Ok so seeing as today is the day of the attack I decided to whip up an alternate history scenario. The video below is more to set it up.
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What happens if due to better intelligence-gathering the United States knows about the attack on Pearl Harbor some time before it happens. So the loss of life is less and the number of ships hit is at best one or two with none of them being lost.
 
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Ok so seeing as today is the day of the attack I decided to whip up an alternate history scenario. The video below is more to set it up.
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What happens if due to better intelligence-gathering the United States knows about the attack on Pearl Harbor some three hours before it happens. So the loss of life is less and the number of ships hit is at best one or two with none of them being lost.

Wrong one this is pre 1900s ur should be in 1900 and after
 
So does anybody have any ideas on what the butterflies would be due to having better intelligence in a less devastating Pearl Harbor attack? I'm not planning on doing a timeline it's just a fun question.
 
So does anybody have any ideas on what the butterflies would be due to having better intelligence in a less devastating Pearl Harbor attack? I'm not planning on doing a timeline it's just a fun question.
Not much.

Its still a surprise attack, so it's still the Day that lives in Infamy, and so on.

It still puts the USN back on it's heels, so Singapore and so on still happens.

It doesn't affect the wave of Essex-class about to come out.

It doesn't effect the USN not wanting to save the US Army in the Philippenes.

So, not much ...
 

ScrewySqrl

Kicked
Bad news is the US keeps it's obsolete battleship force intact. This might have be consequences later if the us fails to realize carries are now the better platform
 
Not much.

Its still a surprise attack, so it's still the Day that lives in Infamy, and so on.

It still puts the USN back on it's heels, so Singapore and so on still happens.

It doesn't affect the wave of Essex-class about to come out.

It doesn't effect the USN not wanting to save the US Army in the Philippenes.

So, not much ...
So you think knowing hours before that the Japs are going to attack isn't going to have butterflies. In OTL we knew an attack was possible and word was even sent to Pearl Harbor. It came after the attack but we at the very least expected at least a possible attack. ITTL we know and get planes in the air and move the ships out to sea. That should at least do something. Sure December 7th, 1941 is still a day that lives in infamy but for a whole new reason. It being the fact the Japs tried to pull a fast one on us and failed.
 
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Three hours warning isn't a lot. Many ships will still be in the harbor, some ships will get caught just leaving the harbor and will get sunk in deep water and be unsalvageable. Lots of damage to the base facilities. The biggest change will be the severity of Japanese losses. With fighters in the air and AA batteries manned, the Japanese will lose over a hundred planes instead of just 39. Hard to say if any land based bombers will be able to find and hit the Japanese carriers, but there is the possibility. I see no major change in the course of the war, but the Japanese lose a little quicker.
 
Three hours warning isn't a lot. Many ships will still be in the harbor, some ships will get caught just leaving the harbor and will get sunk in deep water and be unsalvageable. Lots of damage to the base facilities. The biggest change will be the severity of Japanese losses. With fighters in the air and AA batteries manned, the Japanese will lose over a hundred planes instead of just 39. Hard to say if any land based bombers will be able to find and hit the Japanese carriers, but there is the possibility. I see no major change in the course of the war, but the Japanese lose a little quicker.
Ok, so I edited the first post so it has no set time being given. It could be a day, a week, or as you say a few hours. The POD is just that the attack is discovered in word of the upcoming attack is wired to Pearl Harbor
 
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GarethC

Donor
So does anybody have any ideas on what the butterflies would be due to having better intelligence in a less devastating Pearl Harbor attack? I'm not planning on doing a timeline it's just a fun question.
It's been covered on a few other threads.
Broadly, there's an awful lot of room for authorial fiat, particularly with regard to how much better the intelligence is.

With a day or more of warning, the Pacific Fleet isn't caught at anchor. It may move to engage Kido Butai, which I think is the consensus likely outcome, in which case it is attacked under weigh and takes fewer losses as maneuvering ships are harder to hit, but those that are sunk are lost in deep water and cannot be refloated as OTL, plus the loss of life is significantly higher and those crews are not available for the USN as new construction comes online. If the fleet is judged by Kimmel for whatever reason not to be in fighting trim and moves to the SE of Pearl away from KB, then it is not spotted at all and takes no losses. While at sea, the USAAF is not used to coordinating a CAP with the Navy, so there is significant chance that something will go badly wrong and any KB strike is not intercepted.

If there's some warning but still not enough to get steam up - say, Ward rams a midget submarine and has wreckage to prove it - then there's an attack into ready defences.
If the Hawaiian Air Force does manage to scramble and engage the attacking first wave, it has a lot more fighters than the IJN does; however, only hours later Manila will be bombed despite three pursuit groups being scrambled under radar control to intercept the incoming raid because the USAAF isn't very practiced at ground-controlled intercept, so the actual strikes may go in undisturbed by US CAP. On the one hand, the US has less agile fighters and doesn't have a doctrine of boom-and-zoom. On the other, quantity has a quality all its own. Either way, if Fuchida sees fighters in the air, the second wave will be called off and the attack aborted. Probably. Readed AAA is still not great in 1941 with too many ships reliant on 1.1" or .50 cal, not enough radar, no VT fuses, and nowhere near the profusion of light AA found on USN vessels by the late war. IJN losses will be heavier, especially among the torpedo bombers, but not catastrophic.

It's B-17s that can find KB most easily, but they will all miss.

If intelligence is really good (though I am not sure how without ASB intervention), the USN ambushes KB before dawn with heavy surface units while the strike is still being fuelled. The US battleline massively outguns the two refitted BCs, and the cruisers are faster than Nagumo's carriers. While the Long Lance torpedoes are scary, fundamentally it probably ends like S&G vs Glorious writ large, and Japan has lost the Pacific War before the first shots in the Philippines are fired.

Butterflies - if it all ends in a wash, there aren't that many. The USN lacked oilers for its battleline to operate over the distances of the Pacific at the time anyway - they are still largely stuck at Pearl for the moment. Greater Japanese aircraft and pilot losses are not going to slow operational tempo much. PoW and Repulse probably are still lost, as are Singapore, the Philippines, and Burma.
 
Upside, given even an hour's warning, ships that cannot leave their moorings have time to close water-tight doors, man AAA, prepare 'damage control' rather than react 'ad-hoc'.
Downside, as stated above, nimble ships that *do* leave their moorings may be sunk in the channel or deeper water. Former risks blocking channel, latter probably total loss and higher casualties than OTL. Against that, having a bunch of light escorts outside harbour with AAA would make things lively, perhaps throw off attackers' aim beyond the 'ducks in a barrel' they found...

Could USAF air-base(s) sortie enough fighters to hurt the IJN aircraft ? I don't know their pilot & ground-crew alert / recall rating, but I doubt much could be done. Still, every little helps.

Big butterfly, as I see it, is the 'absent' USN carriers. Would they have time to get their recon aircraft out and spot those IJN carriers ? I doubt USN could muster a full-on air-strike, but any damage to IJN flight-decks, be they empty or crowded, any culling of returning aircraft will so hurt. Also, if the IJN carriers must zig-zag to avoid attack, so cannot 'turn into wind', a lot of returning aircraft would have to 'ditch'. Even if the IJN carriers get away, their crippled air-wings leave them horribly vulnerable...
 
It seems that the overall consensus is that the Japanese would lose the war a little bit quicker than in our timeline. So a follow-up question would be how would the world as a whole react to this failed attack? Surely the IJN would review their plans after losing more of their air forces and naval force. If the war ends sooner would we even deploy the use of the two nukes? If we still do so the only choice in my eyes is Nazi Germany. I can't see that being viewed favorably.
 
It seems that the overall consensus is that the Japanese would lose the war a little bit quicker than in our timeline .........If the war ends sooner would we even deploy the use of the two nukes? If we still do so the only choice in my eyes is Nazi Germany. I can't see that being viewed favorably.
Since this war is shorter.....how does they get them ready before the end?
 
Since this war is shorter.....how does they get them ready before the end?
A shorter war isn't going to stop the United States from producing nuclear weapons. I don't see how a failed attack on Pearl Harbor is going to derail the Manhattan Project from being a thing. Just because the forces of Imperial Japan are defeated sooner that doesn't mean that we would have defeated Nazi Germany or the fascist Italians. Likely we would have but not a certainty. Thus why I asked would we even deploy the nukes. We could just keep it under wraps and blast the reds if they try anything. By that point, we would have hundreds of the things and better yet the yields wouldn't be just 15 or 20 kilotons but likely far higher. Possible in the 100 kiloton range.
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Looking at this in just five years the Us goes from just two nukes to nearly 300 which is when I would guess would be when we may have a need to show them off.
Nuclear weapons stockpiles


U.S. and Soviet/Russian nuclear weapons stockpiles/inventories from 1945 to 2006. The failing Soviet economy and the dissolution of the country between 1989-91 which marks the end of the Cold War and with it the relaxation of the arms race, brought about a large decrease in both nation's stockpiles. The effects of the Megatons to Megawatts can also be seen in the mid-1990s, continuing Russia's reducing trend. A similar chart focusing solely on the quantity of warheads in the multi-megaton range is also available.[1] Moreover, total deployed US & "Russian" strategic weapons increased steadily from the 1980s until the Cold War ended.[2] Graph of nuclear testing by year and country.Global nuclear weapons stockpiles (1945–2025)[3]


Country19451950195519601965197019751980198519901995200020052014Projections[4]
United States United States22992,42218,63831,14926,00827,51923,36821,39210,90410,5778,3607,7007,2603,620 (for 2022)[5]
Soviet Union Soviet Union
Russia Russia
052001,6056,12911,64319,05530,06239,19737,00027,00021,50017,0007,5005,350 (for 2022)[4]
United Kingdom United Kingdom001442436394492492422422422281281215180 (for around 2025)[6]
France France00003236188250360505500470350300
China China0000575180205243232234232235260150-220 (for 2020)[7]
Israel Israel000008203142536372808065-85 (for 2020)[7]
India India0000000[8]1[8]3[8]7[8]14[8]28[8]4490-11050-70 (for 2020)[7]
South Africa South Africa00000000[8]3[8]6[8]0[8]0000[7]
Pakistan Pakistan000000000[8]4[8]13[8]28[8]38100-120150-200 (for 2021)[9]
North Korea North Korea000000000[8]0[10]-1[8]0[10]-2[8]0[10]-2[8]8[8]6-8
Kazakhstan Kazakhstan0000000001,410 (1991)[11]00000
Ukraine Ukraine0000000002,321 (1991)[12]00000
Belarus Belarus000000000At least 81 (1991)[13]00000
Worldwide total23042,63620,28537,74138,16447,45454,40961,662~51,86438,823 - 38,825
30,971 - 30,97325,73615,811 - 15,853
 
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Here's a thought: What if the Kido Butai attack force simply...fails to find Pearl Harbor? Be off by a couple of degrees on navigation, and they miss Hawaii altogether. Maybe they find it anyways and attack, but have to ditch, or maybe they have to drop ordinance and try to return...though I don't know if the pilots would do that, or simply continue looking until they run out of fuel.
 
Here's a thought: What if the Kido Butai attack force simply...fails to find Pearl Harbor? Be off by a couple of degrees on navigation, and they miss Hawaii altogether. Maybe they find it anyways and attack, but have to ditch, or maybe they have to drop ordinance and try to return...though I don't know if the pilots would do that, or simply continue looking until they run out of fuel.
Your talking about a people who flew planes into ships as a way of war. I could easily see them flying their planes until they drop out of the sky like stones in water. While that would help in a failed attack I think it's best if the only thing that's different to our history is foreknowledge of the attack. Let's say a week beforehand. I'm not sure how plausible a week's warning is but any more and I feel I would be entering into ASB level and I don't want that for this post.
 
So you think knowing hours before that the Japs are going to attack isn't going to have butterflies. In OTL we knew an attack was possible and word was even sent to Pearl Harbor. It came after the attack but we at the very least expected at least a possible attack. ITTL we know and get planes in the air and move the ships out to sea. That should at least do something. Sure December 7th, 1941 is still a day that lives in infamy but for a whole new reason. It being the fact the Japs tried to pull a fast one on us and failed.
Honestly, that's almost the worst possible outcome. That's enough time for the fleet to put to sea where they can be bombed and torpedoed and sink in deep water where they're not recoverable and all those highly trained crewmen are lost. Yeah, the level bombers with the converted 16" shells won't hit shit, but the Vals will and the Kates will.

The IJN will lose a lot more planes than they did historically. The second wave reported flying into a wall of steel and lead. The first wave will now experience this as well. Plus the USAAF will get some kills out of the deal. This will have long term repercussions on the IJN as their naval aviation goes into an earlier death spiral.

Enterprise will likely try and join up with the fleet when they sortie. If they link up before the attack comes in, she could be lost as well. If it's after, Halsey likely launches his own strike on the Kido Butai, followed shortly after by Lexington. This scenario could get ugly for both sides.
 
Here's a thought: What if the Kido Butai attack force simply...fails to find Pearl Harbor? Be off by a couple of degrees on navigation, and they miss Hawaii altogether. Maybe they find it anyways and attack, but have to ditch, or maybe they have to drop ordinance and try to return...though I don't know if the pilots would do that, or simply continue looking until they run out of fuel.
Bit difficult I'd say since they were litterally 'homing' in on Radio broadcasts out of the islands :)

Your talking about a people who flew planes into ships as a way of war. I could easily see them flying their planes until they drop out of the sky like stones in water. While that would help in a failed attack I think it's best if the only thing that's different to our history is foreknowledge of the attack. Let's say a week beforehand. I'm not sure how plausible a week's warning is but any more and I feel I would be entering into ASB level and I don't want that for this post.
Eh? You're making an assumption based on the later war for the begining of the war. Those pilots knew quite well that they were a limited and valuable resources and it was not until Japan was desperate that they were thrown away like that. Had they reached a point where they had enough fuel to get back to the KB and not yet found the target, (and again THAT in and of itself is border-line ASB due to all the wonderful radio traffic out of Hawaii) they would have returned to the KB. They never would have reached a point of no return under the circumstances.

Having said that, had they reached such a point AND still been able to reach PH it's likely they would have gone in anyway and then tried to make it back to the KB with the 'hard' call' being if he KB moves towards Hawaii to assist or leaves them to their fate. (IJNHQ had gamed out over 50% losses being 'acceptable' if more than 50% of the scheduled targets were hit. It's not like everyone in the KB were not aware of the odds)

Something to keep in mind about the idea of "warning" is the US actually DID know that an attack was coming but no one really expected the IJN to be able to hit PH and they certainly didn't expect it to be an air attack.

Randy
 
A bit difficult I'd say since they were literally 'homing' in on Radio broadcasts out of the islands :)



Eh? You're making an assumption based on the later war for the beginning of the war. Those pilots knew quite well that they were a limited and valuable resources and it was not until Japan was desperate that they were thrown away like that. Had they reached a point where they had enough fuel to get back to the KB and not yet found the target, (and again THAT in and of itself is border-line ASB due to all the wonderful radio traffic out of Hawaii) they would have returned to the KB. They never would have reached a point of no return under the circumstances.

Having said that, had they reached such a point AND still been able to reach PH it's likely they would have gone in anyway and then tried to make it back to the KB with the 'hard' call' being if he KB moves towards Hawaii to assist or leaves them to their fate. (IJNHQ had gamed out over 50% losses being 'acceptable' if more than 50% of the scheduled targets were hit. It's not like everyone in the KB were not aware of the odds)

Something to keep in mind about the idea of "warning" is the US actually DID know that an attack was coming but no one really expected the IJN to be able to hit PH and they certainly didn't expect it to be an air attack.

Randy
I know that we had some idea that such a thing was possible I even said so in one of the posts above. Now as for making an assumption you may have a point there but they did do that and would likely do so sooner in this timeline seeing as their loss of pilots and planes will be substantially higher than OTL. Then again maybe the Japanese see sense and capitulate before that madman of an idea even enters into any war room plans. It is after all kind of stupid to be throwing away one of your most valuable assets your pilots and airwing.

With that said let's say the worst possible outcome happens what would that do to the US war effort? If I had to guess we pour more manpower into the pacific theatre of the war than the European one. This I would think would have a few knockback effects in the war. Hell, the invasion of Normandy might even fail, if it even happens at all.
 
I know that we had some idea that such a thing was possible I even said so in one of the posts above. Now as for making an assumption you may have a point there but they did do that and would likely do so sooner in this timeline seeing as their loss of pilots and planes will be substantially higher than OTL. Then again maybe the Japanese see sense and capitulate before that madman of an idea even enters into any war room plans. It is after all kind of stupid to be throwing away one of your most valuable assets your pilots and airwing.
Just making sure we're on the same page :) in actuality running yourself out of ammo and then diving into the nearest 'target of opportunity' isn't just a "Japanese" thing as everyone did it if you weren't likely to get home again. It depended on the actual situation though and in this case..

Not so clear as of yet since at this point the Japanes are also not victims of "winning" either so the idea (as they understood it for the most part) was this would be a 'knockout' blow that would force the US into a negotiated peace. So ditching and/or crashlanding in/near Hawaii would be a possible option. (It wasn't until the a bit later and all the American loses and surrenders made them more akin to the "Chinese" in the military's mind than previously that things really went downhill)

It was litterally the point where even the most gung-ho Japanese military mind could no longer deny that some sort of defeat was ineveitable, (and after HQ had essentially 'written-off' even the Philippians, let alone Okinawa) that the Japanese made "kamikaze" a directive.

Capitulate? Now there's a word that wouldn't enter thier minds even with US forces storming ashore on the Home Islands and frankly they TRIED to avoid that going as far as planning on kidnapping the Emperor to do so. No the "madness" was baked into the war from the start, which is why they were "planning" on loosing more than half the KB air fleet as the standard case of attacking PH.

Even prepped and ready for bear the US fleet would have been hurt, given enough time it would be at sea but that's likely worse rather than better.

Now if we were to assume a more aggressive US patrolling, (credible warning of a strike on PH is pretty hard to get though since as we've noted it was thought to be beyond the IJN capability, and it technically was after all) that forces the KB to abort the strike that's a whole 'nother thing. Short of that the KB was going to launch the strike as it was a requirement in the plan to try and force the US to negotiate. And once that point is reached you'll probably have at least two wave and even if the KB loses a few carriers that's an acceptable price to pay.

With that said let's say the worst possible outcome happens what would that do to the US war effort? If I had to guess we pour more manpower into the pacific theatre of the war than the European one. This I would think would have a few knockback effects in the war. Hell, the invasion of Normandy might even fail, if it even happens at all.
Keep in mind that FDR had already set up the "Europe first" planning by this point. The worst outcome? You've already hit it:
The US knows the blow is coming and moves the fleet to San Diego, so even if the KB follows through they hit nothing really significant. More likely with that much warning and it's taken credibly then the USN is more pro-active and aggressive which means the KB is likely spotted and retreats without striking. (Which would throw Japanes plans into the waste basket somewhat but now they have to plan and execute the "Decisive Battle" stratgey in the Philippians, which may or may not be something the USN is willing to participate in) With an intact US Battleline, (even as mostly outdated as it was) FDR is going to have to deal with the one thing he did NOT want to deal with which was supporting a two front war. He's already commited to Europe first, (and with good reason) but having mostly intact assets in the Pacific is going to probably force the USN (due to public pressure) into fights they'd rather avoid with all that entails. But while it might be a bit harder to sell Europe First it's still going to be THE plan so I doubt that even a failed raid is going to derail the main planning.

Where it gets tricky is public pressure to 'do' something about the Philippians which could be handing the Japanese the "Decisive Battle" they always wanted.

Randy
 
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