Late 1943 carrier battle

Not really about the OTL late 1943, but in this ATL, somehow IJN managed not to lose any more carriers after Coral Sea, they extended their perimeter a bit more, in the New Hebrides and several other small islands. There have been a sort of stalemate since late 1942, punctured by intense air action in the Southwest Pacific and especially New Guinea. They have lost Midway in 1942 and the Aleutian outposts in spring/summer 1943 (they were too late to catch the invasion fleet). They have carried some damaging commerce raiding operations in the Indian Ocean.

They have taken heavy losses in the air (as OTL they still gave as good as they got) but the carrier groups are still in good shape. Now they are waiting for the inevitable US push.

Conversely the US somehow managed to lose all the pre-war carriers except Saratoga. They couldn't advance toward the New Hebrides and the Solomons or other islands because they didn't had the carriers to support landings and protect against IJN. After those losses they ordered even more Essexes and CVL conversions. But by second half of 1943 they received or receiving 10 new carriers, Essex and Independence class, with more to come. Not to mention scores of CVEs.

So, where is this carrier battle taking place, in the South Pacific or the Central Pacific? Are the US forces trying to advance in the Solomons to isolate Rabaul, or do they go straight for the Central Pacific?
 
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Basically. Thing is, the Japanese can't win, the Americans by this point will really be picking up an edge in both technology and training.
 

CalBear

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So we are looking at 5-6 CV (Sara and 4-5 new Construction), 6-7 CVL, and 20 or so CVE? Effectively the Tarawa invasion force minus Enterprise??

Did the U.S. take Guadalcanal or was that entire engagement butterflied away?

The answer about Guadalcanal is pretty much the key to answering most of the rest of the scenario. If the Allies have secured Guadalcanal, then the engagement is most likely going to happen off Rabaul or in the Solomons. If the 'Canal hasn't happened then the likely engagement will be either in the Gilberts or Marshalls, although Wake is not out of the question.

The IJN has the Kido Butai, intact as it was at Pearl, plus whatever of the light carriers are attached orf are close enough to help. IJN tactics are going to have the Battle Line, excepting whatever is intact of Kongo class, close to Japan, where the "Decisive Battle" was to take place. It is still early enough that the deployment of the heavy units has not be impacted by the fuel situation, so they are not tethered to the South China Sea.

The Japanese will have, depending on how many of the light carriers are with the Kido Butai between 450 and 600 total aircraft. If they haven't suffered the losses at Midway (extremely unlikely, but for the scenario, we can run with it) they also haven't altered their air group compositions to increase fighters, so they have around 140-170 A6M, and roughly equal numbers of both D3A and B5N. The USN will have between 800-900 aircraft (including the CVE) around 650-750 without them.

The U.S. is now 100% Hellcats on the CV & CVL, with Wildcats on the CVE, a mix of SBD & SB2C dive bombers and 100% TBF torpedo bombers. Since the U.S. seems to have suffered close to the same losses as IOTL (again adding in the Enterprise) so each CV carries 36 Hellcats and each CVL has 20-24, so 280-315 Hellcats, ~180-210 dive bombers and the 180-200 TBF, and the CVE will have around 150-175 F4F-4 and a similar number of TBF.

The U.S. has a significant qualitative advantage aircraft for aircraft, a small, but noteworthy advantage in aircraft numbers, including a major advantage in fighter numbers, and demonstrably more battle worthy decks. The U.S. also has an almost unimaginable advantage in both AAA (the IJN having far less reason than IOTL to alter the concept that the carrier AAA is sufficient for self defense, a belief they never really shook even IOTL, and the escorts having very few useful longer range DP guns, especially compared to the masses of 5"/38 on the U.S. fleet) and in radar/fighter direction.

This is another place where the Guadalcanal question becomes important, since it was there that the JNAF really died, but even accepting that IJN pilot losses have been halved, this will wind up like the Turkey Shoot, except with heavier losses for the IJN surface force than Philippine Sea and the likely loss of at least a couple USN CVL (or maybe the poor 'ol torpedo magnet Saratoga). The USN has gotten itself sorted out, the Mark 13 has received around half of its modifications, making it as good of an air dropped torpedo as exists at the time, the IJN has lost even the appearance of having a better fighter, is still flying a dive bomber that was obsolecent in 1942, and still has four carriers made out of spun sugar at the heart of its force, with the same haphazard DC that dogged the Japanese fleet throughout the war.

If the IJN get out with two operable decks and 100 aircraft it had a good day.
 
The US Carrier force celebrates "Meatball Day" named so because of all the kills the fighters have scored up.

:D

And of course Intrepid will somehow suffer torpedo hits, just like OTL.:)
 
Thanks for your very knowledgeable reply CalBear. Ah, pitty is midnight again as i like going on and on about this stuff.

I am just assuming for the purpose of this TL that there have been carrier engagements and IJN carrier strikes after Midway, but somehow despite having ships damaged the IJN lost none (except Ryujo). They do have increased fighter squadrons of 27 Zeros on the large CVs. Conversely i "accelerated" the commission of and extra Essex and Independence by late 1943.

The IJN carriers are Akagi, Kaga, Hiryu, Soryu, Shokaku, Zuikaku, Junyo, Hiyo, Zuiho, Ryuho screened by 7 BB (no Kongos lost), a dozen CA/CL and two dozen destroyers.

Airgroups for the large carriers (Akagi, Kaga and the 'kakus): 27 VF, 27 VB, 18 VT plus couple of VS each.
Airgroups for Hiryu and Soryu: 21 VF, 18 VB, 18 VT plus one or two VS each
Airgroups for Junyo and Hiyo: 24 VF, 18 VB, 9 VT each
Airgroups for Zuiho and Ryuho: 21 VF and 9 VT each.

Most of the VF will be A6M2/3 with an important number of A6M5 being fielded as well. There would probably be a number of D4Y1/Y1-C and B6N1 Tenzans on the larger ships, complementing but not replacing yet D3A2 and B5N2, but the second line carriers are equipped with D3A2 and B5N2 only.

All IJN large carriers would have somewhat increased numbers of 25mm AA, improved damage control, most have radar, and Akagi has 12x 100mm (3.9 in) type 98 AA guns refitted during second half of 1942 (not sure if pushing it here, Akagi was intended to be refitted with apparently 127 mm type 89 guns, but someone suggested why wouldn't they go for the newest and most capable AA gun?)

Ozawa is likely in command (how long can they keep Nagumo anyway).
PS: Oh wait a minute, it might be Yamaguchi, not Ozawa.
 
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CalBear

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Thanks for your very knowledgeable reply CalBear. Ah, pitty is midnight again as i like going on and on about this stuff.

I am just assuming for the purpose of this TL that there have been carrier engagements and IJN carrier strikes after Midway, but somehow despite having ships damaged the IJN lost none (except Ryujo). They do have increased fighter squadrons of 27 Zeros on the large CVs. Conversely i "accelerated" the commission of and extra Essex and Independence by late 1943.

The IJN carriers are Akagi, Kaga, Hiryu, Soryu, Shokaku, Zuikaku, Junyo, Hiyo, Zuiho, Ryuho screened by 7 BB (no Kongos lost), a dozen CA/CL and two dozen destroyers.

Airgroups for the large carriers (Akagi, Kaga and the 'kakus): 27 VF, 27 VB, 18 VT plus couple of VS each.
Airgroups for Hiryu and Soryu: 21 VF, 18 VB, 18 VT plus one or two VS each
Airgroups for Junyo and Hiyo: 24 VF, 18 VB, 9 VT each
Airgroups for Zuiho and Ryuho: 21 VF and 9 VT each.

Most of the VF will be A6M2/3 with an important number of A6M5 being fielded as well. There would probably be a number of D4Y1/Y1-C and B6N1 Tenzans on the larger ships, complementing but not replacing yet D3A2 and B5N2, but the second line carriers are equipped with D3A2 and B5N2 only.

All IJN large carriers would have somewhat increased numbers of 25mm AA, improved damage control, most have radar, and Akagi has 12x 100mm (3.9 in) type 98 AA guns refitted during second half of 1942 (not sure if pushing it here, Akagi was intended to be refitted with apparently 127 mm type 89 guns, but someone suggested why wouldn't they go for the newest and most capable AA gun?)

Ozawa is likely in command (how long can they keep Nagumo anyway).
PS: Oh wait a minute, it might be Yamaguchi, not Ozawa.

The D4Y was a serious problem in development as well as once in the field. It had a number of great features, especially over the D3A, but the chances of them being the main, much less only dive bomber operating from the big decks is minute, and if they were somehow deployed, it would have a major impact on availability (as was the case with all the post 1941 Imperial designs the Atsuta engine had serious reliability issues, mainly related to the actual metals available for construction, eventually the engine was replaced by a Mitsubishi radial, creating the Model 33 but that was well after the scenario date, and the swap created some other insoluble issues, although it had the advantage that it ran more reliably). While the B6N was more reliable, it also suffered several delays in production (one related to an engine swap after only around 130 were completed).

It is strikingly unlikely that the IJN would be able to get these problems straightened out, especially for both aircraft, in the time frame under discussion. It would actually be easier for the USN to have the carrier force fully equipped with Corsairs, than for the IJN to have even partially full decks of Suisei.

The Japanese were also very unlikely to replace the 127mm guns on Akagi with the Type 98 100mm, if for no other reason the relative scarcity of barrels (only 163 were produced during the entire war). It is a minor point, even a dozen addition 100mm are unlikely to have more that incidental impact, but the IJN didn't do things quite that way. Even with the 100mm the train rate (16 degrees a second, compared to the USN 5"38 rate of 25-30 per second)) of the mount makes it a far less capable weapon than its pure ballistics would indicate. The general increase in the 25mm guns is rather like the USN mania for mounting 20mm guns on every available flat space, having the gun there is an improvement over nothing, but that is about the best that can be said for the small caliber weapons.

Regarding the BB screen and the inclusion of the Hiyo class ships - This mean the Kido Butai is now limited to ~25 knots, even under ideal conditions, less if any sort of weather is encountered since that is the top speed of the Hiyos. The battleships are also of minimal use in the AAA escort role, although being as large as they are they might distract some pilots from the carriers, despite the emphasis placed on the mission by the CAG.

Lastly, had Midway not sorted out the way it did, Nagumo would have remained in command of the Kido Butai, unless Yamamoto had been killed, then he might have been part of a general promotion shuffle. Having won at Pearl, Midway, in the IO, and in every other carrier/carrier engagement (in fact the ONLY time the IJN lost a deck in this scenario was when a carrier force went into action without him in overall command of the strike force). He would likely have gotten the aura of invincibility and unfailing luck around him, something that would weld him to the command chair.
 
Also, IMO radar is unlikely to come along, with greater early success it's likely Japan will simply decide they don't need it, and if they do have it, it won't be up to much anyway.
 
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