Rn vs IJN

The changes I listed above were some of what the Admiralty was considering at the time of the construction of the Ark Royal for the follow on units. Apparently there was a debate as to whether they should build a second hull nearly identical to the Ark Royal, and then switch to the improved hulls, or accept a years delay while they completed the design for the improved hulls. In the memo they referred to the Ark Royal in terms such as "When she is completed she will have . . .", etc. I do not remember the date on the memo (if there was one - it was in a hardcover book that I ran across a long time ago), but it was from when she was still building.

As you mention above, at the time of construction the catapults(accelerators) were only rated for 8000 lbs at 56 knots, and in 1934-35 the Admiralty already knew that aircraft were going to get bigger so the plan was to increase the loads (the load at v was not specified in the outline I saw).

I do not think the intent was to increase the power of the machinery so much as to use the newer higher pressure boilers, and maybe turbines as well - so more for fuel economy, and maintenance savings (maybe weight and space to a degree?).

The plan for the follow on hulls was for crash barriers as in plural, so 2 or more.

Apparently they were not completely happy with the angles of fire for the 4.5" mounts at the time of the memo, and wanted more cross deck AA capability (not low angle). I have never been able to find what the actual arrangements were intended to be. Maybe the final layout of the 4.5" mounts on the Ark Royal was the result of the note in the outline? I know they tried to improve the angles in the Illustrious class but I do not know if they were any happier with the arrangements as far as arcs of fire go.

As to what the aircraft complement would have been? When I look at the square footage of the hangars in terms of rectangles that can accommodate an Albacore it seems like there is room for at least 64 between the two hangars - if you do not have to worry about the amidships elevator(lift). They would probably have had to rearrange the fire curtains and such. Again the memo did not detail the changes in the elevators(lifts) aside from the use of a single platform instead of the double platform on the Ark Royal's elevators(lifts) so I do not know how this would have affected aircraft numbers.

The outriggers would have added at least 5 aircraft to the available stowage, though not in really bad weather, so what they would have decided I do not know. I think outriggers were already in use or being trialled on the Eagle?

RCAFson said:

The IJN entered the war in Dec 1941, not Sept 1939.

Click to expand...

It was not claimed otherwise. Did you really gather that it had been?

Wild_Bill_Kelso said:

Put Germany out of the war (or focusing on Russia first) and France and Italy cancel each other out. I don't think it changes a thing.

Click to expand...

It actually changes quite a number of things.
Germany attacks Russia in 1940?
Supermarine and Shorts don't get bombed. Changing production and development.
No BoB, changes RAF inventory by hundreds (over 1000?) aircraft by 1941?
Does Lend Lease even happen?

France gets their Tomahawks, Marylands, A-20s and Vultee Vengence dive bombers? and other odds and sods but the British don't get to inherit any of them.

If Germany goes east in 1940 does Italy even join WW II? They only jumped on France when it looked like France was already beaten.
Maybe they still Attack Greece in Fall of 1940 and hope that France stays Neutral?

We can keep going on this but the changes to British force numbers and losses not taken are substantial.

We also have the Flip side, RN doesn't learn anywhere near as much about AA gun use. Or ship to ship. Does Germany start/keep up U-boat attacks or leave Britain and France alone as France stays on it's side of the Rhine

Wild_Bill_Kelso said:

What we can learn is that the RN ships air aircraft were unable to cope with the IJN equivalent. We don't have to write an alternative reality screenplay to do that. Just sweeping away the BS which crops up here routinely.

Click to expand...

We have not learned that the RN ships were unable to cope with IJN equivalent. There were too few engagements to get a good evaluation during Dec 1941 and early 1942.
We have no assessment of the RN subs against the Japanese at this time. Nor do we have much information of Japanese subs vs the RN. The whole anti-sub thing is up for grabs.
Destroyers are actually not good anti-sub ships. When the British converted old ones to escort use they took off guns and torpedo tubes to fit more depth chargers and depth charge launchers. You also can't use asdic/sonar much over 15kts (ship makes too much noise) so the high speed is not that much of an advantage.
14-18 depth charges per Japanese destroyer as originally fitted was nowhere near enough. Many of the Japanese Destroyers were fitted with 36 depth charges later in the war. It was not enough.

Shortround6 said:

It actually changes quite a number of things.
Germany attacks Russia in 1940?
Supermarine and Shorts don't get bombed. Changing production and development.
No BoB, changes RAF inventory by hundreds (over 1000?) aircraft by 1941?
Does Lend Lease even happen?

France gets their Tomahawks, Marylands, A-20s and Vultee Vengence dive bombers? and other odds and sods but the British don't get to inherit any of them.

If Germany goes east in 1940 does Italy even join WW II? They only jumped on France when it looked like France was already beaten.
Maybe they still Attack Greece in Fall of 1940 and hope that France stays Neutral?

Click to expand...

Honestly, a France vs Italy (maybe with a little German support) in 1940 or 1941 "What If" could be very interesting I think....

Shortround6 said:

We can keep going on this but the changes to British force numbers and losses not taken are substantial.

We also have the Flip side, RN doesn't learn anywhere near as much about AA gun use. Or ship to ship. Does Germany start/keep up U-boat attacks or leave Britain and France alone as France stays on it's side of the Rhine

We have not learned that the RN ships were unable to cope with IJN equivalent. There were too few engagements to get a good evaluation during Dec 1941 and early 1942.
We have no assessment of the RN subs against the Japanese at this time. Nor do we have much information of Japanese subs vs the RN. The whole anti-sub thing is up for grabs.
Destroyers are actually not good anti-sub ships. When the British converted old ones to escort use they took off guns and torpedo tubes to fit more depth chargers and depth charge launchers. You also can't use asdic/sonar much over 15kts (ship makes too much noise) so the high speed is not that much of an advantage.
14-18 depth charges per Japanese destroyer as originally fitted was nowhere near enough. Many of the Japanese Destroyers were fitted with 36 depth charges later in the war. It was not enough.

Click to expand...

Again, all interesting stuff, but I really don't think 15, or 20, or 50 British submarines are going to turn the tide of a major Pacific conflict all their own, and as soon as the Japanese take Malaya and Singapore, Hong Kong and Burma (which I believe they certainly would do) the subs are going to lack a viable Pacific base. They might do some damage before they go, even quite serious damage, but I don't think the Japanese are helpless against them, and I don't think they offer enough capability on their own. Their bases will be vulnerable to IJN bombing and heavy shelling.

The IJN may have to play some catch up in ASW, but it's easier to add sonar and more depth-charges to destroyers and light cruisers than it is to design, manufacture and deploy viable carrier based aircraft. IMO.

More domestic planes vs. no Lend Lease planes probably doesn't help that much IMO, though it (Spitfires) might shore up the defense of some of these bases, they will also lose the small amount of longer (i.e. medium) range fighter support they would have which curtails their strike capability. I don't think it shores it up enough, especially given the initial surprise impact of the Japanese fighters.

Shortround6 said:

We have not learned that the RN ships were unable to cope with IJN equivalent. There were too few engagements to get a good evaluation during Dec 1941 and early 1942.

Click to expand...

That is a fair point, though there were a couple of clashes, the sample is very small and mixed in with Allied ships. From reading about those battles around Java, clearly both the IJN and RN had some room to grow vis a vis training, kit, standardized tactics and so on, though the IJN did prevail, decisively. But you are right we can't say for sure which side is most likely to win on that basis.

We really have to look at the kit, which to me was fairly decisive again in favor of the IJN, at least early on.

The British advantage in radar would surely be a factor at night, but enough to overcome torpedoes with twice the range and 30% more speed, plus much better naval optics? I kind of doubt it.

The IJN also had a fleet of very good flying boats and seaplanes, as well as very long ranged land based bombers (G3M, IJA Ki-21 etc.) they could have probably used much more for ASW, and would have if the US torpedoes had worked.

Wild_Bill_Kelso said:

The British advantage in radar would surely be a factor at night, but enough to overcome torpedoes with twice the range and 30% more speed, plus much better naval optics? I kind of doubt it.

Click to expand...

If the Brits have (and believe) better intel on IJN weapons and doctrine they may be better prepared.

Admiral Beez said:

If the Brits have (and believe) better intel on IJN weapons and doctrine they may be better prepared.

Click to expand...

Sure - not at all impossible but that would get us back into possible new variations and designs

Wild_Bill_Kelso said:

We really have to look at the kit, which to me was fairly decisive again in favor of the IJN, at least early on.

Click to expand...

Depends on the kit.
British AA was not good, Japanese AA was worse.
British may have an edge in surface guns, still looking. British have small edge in Destroyer guns.
Many British destroyers had one pair of K guns (depth charge launchers) which allowed for a 4 charge diamond pattern at the start of the war. One off the stern, the two launchers firing of the sides and followed by the 4th charge off the stern. The anti-sub ships soon went to a 7 charge pattern using 4 K guns. The British ended the war with the ability to drop a 14 charge pattern. The "fleet" destroyers could not do that.

Wild_Bill_Kelso said:

The British advantage in radar would surely be a factor at night, but enough to overcome torpedoes with twice the range and 30% more speed, plus much better naval optics? I kind of doubt it.

Click to expand...

radar also helps in poor visibility, fog/haze/drizzle. The amount of time anybody can actually see 40,000yds is pretty rare. Somewhere in here I posted a drawing and calculated how high above the water you have to be just to see the masts, tops of a ship that is 100 ft above the water. Well less than 40,000yds. You can't shoot at what you can't see. Optics don't let you see over the curve of the earth. So let's look again

Torpedo directors are going to be between 30 and 45 ft above sea level. Best case of 45 feet up gives a range to the horizon of about 14,460yds. You can double that to catch a glimpse of an enemy bridge that is also 45 ft high. Good luck estimating course though unless you can see a bit more of the ship.
The big 8 in gun Japanese cruisers might be able to fire at over 30,000yds. smaller ships????
And you need perfect weather conditions. The Japanese have an advantage, just not quite as much as the range figures suggest.

Go look at the battle reports. What ranges were they actually fired at. British torpedoes were either a few kts faster than American torpedoes or a few thousand yds longer ranged. Also carried a much larger warhead at least early in the war.

Admiral Beez said:

If the Brits have (and believe) better intel on IJN weapons and doctrine they may be better prepared.

Click to expand...

It could take 3-4 years to get a plane into service.

Night fighting did not always depend on good optics. Some navies actual used directors for their search lights. All searchlights pointed at the same target, just flashing around at random looking for something was a great way to make yourself a target.
Star shells were also important.
Depending on navy and the issue of float planes, they sometimes used float planes to drop flares behind the enemy ships to silhouette them.

Somebody may want to ask the Italians how bad the British were at night fighting

Shortround6 said:

It could take 3-4 years to get a plane into service.

Click to expand...

I meant more that British tactics could be modified along the lines of the intel. If the RN knows and appreciates that the IJN has torpedoes capable of 24,000 yards (50 knots) to 44,000 yards (36 knots), then the Brits might take this into account. Same as the A6M, know your enemy and prepare accordingly - though I don't know how a Fulmar squadron leader would prepare his guys.

Admiral Beez said:

I meant more that British tactics could be modified along the lines of the intel. If the RN knows and appreciates that the IJN has torpedoes capable of 24,000 yards (50 knots) to 44,000 yards (36 knots), then the Brits might take this into account. Same as the A6M, know your enemy and prepare accordingly - though I don't know how a Fulmar squadron leader would prepare his guys.

Click to expand...

What the USN knew about the Type 93 Long Lance.

Admiral Beez said:

I meant more that British tactics could be modified along the lines of the intel. Same as the A6M, know your enemy and prepare accordingly - though I don't know how a Fulmar squadron leader would prepare his guys.

Click to expand...

"Jolly good, lads! Grab your ankles, bend over, and kiss your asses goodbye!"

On a slightly more serious note, one has to admire the British approach to near insurmountable odds with deadpan humour and a stiff upper lip.

z42 said:

"Jolly good, lads! Grab your ankles, bend over, and kiss your asses goodbye!"

Click to expand...

Indeed. But the Fulmar has mass and heavy armament. The RN has radar that can help the Fulmars remain at high altitude and then dive upon the Zeros. That's their only chance really.

Here's ChatGtp. Ai seems to assume that all Fulmars carry a rear gunner, which is fact was a rarity. I've bolded in Red below where I think ChatGpt may be optimistic.

What are the best tactics for the Fairey Fulmar to beat the A6M Zero?

The Fairey Fulmar versus the A6M Zero, huh? That's a matchup from the history books! The Fulmar was a sturdy but not-so-agile British carrier-based fighter, and the Zero was a nimble and highly maneuverable Japanese aircraft. To beat the Zero in a Fulmar, you'd have to use your strengths and exploit the Zero's weaknesses.

1. Altitude Advantage: The Fulmar wasn't the most agile, but it had decent speed and climb rate. Try to gain altitude before engaging the Zero. Boom-and-zoom tactics could work well, where you dive in, take your shots, and then zoom back up before the Zero can turn on you.
2. Teamwork: If possible, engage Zeros in pairs or groups. The Fulmar's rear gunner could provide additional firepower and cover your six while you make attack runs.
3. Hit and Run: The Zero excelled in dogfights, but it had a weakness in terms of durability. Hit the Zero with quick, accurate bursts of fire, and then use your speed to disengage before it can turn the tables.
4. Avoid Turning Battles: The Zero's strength was in its agility and turning ability. Don't get into prolonged turning engagements; use your speed and try to keep the fight on your terms.
5. Know Your Limits: The Fulmar wasn't as nimble, so trying to out-turn a Zero is generally a bad idea. Stay disciplined and stick to hit-and-run tactics.

Remember, tactics can vary depending on the specific conditions of the engagement, so adapt as needed. Good luck, ace!

Shortround6 said:

Depends on the kit.
British AA was not good, Japanese AA was worse.
British may have an edge in surface guns, still looking. British have small edge in Destroyer guns.
Many British destroyers had one pair of K guns (depth charge launchers) which allowed for a 4 charge diamond pattern at the start of the war. One off the stern, the two launchers firing of the sides and followed by the 4th charge off the stern. The anti-sub ships soon went to a 7 charge pattern using 4 K guns. The British ended the war with the ability to drop a 14 charge pattern. The "fleet" destroyers could not do that.

radar also helps in poor visibility, fog/haze/drizzle. The amount of time anybody can actually see 40,000yds is pretty rare. Somewhere in here I posted a drawing and calculated how high above the water you have to be just to see the masts, tops of a ship that is 100 ft above the water. Well less than 40,000yds. You can't shoot at what you can't see. Optics don't let you see over the curve of the earth. So let's look again
View attachment 742051
Torpedo directors are going to be between 30 and 45 ft above sea level. Best case of 45 feet up gives a range to the horizon of about 14,460yds. You can double that to catch a glimpse of an enemy bridge that is also 45 ft high. Good luck estimating course though unless you can see a bit more of the ship.
The big 8 in gun Japanese cruisers might be able to fire at over 30,000yds. smaller ships????
And you need perfect weather conditions. The Japanese have an advantage, just not quite as much as the range figures suggest.

Go look at the battle reports. What ranges were they actually fired at. British torpedoes were either a few kts faster than American torpedoes or a few thousand yds longer ranged. Also carried a much larger warhead at least early in the war.

Click to expand...

Right, but keep in mind, most IJN surface task forces had battleships, battle cruisers, or at least heavy cruisers with them, and many of those had the real high 'pagoda' style superstructures. which were very high for just this exact reason.



The fancy 'big eye' binoculars were mounted way up top there.



Once someone in the fleet knows where the enemy is, they can help direct the torpedo launch. They don't need to spot the masts of the enemy ships either, sometimes just spotting the smoke plumes was enough. And I agree that still won't be at 40,000', it's still probably closer to 20-25,000', sometimes a lot less.

In addition to their excellent binoculars, the IJN also used float plane scouts for spotting enemy aircraft, including at night, and they carried quite a few of them and had some good ones, even early on.

I do also concede that in bad weather i.e. rain, fog etc. (which wasn't unusual particularly in the South Pacific) the British radar would help a great deal.

I just don't know if that alone is enough to make up all the other differences. Also the heavier Japanese warships, CA on up, seemed to be quite good in gunnery. And of course you have the Yamato class.

Shortround6 said:

It could take 3-4 years to get a plane into service.

Night fighting did not always depend on good optics. Some navies actual used directors for their search lights. All searchlights pointed at the same target, just flashing around at random looking for something was a great way to make yourself a target.
Star shells were also important.
Depending on navy and the issue of float planes, they sometimes used float planes to drop flares behind the enemy ships to silhouette them.

Somebody may want to ask the Italians how bad the British were at night fighting

Click to expand...

I never understood why they didn't use something like drones, or just smallish boats with searchlights on them, to spot the enemy ships without highlighting your own... they did also use flares dropped by their E13s and F1Ms etc.

Admiral Beez said:

Indeed. But the Fulmar has mass and heavy armament. The RN has radar that can help the Fulmars remain at high altitude and then dive upon the Zeros. That's their only chance really.

Here's ChatGtp. Ai seems to assume that all Fulmars carry a rear gunner, which is fact was a rarity.

What are the best tactics for the Fairey Fulmar to beat the A6M Zero?

Click to expand...

Bail out, that way at least you deny them the death of your crew (hopefully)

Shortround6 said:

It could take 3-4 years to get a plane into service.

Night fighting did not always depend on good optics. Some navies actual used directors for their search lights. All searchlights pointed at the same target, just flashing around at random looking for something was a great way to make yourself a target.
Star shells were also important.
Depending on navy and the issue of float planes, they sometimes used float planes to drop flares behind the enemy ships to silhouette them.

Somebody may want to ask the Italians how bad the British were at night fighting

Click to expand...

How quick could they get a single seat Fulmar with clipped wings into action?

Wild_Bill_Kelso said:

How quick could they get a single seat Fulmar with clipped wings into action?

Click to expand...

Easy enough to pull out the rear seat. That'll save some weight. Take the Mk.II with the 1350 hp Merlin and four 50 .cal.

Wild_Bill_Kelso said:

How quick could they get a single seat Fulmar with clipped wings into action?

Click to expand...

Longer than it would take to put a folding wing on a Hurricane?