Rn vs IJN

[Shortround6]

trying to get the Navy stuff off the Japanese Aircraft were late thread.

Yeah sure, any kind of explosive ordinance was dangerous to carry when under fire. US and RN and German ships carried torpedoes too.

The Japanese torpedoes were particularly hazardous. The oxygen could intensify fires if it leaked from fragments.

With the Japanese advantages in detection, they could spot enemy (including RN) ships early and engage them from beyond the maximum range of the British vessels (guns or torpedoes)

This assumes perfect weather, which it often wasn't.

It also assumes good height above water for the lookouts and while smoke could sometimes be spotted over the horizon (in day light) that depends on haze, fog, squalls and so on. The Japanese did have an advantage in visual detection. But it was by no means universal or even ling ranged at times.
Of course the effectiveness of British Radar in 1941-42 was not anything to close to 100% either.
And there was a difference between search radar and gunnery radar. Pages worth.

 

[RCAFson]

The other thing is that the RN suffered massive attrition from Sept to 6 Dec 1941 from combat in the ETO/MTO. So we have to take this into account when looking at a pure RN-IJN war.

6 Dec 1941
Relative technology and training
__________________RN__USN__IJN
AW radar__________Y___Y____N
SW radar__________Y___N____N
SW 10cm radar_____Y___N____N
FC AA radar_______Y___N____N
FC surface radar__Y___N____N
carrier radar GCI_Y___L*___N
ASV radar_________Y___N____N


Intensive Night action training
___________________Y____N____Y
Flashless powder___Y____N____Y
Reliable Torpedo___Y____N____Y
VL range Torp._____N____N____Y

Naval losses (including /R under repair exceeding 6 months prior and at 6 Dec 1941) from Sept 1939 to 6 Dec 1941.

CV________________3/2R__0____0
BB________________3/1R__0____0
Cruisers______10/15R____0____0
DD___________51/~30R____1/1R_0
Subs__________33/3R_____0____0

The RN had lost 3 fleet carriers, 3 battleships, 23 cruisers, 83 destroyers and 33 submarines up to 6 Dec 1941 including tens of thousands of fatal casualties amongst long service regulars many of whom had vital skills . Also, numerous ships were laid up being repaired. The FAA was constantly being drained of aircrew and aircraft and couldn't expand nearly as rapidly as planned. With no European war the RN would be about 50% larger than historically, on 6 Dec 1941.

Edit - I previously read some dates incorrectly and have revised the loss figures accordingly
data:

HM Ships Damaged or Sunk by Enemy Action in World War II | Royal Australian Navy

Royal Australian Navy

www.navy.gov.au

I'll add this link here as well:

The Evolution of the U.S. Navy into an Effective Night-Fighting Force During the Solomon Islands Campaign, 1942 - 1943

https://etd.ohiolink.edu/apexprod/rws_etd/send_file/send?accession=ohiou1214239278&disposition=inline

 

[SaparotRob]

Warspite rules! Yamato drools!

 

[Greg Boeser]

Warspite rules! Yamato drools!

Easy there, fella. It's only Thursday night.

 

[Shortround6]

The Drachinifel youtube channel has got a couple of two week old videos about the US and IJN night fighting which goes into some of the factors in some depth. Howmuch can be applied to the British I don't know.

Weather around Guadalcanal was often rather lousy restricting visibility perhaps more that in some other areas of the Pacific or Indian oceans?
Getting radar to work in-between the Islands was often a problem (echoes from the land masses)

Early radars used a different display, the PPI display didn't show up until the 2nd or 3rd generation equipment (depends on type of equipment) and didn't give the overhead view that most of us think of with all the surrounding ships laid out around the radar ship's position in easy to see location.

the first radars used either the type A display or the type B or used two screens to display the range on type A and the azimuth on a different screen (?)

Multiple targets show up on the type A display as multiple peaks if close together.

The US was doing "some" training prewar. But the US was working on a different doctrine. The Japanese were going to try to approach using stealth, spot the targets and fire torpedoes, Wait for hits (or time the runs) open fire briefly and then run away. Much like the most navies had done in WW I.
The US was planning on using their guns to shoot through the enemy screening forces to reach the battlefleet.
Both sides were going to use heavy cruisers (and light) to make holes in the oppositions escort screen to get the Destroyers into firing range. The doctrine on both sides evolved over much of the 1930s. At the Battle of Balikpapan The US used the old style of attack, in large part because they were using the old 4 stack destroyers with much weaker gun power and the old MK 8 torpedoes.

 

[Just Schmidt]

Diving into this discussion may be compared to making a surprize attack on the US fleet at Pearl Harbour, in that it afterwards appears as something that should have been avoided.

Now for the IJN vs RN. i'd say that both were able to win battles against each other, but which one was best? ironically my very generalized assessment is that the IJN in many ways have MORE punch for a given category of ships, so not parallelling the relative lack of punch in their aircraft. This at the cost of higher vulnerability, the torpedoes are an exellent example. As an offensive weapon they beat all other torpedoes of the area hands down, but it does come at a greater risk. The Japanese heavy cruisers also had an impressive primary armament, but maybe not too much staying power in a prolonged engagement. In as far as this was a conscious choice, it does make a kind of sense. If you are outnumbered 3 to 5, exchanging punches all day looks like a questionable strategy. better try to get in a telling blow early on.

Here is an important point. japan did not have the industrial base of the UK, and by treaty is was restricted to the ratio 3 to 5. Everything else being equal, technologically the UK should be ahead in more areas than the Japanese. Nothing to do with racial superiority, but simply the crushing effect of numbers. And more so when the ratio is invoked, even if not everything may have been built up to treaty limits.

But OK, the IJN vs RN. As SR observed another place, luck plays a part, as capital ships were not employed in the tens of thousands. So what does the battles around Guadalcanal really tell us?

And what are we comparing? Is it the entire navies in splendid isolation, or is it the historical setting where simply the US is removed from the equation? That one I think the IJN would win 'easily', as UK still would need to contain the Italian and german navies, and were fighting half a world away from home. And in geopolitics, are we counting in the Commonwealth?

Yes, the IJN can sink the whole RN by torpedoes from a distanse of 15 kilometrs, providing the RN ships do not move or change course. Sure the first hits will be a surprize, but the RN will catch on to the capabilties of Japanese torpedoes.

In a mutual agreement to do a desisive batlle like Jutland the UK battleline should maul the IJN, if everything is included. But adding carriers makes it interesting. While british CAP was without equal early on, it should be swamped by by the Japanese carrier forces. (Which themselves may be swamped by the sheer number of targets available). They should be, considering the different geo-strategic considerations going into the respective outfits of carriers.

But where is this hypothetical Kentai kessen taking place? and why does both nations agree to risk their whole fleets in one engagement? With the US out, why are they even fighting each other? here is my main problem. The RN cannot invade japan, and the IJN cannot invade great britain. Can they starve each other out? I doubt it. So to account for regional geography, strategic goals, strategy and tactics chosen, the role of the RAF and IJAAF depending on which side of the globe the battle is taking place. Or the battles making up a campaign?

Ultimately we cannot come close to a realistic result without taking the context into account, and removing the US removes the context, and makes it very hard to supply a new realistic one.

So having made this infamous attempt to blow the discussion out of the water before it is even properly started, I will immidiately apologize and sue for peace. It's not as if i am going to stop you. Neither is it my hope, I'm sure this will prove interesting.

As long as it is remembered that it is not taking place in the real world. I'll just sulk in the background.

 

[EwenS]

In Britain PPI displays were first proposed in 1938 and development began in Dec 1939. The first use was in RAF GCI radar stations from Oct 1940. Initially it couldn't be used with RN air warning sets like Type 279/281 because their radar beams were much wider than the RAF GCI sets. Then, around mid-1942, Illustrious scrounged an RAF PPI display while in Ceylon for use with her Type 281 set. It allowed a "fair interpretation" to be made.

The first official RN PPI went to sea in the Battleship KGV in March 1942 to work with her Type 273 centimetric surface warning set. Fitted with a 12" screen it was "about twice the size of an office desk"! It was not reliable or effective and was little used. A 9" model was then trialled in Aug 1942 and a contract placed with EMI for development of a Naval version. That was first tested in April 1943 with pre-production sets available from Aug. DoY had one of these by the Battle of North Cape in Dec, fitted to her Type 273Q set.

The disadvantage of the PPI initially was that it was part of the radar cabinets and therefore remote from Fighter Direction Officers, bridge personnel etc, and needed to be operated in a darkened compartment. It was 1943 before these problems were overcome.

One development was the Skiatron display to "simplify the immediate and direct plotting of radar targets and of tracks and vectors, without the room having to be darkened. Echoes in PPI form, from a special CRT, were projected optically upwards onto a translucent circular ground-glass screen, and appeared as dark shadows (or 'stains') on a light background. The ground-glass screen was engraved with a circular 'spider's web' of some 24in diameter (as against the normal British Naval PPI's diameter of 9in) and could be used as a plotting surface using a wax pencil, for plotting tracks of aircraft either from actual radar echoes or by dead reckoning." First trials in Indomitable in March 1943 following her post Pedestal repairs and refit. Howse.

Remote PPI (on bridge for example) for British radars began with Type 276 which began to be fitted as a successor to Type 271/272 in smaller ships from early 1944.

US PPI screens entered service earlier. US built Ruler class escort carriers delivered from July 1943 had PPI screens for their air search radar sets and were eyed enviously by others in the Fleet. They were also present on the SA air search and the SL centimetric surface search sets fitted to the Captain & Colony class frigates.

 

[Shortround6]

Thank you.

It would seem that any radar is better than no radar but the impression that many of us have of 1944 radar is a far cry from 1941-42 radar as far a situational awareness goes.
Or CIC's fitted to really help keep track of large surface battles in addition to air battles.

It appears that the US was doing some night training or at least using night training/problems in their "fleet battles" but I don't know how often they did it, Annually, semi-annually or rather frequent? US doctrine with the 5"/38 was different than many other navies for night combat use. It may not have been realistic/effective but it was different.

We also have to look at the RN's doctrine, battle plans, training and equipment.

The RN had wanted 70 cruisers in the early 30's. They didn't get them due to treaties and lack of money. I believe that was just to counter the Japanese and provide for whatever else may have been going on. In the early 30's Germany was not a real threat, so that the British were looking at numbers to counter Japan with Japan timing the out break of war to have the most ships ready for combat and the RN having the normal number undergoing refit/repair and using some cruisers for trade protection even in the Atlantic while fighting the Japanese.

German and Italian building programs changed the desired numbers as they also became more belligerent.

Japanese (and many others) used search lights at times and the use of star shells was wide spread. Some navies (including the RN) sometimes fitted dedicated star shell guns.

 

[Thumpalumpacus]

Ultimately we cannot come close to a realistic result without taking the context into account, and removing the US removes the context, and makes it very hard to supply a new realistic one.

Japan bypasses the Philippines while still invading Malaya, Burma, capturing Singapore, and threatening Australia. There, problem solved.

 

[EwenS]

The RN had wanted 70 cruisers in the early 30's. They didn't get them due to treaties and lack of money. I believe that was just to counter the Japanese and provide for whatever else may have been going on. In the early 30's Germany was not a real threat, so that the British were looking at numbers to counter Japan with Japan timing the out break of war to have the most ships ready for combat and the RN having the normal number undergoing refit/repair and using some cruisers for trade protection even in the Atlantic while fighting the Japanese.

German and Italian building programs changed the desired numbers as they also became more belligerent.

Japanese (and many others) used search lights at times and the use of star shells was wide spread. Some navies (including the RN) sometimes fitted dedicated star shell guns.

The 70 cruiser requirement can be traced back to 1924 but Friedman notes "Unfortunately no credible explanation has survived, but at times it was stated that twenty-five were for the fleet and forty-five to protect trade". He then deduces from various documents, statements etc that it would look something like this:-

Fleet - 2 squadrons (10 ships) for the scouting line & 2 squadrons (10 ships) to work with the destroyers + 25% margin for refits = 25
Trade protection in various areas:-
China - 2 squadrons
+ single squadrons on the following stations
Australia
New Zealand
Indian Ocean
North Atlantic
South Atlantic
Total - 7 squadrons with 35 ships + 25% margin + flagship for Australia / New Zealand = 45

The China squadrons would have been to hold the fort until the arrival of the Fleet from Britain. Note this was based around 5 ship squadrons but later 4 was the norm. So it is a bit of a moveable feast. And this is not just the RN but also the Dominion navies.

There seems to have been a reluctance by the Admiralty in the 1920s to expressly state that Japan was the "enemy" lest the politicians not see it that way and use it as an excuse to cut the Fleet. And in the mid-1920s Germany & Italy present no credible threat.

By 1935, with escalating threats elsewhere 70 was accepted by the Government as the minimum acceptable especially since the USA could not be depended to help against Japan. So the outcome of the 1936 London Treaty was a lifting of the quantitative limits on cruiser tonnage and the imposition of a qualitative limit of 8,000 tons. That helped Britain in the search for numbers. From 1936-38 the RN had been ordering 7 cruisers per year with another 4 in 1939.

But in 1937 the RN prepared a document outlining a "New Standard Navy" which set the cruiser requirement at 100 which was to be achieved by 1944. This was nver formally adopted but many of the orders placed match it fairly closely.

On 3 Sept 1939 the British & Commonwealth cruiser fleet looked like this:-

1 WW1 Town class -HMAS Adelaide
13 C class - 6 coverted to or under conversion to AA cruisers (plans for another 4 conversions were cancelled on outbreak of WW2. Intended for convoy protection)
8 D class - (plans for conversion to AA ships cancelled on outbreak of WW2. intended for convoy protection)
2 E class
1 modernised Hawkins - Effingham
2 Hawkins - rearmed on outbreak of WW2. (these had been disarmed around 1936 to comply with the 1930 London Treaty)
7 Kent - 2 RAN manned
4 London
2 Norfolk
York & Exeter
5 Leander - 2 New Zealand manned
4 Arethusa
3 modified Leander - all with the RAN
10 Town class
Total 64 ships.

Under construction or on order with construction about to begin:-
10 Dido
11 Fiji

Then on 4 Sept 1939 plans made immediately pre-war were put into effect. It was decided to complete 2 of the Didos with 4.5" guns intended for the D class conversions in order to obtain them sooner. Another 6 Dido (4 agreed pre-war + 2 to use the 5.25" turrets on order for the 2 ships switched to 4.5") and 2 Fiji (already planned but orders were brought forward) were ordered to utilise available building space. Then on 28 Sept 2 Fijis to be built in Royal Dockyards were cancelled to free up the manpower for conversion and repair work.

On 3 Sept 1939 a number of the older classes had only recently been reactivated following periods in Reserve. Dorsetshire, Kent, Cornwall & Birmingham were on the China station while Manchester, Liverpool & Gloucester were on the East Indies station.

No further cruisers were able to be ordered until 1941 due to changed priorities. Of these only Swiftsure saw combat while HMCS Ontario (ex Minotaur) was en route to the Pacific when the war ended.

 

[Just Schmidt]

Japan bypasses the Philippines while still invading Malaya, Burma, capturing Singapore, and threatening Australia. There, problem solved.

On the contrary.

If you can bypass the Philipines, then why not bypass the British holdings and go directly for the oil in Dutch East India? That's what you need for the main show in China. While an empire can never really get too much empire, Japan would probably have preferred to wait with trhe co-prosperity thing untill China was brought to heel. And why on earth would you threaten Australia?

And if the US is not putting an embargo on the oil, why not just buy it? Or do we 'just' assume that they bypass a hostile USA?

I'd love to playtest the IJN vs RN board game, but fitting it into history would be a nightmare.

 

[RCAFson]

On the contrary.

If you can bypass the Philipines, then why not bypass the British holdings and go directly for the oil in Dutch East India? That's what you need for the main show in China. While an empire can never really get too much empire, Japan would probably have preferred to wait with trhe co-prosperity thing untill China was brought to heel. And why on earth would you threaten Australia?

And if the US is not putting an embargo on the oil, why not just buy it? Or do we 'just' assume that they bypass a hostile USA?

I'd love to playtest the IJN vs RN board game, but fitting it into history would be a nightmare.

Japan attacked in Dec 1941 precisely because it seemed that the Axis was winning and the RN had suffered massive losses. So we have two possible scenarios here, one where the RN has been terribly bled and the British Empire and Commonwealth (BEC) is engaged in a life and death struggle in the ETO/MTO or one where the the BEC has not gone to war in the ETO/MTO and the RN has been free to expand as per it's prewar plans and the BEC could devote it's entire resources to fighting Japan.

If we look at the non-war BEC in Dec 1941 and compare it's scientific, economic and military resources with Japan, we can see that the odds are tilted heavily in favour of the BEC and it's very likely that Japan would not have attacked.

 

[EwenS]

RN planning in May 1939 for a war in the Far East in 1942, without a war against Germany & Italy, showed the following proposed dispositions (note that the cruiser figure is for those capable of carrying aircraft only):-

Home waters - 9 capital ships , 13 cruisers, Formidable, Illustrious, Victorious with Furious as the training carrier
Trincomalee - 5 cruisers, Courageous (in a trade protection role with 24 aircraft), Albatross
Singapore (Hong Kong in peace) - 12 capital ships , 15 cruisers, Ark Royal, Indomitable, Implacable, Indefatigable with Glorious (in a trade protection role with 24 aircraft)
Esquimalt, Canada - 3 cruisers
Kingston, Jamaica - Hermes
Simonstown, South Africa - 2 cruisers
New Zealand - 2 cruisers

Total - 21 capital ships, 40 cruisers, 11 carriers, 1 seaplane carrier

A few months later for a simultaneous war against Germany & Japan in March 1944 the capital ship distribution was expected to be
Home - 2x1939 Lion class, 5xKGV, 3xbattlecruiser
Singapore - 2x1938 Lion class, 2xNelrod, 5xQE, 3xR class
Total - 22

This to fight a supposed IJN in 1944 of 4xnew battleship, 2x new battlecruiser, 2xNagato, 2xFuso, 2xIse & 4xKomgo = 16 capital ships. They were not expecting the new battleship to be the size of Yamato.

 

[Wild_Bill_Kelso]

I can't really do this thread justice right now, which will require looking at all the kit and at least some of the tactics in detail.

And I appreciate the data being posted here. It's helpful.

But before this descends into debates about minutae, I think it's a good idea to do a brief 'high level' overview. These numbers are quickly googled so please correct rather than crucify if some are off.

This presumes no war in Europe and does not take into consideration losses to the Germans in the early war.

Air War
Japan has A5M, A6M2, D3A, B5N initially. Later A6M3, D4Y, B6N. Very late A6M5, B7N.
The larger Japanese carriers carried a lot of planes - 72 aircraft (Shokaku class), 64 (Hiryu class), 63 (Soryu class)
The Japanese had 13 fleet carriers during the war (according to quick google) plus 7 CVL and 10 Escort Carriers. 30 overall.
The Japanese also had the G3M and G4M which could sink ships at long distance

The Japanese also had quite good seaplanes (notably the H6K and superb H8K flying boats) and seaplane fighters (the deadly A6M2-N) which I think were a match for the Fulmar etc. The IJN had about a dozen seaplane tenders or 'seaplane carriers' of various types.

RN / FAA had Fulmar, Sea Gladiator, Sea Hurricane. Later Seafire. For strike planes Swordfish and Skua, and later Albacore and then Barracuda. If you include US planes then also Martlet and Tarpon.
RN fleet carriers carried around 40-50 planes - Courageous (48), Ark Royal (50), Illustrious (36), Formidable (40), Victorious (36), Indomitable (45), Implacable (1944 - 54), Indefagtiable (1944 - 54), Colossus Class (1944 - 48)
The British had 10 fleet carriers during the war (according to quick google.) with 52 carriers overall including CVL and Escort.
The British had Beaufighters and Beauforts, as well as the slow but very long ranged Wellingtons which could carry torpedoes and could sink ships at night

The British had the very good Sunderland flying boat.

The Japanese had much better fighters, significantly better range, and better strike aircraft. They also fielded more carrier aircraft per task force, generally.
The British had radar and the ability to perform strikes at night

One thing to look at in detail is how much AAA each side had. British had radar as part of their AAA defense.

In terms of damage control both the IJN and British had some problems. British had armored carrier decks but were vulnerable to torpedoes.
Overall the RN looks very vulnerable in any carrier conflict.

Surface War
IJN had more modern ships and the heaviest battleships of the war. Total 12 BB, 18 CA, 25 CL, 169 DD
RN had more ships overall (15 BB, 66 +35 CA, 184 + 277 DD)

Japanese had an advantage in optics and in particular night vision
British were ahead on radar.
IJN had much better and deadlier ship-launched torpedoes (with capabilities that the British were not aware of)

Based on the 'high level view' I'd put the edge for surface combat to the IJN for quality, especially in 1941 and 42, though the RN has the quantity, at least potentially and may come to parity in quality by the later war.

Submarine War
IJN has a lot of submarines and they are pretty good (started with 63, built 111, peaked at 174, lost 128)
British also had a lot (started with 60 and built 238, losing 79) and were also pretty good with good torpedoes from the start.

I think the British probably had an edge in ASW warfare. Certainly they had the Sunderland which was a very active and (I think) pretty effective ASW aircraft and a lot of experience dealing with submarines going back to WWI. I think the IJN was a bit late to the game in taking ASW seriously enough, though we should look at that in detail particular in terms of ship borne ASW.

I'm not sure about details like sonar on each side.

 

[RCAFson]

RN planning in May 1939 for a war in the Far East in 1942, without a war against Germany & Italy, showed the following proposed dispositions (note that the cruiser figure is for those capable of carrying aircraft only):-

Home waters - 9 capital ships , 13 cruisers, Formidable, Illustrious, Victorious with Furious as the training carrier
Trincomalee - 5 cruisers, Courageous (in a trade protection role with 24 aircraft), Albatross
Singapore (Hong Kong in peace) - 12 capital ships , 15 cruisers, Ark Royal, Indomitable, Implacable, Indefatigable with Glorious (in a trade protection role with 24 aircraft)
Esquimalt, Canada - 3 cruisers
Kingston, Jamaica - Hermes
Simonstown, South Africa - 2 cruisers
New Zealand - 2 cruisers

Total - 21 capital ships, 40 cruisers, 11 carriers, 1 seaplane carrier

A few months later for a simultaneous war against Germany & Japan in March 1944 the capital ship distribution was expected to be
Home - 2x1939 Lion class, 5xKGV, 3xbattlecruiser
Singapore - 2x1938 Lion class, 2xNelrod, 5xQE, 3xR class
Total - 22

This to fight a supposed IJN in 1944 of 4xnew battleship, 2x new battlecruiser, 2xNagato, 2xFuso, 2xIse & 4xKomgo = 16 capital ships. They were not expecting the new battleship to be the size of Yamato.

Of course we also have to add the Dutch and French naval strength as well, if the IJN is occupy and/or target those nations FE possessions.

Also the above allocations were based upon a neutral but potentially hostile Germany and Italy and USSR. A USSR that is not at war would present a very serious threat to Japan and would cause some serious anxiety in Japanese planning.

Really, if we go down the road of what ifs the possibilities are almost endless. The only scenario that can be looked at is a straight fight between Japan and the BEC, with all other planning constraints removed, except if Japan decides to trigger hostilities with Dutch and French forces.

 

[SaparotRob]

The RN had to be better at ASW if only through experience. I don't recall the IJN's ASW being anywhere near Allied capabilities. In the opening days of the American Japanese PTO, it was who found whom first. If the Philippines are still in American hands, that's a listening station for the RN. If the USN isn't involved, then the fleet actions, I'm assuming, are closer to more coasts, possibly diminishing the IJN long range scouting ability. I think it would an interesting mix-up between the two. Night carrier operations and night gunnery duels. Who finds who first.
Of course, HMS Warspite tilts things heavily in Britain's favor.

 

[Wild_Bill_Kelso]

HMS Warspite?

 

[Thumpalumpacus]

On the contrary.

If you can bypass the Philipines, then why not bypass the British holdings and go directly for the oil in Dutch East India? That's what you need for the main show in China. While an empire can never really get too much empire, Japan would probably have preferred to wait with trhe co-prosperity thing untill China was brought to heel. And why on earth would you threaten Australia?

Because Brunei, a large source of oil, was a British holding. Once you take a British holding, you're probably gonna have a fight on yours hands. That means eliminating Singapore, as it's too close to Brunei. And that leaves Australia and Ceylon ...

And if the US is not putting an embargo on the oil, why not just buy it? Or do we 'just' assume that they bypass a hostile USA?

The oil embargo happened long before the war broke out in OTL. Why would that be any different in this ATL?

I'd love to playtest the IJN vs RN board game, but fitting it into history would be a nightmare.

I think you may be overthinking this. The Japanese considered not attacking America anywhere, and decided against it. But that shows it was one possible timeline. At any rate, entering a what-if to simply deny its possibility should probably have a stronger basing than this, imo.

 

[MikeMeech]

Hi
As has been noted it is very hard to get Britain and Japan fighting each other without the actions of the USA taken against Japan over China, indeed the Anglo-Japan agreements may have lasted longer. However, all that can be done is guess what could have happened from the activities of both navies in various situations or actual incidents between the navies.
One incident from 16th May 1945 was the sinking of the Japanese cruiser 'HAGURO' in a night battle with RN destroyers. The armament of the former at the time appears to have been 10 - 8 inch (5x2), 8 - 5 inch DP (4x2) and probably 8 - 21 inch torpedoes (2x4) plus AA. Details of this night action follow:
First from the OH 'The War Against Japan Volume V':

Second from OH 'The War at Sea 1939-1945 Volume III, Part II':

Third from 'Radar at Sea' by Howse, giving details of radar use in the lead up to the battle:

I hope the example is of use.

Mike

 

[mack8]

It's very difficult to ponder this scenario in isolation from events in Europe, but even in the best case scenario for RN (no war in Europe), many of the weaknesses in the RN will still apply.

By far imo is the carrier force, not only the RN CVs carry less aircraft than KB, but the aircraft themselves are still the likes of Fulmar, Albacore, maybe Sea Hurricanes and some Seafires at best, Skuas, Swordfish. As i understand their combat radius is much shorter than KBs, so in a fight the KB could just stay 250 miles out and keep sending strikes at the british force, with little to fear in the way of retaliation. Not only that but Fulmar and Hurricanes proved completely outmatched by the Zero in 1942, and the Spitfire got roughly handled by the same too in 1943. I can't see the british putting 100 strike aircraft over KB within 1 hour like the USN did at Midway, to overwhelm it's defences.

So imo, as far as a 1942 stright carrier fight, all things being equal the RN will be eaten alive, and KB will cover itself in glory. There is the issue of the supposed carrier night-fighting superiority of the british, but this assumes a lot of things, first the IJN will be kind enough not to attack during the day, let itself be tracked, then be kind to stay within 150 miles or whatever the Albacore's combat radius is. That's a lot of ifs, and any british night strikes, not to mention significant damage, would be more of a fluke rathern than something to be expected.

Even fast forward to 1944, you will have at best Barracudas, Fireflies, Seafires (i'm ignoring for the moment the US planes, afterall the UK would not seem/feel into a tight spot to ask the US for help yet since it's only fighting Japan in this scenario - in fact they will be thinking humiliating to do so) against the B6N, D4Y and improved Zeros. The range advantage firmly remains with IJN. And how many fleet carriers can the RN muster in 1944? I can't see them having 15 fleet carriers and 900 planes like TF58 had, even if they haven't lost a single one to date, certainy not the planes as RN carriers generally carried less aircraft compared to KB. And god forbid if IJN hasn't lost any either. To be honest, even the OTL weakened Ozawa's force, with it's undertrained aircrews, would still be a real threat against whatever carrier force the british could muster in 1944, nevermind a better trained and more numerous IJN carrier force. I can't see the british coping with 300 planes hurled at them and escape without serious damage, nor them being able to send 200 planes at 300 miles after Ozawa.

My view anyway.