A Japanese invasion of Hawaii

[warspite1]

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.

warspite1

I notice that you are answering fewer and fewer questions - and to be fair, I understand that because the ‘plan’ simply falls apart under any level of questionning.

Essentially you are saying that the Japanese completely and utterly wasted their time in employing the Northern Pacific route. You think they could never be found - and even if they were - there was nothing they couldn’t simply brush off with an excuse and so ensure the US forces were never alerted. You’ve extended this to flotillas of Japanese destroyers sailing up and down the HI.

A superb foundation on which to build any major military operation.

[warspite1]

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.

warspite1

So are the capital ships the tankers now? How many times are the capital ships going to be topping up the destroyers post their own final top-up? The KB are going to war. They don’t know what is coming their way. The ships of the task force need to be fully replenished to allow tactical flexibility. But you seem to be envisaging the ships expending much of their oil topping up flotillas of destroyers on a regular basis.

The Japanese don’t need a Task Force commander, they need a petrol station forecourt attendant....

[RangerJoe]

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.

warspite1

So are the capital ships the tankers now? How many times are the capital ships going to be topping up the destroyers post their own final top-up? The KB are going to war. They don’t know what is coming their way. The ships of the task force need to be fully replenished to allow tactical flexibility. But you seem to be envisaging the ships expending much of their oil topping up flotillas of destroyers on a regular basis.

The Japanese don’t need a Task Force commander, they need a petrol station forecourt attendant....

Not to mention that there were not that many capital ships either and they would also worry about running low on oil. Then having to tow dry destroyers back to a port where they could refuel.

[Aurelian]

The 1st Air Fleet was heading home after the 2nd air strike. Two carriers broke off to strike Wake, then head home. They were not going to stick around and play gas station or provide air cover for a couple of islands not worth taking, let alone held.

They had no idea where the other US carriers were. They had no idea how many subs were around. Nor did they have any idea, AFAIK, how many troops were there

http://niehorster.org/013_usa/_41_usarm ... hawaii.htm is the OOB of the Hawaii Dept.

One would think that would be more than adequate to handle a couple of battalions landed from destroyers.

I'll say it again. The seizure of the SRA was paramount. The IJA was far more concerned with winning in China and securing the resources they needed to do that. The whole idea of the raid on Hawaii was to neutralise the Pacific Fleet so they could secure the SRA. And the PI operation was not going to be postponed for the same reason.

[Platoonist]

Probably of the nicer aspects of this plan from an Allied perspective is that it allows the Pensacola Convoy to sail on through to the Philippines. This US Army convoy escorted by the heavy cruiser Pensacola was in the South Pacific en route to the Philippines via Australia and the DEI when the Pearl Harbor raid took place. Since all the G4M Betty bombers that operated out of Formosa are now going on this mid-Pacific boondoggle and there will be no invasion of the PI, there isn't much to prevent this convoy from docking at Davao in the southern island of Mindanao and staging its aircraft forward to Manila and Clark Field.

The convoy was carrying a provisional brigade from the U.S. Field Artillery Corps, made up of 2,000 National Guard troops. 2,600 U. S. Army Air Forces personnel were also on board, along with aircraft shipped disassembled in crates: 52 Douglas A-24 dive bombers of the 27th Bombardment Group. 18 crated Curtiss P-40 fighter planes of the 35th Pursuit Group. 48 pursuit pilots of the 35th PG traveled aboard too.

Materiel being transported included: 20 75 mm field artillery pieces, AA ammunition, 2,000 500 lb bombs, 3,000 30 lb bombs, 340 motor vehicles, 9,000 barrels of aviation fuel, 500,000 rounds of .50 caliber ammunition and 9,600 rounds of 37 mm anti-aircraft shells. All making Luzon an even bigger headache to any future Japanese lines of communication with the Southern Resource Area, especially those dive bombers operating over the Luzon Straits between Luzon and Formosa.

Historically, this convoy ended up landing most of its contents and passengers in Australia due to the Japanese invasion of the Philippines.

[Buckrock]

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.

There was no operation in the current SRA invasion plans that specifically needed the unique capabilities of APDs for its execution. Even the Wake Invasion didn't rely solely on them. So why would the Japanese have seen any pressing need for more APDs at this point, especially since the conversion would come at a cost to other capabilities.

And then there would be the issue of finding the spare yard space for the conversion of what sounds like a considerable number of destroyers. The Japanese naval and civilian shipyards were already working at full capacity right up to the start of the war, following the schedule that had been laid out in detail the previous financial year. It's not really a situation favourable to Yamamoto being able to just slip a couple of changes past the relavent authorities.

[Buckrock]

The convoy was carrying a provisional brigade from the U.S. Field Artillery Corps, made up of 2,000 National Guard troops. 2,600 U. S. Army Air Forces personnel were also on board, along with aircraft shipped disassembled in crates: 52 Douglas A-24 dive bombers of the 27th Bombardment Group. 18 crated Curtiss P-40 fighter planes of the 35th Pursuit Group. 48 pursuit pilots of the 35th PG traveled aboard too.

Then you can probably also throw in the Army transport Ludington that was carrying another 20 P-40s and other materials for the Philippines. Once it finished its scheduled delivery to Christmas Island, it would have been following only a day or two behind the Pensacola Convoy.

Additionally, another group of B-17s had just started making their way to the Philippines when Dec 7th brought their move to an abrupt halt at Hawaii.

I'd also think the (minimum) one week delay being applied to the war's start may well have meant enough time for the planned B-24 photographic overflight of the Japanese bases in the mysterious Marshall Islands. It may well have revealed the Japanese were preparing their forces there for something big. May have even picked up Curtis Lemay's brand new Betty Field on Eniwetok.

[Orm]

I'd also think the (minimum) one week delay being applied to the war's start may well have meant enough time for the planned B-24 photographic overflight of the Japanese bases in the mysterious Marshall Islands. It may well have revealed the Japanese were preparing their forces there for something big. May have even picked up Curtis Lemay's brand new Betty Field on Eniwetok.

Interesting.

However, any idea on how long it would take to get the photos analysed? Would they have had any priority? One would then have to hope that the analysis would have been correct, and that the report would have had some sort of priority. My point being is that there would have been a time delay from when the picture was taken until an alarm was called for. Anyone has any idea how long such a delay would be? Hours, or days, or maybe a week?

[Buckrock]

I'd also think the (minimum) one week delay being applied to the war's start may well have meant enough time for the planned B-24 photographic overflight of the Japanese bases in the mysterious Marshall Islands. It may well have revealed the Japanese were preparing their forces there for something big. May have even picked up Curtis Lemay's brand new Betty Field on Eniwetok.

Interesting.

However, any idea on how long it would take to get the photos analysed? Would they have had any priority? One would then have to hope that the analysis would have been correct, and that the report would have had some sort of priority. My point being is that there would have been a time delay from when the picture was taken until an alarm was called for. Anyone has any idea how long such a delay would be? Hours, or days, or maybe a week?

Who knows. What can be established is that this mission was a seen as a top priority by the navy. IIRC, the reason it had been delayed was because they had to wait for some parts to be flown from the US to Hawaii so that the B-24s could be equipped with a defensive armament for the flight.

[Buckrock]

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.

Just an FYI about your all important Sunday attack focus. The Japanese should have been able to determine the "two carriers in port on a Sunday" requirement hadn't been met since early November (at least that's what the evidence in the Congressional report on PH suggested about the CVs). All that the Japanese intel had established previously was that Sunday was the day most likely to find the bulk of Hawaiian-based US warships present in port. For some reason the USN CVs (along with many of the CAs) would appear to no longer be following that general rule. When the reports in your scenario then come in for Dec 7th and confirm once again that the CV requirement has failed to be met, wouldn't the Japanese start to wonder whether they should have followed the "never assume" rule?

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.

So does that mean both KB and the APDs have to be together 200nm from the islands at what I assume is early in the night of Dec 6th? If so, does that mean the entire force has made most of its approach to this position pretty much all in daylight?

[Curtis Lemay]

I notice that you are answering fewer and fewer questions - and to be fair, I understand that because the ‘plan’ simply falls apart under any level of questionning.

Just the ones that matter.

Essentially you are saying that the Japanese completely and utterly wasted their time in employing the Northern Pacific route.

Good grief. Can the entire fleet traverse the entire central pacific in one night? Of course not. But the DDs can traverse about 500 miles in the night before the raid.

[Curtis Lemay]

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.

warspite1

So are the capital ships the tankers now? How many times are the capital ships going to be topping up the destroyers post their own final top-up? The KB are going to war. They don’t know what is coming their way. The ships of the task force need to be fully replenished to allow tactical flexibility. But you seem to be envisaging the ships expending much of their oil topping up flotillas of destroyers on a regular basis.

The Japanese don’t need a Task Force commander, they need a petrol station forecourt attendant....

There are eight capitol ships. They have huge fuel stocks - far in excess of DDs. Topping off the DDs would be insignificant to the big guys. And, after the raid, they will all soon be refueled on the way back.

[Curtis Lemay]

Probably of the nicer aspects of this plan from an Allied perspective is that it allows the Pensacola Convoy to sail on through to the Philippines. This US Army convoy escorted by the heavy cruiser Pensacola was in the South Pacific en route to the Philippines via Australia and the DEI when the Pearl Harbor raid took place. Since all the G4M Betty bombers that operated out of Formosa are now going on this mid-Pacific boondoggle and there will be no invasion of the PI, there isn't much to prevent this convoy from docking at Davao in the southern island of Mindanao and staging its aircraft forward to Manila and Clark Field.

The convoy was carrying a provisional brigade from the U.S. Field Artillery Corps, made up of 2,000 National Guard troops. 2,600 U. S. Army Air Forces personnel were also on board, along with aircraft shipped disassembled in crates: 52 Douglas A-24 dive bombers of the 27th Bombardment Group. 18 crated Curtiss P-40 fighter planes of the 35th Pursuit Group. 48 pursuit pilots of the 35th PG traveled aboard too.

Materiel being transported included: 20 75 mm field artillery pieces, AA ammunition, 2,000 500 lb bombs, 3,000 30 lb bombs, 340 motor vehicles, 9,000 barrels of aviation fuel, 500,000 rounds of .50 caliber ammunition and 9,600 rounds of 37 mm anti-aircraft shells. All making Luzon an even bigger headache to any future Japanese lines of communication with the Southern Resource Area, especially those dive bombers operating over the Luzon Straits between Luzon and Formosa.

Historically, this convoy ended up landing most of its contents and passengers in Australia due to the Japanese invasion of the Philippines.

Only the Luzon invasion is being canceled. The rest of the PI operation still takes place.

[Curtis Lemay]

So does that mean both KB and the APDs have to be together 200nm from the islands at what I assume is early in the night of Dec 6th? If so, does that mean the entire force has made most of its approach to this position pretty much all in daylight?

Your own figures were 33 hours at top speed. That would be a range of over 1400 miles. Now, I'm not saying they should spend a full 33 hours at top speed, but they would have had lots of slack to top off soon enough to out-distance the main fleet in order to be in position to make the final run to the islands entirely at night.

[Buckrock]

So does that mean both KB and the APDs have to be together 200nm from the islands at what I assume is early in the night of Dec 6th? If so, does that mean the entire force has made most of its approach to this position pretty much all in daylight?

Your own figures were 33 hours at top speed. That would be a range of over 1400 miles. Now, I'm not saying they should spend a full 33 hours at top speed, but they would have had lots of slack to top off soon enough to out-distance the main fleet in order to be in position to make the final run to the islands entirely at night.

Your range calculation seems a bit off but I've gotta admire your optimism overall. These top-end fuel consumption figures are normally based on a short speed trial (1-2 hours) in good conditions when the ship was just out of the shop. Now change the sea state to moderate/heavy, add the wear and tear of weeks in the Northern Pacific, extend the speed run out to 8-12 hours and then put that single ship in a 12 ship formation at night that has to operate together in unfriendly waters. Consider what impact that has now had on fuel consumption at all speeds and also on the chances of being able to operate at that top speed mentioned in the sales brochure.

During the Guadalcanal campaign when the Tokyo Express destroyers were running the most dangerous part of The Slot in daylight, the formation speeds were still generally kept in the 25-30 knot range. After nightfall, it would drop to 20-25 knots even though they were still in dangerous waters. These guys were conducting missions similar to that of your imagined force. I'd suggest you might want to follow the real life experts in deciding what speeds were practical for your scenario.

It would still be interesting to find out from you where everyone is supposed to start the day before the attack in terms of distances from the Hawaiian Islands as this destroyer mission set up so far is making little sense in terms of timing.

[warspite1]

Only the Luzon invasion is being canceled. The rest of the PI operation still takes place.

warspite1

Not so. You've said you are taking aircraft from the PI operation. You see this is why detail is important. At the moment all you are doing is changing your answers to suit your argument, and you can do this because you never trouble yourself with detail.

[warspite1]

There are eight capitol ships. They have huge fuel stocks - far in excess of DDs. Topping off the DDs would be insignificant to the big guys. And, after the raid, they will all soon be refueled on the way back.

warspite1

But you don't know this. You don't know how many destroyers it would have taken to land your four battalions - let alone the vast amounts of supplies needed by the air units. You say you've wargamed this and yet you can't say what destroyers numbers are required - indeed you now say the Japanese would need destroyer conversions which they didn't have.

'Huge fuel stocks'....seriously? You have the KB (plus goodness knows how many destroyers) sailing for the attack on Pearl. In your scenario though the KB have sailed with the knowledge that they may not make the attack straightaway because they don't know when the carriers will be in port. So they need to be prepared for tooling around in the North Pacific for an indeterminate length of time. Apart from the obvious problems that you've ignored, there is the problem of fuel replenishment.

Based on the known and expected (though not certain) carrier movements, the enlarged KB will have been at sea for over two weeks (it may have been more). The ships would have been burning oil and supplies and sailing from the refuellling point to the flying off point and back again. How long would it take to transfer oil to the destroyer flotillas (assuming one flotilla per island)?

You refuse to provide detail you refuse to provide a timeline. Of course your 'plan' works when you don't have to evidence it.

[warspite1]

I notice that you are answering fewer and fewer questions - and to be fair, I understand that because the ‘plan’ simply falls apart under any level of questionning.

Just the ones that matter.

warspite1

No, the ones that are convenient for you to answer. The others you simply ignore.

[warspite1]

Essentially you are saying that the Japanese completely and utterly wasted their time in employing the Northern Pacific route.

Good grief. Can the entire fleet traverse the entire central pacific in one night? Of course not. But the DDs can traverse about 500 miles in the night before the raid.

warspite1

Again you are changing your argument to suit each question. One of the biggest reasons the Japanese would never have considered this ridiculous plan is that secrecy was vital. They were not going to swan around in the North Pacific for an unknown length of time in the hope of getting the carriers. Why? because they couldn't afford to be detected. But your answer to this was that even if they were detected it wouldn't matter because they would say they were on a training exercise. A training excerise a few hundred miles from the HI????

So if there is no problem with detection, why sail the treacherous Northern Pacific route and be prepared to sink any vessels they come into contact with? Was detection a problem for the KB or not? Please stick to one answer.

[Curtis Lemay]

There was no operation in the current SRA invasion plans that specifically needed the unique capabilities of APDs for its execution. Even the Wake Invasion didn't rely solely on them. So why would the Japanese have seen any pressing need for more APDs at this point, especially since the conversion would come at a cost to other capabilities.

For the operation I'm adding. Yamamoto knows about that and its needs. But he can justify APD conversion to his superiors just in general. APDs are useful things to have.

And then there would be the issue of finding the spare yard space for the conversion of what sounds like a considerable number of destroyers. The Japanese naval and civilian shipyards were already working at full capacity right up to the start of the war, following the schedule that had been laid out in detail the previous financial year. It's not really a situation favourable to Yamamoto being able to just slip a couple of changes past the relavent authorities.

Not building APDs from scratch. Just modifying the superstructure of existing DDs. No slipways or dry docks needed. Just dock space.