WW2 What If?

[Wezil]

Since you seem to enjoy these discussions DF, I have another "what if" if you are interested.

I'm not much interested in arguing it out but I am curious to read your thoughts on the scenario.

[David Floyd]

Sure, I'm all for it.

[Wezil]

Sorry for the delay. Life intervened again.

I recently watched Tora! Tora! Tora! again...

What if the US carriers were at Pearl when the Japanese attacked? Everything else equal.

I'm sure you alt history types have pondered this before.

[Solomwi]

I don't think it makes a difference in the long run, because of the Essex effect. While the Japanese would have been able to accomplish more in the Pacific than they actually did, and America's "comeback" would have been more difficult as a result, they wouldn't have been able to seriously alter the shipbuilding schedule on the West Coast. As overwhelmingly superior as the Big Blue Fleet was after 1943, I don't think the loss of the initial carriers, or the survival of the Japanese carriers they destroyed in 1942-3, would have altered that balance to the point that it favored Japan. In addition, the American admirals, particularly King, understood and acted on the implications of Mahan on the Pacific War better than the Japanese admirals: destroy the enemy fleet (in this case the carriers) first, and you can do whatever you want after that.

The one caveat I'd throw out is that, with a decimated fleet not even able to put a carrier afloat for a long stretch, MacArthur may have been able to leverage his influence to do even more damage to American Pacific strategy than he actually did. If MacArthur had been in complete control of Pacific strategy, whatever carriers were put to sea would have been basically mobile artillery platforms supporting unnecessary ground operations along the Southwest Pacific approach. That would have left them exposed to Japanese carriers without the ability to hit back, a potentially disastrous situation when the proper top strategic goal is destruction of the enemy fleet.

[David Floyd]

What if the US carriers were at Pearl when the Japanese attacked? Everything else equal.

Well, going from memory, the only carriers in the Pacific at the time were Enterprise, Lexington, and Saratoga. Yorktown was in the Atlantic, Wasp and Hornet had not yet been commissioned, and Ranger doesn't count (unable to operate effectively in the Pacific).

OK, so the US loses 3 carriers. Obviously, Yorktown comes over immediately, while Ranger becomes the only carrier available in the Atlantic (this could cause some butterflies but they are outside the scope of this question). Obviously, with only Yorktown available for several months, the US is unable to act offensively, so there are none of the early war raids on Japanese island chains, nor is there a Doolittle Raid, or likely even a Coral Sea battle.

However, once Hornet and Wasp come online, the US has a core of 3 carriers in the Pacific. The IJN may attempt a Midway-style operation, and because of additional losses to US naval aviation (in the long run, the air groups and pilots from Enterprise, Lex, and Sara are actually more important than the carriers themselves), they may even win. Hard to gauge, really. The point is, though, that the Japanese are incapable of finishing the war. They cannot invade either Australia or Hawaii - and even if they could, the war still wouldn't be over. The war may drag on a bit longer, but it is ultimately a foregone conclusion. The Japanese can neither achieve victory nor force peace, so it doesn't matter how many ships they sink early in the war.

Solomwi,

I mostly agree with your analysis, with two minor caveats. First, what exactly could Japan have accomplished additionally, given their manpower and logistics constraints, that would have been meaningful? Secondly, keep in mind that while MacArthur might have gained additional influence, there is little chance he would have been named CinC-Pacific, or anything of the sort. Admiral King, and to a lesser extent, Admiral Leahy, would have been willing to resign before seeing that, and while General Marshall would support the Army up to a point, he would not have allowed such a scenario among the JCS over MacArthur's ego. Marshall and FDR would probably have allowed Mac additional leeway and power, but would have slapped him down over the total control that he wanted (similar to how the pair of them effectively slapped down Montgomery in the ETO).

[BlackCat]

To follow up on Wezil's "what if" - what if the japanese knock out midway and occupy both that and hawaii ?

[David Floyd]

The Japanese can't occupy Hawaii. They have neither the available troop lift nor the logistics to supply and sustain such an invasion. As for Midway, they could probably occupy it given a successful naval battle - but then again, maybe not, given the beefed up defense of Midway and the fact that a much weaker and less prepared Wake Island repelled invasion the first time around. Additionally, Midway is within range of US heavy bombers from Hawaii, which can support the ground defense at will and harass the IJN around the island.

Midway can - PROBABLY - be taken. But not resupplied/maintained. Taking Hawaii is beyond the realm of the possible - it is on the order of a successful Sea Lion. In other words, it would require supernatural intervention to even have a chance.

[BlackCat]

The Japanese can't occupy Hawaii. They have neither the available troop lift nor the logistics to supply and sustain such an invasion.

Why not ? They have total air superiority so the landing and occupaion could be done without problems. US navy has to operate from the west coast, so won't be able to do anything serious in blockading Hawaii.

About nesscecary troops - well, if that had been a part of the attack, then they would have been there. The real problem for them would be if they could deploy sufficient number of air units.

[David Floyd]

By the way, at the time of Pearl Harbor, the following is the approximate force structure available to defend the HI:

Two Marine Defense Battalions (3rd & 4th), two U.S. Army infantry Divisions (24th & 25th) less the 299th Battalion that was detached to the other Islands, four coastal artillery regiments, four AAA regiments (3", 40mm, 20mm, .50 cal), plus the Hawaiian NG units (as well as the rest of the military force on the islands, including the AAF ground elements, with rifles and the Honolulu cops). Call it 15,000 trained men (24th/25th ID were understrength at the time) fighting from prepared positions or in positional defenses that they were trained to defend, and an addtional 15-20K fighting from scratch positions (with roughly half of these having a reasonable chance of hitting something with their rifle).

That was the MINIMUM force that defended Hawaii. And there is no way that Japan could project enough power to overcome that MINIMUM force, much less the additional forces rushed to Hawaii after Pearl Harbor. Think about it - Japan couldn't even ship more than around 8000 men at one time to Guadalcanal. How are they going to ship the necessary 4-6 divisions to Hawaii? And for that matter, where do such ground forces come from? The IJA certainly wasn't withdrawing them from China just so the IJN could go half-cocked after Hawaii.

[BlackCat]

Air superiority.

Edit: And massive arty from naval units - US did this on occation

[David Floyd]

Why not ? They have total air superiority so the landing and occupaion could be done without problems. US navy has to operate from the west coast, so won't be able to do anything serious in blockading Hawaii.

Umm, what? From where is the IJN resupplied? You do know, I hope, that the reasons the Kido Butai was unable to launch a 3rd strike on 12/7/41 was essentially that a)they were too low on fuel, b)US submarines were in the area, and c)US AAA was up to speed and incredibly potent? None of these conditions would have been minimized at any point after Pearl Harbor, and in fact such conditions would have been worse. The IJN - and in fact, no navy up to that point - had developed the fleet train doctrine necessary to operate that far from friendly bases. The USN was the first navy in the world able to conduct operations on the scale of Okinawa, an operation which required probably LESS resources than the IJN would have needed to successfully invade Hawaii.

About nesscecary troops - well, if that had been a part of the attack, then they would have been there. The real problem for them would be if they could deploy sufficient number of air units.

No, the problem was the availability of ground troops and the availability of shipping. Everything the IJN did was on a shoestring. They simply did NOT have the available manpower or logistics to mount a peacetime exercise against Hawaii, much less a wartime operation.

[David Floyd]

Air superiority.

So what? The IJN was designed to sink enemy ships, not conduct CAS operations. It was the USAAF and RAF that perfected CAS later in the war. Also, the IJN air arm was a finite resource that was measurably depleted with every plane shot down and pilot lost. They can't just ship in a new carrier air wing every 3 weeks. They didn't have the trained pilots.

Also, the IJN had absolutely abysmal ASW performance throughout the war. Even facing US submarines carrying torpedoes with a 30% success rate, every single carrier the IJN keeps around Hawaii to maintain "air superiority" is going to be sunk in the long run.

[David Floyd]

Edit: And massive arty from naval units - US did this on occation

Yes, and the US was consistently shocked to find that shore bombardments did much less to suppress enemy defenses than they thought. Read up on, for instance, the invasion of Peleliu. Or for that matter, Operation Overlord and Omaha Beach.

[BlackCat]

Umm, what? From where is the IJN resupplied? You do know, I hope, that the reasons the Kido Butai was unable to launch a 3rd strike on 12/7/41 was essentially that a)they were too low on fuel, b)US submarines were in the area, and c)US AAA was up to speed and incredibly potent? None of these conditions would have been minimized at any point after Pearl Harbor, and in fact such conditions would have been worse. The IJN - and in fact, no navy up to that point - had developed the fleet train doctrine necessary to operate that far from friendly bases. The USN was the first navy in the world able to conduct operations on the scale of Okinawa, an operation which required probably LESS resources than the IJN would have needed to successfully invade Hawaii.

No, I haven't heard anything about they were short of fuel (please post links to evidence), neither have I ever heard any evidence of heavy US submarine activity, and last US AAA was not a question and certainly not why the third strike wasn't sent.

No, the problem was the availability of ground troops and the availability of shipping. Everything the IJN did was on a shoestring. They simply did NOT have the available manpower or logistics to mount a peacetime exercise against Hawaii, much less a wartime operation.

Why not ? Considering what they deployed on a large number of islands, they could have sent them to hawaii for better use.

[Riesstiu IV]

What if, on the eve of the Barbarossa Campaign, Hitler converted to Judaism?