PC: Attack on Pearl Harbor as an invasion of Hawaii?

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So in other words you are cherrypicking numbers to fit your idea. Again.

Your own source talks about how other personnel were trained in basic infantry roles, and on the defense this is more than adequate. So again, the ACTUAL number of defenders is closer to 45,000. Hell, if the second part is right its actually closer to SIXTY thousand total. Which bumps the needed men from 120ish thousand all the way up to 180,000 for the islands. And yet you still somehow you still think this is a good idea.

Even if you deduct the Hospital Forces as they might be too busy patching people up and can be considered non-combatants you are at 54,000 which means you need 162,000 or so .
 
Even if you deduct the Hospital Forces as they might be too busy patching people up and can be considered non-combatants you are at 54,000 which means you need 162,000 or so .
I have not been working on this like I should have been, instead I get easily distracted and go off and work on something else. :(

OTOH, I have gotten that I will need to do several threads, each dealing with one or more aspects needing to be covered before I can move forward with my posited "Invasion Hawaii" thread.

The threads I know I need right now are:
Japanese Oil reserves, how long they can operate, and how long until partial production can be restored once the SRA can be secured. As it turns out, the Japanese have a big shortfall in tankers, if they were getting the oilfields intact, but not so bad with limited production coming online only months later, like in OTL. I'll be wanting to find out just what kind of production the Japanese managed from the captured oil fields, and when this happened.

Where do the Japanese land in the Hawaiian islands, when, and with how many troops? I want to have them hitting as many places as possible, as soon as possible, as the US defense will never be weaker and less prepared than the second week of Dec 1941, and as many airfields must be captured as they can get, in order to start basing large numbers of land based aircraft on the occupied islands. Do the Japanese have enough aircraft ferries to bring land based planes forward in large numbers? In order to stage land based fighter aircraft into occupied Hawaiian islands, do they need midway, assumes that with drop tanks, the aircraft in question would have the range to make it all the way from forward staging bases, if they can use midway as a fueling stop, as if this is not possible, then midway still has to be taken ASAP, but the only fighters making it to the rest of the Hawaiian islands will have to be carrier fighters or ferried in.

How much shipping is going to have to be earmarked for this operation, and how much do they have to spare, given OTL operations against the UK and the DEI are delayed?
Also, given that the air campaign against the FEAF must go on like OTL, to prevent these forces from being withdrawn and redeployed, how many land based aircraft are going to be available for use in the Hawaiian theater?

Seaplanes, the types, numbers and capabilities.

Basically, if the Japanese are coming to take over, they need to plan to bring everything they can, and keep it in theater as long as the issue is in doubt. This means that the historical raid needs augmented, as the OTL results didn't eliminate US airpower entirely, and I don't see the KB being able to do that at the same time as they are hitting the fleet. The only thing I can think of that could be used in the ATL PH attack is something with the one-way range to bring a large weapon to bear against high value targets with very great accuracy is the H6K configured as a Kamikaze.
 
Japan is in a bit of a Catch 22 situation here. The easiest way to solve the problem is to have Japan build more oilers and supply ships. The problem there is that its military spending was pretty much maxed out. This means you have to pull men from somewhere else. The biggest source of men is the army in China but the army would go insane if you tried that. China was what the war was about for Japan.

That leaves surface warships, subs , and war planes. Less destroyers leave your warships vulnerable to subs and aircraft, less cruisers and battleships give you less fire support, less subs hurt your scouting and less war planes make it harder for you to destroy ships. Personally I would pull them from subs and battleships. Japanese subs didn't do too much during the war and battleships used a lot of manpower. I doubt it will get you enough though. The biggest problem is that Japan was fighting someone with literally ten times their industry. That makes it very, very difficult for them to win.
 
IMHO any POD that allows a Hawaii invasion to succeed needs a POD at least 10 years before 1941. Japan would have to rearrange its military construction priorities so this invasion could be supported, and then you get to the question of what don't they build and where don't they invade as no non-ASB POD is going to make Japanese industrial capacity such that they don't have a major issue with resource allocation. Also you'd need a "PH max" attack, the carriers are in port, there is a third wave hitting oil storage and shops.

As many posters have pointed out in many threads, even if Japan made the decision to invade Hawaii it gains them nothing. No matter what, resources that are needed elsewhere go to Hawaii which pretty much guarantees less success elsewhere. Taking Hawaii will not be the kick to the nuts the Japanese think it would be, the USA will be even more pissed off as word of Japanese excesses against civilians leak out. The USA will devote a greater percentage of effort against Japan than OTL. Long story short, with a POD 10 years before 1941, and good luck over and above what they had OTL, the Japanese MIGHT be able to successfully invade Hawaii, maybe.
 

hipper

Banned
IMHO any POD that allows a Hawaii invasion to succeed needs a POD at least 10 years before 1941. Japan would have to rearrange its military construction priorities so this invasion could be supported, and then you get to the question of what don't they build and where don't they invade as no non-ASB POD is going to make Japanese industrial capacity such that they don't have a major issue with resource allocation. Also you'd need a "PH max" attack, the carriers are in port, there is a third wave hitting oil storage and shops.

As many posters have pointed out in many threads, even if Japan made the decision to invade Hawaii it gains them nothing. No matter what, resources that are needed elsewhere go to Hawaii which pretty much guarantees less success elsewhere. Taking Hawaii will not be the kick to the nuts the Japanese think it would be, the USA will be even more pissed off as word of Japanese excesses against civilians leak out. The USA will devote a greater percentage of effort against Japan than OTL. Long story short, with a POD 10 years before 1941, and good luck over and above what they had OTL, the Japanese MIGHT be able to successfully invade Hawaii, maybe.


I think the point is that if the Japanese had taken Hawaii They might have been able to score a couple of defensive victories and forced the US to the negotiating table I suspect that they would have to engineer a US declaration of war in support of the DEI then decisively defeat the US fleet to force the US to the negotiating table,
 
I think the point is that if the Japanese had taken Hawaii They might have been able to score a couple of defensive victories and forced the US to the negotiating table I suspect that they would have to engineer a US declaration of war in support of the DEI then decisively defeat the US fleet to force the US to the negotiating table,

There are at least two problems with this 1) If they treat US civilians anywhere near the way they treated civilians everywhere else the US isn't going to stop until Japan is a smoking ruin 2) Taking Hawaii makes it extremely difficult to take the DEI which is what they need to continue the war long enough to get to the negotiation table.
 

hipper

Banned
There are at least two problems with this 1) If they treat US civilians anywhere near the way they treated civilians everywhere else the US isn't going to stop until Japan is a smoking ruin 2) Taking Hawaii makes it extremely difficult to take the DEI which is what they need to continue the war long enough to get to the negotiation table.

There are many more than two problems with that but I believe The idea was to defeat America before oil shortages became critical.
 
The basic problem was the Japanese concept of operations was not really to DEFEAT the Americans. Their concept was get a defensive perimeter and then when the soft, weak (etc) Americans tried to break through it the victories would cost them so much blood they would fold. This was different than the German idea of we occupy your country and make you surrender, or in the case of the UK, we bomb your cities to rubble and destroy your Empire then you surrender. The Japanese simply did not understand that once the Americans started their concept would be "we will do to you what Rome did to Carthage, if necessary".

I'm not sure whether Adm Yamamoto ever made this comment, but it has been floating around that his opinion was Japan would defeat America only when Japanese troops dictated the peace in the White House - something even the most fanatic of IJA officers thought could happen.
 
The basic problem was the Japanese concept of operations was not really to DEFEAT the Americans. Their concept was get a defensive perimeter and then when the soft, weak (etc) Americans tried to break through it the victories would cost them so much blood they would fold. This was different than the German idea of we occupy your country and make you surrender, or in the case of the UK, we bomb your cities to rubble and destroy your Empire then you surrender. The Japanese simply did not understand that once the Americans started their concept would be "we will do to you what Rome did to Carthage, if necessary".

I'm not sure whether Adm Yamamoto ever made this comment, but it has been floating around that his opinion was Japan would defeat America only when Japanese troops dictated the peace in the White House - something even the most fanatic of IJA officers thought could happen.

I believe it's pretty well documented that he said:

山本 五十六 said:
Should hostilities once break out between Japan and the United States, it would not be enough that we take Guam and the Philippines, nor even Hawaii and San Francisco. To make victory certain, we would have to march into Washington and dictate the terms of peace in the White House. I wonder if our politicians (who speak so lightly of a Japanese-American war) have confidence as to the final outcome and are prepared to make the necessary sacrifices.
 
Japan is in a bit of a Catch 22 situation here. The easiest way to solve the problem is to have Japan build more Oilers and supply ships. The problem there is that its military spending was pretty much maxed out. This means you have to pull men from somewhere else. The biggest source of men is the army in China but the army would go insane if you tried that. China was what the war was about for Japan.
Up thread, we learned some shocking information, and that was that due to the oil embargo, all of Japan's tankers were sitting around rusting in port. What I still don't know is can the tankers be used by the Oilers at sea/underway? If so, then it turns out that Japan has many times the capacity to supply their fleet, but only a portion of the capacity needed to support their economy. The troops will not be made up from any other source but the IJA.

IMHO any POD that allows a Hawaii invasion to succeed needs a POD at least 10 years before 1941. Japan would have to rearrange its military construction priorities so this invasion could be supported, and then you get to the question of what don't they build and where don't they invade as no non-ASB POD is going to make Japanese industrial capacity such that they don't have a major issue with resource allocation. Also you'd need a "PH max" attack, the carriers are in port, there is a third wave hitting oil storage and shops.
A Japanese invasion of the Hawaiian islands doesn't require the building of 10 years worth of anything. Japan already has all the Oil, tankers, merchant shipping, and troops it needs to invade the Hawaiian islands on Dec 7th, 1941. What they don't have is enough merchant shipping to do this and all their other opening moves from OTL as well.
 
Japanese Oil reserves, how long they can operate, and how long until partial production can be restored once the SRA can be secured.

Japanese oil reserves were required for the operation of the Japanese fleet, the Japanese merchant marine, aviation, and army. The navy burned the most, then the marus. The merchant marine's usage could not be lowered without economic damage, s how long the reserves could last depended on how lavish the Imperial Navy (which consumed over half the amount) was with its operations. With some measures for economy, the reserves might last maybe about 2 years. With robust naval operations such as attacking Hawaii, maybe about 1.5 years.

Production in the NEI could commence about 3 months after capture, taking at least a year, if ever, to reach pre-war levels. There are two territories in question, Sumatra and Borneo. Of the two, Sumatra was the main production sight, but Borneo could be taken more easily and generate maybe about 1 million tons per year, (ie, extend the reserve from 1.5 years to 2 years).

As it turns out, the Japanese have a big shortfall in tankers, if they were getting the oilfields intact, but not so bad with limited production coming online only months later, like in OTL. I'll be wanting to find out just what kind of production the Japanese managed from the captured oil fields, and when this happened.

Rough figures. The initial reserves were 6 million tons. This appears to be in reserve after all initial-op allocations. The amount imported to Japan from the NEI during the entire war was roughly 4 million tons. The total NEI production was much higher, something like 35 million tons during the entire war. That is to say, the strategy of moving the oil to the home islands via tanker was never viable. The fleet and merchant marine eventually had to operate with the NEI as its base of supply.

Where do the Japanese land in the Hawaiian islands, when, and with how many troops? I want to have them hitting as many places as possible, as soon as possible, as the US defense will never be weaker and less prepared than the second week of Dec 1941, and as many airfields must be captured as they can get, in order to start basing large numbers of land based aircraft on the occupied islands.

Every landing needs to be escorted by warships, so it's not a question of a large number of invasions with ridiculous numbers of ships. It's more a question of a couple convoys "making the rounds" to various invasion sights over a period of time. This has to be after the initial battles, though a small number of landings might occur during it. (So, for example, you could feasibly plan a landing on Kauai for a few airfields there and a seaplane base on undefended Niihau in the first day or few of a war).

Do the Japanese have enough aircraft ferries to bring land based planes forward in large numbers?

If Hawaii is the primary objective, even over the NEI, IJN/IJA occupation forces transport is not the bottleneck. The bottlenecks are the inherent brittleness of the IJN fleet carriers to being knocked out of action, (even one bomb can take a flight deck out of action), limited numbers of the best (A6M2, D3A1, B5N2) aircraft and the need to spend large amounts of time in the waters off Hawaii covering landings and supressing air defenses.

In order to stage land based fighter aircraft into occupied Hawaiian islands, do they need midway, assumes that with drop tanks, the aircraft in question would have the range to make it all the way from forward staging bases, if they can use midway as a fueling stop, as if this is not possible, then midway still has to be taken ASAP, but the only fighters making it to the rest of the Hawaiian islands will have to be carrier fighters or ferried in.

Depends on the fighter. A6M2's can be ferried by a small carrier to within maybe 500nm of Hawaii then fly the remaining distance on its own. An a5m4 or KI-27 would need to be ferried much closer, to within perhaps 100nm, or just transported all the way. Twin engine bombers and 4-engine seaplanes could get there on their own.

How much shipping is going to have to be earmarked for this operation, and how much do they have to spare, given OTL operations against the UK and the DEI are delayed?

Tonnange required depends on the plan executed. Maybe 1 to 1.5 million tons, plus tankers. The attack on Malaya can go forward via Thailand, (the Guards Division marched into Malaya overland) with only small landing operations, (say Singora, Thailand only, for example). Luzon cannot occur, but Mindanao can be taken to blockade Luzon from the south. Borneo can still be taken immediately and its oil production re-established as a top priority.


Also, given that the air campaign against the FEAF must go on like OTL, to prevent these forces from being withdrawn and redeployed, how many land based aircraft are going to be available for use in the Hawaiian theater?

That question is backwards to how operational planning occurs. How many aircraft would be required to take the primary objective, Hawaii. Then, deducting them, how would the remaining aircraft assigned to the Southern Operation be used to be effect? (The way you worded it is the formula for disaster, falling between two stools).

Seaplanes, the types, numbers and capabilities.

Seaplanes are more dependent on base availability, but assuming that's not an issue, probably something about 60 single engine and 12 4-engine types in Hawaii, with 60/12 in reserve at the Marshalls as attritional replacements.

Basically, if the Japanese are coming to take over, they need to plan to bring everything they can, and keep it in theater as long as the issue is in doubt.

Right, do the plan to win in Hawaii, then draft the plan for the Southern Op with what's left.

This means that the historical raid needs augmented, as the OTL results didn't eliminate US airpower entirely, and I don't see the KB being able to do that at the same time as they are hitting the fleet. The only thing I can think of that could be used in the ATL PH attack is something with the one-way range to bring a large weapon to bear against high value targets with very great accuracy is the H6K configured as a Kamikaze.

No, that's a very bad idea.

At the time of the PH attack, 1st Air Fleet command intended to launch two distinct waves of two deckloads each. But around this time - so shortly that the idea probably was already being contemplated - Kusaka and Genda were considering massed tactics where multi-deck strikes would be combined into one giant wave. To do this, the first wave launches to orbit while the second wave is brought up on deck. When the 2nd wave launch commences, the first wave departs towards Hawaii and the second wave catches up during transit. A third group of search aircraft departs after the second wave. The first wave is composed of 48 fighters and 126 Kate bombers. The second wave is 36 fighters and 108 dive bombers, (only 108 dive bombers because the 2nd wave has to be limited to 18 strike aircraft per carrier for speed, so the ships with 27 dive bombers would only send 18). The search forces are 4 E13 seaplanes and 18 Kates. The reserve elements are 27 x D3A1 (9 each from Kaga, Shokaku and Zuikaku).

The 108 dive bombers and 84 fighters all hit the airfields simultaneously, not in two waves. 90 bombers attack the battleships, the other 36 attack airfields. That attack plan will, for all intents and purposes, wipe out Hawaii's land based airpower in the first strike. AA losses will be minimal, and a second full-strength strike can be launched on the same day.
 
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SsgtC

Banned
Japanese oil reserves were required for the operation of the Japanese fleet, the Japanese merchant marine, aviation, and army. The navy burned the most, then the marus. The merchant marine's usage could not be lowered without economic damage, s how long the reserves could last depended on how lavish the Imperial Navy (which consumed over half the amount) was with its operations. With some measures for economy, the reserves might last maybe about 2 years. With robust naval operations such as attacking Hawaii, maybe about 1.5 years.

Production in the NEI could commence about 3 months after capture, taking at least a year, if ever, to reach pre-war levels. There are two territories in question, Sumatra and Borneo. Of the two, Sumatra was the main production sight, but Borneo could be taken more easily and generate maybe about 1 million tons per year, (ie, extend the reserve from 1.5 years to 2 years).
You're overestimating reserves. Japanese strategic reserves were sufficient for 18 months of operations at current operational tempos. Or in other words, they were good for 1.5 years without starting a campaign against the US, UK and Dutch. Once that campaign began, with it's vastly higher operational requirements, their reserves dropped to about 1 year's supply.
 
You're overestimating reserves. Japanese strategic reserves were sufficient for 18 months of operations at current operational tempos. Or in other words, they were good for 1.5 years without starting a campaign against the US, UK and Dutch. Once that campaign began, with it's vastly higher operational requirements, their reserves dropped to about 1 year's supply.

The reserves were enough for about 1.5 years of wartime operations. The big difference between war and peace time was the IJN warships. During peacetime these consumed perhaps 300,000 tons of oil in training per year. During wartime, that amount went up by more than a factor of 10, more than 3 million tons of oil consumed by the Japanese navy between December 7th 1941 and December 7th 1942.

Take a heavy cruiser, for example. Call it 12,000 tons and it can move about 7,000nm on 2,000 tons of oil. If it burns 12,000 tons of oil in a year, that's 7,000*6 = 42,000 miles cruise range, or 115 miles per day for 365 days. Given time in port and spend at high speeds, that might be about right or a touch low. Either way, 18 heavy cruisers * 12,000 tons of oil = 216,000 tons as a ballpark for roughly a year's fighting. By guessing and totalling all the different warships, a rough idea of requirements emerges, and it looks more like 3 million tons than 6 million tons.
 
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