Pearl Harbor the unfought battle

[CT23]

http://www.amazon.com/Harbor-unfoug...1-1&keywords=pearl+harbor+the+unfought+battle


The scenario is based off this book^.

What if Kimmel and others found out about Japanese spies at Pearl Harbor and prepared better defenses?

 

[Germaniac]

There's been allot of speculation but I'm of the opinion it wouldn't have ended well for the us navy. The Japanese would have the air power while the battleship's are going to be going after their Japanese counterparts. The only thing comparable is the British taskforce from Singapore and we all know how well that ended for the battleships.

 

[Anaxagoras]

If the battleships had been sunk at sea, they wouldn't have been salvageable later on.

 

[BMN]

Plus if the carriers are with the battleships in their battle-group, then the carriers get caught as well. Things go much worse for the U.S. from there.

 

[Carl Schwamberger]

Admiral Kimmels war plan is available on the net.. If I remember I'll link to it next week. In it there is nothing about charging out to fight the Japanese fleet. If it were known the IJN was approaching Oahu the intent was to remove the fleet to the SE of the Hawaiian islands & harras the enemy with the land based aircraft on Oahu. It had been directed that the US Army had responsibility for defending the Hawaiian islands and the USN would support that, but also preserve its strength for later offensive action.

If the opportunity to ambush the enemy fleet presented itself the the US fleet might have struck, but Kimmels written plan makes it clear that risks would not be taken.

The USN had been studying the problem of a Pacific war for over twenty years. War Plan Orange dated back two decades. Fairly early in that examination it was concluded that any early offensive action carried a high risk of defeat. The winning strategy as seen as as waiting twelve to eighteen months until the US fleet obtained the logistics support and new ships necessary to take the offence.

Kimmels plan, or any of the previous war plans did include raids, and acting on opportunities during this waiting period, but they emphasized the avoidance of risk.

As for the IJN attacking a alerted Pearl Harbor. OTL they lost 28-29 aircraft as inoperable. Thats roughly a ten percent loss a after a suprise attack. How badly damaged after fighting through a prepared defense is the Japanese carrier air wing liable to be?

 

[RamscoopRaider]

Admiral Kimmels war plan is available on the net.. If I remember I'll link to it next week. In it there is nothing about charging out to fight the Japanese fleet. If it were known the IJN was approaching Oahu the intent was to remove the fleet to the SE of the Hawaiian islands & harras the enemy with the land based aircraft on Oahu. It had been directed that the US Army had responsibility for defending the Hawaiian islands and the USN would support that, but also preserve its strength for later offensive action.

If the opportunity to ambush the enemy fleet presented itself the the US fleet might have struck, but Kimmels written plan makes it clear that risks would not be taken.

The USN had been studying the problem of a Pacific war for over twenty years. War Plan Orange dated back two decades. Fairly early in that examination it was concluded that any early offensive action carried a high risk of defeat. The winning strategy as seen as as waiting twelve to eighteen months until the US fleet obtained the logistics support and new ships necessary to take the offence.

Kimmels plan, or any of the previous war plans did include raids, and acting on opportunities during this waiting period, but they emphasized the avoidance of risk.

As for the IJN attacking a alerted Pearl Harbor. OTL they lost 28-29 aircraft as inoperable. Thats roughly a ten percent loss a after a suprise attack. How badly damaged after fighting through a prepared defense is the Japanese carrier air wing liable to be?

That was better than how I was going to say it

Also doesn't Nagumo have orders to turn back if discovered before a certain point?

If so then an increased readiness means more patrols and may mean the Kido Butai gets caught early enough for them to withdraw, unless I am misinterpreting things

 

[Anaxagoras]

Admiral Kimmels war plan is available on the net.. If I remember I'll link to it next week. In it there is nothing about charging out to fight the Japanese fleet. If it were known the IJN was approaching Oahu the intent was to remove the fleet to the SE of the Hawaiian islands & harras the enemy with the land based aircraft on Oahu. It had been directed that the US Army had responsibility for defending the Hawaiian islands and the USN would support that, but also preserve its strength for later offensive action.

If the Japanese struck at Pearl Harbor and the American fleet had withdrawn to the southeast of the islands, they would have taken losses from land-based defenses and carrier aircraft without damaging the American ships. Since they were at the end of their logistical tether, they would not have been able to maneuver all that much during their return voyage to Japan, allowing the Americans to launch a counter attack with a decent prospect of inflicting significant damage.

 

[Carl Schwamberger]

That was better than how I was going to say it

Also doesn't Nagumo have orders to turn back if discovered before a certain point?

If so then an increased readiness means more patrols and may mean the Kido Butai gets caught early enough for them to withdraw, unless I am misinterpreting things

There are other better equipped than I on this question. Nagumos guidance or orders were to damage the US fleet, not just attack PH. This was all tied somehow to not starting a battle before the DoW was delivered.

If the Japanese struck at Pearl Harbor and the American fleet had withdrawn to the southeast of the islands, they would have taken losses from land-based defenses and carrier aircraft without damaging the American ships. Since they were at the end of their logistical tether, they would not have been able to maneuver all that much during their return voyage to Japan, allowing the Americans to launch a counter attack with a decent prospect of inflicting significant damage.

Maybe. It depends on how much warning there is. The US carriers had been sent on their Wake reinforcement mission on Thursday I think. That mission reduced their combat capability, so OTL they were not well prepared for a battle. The US BB were too slow to catch Nagumos group if they started from SE of Hawaii. If there is a weeks worth of warning then a line of submarines could be deployed, and the US fleet might contemplate a ambush or pursuit. However war games played out by the USN in the 1920s and 1930s showed how difficult this sort of operation could be, and the risks involved. USN strategy for WPO and the more recent Rainbow Plans revolved around fleet preservation. The long term strategy was to crush Japan with a deliberate and massive blow, not some sort of quick & clever ju jitsu move that might fail.

There is of course the wet dream scenario, where Admiral Pyes battle line lying to the west of Nagumo opens fire on the sillouetted carriers exactly at dawn with the decks packed with aircraft. While to the rear Halsey is ready to launch his own strike, and the US Army aircraft are forming up over Oahu.

 

[Cryhavoc101]

http://www.amazon.com/Harbor-unfoug...1-1&keywords=pearl+harbor+the+unfought+battle


The scenario is based off this book^.

What if Kimmel and others found out about Japanese spies at Pearl Harbor and prepared better defenses?

Basically a warned US Navy is going to sortie and 'NOT' blunder blindly around the pacific waiting to be sunk at sea, but with draw to the East within Land based air cover range, Rendezvous with the Carriers while maintaining a land based CAP and await developments.

Meanwhile any attempt at attacking an Alerted Pearl will result in heavy losses

However unless the US do to the Japanese Spies what the British did to the German ones and effectively sucker the Japanese high command into attacking, then word of the fleet will get back to the Japanese strike force and they too would with draw.

Japan and the US are already at war at this point - the message from the Embassy already decoded before the attack but word reaching Pearl too late to impact the readiness of the defenders.

What happens after that???

As for Sinking battleships at sea several points

The POW and Repulse with 4 destroyers were attacked by 88 'Land based' Aircraft and had no air cover of their own.

An alerted US Fleet having sortied would have had at least 8 Battleships, 8 or more Cruisers, 3 Fleet Carriers, 50 Destroyers and a couple of hundred land based fighters (in addition to their own carrier fighters) with which to oppose the Japanese carrier forces attempts to attack them.

Its a lot harder to hit and sink a ship at flank speed, closed up at battle stations with air cover vs one tied up along side with the crew doing anything but being at action stations.

The British Navy discovered in 1940 that even a handful of planes would seriously disrupt a large attack on a fleet.

What would have happened at Pearl by the morning of the 7th had the US had proper prior warning is that the US Fleet would have regrouped east of the Island and the various organisations stood to.

Japanese "Spies" (assuming they had not been turned or replaced in this ATL) would have reported this to Japan and I am absolutely confident Nagumo would bottle it in keeping with the IJN's doctrine of conservation of fleet strength over a now risky attack and return the fleet to Japan.

 

[Carl Schwamberger]

One thing I am certain of; we would be debating what would happen had the IJN achieved suprise @ PH, catching the US fleet docked and hung over, with only 25% of crew on watch, the USAAF having no CAP aloft, and ammo for the AA guns locked up. Seems ASB doesn't it? How could such a thing occur?

Getting back to when the alert comes. It took a BB about four hours to come to operating steam from the single boiler 'housekeeping' condition they were in. The Nevada was changing boilers that morning and had two operating, so it was able to get underway in less than a hour. After reaching navigating power it took a ship over a hour to clear the harbor & channel outside. Clearing fifty plus ships overnight is in theory possbile, but odds are a number of destroyer, auxillaries, and the odd cruiser & BB would be left behind. If the warning comes anytime after midnight more ships would be caught inside the harbor.

 

[Cryhavoc101]

One thing I am certain of; we would be debating what would happen had the IJN achieved suprise @ PH, catching the US fleet docked and hung over, with only 25% of crew on watch, the USAAF having no CAP aloft, and ammo for the AA guns locked up. Seems ASB doesn't it? How could such a thing occur?

Getting back to when the alert comes. It took a BB about four hours to come to operating steam from the single boiler 'housekeeping' condition they were in. The Nevada was changing boilers that morning and had two operating, so it was able to get underway in less than a hour. After reaching navigating power it took a ship over a hour to clear the harbor & channel outside. Clearing fifty plus ships overnight is in theory possbile, but odds are a number of destroyer, auxillaries, and the odd cruiser & BB would be left behind. If the warning comes anytime after midnight more ships would be caught inside the harbor.

So long as the ships are closed up for action stations etc and moving with a friendly cap covering the fleet then chances are that the attack either gets called off as soon as the IJN learns that the US Navy is ready for them or they attack inflicting less damage and suffering heavier losses to AAA and the CAP.

Certainly there are a number of ships unable to steam or in dry dock etc but "The Fleet" would have sortied and the airfields alerted etc (no planes lined up for destruction)

That's the important thing here - the USA Knows its at war and IJN's biggest asset surprise is lost.

Also Patrol AC would be out searching for the Japanese fleet and if found would be subject to the attentions of a land based aircraft response.

 

[CalBear]

These are the actual instructions given to Nagumo, based post war U.S. investigation/interrogation/document recovery ( taken from the USSBS - Pacific)

In accordance with instructions from CinC Combined Fleet, the Task Force sortied from Hitokappu bay at 0600, 26 November and proceeded along the track shown in Appendix 2. On 2 December instructions were received to the effect that negotiations had failed and that 8 December was designated as "X"-day. The refueling was successfully completed on 3 December without mishap. (In the event of failure of the fueling operation it had planned to continue without the destroyers.) After refueling, the Task Force proceeded along the track without incident. No shipping was encountered and the force successfully escaped detection. During the approach, the following instructions were in effect:
If discovered prior to "X"-minus-2-day, the Task Force was to return to Japan without executing the attack.
If discovered prior to "X"-1-day, the decision as to what action to take was the responsibility of the Task Force Commander.
--15--
If discovered on "X"-minus-1-day or the morning of "S"-day the Task Force was to continue with the attack.
If at any time during the approach to Pearl Harbor the negotiations with the United States had been successful the attack would have been cancelled.
If, at any time during the approach to Pearl Harbor the American Fleet attempted to intercept the Japanese Task Force, the Japanese planned to counterattack. If the American Fleet advanced into Japanese home waters in pursuit of the Task Force it was planned to commit the Main Body of the Japanese Fleet as a support force.
If, after arriving in Hawaiian waters, it was found that the American Fleet was at sea and not in Pearl Harbor, the Japanese planned to scout a 30-miles radius around Oahu and attack if contact was made; otherwise they were to withdraw.

I have bolded the most relevant portions. It is important to keep in mind that the Kido Butai sent float planes to both Pearl Harbor and Lahaina anchorage site (off Maui) early in the morning of December 7th (neither of which were detected) to ensure that the fleet was still present. The Japanese had no interest in trying to hit just the air fields. No fleet = dry hole and the Kido Butai withdraws

 

[Carl Schwamberger]

... the Kido Butai sent float planes to both Pearl Harbor and Lahaina anchorage site (off Maui) early in the morning of December 7th ...

If I understand the USN habit of 1941 the Lahania anchorage had not been used much that year, & was not the standby station for a deployed fleet.

 

[CalBear]

If I understand the USN habit of 1941 the Lahania anchorage had not been used much that year, & was not the standby station for a deployed fleet.

It wasn't, but the location was a known one for the fleet to use as a gathering spot, so scouting it was common sense.