The Pacific War begins without the Pearl Harbour raid. USN actions?

[Gunner's_Quadrant]

Were all 3 divisions of the Kido Butai to ALWAYS work together as a FIXED doctrine? Or was this only what Yamamoto wanted?

Doctrine is how you plan and train to fight. That does't preclude the exigencies of war preventing you from following your doctrine but if you have the choice you try to follow your doctrine. There is no such thing as FIXED doctrine, but you don't want to spend months or years training to fight in a certain way to enhance your strengths or minimize your weaknesses and then just stop doing that as soon the fighting begins. For example, the US Army had doctrine for its Field Artillery and Tank Destroyer branches. The Field Artillery doctrine emphasized massed, responsive fire. A single observer could be controlling the fires of a DivArty and one or two supporting FA Groups, 7-9 battalions; this doctrine worked. The Tank Destroyer Branch's doctrine to was to mass its TD's around enemy breakthroughs and stop the breakthrough, unfortunately, this doctrine didn't play out. There weren't too many breakthroughs, definitely not in the numbers envisaged in 1940/1941; as a result the doctrine never worked. Instead US Tank Destroyers were used in the artillery role or as a substitute tank, neither of which they excelled.

Regarding the Indian Ocean Raid (Operation C), Kaga was to be part of the raid but hit an uncharted reef before the operation and had severely reduced speed, so it was sent back to Japan for repairs. Otherwise, it would have been on the operation. If you read the reports, the Kido Butai followed doctrine, utilizing massed attacks usually in multiple waves with each carrier division forming a portion of the strike package.

From what I remember about Operation MO, there were a couple of reasons that the whole Kido Butai wasn't deployed. First, the ships that had been in the Indian Ocean needed to refit after a period of intense operations. The Zuikaku and Shokaku being relatively new, only commissioned in fall 1941, didn't need the refit as much as were available to support the operation. Also, the IJN didn't rate the threat level very high.

 

[Gunner's_Quadrant]

the big killer of PH, the AP bombs dropped by Kates in level bomber mode, would not be a factor.

Where are you getting this from? The big killer was the aerial torpedo. Of the 4 active battleships sunk, the California and Oklahoma were solely due to torpedo hits, the West Virginia took 7 torpedo and 2 AP bomb hits (I would tend to lean towards torpedoes being the primary cause of her sinking); only the Arizona can be solely attributed to AP bombs.

Maryland and Tennessee were at inboard positions and only received 2 AP bomb hits each and they were considered to be available for duty within a month. Most of the AP bombs that did hit were duds or low order explosions. Take a look at Zimm, "Attack on Pearl Harbor", he has a lot of data that shows what ships were hit and by what weapons. He calculates that 20% of the AP bombs dropped were actual hits (10 out of 50).

The level bombers did better than the Val divebombers which hit only 19% of the time. This is somewhat amazing considering that the Val units in the upcoming few months would have considerably higher hit levels and at Pearl Harbor they were attacking stationary targets. Zimm hypotheses that the combined stratified cloud cover and the smoke from the earlier attacks obscured the Val bomber pilots vision and significantly reduced their hit levels.

Everything I've read on Pearl Harbor, points to the conclusion that the high level AP bombing attacks were not very effective and those bombers would have been better utilized in the torpedo role.

 

[marathag]

All the other Battleship losses were from multiple torpedo hits, along with bombs, while only Arizona was knocked out with a single fatal bomb attack.

Now I have posted pics on how ugly Nevada's damage was, showing that even a single Type 91 torpedo was nothing to shrug off.

But Nevada was not at full power, and could not maneuver in the channel, and all watertight doors and hatches not closed

An attack on the high seas with the ship's fully manned AAA and able to maneuver, is a whole different matter than what happened on Dec. 7th.

From 40 torpedo drops, had 17 hits against stationary targets. That won't be the case with a Task Force in operation.

 

[McPherson]

the big killer of PH, the AP bombs dropped by Kates in level bomber mode, would not be a factor.

Being at battle stations makes a difference too.

USN estimated that a maneuvering ship target was 8x harder to hit that a similar sized building. Hence dive bombers.

And it's not like the USN was happy to hand over their perfect superweapon, the Mk13, to the Army in any case.

But took not much change in equipment for Pappy Gunn to find that skip bombing worked far better, since it didn't have the drop requirements of the Mki13, like drop speed, and didn't need a skilled bombardier, either.
He could be left home, and then you can fill the nose full of MGs and ammo for better strafing to suppress AAA(such as it was) on the attack run

Depends. Warships are a bit tougher than merchantmen.

Bomb = repair of topside damage at Yokusuka. Torpedo = Japanese war grave full of honored dead. Depends on the location of the holes.

 

[CV12Hornet]

So, the bottom line is: Did the IJN expect the decisive battle to happen immediately in the aftermath or during the Southern Operation. Or, in other words, did the IJN expect the US to come at them with everything immediately, basically Plan Orange/Rainbow.

If that‘s a yes, then preserving the KB as a unified force makes sense. We will likely see the KB operate not around Wake, since trying to have the decisive battle around Wake so early was not in the IJNs interest or doctrine. They wanted to achieve attrition with submarine and land aircraft attacks first. They will probably back up the southern operation with it, meaning more bad news for the already outnumbered allied fleets/flotillas.

If that‘s a no, then splitting up the KB makes sense.

Finally let us not neglect the element of distance. It will take weeks for the US to get their slow, intact battleline to S.E. Asia. The Japanese have ample of submarines / seaplanes for early warning. Splitting up the Kido Butai will not be permanent, it can reunite, were the USN to show up.
Remember that without a PH attack, naval engagements will still be considered to happen in WWI style. The very concept of mobile carrier battles is still not ripe,

According to Conway's 1922-1946, the initial assumptions were that the Americans would come after the Southern Operation was complete, or at least after they had time to seize and fortify Guam, Wake, and the Philippines. Obviously, Yamamoto and other senior officers came to disagree with that, hence the Pearl Harbor operation.

And I disagree that the concept of mobile carrier battles wasn't ripe. Both the US and Japan expected carrier battles and in fact desired to remove the other's carriers before any big gun brawl. The Japanese relied heavily on spotter planes for the gunnery tactics, the US on their dive bombers for scouting, and neither wanted the other to be able to launch a massed air attack in the middle of the big brawl, which regardless of the effects in sunk or damaged ships would be a catastrophic distraction. Hence the large proportion of dive bombers in the air wings of both navies, dive bombers being the best means of taking out carriers at the time.

Plus isn't this the Midway plan, just earlier.

If Wake is attacked in Dec of 41 and beats off the 1st wave (as happened in RL) don't you think there would be a major sortie from PH as a rescue mission? Wake was the closest point to PH so the USN rounds up a relief task force and sets sail. Maybe 2 carriers, 4 battleships and numerous cruisers and destroyers as well as the transports.

The Wake relief force was heavily limited in terms of size by the availability of fast oilers to refuel at sea. There isn't enough at-sea oil in the Pacific to support four battleships and their attendant escorts on top of the OTL carriers, escorts, and transports. The OTL operation alone consumed 60% of the at-sea fuel and that's without having to fight a battle.

 

[Draconis]

Though straying a little from my OP I was thinking about this question. Would the the absence of the attack on Pearl Harbour have affected the decision to intern the Japanese-Americans? Two main differences from OTL is there would not had been the same amount of shock and fear generated by the heavy losses the Americans suffered in Hawaii. The fighting in the Philippines on the other side of the world wouldn't have provoked the same fear of invasion or attack on the U.S. West coast as was experienced in OTL after the PH attack.

Also there would have been no Niihau Zero incident. https://en.wikipedia.org/wiki/Niihau_incident

The events on Niihau caused much concern about the possible divided loyalties of the Japanese-Americans. However unjustified these fears may have been I think things would have been better if there hadn't been a Pearl Harbour surprise attack.

 

[BlackDragon98]

I smell a decisive confrontation coming up.
Maybe near Midway or Wake?

 

[McPherson]

You been reading my ATL?

 

[cladglas]

Anarch King of Dipsodes
there were 4 or 5 radars in USAFFE, though one was completely inop, one was on the move to northwest luzon, one was down at paracale on the legaspi peninsula, & the one at Iba that detected the raids that attacked luzon on the 8th.(& the recon flights during the previous week). USAFFE wasn't caught by surprise.

 

[cladglas]

McArthur refused to authorize Hart's Asiatic Fleet Patrol wing to approach More then 1/2 way to Formosa. The Catalinas could have done the recon( with better shipping IDs) and overflown all of Formosa., allowing all the B_17s to strike Formosan airfields.

no. macarthur didn't control the asiatic fleet.

 

[McPherson]

no. macarthur didn't control the asiatic fleet.

Under the theater command concept in use at the time, MacArthur could tell Hart what to do. Hart just ignored him and in the chaos, nobody forced the issue with the other problems (Like losing the entire FEAAF caught on the ground.) having to be sorted out.

 

[MUC]

And I disagree that the concept of mobile carrier battles wasn't ripe. Both the US and Japan expected carrier battles and in fact desired to remove the other's carriers before any big gun brawl. The Japanese relied heavily on spotter planes for the gunnery tactics, the US on their dive bombers for scouting, and neither wanted the other to be able to launch a massed air attack in the middle of the big brawl, which regardless of the effects in sunk or damaged ships would be a catastrophic distraction. Hence the large proportion of dive bombers in the air wings of both navies, dive bombers being the best means of taking out carriers at the time.

Prior to the PH raid, the only major attack on warships by planes was the Taranto raid by the RN (if you ignore the Bismarck hunt).

The concept was certainly not "ripe" by the beginning of WWII and all sides were learning things. The Japanese were the first and only who decided to combine their carriers in one battlegroup, forming the Kido Butai. The USN doctrine did not foresee that. The USN still thought the battleline was important.
I am not saying the IJN did not consider battleships important. They did, which is why they built the Yamato and Musashi and even had plans for bigger ships. But the IJN certainly embraced the concept of the highly mobile, multi-carrier task force, able to conduct operations independently earlier than other Navies.




Some points concerning the effectiveness of the AP bombs vs. torpedoes in PH.
When the Japanese designed the strike, they did not expect to find the USN totally unprepared. Had the Americans manned battle stations or even gotten ships underway by the time the attack wave came, the destruction caused by the low-flying, slow torpedo bombers would have been less pronounced.
Furthermore the issue of shallow harbor waters was still there, although the contingencies developed by the IJN did work. The Japanese also had some intelligence on possible anti-torpedo nets in the harbor, but they did have to speculate on the presence/effectiveness of smaller nets around the battleline too.
One final point is how the ships were "parked" in PH.

Torpedoes were only useful in hitting the ships parked "on the outside". Hitting Maryland, Tennessee , Arizona, Pennsylvania with torpedoes in not possible.

An "all out torpedo" may seem like a good idea in retrospect, did however involve risks and would leave ships "untouched".

 

[Naval Aviation Fan]

The concept was certainly not "ripe" by the beginning of WWII.

But the IJN certainly embraced the concept of the highly mobile, multi-carrier task force, able to conduct operations independently earlier than other Navies.

I read your bolded words at the beginning of your post, while knowing that it isn't true as historically proven by The Pearl Harbor raid, which for some reason the Japanese have mysteriously elected NOT to do here in this ATL (and we have a vacuum for what they do with the KB instead), but then you go on to disprove your own bolded text with a detailed account of all the training and obstacles that the IJN did prior to the PH raid.

So, historically, the Pacific portion & US entry into WWII started with the very concept you claim was not "ripe" and the beginning of the war, on the very first day of said war, and only after several months of intensive training and preparations by the IJN.

The concept was most definitely "ripe", as it was historically put into use the very day the war started!

In THIS alternate timeline, we are posed the challenge of the IJN throwing away their best chance to inflict losses on the USN at the outset of the war, and then trying to figure out what the USN can start doing to the Japanese, entirely without regard to what the IJN is doing instead of PH. While I can accept the concept of the Japanese deciding against the PH raid, I cannot accept that they are NOT going to be using the KB effectively, and the next best option (and a poor one at that), would be to support their historically abandoned doctrine, by extending their defensive perimeter at least a tiny bit more than OTL as a minimum alternative.

Given that inflicting a massive blow on the USN at the very outset is 100% the best option for day one of the war, and therefore any alternative to that is a lesser option and not as good for Japan, I still want to float "something" being done to improve their position over OTL, instead of, you know, nothing at all.

Historically, that Japanese threw everything they had into an all out initial offensive, and took everything they could, as fast as they could, and then fortified the hell out of it, and then played a waiting game, of making the USN come to them, under their land based and seaplane air cover. If we are asked to ignore the PH raid as being to risky, OK. If we are asked to ignore the alternative opportunity to extend their defensive perimeter by a bit more than OTL (or at least a bit sooner if not farther) on top of this, I have to cry foul.

The entire nature of their opening moves was all about securing a defensive perimeter against the USN and any counter attacks they may attempt, in the first 6 months or so of the war.

All that being said, I'll be posting a bit more detailed alternative later on, but for now a quick and sketchy rundown of my lesser but at least consistent with Japanese OTL mentality initial attack changes would look like this:

On Dec 7th (I'm using PH time so as to avoid confusion with the international date line), the KB, instead of being in close proximity to Oahu, is instead off Wake island, and in addition to the historical invasion shipping used in that battle, they are also joined by the naval and transport shipping OTL employed in invading Guam at the same time as Wake. Understand, Guam is still going to suffer the historical air attacks, but the invasion is delayed so that other, more 'important/developed' islands can be taken on day one instead, as Guam isn't going anywhere, and lacking an airfield/air power, and with just under 600 defenders for an island of over 200 square miles, it isn't as juicy a prize.

So, Dec 7th sees Wake island hit by the KB as well as the historical air attacks.
I'm going way out on a limb here, and calling all US air power stationed on Wake DoA on day one because of this.
I'm also going way out on a limb, and saying Wake island falls in the first invasion attempt.
The new Japanese plan, is to secure an extended defensive perimeter, by taking Wake on day one, followed up by an invasion of Midway island in the post Wake conquest. Transports departing Wake and traveling directly to Midway @10 kts need something like 5 days to get there, and if we take into account a 2 day stay at Wake island, this gives us an earliest arrival at midway of Dec 14th, and a likely successful invasion complete by Dec 21st, once the Japanese have the former US airbases up and running with their own land based aircraft (and remembering our history, the OTL midway invasion had this happening before the USN carriers showed up, so just a day or two later), the Japanese then crown off their initial operations with taking Attu and Kiska islands (which are both undefended, and free for the plucking).

Again, this option is clearly inferior too OTL's PH attack, but it gives us a somewhat more realistic use of Japanese forces than the KN basically sitting in port and doing nothing, which as we all know ain't happening. It doesn't call for the Japanese to mount any attacks that they didn't historically mount, it just has two of them taking place earlier while leaving the taking of Guam for the very near future, and without an airfield, Guam isn't really as important as Midway island.

Anyone got any thoughts or comments about this potential alternate "filling in the holes" type thing?

 

[McPherson]

Prior to the PH raid, the only major attack on warships by planes was the Taranto raid by the RN (if you ignore the Bismarck hunt).

There were only three aircraft carrier users on the planet. Hard to practice your war-gamed tactics in war, if the other users are not fighting you.

The concept was certainly not "ripe" by the beginning of WWII and all sides were learning things. The Japanese were the first and only who decided to combine their carriers in one battlegroup, forming the Kido Butai. The USN doctrine did not foresee that. The USN still thought the battle-line was important.

Yamamoto thought his battle-line was the arm of decision at Midway. Nagumo was just supposed to clear out US air defenses on the island and neutralize (dedeck) PACFLT flattops so that Yamamoto could sail forward to fight the gunline action against the American battleships he expected to be there to fight a Jutland of the Pacific. (Yes, he believed that silliness. It was Nimitz who was all air-power all the time at that juncture of the war.). As it will turn out in the Solomon Islands and into the Leyte fiasco, flattops tend to neutralize each other and then it does come down to SAGs. Last ships floating and holding the battlespace after the gun, aircraft, and torpedo brawl, wins. (SAMAR)

Let us amend that futher.

The IJN had formed the Kido Butai out of their largest aircraft carriers (6 of them at its maximum) to attack on the China coasts (and Pearl Harbor), but were operationally quite happy to parcel them out by divisions (Coral Sea) to undertake operations.

I am not saying the IJN did not consider battleships important. They did, which is why they built the Yamato and Musashi and even had plans for bigger ships. But the IJN certainly embraced the concept of the highly mobile, multi-carrier task force, able to conduct operations independently earlier than other Navies.

As the USN proved at Lae and Salamaua and in the Caroline Islands, Gilbert Island raids and the Doolittle Stunt, this is not true. RAIDING with flattops was an aspect of the 1930 fleet problems as well with the Panama Canal and Pearl Harbor being USN favorite "targets".

Some points concerning the effectiveness of the AP bombs vs. torpedoes in PH.

Inboards were going to be level bombed as the IJNAS thought they were immobile, so why not to get at them? The dive bombers were part of infrastructure FLAK suppression and runway denial in the counter-air package which was the majority of the two strike packages' assignments

When the Japanese designed the strike, they did not expect to find the USN totally unprepared. Had the Americans manned battle stations or even gotten ships underway by the time the attack wave came, the destruction caused by the low-flying, slow torpedo bombers would have been less pronounced.

See what I wrote about the dive bombers. Might add that the IJNAS was shocked and appalled at USN AAA. They had no idea it would be that ferocious and effective.

Furthermore the issue of shallow harbor waters was still there, although the contingencies developed by the IJN did work. The Japanese also had some intelligence on possible anti-torpedo nets in the harbor, but they did have to speculate on the presence/effectiveness of smaller nets around the battleline too.

Target collation was good. Conditions of the anchorage defenses? (USS Ward) The IJN boloed that one.

One final point is how the ships were "parked" in PH.

Torpedoes were only useful in hitting the ships parked "on the outside". Hitting Maryland, Tennessee , Arizona, Pennsylvania with torpedoes in not possible.

An "all out torpedo" may seem like a good idea in retrospect, did however involve risks and would leave ships "untouched".

Hmm. 66% MK on the torpedo accessible targets, 20% on the sitting duck inboards. Should have dive bombed.

I read your bolded words at the beginning of your post, while knowing that it isn't true as historically proven by The Pearl Harbor raid, which for some reason the Japanese have mysteriously elected NOT to do here in this ATL (and we have a vacuum for what they do with the KB instead), but then you go on to disprove your own bolded text with a detailed account of all the training and obstacles that the IJN did prior to the PH raid.

Fleet problem X forward.

So, historically, the Pacific portion & US entry into WWII started with the very concept you claim was not "ripe" and the beginning of the war, on the very first day of said war, and only after several months of intensive training and preparations by the IJN.

I assume Pearl Harbor for real, but lets toss in Operation Judgment and the USN Panama Canal and Pearl Harbor fleet problems and the Caribbean "invasion" of Puerto Rico for G and G's.

The concept was most definitely "ripe", as it was historically put into use the very day the war started!

See previous.

In THIS alternate timeline, we are posed the challenge of the IJN throwing away their best chance to inflict losses on the USN at the outset of the war, and then trying to figure out what the USN can start doing to the Japanese, entirely without regard to what the IJN is doing instead of PH. While I can accept the concept of the Japanese deciding against the PH raid, I cannot accept that they are NOT going to be using the KB effectively, and the next best option (and a poor one at that), would be to support their historically abandoned doctrine, by extending their defensive perimeter at least a tiny bit more than OTL as a minimum alternative.

Knock out Australia.

Given that inflicting a massive blow on the USN at the very outset is 100% the best option for day one of the war, and therefore any alternative to that is a lesser option and not as good for Japan, I still want to float "something" being done to improve their position over OTL, instead of, you know, nothing at all.

Attack the Australian SLOCs.

Historically, that Japanese threw everything they had into an all out initial offensive, and took everything they could, as fast as they could, and then fortified the hell out of it, and then played a waiting game, of making the USN come to them, under their land based and seaplane air cover. If we are asked to ignore the PH raid as being to risky, OK. If we are asked to ignore the alternative opportunity to extend their defensive perimeter by a bit more than OTL (or at least a bit sooner if not farther) on top of this, I have to cry foul.

You could try the Arifura Sea gambit.

The entire nature of their opening moves was all about securing a defensive perimeter against the USN and any counter attacks they may attempt, in the first 6 months or so of the war.

I still think attrite and decrease was their best shot. Keeping the First Air Fleet intact for the Marianas Islands showdown was the best move they could make.

All that being said, I'll be posting a bit more detailed alternative later on, but for now a quick and sketchy rundown of my lesser but at least consistent with Japanese OTL mentality initial attack changes would look like this:

Ways and means.

On Dec 7th (I'm using PH time so as to avoid confusion with the international date line), the KB, instead of being in close proximity to Oahu, is instead off Wake island, and in addition to the historical invasion shipping used in that battle, they are also joined by the naval and transport shipping OTL employed in invading Guam at the same time as Wake. Understand, Guam is still going to suffer the historical air attacks, but the invasion is delayed so that other, more 'important/developed' islands can be taken on day one instead, as Guam isn't going anywhere, and lacking an airfield/air power, and with just under 600 defenders for an island of over 200 square miles, it isn't as juicy a prize.

What does that buy Japan except an Alamo and an enraged America only now with PACFLT intact?

So, Dec 7th sees Wake island hit by the KB as well as the historical air attacks.

What is the net overall military gain for effort expended? Conservation of force applies to any operation.

I'm going way out on a limb here, and calling all US air power stationed on Wake DoA on day one because of this.
I'm also going way out on a limb, and saying Wake island falls in the first invasion attempt.
The new Japanese plan, is to secure an extended defensive perimeter, by taking Wake on day one, followed up by an invasion of Midway island in the post Wake conquest. Transports departing Wake and traveling directly to Midway @10 kts need something like 5 days to get there, and if we take into account a 2 day stay at Wake island, this gives us an earliest arrival at Midway of Dec 14th, and a likely successful invasion complete by Dec 21st, once the Japanese have the former US airbases up and running with their own land based aircraft (and remembering our history, the OTL Midway invasion had this happening before the USN carriers showed up, so just a day or two later), the Japanese then crown off their initial operations with taking Attu and Kiska islands (which are both undefended, and free for the plucking).

What is the point? This is my trouble with Yamamoto and his Combined Fleet staff. They would mount operations and NOT SEE THE POINT. Knocking out Australia as an opening move makes sense, because that is where the Americans will head first after the Philippine Islands are scooped up. Naval Geography 101.

Again, this option is clearly inferior too OTL's PH attack, but it gives us a somewhat more realistic use of Japanese forces than the KN basically sitting in port and doing nothing, which as we all know ain't happening. It doesn't call for the Japanese to mount any attacks that they didn't historically mount, it just has two of them taking place earlier while leaving the taking of Guam for the very near future, and without an airfield, Guam isn't really as important as Midway island.

Guam sits in the middle of the Marianas Islands. That makes it kind of VERY important.

Anyone got any thoughts or comments about this potential alternate "filling in the holes" type thing?

East coast of Australia and Arifura Sea coasts raided. AUSTRALIA is kind of important, too.

 

[MUC]

I read your bolded words at the beginning of your post, while knowing that it isn't true as historically proven by The Pearl Harbor raid, which for some reason the Japanese have mysteriously elected NOT to do here in this ATL (and we have a vacuum for what they do with the KB instead), but then you go on to disprove your own bolded text with a detailed account of all the training and obstacles that the IJN did prior to the PH raid.

So, historically, the Pacific portion & US entry into WWII started with the very concept you claim was not "ripe" and the beginning of the war, on the very first day of said war, and only after several months of intensive training and preparations by the IJN.

The concept was most definitely "ripe", as it was historically put into use the very day the war started!

You are misquoting me.

I said the concept of mobile carrier battles was not ripe, which means carrier groups acting independently and fighting each other.
Which is what happened in the first couple of years of the Pacific War.

And then I said that the Japanese embraced the concept of uniting their carriers into one big carrier battle group, the Kido Butai, and where the first to do so.

Those are two different things. One is the concept of war, as one would think war would take place. The other is the concept of how you are going to deploy you forces.

 

[MUC]

All that being said, I'll be posting a bit more detailed alternative later on, but for now a quick and sketchy rundown of my lesser but at least consistent with Japanese OTL mentality initial attack changes would look like this:

On Dec 7th (I'm using PH time so as to avoid confusion with the international date line), the KB, instead of being in close proximity to Oahu, is instead off Wake island, and in addition to the historical invasion shipping used in that battle, they are also joined by the naval and transport shipping OTL employed in invading Guam at the same time as Wake. Understand, Guam is still going to suffer the historical air attacks, but the invasion is delayed so that other, more 'important/developed' islands can be taken on day one instead, as Guam isn't going anywhere, and lacking an airfield/air power, and with just under 600 defenders for an island of over 200 square miles, it isn't as juicy a prize.

So, Dec 7th sees Wake island hit by the KB as well as the historical air attacks.
I'm going way out on a limb here, and calling all US air power stationed on Wake DoA on day one because of this.
I'm also going way out on a limb, and saying Wake island falls in the first invasion attempt.
The new Japanese plan, is to secure an extended defensive perimeter, by taking Wake on day one, followed up by an invasion of Midway island in the post Wake conquest. Transports departing Wake and traveling directly to Midway @10 kts need something like 5 days to get there, and if we take into account a 2 day stay at Wake island, this gives us an earliest arrival at midway of Dec 14th, and a likely successful invasion complete by Dec 21st, once the Japanese have the former US airbases up and running with their own land based aircraft (and remembering our history, the OTL midway invasion had this happening before the USN carriers showed up, so just a day or two later), the Japanese then crown off their initial operations with taking Attu and Kiska islands (which are both undefended, and free for the plucking).

Again, this option is clearly inferior too OTL's PH attack, but it gives us a somewhat more realistic use of Japanese forces than the KN basically sitting in port and doing nothing, which as we all know ain't happening. It doesn't call for the Japanese to mount any attacks that they didn't historically mount, it just has two of them taking place earlier while leaving the taking of Guam for the very near future, and without an airfield, Guam isn't really as important as Midway island.

Anyone got any thoughts or comments about this potential alternate "filling in the holes" type thing?

I bolded the relevant part
I am not sure if this option is inferior. We do not know how the USN would react to this.
Would they send out the intact battle line together with the carriers? If they do so, when would they send them out? In an attempt to retake Wake island (probably not)? Or perhaps guessing / spotting the IJN going for Midway in an attempt to stop them there? How would those engagements turn out? If the US loses the battleline and/or carriers in the open sea, the Japanese may be in a better position than in OTL.

 

[nbcman]

Prior to the PH raid, the only major attack on warships by planes was the Taranto raid by the RN (if you ignore the Bismarck hunt).
{snip}

The IJN had practice sinking various ROCN cruisers, destroyers, and smaller vessels in 1937. Ping Hai and Ning Hai were sank by planes flown off of Kaga as well as ground based aircraft per Combined Fleet:

22-23 September 1937:
NING HAI and PING HAI are attacked several times by aircraft from carrier KAGA and the ground-based 2nd Combined Air Flotilla. NING HAI sustains hits by four bombs and several near misses. PING HAI sustains hits by eight bombs and several near misses. Her captain is badly wounded, but continues the fight. PING HAI settles in shallow water near Koin. The Chinese shoot down several IJN aircraft and damage others.

 

[BlackDragon98]

Had the guys on USS Ward realized they were under attack after finding the midget sub, the fleet would have taken less damage.
All aircraft would have been scrambled, and ships and land batteries would be spewing flak.
Those Japanese paper airplanes would have been shredded.

 

[Draconis]

One possible POD that might have caused the Imperial Japanese command to concentrate all available forces on their Southern Resource Area attacks only is if they didn't receive the intelligence boon from the SS Automedon. https://www.forcez-survivors.org.uk/automedon.html

There is also a recent thread on this incident too. If the Japanese didn't have solid and convincing evidence of the weakness of the British defenses of Singapore and Malaya they may have dedicated more units, including the Kido Butai for the Malayan campaign. The Japanese considered the capture of Singapore crucial.

WI: KM Atlantis Never Captures SS Automedon

SS Automedon was carrying secret information pretty much containing the weaknesses of British positions in the Far East, and the capture of her secret cargo greatly aided the Japanese invasion. But what if Automedon was delayed a bit in leaving port, and she never encountered Atlantis?

www.alternatehistory.com