OT question about Japan invading Hawaii

[CaptBeefheart]

I think shipping, and more importantly port bottlenecks, put a big limit on the number of troops which could be sent to the Pacific theater and properly supplied. So, enough troops would have been sent to secure Hawaii if it had been attacked, but I wouldn't expect those particular divisions to significantly bump up the total number that actually went to the Pac theater.

Cheers,
CC

[aspqrz02]

ORIGINAL: mike scholl 1
Well stated and thought out. Only thing I'd dissagree with is the "12-knot" invasion convoy. While the Japs certainly had some attack transports that could manage this, they lacked any attack cargo vessels and would be using impressed merchant steamers. With these involved, I'd say a "9-knot" convoy was more likely. All in all, it was an operation that might work in a wargame, but not in real life (or even a good simulation game.).

ISTR reading somewhere that the *average* speed of Japanese Marus was about two thirds that - 5-6 kts - because they couldn't produce the required high pressure valves and other ironmongery for their merchant marine in the amount required. (Conversely, the average speed of Allied Merchanters was evidently 9 kts)

I'd suspect they could manage an initial invasion convoy of 9-12 kt ships, but the resupply pipeline would have to be mostly the 5-6 knot variety ... some calculations were done on soc.history.what-if and soc.history.wwii some years ago and it was roughly figured that supplying a modest sized Japanese force in Hawaii would eat up pretty much all of the available Japanese shipping used to move the forces to invade the PI, Malaysia, and the DEI.

And not be certainly enough to enable a sufficient force stationed in the Islands to be able to hold them ... and what would be the strategic point, anyway? You'd be forgoing any chance of getting the oil you need within 180 days (actually probably a year, Japanese book-keeping was pathetically bad ... worse than their military planning) before your entire modern economy grinds to a complete halt and starvation looms ... for what? Several Islands with no resources worth spit?

I'm not saying the Japanese couldn't have somehow deluded themselves into believing it would somehow be a knockout blow and force the US to give them all the oil they wanted, but that seems way more deluded than anything else they managed to believe. YMMV.

Phil

[aspqrz02]

ORIGINAL: wdolson
On the other hand, the US was at its industrial peak. I read somewhere that in 1940 the US had over 50% of all the industrial output on the planet. The war in Europe had been a big boost to the US economy and it was coming back. In 1905 the Russians had few ships under construction and had few resources to lay down more to replace losses. In 1941 the US had a gigantic fleet under construction or in sea trials. It was one of the most dramatic naval build ups in US history.

I believe the 50% figure applies to the end of WW2 ... and is boosted, of course, by all the war damage to secondary industrial powers like Germany and Japan (and Russia).

Phil

[guytipton41]

ORIGINAL: aspqrz

...

I'd suspect they could manage an initial invasion convoy of 9-12 kt ships, but the resupply pipeline would have to be mostly the 5-6 knot variety ... some calculations were done on soc.history.what-if and soc.history.wwii some years ago and it was roughly figured that supplying a modest sized Japanese force in Hawaii would eat up pretty much all of the available Japanese shipping used to move the forces to invade the PI, Malaysia, and the DEI.

...
Phil

Ah!

That's what your sig so familiar, I lurked at soc.hist.ww2 for years.

Cheers,
Guy

[aspqrz02]

And for those who don't, it is still an interesting place to learn all sorts of useless information about WW2 and related stuff [:D]

And has about as many trolls as here, sadly [8|]

Phil

[ilovestrategy]

Thanks for all the replies. I received quite an education! [&o]

[mike scholl 1]

ORIGINAL: aspqrz

ORIGINAL: mike scholl 1
Well stated and thought out. Only thing I'd dissagree with is the "12-knot" invasion convoy. While the Japs certainly had some attack transports that could manage this, they lacked any attack cargo vessels and would be using impressed merchant steamers. With these involved, I'd say a "9-knot" convoy was more likely. All in all, it was an operation that might work in a wargame, but not in real life (or even a good simulation game.).

ISTR reading somewhere that the *average* speed of Japanese Marus was about two thirds that - 5-6 kts - because they couldn't produce the required high pressure valves and other ironmongery for their merchant marine in the amount required. (Conversely, the average speed of Allied Merchanters was evidently 9 kts)

I'd suspect they could manage an initial invasion convoy of 9-12 kt ships, but the resupply pipeline would have to be mostly the 5-6 knot variety ... some calculations were done on soc.history.what-if and soc.history.wwii some years ago and it was roughly figured that supplying a modest sized Japanese force in Hawaii would eat up pretty much all of the available Japanese shipping used to move the forces to invade the PI, Malaysia, and the DEI.

And not be certainly enough to enable a sufficient force stationed in the Islands to be able to hold them ... and what would be the strategic point, anyway? You'd be forgoing any chance of getting the oil you need within 180 days (actually probably a year, Japanese book-keeping was pathetically bad ... worse than their military planning) before your entire modern economy grinds to a complete halt and starvation looms ... for what? Several Islands with no resources worth spit?

I'm not saying the Japanese couldn't have somehow deluded themselves into believing it would somehow be a knockout blow and force the US to give them all the oil they wanted, but that seems way more deluded than anything else they managed to believe. YMMV.

Phil

I was assuming they would use the best/fastest ships available forsuch an operation..., but you are right in that the great majority of Japanese Maru's were pretty slow. Another thing to keep in mind was that on December 6th, 1941, the Japanese were using over 10,000,000 tons of merchant shipping to keep their economy and war effort functioning. As of December 8th, this fell to a bit over 6,000,000 tons. The remainder had been composed of hired foriegn ships which immediately headed for Allied or neutral ports when the war broke out. The Japanese were able to capture a number of these, but the reality was that an already week merchant marine was drastically reduced just at the moment when the need increased. As I said earlier, for Japan, the entire war was "operation shoestring".

[Gridley380]

Just a note: USS Ranger DID serve in the Pacific - check her DANFS entry. She did so, however, as a training ship late in the war.

By US standards she was indeed a poor fleet carrier... but compare her to Junyo, say, and I think you might re-evaluate her a bit.

IMO she would have been committed if the US got desperate.

[witpqs]

ORIGINAL: Gridley380

Just a note: USS Ranger DID serve in the Pacific - check her DANFS entry. She did so, however, as a training ship late in the war.

By US standards she was indeed a poor fleet carrier... but compare her to Junyo, say, and I think you might re-evaluate her a bit.

IMO she would have been committed if the US got desperate.

As a training carrier, she could be kept where waters were deemed tranquil enough.

Anyway, the real concern about her that I read was sea-keeping in rough seas. How does Junyo rate in that sense?

[Chickenboy]

ORIGINAL: Gridley380

Just a note: USS Ranger DID serve in the Pacific - check her DANFS entry. She did so, however, as a training ship late in the war.

By US standards she was indeed a poor fleet carrier... but compare her to Junyo, say, and I think you might re-evaluate her a bit.

IMO she would have been committed if the US got desperate.

Agreed.

Heck, guys, Ranger WAS deployed successfully across the Atlantic, IRL. To say that she wouldn't have been deployed to the Pacific under desperate circumstances or that she would have foundered after leaving sheltered waters is, IMO, overstating the unfounded fears of the prewar time about her seaworthiness.

[wdolson]

The real reason the Ranger wasn't transferred to the Pacific may have been more political than anything else. It may have been politically difficult to leave the Atlantic fleet with 0 carriers, so they were thrown a token bone by leaving the Ranger there.

The Ranger probably would not have been suitable to the western Pacific which has cyclones, but the eastern Pacific rarely has a hurricane that strays north of the Mexican border. None have in my life time, though growing up in Los Angeles once or twice we got the humidity from a hurricane that had blown out south of us. The fast carriers did sail into some cyclones late in the war and many ships were damaged, some sunk. The Hull class DDs were especially poor handling in rough weather. They were small and very heavily overloaded by 1944 with extra radar, AA, etc.

For battles in the eastern Pacific, the Ranger probably would have been adequate. She did serve as a training carrier out of California ports from 1944 on, so the navy didn't have concerns too serious about operating in those waters.

The Eastern Pacific can get rough, but probably no more so than the North Atlantic.

Bill

[Bearcat2]

I visited Hawaii and tried to visit all the prewar fortifications. I thought that the only way to conquer the islands is to land on Kauai, about 90 miles from Oahu. It had 2 deep water ports, at least 2 airfields on dec7th and it's defense force consisted of the 3/299th NG Bn. On dec 7th, 1941; there were less than 800 military on the island with only 2 75mm field pieces. If you got control of the air over Oahu from Kauai airfields, you could starve them out- around 85% of the islands food had to be imported. Slim chance, because of the logistics involved, but still a better option than trying to land on Oahu with it's 36,000 troops on dec 7th 1941.

[TSCofield]

ORIGINAL: mike scholl 1

ORIGINAL: SimHq Tom Cofield

ORIGINAL: ilovestrategy

It's pretty obvious that after June of 42 that Japan would never take Hawaii. But did they ever have a chance? Maybe in December 1941 they had a shot but even then. I do not know the speed of WW2 troop ships but I cannot imagine them keeping up with the KB.

What do you guys think? Did Japan ever have a shot at it?

will post here since this is the legitimate question.

Personally no. I think others have posted good points but here are a couple of mine.

1. There was no assumption of success at Pearl Harbor. In some respects the attack was specatular beyond what the planners had hoped but there were still multiple CAs and CLs in service, at least the Pennsylvania could have sailed rather quickly once out of drydock. Within 24 hours the US could have managed to set sail with 2CAs, 3CLs and probably a dozen DDs. Maybe the Pennsylvania if she could be provisioned and sent out quickly. The KB would have had to stick around and take care of these ships, along with the other BBs still in port but locked behind sunken ships and rest of the air power left on the island. While the attack crippled the USAAC on the island not all of the aircraft were completely destroyed and probably 40-75 aircraft could still scramble within 24 hours. Aircraft repair facilities were still intact on the island. That means the KB would not have been in a good position for continued support of the invasion once the act of sinking all remaining fleet assets as well as remaining aircraft was done. Add to that the knowlege that the USN still had her carriers at sea and assuming they would be steaming at full speed to support the Navy. The KB would have to keep something back to deal with the US carriers when they ultimately did appear.

2. The IJN invasion fleet would probably have had to sail from Japan. The Marshalls were just not set up to handle such a large invasion force in waiting. A force that big would have had to be trained, provisioned and loaded onto ships. It would take days to weeks to load them from a large port, the Marshall Islands didn't have facilities large enough to do this. Adding to the troubles would be the need to sail 3800 miles to Hawaii. A fleet that large probably would make, at best, 12 knots when you consider the weather. That's almost two weeks at sea. If the force had to go to the south due to the weather it probably would be longer. Not ignoring the fact that the transport force would be made up of the best troop transports in the IJN you would still have to somehow keep two to three divisions of troops combat capable over that time. The Pacific in December is not a hospitable place and 30 thousand seasick troops would have a hard time doing much of anything. Troopships are not cruise liners.

3. To support a fleet that big would require pulling warships off of duty in other places. It might undermine attacks in Malaya. It is easy to assume that the Prince of Wales and Repulse would have been sunk now but there was no body of knowlege that stated such ships would be lost when attacked at full speed, at sea. The Japanese had to support their invasion force with a powerful surface fleet just in case. Likewise any attack on the Phillipines could have been interdicted by the US Asiatic fleet, although it was pretty much scattered. Many of the warships that were supporting other invasions and would have been needed to support the invasion fleet. Again, it would never have been assumed that the US Pacific fleet would have been destroyed at Pearl Harbor so the IJN would have had to plan for at least a half a dozen battleships, cruisers and destroyers attacking their transport fleet. Even a couple of cruisers and a handful of destroyers would have reaped havoc among a minimally protected invasion fleet.

I don't think that anyone in the IJN or IJA seriously thought they could take or hold Hawaii. It would have required the diversion of resources desperately needed to take the DEI or New Britain later. Even the attacks on Malaya could have been disasterous if the support ships were gone 5,000 miles away. For the assault to work too many things would have had to go right repeatedly, something that rarely, if ever, happens in wartime. Via hindsite it was possible to get troops ashore, maybe but who knows.

Well stated and thought out. Only thing I'd dissagree with is the "12-knot" invasion convoy. While the Japs certainly had some attack transports that could manage this, they lacked any attack cargo vessels and would be using impressed merchant steamers. With these involved, I'd say a "9-knot" convoy was more likely. All in all, it was an operation that might work in a wargame, but not in real life (or even a good simulation game.).

I was being generous with my assessment. Having said that, the IJN would have probably used their best transports for the invasion.

[TSCofield]

ORIGINAL: Termite2

I visited Hawaii and tried to visit all the prewar fortifications. I thought that the only way to conquer the islands is to land on Kauai, about 90 miles from Oahu. It had 2 deep water ports, at least 2 airfields on dec7th and it's defense force consisted of the 3/299th NG Bn. On dec 7th, 1941; there were less than 800 military on the island with only 2 75mm field pieces. If you got control of the air over Oahu from Kauai airfields, you could starve them out- around 85% of the islands food had to be imported. Slim chance, because of the logistics involved, but still a better option than trying to land on Oahu with it's 36,000 troops on dec 7th 1941.

Not a bad spot but still vulnerable, especially once the KB withdrew. The issue would not be taking that island, but exploiting the invasion. Just like the difficulties the US had maintaining the Phillippines Japan would have had serious troubles maintaining that Kauai. Even with the success on Dec 7th there was still a sizeable naval force at Pearl Harbor still able to attack the invasion transports and the USAAF could have probable put 100 aircraft back up in the air within 48 hours. A significant force of warships would be needed to protect that invasion fleet, especially if it was at anchor 90 miles from Pearl. The USN could engage in night attacks against the invasion force while getting back to Pearl long before the Japanese Air Force could retaliate. The airfields on Kauai were operational but in 1941 had limited facilities available and I doubt they could handle both the fighters needed to protect the airfields and ships as well as the bombers needed to continue to reduce Hickam and Pearl Harbor.

The USAAF would have continued to fly in larger numbers of B-17s into Hickam and would have used the top tier facilities there to engage in continuous bombing missions against the Japanese forces there. Besides reducing Hickam there would be dozens of smaller fields that the Japanese would have had to reduce along with multiple ports and places where aircraft and troops could be disembarked.

The entire island would have been bypassed and reduced.

[Bullwinkle58]

ORIGINAL: SimHq Tom Cofield

Not a bad spot but still vulnerable, especially once the KB withdrew. The issue would not be taking that island, but exploiting the invasion. Just like the difficulties the US had maintaining the Phillippines Japan would have had serious troubles maintaining that Kauai. Even with the success on Dec 7th there was still a sizeable naval force at Pearl Harbor still able to attack the invasion transports and the USAAF could have probable put 100 aircraft back up in the air within 48 hours. A significant force of warships would be needed to protect that invasion fleet, especially if it was at anchor 90 miles from Pearl. The USN could engage in night attacks against the invasion force while getting back to Pearl long before the Japanese Air Force could retaliate. The airfields on Kauai were operational but in 1941 had limited facilities available and I doubt they could handle both the fighters needed to protect the airfields and ships as well as the bombers needed to continue to reduce Hickam and Pearl Harbor.

The USAAF would have continued to fly in larger numbers of B-17s into Hickam and would have used the top tier facilities there to engage in continuous bombing missions against the Japanese forces there. Besides reducing Hickam there would be dozens of smaller fields that the Japanese would have had to reduce along with multiple ports and places where aircraft and troops could be disembarked.

The entire island would have been bypassed and reduced.

In addition to all this, which is true, Japan would have found very limited pier logistics on Kauai to force men and supplies through. Manila was a world-class harbor and port. I doubt Kauai had more than a couple of wooden or short concrete piers on the whole island. Japan would need Seabes for this and they didn't have any.

[wdolson]

Island warfare demonstrated that many mutually supporting island bases is much better than one or two bases in an island group. Holding only one island the Japanese would be at a disadvantage in the air. Their air attacks on US bases can be defended by planes from other air fields while there would be no supporting air fields to protect Japanese bases from US air attacks. Once the fighters are whittled down at the one field they hold, the US can attack any supply caches or large equipment they find in Japanese territory, making Japan's supply situation worse.

Granted the US would be very inexperienced and the Japanese would start with an experience edge. This would allow the situation to hang in the balance longer, but I think the long term conclusion would be the same. The Japanese would be at the end of a very long supply line trying to hold onto one island with a moderate port in the middle of an island chain controlled by the enemy and most likely much better supplied.

In 1941, the Japanese merchant marine would be stretched out to the max supplying combat in several areas the longest haul being to Hawaii. If the merchant ships to Hawaii aren't heavily escorted, the US would intercept many and sink them, so the IJN has to tie down a lot of warships making sure the convoys get through.

On the other hand the US is supplying Hawaii which would be the shortest run for supplies to a combat zone the US merchant marine had to run in the war. The US mainland to Hawaii is a long run, but the US merchant marine is built with those kind of runs in mind. The supply situation in Hawaii for US troops might get a little tight at times, but their supply situation would be much better than the Japanese.

It's an interesting what if to explore though.

Bill

[mike scholl 1]

ORIGINAL: wdolson

Island warfare demonstrated that many mutually supporting island bases is much better than one or two bases in an island group. Holding only one island the Japanese would be at a disadvantage in the air. Their air attacks on US bases can be defended by planes from other air fields while there would be no supporting air fields to protect Japanese bases from US air attacks. Once the fighters are whittled down at the one field they hold, the US can attack any supply caches or large equipment they find in Japanese territory, making Japan's supply situation worse.

Granted the US would be very inexperienced and the Japanese would start with an experience edge. This would allow the situation to hang in the balance longer, but I think the long term conclusion would be the same. The Japanese would be at the end of a very long supply line trying to hold onto one island with a moderate port in the middle of an island chain controlled by the enemy and most likely much better supplied.

In 1941, the Japanese merchant marine would be stretched out to the max supplying combat in several areas the longest haul being to Hawaii. If the merchant ships to Hawaii aren't heavily escorted, the US would intercept many and sink them, so the IJN has to tie down a lot of warships making sure the convoys get through.

On the other hand the US is supplying Hawaii which would be the shortest run for supplies to a combat zone the US merchant marine had to run in the war. The US mainland to Hawaii is a long run, but the US merchant marine is built with those kind of runs in mind. The supply situation in Hawaii for US troops might get a little tight at times, but their supply situation would be much better than the Japanese.

It's an interesting what if to explore though.
Bill

Is it? A real "what if" I mean. Since the "troll" left the discussion my impression has been that everyone pretty much agreed that the whole idea was "Operation Impossible" for any number of reasons. Lack of troops, lack of suitable shipping, the virtual impossibility of making an undected approach with such a large slow convoy, lack of experiance in making opposed landings, the strength of the defenses on the only landing beaches usable in December..., the list seems endless. Even the "quality" issue is in doubt, as the five American fighters that DID get into the air that morning did quite well against horrible odds. Except under the conditions of a "game", I think we've pretty muched determined that the possibility is nothing but a "pipedream".

[wdolson]

It's still a "what if" scenario, even if the consensus is that it would have been a massive misadventure. I've always thought "what if" scenarios posited something, such as a single change to a historical event, and then we spin the likely scenario from there. Some of these scenarios may lead to a better outcome than historical, others to worse outcomes. Most of the time I think they lead to worse outcomes because they were options explored, at least briefly, by the historical commanders and they were deemed too risky or just plain unworkable.

Bill

[mike scholl 1]

Can't argue with your point Bill. But the one I was making is that this particular "missadventure" really isn't suitable to be explored in WITP-AE simply because the "game" actually gives it a modest chance of working. There is no mechanism in the game to simulate the result of a large Japanese Convoy being directed into an area of the Pacific where it's presense can mean nothing but war..., like steaming towards Hawaii, or down the Malayan coast, or into the waters of the Philippine Islands or the Dutch East Indies. No "tripped trigger" that can destroy any Japanese chance for achieving "surprise", or allow all Allied forces one or two or even three turns of "reaction" when some Japanese players' totally absurd plan to begin the war with landings at Rangoon or Hawaii or Darwin is put into play.

[catwhoorg]

Nor does WITP-AE cover just what a desperate (and starving) civilian population could do if cut off from their food convoys.