1941 - invading Hawaii, possible?

[Hammerbolt]

Hio. This is just an exercise in "what if". regarding a possible invasion of Hawaii by Japan, in December 1941, with the attack on Pearl Harbour as percursor. The IJN attacks Pearl, then the army invades, with the IJN covering.

Now, before you bring out the torches and pitchforks, please read on. Every related whatif I've seen shows such in invasion being carried out at the same time as all the other ops Japan did in OTL. This, afaik, is so much ASB it's laughable at best; Japan did not have the troops and logistics to carry this out, specially fuel. Some minor variations are ocasionally made but, essentially, the authors have Japan invade/attack everthing they did as well as invade Hawaii... so... yeah... hahaha.

My question is this: what if Japan doesn't do all of this? What if it's decided to stomp the US completely out of the Pacific, by taking over is primary base, Hawaii, as the only priority?
Send just enough to the Philippines to raid it, just to destroy it's aircraft, ships & facilities, ignore Guam and Wake (they are too weak and isolated to be an issue). The other major change would be not to attack the British Empire (not even Hong Kong), as well as the Dutch colony (ie, Indonesia) at this time. Any such attack would be left for latter, after the US was forced into an armistice, having lost Haway (supposedly, ofc).

So, if all those ships, troops and specially fuel was diverted, could it have been enough to support an invasion of Hawaii?

(please ignore any strategic/political consequences, such as this avoids bringing the UK a war in Asia, which they could not really afford in 41/42; I'm just trying to get a grasp on the logistics)

 

[sparky42]

Off the top of my head there’s no could pull that off between fuel levels for the ”invasion fleet”, the need to keep the fleet at the islands to support the invasion and number they would need to overcome the garrison.

 

[YYJ]

An invasion immediately after Pearl Harbour would avoid all the subsequent reinforcement that made the invasion even more impossible, but other people will have to give the American Order of Battle in Hawaii in December '41.

If Japan did not invade the DEI, then I don't know how they would replenish the oil reseves they used for the Hawaii invasion. I suppose a scenario could be written where they are still trading with the Dutch.

 

[nbcman]

Past discussions on the plausibility and lack thereof of this scenario:

WI: "Why just bomb Pearl harbour?" Total Japanese Conquest of Hawaii.

So this is the what if: Japan instead of just bombing Pearl harbour, they flat out invade and hold Hawaii...

www.alternatehistory.com

Japanese victory in the pacific war - is it really ASB?

Hey guys. I've long been interested in the pacific war, and the main question on my mind has ever since been: Did the japanese have a chance to win? I read a lot of threads on this site and the predominant opinion seems to be that a japanese victory in the pacific war (i.e. gaining dominance...

www.alternatehistory.com

Japanese Invasion of Pearl Harbor

A scenario from the Internet: https://navy-matters.blogspot.com/2019/04/japanese-invasion-of-pearl-harbor.html All credit belongs to ComNavOps. I copied the post in its entirety for ease of discussion, but please check out the author's blog. Here’s another ‘what if’ version of history: what...

www.alternatehistory.com

What if Japan had successfully invaded Hawaii?

What if, during WW2, Japan landed in Hawaii and took control of it? Ik it would have been impossible for this to happen due to the US navy presence, but what if it did? What if the Japanese somehow pulled it off with some sort of master planning, spies, or something happening that would have...

www.alternatehistory.com

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

I suppose the answer is "not very much", but how plausible is it for the Japanese to be a little more ambitious and rather than just destroy the fleet stationed at Hawaii instead try to invade and occupy Oahu? Do the Japanese even have the transport ships necessary for the job?

www.alternatehistory.com

And there are more threads than that. Short answer is the IJ forces would be outnumbered by the defending US forces and would be invading either into the face of US coastal defenses on the South Shore or 20’-30’ swells on the North Shore. Suicide if attempted IOTL or ASB if an author proposes it.

 

[CV12Hornet]

Yeah, fuel is a very big problem, specifically fuel for the Kido Butai. Simply, the Kido Butai was running on empty by the end of the day on December 7th; sticking around much longer means leaving their destroyers behind and sticking around to support the invasion fleet as it lands means leaving everything behind - the convoy is not going to reach Hawaii’s shores until the 8th at the earliest.

And that invasion convoy would desperately need Kido Butai air cover. Mostly due to Enterprise entering strike range - the Japanese did a thorough job of wiping out Hawaii’s land-based bomber strength. Still, Enterprise left unchecked would be a very large problem for the Japanese. Not to mention the Navy could have organized a fairly sizable cruiser-destroyer force - heavy cruisers New Orleans and San Francisco, light cruisers St. Louis, Phoenix, and Detroit, and over 20 destroyers were left untouched.

Further, the invasion convoy taking so long, and the usual Japanese tendency to land away from the toughest defenses and marching overland, gives the defenders time to get organized - IOTL mobilization of the garrison was impressively fast, and the defenders at the coastal defense station at Haleiwa should be up and ready for the landing. This is bad news for the Japanese, because that fort had four 8” guns, and is right next to the most likely landing site on the north of the island.

So the Japanese might get ashore, but they’re going to take horrendous losses from the air, sea, and by coastal fort (if they make it ashore at all, mind), and still have to March 20 miles overland to get at the good stuff on the south of the island. With no air cover, and minimal supplies, and facing most of a 43,000-man garrison

 

[CV12Hornet]

And thanks for the links, because they reminded me of the fact that the north shore of Oahu in December is prime surfing time. Not so great for landing an invasion force. So you have to try for the south shore of Oahu, which has you attacking into the teeth of the coastal defenses and Army garrison, increases the odds of Enterprise running into the convoy before it reaches the shore, and also shortens the distance any surface combatants have to go.

Also, it adds more time for the defenders to organize. The Kido Butai took a northerly route to avoid shipping lanes and the convoy will have to do so as well, leaving aside the convenience of being near a strong escort and its refueling supplies. This also increases the distance travelled, which... well, see below.

Further, that shipping pool is going to be moving a lot less than 11 divisions. The tyranny of distance hits sea shipping just like it does land-based supply.

 

[Hammerbolt]

And there are more threads than that. Short answer is the IJ forces would be outnumbered by the defending US forces and would be invading either into the face of US coastal defenses on the South Shore or 20’-30’ swells on the North Shore. Suicide if attempted IOTL or ASB if an author proposes it.

Even if they took the troops used on the invasion of the Philippines or Malaya?

Yeah, fuel is a very big problem, specifically fuel for the Kido Butai. Simply, the Kido Butai was running on empty by the end of the day on December 7th; sticking around much longer means leaving their destroyers behind and sticking around to support the invasion fleet as it lands means leaving everything behind - the convoy is not going to reach Hawaii’s shores until the 8th at the earliest.

So the Japanese might get ashore, but they’re going to take horrendous losses from the air, sea, and by coastal fort (if they make it ashore at all, mind), and still have to March 20 miles overland to get at the good stuff on the south of the island. With no air cover, and minimal supplies, and facing most of a 43,000-man garrison

I know all of this, which is why wanted to strip all other forces (almost) and focus on Hawaii; just send enough ships to the shores of the Phillipines to destroy the airfields and, at least, damage the US fleet there. Completely ignore Malaya and other UK-owned areas, and Indonesia. Every ship and drop of fuel is aimed at Hawaii.

 

[sparky42]

Even if they took the troops used on the invasion of the Philippines or Malaya?

I know all of this, which is why wanted to strip all other forces (almost) and focus on Hawaii; just send enough ships to the shores of the Phillipines to destroy the airfields and, at least, damage the US fleet there. Completely ignore Malaya and other UK-owned areas, and Indonesia. Every ship and drop of fuel is aimed at Hawaii.

So what do they achieve even in that case? They’ve burned through huge stockpiles of their fuel reserves and haven’t got the DEI fields, and has the US coming for them…

 

[CalBear]

Invading?

Sure.

Succeeding?

Not a chance in hell. The Japanese flat could not support even a brigade size force that far from home (if one reviews Japan's "Lunge South" the most striking thing is that, with the exception of South Seas Detachment (~4,900 men) they simply could not support large forces more than about 800 miles from a major base. The Landings in the Phillipines? two divisions, but under 400 miles from Formosa. Malaya and Singapore? Final transit point for the 25th Guards was Vietnam (630 miles from the eventual landings), after initial load on Hainan island, with additional japanese force crossing into Malaya across a land border with Thailand. Borneo? Over 1,000 miles, but only a Brigade.

The Japanese barely had enough tankers to support the Pearl Harbor Raid (numerous Japaness was ships, including the Akagi, DECK LOADED fuel drums so their destroyers could make the round trip. Any invasion is going to be with, maybe, one carrier as air cover. Not going to be even close to enough. The Air Corps had 11 B-18s, 5 A-20s, 16 P-36 and 27 P-40s fully combat capable AFTER the Raid. Another 10 P-18, 5 A-20, 30 P-40s and 19 P-36 were damaged but repairable. The Marine had 6 F4f and 14 SBD undamaged and combat ready at Ewa. The USN had TWO carriers, one of which was inside of strike range to the south of Oahu, a second that was about two days out, and the Saratoga a week's transit away. It is going to get really lonely on the possible Japanese carrier.

On the Ground? the U.S. had TWO Full REGULAR ARMY divisions on Oahu, the 24th and 25th. they were among the most combat ready of any unit in the U.S. military on December 7th. Full TOE, regular service troops. There were two Marine Defense Battalions on the island, heavily armed and with per-positioned defensive position configured to repell landing attempts. They were supported by 116th Coastal Artillery Regiment with 2 14' guns, eight 8" guns, sixteen 6" rifled Guns, twelve 305mm mortars, and various lighter guns.

Prior to early 1944 there was not a military on the Planet that could have invaded Hawaii and lived to tell the tale. When one finally came along it was based at Pearl Harbor, which rended the whole invasion thing sort of moot.

 

[CV12Hornet]

Even if they took the troops used on the invasion of the Philippines or Malaya?

I know all of this, which is why wanted to strip all other forces (almost) and focus on Hawaii; just send enough ships to the shores of the Phillipines to destroy the airfields and, at least, damage the US fleet there. Completely ignore Malaya and other UK-owned areas, and Indonesia. Every ship and drop of fuel is aimed at Hawaii.

Doesn’t matter. The fast oilers not assigned to fueling up the First Air Fleet were, in the main, already assigned to invasion convoys and could not and cannot be spared from that duty.

As for troops, shipping for 11 divisions the relatively short distances in Southeast Asia is shipping for a hell of a lot less when you have to lug everything over three thousand miles from Japan.

 

[Hammerbolt]

So what do they achieve even in that case? They’ve burned through huge stockpiles of their fuel reserves and haven’t got the DEI fields, and has the US coming for them…

Hey, I never said it was a sane option... then again, neither was much of the japanese planning...

 

[Deleted member 2186]

Past discussions on the plausibility and lack thereof of this scenario:

WI: "Why just bomb Pearl harbour?" Total Japanese Conquest of Hawaii.

So this is the what if: Japan instead of just bombing Pearl harbour, they flat out invade and hold Hawaii...

www.alternatehistory.com

Japanese victory in the pacific war - is it really ASB?

Hey guys. I've long been interested in the pacific war, and the main question on my mind has ever since been: Did the japanese have a chance to win? I read a lot of threads on this site and the predominant opinion seems to be that a japanese victory in the pacific war (i.e. gaining dominance...

www.alternatehistory.com

Japanese Invasion of Pearl Harbor

A scenario from the Internet: https://navy-matters.blogspot.com/2019/04/japanese-invasion-of-pearl-harbor.html All credit belongs to ComNavOps. I copied the post in its entirety for ease of discussion, but please check out the author's blog. Here’s another ‘what if’ version of history: what...

www.alternatehistory.com

What if Japan had successfully invaded Hawaii?

What if, during WW2, Japan landed in Hawaii and took control of it? Ik it would have been impossible for this to happen due to the US navy presence, but what if it did? What if the Japanese somehow pulled it off with some sort of master planning, spies, or something happening that would have...

www.alternatehistory.com

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

I suppose the answer is "not very much", but how plausible is it for the Japanese to be a little more ambitious and rather than just destroy the fleet stationed at Hawaii instead try to invade and occupy Oahu? Do the Japanese even have the transport ships necessary for the job?

www.alternatehistory.com

And there are more threads than that. Short answer is the IJ forces would be outnumbered by the defending US forces and would be invading either into the face of US coastal defenses on the South Shore or 20’-30’ swells on the North Shore. Suicide if attempted IOTL or ASB if an author proposes it.

You can add this to the list, a good article by CombinedFleet called: Invasion: Pearl Harbor!

 

[Hammerbolt]

You can add this to the list, a good article by CombinedFleet called: Invasion: Pearl Harbor!

It's a good article, but that's after the battle of Midway... that's 6-8 months after my modified start; with so many comitments over all of the Pacific and part of the Indian ocean, such an op in late 1942 OTL is not even ASB...

 

[RamscoopRaider]

It's a good article, but that's after the battle of Midway... that's 6-8 months after my modified start; with so many comitments over all of the Pacific and part of the Indian ocean, such an op in late 1942 OTL is not even ASB...

Scroll down and read the "And Then There's the Really Gutsy Scenario" part of the article

 

[Hammerbolt]

Scroll down and read the "And Then There's the Really Gutsy Scenario" part of the article

Duh...

 

[Alanith]

Can they invade? Theoretically yes, if they abandon all other concerns.... they might be able to get two divisions or so ashore.

But in doing so they'd be guaranteed to lose a sizable amount of shipping transportation, warships, rare tankers, and carriers. As well as burn through quite a bit of fuel. And even if by some miracle they stick with the pre-midway habit of rolling sixes, and pull the whole thing off (I cannot imagine a banzai charge sweeping into Pearl against 14 and 16 inch direct fire from damaged ships in the harbor, for one), what then?

You've burnt through most of the men, ships, and fuel you needed to seize the Dutch East Indies. The whole fucking point of starting the war in the first place.

 

[Captain Seafort]

Doesn’t matter. The fast oilers not assigned to fueling up the First Air Fleet were, in the main, already assigned to invasion convoys and could not and cannot be spared from that duty.

I think that's the point of the OP - what if Japan focuses entirely on destroying the US ability to respond before launching the invasions of the Philippines, DEI and Malaya?

 

[CV12Hornet]

I think that's the point of the OP - what if Japan focuses entirely on destroying the US ability to respond before launching the invasions of the Philippines, DEI and Malaya?

I think you're missing the fact that the Japanese are still going to need invasion convoys in this scenario, they're just steaming to Hawaii rather than hither and yon all over Southeast Asia.

 

[Captain Seafort]

You've burnt through most of the men, ships, and fuel you needed to seize the Dutch East Indies. The whole fucking point of starting the war in the first place.

It also pushes the US back - it's an awfully long way from San Diego to Pearl. Whether the operation is operationally or tactically achievable is a different matter entirely, but it makes strategic sense.

 

[Captain Seafort]

I think you're missing the fact that the Japanese are still going to need invasion convoys in this scenario, they're just steaming to Hawaii rather than hither and yon all over Southeast Asia.

You said "The fast oilers not assigned to fuelling up the First Air Fleet were, in the main, already assigned to invasion convoys and could not and cannot be spared from that duty."

If they're going after Oahu alone then there are no other invasion convoys they need to be spared from. Whether they're sufficient for the lift required to achieve the objective is certainly debatable, but going by the OP those other invasions aren't happening and therefore aren't a logistical factor.