completed with the Type 184 and 199 sonars IOTL received them in refits ITTL. The Type 199 is to please @Scott Kenny.

Earlier in the thread I suggested building 42 Super Type 81 frigates instead of the Rothesay, Leander and OTL Tribal classes due to the trials with Hotham and Exmouth (see above) being successful ITTL. The ships would have had the OTL COSAG plant upgraded from 20,000shp to 30,000shp driving 2 shafts instead of one or an all GT plant (COGOG or GOGAG) producing at least 30,000shp and also driving 2 shafts. Both versions would have been fast enough to operate with fast carrier task forces. However, ITTL only one or two may have been built with gas turbines (COSAG or all GT), which in common with Exmouth, was for comparison with their steam powered half-sisters.

Modernisation was limited to enlarging the flight deck for the Lynx helicopter, mounting 4 Exocets on the quarterdeck and installing the Type 965 replacement that we want to enter service in the 1970s. The twin 4.5in mounting was retained, but the Limbo and Type 199 sonar were removed to make space for the Lynx helicopter and Exocets. (Sorry @Scott Kenny.) I can't decide whether this was done to all 42 ships or only the 26 built instead of the OTL Leander class.

 

[NOMISYRRUC]

The Type 42 was a mistake. The same equipment on a Type 22 hull would save money through economies of scale and allow upgrades. The Type 21 was also a mistake because it was not capable enough.

Different types of ship need different hull forms to be really effective. Brown & Moore touch on this a little in Rebuilding the Royal Navy.

What @starviking wrote plus half the Type 22s and all the Type 42s had the same machinery, 10 out of 14 Type 22s were built by Yarrow while the 14 Type 42s were split between Cammell-Laird, Swan Hunter, Vickers, Barrow & Vosper-Thornycroft so there isn't any scope for economies of scale through series production. Furthermore, we're well into the steel is cheap and air is free era so the cost of the hull is a small percentage of the cost of the ship in any case. That being written, the Americans built the Spruance class in one shipyard to get economies of scale and had AAW & ASW ships using a common hull & machinery been possible for the RN we might have got worthwhile savings by building all 36 hulls in one shipyard.

I think the Type 21 was a mistake too and that 8 Type 42s should have been built in their place even though they would have taken longer to build, cost more to build and required larger crews. Then build 8 extra Type 22s in place of the last 8 Type 42s of OTL so we end up with 22 Type 22s and 14 Type 42s instead of 8 Type 21s, 14 Type 22s and 14 Type 42s, that is the same number of hulls, but a significant increase in capability.

 

[Scott Kenny]

What @starviking wrote plus half the Type 22s and all the Type 42s had the same machinery, 10 out of 14 Type 22s were built by Yarrow while the 14 Type 42s were split between Cammell-Laird, Swan Hunter, Vickers, Barrow & Vosper-Thornycroft so there isn't any scope for economies of scale through series production. Furthermore, we're well into the steel is cheap and air is free era so the cost of the hull is a small percentage of the cost of the ship in any case. That being written, the Americans built the Spruance class in one shipyard to get economies of scale and had AAW & ASW ships using a common hull & machinery been possible for the RN we might have got worthwhile savings by building all 36 hulls in one shipyard.

The first trick is getting Treasury to accept that steel is cheap and air is free.

As to getting major production runs at a single yard, how many building slips do each yard have? While it would likely be best to have any given class built at a single yard, how many hulls can they build at one time?

As far as the different classes go, it may be better having the different yards each build a different class, if they have the building space to get as many going as needed.

Otherwise, I'm going to point you at the Japanese, who are regularly building their ships at 2 different yards.

 

[NOMISYRRUC]

AFAIK (1) the development of what became Seaslug and the "3-T" missiles began towards the end of World War II, but Seaslug didn't enter service until 1962 while Terrier entered service in 1955, followed by Talos in 1958 and Tatar in 1960. Meanwhile, Bloodhound the RAF's first SAM entered service in 1958 and Thunderbird the British Army's first SAM entered service in 1959.

Should Seaslug have taken so long to put into service?

AFAIK (2) the firms that produced Seaslug also produced Sea Dart. Therefore, if the former was put into service sooner, would the latter have entered service sooner too as a knock-on effect?

 

[zen]

Should Seaslug have taken so long to put into service?

Probably not, but events and uncertainty and the details of what sort of ship it would be integrated into, was in flux such that the County Class had a magazine system for the abortive Cruiser project.

Keep in mind navalisation was felt to add delay to the effort. Such that prior to commitment the Admiralty had investigated Thunderbird MkII.

AFAIK (2) the firms that produced Seaslug also produced Sea Dart. Therefore, if the former was put into service sooner, would the latter have entered service sooner too as a knock-on effect?

Errr....this is where NIGS became a problem first and if money and resources had been available from say '55 for a new missile system. Orange Nell would have been the priority.
While from '57 onwards NIGS is luring efforts away from a simpler Seaslug MkIII.

Edited in correction :
Counties had the Destroyer missile magazine system. I had miss-read my books and it was the trials ship Girdle Ness that had this.
In fact this may even be part of why the County Class and Seaslug took so long to enter service. Having to design and build the alternative magazine system.

 

[Rule of cool]

Is the 'steel is cheap, air is free' mantra appropriate in the era of steam propulsion where the firebox has to be re-lined at great expense with brick/tiles at ever deceasing intervals, starting at 12 years, then 6-4-3-3? Obviously the refit lasting 6 years is decent value for money, and the one lasting 4 years likely is as well but when these expensive refits happen every 3 years at year 22 or so the fact that the hull can last 30 years isn't very relevant. This was such a driver of cost that apparently the RN considered making a boiler that could last 16 years and then scrapping the ship when that time was up.

In contrast Gas Turbines last for ages and are 'repair by replacement', simply swap a faulty one out in short order without a long and costly refit. When machinery is no longer such a driver of costs then I think the mantra becomes viable, but that's just my conclusion.

 

[uk 75]

I have always wondered whether the RN tried too hard to have its own versions of US systems.
Seaslug is comparable with Terrier and the County class similar to the US Coontz class (star of The Bedford Incident).
NIGS is designed to do the same job as the US Talos but on a smaller hull.
CF299/Seadart is a Tartar designed originally to fit a Type 12 frigate.
But the RN then goes its own way with point defence missiles. Neither Seacat (based on the Malkara ATGW) or Seawolf (no Western equivalent) have US counterparts once Sea Mauler is scrapped. Sea Chapparal and Seasparrow fall neatly between the two UK systems.

 

[Dilandu]

I have always wondered whether the RN tried too hard to have its own versions of US systems.
Seaslug is comparable with Terrier and the County class similar to the US Coontz class (star of The Bedford Incident).
NIGS is designed to do the same job as the US Talos but on a smaller hull.
CF299/Seadart is a Tartar designed originally to fit a Type 12 frigat

It would be more correct to say. that RN agreed with USN's overral concept of missile-based fleet defense, but not with the specific designs of American missiles. If I recall correctly, among the many reasons why RN didn't want "Terrier", was that it's missiles are far too long to be manually reloaded in case of battle damage (a quite dubious assumption that mechanic of reloading system could be knocked out, but the much more fragile electronic of guidance system would continue to function).

 

[CV12Hornet]

Is the 'steel is cheap, air is free' mantra appropriate in the era of steam propulsion where the firebox has to be re-lined at great expense with brick/tiles at ever deceasing intervals, starting at 12 years, then 6-4-3-3? Obviously the refit lasting 6 years is decent value for money, and the one lasting 4 years likely is as well but when these expensive refits happen every 3 years at year 22 or so the fact that the hull can last 30 years isn't very relevant. This was such a driver of cost that apparently the RN considered making a boiler that could last 16 years and then scrapping the ship when that time was up.

In contrast Gas Turbines last for ages and are 'repair by replacement', simply swap a faulty one out in short order without a long and costly refit. When machinery is no longer such a driver of costs then I think the mantra becomes viable, but that's just my conclusion.

You're going to need to elaborate on your reasoning, because I'm not following it. "Steel is cheap and air is free" is a mantra usually applied to acquisitional costs, not operating.

 

[Scott Kenny]

You're going to need to elaborate on your reasoning, because I'm not following it. "Steel is cheap and air is free" is a mantra usually applied to acquisitional costs, not operating.

Having larger hulls makes maintenance easier because some engineer didn't have to stuff a system into some odd nook that then takes 30 hours of disassembly to access to push a reset button or clean a filter.

 

[Rule of cool]

You're going to need to elaborate on your reasoning, because I'm not following it. "Steel is cheap and air is free" is a mantra usually applied to acquisitional costs, not operating.

As I understand it with steam propulsion the powerplant weight is more closely linked to overall displacement than it is with the much lighter Marine GTs. To make a steam powered ship bigger will mean a commensurate increase in the size and weight of the steam plant. I recall reading that the reason the CVA01 was 53,000t was because that could be done on 3 shafts and powerplant whereas to go 58,000t would have required a 4th shaft and commensurate machinery and the tactical advantage was not equal to the extra cost.

In contrast the 3,300t Type 21, 4,300t Type 42 B1&2, 5,200t Type 42 B3, 4,400t Type 22 B1 and 4,800t Type 22 B2 all used the same Olympus/Tyne COGAG powerplant. The ~20,000t Invincible used double the 'boost' powerplant of these smaller ships despite being 4 times the size.

As I understand it 'steel is cheap, air is free' is all about making ships big enough to be upgrade-able throughout their hull life. In the steam era the hull life wasn't as important as the re-lining cycle for the boilers, so getting that extra decade through upgrades wasn't seen as practical. Its also important to keep in mind that in the steam era electronics weren't as big a driver of cost as they did as GTs were adopted, by the time GTs were the standard propulsion electronics were a huge part of the ship's cost.

 

[Dilandu]

In contrast the 3,300t Type 21, 4,300t Type 42 B1&2, 5,200t Type 42 B3, 4,400t Type 22 B1 and 4,800t Type 22 B2 all used the same Olympus/Tyne COGAG powerplant. The ~20,000t Invincible used double the 'boost' powerplant of these smaller ships despite being 4 times the size.

It also allow for much greater powerplant unification than for steam power.

 

[CV12Hornet]

As I understand it with steam propulsion the powerplant weight is more closely linked to overall displacement than it is with the much lighter Marine GTs. To make a steam powered ship bigger will mean a commensurate increase in the size and weight of the steam plant. I recall reading that the reason the CVA01 was 53,000t was because that could be done on 3 shafts and powerplant whereas to go 58,000t would have required a 4th shaft and commensurate machinery and the tactical advantage was not equal to the extra cost.

In contrast the 3,300t Type 21, 4,300t Type 42 B1&2, 5,200t Type 42 B3, 4,400t Type 22 B1 and 4,800t Type 22 B2 all used the same Olympus/Tyne COGAG powerplant. The ~20,000t Invincible used double the 'boost' powerplant of these smaller ships despite being 4 times the size.

As I understand it 'steel is cheap, air is free' is all about making ships big enough to be upgrade-able throughout their hull life. In the steam era the hull life wasn't as important as the re-lining cycle for the boilers, so getting that extra decade through upgrades wasn't seen as practical. Its also important to keep in mind that in the steam era electronics weren't as big a driver of cost as they did as GTs were adopted, by the time GTs were the standard propulsion electronics were a huge part of the ship's cost.

Making ships big enough to be upgradeable through their lifespans is only one of the reasons for the "steel is cheap and air is free" mantra. In the case of the British it's the case that they kept building their ships too small for arbitrary reasons that did little to reduce cost. The Type 42s are a good example - the Batch 1 & 2 ships were made smaller than desired for economy reasons that only hampered the ships for minimal cost reductions, resulting in Batch 3 being the size they actually should've been.

There's also the fact that even as early as the 1950s ships are increasingly volume-critical, not displacement-critical. That is, the obstacle to adding new equipment to a design is not how much it and the supporting structure weighs, but how much space it takes in. So the all-out need to shave weight is a lot less important now.

But circling back to upgradeability, the boiler cycle does not prevent upgradeability from being a desireable quality in ships. Even in the late 1940s/early 1950s the Brits were looking at a 26-year lifespan for their steam-powered escorts - 16 years as designed and then a mid-life refit to add another ten years. That mid-life refit is the key point here - ideally, you'd want the space and weight margins to add new equipment and keep the ship technologically relevant, especially for a Navy like Britain struggling to replace ships even then. Consider also the interwar era ships, who due to tight design margins under the treaty regime lacked the space and weight margins for necessary WW2-era upgrades.

 

[Rule of cool]

Making ships big enough to be upgradeable through their lifespans is only one of the reasons for the "steel is cheap and air is free" mantra. In the case of the British it's the case that they kept building their ships too small for arbitrary reasons that did little to reduce cost. The Type 42s are a good example - the Batch 1 & 2 ships were made smaller than desired for economy reasons that only hampered the ships for minimal cost reductions, resulting in Batch 3 being the size they actually should've been.

There's also the fact that even as early as the 1950s ships are increasingly volume-critical, not displacement-critical. That is, the obstacle to adding new equipment to a design is not how much it and the supporting structure weighs, but how much space it takes in. So the all-out need to shave weight is a lot less important now.

But circling back to upgradeability, the boiler cycle does not prevent upgradeability from being a desireable quality in ships. Even in the late 1940s/early 1950s the Brits were looking at a 26-year lifespan for their steam-powered escorts - 16 years as designed and then a mid-life refit to add another ten years. That mid-life refit is the key point here - ideally, you'd want the space and weight margins to add new equipment and keep the ship technologically relevant, especially for a Navy like Britain struggling to replace ships even then. Consider also the interwar era ships, who due to tight design margins under the treaty regime lacked the space and weight margins for necessary WW2-era upgrades.

We're the volume limited 50s ship during the transition to bulky SAMs and their launchers, computerised CICs and helicopters? If so the ship designers can be cut a bit of slack for not getting the transition 100% right.

The Type 42 are the perfect example of the mantra being suited to GT ships. The Type 42s could not have been successfully stretched in their power plant was sized for the smaller ship.