Rn vs IJN

[EwenS]

The larger between the wars Cruisers were supposed to carry up to 3 aircraft. The Swordfish and Shark were both float capable. The specs called for the Albacore but I am not sure it went anywhere.
View attachment 733210
Not sure if the catapult would handle the load. The idea getting the torpedo to the catapult might have given the officers tasked with carrying out the move the heebie-jeebies

Sometimes you have to decide what the mission/s are and stick with them. Using 3-4 planes as a strike group needs a lot of luck. it also needs a dedicated magazine and/or dedicated bomb lifts. Which affect both water and fire spread integrity. Most Cruisers had enough trouble flying the planes as recon planes unless you are willing to write off the crews.

Might have been desperation. Since the Japanese AA pretty much sucked maybe using the F1M was more effective than using the ships own AA?

Most British cruisers were designed, or refitted, to carry 1-3 floatplanes/amphibians from the late 1920s. But the types of catapult, their method of mounting and their launching capacities varied considerably until the Towns. Hangars to protect them were introduced with the Town class designed in 1933 and later fitted to 4 of the Kent class in mid-1930s refits. By the late 1930s the cruiser aircraft were Fairey Seafox on the smaller ships and Walrus on the larger. Swordfish by then went to the Battleships.

The main purpose for them was for recce to expand the horizon when the cruiser was operating alone on the sealanes, and then to provide gunfire spotting once an enemy was found. But ASW was added later (Warspite's Swordfish sank a U-boat in 1940 in a Norwegian fjord).

The floatplane Albacore never got beyond the prototype stage nor did the Roc. The successor to the Walrus was intended to be the Sea Otter but its introduction to service was delayed by the war.

The Tone class (and the later Mogami conversion) and the Oyodo (and her never built sister Niyodo) were unique to the IJN. The former were to provide recce for the fleet so freeing carrier aircraft for the offence, and the latter for the sub flotillas.

Carrying aircraft was a dangerous business. Liverpool was torpedoed forward in 1940 and that triggered an explosion of her petrol storage tank that effectively resulted in her losing her bow back to A turret. Newcastle came close to having a similar problem in 1942. That is the petrol tank in the middle of the hole!

 

[RCAFson]

Which escorts are you thinking about?

The Flower class were mainly built in mercantile yards not the big naval yards. The exception was Harland & Wolff in Belfast who dedicated 2 slips to their production on an almost production line basis from the outbreak of war.

Production of Black Swan class sloops would probably have continued at a rate of a couple per year. But the increased production of the 1940/41 Programmes built in the smaller naval yards weren't laid down until 1941 and it was late 1942 before these began to appear historically.

The big programme affecting the naval yards were the Hunt class escort destroyers in the various 1939 and 1940 Programmes (86 ships completed through to 1943) and the various Intermediate destroyers of the 1939 War through 1942 Programmes (2,4,5 & 3 flotillas per year, total 112 ships completed through to 1947). But in the absence of these ships in the yards there would have been some kind of replacement to follow on from the L&M classes. The pattern from the mid-1930s had been to order 2 flotillas, total 16 ships, per year (except for 1938 when none were included). ISTR seeing a design with 4 turrets of the L class. But the problem was the complexity and cost of these large destroyers resulting in the N class in 1939 as a repeat J/K to keep cost down. But there was the need to tackle ships like the large Japanese destroyers.

IIRC, it wasn't the yards but the supply of labour, especially skilled labour. Given the rapid expansion of the Army, and RAF after Dunkirk there wasn't enough workforce to provide labour to the shipyards. Frequent air raids didn't help either, along with competition with the Army and RAF for steel, armour, armaments and FC instruments:

The Two-Power Navy and Emergency Programmes
As a result of the crisis and of the new mood which it induced the Admiralty was at last able to grasp the final object of its desires and to plan for a 'two-power standard'.8 The discussions which went on throughout the late months of 1939 (1938?) and the first half of 1939 culminated in July 1939 in a decision of the Committee of Imperial Defence authorising the development of additional machine tools in preparation for a new scale of construction. After August financial objections to the attainment of a 'two-power standard' rapidly disappeared, and broadly speaking the Admiralty then set out to attain that standard as a long-term policy.9 [ 9 This required by 1942 among other fleet vessels two additional capital ships over and above the nineteen previously sanctioned, seventeen additional cruisers over the eighty-three already provided for, two additional aircraft carriers and five additional flotillas of destroyers.]

The main issue of the Admiralty's battles was thus won, yet at the time of its winning it had lost much of its immediate value. The 'two-power standard' from now on remained the long-term programme of the Navy, but in the months following Munich, and still more in the opening phases of the war itself, long-term programmes were very much a matter of theory. Their emphasis was on fleet units, in which this country had a great superiority over Germany, whereas what was urgently wanted was small vessels for convoy-escort and anti-submarine duties, of which the Navy was very short. Although plans for ocean convoys were far advanced by April 1939 they were not as yet put into operation. The prevailing assumption still was that the enemy would keep the Hague Convention, would limit mining warfare to moored mines and would not resort to unrestricted submarine warfare. On these assumptions anti-submarine convoys would be required only in coastal waters and in a few focal areas. Yet even so, the Navy, according to Admiralty estimates, would still need as a minimum some 1,110 trawlers and 300 escort vessels and minesweepers of which only about two-thirds were provided for in the current programmes. The small ships were therefore bound to be become the first charge on the immediate programme, and in its emergency plans the Admiralty accordingly laid down that in the first year of war shipbuilding resources should be so employed as to leave enough for the small ship programme as well as for an annual output

--58--

of 1.2 million gross tons of merchant shipping. And to make this possible the building of fleet units was to be considerably slowed down.10

With the outbreak of the Navy's emergency plans had to be carried a stage further, and provision had to be made for a still larger number of small vessels. The need could to some extent be met by converting merchant vessels and by employing mercantile yards, but some small vessels had to be constructed in naval shipyards, and their number could not be increased without prejudicing the output of fleet units. Towards the end of the first month of war the Admiralty realised that its requirements of small vessels had been somewhat unrealistic. Not only were fewer auxiliary vessels capable of being diverted from their civilian uses, but the need for small vessels was more exacting than it had appeared a year earlier. Magnetic mines demanded ships differently equipped from any previously built German submarines were more active around the coast, and this led to a higher demand for small anti-submarine boats and anti-submarine vessels of the trawler type. But the chief new factor was the activity of German ocean-going U-boats along the Atlantic routes, and this meant that at least another 100 additional escort vessels of longer range than the corvettes were needed to operate them both ends from the middle of the Atlantic and thus to provide a continuous convoy across the ocean. Requirements of other small craft also rose—the Admiralty now wanted more submarines (about 100), more M.T.B.s (about 84), more boom defence vessels, salvage vessels, and tugs. In contrast to these short-term requirements of trade protection vessels, requirements of fleet units were much less urgent and did not materially increase, with the important exception of destroyers. Indeed, in order to provide for additional minesweepers and anti-submarine flotillas and to release steel for the merchant shipbuilding programme, and Admiralty agreed in March 1940 to sacrifice the whole of the 1940 share of the long-term programme of naval construction. The only major fleet units still to be built were the Vanguard (because of the shortage of fast battleships) and two flotillas of destroyers—and the latter could of course be considered as part of the short-term programme.

The programmes of naval construction as well as its problems remained in essence the same until the end of 1941; the differences were merely those of scale. Above all, the emergency programmes of small vessels continued to be the main preoccupation of the Admiralty and of the shipping industry for a number of years. It will consequently be convenient to carry the story of naval construction to Pearl Harbor without a break.

--59--

Although the Admiralty was compelled to devote much of its time and attention to the emergency programmes, its hopes for larger units were not lightly abandoned and attempts to resume the 'long-term' programmes of naval construction were made from time to time. The fall of France and the extension of war to the Mediterranean threatened to wipe out what had hitherto been a comfortable superiority over the enemy in fleet units. British superiority in large ships over the combined Italian and German fleets was only assured until the summer of 1942. There was also the possibility of the French fleet joining the enemy; and in addition the situation in the Far East was very uncertain. It was obviously becoming dangerous to neglect the large ships altogether in favour of light craft, and both the Admiralty and Mr. Churchill's Government could be relied upon to see the danger.

Nevertheless hopes of resuming the construction of large vessels were to prove illusory, for even while the doctrine of a balanced fleet was reviving in high quarters, the emergencies on the high seas were compelling further diversion of resources to the small vessel programmes. In the autumn of 1940 and the spring of 1941 it was found necessary to provide escorts for troop convoys to the Middle East by the long Cape route and to counteract new enemy techniques and weapons such as the laying of improved types of mine, the use of E-boats in the Channel and of midget submarines in the Mediterranean. No wonder small vessel programmes failed to tail off as they were expected to do. Requirements between Dunkirk and Pearl Harbor varied with the development of enemy tactics, and for one class of vessels, i.e. trawlers, requirements actually fell. But the estimated requirements of most other classes of small vessels grew in the course of 1940 and 1941 and stood higher in the autumn of 1941 than in the summer of 1940.11

It was not, however, the emergency programmes alone that prevented the resumption of a 'balanced fleet' programme. Even before the Admiralty took over direct responsibility for the construction of merchant ships12 the needs of merchant shipbuilding were very heavy and interfered with some parts of the naval programmes. At least as burdensome and in very way as urgent were the mounting totals of repairs and conversions.

the burden of repairs was perhaps all the heavier for being somewhat unforeseen, or to be exact, greater than the planners could foresee. From the very outbreak of war the dockyards found themselves overwhelmed with ships sent for refit or repairs. In the

--60--

opening months of war the accident rate, chiefly caused by weather and collisions (by the end of 1939 one hundred and eleven ships had bee damaged by accidents compared with twenty by enemy action), was very high indeed and, on the average, well over 100 naval vessels were in hand for refit or repairs at any one time. In 1940 damage from weather and accidents declined, but in the end the decline was more than made up for by a very steep rise in the damage rate from enemy action—a rate which began to grow in the Norwegian campaign, was greatly swelled by Dunkirk, and was kept high by hostilities in the Mediterranean. During 1940 470 naval ships were damaged, nearly half from enemy action, and in 1941 the rate of damage from enemy action, especially in the Mediterranean, rose still higher. On the average about 146 naval vessels were in hand for refit or repair at the end of each months in the first quarter of 1941, and the figure rose to 166 in the last quarter of the year. Added to this, a large number of French and Allied ships and the fifty American destroyers13 had to be partly or wholly refitted.

HyperWar: British War Production [Chapter III]

www.ibiblio.org

Canadian and other Commonwealth nation's production would, of course, have risen considerably as well, but it wasn't till ~1942 that it could start to plug many of the gaps in UK production, with the notable exception of trucks.

 

[EwenS]

IIRC, it wasn't the yards but the supply of labour, especially skilled labour. Given the rapid expansion of the Army, and RAF after Dunkirk there wasn't enough workforce to provide labour to the shipyards. Frequent air raids didn't help either, along with competition with the Army and RAF for steel, armour, armaments and FC instruments:

Yes labour was a problem, especially specialist trades like electricians, demand for which increased throughout the war as systems became more complex. But shipbuilding was a reserved occupation from 1938 so labour there was exempt from conscription. Having a larger pool of unskilled labour means a large training programme to get the additional shipyard workers required. That doesn't happen overnight.

But labour was only one of many bottlenecks. Lack of manufacturing capacity for armour was another, with large quantities having to be ordered from Czechoslovakia and being delivered right up to Aug 1939. The Admiralty paid to expand production but it all took time. Also gun and mounting production, particularly the latter where the capacity of the industry only allowed 2 Battleships per year plus a third every 2/3 years. During WW2 they paid to reopen the gun pits at the Harland & Wolff plant (ex COW) on the Clyde to refurbish the turrets for Vanguard.

But with no threat of war in Europe how much of this expansion gets delayed or just never happens.

Canadian and other Commonwealth nation's production would, of course, have risen considerably as well, but it wasn't till ~1942 that it could start to plug many of the gaps in UK production, with the notable exception of trucks.

Warship building capacity in the Dominions pre-war was exceptionally limited. Canada had to order Tribals from Britain in 1939/40 since it didn't have the ability to build them at home until 1942 through experience built up building simpler ships like the Flower class.

Australia built nothing bigger or more complex than a Tribal class destroyer from late 1939. Its capacity might have allowed construction of one cruiser at a time.

India built nothing bigger than a minesweeper in WW2 and even then was importing much from Britain, including the machinery.

And without the immediate prospect of a war do the Dominions have the political will to spend more money on defence? Inter war they were relying heavily on Britain to defend them on the high seas.

 

[RCAFson]

Yes labour was a problem, especially specialist trades like electricians, demand for which increased throughout the war as systems became more complex. But shipbuilding was a reserved occupation from 1938 so labour there was exempt from conscription. Having a larger pool of unskilled labour means a large training programme to get the additional shipyard workers required. That doesn't happen overnight.

But labour was only one of many bottlenecks. Lack of manufacturing capacity for armour was another, with large quantities having to be ordered from Czechoslovakia and being delivered right up to Aug 1939. The Admiralty paid to expand production but it all took time. Also gun and mounting production, particularly the latter where the capacity of the industry only allowed 2 Battleships per year plus a third every 2/3 years. During WW2 they paid to reopen the gun pits at the Harland & Wolff plant (ex COW) on the Clyde to refurbish the turrets for Vanguard.

But with no threat of war in Europe how much of this expansion gets delayed or just never happens.

Warship building capacity in the Dominions pre-war was exceptionally limited. Canada had to order Tribals from Britain in 1939/40 since it didn't have the ability to build them at home until 1942 through experience built up building simpler ships like the Flower class.

Australia built nothing bigger or more complex than a Tribal class destroyer from late 1939. Its capacity might have allowed construction of one cruiser at a time.

India built nothing bigger than a minesweeper in WW2 and even then was importing much from Britain, including the machinery.

And without the immediate prospect of a war do the Dominions have the political will to spend more money on defence? Inter war they were relying heavily on Britain to defend them on the high seas.

Of course the need to build thousands of tanks also complicated the armour supply problem.

Canada had embarked upon a naval expansion program pre-war and planned to expand the RCN to 16 fleet destroyers and the threat of war with Japan would have given that expansion plan additional impetus. Australia had similar plans and even more incentive. Canada did have a considerable latent ship building capacity and it was sufficient to have enabled the UK to focus more on fleet warships and less on escorts, with a net increase in BCE naval power.

Cdn maritime production during WW2:

• 348 -Fort and Park 10,000 ton Cargo ships
• 43 -Gray and Dominion 4,700 ton Cargo Ships
• 6 -3,600 ton Tanker Ships
• 4 -Destroyers
• 70 -Frigates
• 122 -Corvettes
• 210 -Minesweepers
• 27 -Motor Torpedo Boats
• 88 -Fairmille Motor Launches
• 330 -Tug Boats

• Ships For Victory -Can Canada Build Ships Today | Roger Litwiller

  This past week marked an incredible milestone in Canadian shipbuilding history. On 20 September 1943, twelve Canadian built

  www.rogerlitwiller.com

 

[Thumpalumpacus]

Of the 13 County class, Sussex was under long term repair from Sept 1940 to Aug 1942 having been bombed during the blitz on Glasgow.

While Britain never built another 8" cruiser after completing the Exeter in 1931, they did not give up on the idea. There were plans for a new "Admiral" class with 9x8" (3x3) from about 1938/39 to Oct 1942, but WW2 meant the resources could not be spared to build them. Courtesy of Churchill, in 1939/40 there was even a short lived suggestion (I wouldn't even call it a serious proposal, let alone a plan, because it was shot down so quickly by the Admirals!) for a 9.2" armed cruiser.

Of the 10 Towns (Southampton - Edinburgh classes), 2 had been sunk by late 1941 and Belfast was under long term repair between Nov 1939 and Oct 1942 having been mined. Manchester was under repair July 1941 to May 1942 first in the USA then Britain, with torpedo damage.

Fiji class 5 completed by end of 1941 with 1 lost.

Then there were routine refits and lesser repairs for weather and / or action damage to figure into the numbers equation. Mauritius (Fiji class) for example was in refit at Singapore from Nov 1941 but on outbreak of war with Japan was immediately undocked and sent home only to complete the refit in April 1942.

Ewen, didn't the Town-class have fast-firing batteries? Or was that the Crown Colonies? And how might that change the equation against IJN?

 

[ThomasP]

I think we have to assume that there is an impetus for the UK/Commonwealth to go on a war footing as far as preparing for war in the Far East. We are assuming that the UK still has its intelligence network, and the intent to complete Singapore as a forward naval base/stronghold. The Admiralty would understand the problems involved re the extreme range to the theater.

As such I think the question is not whether they would gear up for war at the same rate, but what would change as far as allocating resources for the Far East war as opposed to what was done historically for the ETO/MTO.

One example that I think would apply involves the number of small[ish] escorts built for the war in the Atlantic. Would it make sense to build anywhere near the same number of Flower class corvettes? What would the chosen escort design be for the Far East? Japan did not plan on fighting using unrestricted submarine warfare, but how much would the Admiralty have incorporated that information in their plans?

Another example is the Fairmile B ML. They were not war winners, but they served a useful purpose in coastal waters and as inner zone escort ASW & gunboats, and they were designed to be deployable under their own power (with use of sail if necessary) to the farthest reaches of the Empire - bringing their own spares with them.

Still another small example is the Bombay bomber/transport. Its Air Ministry Specification specifically called for the ability to transport small numbers of Sqn personnel and spares (including a spare engine) over long distance for deployment/reinforcing purposes. They even had preset packages designed for transport, for the minimal level airfield construction necessary.

What about flying boats? The Sunderland was a good aircraft, but was it what they would have built if they were planning on going to war in the Far East? (I am not saying it was not appropriate, just that it might not have been the best they could have built for the Far East.)

A bigger issue (perhaps) that has been discussed elsewhere in the forum and on many other forums, is what would be the form of the new build carriers - improved Ark Royals, same or similar to the Illustrious class, or something significantly different?

And the destroyer flotillas. After a point in time, would they have continued to build the shorter range hulls of the G/H and J classes, or would they have switched to a longer range hull similar to the Tribal and L/M classes?

etc.

 

[EwenS]

Ewen, didn't the Town-class have fast-firing batteries? Or was that the Crown Colonies? And how might that change the equation against IJN?

It was the same 6"/50 gun that was used in all the cruiser classes from the Leanders to the Minotaur/Swiftsure completed 1944/45. Only the nature of the turrets changed. Twin Mk.XXI (Leander/Arethusa) and triple Mk.XXII (Town class first 8 ships) had a "short trunk" turret. Charges and shells were moved from magazines to handling rooms beneath the turret, and then on other hoists into the turret. The Mk.XXIII "long trunk" turret was fitted in later classes (Town class last two ships / Edinburgh group, Fiji / Crown Colony & Minotaur / Swiftsure). In this turret the charges and shells were hoisted from magazines direct into the turrets with a manpower saving. I don't think there was much difference in rate of fire per barrel between turret types.

The theory behind all the nations cruisers armed with triple 6" guns from the early 1930s was that sheer weight of fire from 12/15 6" barrels would overwhelm an enemy (more hits each casing less damage) whereas the heavier 8" shells would result in fewer hits each causing more damage. But the need for such ships came out of the London Naval Treaty 1930. It split cruisers into two categories:-

1. Cruisers with guns greater than 6.1"
2. Cruisers with guns not greater than 6.1"

The first group was limited both by total tonnage AND by the number of ships permitted. So USN/RN/IJN was 18/15/12, and both the RN and IJN had already built to these limits (the RN actually needed to convert/disarm/scrap the Hawkins class by the end of 1936 to comply). The US got more ships in this category by special pleading.

The second group had an overall tonnage cap only. So you could have a lot of smaller cruisers or a lesser number of larger ships.

The RN thought that this would limit cruiser size to around the size of a Leander. In fact it didn't because the Japanese built the Mogami class with 15x6.1" forcing a new cruiser race of 9,000-10,000 ton ships armed with a generally larger number of guns than previously. But for the RN the issue was numbers so they limited the Towns to 12 guns. The Edinburgh sub group were initially planned to have 16x6" in 4 quad turrets. The US built the Brooklyn class in response.

That was why the 1936 London Treaty sought to limit ship size rather than total tonnage to help the RN with its need for numbers.

The Mogami class were designed from the outset to be upgradeable to 8", which is what happened after the Japanese quit the Treaty system.

Article XVI 1. The completed tonnage in the cruiser, destroyer and submarine categories which is not to be exceeded on 31 December 1936 is given in the following table:​
Maximum quantity of cruisers, destroyers and submarines allowed to each nation	Categories​ United States​ British Commonwealth of Nations​ Japan​ Cruisers: ​ ​ ​ (a) with guns of more than 6.1 inch (155 mm) calibre 180,000 tons (182,880 metric tons)​ 146,800 tons (149,149 metric tons)​ 108,400 tons (110,134 metric tons)​ (b) with guns of 6.1 inch (155 mm) calibre or less 143,500 tons (145,796 metric tons)​ 192,200 tons (195,275 metric tons)​ 100,450 tons (102,057 metric tons)​ Destroyers 150,000 tons (152,400 metric tons)​ 150,000 tons (152,400 metric tons)​ 105,500 tons (107,188 metric tons)​ Submarines 52,700 tons (53,543 metric tons)​ 52,700 tons (53,543 metric tons)​ 52,700 tons (53,543 metric tons)​
Details of how the tonnage is assigned	2. Vessels which cause the total tonnage in any category to exceed the figures given in the foregoing table shall be disposed of gradually during the period ending on 31 December 1936. 3. The maximum number of cruisers of sub-category (a) shall be as follows: for the United States, eighteen; for the British Commonwealth of Nations, fifteen; for Japan, twelve. 4. In the destroyer category not more than sixteen percent of the allowed total tonnage shall be employed in vessels of over 1,500 tons (1,524 metric tons) standard displacement. Destroyers completed or under construction on 1 April 1930 in excess of this percentage may be retained, but no other destroyers exceeding 1,500 tons (1,524 metric tons) standard displacement shall be constructed or acquired until a reduction to such sixteen percent has been effected. 5. Not more than twenty-five percent of the allowed total tonnage in the cruiser category may be fitted with a landing-on platform or deck for aircraft. 6. It is understood that the submarines referred to in paragraphs 2 and 3 of Article 7 will be counted as part of the total submarine tonnage of the High Contracting Party concerned. 7. The tonnage of any vessels retained under Article 13 or disposed of in accordance with Annex II to Part II of the present Treaty shall not be included in the tonnage subject to limitation.​

 

[EwenS]

A lot to unpick here

I think we have to assume that there is an impetus for the UK/Commonwealth to go on a war footing as far as preparing for war in the Far East. We are assuming that the UK still has its intelligence network, and the intent to complete Singapore as a forward naval base/stronghold. The Admiralty would understand the problems involved re the extreme range to the theater

Pre-war RN policy was to assemble a fleet to be sent east to Singapore in time of crisis. The time for this grew over time. And if the fleet needed to move forward the plan included provision for a forward base somewhere. And any action in the Far East being planned was predicated on Singapore remaining in British hands.

But range wasn't really an issue for the RN in getting there. It held oil stocks at Gibraltar, Malta, Alexandria, Aden and Trincomalee. In fact Trincomalee had the greatest overseas storage capacity of any place except Singapore. After that it was only about 2,000 miles to Hong Kong and another 1,000 to southern Japan. And the main source of replacement stocks was the refinery at Abadan at the head of the Persian Gulf. And Britain had access to a large civilian tanker fleet to move it all around.

This might prove interesting to some of you

https://kclpure.kcl.ac.uk/ws/portalfiles/portal/2932258/408161.pdf

As such I think the question is not whether they would gear up for war at the same rate, but what would change as far as allocating resources for the Far East war as opposed to what was done historically for the ETO/MTO.

One example that I think would apply involves the number of small[ish] escorts built for the war in the Atlantic. Would it make sense to build anywhere near the same number of Flower class corvettes? What would the chosen escort design be for the Far East? Japan did not plan on fighting using unrestricted submarine warfare, but how much would the Admiralty have incorporated that information in their plans?

Geography plays a major part here. With the RN at Singapore IJN sub activity is not going to be able to penetrate the outer island barrier of the DEI and into the Indian Ocean. So the requirement for escort ships for convoy work without a war in Europe is minimal. It perhaps extends to escorting any fleet train supporting the fleet at sea.

Design of the Flowers, Rivers & Lochs and the US DE was driven by the U-boat war in the Atlantic. It wasn't until 1944/45 that the Loch hull was adapted to war in the Far East to produce the Bay class. Without war in Europe you would see a continuation of Black Swan production at low levels. It was the culmination of 10 years of sloop development. Well armed against both air and submarine attack and with more range than the faster Hunt class with similar armament. They were more complex to build and were a product of the smaller naval yards. But despite everything else they continued to be built throughout the war. And most importantly proved capable of taking a much heavier AA battery and radar equipment as time went on. At one point there was a trade off between these and a small batch of Hunts.

Another example is the Fairmile B ML. They were not war winners, but they served a useful purpose in coastal waters and as inner zone escort ASW & gunboats, and they were designed to be deployable under their own power (with use of sail if necessary) to the farthest reaches of the Empire - bringing their own spares with them.

These didn't need to be built in Britain. In fact considerable numbers of Fairmile ML and HDML were built in yards throughout the Indian Ocean area from South Africa, East Africa, India, Burma (Rangoon) and beyond to Singapore, Hong Kong, Australia & New Zealand. Probably the only things needing to come from Britain would be engines and / or armament

Still another small example is the Bombay bomber/transport. Its Air Ministry Specification specifically called for the ability to transport small numbers of Sqn personnel and spares (including a spare engine) over long distance for deployment/reinforcing purposes. They even had preset packages designed for transport, for the minimal level airfield construction necessary.

The troop carrying requirement was built into most the British bomber specs of the period including B.12/36 that led to the Stirling and B.13/36 that led to the Manchester and Halifax. IIRC it was the last of several requirements to be dropped from the Manchester design around 1939/40.

What about flying boats? The Sunderland was a good aircraft, but was it what they would have built if they were planning on going to war in the Far East? (I am not saying it was not appropriate, just that it might not have been the best they could have built for the Far East.)

The Sunderland spec (R.2/33) emerged from OR.8 in 1933 for a long range monoplane flying boat to replace various biplane types then in service with the RAF throughout the world (e.g. Short Singapore, Sara London etc). But with the relaxed peacetime pace of aircraft development it didn't fly until Oct 1937.

June 1938 saw the first production aircraft flown out to Singapore to join 230 squadron. By Sept 1939 about 40 were in service with squadrons at Alexandria (228), Singapore (230) and at home (204, 210 & 10 RAAF). Range of the Mk.I at cruising speed was 2,880 miles (178mph at 2,000ft). (Data from "Ocean Sentinel. The Short Sunderland" by John Hamlin). Its predecessor in the Far East was the Short Singapore III with a range of 1,000 miles. For what I have to hand that was better than the early PBY-5 Catalina aircraft.

A bigger issue (perhaps) that has been discussed elsewhere in the forum and on many other forums, is what would be the form of the new build carriers - improved Ark Royals, same or similar to the Illustrious class, or something significantly different?

And the destroyer flotillas. After a point in time, would they have continued to build the shorter range hulls of the G/H and J classes, or would they have switched to a longer range hull similar to the Tribal and L/M classes?

etc.

As for destroyers things changed in the mid-1930s. First the Tribals with heavy gun armament as a response to the Japanese Fubuki class. Then a reversion to the J & K with 6 guns v 8 but more torpedo tubes (10 v 4). The L/M brought a new 4.7" gun with a heavier 62lb shell in an enclosed gunhouse. But there destroyer development stops dead due to the European war being imminent. The range figures for the Tribals to M classes are all pretty similar. An improvement was made from the Q class forward by trading ammunition forward (half the guns so less need) for extra fuel.

Hunts were really of little use in the Far East due to a lack of range. The Intermdiate O-C classes were a race for numbers under wartime conditions (first orders 4 Sept 1939 in accordance with pre-war planning - effectively a G class for rapid production avoiding bottlenecks of gun mounting production for more complex L/M class mounts).

The fly in the ointment come 1938/39 was money. It was one reason for the N class in the 1939 Programme rather than a successor to the M class. But with no Flowers or Hunts more should be available for a new class of destroyer.

Edit:- to change the direction of carrier design you need to go back to 1935 and not have the Abyssinian crisis or have a different Admiral responsible for carriers from 1931. That experience moved the RN thinking away from an Ark Royal style ship to an Illustrious style. The latter's design was completed in 1936 with the first 4 ordered by July 1937 (I.e. immediately it was possible after expiry of the 1922 Washington Treaty) and all laid down before the end of the year.

How far back are we turning the clock in this alternative history scenario?

 

[Shortround6]

How far back are we turning the clock in this alternative history scenario?

We could have more than one scenario, but UK vs Japan gets a little strange (more butterflies) the further back you go.
Not the least is the politics. Like how much or how little European/African war there is.
Italy says out of Abyssinian and spends more money on their military/Navy?
Which forces France to spend more money on it's navy, which means more French navy to send to Indo-China when Japan gets more uppity?
Dutch aren't going to much more than they did, Naval wise, even if they build the projected battlecruisers they won't show up until 1943-44 and that is if Germany never signs the treaty with Japan.
Edit> The Dutch had 2 cruisers on the stocks in 1940, completed after the war, 4 Destroyers on the stocks. 1 escaped to England, one broken up on the slip, one completed by the Germans and the last was launched by the Germans but scrapped. 8 Subs either completing or building <
For Japan to enlarge the war in China against new opponents from 1937 (or about then?) they need to think that the Europeans are going to be too busy somewhere else to respond effectively. For Japan to try to take on the British, French and Dutch by themselves (leaving the US out of it) is NOT going to go well for Japan if Germany and Italy sit back lunch while spectating. Japan NEEDS Germany to take over Czechoslovakia and for Italy to be stirring things up in Africa to the keep British, French and Dutch focused on Europe.

A lot of butterflies.

 

[Wild_Bill_Kelso]

I think we have to assume that there is an impetus for the UK/Commonwealth to go on a war footing as far as preparing for war in the Far East. We are assuming that the UK still has its intelligence network, and the intent to complete Singapore as a forward naval base/stronghold. The Admiralty would understand the problems involved re the extreme range to the theater.

As such I think the question is not whether they would gear up for war at the same rate, but what would change as far as allocating resources for the Far East war as opposed to what was done historically for the ETO/MTO.

One example that I think would apply involves the number of small[ish] escorts built for the war in the Atlantic. Would it make sense to build anywhere near the same number of Flower class corvettes? What would the chosen escort design be for the Far East? Japan did not plan on fighting using unrestricted submarine warfare, but how much would the Admiralty have incorporated that information in their plans?

Another example is the Fairmile B ML. They were not war winners, but they served a useful purpose in coastal waters and as inner zone escort ASW & gunboats, and they were designed to be deployable under their own power (with use of sail if necessary) to the farthest reaches of the Empire - bringing their own spares with them.

Still another small example is the Bombay bomber/transport. Its Air Ministry Specification specifically called for the ability to transport small numbers of Sqn personnel and spares (including a spare engine) over long distance for deployment/reinforcing purposes. They even had preset packages designed for transport, for the minimal level airfield construction necessary.

What about flying boats? The Sunderland was a good aircraft, but was it what they would have built if they were planning on going to war in the Far East? (I am not saying it was not appropriate, just that it might not have been the best they could have built for the Far East.)

A bigger issue (perhaps) that has been discussed elsewhere in the forum and on many other forums, is what would be the form of the new build carriers - improved Ark Royals, same or similar to the Illustrious class, or something significantly different?

And the destroyer flotillas. After a point in time, would they have continued to build the shorter range hulls of the G/H and J classes, or would they have switched to a longer range hull similar to the Tribal and L/M classes?

etc.

Let's keep in mind, it's not as if the RN didn't fight in the Far East. They most certainly did. The only 'what-if' aspect of this was if they did not have the active and direct support of the US Navy. Clearly they were expecting a lot of support from the USN in the real world, and they got it.

It's interesting to speculate as to what new things, or new variants of things may have been created. Some of that may be necessary to imagine a plausible scenario - maybe they get rid of the Blackburn Rocs after some minor incidents or skirmishes in Europe. I'll concede that one. It's safe bet the Bombays are going to be shot down pretty quick too so you won't have to worry about those too long, and those little escort ships will be sunk too if operating in the Pacific, so they'll have to commit their better ships (and aircraft carriers) to protect commerce around India and any Pacific islands they can hold on to.

One other consideration is typhoons. Those little escort ships will need to be well out of the way when something like this arrives inconveniently. I think the Brits were pretty good at meteorology? And they had been in India and places for centuries, 150 years in Hong Kong and Singapore. But I'm not sure how familiar they were with operating out at sea amidst cyclones. The US Navy was based in places like Pensacola and Norfolk where these are a fact of life. Pensacola gets hit or near miss from a hurricane every 2-3 years or so.

Finally logistics. Things like getting bulldozers and fuel, steel mesh landing strips etc. to the remote islands. Does the RN have that kind of capacity? How many marines did they have?

 

[Wild_Bill_Kelso]

This is what makes it very hard to compare the Japanese boats head to head with anybody else's boats.
View attachment 733211
The British built this thing in 1921-25 but the engines were unreliable and it was laid up in 1933 and scrapped in 1937.
four 5.2in guns.

That is really cool looking boat. Too bad about the engine trouble. It has a really neat art-deco / flash Gordon vibe to it. Would have been interesting to see if it could pop up in the midst of a (relatively light) enemy fleet and start blasting. I would imagine you'd want fairly high speed for egress though in such a scenario, and a really fast dive. Neither of which might be easy to do with something like that...

 

[Wild_Bill_Kelso]

For Japan to enlarge the war in China against new opponents from 1937 (or about then?) they need to think that the Europeans are going to be too busy somewhere else to respond effectively.

I don't think that is true. The Japanese war in Manchuria and then China (and for a minute, Russia) was taking on a life of it's own, as in, they were a small dangerous predator with jaws locked onto a very large prey animal, and were finding it impossible to extricate themselves. Dan Carlin's podcast on this is very useful I think in understanding the situation.

For Japan to try to take on the British, French and Dutch by themselves (leaving the US out of it) is NOT going to go well for Japan if Germany and Italy sit back lunch while spectating. Japan NEEDS Germany to take over Czechoslovakia and for Italy to be stirring things up in Africa to the keep British, French and Dutch focused on Europe.

A lot of butterflies.

Here I definitely disagree. You can combine most of RN, and everything the French and Dutch want to send to the Pacific and I think the Japanese can handle it. Japanese Army can conquer Indochina from the French. We saw how brutally Japan took Singapore and Hong Kong and crushed British forces in Malaya and Dutch in Java even with considerable American help. Not to mention crippling the Americans in Hawaii and swiftly taking Philippines.

As far as I'm concerned, please feel free to add all the Koolhaven and Fokker aircraft, MS 406s and Potez 630s and all the French and Dutch ships you want. France has some good kit which could come into play after 1940 but the divisions in French society would have, IMO, prevented them from deploying effectively in the Far East and they certainly would have been keeping most of what they had close to home to protect from trouble via Germany and Italy.

 

[Wild_Bill_Kelso]

Without war in Europe you would see a continuation of Black Swan production at low levels. It was the culmination of 10 years of sloop development. Well armed against both air and submarine attack and with more range than the faster Hunt class with similar armament. They were more complex to build and were a product of the smaller naval yards. But despite everything else they continued to be built throughout the war. And most importantly proved capable of taking a much heavier AA battery and radar equipment as time went on. At one point there was a trade off between these and a small batch of Hunts.

That is a nice looking little ship

HMS Black Swan (L57) - Wikipedia

en.wikipedia.org

Seems to compare pretty well to the (later vintage) US ones. Destroyer escorts are interesting little ships.

Evarts-class destroyer escort - Wikipedia

en.wikipedia.org

Buckley-class destroyer escort - Wikipedia

en.wikipedia.org

Cannon-class destroyer escort - Wikipedia

en.wikipedia.org

Rudderow-class destroyer escort - Wikipedia

en.wikipedia.org

This one, deployed in 1944, seems to be one of the most effective US types. 24 knots and heavily armed (apparently 28 knots in an extreme emergency) One of these (Samuel B. Roberts) was used in the Battle off Samar, it managed to close to very short range, doge 8" shells, and blew off the stern of the IJN heavy cruiser Chokai with a torpedo and set the bridge of the Chikuma on fire and blew up one of it's gun-turrets, before being sunk by three 14" shells from Kongo. Also another one of these rode out Typhoon Cobra and rescued 55 sailors during the storm, which is a good sign of seaworthiness.

John C. Butler-class destroyer escort - Wikipedia

en.wikipedia.org

 

[Shortround6]

Going to the British/commonwealth Cruisers and again starting with the oldest first and someone mentioned the Adelaide

the tail end of a series of ships dating back to 1909-1910 (?) or before design wise,
25 kts when new, 5560 tons
8 X 6in guns, 3 X 4in AA guns, 2 x 21 tubes removed in 1938-39 refit. An assortment of .303 AA guns?
She spent WW II on convoy duty mostly, she was too slow to join the newer (1918-1920) ships.

The "C" class ships. 15 Ships in Service in 1939. 2 sunk in 1940, 1 sunk in 1941,
kind of lumping them together here. There were 7 sub-classes but only 3 classes made it to WW II, the Caledon, Ceres and Carlisle-class ships that survived WW I made it to WW II and the older ships were scrapped along the way.
1917-1922 (peace time work slowed down) About 4200 tons 29 kts
5 X 6in guns, 2 X 3in AA, 2 X 2pdr AA, 8 X 21in tubes.

2nd gun behind the bridge.

Later ones had the 2nd gun mounted superfiring over A gun and the last ones built got the raised trawler bow for better sea keeping.
A number of them were converted to AA Cruisers as has been noted by others.
Here is a interesting note. A lot has been made about the Japanese interest in naval aviation. Yet the normal Japanese ships of the 1920s and 30s had much less space/tonnage devoted to AA guns than the British, who weren't doing that much anyway so the Japanese were really behind the curve. The AA cruisers were fleet escorts, to raise the number of Aa guns defending the fleet, or group.

The "D"s... 8 Ships
"C"s with 20 ft added to squeeze another gun in.
1918-1922 (peace time work slowed down) About 4850 tons 29 kts
6 X 6in guns, 2 X 3in AA, 2 X 2pdr AA, 12 X 21in tubes.

1/2 with flat bow and 1/2 with trawler bow. torpedoes are triple mounts.

"E" class 2 ships
laid down 1918, completed 1926, 7580 tons 33 kts
7 X 6in guns, 3 X 4in AA, 2 X 2pdr AA, 9 smaller(?) 16 X 21in tubes.

only 6 guns to the Broadside, but 16 torpedo tubes.
A few notes on speed/propulsion. These ships were about 100ft longer than the "D"s, mostly to fit in increase from 40,000shp to 80,000shp needed for the 33 kt speed.
They needed 4 shafts instead of 2 shafts. Not all navies used the same standards of durability and reliability when designing their powerplants and the RN was rather conservative in general. However this meant RN ships rarely (very rarely) broke down on distant stations or during long periods of service. destroyers in all navies require more maintenance than larger ships (fast cruisers that tried to use DD machinery were somewhat more problematic)
The 2 "E"s had more room for extra AA guns later and had enough full for a lot more range than the "D"s.

The Hawkins class 4 ships
1916-1925 (peace time work slowed down) About 9850 tons 30-31 kts
7 X 7.5 in guns, 3 X 4in AA, 2 X 2pdr AA, 6 X 21in tubes. check ships for modifications.

The Effingham pictured had been converted to 9 X 6in guns and a beefed up AA battery, she was lost off Norway (ran aground).
There were 5 ships The Raleigh ran aground in 1922 an was scrapped. this is probably the most modified, screwed around with class of ships anywhere.
Different numbers/types of boilers some with coal and some all oil and then later changes, the Vindictive was converted to an aircraft carrier in 1917-18 and converted back to a cruiser in 1923 and so on......and on..............and on.
These were the ships that were cause of the whole 8in gun section of the Washington treaty. They were also the ships that inspired the Japanese Furutaka class as orgialy built with 6 single gun turrets.
They were supposed to scrapped in the late 30s for new construction by treaty but the time came the treaties were pretty much kaput and a couple of them had been 'saved' as training ships/laid up disarmed were put back into service.
As front line cruisers they were not really worth much. While the RN had fitted power traverse and elevation some time after completion (hand cranking a 46 ton mount was not a good idea) the real problem was ammo supply. Without a powered hoist at the mount/s rate of fire was going to slow to crawl. The Projectile weighed 200lbs and moving them by hand (and sometimes up a deck) does not make for a good picture in a close range night action.
They might have been hell on an armed merchant cruiser.

The later cruisers in later posts.

 

[Thumpalumpacus]

It was the same 6"/50 gun that was used in all the cruiser classes from the Leanders to the Minotaur/Swiftsure completed 1944/45. Only the nature of the turrets changed. Twin Mk.XXI (Leander/Arethusa) and triple Mk.XXII (Town class first 8 ships) had a "short trunk" turret. Charges and shells were moved from magazines to handling rooms beneath the turret, and then on other hoists into the turret. The Mk.XXIII "long trunk" turret was fitted in later classes (Town class last two ships / Edinburgh group, Fiji / Crown Colony & Minotaur / Swiftsure). In this turret the charges and shells were hoisted from magazines direct into the turrets with a manpower saving. I don't think there was much difference in rate of fire per barrel between turret types.

The theory behind all the nations cruisers armed with triple 6" guns from the early 1930s was that sheer weight of fire from 12/15 6" barrels would overwhelm an enemy (more hits each casing less damage) whereas the heavier 8" shells would result in fewer hits each causing more damage. But the need for such ships came out of the London Naval Treaty 1930. It split cruisers into two categories:-

1. Cruisers with guns greater than 6.1"
2. Cruisers with guns not greater than 6.1"

The first group was limited both by total tonnage AND by the number of ships permitted. So USN/RN/IJN was 18/15/12, and both the RN and IJN had already built to these limits (the RN actually needed to convert/disarm/scrap the Hawkins class by the end of 1936 to comply). The US got more ships in this category by special pleading.

The second group had an overall tonnage cap only. So you could have a lot of smaller cruisers or a lesser number of larger ships.

The RN thought that this would limit cruiser size to around the size of a Leander. In fact it didn't because the Japanese built the Mogami class with 15x6.1" forcing a new cruiser race of 9,000-10,000 ton ships armed with a generally larger number of guns than previously. But for the RN the issue was numbers so they limited the Towns to 12 guns. The Edinburgh sub group were initially planned to have 16x6" in 4 quad turrets. The US built the Brooklyn class in response.

That was why the 1936 London Treaty sought to limit ship size rather than total tonnage to help the RN with its need for numbers.

The Mogami class were designed from the outset to be upgradeable to 8", which is what happened after the Japanese quit the Treaty system.

Article XVI 1. The completed tonnage in the cruiser, destroyer and submarine categories which is not to be exceeded on 31 December 1936 is given in the following table:​
Maximum quantity of cruisers, destroyers and submarines allowed to each nation	Categories​ United States​ British Commonwealth of Nations​ Japan​ Cruisers: ​ ​ ​ 180,000 tons (182,880 metric tons)​ 146,800 tons (149,149 metric tons)​ 108,400 tons (110,134 metric tons)​ 143,500 tons (145,796 metric tons)​ 192,200 tons (195,275 metric tons)​ 100,450 tons (102,057 metric tons)​ Destroyers 150,000 tons (152,400 metric tons)​ 150,000 tons (152,400 metric tons)​ 105,500 tons (107,188 metric tons)​ Submarines 52,700 tons (53,543 metric tons)​ 52,700 tons (53,543 metric tons)​ 52,700 tons (53,543 metric tons)​
Details of how the tonnage is assigned	2. Vessels which cause the total tonnage in any category to exceed the figures given in the foregoing table shall be disposed of gradually during the period ending on 31 December 1936. 3. The maximum number of cruisers of sub-category (a) shall be as follows: for the United States, eighteen; for the British Commonwealth of Nations, fifteen; for Japan, twelve. 4. In the destroyer category not more than sixteen percent of the allowed total tonnage shall be employed in vessels of over 1,500 tons (1,524 metric tons) standard displacement. Destroyers completed or under construction on 1 April 1930 in excess of this percentage may be retained, but no other destroyers exceeding 1,500 tons (1,524 metric tons) standard displacement shall be constructed or acquired until a reduction to such sixteen percent has been effected. 5. Not more than twenty-five percent of the allowed total tonnage in the cruiser category may be fitted with a landing-on platform or deck for aircraft. 6. It is understood that the submarines referred to in paragraphs 2 and 3 of Article 7 will be counted as part of the total submarine tonnage of the High Contracting Party concerned. 7. The tonnage of any vessels retained under Article 13 or disposed of in accordance with Annex II to Part II of the present Treaty shall not be included in the tonnage subject to limitation.​

Right, I was aware of the reasoning and Treaty stipulations for the two types of cruisers, I just wasn't clear if the latest British CLs had the high rate of fire of the American Brooklyns. Thanks for the info!

 

[Shortround6]

As far as I'm concerned, please feel free to add all the Koolhaven and Fokker aircraft, MS 406s and Potez 630s and all the French and Dutch ships you want. France has some good kit which could come into play after 1940 but the divisions in French society would have, IMO, prevented them from deploying effectively in the Far East and they certainly would have been keeping most of what they had close to home to protect from trouble via Germany and Italy.

perhaps the French and Dutch would have been little more than speed bumps but the whole Japanese attack of Dec 1941-March of 1942 of hanging by shoe strings, frayed knotted shoe strings at that. A couple of weeks of delay might have broken one or more of the shoe strings.
Ki-43 Production in 1941 was 157 aircraft, 43 of them in Dec, they built another 113 in the first 3 months of 1942.
Zero Production totaled 507 by the end of 1941, the first 100 or so were being used as trainers (they had a few limitations) and they built another 152 in the first 3 month of 1942.
If the Japanese do NOT start in French Indo china and have to take it over? Yes they can do it, but how much longer to take Malaya and Singapore? A few weeks? a month?
If the British had more equipment to give the Indian troops in Malaya? To heck with more troops, just give them 1/4 to 1/3 of the artillery and anti-tank and AA guns that an equivalent number of of Troops in NA had. The troops in Malaya were lacking just about all heavy weapons.
Lets Remember that the Japanese have said that if the British did not surrender at Singapore when they did the Japanese would have had to surrender or face starvation in just another few weeks.

A few more Dutch destroyers (3?) and submarines (Dutch were building 8 in 1939-40, 3 escaped to England) ?

Japanese win the naval battles but loose more transports during the invasions of the DEI.
How long do the land battles last?

Can the Japanese afford to loose either the time needed or the planes and troops needed to overcome the French/Dutch defenses?

They can/will win but what happens to the time table/s?

Maybe with more carriers supporting the DEI invasions (not attacking Pearl) the Dutch planes are wiped out in the first two days, who knows?

 

[mack8]

perhaps the French and Dutch would have been little more than speed bumps but the whole Japanese attack of Dec 1941-March of 1942 of hanging by shoe strings, frayed knotted shoe strings at that. A couple of weeks of delay might have broken one or more of the shoe strings.
Ki-43 Production in 1941 was 157 aircraft, 43 of them in Dec, they built another 113 in the first 3 months of 1942.
Zero Production totaled 507 by the end of 1941, the first 100 or so were being used as trainers (they had a few limitations) and they built another 152 in the first 3 month of 1942.
If the Japanese do NOT start in French Indo china and have to take it over? Yes they can do it, but how much longer to take Malaya and Singapore? A few weeks? a month?
If the British had more equipment to give the Indian troops in Malaya? To heck with more troops, just give them 1/4 to 1/3 of the artillery and anti-tank and AA guns that an equivalent number of of Troops in NA had. The troops in Malaya were lacking just about all heavy weapons.
Lets Remember that the Japanese have said that if the British did not surrender at Singapore when they did the Japanese would have had to surrender or face starvation in just another few weeks.

A few more Dutch destroyers (3?) and submarines (Dutch were building 8 in 1939-40, 3 escaped to England) ?

Japanese win the naval battles but loose more transports during the invasions of the DEI.
How long do the land battles last?

Can the Japanese afford to loose either the time needed or the planes and troops needed to overcome the French/Dutch defenses?

They can/will win but what happens to the time table/s?

Maybe with more carriers supporting the DEI invasions (not attacking Pearl) the Dutch planes are wiped out in the first two days, who knows?

Also, one can assume that most of the troops, shipping and planes OTL aimed at the Phillipines (and places like Guam and Wake) will in this ATL be aimed at the british/french/dutch etc.

Right, I was aware of the reasoning and Treaty stipulations for the two types of cruisers, I just wasn't clear if the latest British CLs had the high rate of fire of the American Brooklyns. Thanks for the info!

NAVWEAPS said the rate of fire of the british gun was 6-8 rpm. The japanese 15,5cm could do 5-6 (theoretical max of 7 but this could not be reached due to hoists design etc - on the other hand it was excellent in the antiship role), the US 6 inch could do 8-10 rpm.

 

[Shortround6]

Right, I was aware of the reasoning and Treaty stipulations for the two types of cruisers, I just wasn't clear if the latest British CLs had the high rate of fire of the American Brooklyns. Thanks for the info!

Some of it depends on the range but the British cruisers look like they had about 75% of the fire rate of the Americans, which is not bad compared to 8in guns
US guns had power ramming up to 20 degrees and the British used had ramming, since everybody had to lower the guns to load/ram elevation/range had an influence on rate of fire.

Japanese 5.5s depended on how far the crews had to lug the shells.
Agano may have been at 5-6 rpm and the Oyodo was lucky to hit 5 rpm.

 

[mack8]

Getting back a bit to the potential UK shipbuilding program if no war in Europe (at least not with UK involved in it yet), do i understand correctly that if not for the war they would have probably continued to build 1-2 CV, 2 BBs, 7 cruisers and 2-3 DD flotillas in both 1940 and 1941? As i understand they wanted at least another pair of Implacables in 1940 but this was not done due to the war situation. Also, when was Vanguard supposed to be laid down if not for the war situation, perhaps 1940? Do you think they have the capacity to lay down all 6 Lions by 1942, or they would have to pare down the number anyway (maybe 4 plus Vanguard?).

Regarding carriers, apart from the 8 armoured ones, iirc at some point they wanted 6 smaller "trade protection" carriers, presumably something akin to Unicorn or the later Colossus CVL? Don't know if they will start building some of these in 1940 or 1941, would be interesting what more informed folks know on the subject.

As a sidenote, without the war in Europe, many of the lessons RN (with significant impact in ship design) and UK as a whole learned the (very) hard way would not have been learned yet when going against Japan in this ATL. So at first i think many of those lessons will be learned the hard way against the japanese. I would not be surprised in the least if a lot of equipment sent in FE initially would still be second rate even if there is no war in Europe, since the british and western powers in general were looking down on the japanese.

 

[Shortround6]

Since it takes about 3-4 years (minimum) to build large carriers or BBs anything laid down in 1939-40 won't show up until several years in.
Large Cruisers are about 1 year quicker.

the last point is sort of why I favor the Germany stumbles just a bit and Italy gets taken out (or at least gets kicked out of NA with significant naval losses) scenario.
The British have time to many of the lessons from 1939-40 and bit if time to shift things to the Far East.

Granted some officers didn't draw some of the right lessons from that experience.