A Japanese invasion of Hawaii

[warspite1]

As I said, without further details from Curtis Lemay there's probably no point trying to walk through all the issues relating to his destroyer landing operation. I only supplied a fuel estimate for the historical situation so as to provide a type of general baseline.

But that's just me.

warspite1

No, its not just you. I've been asking for details from the outset and it was the same with Spain. I don't really understansd why Curtis Lemay doesn't believe that details are important in his alternate strategies. Maybe its to hide the knowledge that it won't work, maybe its laziness, who knows? So we are left with a plan that consists of: some planes and some troops and some ships are gonna do some stuff against some islands from some islands using some stuff. How does he know all this? - because a war game says its possible.

A timeline of proposed events is never offered. A suggested OOB is never offered (particularly important to establish given nothing, BUT NOTHING can be allowed to delay the conquest of the NEI).

[Curtis Lemay]

Land them, in the Hawaiian Islands, having sailed to the HI alone....

At night.

warspite1

It doesn't matter. The Japanese - and the second wave was proof of this (as if any was needed) can't afford to be detected. You believe the Japanese would sanction destroyers sailing up to, along, and through the Hawaiian Islands so they could park offshore and await the attack in the desperate hope they weren't detected?

All the Japanese would need just one bit of bad luck and their war against the US, the British and the Dutch has just ended in total disaster....

At night. On a Sunday. In peacetime. Even in the unlikely event they are detected and the detectors immediately tumbled to exactly what they are - in the morning after, the detectors will have perhaps an hour advance before the attack begins. It won't get any further than the report about the sub trying to get into the harbor. You are discounting how oblivious the Americans were.

[Curtis Lemay]

Again, the fully loaded range of the Betty is 3132 miles. Eniwetok to Oahu is 2715 miles. After participating in the raid they will still have 417 miles of range left. Maui is 115 miles from Oahu.

From the Smithsonian Institute:

"At that time, the requirements were unprecedented for a twin-engine, land-based attack bomber: flying at a top speed of 398 kph (247 mph) and an altitude of 3,000 m (9,845 ft), the new bomber had to fly a distance of 4,722 km (2,933 miles) without a torpedo or equivalent weight in bombs. When carrying an 800-kg (1,768 lb) torpedo or the same weight in bombs, the Navy needed the bomber to fly at least 3,700 km (2,300 mi)."


I'm surprised because no mod or vanilla WitP AE itself makes this mission even remotely possible. And the community is full of hardcore freaks that dig and then dig some more to get the data. Needless to say no offense intended, they do a great job

Another model of Betty?

You're quoting the design specs. What resulted is what matters.

This:
https://www.ww2-weapons.com/mitsubishi-g4m-betty/

Says the range with bombs is 3132 miles.

"Aircraft of World War II" says its range was 3749 miles (presumably without bombs).

[Curtis Lemay]

What US troops were on Maui in December 1941?

Maui, Kauai and Hawaii were guarded by the 299th Regiment. Each island had one battalion from the regiment.

This:
https://en.wikipedia.org/wiki/299th_Cav ... _States%29

Says that the regiment was 40% Japanese locals. In June, those were removed from the regiment, leaving it at 60% strength.

It doesn't say which islands got them, but each battalion would be about the strength of two companies after that deduction. So, two Jap battalions, with surprise on their side, already in the interior of island, strike two companies of US on a Sunday in peace time.

[warspite1]

At night. On a Sunday. In Peacetime.

warspite1

Japanese destroyer(s). 6,600km from Japan. Within a few hundred km of Hawaii.

You are discounting that any advance warning could spell disaster for the KB’s precious aircraft and aircrew.

[Curtis Lemay]

I know there were already destroyers escorting the historical mission. They were destroyers that had had their weights reduced in the name of fuel efficiency, including the reduction in the number of ship's boats. For the same reason, crew comforts like heating, washing, air conditioning, etc were planned to be kept at a bare minimum. Very much the opposite of the overcrowded and overweight destroyers on your mission. Given the conditions the Japanese expected to encounter in the North Pacific at that time of the year, bringing along destroyers carrying troops in the hope of an opportunity to invade and capture some (defended) Hawaiian islands would be asking a bit much even with the backing of Divine Providence.

Again, they have months to prepare. Older destroyers could have gotten APD type modifications to specially handle troops and supplies - reducing armament to do so. This was done during the war. It could have been done pre-war.

[Curtis Lemay]

At night. On a Sunday. In Peacetime.

warspite1

Japanese destroyer(s). 6,600km from Japan. Within a few hundred km of Hawaii.

You are discounting that any advance warning could spell disaster for the KB’s precious aircraft and aircrew.

You are discounting how badly detection and alerting was bungled in the historical event. How do you determine something you spotted at night was a Japanese ship? Assuming you could even spot it?

At full speed most DDs could do about 43 miles per hour (37 knots). In an 12-hour night that's 516 miles.

[warspite1]

I know there were already destroyers escorting the historical mission. They were destroyers that had had their weights reduced in the name of fuel efficiency, including the reduction in the number of ship's boats. For the same reason, crew comforts like heating, washing, air conditioning, etc were planned to be kept at a bare minimum. Very much the opposite of the overcrowded and overweight destroyers on your mission. Given the conditions the Japanese expected to encounter in the North Pacific at that time of the year, bringing along destroyers carrying troops in the hope of an opportunity to invade and capture some (defended) Hawaiian islands would be asking a bit much even with the backing of Divine Providence.

Again, they have months to prepare. Older destroyers could have gotten APD type modifications to specially handle troops and supplies - reducing armament to do so. This was done during the war. It could have been done pre-war.

warspite1

But the Japanese didn’t. They had what they had. So what were you using to wargame this scenario? How many destroyers did the Japanese need to use for this in your scenario?

[warspite1]

At night. On a Sunday. In Peacetime.

warspite1

Japanese destroyer(s). 6,600km from Japan. Within a few hundred km of Hawaii.

You are discounting that any advance warning could spell disaster for the KB’s precious aircraft and aircrew.

You are discounting how badly detection and alerting was bungled in the historical event. How do you determine something you spotted at night was a Japanese ship? Assuming you could even spot it?

At full speed most DDs could do about 43 miles per hour (37 knots). In an 8-hour night that's 344 miles.

warspite1

You are talking about two flotlillas of destroyers in Hawaiian waters. We know what happened in real life, but surely you can understand that each time you add an element that could ruin the surprise, you increase the chances of er... well, ruining the surprise. If the Japanese parachuted a 100 ton concrete elephant onto Pearl on December 6th in your plan, would you assume it was undetected just because of what happened in real life on December 7th?


The destroyers are doing 37 knots on the run in to HI? Really? What does that mean for fuel consumption?

[RangerJoe]

At night. On a Sunday. In Peacetime.

warspite1

Japanese destroyer(s). 6,600km from Japan. Within a few hundred km of Hawaii.

You are discounting that any advance warning could spell disaster for the KB’s precious aircraft and aircrew.

You are discounting how badly detection and alerting was bungled in the historical event. How do you determine something you spotted at night was a Japanese ship? Assuming you could even spot it?

At full speed most DDs could do about 43 miles per hour (37 knots). In an 8-hour night that's 344 miles.

Well, you should read about the Ushio and what happened to her. Then decide how hard it was to spot her, damage her, and then force her to retreat.

The speed that you are stating would be difficult to maintain for that length of time. It is more than likely done under special speed trials and not under battle condition after sailing for many days away from any repair capabilities other than what was onboard the ship. Also, where would the IJN get the extra destroyers needed to do this if they were also going after the DEI and the rest of the Southern Resource Area?

As far as ethnic Japanese on the Hawaiian Islands, how many actually helped Japan after the war started?

[Shellshock]

So, if I'm understanding this scenario correctly, the plan is to seize the outer Hawaiian islands and then try to blockade and bomb Oahu until it's garrison is weakened enough to either surrender or let you take it by assault? This is gonna be a months long process if it even works.

I can't help but make comparisons to the besieged island of Malta in the Mediterranean. There, the Axis held all the cards around a much smaller island in their back yard. They had large, well supplied airfields in Italy linked by road and rail overland to their industrial centers. They had total command of the surrounding sea and air. Yet, the British with great grit somehow got convoys through the Sicily-North Africa narrows to Malta and delivered additional Spitfires by carrier launch. Closing off something as large as Oahu with much more open ocean about it will be much more difficult and will tie down large numbers of air, land and sea forces, plus corresponding logistical assets, for the duration.

The US can probably stage air reinforcements through Johnston Island to the south or by launching Marine Wildcat squadrons from carriers like they did at Wake before the war started. Plus, B-17s can be brought over to Oahu from the mainland directly and they'll start pummeling these local grass airstrips pretty quickly. I doubt if any of those airfields on Kauai or Maui had defensive revetments or dispersal areas and Zeros found the B-17 a tough nut to crack.

So imagine Malta where the Axis is operating at the far end of 4,000 mile long shipping line to captured enemy airstrips where replacement aircraft have to be ferried in over those same vast stretches of open water with no navigational landmarks. Those planes can't carry the aviation fuel, lubricating oil, spare parts, engineering equipment, ammunition, and literally everything else you need to sustain pressure on Oahu. Where does the ordinance come from to sustain this operation I have no idea. Perhaps bombs grow on palm trees? At some point slow, vulnerable cargo ships will have to do it. What are the port and cargo handling facilities like in these local islands? Probably tiny.

American submarines can readily reach Hawaii from the West Coast plus there are the Line Islands to the south as advanced bases for the fleet. Cutting off Japanese supply is within easy reach as early as mid 1942 even when the torpedoes work only somewhat.

After all US submarines sank over a million tons in 1942 even with the faulty Mark 14 torpedoes.

I think if the Imperial GHQ ever got wind of a plan like this they would ask that it's authors have their sake rations cut to nothing.

[vonRocko]

This topic doesn't fall into the category of "what if". It is in the "never would/could have happened" category.

[Aurelian]

warspite1

Japanese destroyer(s). 6,600km from Japan. Within a few hundred km of Hawaii.

You are discounting that any advance warning could spell disaster for the KB’s precious aircraft and aircrew.

You are discounting how badly detection and alerting was bungled in the historical event. How do you determine something you spotted at night was a Japanese ship? Assuming you could even spot it?

At full speed most DDs could do about 43 miles per hour (37 knots). In an 8-hour night that's 344 miles.

warspite1

You are talking about two flotlillas of destroyers in Hawaiian waters. We know what happened in real life, but surely you can understand that each time you add an element that could ruin the surprise, you increase the chances of er... well, ruining the surprise. If the Japanese parachuted a 100 ton concrete elephant onto Pearl on December 6th in your plan, would you assume it was undetected just because of what happened in real life on December 7th?


The destroyers are doing 37 knots on the run in to HI? Really? What does that mean for fuel consumption?

All I can say is that it is no longer a historical event when you make it a "what if".....

Most IJN destroyers could go 3,600nm at 14kts. Double that speed, you may get 1/2 of range, probably less. Then they have to sit there with steam up until the troops land. Which will cost fuel. How long will that take to offload? The heaviest weapons they could carry would be mortars. How many rounds will be carried? How much food? Rifle/machine gun ammo? Spare parts? And for how long will they have to hold at the end of a long, fragile, supply line?

[Buckrock]

I know there were already destroyers escorting the historical mission. They were destroyers that had had their weights reduced in the name of fuel efficiency, including the reduction in the number of ship's boats. For the same reason, crew comforts like heating, washing, air conditioning, etc were planned to be kept at a bare minimum. Very much the opposite of the overcrowded and overweight destroyers on your mission. Given the conditions the Japanese expected to encounter in the North Pacific at that time of the year, bringing along destroyers carrying troops in the hope of an opportunity to invade and capture some (defended) Hawaiian islands would be asking a bit much even with the backing of Divine Providence.

Again, they have months to prepare. Older destroyers could have gotten APD type modifications to specially handle troops and supplies - reducing armament to do so. This was done during the war. It could have been done pre-war.

Months to prepare? Surely you mean weeks. Yamamoto's original plan was only grudgingly accepted by the Tokyo decision makers during the second half of October. Without their authorization, Yamamoto had no real power to start pulling warships out of service and sending them to shipyards for changes to their role and capabilities. And his plan would have seemed a comparative safe bet compared to yours. IGHQ would have taken some convincing based on what you've put forward so far.

But I doubt those conversions would've have fixed your problem even if they had been approved and completed in time. Their range performance would have been a major issue had they tried to accompany KB, at least it would have been if from the point of view of real world Japanese planners.

[Buckrock]

warspite1

Japanese destroyer(s). 6,600km from Japan. Within a few hundred km of Hawaii.

You are discounting that any advance warning could spell disaster for the KB’s precious aircraft and aircrew.

You are discounting how badly detection and alerting was bungled in the historical event. How do you determine something you spotted at night was a Japanese ship? Assuming you could even spot it?

At full speed most DDs could do about 43 miles per hour (37 knots). In an 8-hour night that's 344 miles.

warspite1

You are talking about two flotlillas of destroyers in Hawaiian waters. We know what happened in real life, but surely you can understand that each time you add an element that could ruin the surprise, you increase the chances of er... well, ruining the surprise. If the Japanese parachuted a 100 ton concrete elephant onto Pearl on December 6th in your plan, would you assume it was undetected just because of what happened in real life on December 7th?

The destroyers are doing 37 knots on the run in to HI? Really? What does that mean for fuel consumption?

Well they're certainly not doing it if they were the APD conversions he mentioned earlier. Had they been instead the more modern IJN DD classes like the Kageros that did accompany KB for the raid, for every hour at their top speed of 35 knots, they would burn about 15 tons of oil in calm conditions. And if the conditions worsened, the speed would drop but the burn rate (as well as the strain on the propulsion system) would continue unabated. Most warship sources list the Kageros as having a fuel capacity of 500 tons, so that would equate to 33 hours of oil at top speed.

But I doubt any commander would want to risk the engines by running a WWII destroyer at anywhere close to its top speed for the length of time Curtis Lemay is suggesting.

I also noted that we still don't have any details on the IJN destroyer positions (in relation to Hawaii) in the plan other than they're out there somewhere and arrive in time to invade during the night prior to the PH raid.

[Bo Rearguard]

I know there were already destroyers escorting the historical mission. They were destroyers that had had their weights reduced in the name of fuel efficiency, including the reduction in the number of ship's boats. For the same reason, crew comforts like heating, washing, air conditioning, etc were planned to be kept at a bare minimum. Very much the opposite of the overcrowded and overweight destroyers on your mission. Given the conditions the Japanese expected to encounter in the North Pacific at that time of the year, bringing along destroyers carrying troops in the hope of an opportunity to invade and capture some (defended) Hawaiian islands would be asking a bit much even with the backing of Divine Providence.

Again, they have months to prepare. Older destroyers could have gotten APD type modifications to specially handle troops and supplies - reducing armament to do so. This was done during the war. It could have been done pre-war.

Months to prepare? Surely you mean weeks. Yamamoto's original plan was only grudgingly accepted by the Tokyo decision makers during the second half of October. Without their authorization, Yamamoto had no real power to start pulling warships out of service and sending them to shipyards for changes to their role and capabilities. And his plan would have seemed a comparative safe bet compared to yours. IGHQ would have taken some convincing based on what you've put forward so far.

But I doubt those conversions would've have fixed your problem even if they had been approved and completed in time. Their range performance would have been a major issue had they tried to accompany KB, at least it would have been if from the point of view of real world Japanese planners.

Weren't conversions to APDs pretty much a one way street? It seems if you start yanking out boilers, torpedo mounts and guns and cutting the deck down for Daihatsu landing craft ramps it isn't ever going to be a front line destroyer again. I can't imagine Combined Fleet being too keen on mass converting a good portion of its destroyer fleet into slower, less capable fighting units.

[Buckrock]

That's normally the case but if I read him correctly, he seemed to be referring to the half dozen Mutsuki class conversions that occured late in '42. Most of those converted seem to have kept all their boilers. Sources vary on their speed after conversion but they generally were considered heavier and slower than when they were pure DDs. Japanese accounts from the Solomons Campaign never appear to show them operating much above 30 knots, even when USN DD's were in pursuit.

[Curtis Lemay]

warspite1

Japanese destroyer(s). 6,600km from Japan. Within a few hundred km of Hawaii.

You are discounting that any advance warning could spell disaster for the KB’s precious aircraft and aircrew.

You are discounting how badly detection and alerting was bungled in the historical event. How do you determine something you spotted at night was a Japanese ship? Assuming you could even spot it?

At full speed most DDs could do about 43 miles per hour (37 knots). In an 8-hour night that's 344 miles.

warspite1

You are talking about two flotlillas of destroyers in Hawaiian waters. We know what happened in real life, but surely you can understand that each time you add an element that could ruin the surprise, you increase the chances of er... well, ruining the surprise. If the Japanese parachuted a 100 ton concrete elephant onto Pearl on December 6th in your plan, would you assume it was undetected just because of what happened in real life on December 7th?

So...you'd object even if I added stealth fighters? Because at night, on a Sunday, in peacetime, that's about how detectable these destroyers would be.

The destroyers are doing 37 knots on the run in to HI? Really? What does that mean for fuel consumption?

They can top off before they start their run from some of the capitol ships. They can make the 200 mile run to the islands, drop off the troops and be 200 miles away by dawn. Top off again and make the supply run after the raid starts.

[Curtis Lemay]

Months to prepare? Surely you mean weeks. Yamamoto's original plan was only grudgingly accepted by the Tokyo decision makers during the second half of October. Without their authorization, Yamamoto had no real power to start pulling warships out of service and sending them to shipyards for changes to their role and capabilities. And his plan would have seemed a comparative safe bet compared to yours. IGHQ would have taken some convincing based on what you've put forward so far.

But I doubt those conversions would've have fixed your problem even if they had been approved and completed in time. Their range performance would have been a major issue had they tried to accompany KB, at least it would have been if from the point of view of real world Japanese planners.

No. I mean months. He doesn't have to have any plan approved for everyone to see the need for APDs in general. Easy to cover it that way.

[RangerJoe]

You are discounting how badly detection and alerting was bungled in the historical event. How do you determine something you spotted at night was a Japanese ship? Assuming you could even spot it?

At full speed most DDs could do about 43 miles per hour (37 knots). In an 8-hour night that's 344 miles.

warspite1

You are talking about two flotlillas of destroyers in Hawaiian waters. We know what happened in real life, but surely you can understand that each time you add an element that could ruin the surprise, you increase the chances of er... well, ruining the surprise. If the Japanese parachuted a 100 ton concrete elephant onto Pearl on December 6th in your plan, would you assume it was undetected just because of what happened in real life on December 7th?

So...you'd object even if I added stealth fighters? Because at night, on a Sunday, in peacetime, that's about how detectable these destroyers would be.

I did not know that you were a comedian. How detectable are destroyers? I told you to read what happened to the Ushio. She was very detectable and was damaged at night by AAA.

To detect the destroyers, all that it would have taken was a pleasure boat or a fishing boat with a radio.