TLDR - A LOT of carriers are going to get sunk. USN and RN are in for a kicking ....but the IJN 1st carrier group won't be able recover losses even if it prevails...but it probably would just edge out the Battle but it will probably be a Pyrrhic victory. . Probably.....Here's why.
Great stuff. Fascinating side show that Thailand is turning into ..and there is clearly going to be some carrier action coming soon. On paper Allies look a LOT stronger. No US Carriers lost so far and RN contributing 3 fleet carriers too. Real life they smashed Japanese at Midway so this time it will be even easier ...right? Wrong.
Question is Will Ark Royal be doomed as OTL? She's got a bigger air arm and experienced crew as UK's first real Fleet carrier but it was a steep design curve in the ten years since she was built and she has some flaws compared with the more rugged Illustrious class . Crucially after "lucky" Ark Royal sank OTL - 6 months before this timeline - the investigation (and court martial of her captain for abandoning ship too early) led to more damage control training AND installation of back up power for damage control in Lusty and her sisters. That hasn't happened here. . Which means the damage control lessons have not been learnt. The legendary hard to sink armoured British Carriers are certainly much more capable of taking a punch than the Japanese per my previous comments.. but not as rugged here as ITTL without the lessons learnt from Ark Royal sinking.
Mid '42 is an interesting transistion period for the RN Carriers. They are coming out in real numbers now and whilst much smaller capacity than Japanese or American , they are fundamentally sturdier fighting ships, better suited for dealing with trouble from nearby coasts than pure open seas all air batles but also ONLY focused on naval warfare. They do lack punch in both quantiry and quality of aircraft ....except at night. By '42 the Swordfish stringbags are replaced by better (not by much) Albacores. Still slow Bi-planes but sturdy and fine all weather / night / day Torpedo bombers ...... as long as there are Zero Zeros around.....Albacores were really only used for a brief time in 42/43 before Barracuda started replacing them. What the Albacore does have , and whilst not on every version, is the second gen surface radar, ASV II primarily used for anti sub work...but also great for finding japanese carriers. They are the only carrier plane in the Pacific theatre with surface radar. We'll come back to that though.
For Aircover Thach and his weave aren't yet a thing. There will be no Turkey shoot. And again ITTL , the USN haven't met the IJN at sea at all yet so really don't even know how much better the Zero is or how to exploits it's flaws. RN and USN both now have F-4 fighter and whilst the Yanks are going to be rightly dissatified vs.the superior Zero (or will be when they meet) , RN FAA fighter pilots must be delighted not be in the Fulmar -( an aircraft that gets a bad rep but was not a modern fighter by 41, let alone 42 but it was dependable, all weather and long (ish) range) .
So here's my totally arbitary summary. US in OTL has just lost USS Lexington. Here it hasn't. It therefore has Enterprise, Hornet, Yorktown, Lexington, Saratoga, Wasp all in the Pacific ITTL. BUT unlike IJN doctrine they tended not to all work together at once and they are going to be stretched all over the Pacific. Of those 6 , only really Big E, Yorktown Saratoga and Hornet are modern full fleet carriers, Lexington was big and had a full air arm but an even earlier design than Ark Royal and long in the tooth . She was sunk OTL due to her innate poorer handling than Yorktown and similar Aviation fuel storage design flaws that the Japanese employed (but no longer other US Carriers or RNby "42) , she also had one single large hanger and only 2 elevators so could not deploy / retrieve as quickly as later designs. Wasp was a cut down treaty version of Yorktown. Think of it more as a big Escort carrier than full fleet (even by 1942 standards). We can assume Ranger stays in Atlantic as no reason to believe U boat menace has gone.
On the Allied side for a "Midway style make or break High NoonNaval showdown with Japan" you have realistically probably 3 UK and 2 to 4 (max) (with intel warning) US fleet carriers.
On the Japanese , with no Indian Ocean raid and no Coral Sea then the full six of the 1st Carrier group - Akagi, Kaga, Sōryū, Hiryū, Shōkaku, and Zuikaku. It's also got a couple of former old fleet carriers but they don't add that much eg. Shoho was working with them at Coral Sea in 42 in May and was sunk OTL ( The original "Scratch one (small) Flat top") so might be there too. So pretty even in ship numbers. Not so in aircraft.
If we are playing Top Trumps at this stage then IJN wins hands down on Aircraft quality, weapons and pilot readiness training. It has also been operating together. The Carriers worked in pairs (even being designed as such with Akagi and Hiryu being built so that the Islands were on opposite sides, odd and not repeated after but it was thought at the time it would give better performance operating closely together). The best two Japanese carriers, by far, were it's newest Shokaku and Zuikaku. They were BIG . Bigger even than Yorktown and "Big E" , and almost twice the displacement of Akagi/Hiryu. They only carried a few more aircraft -70 vs around 60 on Hiryu class depending on the mix, but more spares aand stores. Whislt still fragile due to the AV Gas situation , they were the least "glass jawed". Shokaku did survive, just, multiple hits in Coral Sea and limped home. That's because most of the size / weght increase came from ....armour... ok still floating molotov cocktails as they kept the Aviation fuel sloshing around in main hull BUT something at least. Crucially their hangers were a little bigger though - and it meant Kates didn't have to be folded ie much faster to deploy and reserve planes were ready / arming was faster etc. HERE'S THE PART YOU PROBABLY DIDN'T KNOW - They weren't at Midway. That's right , Japan's , by far two best carriers were not at Midway. Why? Cos they had been fighting Pearl harbor/ Ceylon/ Coral Sea for six months non stop, Shokaku had taken damage at Coral Sea and on the Journey back home .They had both lost a lot of pilots (Zuikaku especially) So , being they operated in pairs (but oddly pilots never transfered ships) they were both kept in Yokohama instead of going to Midway. Now rational people might have thought - er why not just put Shokaku's planes and crew on her exact sister ship Zuikaku and send her with them? Why not indeed..except ..dunno. Cockiness? Paired training? Inflexibility? Sense of Ship "Honour". I betcha Yamamoto wished he had. I bet as he looked out the window of his doomed plane being straffed by P-38s he also wished he'd pushed Nagumo overboard after lunch one Sunday back in about 1940 and also been a bit less sure of himself regards Japanese Naval codes beind unreadable but there you go. Contrast that sort of rigid , oh sure I could take my best carrier with me to what I expect will be a the largest carrier battle in history .... but it's a bit too much paperwork vs. the desperate but battle saving efforts to repair Yorktown and get her into the fight at Midway from the can do Americans.
BUT ITTL - they haven't been eroded down or damaged yet. So it's the full six. And the extra 2 (vs Midway) are the best , bringing another approx 150 Planes to the 250 or so that Japan had at Midway. So 400 Planes. Better ones. Better fighters. Better trained veteran pilots, torpedoes that actually worked and most crew who have even ITTL seen some action - all six carriers took part in Pearl Harbor Attack.
Now lets play out some scenarios.
If it is just the British... well that's actually the best/ worse case scenario for the Allies.
RN / IJN - Open Seas DAY - Japanese Tactical and Strategic Victory
Worst , worst possible case for Allies. If it's in open seas - say East of Phillipines / Borneo / NE of Indonesia - by day then you've got 60 ish aircraft from Ark Royal and about another 70 TOTAL from the other two. 150 Total vs 400 much better planes ( in every department with 3 types - Zero(fighter) Kate (torpedo) Val (dive bomber) vs Wildcat AKA Martlet (fighter) and Albacore (Torpedo - yes it could sort of dive bomb but not really - marginally better than Biggles chucking a Hand Grenade out of a Sopwith Camel ) 6 targets vs 3.(or 6+1 vs 3+1 if Shoho and Hermes come along ) . Sure 2 of the RN are tough as nails and whilst they can take some hits for sure and steam on..they can't conduct full flight operations instantly after getting their decks bombed so you quickly lose a 1/3 od your decks. And 1/2 your planes are in the most vulnerable carrier. In the corner for the British is the second gen Radar for the ships, AND Radar on the Albacores. So they can find the Japanese carriers...but just in time to be blown out of the sky by Zero CAP. And they will be. See the German dash through the channel when Bi-Planes take on ships that have modern fighter CAP, and that wasn't even that well coordinated by Kreigsmarine and Luftwaffe.*. For all of the Swordfish's many accomplishments, none were achieved when the targets had good fighter cover. And likewise RN get about 20 mins more warning of incoming attack, which is helpful but only to to put on clean non brown shorts if you see you are going to totally overwhelmed by 400 planes coming at you. However an operational advantge RN have is that they DON'T practice as a seperate carier only group. At a minium PoW and maybe Repulse (both can keep up) are going to be there ITTL and absorb a lot of fire. By May '42 PoW (at this stage the most powerful Battleship in the Pacific..yes yes Yamato but really it was shit) is going to have her AA radar control working this time. Still by Day there is only going to be one winner. Maybe Lusty can limp home and perhaps somehow an Albacore gets through to hit one of the more flammable IJN Carriers. Afer that though it's batton down the hatches in Singapore as the balance of power at sea will swing to IJN for at least a year denying Allies a lot of quicker war winning options.
Ultimately it all depends on who baits whom. Yamamoto's style we know is to pull a Pearl/Ceylon/Midway type attack in hope of baiting enemy force out. If he does that he won't get this scenario.. On the other hand if a cocky RN/USN go to sea hoping to pull out 1 or 2 Japanese Carriers piecemeal and that Radar alone will give them an advantage they could easily get caught by 6+ Japanese carriers.
* "Herman, Ja, It's Karl calling. Yeah, I'm sorry. Yes. Yes. I shouldn't have called you a pompous fat drug addict in front of the Fuhrer. Twice. Look could you do me a favour and have some fighters flying arond over Brittany say next Wednesday morning.? no not Britain ...the French coast, it's next to England, you know in that big canal in between where your pilots keep swimming ... Ok Ok , bit low. Sorry again. OK great...but Hmm, have you anything better? Maybe those shiny new 190s? No? Ok Ok, just send something , whatever you have and tell them not to shoot at any big grey boats with giant Swatikas on the deck...Danke. Oh and say hi to your lovely wife".
RN / IJN - More inland / Land support DAY - IJN Tactical Victory
Mostly this gets better for RN. Depends if it is off coast of Indo Chine ( lots of extra land based IJN planes that OTL sank PoW) but if anywhere close to Singapore then at least there is more fighter cover. Still it won't be enough. IJN will take more damage but RN still screwed. It might be able to run away under fighter cover.
RN/ IJN - Anywhere (that is Open seas or close to Land support) / NIGHT - Allied Tactical and Strategic victory
This is the single best scenario for the Allies. Even better than if 3 or 4 US fleet carriers are with them (see below for why). It's quite simply totally one sided. IJN have no Radar worth a damn. Not on their Carriers and certainly not in each squadron of torpedo bombers. RN still struggles in numbers - even 40 to 50 Albacores aren't going to be enough to hit and sink 6 IJN carriers...but hit some they will. And be gone.. vanishing in the night...slowly....... spooky!! IJN will lose a chunk or have damaged beyond function its most powerful group for little RN loss. See Scharnhorst vs Duke of York or Italian Cruisers vs Warspite. Best of all the RN knows this and whilst US Intel not perfect., it is prety good and if they get good warning then they can time it so they will be in operational range come Dusk. That's not wishful thinking, it was what Cunningham tried to pull off with far fewer numbers in Indian Ocean OTL It will be a scenario the British want and will do everything to try and make happen. IJN has good surface night fighting but can't conduct carrier operations. in the dark. It will lose multilpe carriers or have them damaged beyond operational use if RN in range at night.
RN/USN Night - anywhere - limited Allied tactical victory.
Here's the issue. USN like IJN doesn't do night operations. Yes they have some Radar on the carrier but it's pretty limited in May '42 and nothing on any planes. OTL , like at Coral Sea in May 42, they and IJN would both stop fighting in the evenig, fly home, try not to accidentally land on the enemy's deck (oh that nearly happened) , have a nice cup of cocoa, read bedtime stories and get up fresh for death at Dawn. Having the USN with the RN at night is actually going to be a liability because it limits the flexibility of the RN group operations and it's a bit of a lowest common denoninator.
UNLESS - RN hits at night with USN ready at Dawn to deliver more powerful day blow against damaged IJN. Very hard to coordinate but one of the few viable ways the IJN power could really be really totally smashed for little loss.. Have to roll a lot of Hard Sixs...but then they did at Midway.
RN/ US vs IJN - Day / Open Seas - IJN Tactical victory , Strategic Win Allies
This is best for IJN in terms of how much tonnage they will sink BUT it will come at a cost. There's no game of Nagumo Rock Paper Scissors .ohh ohh lets change to land bombs , no ship bombs, no land bombs. So the IJN will be all tooled up for Ship combat. In a close to shore engagement then expect Nagumo to his usual hedge it and indecisive usual self ( 3 TIMES he did this! Pearl, Ceylon, Midway - either holding back or hedging attack waves or changing his mind at last minute delaying everything)
But it's going to be REALLY Messy. This scenario numbers are in parity. But Japanese are much better coordinated than the Brits / Yanks who are just thrown together - (look up USS Robin and how after a bit of combined work RN/ USN realised that USS Saratoga with more space and bigger elevators/ catapults was much better at launching Bombers whilst HMS Victorious had RAF style dedicated CAP control room and radio channels ...but it took a while to figure out. at least that's the ofcial story. USN fighter pilots probably just wanted to be based on a ship rolling in daily free Rum and not Dry) The IJN will hit hard. and all 3 plane types and weapons are best in '42. USN Torpedos will be rubbish and RN Tortoise bomber , sorry Torpedo bombers shot down at leisure. IJN CAP will be larger and capable of downing a lot more than at Midway. BUT USN Douglas Dive bomber will no doubt prove their worth. It will be a slugfest but I suspect even with British Radar and US Intel lAllies lose several carriers and not achieve the 100% success of Midway. (as Meatloaf sang - 4 out of 4 ain't bad) . Still if even 2 to 3 IJN carriers are severly damaged or sunk , even at a much higher cost than OTL , it achieves the same strategic victory as Midway did - the end of the IJN Carrier fleet as the most powerful single weapon at sea. US and RN can and will rebuild faster (even the UK alone built more carriers than Japan in the war , let alone 24 Essex Carriers being laid down by Uncle Sam) .
RN/ US vs IJN - Day - Land support close by
As above but bit better for Allies..probably. More chance of Nagumo messing up, more chance to coordinate with Radar land support but not much better. Midway land based aircraft achieved nothing at Midway but distraction (that was valuable mind you against Nagumo) and RAF has Hurricanes not Spitfires out of Singapore/ Thailand. Still anything helps and some B-17s pulling away Zeros would be worth it.
All the anove only applies if it happens Summer ' 42. The longer the IJN wait, the worse it gets for them. USN/RN will learn to coordinate and that means better CAP/ Radar search?/Better planes/ More ships. This is peak IJN and every day that goes by they get relatively worse.
Also - all a sideshow anyway. It's MAY 1942 Allan -- whats happening in Kharkov???
NOTE: Visitors to London may have noticed a tall structure in the middle with a statue of a heavily disabled man on top, that, when not covered in Pigeon Poop, is testament to leadership being quite an important factor in Naval Warfare. Here it is mostly advantage Allies. OTL showed that with Halsey, Spruance, Nimitz et al .. the USN leadership had depth and took initiative. IJN did not have that. Too centralised , which might have been ok if not centralised around someone who didnt prove time and time to be indecisive. Add Cunnngham to the plus column for RN. Even Phillips .. history been a bit unkind but no-one knew the Japanese had massive numbers of long range torpedo bombers and before PoW/ Repulse went down they did put up one hell of a fight. Only downside to Allied leadership is coordination - King hated the Brits and OTL didn't want them anywhere near the Pacific even when he was forced to borrow a fleet carrier ( USS Robin , ahem HMS Victorious) . ITTL with Singapore intact and Brits doing so well they will probably take the lead in '42 or at least be equal partners ... as it goes on into 43 USN numbers will dictate overwise.
PS - super sorry about typos but I dont' care. However Reknown confusion is simply inexcusable and ..... Repulsive. I have corrected. I stand in the corner of obscure nautical knowledge shame.