Rn vs IJN

[EwenS]

Fascinating insight, many thanks for the info. I've read bits and pieces in various places re the cruisers, and it seems in 1940 there was capacity for 10 but none were orderd due to other priorities. Similarly for 1941 and 1942 there was a desire (capacity?) for 7 each, including at least 4 of the 8 inch designs. I have found in Conways some good sumaries as to the wartime programs, but frustratingly it seems to only include ships that were only laid down, not planned but cancelled. Do you have by any chance some short summary of the complete wartime programs including ships by class and including planned but never laid down ships?

It seems there was cruiser planning for 12 Minotaurs and 5 Neptunes as well as 8 inch CAs (Admiral class?). So in this ATL, we can assume that the cruisers OTL delayed by the war (Didos and Fijis) could probably be finished one year early at least, and the subsequent classes/hulls be brought forward a similar amount? Also, likely the Minotaurs might be a 12 gun design.

It is all laid out in detail in Friedman's "British Cruisers" but fragmented over several chapters and Moore "Building for Victory". Note things get confusing because ships ordered under one name were renamed, sometimes more than once, or names were moved between classes, or even types, as cancellations occurred. In summary:-

1940 Programme - lots of plans, including heavy cruiser designs, but nothing concrete.

But 1940 did see the suspension of construction of 5 Didos from the 1939 War Programme and 3 Fijis from the 1939 Programmes, for 5-6 months, allowing their redesign to incorporate War experience and improve stability margins with already increasing top weight requirements, the most noticeable feature of which was that all eventually gained an extra Pom-Pom at the expense of a main battery turret.

1941 Programme - initially 7 ships. 4 heavy 8" cruisers + 3 improved Fijis.

The former design was never formally approved by the Admiralty and kept being postponed. They were eventually cancelled in Aug/Oct 1942 along with their planned new armament. Admiral class 16,500 tons, 656' long, 9x8", 16x4", 4 quad Pom-Pom. To have been named Benbow (later Albemarle), Blake (not to be confused with the postwar ship of the same name), Effingham (later Cornwallis), & Hawke (name reused in 1942 - see below). 3 deferred in late 1941. It had been hoped to lay one ship down in early 1943. Their eventual cancellation came from the deliberations of the Future Building Committee who saw them as too large for the cruiser's new main role as carrier escort.

The latter (and their builders) were Swiftsure (VA Tyne), Bellerophon (John Brown, Clydebank) and Minotaur (Harland & Wolff Belfast. As designed they had 1ft more beam than the Fijis. All 3 were laid down in Oct/Nov 1941 and were expected to complete between Aug 1943 & June 1944. Swiftsure completed in June 1944. Minotaur, as the Canadian manned Ontario, completed in May 1945 but with the latest Mk.VI secondary directors. She had reached Ceylon on her way to join the BPF when the war ended.

Due to competition for allocation of labour at John Brown (first for Vanguard and then Indefatigable had priority), work on Bellerophon was suspended from early 1942. She remained a low priority until well into 1944, finally being launched as Tiger in Oct 1945 to again be suspended before being completed to a new design in 1959.

1941 Supplementary Programme - replaced 3 of the planned 8" cruisers with another further improved batch of Fijis, as the Tiger class. Another 1ft of beam was added to take it to 64ft. These were to have been named Defence (Scotts), Superb (Swan Hunter) & Tiger (VA Tyne). The first 2 were laid down in June 1942 and were originally intended to complete in June & Oct 1944. Superb completed to the original design (except she retained the Mk.XXIII turrets of earlier ships - see below) in Oct 1945. Defence was subject to many delays and was launched in Sept 1944. Postwar she was renamed Lion and completed to a revised design in 1960.

The laying down of Tiger kept slipping due to lack of labour in the yard. At the end of 1942 the estimated laying down date was June 1944, so it was decided to transfer materials already accumulated for her, including her armour, to the Hawke at Portsmouth (see below) to speed her construction. Later it was planned to build her as one of the Neptune class until eventually the name was reallocated to an other ship.

1942 Programme - 7 more Improved Fijis were planned but only 3 were ordered with only 2 laid down, with only 1 ship, Blake (Fairfield) launched in Dec 1945 and completed to a revised design in 1961. The other ship laid down was Hawke (Portsmouth Royal Dockyard) cancelled in Oct 1945.

The ship ordered from Alexander Stephen on the Clyde and the other 4 vessels planned for other civilian naval yards were cancelled in Aug (4) and Oct(1) as a result of the Aug 1942 order for 10 Colossus class light fleet carriers. So the replacements on the slips were Ocean (Stephen), Theseus (Fairfield), Triumph (Hawthorn Leslie), Mars / Pioneer (VA Barrow) & Venerable (Cammell Laird).

The Tiger class of the 1941 Supplementary Programme and the 1942 ships were intended to carry a new triple Mk.XXIV 6" turret with elevation increased to 60 degrees for dual purpose use.

1943 Programme - 3 cruisers were wanted, but to order them in 1943 meant repeating the Tiger design which the Future Building Committee did not want to do.

1944 Programme - with the FBC determining in 1942 that the carrier was now the core of the fleet, the role of the cruiser was now seen as a carrier escort requiring a DP armament for which the only weapon immediately available was the 5.25" gun. From there evolved a string of designs with 3 or 4 twin or triple 5.25" turrets. That culminated in the selection of the Design N2 8,650 tons standard with 4 twin 5.25" + light AA + 2 quad TT on an essentially Tiger sized hull and protection with speed 29 knots. 5 unnamed ships to be built at John Brown, Hawthorn Leslie, VA Barrow and Devonport and Portsmouth Royal Dockyards.

First Sea Lord Sir Dudley Pound resigned 9 Oct 1943 and died less than a fortnight later. His replacement was Sir Andrew Cunningham (ABC) who had commanded the Med Fleet through most of the war up to that point, so had plenty of experience of cruiser actions. His preference was for a 6" cruiser with the design starting as an improved Belfast but with a 6xtwin 4.5" secondary armament.

But the 5.25" ship did not die immediately, it lingered on into 1944 as a ship to work with the destroyer flotillas. The discussions by the FBC in Aug 1944 about such use may well have been influenced by the work of the modified Didos Bellona and Black Prince working with the destroyer flotillas in the Channel and off the Biscay coast from Dec 1943. Ultimately however the talk went nowhere.

Design work on the new 6" cruiser began in Feb 1944 and developed into Design Y, later referred to as the Neptune class, which was still being tweaked in spring 1946. It was an altogether larger ship. 15,350-15,560 tons, 655ft x 76ft, 4 triple Mk.XXIV 6" turrets, 6 x twin 4.5", 32 knots. 5 ships were planned, replacing the N2 design, then in early 1945 it was decided that Tiger from the 1941 Supplementary Programme, and still not laid down, should be built as a 6th ship of the class.

They survived the end of war cull with the intention to lay down 2 in April 1946, which never happened. The design was then superseded by the postwar Minotaur class with 5 twin DP turrets in place of the mixed 6"/4.5" battery.

But it should be noted that the expectation was that none of these 1944 cruiser designs would be in service before 1948/49.


Other cruiser designs that arose during WW2 that never resulted in steel being laid down include:-

Russian cruiser of 1940.
In 1939 8 sets of cruiser turbines for Russia were being built in Britain. A design (Design C) was drawn up in spring 1940 for 2 AA ships to use these along with 4x twin 4.5" (left over from the cancelled D class conversions). Came to nothing due to lack of accompanying boilers and cancelled in summer 1940.

"1943 Cruiser"
Short lived design developed in mid 1942. 12,000 tons standard, 9x6" + light AA. Superseded by deliberations of the Future Building Committee.

This is very much a brief(!) summary of what went on in arriving at each of these designs and Programmes. There were many twists and turns along the way.

Incidentally the Colossus class light fleet carriers used a half set of Fiji class machinery.

 

[Shortround6]

I am not sure what makes navigating over the ocean necessarily more perilous than navigating over land, in fact many people in this forum have repeatedly insisted that navigating over the Pacific is less problematic than flying long distances over Continental Europe, specifically because unless you are flying near an enemy island base (or the unlikely event you get caught by an aircraft carrier) you can safely fly at much lower speed, and won't be targeted by either fighters or AA along the route. So, compared to flying from England to Berlin, you may be able to get farther and a bit safer along route on the way to Java from Broome.

Flying without getting shot at is different problem than flying without knowing where you are.

This also brings in training and experience. A lot of times the RAF did not know where they were in 1940/41. Bombed the wrong country at times and often the wrong county or city.
Yes they got a lot better but it took combat experience, training and equipment to do it.

At times (barring fog, clouds and such) over land you can sometimes pick out landmarks. Rivers, large lakes, coast line. You don't get that over the water. Unless you have a few convenient sizeable islands that can be used as waypoints. Back to visibility, and can you see pongo-pongo before you turn 20 degrees to the right for the next leg? Problem over water is how far is the next check point.

As far as the PBY's go. There wasn't any difference in the aircraft (mostly) the difference was the crew and the training. The PBY crew/navigator was expected to do more than just get from base to target and get back without too many getting lost. They were expected to spend a number of hours in air and subject to wind drift and the basic mission was to spot enemy ships and then to give report with an accurate location by radio back to HQ. If the PBY was lost or was doing bad navigation the spotting report was not anywhere near as valuable. I am not saying that they didn't get lost or didn't make mistakes. But the expected performance was higher than for standard bomber crews. Which is part of the reason that bomber forces used pathfinders.

For instance in bomber raid to attack Hamburg (360-370 miles from Norwich) The British crew has 10-15 miles to cross the British coast, about 130 miles to cross the Dutch coast (island), 25 miles(?) to mainland, about 110-120 miles to the EMS (Emden on your left) about another 50 miles to Jade and another 10 miles to the Weser and another 60 miles to downtown Hamburg. If you are a running a little north you will pick up the Elbe abut 10 miles early. If you miss there are a couple of sizable lakes about 30-35 miles ENE and if you miss to the south the Elbe (skinner) runs pretty much SE. A lot of redundant landmarks if you miss one or two.
This is actually a pretty crappy route as it the Germans maximum notice. Fly above Holland about 20 miles outside the Frisian Islands (or whatever blocks most of the radar) and head for the coast between Cuxhaven and Bremerhaven. There is a 10-15 mile nearly straight section of coast that cannot be confused with anything else within a 100 miles (orientation and length) And from there it is about 60 miles to Hamburg with the last 10-15 miles running right down the Elbe.
Yes crappy weather can screw things up.

Now fly over water for 2-5 hours. You had better be good with the sextant.

 

[Glider]

All nations had a lot of experience of flying long distances over water if only on anti submarine patrols. So if Coastal Command can do it, why not bomber command?

The Wellington was quite a good torpedo bomber, not many aircraft could carry two torpedo's internally. However if your talking about 1942 and attacking land targets, then the four engine bombers are on stream with significant increases in range and payload.

As has been mentioned Beaufighters are exceptionally effective anti sipping strike aircraft, and at close to 300mph at low altitude (carrying a torpedo), would take some catching.

 

[Wild_Bill_Kelso]

Well navigating by the stars is something people have done for ... millennia. That is how the Polynesians spread around the Pacific, it's basically how the Vikings got the Newfoundland and back and forth to Greenland and Iceland, and how the Arabs spread Islam to Malaysia and Indonesia. Add the compass about 700 years ago, and along with some tricky math (typically featuring trigonometry, as unlike today 'flat earth theory' was not very popular in the middle ages, and they knew they had to account for the curvature of the earth) they were going across deep bodies of water in small, fragile ships, many of them powered mainly by oars, on such a routine basis that entire new mercantile industries were born. Sextant dates back to the 17th Century and was being use successfully on a large scale for navigation since the mid 18th.

In fact it's one of the main reasons why all those European colonies in Java and Malaya etc. existed, as we know.

One of the problems in Northern Europe is that high cloud cover often obscured the stars. By definition, you need to see the stars to perform celestial navigation. This is generally less of a problem in the vast Pacific.

To overcome this, the British used various radio direction finding systems. Something like that could have been set up in Australia, though it may not have been necessary.

You make a fair point about how well trained the PBY crews were as navigators. I don't dispute that. My point was that Wellington aircraft are better as bombers. For example they can carry most of their bombs internally, they can carry more bombs, they are better defended, and they have good bomb sights right out the gate. PBYs eventually got norden sights but I don't think that was right away. Most of the 'Black Cat' bombing missions were at low altitude anyway.

I also agree about the idea of pathfinders. Why not use some of those highly trained flying boat crews, like those of Sunderlands who the British had plenty of, to act as a pathfinder? The Sunderlands don't have quite the range of a Wellington but they have the advantage that you can set a few of them up in some remote island or part of the New Guinea coast, say, and resupply them with submarines.

Finally yes you do make a fair point about landmarks. But in Nothern Europe the ground was also often obscured. Meanwhile in the Pacific, while it's true there would be a long patch of flight over open water, once you do get to the archipelagos, those are some big islands. They are hard to miss, as they pretty much completely cover the route east to west if you are flying north from Australia. These islands have distinctive coastlines which can be matched to little pictures in the navigators case.

There are also mountains. Mount Kerninci in Sumatra is 12,000 ft high. Hard to miss that baby. These can also be used as landmarks.

 

[Shortround6]

So if Coastal Command can do it, why not bomber command

Training.
Training.
Training.

Bomber command actually did very little over water training 1937-38. Let alone flying anywhere but 0ver the UK.
It was hard to "Bradshaw" overwater.

You had a massive expansion going on and just getting the crews trained to a sort of minimum standard took precedence.
At least one major accident (5 or 6 planes lost?) ended a lot of night flying. The early Whitley's (first 50-60?) with Tiger engines were banned from flying over water. It would interesting to learn the story on that one.

 

[Glider]

Training.
Training.
Training.

Exactly, with some training, Bomber Command could do it as they did with the Pathfinders.

The early Whitleys with Tiger engines should have been banned from flying, full stop.

 

[Shortround6]

The main limitation was training. Yes sextants existed for hundreds of years, but you can't just hand somebody a sextant, a book of charts/tables and a map and say "go to it".
Not everybody got the hang of it even on a sailing ship doing 6-10kts. Now do it on airplane doing 150-200kts. How far are you traveling if you need to re-shoot the star fix.
RN was training the future officers from boyhood (OK early teenagers).
Yes most Wellingtons had Astro domes.

Just about mid wing.

To overcome this, the British used various radio direction finding systems. Something like that could have been set up in Australia, though it may not have been necessary.

It is a lot harder to get it to work, The radio beams do not follow the curve of the earth (somewhat depends on Frequency) and they (in WW II) didn't work well at long ranges.
Although the higher you flew the longer range the system had.
Now the Tear Drop shape behind the cockpit was the radio direction finder. But again there was only so much range.

 

[Wild_Bill_Kelso]

I get that it's harder to plot a course with a sextant when going 200 mph than 10 mph, but that is what the slide rule is for. The fact remains that since the 18th Century the British, French, Americans and all the others taught many, many people this secret, and had literally thousands of people who knew how to do this at any given point, and they certainly had a lot of people who could during WW2. The RN I'm certain had plenty of very well trained navigators and so did Coastal Command, and many of these chaps could join the bombing effort, assuming they wanted to win the war.

Again, to wreck industry in Java or Malaya I don't think you are going to need 1,000 bomber streams. I'm talking about raids like the Japanese were doing against Darwin or Rangoon, with a few dozen planes. Maybe 100 at peak effort.

US pilots in P-38s and F4Us and P-51s were managing to find their way on quite long flights around the pacific while piloting their aircraft. Pilots were flying P-40s and C-47s in complex routes through the Himalayas. In the early days yes they often used Hudsons and so on which had the trained celestial navigators in them with the little astrodome, and they also had the RDF loops too... but US Navy PBY and later B-24 and PB4Y, and US army B-17s and various medium bombers... and RAF Hudsons, Beaufighters and Beauforts were navigating their way all around the South Pacific. So I think it's doable.

Early on, initially a lot might rely on the one or two crews with the better trained 'Pathfinder' navigators, but after a while more of the 'basic' navigators will learn the routine.

 

[Wild_Bill_Kelso]

Anyway, I'm not saying they could get this working effectively overnight, but I do see this as one weapon they could use to eventually claw their way back from the brink. The Japanese never seemed to adjust very well to night time air raids.

 

[Shortround6]

Just crossed

A lot of things change over the 6 years of the war. Training got better, a lot better, radios got better, electronic navigation equipment got better, sometimes there was more that one jump or level. What could be done in late 1944 or 45 sometimes was not what could be done in 1943 let alone 1941.

My Idea of the scenario is to start in Dec 41/Jan 42 with the conflict in Europe just changed somewhat so that all or at least most of the changes in equipment, training experience and that occurred in 1939-40-41 are carried over. Yes the British are going to have losses.

But with no combat we have to try to figure out what the British coulda, woulda, shoulda changed before the hypothetical scenario starts. A whole lot butterflies

We do know that the RAF navigation skills over Western Germany were less than stellar during much of 1941.
CC Navigation skills may have been very different.

Now if we can figure out how to get enough war material into the Far East in the 3-6 months before the Japanese attack, the British may have a good chance to stop them and then slowly push them back.

The 29 US Subs in the Philippines did next to nothing (4 ships?) over about 3-4 months. And the old S boats (6 of them) did at least 1/2 the kills.
The Dutch subs did much better.
15 or so British subs (experienced) based at Singapore might have made some significant changes if coupled with several hundred extra aircraft but these forces would only be available if NA was in British hands.

With the Philippines staying in US hands for this scenario the Japanese are going to have to use some of their carriers for air support and not leap frog aircraft down through the Philippines to support the DEI attacks.

 

[Wild_Bill_Kelso]

Just crossed

A lot of things change over the 6 years of the war. Training got better, a lot better, radios got better, electronic navigation equipment got better, sometimes there was more that one jump or level. What could be done in late 1944 or 45 sometimes was not what could be done in 1943 let alone 1941.

My Idea of the scenario is to start in Dec 41/Jan 42 with the conflict in Europe just changed somewhat so that all or at least most of the changes in equipment, training experience and that occurred in 1939-40-41 are carried over. Yes the British are going to have losses.

But with no combat we have to try to figure out what the British coulda, woulda, shoulda changed before the hypothetical scenario starts. A whole lot butterflies

We do know that the RAF navigation skills over Western Germany were less than stellar during much of 1941.
CC Navigation skills may have been very different.

Now if we can figure out how to get enough war material into the Far East in the 3-6 months before the Japanese attack, the British may have a good chance to stop them and then slowly push them back.

The 29 US Subs in the Philippines did next to nothing (4 ships?) over about 3-4 months. And the old S boats (6 of them) did at least 1/2 the kills.
The Dutch subs did much better.
15 or so British subs (experienced) based at Singapore might have made some significant changes if coupled with several hundred extra aircraft but these forces would only be available if NA was in British hands.

With the Philippines staying in US hands for this scenario the Japanese are going to have to use some of their carriers for air support and not leap frog aircraft down through the Philippines to support the DEI attacks.

I see what you are getting at - it's very hard to discuss this with much granularity without grounding it in some kind of specific scenario vis a vis the war (or lack thereof) in Europe. Personally I am fine with the British still having North Africa - I think they will still have a very tough time in the Pacific. Of course, if the Germans didn't challenge them there maybe they wouldn't have all the US made aircraft they got. On the other hand, if France was knocked over in 1940 they would have some of it since a few of their most successful aircraft in the Western Desert (Tomahawk, Maryland, Boston) were taken over from French orders.

I am agnostic on all this. I'm ok with testing various scenarios, but as you point out, the butterflies start to multiply the more you tinker with the alternative timelines. The point I wanted to make is that the RN was not exactly towering over the IJN, and in fact the British would have been quite challenged to face down the Japanese on their own in 1941-1943, even if there wasn't a war in Europe. They might win eventually, as we can see there are some gaps in the Japanese panoply so to speak, but I am pretty confident they would be hard-pressed at the outset. It's no guarantee they would prevail, because the Japanese were quite resourceful too.

And the UK had the mightiest navy in Europe, by far. So where does that put Japan compared to Europe in general? Germany, France, Italy, Holland, none of them could face the IJN.

 

[WARSPITER]

The consensus is that Britain would be hard pressed at the beginning of any
attempt by Japan to expand aggressively. This was the actual case at the time
and included US interests as well.

Initially Japan was faced with weak opposition and took advantage at the time.

What happens from 1942 on is the question and long term strategy as far as Japan
went was flawed.

Holding so many positions which are tenuously connected by sea is difficult enough
but the lack of foresight in some areas is staggering.

As an example, Japan needed nickel so badly that even before hostilities started
they were buying coins from Hong Kong and melting them down because they
contained nickel.

The development/ non development of radar reads like some kind of Greek tragedy.

IJN vs IJA rears it's ugly mug to the Nth degree in this one.

Development was totally separated to the point where technicians from one arm
were forbidden any contact with their opposite numbers in the other arm. Hence no
sharing of information / equipment.

Some sites in Cities / ports on mainland Japan ended up with an IJA radar system set up
next to an IJN system.

Technology wise, Japanese developers came up with the cavity magnetron before
other countries did but no one bothered to explore the possibilities so the lead was
totally wasted.

When Japan took Singapore they got British radar sets and found out about the
Yagi-Uda antenna which was the thing that allowed directional pickups. The odd
part of this is that it was invented and patented in Japan in the mid 1920's. The
patent was transferred in the US to RCA and in the UK to Marconi. We still use
derivatives today for TV antennas. Japanese developers didn't know about
it or hadn't clicked as to it's possibilities.

Technicians and developers were put into the work on radar etc in numbers
that simply didn't compare. The US and Britain had literally thousands of
people involved in development of radar whereas Japanese numbers were
only ever in the hundreds.

The list of woes goes on - even aluminium chaff or window was used but only
sparingly as aluminium was also only available in low quantities. The name for
Japanese window was the rather quaint "deceiving paper".

The first airborne radar developed for Japanese torpedo bombers was so heavy
the plane carrying it couldn't actually carry a torpedo. At the same time Allied aircraft
already had H2S and the like in smaller sets.

All in all, this meant Japanese radar wasn't good quality and was generally around
3 years behind anything the allies had. Fire control and fighter direction radar was
basically hopeless. Searchlight and AA control radar was poor as well.

The main radars available became air, sea, and general early warning sets. Even
these were mostly copies of captured British and US types. One British type captured had
all the gear for range control etc which was left off copies made because no one
could work out what it was for.

IFF was a disaster. Allied IFF was shared so any allied radar system could identify
other nations ships or aircraft - makes sense of course.

Not when it came to IJA vs IJN. They developed IFF that worked. The problem was they
developed seperate systems which did not communicate with each other. A recipe for friendly
fire incidents every day of the week and basically a truly bizarre situation to get into.

Add to this the poor quality control which meant valves in sets needed replacement
often and the systems made became could have / should have beens.

Apologies for the post length.

 

[Wild_Bill_Kelso]

The consensus is that Britain would be hard pressed at the beginning of any
attempt by Japan to expand aggressively. This was the actual case at the time
and included US interests as well.

Initially Japan was faced with weak opposition and took advantage at the time.

What happens from 1942 on is the question and long term strategy as far as Japan
went was flawed.

Holding so many positions which are tenuously connected by sea is difficult enough
but the lack of foresight in some areas is staggering.

As an example, Japan needed nickel so badly that even before hostilities started
they were buying coins from Hong Kong and melting them down because they
contained nickel.

The development/ non development of radar reads like some kind of Greek tragedy.

IJN vs IJA rears it's ugly mug to the Nth degree in this one.

Development was totally separated to the point where technicians from one arm
were forbidden any contact with their opposite numbers in the other arm. Hence no
sharing of information / equipment.

Some sites in Cities / ports on mainland Japan ended up with an IJA radar system set up
next to an IJN system.

Technology wise, Japanese developers came up with the cavity magnetron before
other countries did but no one bothered to explore the possibilities so the lead was
totally wasted.

When Japan took Singapore they got British radar sets and found out about the
Yagi-Uda antenna which was the thing that allowed directional pickups. The odd
part of this is that it was invented and patented in Japan in the mid 1920's. The
patent was transferred in the US to RCA and in the UK to Marconi. We still use
derivatives today for TV antennas. Japanese developers didn't know about
it or hadn't clicked as to it's possibilities.

Technicians and developers were put into the work on radar etc in numbers
that simply didn't compare. The US and Britain had literally thousands of
people involved in development of radar whereas Japanese numbers were
only ever in the hundreds.

The list of woes goes on - even aluminium chaff or window was used but only
sparingly as aluminium was also only available in low quantities. The name for
Japanese window was the rather quaint "deceiving paper".

The first airborne radar developed for Japanese torpedo bombers was so heavy
the plane carrying it couldn't actually carry a torpedo. At the same time Allied aircraft
already had H2S and the like in smaller sets.

All in all, this meant Japanese radar wasn't good quality and was generally around
3 years behind anything the allies had. Fire control and fighter direction radar was
basically hopeless. Searchlight and AA control radar was poor as well.

The main radars available became air, sea, and general early warning sets. Even
these were mostly copies of captured British and US types. One British type captured had
all the gear for range control etc which was left off copies made because no one
could work out what it was for.

IFF was a disaster. Allied IFF was shared so any allied radar system could identify
other nations ships or aircraft - makes sense of course.

Not when it came to IJA vs IJN. They developed IFF that worked. The problem was they
developed seperate systems which did not communicate with each other. A recipe for friendly
fire incidents every day of the week and basically a truly bizarre situation to get into.

Add to this the poor quality control which meant valves in sets needed replacement
often and the systems made became could have / should have beens.

Apologies for the post length.

All this is interesting. But the thing is, every nation had their blind spots, their errors, the cultural flaws, their shocking omissions in preparation for the inevitable war. You are focusing a lot on radar, which England was ahead on and Japan behind (but, not so behind that they didn't figure it out). But it is just as shocking and incomprehensible that the Royal Navy having a two person, 270 mph fighter, and a biplane strike aircraft for their carriers. Or the US having a torpedo that didn't work for the first 3 years of the war. Or why the early British tanks were so bad. Etc.

The Japanese had the best carrier fighter in the world in 1941, and it still was until the Hellcat showed up in mid 1943.
The Japanese had the world's best naval torpedoes basically until the end of the war. By a wide margin.
The Japanese had the best naval optics in the world, which ended up being copied by both the US and the UK
The Japanese navy leadership and sailors were some of the best trained in the world for night combat
The Japanese had some of the best trained aviators in the world
The Japanese had either the best, or the second best naval strike aircraft in the world 1941 in the D3A
The Japanese had one of the most disciplined, aggressive land armies in the world in 1941.
The Japanese had the largest and most powerful battleships in the world by the end of 1941.
The Japanese had the best float plane fighter in the world in 1941-43 in the A6M2-N. After that they got the even better N1K1.
The Japanese had the best flying boat in the world in the H8K
The Japanese had the best, or second best aircraft carriers in the world in 1941

These are all irrefutable facts. We can debate about how good the Ki-43 was (I think, very good) or how the A6M stacked up against European land based fighters (I think quite well) or how well the Japanese bombers held up and so on. But the list above is enough.

 

[Greg Boeser]

All this is interesting. But the thing is, every nation had their blind spots, their errors, the cultural flaws, their shocking omissions in preparation for the inevitable war. You are focusing a lot on radar, which England was ahead on and Japan behind (but, not so behind that they didn't figure it out). But it is just as shocking and incomprehensible that the Royal Navy having a two person, 270 mph fighter, and a biplane strike aircraft for their carriers. Or the US having a torpedo that didn't work for the first 3 years of the war. Or why the early British tanks were so bad. Etc.

The Japanese had the best carrier fighter in the world in 1941, and it still was until the Hellcat showed up in mid 1943.
The Japanese had the world's best naval torpedoes basically until the end of the war. By a wide margin.
The Japanese had the best naval optics in the world, which ended up being copied by both the US and the UK
The Japanese navy leadership and sailors were some of the best trained in the world for night combat
The Japanese had some of the best trained aviators in the world
The Japanese had either the best, or the second best naval strike aircraft in the world 1941 in the D3A
The Japanese had one of the most disciplined, aggressive land armies in the world in 1941.
The Japanese had the largest and most powerful battleships in the world by the end of 1941.
The Japanese had the best float plane fighter in the world in 1941-43 in the A6M2-N. After that they got the even better N1K1.
The Japanese had the best flying boat in the world in the H8K
The Japanese had the best, or second best aircraft carriers in the world in 1941

These are all irrefutable facts. We can debate about how good the Ki-43 was (I think, very good) or how the A6M stacked up against European land based fighters (I think quite well) or how well the Japanese bombers held up and so on. But the list above is enough.

How many ships did Yamato sink?

 

[Wild_Bill_Kelso]

How many ships did Yamato sink?

Two, apparently, which is more than the HMS Prince of Wales did.

 

[SaparotRob]

Which two?

 

[Wild_Bill_Kelso]

Which two?

One of the destroyers and one of the CVE's at the Battle off Samar.

 

[EwenS]

Back in 1996 the RAF Historical Society arranged a seminar with speakers tracing the development of RAF air navigation through the years. These talks were published in the link below. Of particular interest to this discussion are the talks on the inter-war period, "epic" flights and WW2 developments.

Note navigation inter-war was a pilot's job. The RAF only began again to train "Observers" as navigational specialist aircrew from Oct 1937 (that "trade" having been abolished in the aftermath of WW1). Until then the best "navigators", who were few and far between, seem to have been in the flying boat squadrons, but those units themselves were few in number inter-war. There is a comment in the WW2 section that the number of RAF Officers that undertook the "Long Navigation Course" to become specialist navigators numbered just over 100 between 1920 and 1939. In the earlier part of that period it was about 2 per YEAR!

There is also a paragraph that details Coastal Command late war navigation procedures that reads:-

"A summary of the drills in use in the later stages of the war serves to illustrate the manner in which navigation routines had developed over only a very few years. It is axiomatic that a comprehensive flight plan would be prepared. As a basis for accurate track-keeping Coastal Command laid down an hourly drill requiring: four drifts; one three- drift wind velocity; one fix or MPP (Most Probable Position) and one recommencement of the air plot. The maintenance of a trackplot was also recommended, as was regular checking of the compasses by astro compass."

Given the workload, it is hardly surprising that many large CC aircraft flying long sorties carried two navigators in the late war period.

There are also some interesting comments in the morning Q&A p63 about US standards of navigation training.

https://www.rafmuseum.org.uk/documents/research/RAF-Historical-Society-Journals/Journal-17A-Air-Navigationin-the-RAF.pdf

There are biographical notes on each of the speakers from p136, some of whom trained as navigators during WW2.

 

[Geoffrey Sinclair]

The irrefutable facts list,

By end 1941 all 3 RAF four engined bombers were in production, forget Wellingtons and the other twins, an at peace RAF would be phasing them out and would be worried about fabric covering in the tropics.

There were no SAAF Wellington squadrons until 26 squadron in May 1943, and then it was mark XI for GR work. Then came 28 Bomber squadron in July 1943. As of February 1943 the RAF in India held 47 Wellington Ic and 14 Wellington Ic torpedo bombers.

The RAF learnt a lot about how to do effective bomb damage from Luftwaffe raids. The one pre war trial on staked out aircraft showed how little damage was done.

The Arthur Harris Accuracy table, notes bombs within 3 miles of target in German cities (except Berlin) shows under 25% in early 1942, around 28% in April 1943, hitting 50% in June, staying at 50 to 60% until April 1944, reaching 88% in December. The accuracy problem was not solved in 1942.

What was possible in 1943 at much shorter distances with experience built up over 4 years is not the same as what was possible earlier. The US introduced Loran in 1942 firstly for ships, then for aircraft.

Spitfire V and IX float planes were trialled.

One of the early Dutch submarine successes was sinking a ship containing Japanese oil industry people and their equipment. Yes the Japanese resilience is lower, but then again they did not need the local refineries working well until they hit refinery capacity in Japan or tanker capacity, whichever is less. Sinking the ships would be a better solution than bombing the refineries.

The USSBS notes how resilient oil targets were, lots of the production losses were due to disrupted gas and water supplies, not equipment damage.

The reality is the amount of effective sabotage the allies would be able to do before occupation would make a bigger difference than bombing campaigns at long range, unless the bombing went on for enough time.

The Palembang refineries were about 50 miles inland, it was the area that had about 75% of Dutch East Indies production. Lutong is on the coast, as is Balikpapan. Palembang minimum monthly rainfall is around 3.3 inches in August, maximum December at 12.3 inches. Balikpapan range 5.6 inches in September, 12.9 inches in January, at around 103 inches of rain a year, versus Berlin at 11 inches of rain plus 5 inches of snow a year. Lots of rain means lots of clouds.

Japan's pre war crude oil output was around 7,271 barrels per day, Dutch East Indies 170,101, Brunei 19,444, finding the people to keep crude production going was the first task, Japan pre war was refining around 42,000 barrels of imported crude per day. Refineries in the Dutch East Indies and Borneo areas came to around 197,000 barrels per day. Palembang was back on line within 3 months, and worked up to more than pre war levels, it took until September 1942 for a limited restart of Balikpapan and another 4 months for Sungai Gerong (Palembang). The Lutong refinery in Borneo was rebuilt, taking 2 years. Some 7,000 Japanese oil workers moved into the area, to be replaced by the untrained and some slave labour, Japanese home production dropped 10%.

Japan ruled the force that captured the oil facility would control it. Refineries score: Army 3 Sumatra, 1 Borneo, 2 Java, plus oil fields, Navy 1 Balikpapan, oil: 85% Army, 15% Navy. And it was finders keepers until some sense prevailed, until then it was navy used its monopoly on transport to counter army monopoly on supply.

All air forces trained their navigators to a series of levels, the highest was for over water. Pre war the RAF "knew" that above 10,000 feet in Europe the stars were usually visible. Navigation errors distance wise tend to increase with time in flight, compass errors accumulate, clock drift, the slower you are going the more you need to worry about things like winds and so on. Good crews worked to make the navigation fixes as efficient as possible, starting with keeping the aircraft steady and helping the navigator. In May 1941 when the sighting reports came in for Bismarck, after around 6.5 hours in flight the Catalina was 25 miles out, Bismarck was around 80 miles out. During the night action U-556 reported Bismarck was 60 miles from where it said it was.

We are not talking about the Pacific, but the area around the South China Sea. The proposed battle zone is subject to Monsoons, with Malaysia being part of the boundary between systems

Mumbai, India from June to October
Bangkok, Thailand from April/May to October/November
Kelantan, Malaysia from October to March
Darwin, Australia from October to April
Typhoon/Cyclone season in Hong Kong is April to October, Australia November to April.

Rain forests spend their time pumping water into the atmosphere, which tends to return as afternoon rain if the forests are big enough. The tropical ocean has lots of evaporation. Tropical islands therefore have a tendency to be marked by clouds, at least the ones that have enough elevation, but climate varies, you only have to look at the Galapagos to see that.

The British did initially have problems targeting cities at night in 1940 - early 1941, but IIRC these were mostly worked out

No.

but for sure by this time they (mostly SAAF) were hitting all kinds of targets, from individual ships to airfields and ports, even columns of trucks, with fairly good precision all around the Med, using Wellingtons at night

No. Wellington were certainly being used on night raids.

The Germans were certainly ahead of the Japanese both in terms of industrial capacity and air defense. Refineries, ports and airfields in the Far East were not as built up as those in Central Europe. When a refinery was damaged in say, Romania, major components, supplies, skilled labor and parts could quickly be brought in by rail from nearby manufacturing centers. On-site foundries and machine shops could make parts and tools needed for smaller repairs. This was not necessarily the case in Java or Malaya, in fact most materiel needed to repair damaged industrial facilities of any kind would have to be brought in by ship.

Lots of freight moved along the Danube, including oil for Germany, in any case consider the counter, the further away you are the more self sufficient you need to be when it comes to repairs and replacements, otherwise you lose a lot of production while waiting The European Oil Industry was bigger, it had more resources, starting with Romania itself.

I suspect Far Eastern industrial sites are more vulnerable, in part based on the rather immense amount of damage caused by a relatively small number of small to moderate sized raids consisting of fairly lightly armed (max 2,000 lb bomb load) aircraft. Such as IJA Ki-21s and IJN G3Ms and G4M against British controlled facilities in both Malaya and Burma, and against Australian and USAAF bases around Darwin.

What was the lasting damage to Darwin? Not the loss of aircraft but the airfields knocked out for long periods of time. Similar for the other targets. The post war research showed bombing had to be sustained and usually caused repairable damage.

I am not sure what makes navigating over the ocean at night necessarily more perilous than navigating over land at night.

In peace time, much easier to get lost, similar in wartime.

In fact many people in this forum have repeatedly insisted that navigating over the Pacific is less problematic than flying long distances over Continental Europe, specifically because unless you are flying near an enemy island base (or the unlikely event you get caught by an aircraft carrier with night-capable fighters) you can safely fly at much lower speed, and won't be targeted by either fighters or AA along the route. So, compared to flying from England to Berlin, you may be able to get farther and and with a bit more safety along route on the way to Java from Broome.

The reality is the supply and warning systems in the Pacific generally meant aircraft had little chance of en route encounters which is irrelevant to the navigation problems of knowing where the aircraft was. It does mean the aircraft can stay at economic cruise giving a greater range. Mixing up the chance of being attacked and figuring out where you are is wrong.

There is of course the threat of bad weather in various forms in the Pacific, but you get a lot of fog and cloud cover (blocking the stars) in the North Sea / Baltic Sea zones, and North-Central Europe more generally. In the Pacific, you have a lot of squalls and storms, but not necessarily solid cloud cover at 30,000 feet for hundreds of miles (unless there is an active Typhoon).

Which weather site are you using to determine relative cloud densities at different altitudes at the locations? Note the rainfall figures.

US forces adapted to conditions in the Pacific fairly quickly, sufficient to be able to conduct effective strikes, if not to completely eliminate the risk of mission-aborts or losses. And so did the RN eventually. I suspect there are tradeoffs, neither situation is ideal if you have engine trouble two hours into your flight. But I don't think Pacific should be vastly more difficult than flying over Benelux and lower Saxony.

What does fairly quickly translate to, and effective for that matter? Over water navigation is actually harder, so say all the experts.

Black painted PBY Catalinas (so called "Black Cats") were being used to carry bombs and torpedoes long distances over the Pacific to strike Japanese shipping, ports, and airbases at night with relative impunity and a fairly high rate of success, again by 1942 (one of them hit a ship with a torpedo at Midway).

A remarkable way to have one off strikes being turned into sustained campaigns, the Midway ship was damaged. Can you provide a summary, numbers etc, say from Air War Pacific from Hammel? The USSBS notes Japanese merchant ship losses to mines were 5 to May 1942, then 1 in September and another in November 1943. Navy land based air sank 18 ships August 1942 to February 1943, then 1 in May then 1 in December. In 1942 the PBY was in short supply and needed for a lot of defensive patrol work. In this what if the Japanese can route merchant ships via the east coast of the Philippines to minimse exposure. When was Rabaul or at least the port and airfields there totally destroyed, it was the number one target for a long time, by Pacific standards lots of bombs dropped.

Much like the Wellingtons were being used at that same time by SAAF units in the Med, and not too long after, (or so I gather) from bases in India.

No to SAAF.

I think Wellingtons, which are better bombers than a PBY, and which ultimately turned out to be particularly effective in the night intruder / night raid missions, would have had the potential to cause significant damage to the (I believe, fairly fragile) infrastructure of Japanese bases in the former colonial urban centers and logistics hubs.

No, more so if it is a 500 pound bomb load.

They were flying raids IIRC from India from not too late in the war, although I don't know a lot of details about this operational history yet. Not sure if there were any Wellingtons based in Australia in the war but I'm sure someone here does. Anyway, they certainly could have been sent there.

215 squadron arrived in India in April 1942.

When it comes to building up forces in Australia, no Wellingtons made it, the distance is 930 miles Darwin to Alice Springs rail head, Darwin officially had 944 people, Northern Territory 4,591 people. Start with how good that road was before even thinking about how much capacity the rail link would have. Bases in Northern Australia meant "in fact most materiel needed to repair damaged … facilities of any kind would have to be brought in by ship."

The Wellington raids are a non starter.

 

[EwenS]

Back to the bigger combatants, so we probably expect another 2 Implacables to be laid down in 1940-41 ready in 1943, and another 2 Implacables or perhaps Irresistibles in 1941-42 (ready 1944-45 at best). There will be probably 6 Lions building by 1942 plus Vanguard, though the war will almost certainly result in delaying/cancelling the last 2 Lions, as well as many of the 20 plus cruisers building under the ATL 1940, 1941 and 1942 programs, or on order.

So it seems in the all important CV matchup, at best RN would have 10 fleet carriers in 1942 (Ark, 3 Follies, 6 armoured), plus Eagle and Hermes with roughly 450-475 planes on board at best, faced with the 6 KB carriers, 2 Junyos, Ryujo, 2 Zuihos with something like 550 planes. The RN will only add another 4 Implacabels or Irresistibles by 1944-45, plus whatever emergency CVL would be ready under a 1942-43 wartime program. Still to me it seems the RN on it's own will have nothing like the USN crushing fleet carrier superiority in 1944-45, not to mention many tens of CVEs.

In Sept 1939 the Admiralty were expecting to complete the Implacable & Indefatigable in about 36 months from order (32 months from being laid down). Probably not unreasonable given the delays to Illustrious class with problems like getting some of their armour from Czechoslovakia. Assuming British armour production was being built up as historical that bottleneck could probably have been avoided. So delivery as noted in my previous post 10/41 & 6/42.

As for future ships, it depends on when the money is made available by the Treasury. The earliest would normally be April, the start of the financial year, but occasionally they could be persuaded to allow orders to be placed before that e.g. DoY, Formidable. More usually the orders would be placed later in the financial year. Without imminent war in 1939-41 there is less pressure to place orders early.

So depending on when the orders are placed the 1940 carriers could appear anytime from April 1943 to March 1944 assuming no other delays but probably nearer the end of 1943. And the 1941 ships nearer the end of 1944.

Then there is the question of the design. Does the Treaty limit of 23,000 tons standard still exist? Yes/no probably means repeat Implacables or an entirely new design. The Irresistible design was intended as a minimum change to Implacable to incorporate War experience to 1940/41 without the tonnage restriction. With no European war the design capacity might exist for a new and better carrier for 1941.

As I've already noted the RN Far East plan saw only 4 carriers at Singapore. That was based on the planning that the RN had carried out in 1938 regarding the overall carrier numbers it required. Even when it was reassessed in 1940 that figure didn't change. Ark (60 aircraft reduced to 54 when she received Fulmars in place of Skuas and set to drop further when she got Albacores/Barracudas as replacements for her Swordfish), Indomitable (45) and the two Implacables (48 each). Capacities based on hangar capacity and based around Albacore/Fulmar/Barracuda sized aircraft for everything except Ark. Early adoption of regular deck parks could increase these numbers.

The 1938/39 carrier planning saw a need for 3 at home. This reduced to 2 as a minimum in 1940. These were to be the Illustrious class (hangar capacity 33).

The light carrier programme of 1942 was triggered by war experience. Even in the original plans none would have been at sea before mid-1944. Without that experience off Norway in 1940 and then Crete in 1941 they don't happen.

In assessing the Japanese Carrier fleet you are assuming things happen as historical and that there was perfect knowledge of the enemy.

Agreed the Shokakus would complete in 1941 as historical. But little was known about these ships with Allied intelligence considering them as little more than improved Hiryus until into the 1942 carrier battles. Only then does the data start to change. And what about the "shadow" carriers? AFAIK none of the Allies knew about those plans. Zuiho converted 1940, Shoho converted 1941. Junyo & Hiyo were laid down as merchants and acquired in Oct 1940 (officially Feb 1941) for conversion, completing mid-1942.

How does Britain plan for tackling things it had no knowledge of and which the Japanese worked hard to conceal. And with a more peaceful world generally in 1939-41 do they feel so threatened as to feel the need to trigger those plans quite so early?

More butterflies.

Without war in Europe there is no guarantee that Vanguard would be built. The DNC considered her an inefficient design due to 4 turret layout affecting the armour layout. Even the Admiralty were not that keen on it. It was forced on them by events and the prospect obtaining a new Battleship sooner than another Lion with war on the immediate horizon, but only by about 6-12 months. Manufacturing capacity in terms of guns and turrets would have allowed an extra Lion in her place in the 1940 Programme. And modern 16" trumps WW1 vintage 15" any day of the week.

As for the Lions ordered under the 1938 Programme, estimated completion in Aug 1942 gives 42 months from date of order, which is also the timescale set out in John Brown's unsuccessful tender in Jan 1939. But by July when they tendered for the 1939 ship Conqueror, build time was estimated at 52 months. So the second pair of Lions would not be expected to appear until early 1944. And that assumes everything went to plan and all delivery schedules for guns, turrets and armour which were contracted separately by the Admiralty were met. And assuming that held true for the third pair then they wouldn't complete until late 1944, rather than early 1944 as I suggested in my last post.

So against that increase in build time for Conqueror, getting Vanguard in 36 months seems highly optimistic, especially as I noted the H&W gun pits needed reactivated.