Lets stay put

[mcnutt]

What if 1940, the Pacific Fleet stays in San Diego? Japan will still go to war and bomb Pearl Harbor on December 7, 1941. They will attack fewer ships. The US has a fleet ready to fight Japan. How does World War II in the Pacific play out?

[lordroel]

Dec 5, 2016 19:54:46 GMT mcnutt said:

What if 1940, the Pacific Fleet stays in San Diego? Japan will still go to war and bomb Pearl Harbor on December 7, 1941. They will attack fewer ships. The US has a fleet ready to fight Japan. How does World War II in the Pacific play out?

not much difference as no carrier was hit during the pearl Harbor attack in OTL.

[stevep]

Guys

Actually,
a) If the bulk of the US fleet is still in San Diego then would the Japanese still attack Pearl Harbour? It was a risky operation and consumed a lot of resources which they could definitely use elsewhere. The only likely reason I can think form this is that they might attack what was there, i.e. things like the oil storage tanks and repairs facilities. If they did this AND it was successful that could seriously handicap USN operations in the Pacific until the damage was made good.

b) If they don't attack then there is one nasty complication. The USN still has its battleships and hasn't seen how devastating carrier a/c can be, although land based air while probably still have shown their effectiveness against Force Z. Hence they could continue with their existing doctrine, centred around the battle-fleet with the carriers being used singly and primarily as scouts, instead of being forced to concentrate on their carriers. This would limit their operations as the battle-fleet is a lot slower and also it would consume a lot of supplies and escorts for those ships. Furthermore if this force clashes with the Japanese main force then it could get a nasty shock from the Japanese CVs, with much heavier losses than at Pearl as ships sunk would go down in deep water rather than largely be refloatable and repairable.

It's very unlikely to greatly change the outcome of the war as the Japanese are hopelessly outclassed by their combined opponents but could change a lot of the early stages.

Steve

PS  There are two possible serious butterflies but their probably fairly unlikely options.
1)  That the lack of a clear threat from the US means that the Japanese don't attack the US but only the British and Dutch.  This could be seriously disastrous for the allied powers.

2)  That the US, with a complete battle-fleet is forced by political pressure to attempt a relief of the Philippines.  This would be likely to be a major disaster and IF also the Japanese haven't attacked Pearl with the resulting upsurge in war feeling in the states there is the outside chance that the US might see a move for peace with Japan.

[lordroel]

Dec 5, 2016 20:23:08 GMT stevep said:

Guys

Actually,
a) If the bulk of the US fleet is still in San Diego then would the Japanese still attack Pearl Harbour? It was a risky operation and consumed a lot of resources which they could definitely use elsewhere. The only likely reason I can think form this is that they might attack what was there, i.e. things like the oil storage tanks and repairs facilities. If they did this AND it was successful that could seriously handicap USN operations in the Pacific until the damage was made good.

b) If they don't attack then there is one nasty complication. The USN still has its battleships and hasn't seen how devastating carrier a/c can be, although land based air while probably still have shown their effectiveness against Force Z. Hence they could continue with their existing doctrine, centred around the battle-fleet with the carriers being used singly and primarily as scouts, instead of being forced to concentrate on their carriers. This would limit their operations as the battle-fleet is a lot slower and also it would consume a lot of supplies and escorts for those ships. Furthermore if this force clashes with the Japanese main force then it could get a nasty shock from the Japanese CVs, with much heavier losses than at Pearl as ships sunk would go down in deep water rather than largely be refloatable and repairable.

It's very unlikely to greatly change the outcome of the war as the Japanese are hopelessly outclassed by their combined opponents but could change a lot of the early stages.

Steve

PS  There are two possible serious butterflies but their probably fairly unlikely options.
1)  That the lack of a clear threat from the US means that the Japanese don't attack the US but only the British and Dutch.  This could be seriously disastrous for the allied powers.

2)  That the US, with a complete battle-fleet is forced by political pressure to attempt a relief of the Philippines.  This would be likely to be a major disaster and IF also the Japanese haven't attacked Pearl with the resulting upsurge in war feeling in the states there is the outside chance that the US might see a move for peace with Japan.

One question but that is a big if, instead of a Pearl harbor attack the Japanese Imperial Navy goes for a San Diego attack instead, would they have the capability to do this.

[stevep]

Dec 5, 2016 20:36:07 GMT lordroel said:

Dec 5, 2016 20:23:08 GMT stevep said:

Guys

Actually,
a) If the bulk of the US fleet is still in San Diego then would the Japanese still attack Pearl Harbour? It was a risky operation and consumed a lot of resources which they could definitely use elsewhere. The only likely reason I can think form this is that they might attack what was there, i.e. things like the oil storage tanks and repairs facilities. If they did this AND it was successful that could seriously handicap USN operations in the Pacific until the damage was made good.

b) If they don't attack then there is one nasty complication. The USN still has its battleships and hasn't seen how devastating carrier a/c can be, although land based air while probably still have shown their effectiveness against Force Z. Hence they could continue with their existing doctrine, centred around the battle-fleet with the carriers being used singly and primarily as scouts, instead of being forced to concentrate on their carriers. This would limit their operations as the battle-fleet is a lot slower and also it would consume a lot of supplies and escorts for those ships. Furthermore if this force clashes with the Japanese main force then it could get a nasty shock from the Japanese CVs, with much heavier losses than at Pearl as ships sunk would go down in deep water rather than largely be refloatable and repairable.

It's very unlikely to greatly change the outcome of the war as the Japanese are hopelessly outclassed by their combined opponents but could change a lot of the early stages.

Steve

PS  There are two possible serious butterflies but their probably fairly unlikely options.
1)  That the lack of a clear threat from the US means that the Japanese don't attack the US but only the British and Dutch.  This could be seriously disastrous for the allied powers.

2)  That the US, with a complete battle-fleet is forced by political pressure to attempt a relief of the Philippines.  This would be likely to be a major disaster and IF also the Japanese haven't attacked Pearl with the resulting upsurge in war feeling in the states there is the outside chance that the US might see a move for peace with Japan.

One question but that is a big if, instead of a Pearl harbor attack the Japanese Imperial Navy goes for a San Diego attack instead, would they have the capability to do this.

  Lordroel

  Short of ASB intervention or multiple years of planning and logistical build-up that it would be very difficult to hide the answer is no.  In terms of range alone Pearl was pretty much at the limits of their operations and I think some of their escorting destroyers had to be towed back to base as they ran out of fuel.  San Diego would be even further and even if they could get the range somehow they would probably have even greater difficulty approaching to within attack range without being detected.  Not to mention the risk, once the attack takes place of retreating all the way across the Pacific without being attacked, by air and subs if nothing else.

  Steve

[doug181]

I don't think they had enough oilers to get their fleet to San Diego

[mcnutt]

The Japanese would still attack Pearl Harbor ITTL. They have to do their best to destroy American power in the Pacific.

[lordroel]

Dec 6, 2016 2:48:43 GMT mcnutt said:

The Japanese would still attack Pearl Harbor ITTL. They have to do their best to destroy American power in the Pacific.

But their power is no based in San Diego, why attack Pearl Harbor.

[doug181]

Philippines the primary target on their flank to the East Indies,with fleet in San Diego,I think they pass on Pearl Harbor.

[lordroel]

Dec 7, 2016 13:35:33 GMT doug181 said:

Philippines the primary target on their flank to the East Indies,with fleet in San Diego,I think they pass on Pearl Harbor.

Could this means that the Japanese Decisive Battle Doctrine (艦隊決戦 Kantai Kessen?) would wok better if the United states Navy does not operate from Pearl Harbor, the Decisive Battle Doctrine was a naval strategy adopted by the Imperial Japanese Navy in which at a single stroke destroy an invading fleet as it approached Japan after suffering losses through attrition as it penetrated Japanese perimeter defenses.

[stevep]

Dec 7, 2016 15:59:53 GMT lordroel said:

Dec 7, 2016 13:35:33 GMT doug181 said:

Philippines the primary target on their flank to the East Indies,with fleet in San Diego,I think they pass on Pearl Harbor.

Could this means that the Japanese Decisive Battle Doctrine (艦隊決戦 Kantai Kessen?) would wok better if the United states Navy does not operate from Pearl Harbor, the Decisive Battle Doctrine was a naval strategy adopted by the Imperial Japanese Navy in which at a single stroke destroy an invading fleet as it approached Japan after suffering losses through attrition as it penetrated Japanese perimeter defenses.

  The USN will still work from Pearl, once the war starts.  There is the chance that the Japanese might get the chance to try their decisive battle doctrine if political pressure and the existence of a US battle-fleet means that the USN is driven into being more aggressive.  As I say the naval experts already agreed that the Philippines were indefensible but the politicians might not agree or they may be lured into a big battle somewhere else.  The Japanese carrier force used as a concentrated strike force could be a very nasty shock for the US and their older ships would be a lot slower to escape if they were forced to retreat.  Not going to decide the war in the longer run but could make for a much nastier defeat for the USN than Pearl was OTL.

[doug181]

Yes especially if the Japanese got our carriers early on the rest of fleet sitting ducks hindered by slow (21 knot)speed of old battleships.

[lordroel]

Dec 8, 2016 12:42:18 GMT doug181 said:

Yes especially if the Japanese got our carriers early on the rest of fleet sitting ducks hindered by slow (21 knot)speed of old battleships.

Why would that happen, the carriers most likely will operate as they did in OTL.

[stevep]

Dec 8, 2016 21:39:04 GMT lordroel said:

Dec 8, 2016 12:42:18 GMT doug181 said:

Yes especially if the Japanese got our carriers early on the rest of fleet sitting ducks hindered by slow (21 knot)speed of old battleships.

Why would that happen, the carriers most likely will operate as they did in OTL.

  Lordroel

  Not necessarily.  As I understand it the USN mainly viewed carriers as auxiliaries and scouts for the BB force and deployed them singularly in such roles.  It was only the lack of any alternative after Pearl [and with the war against Germany also typing up the remaining BBs to a degree] that meant they listened to ideas from the carrier commanders and had to base their operations around them.

  If the USN operated as I believe its doctrine dictated and made a major attack with the capital ships as the core of the force and the carriers operating singularly around the fringes they could get very roughly handled.  Especially given the elite status of the Japanese veterans, if they were also supported by land based a/c [say by a US attack on a Japanese base] and with the racial views of the early period of the conflict.

  As doug pointed out the US BBs are slow and if they have to withdraw they could take a long time running the gauntlet to get out of range.  Furthermore I think most were largely unmodified in terms of AA weaponry at the time.  Worst of all, if they did have to retreat would any surviving carriers use their speed to escape quickly or stay with the main fleet seeking to cover them?  Which means their likely to take the brunt of the Japanese attacks while their their.  Such a scenario could turn into a markedly worse disaster for the USN than Pearl simply because such losses would be in deep and hostile water.  Hence no hope of re-floating and repairing many of the ships and crew losses would be much higher.

  Its still not going to make a difference in the end with the huge material advantage the US will have in a couple of years, provided there's not a collapse in allied will, but it could be very messy for the USN and for the allied position in E Asian and the Pacific.

  Steve

[doug181]

I agree with Steve.Early war US AA was horrible.