A defense of Husband E Kimmel

CalBear

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The Japanese aircraft never found the fleet. The Japanese battle orders were specific, if you don't find the carriers in port, cruisers and battleships were to be the target, if the entire fleet is absent, you will search out for 30 miles around Oahu. Kimmel had been headed more or less straight away from Pearl for six hours by the time the Japanese realized the bird had flown. He was well outside the search radius, by more than 40 miles, the Vals & Kates never found him (the fleet, in any case, would have been outside of the practical combat radius of the Val even if it had been located, by 0900).

The Japanese ITTL went after the base and whatever ships were still there. The Pennsylvania was pounded into scrap in the drydock, while the heavy cruisers San Francisco & New Orleans both of which were undergoing engine overhaul and unable to sortie were sunk (as noted in the original text, the San Francisco was determined to be lost beyond practical repair). The Curtis, Tangier, Dobin, Solace, Utah, Vestal, and Pelias all of them critical support ships, were all sunk or severely damaged.

TOTAL Japanese aircraft losses were 170. This included ~70 aircraft that were determined to be hors de Combat due to AAA damage and pushed over the side. The Japanese lost just over 110 pilots, including those who were disabled or died of wounds after getting back to the boat. Both the lost over the target and scraped after return to the fleet figures seem reasonable based on the really robust AAA surrounding the Pearl Harbor base complex, U.S. Army defenses included 26 fixed 3" AAA, 60 mobile 3" AA, 20 single mount 37mm AAA and 107 .50 AAA machine guns as well as the main shore defense guns for anti-ship defense, with this being augmented by two Marine Shore Defense Battalions with a total of 24 radar directed 90mm AAA (8 3 gun batteries), 38 single mount 40mm AAA, 56 single mount 20mm AAA and an additional 70 .50 cal AAA heavy machine Guns.)

Throw in the fact that the American fighters would have outnumbered the Japanese fighters around 3-1 (99 P-40 & 39 P-36 or 135 vs. 45 Zeros in the 1st wave) allowing at least 30-40 fighters a straight shot at the attack aircraft and also, not incidentally, removing the flak suppression strafing called for in the Japanese plan of attack.

All told it was a very, very bad day for the USN, with losses beyond those experienced IOTL and a much worse one for the IJN (although the scope of Japanese losses would not be known to the U.S. until the end of the war and are within those envisioned for the attack).
CalBear, I don't think it's specifically stated, but were the losses of the force that Kimmel set sail with limited to those two battleships?

If so, then that's a signficantly better outcome for the US than historical, and much, much moreso when you add the 170 Japanese aircraft shot down.

Not being able to replace trained air crew was a significant shortcoming of the Japanese war machine, and nearly every single one of the pilots of those lost aircraft would be either dead or captured.

Assuming only the two battleships were sunk by that submarine (unlikely, as others have pointed out), the aircraft losses the Japanese suffered also mean that the damage they would have inflicted (even if the fleet had not sailed) would be substantially less.

If only two battleships were sunk at sea, then I don't think the US commanders - in particular Kimmel - would have been overly criticised. Even if Kimmel headed south-east, the intention of getting his ships out to sea and away from an impending air strike would be seen in hindsight to have been a smart move.
 
TOTAL Japanese aircraft losses were 170. This included ~70 aircraft that were determined to be hors de Combat due to AAA damage and pushed over the side. The Japanese lost just over 110 pilots, including those who were disabled or died of wounds after getting back to the boat. Both the lost over the target and scraped after return to the fleet figures seem reasonable based on the really robust AAA surrounding the Pearl Harbor base complex, U.S. Army defenses included 26 fixed 3" AAA, 60 mobile 3" AA, 20 single mount 37mm AAA and 107 .50 AAA machine guns as well as the main shore defense guns for anti-ship defense, with this being augmented by two Marine Shore Defense Battalions with a total of 24 radar directed 90mm AAA (8 3 gun batteries), 38 single mount 40mm AAA, 56 single mount 20mm AAA and an additional 70 .50 cal AAA heavy machine Guns.)

Taking the higher totals from your list and the PHA listings, I make the A-A defences to be something like this:
On ships...........5"........232
On ships.............3".........135
On ships.........40mm.........1
On ships............1.1"........64
On ships.........50 Cal......397
Base… …………….5.5"……….18
Base………………3"………….110
Base……………..20mm………56
Base………..……37/40mm………63
'Base………..……50 Cal………214

Using this somewhat arbitrary AA point system
5” – 6 points
3” - 3 points
40/37mm – 9 points
20mm/1.1” – 3 points
50 Cal – 1 point.


That's roughly 3782 points of anti-aircraft on the OOB historically.


In your story the US Navy has gone to sea and Kimmel is not found. So the torpedo bombers and level bombers of the 1st wave will not attack Oahu, rather, they branch out and search for Kimmel at sea and then apparently not find him, (sorry if I'm wrong on that detail). They are therefore not engaged by anti-aircraft or defending fighters. Most of the American A-A guns (2395 points of 3782) are on the ships that have left Oahu and therefore are not present for the air raid. Say 80% of the ship-carried A-A leaves the harbor and 20% remains. That’s maybe 1,900 A-A points in your scenario vs. the 3782 points from the historical raid. Even allowing for quickly sunken ships and the sluggish army response, the practical A-A values should be no more than about half of the historical 2nd wave, which killed about 9 aircraft by AA.

At Midway Island for the 4 June 1942, raid – 6x5”, 24x3”, 8x40mm, 18x20mm, 90x50-cal = 639 points, for about 3 AA kills. (213 points per kill). That’s translates to 10 AA kills for Oahu.

Summary – I’m guessing a reasonable AA scenario of the fighters/dive bombers vs. Oahu with Kimmel’s fleet mostly absent (therefore the 1st wave Kates also absent) is about the historical 9-10 planes lost per wave, for 20 in total. If for some reason the 1st wave torpedo bombers disobey their mission and come back to attack transports in the harbor, then add another 15 or 20 kills.

Throw in the fact that the American fighters would have outnumbered the Japanese fighters around 3-1 (99 P-40 & 39 P-36 or 135 vs. 45 Zeros in the 1st wave) allowing at least 30-40 fighters a straight shot at the attack aircraft and also, not incidentally, removing the flak suppression strafing called for in the Japanese plan of attack.

A number of assumptions are being made.

1. Kimmel is far at sea but no fighters from Oahu are protecting him
2. The USAAF has made an optimal intercept despite an experimental radar system and little training.
3. The fighter availability rate on the morning of the battle is 100% of OOB.

#2 and #3, ok, let’s assume these can happen if Short gets really lucky, but not #1. Kimmel will have a CAP. Let’s say 36 x P-40 are protecting the fleet, leaving 63 x P-40 and 39 P36’s over Oahu. P-40’s on a good day are good for maybe .33 kills each, and your P-36’s may add another 9 or so. In return, probably about 30 defending fighters will fall in air to air combat and say another 30 will be caught and destroyed on the ground by the second wave.

So that’s 30 IJN aircraft shot down by fighters, another 18 by anti-aircraft for a total of 48. Maybe about 60 defending fighters have been destroyed, divided equally between air and ground attack. The air bases are hammered, so defending air operations tempo is now interrupted.
 
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CalBear

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Well, a few things need to be mentioned. Firstly you missed the 8 radar directed 90mm batteries, which were probably the most lethal guns involved in the action, followed by the 3" mobile guns. THe ships in harbor were almost exclusively firing their 5'/25 under local control, this greatly reduced that already marginal performance of the 5" guns. The 1.1 was also a marginal system, one that was being replaced as rapidly as the ships could be cycled through for refit.

It seems likely that the capacity of the ground based AAA, if it was properly manned and with ammunition available is being greatly devalued. The potential damage to the airbases also seems vastly overvalued, the only forces dedicated to the airbases 54 Vals with GP bombs as well as strafing Zeros. Using the same comparative, Midway (which is, of course a far from ideal measure on either hand, however, any port in a storm...), a more potent IJN force did virtually no damage to the Island's air facilities. For that matter, after the through bastuning of both waves of the OTL attack, the airflied were in operation as soon as the skies cleared, and 41 fighters were undamaged and ready for action (25 P-40 and 16 P-36, not including the more or less worthless 14 P-26).

It is very unlikely that the P-40 or P-36 force would have any significant presence over the fleet. Army pursuit pilots were generally not used in long over water flights since their aircraft at the time had limited navigation capacity (long over water flights were usually done with the assistance of a multi-engined "mother ship" to provide course corrections). Any coverage would have almost certainly have been from the 10 USN and 11 USMC Wildcats, 8 Buffaloes, and 25 SBD bombers (USN tactical thought at the time called for the SBD, with it two cowl mounted .50 and rear gunner .30 dual mount, to be used in an auxiliary heavy fighter role against torpedo planes, it wasn't until Midway that this was changed), although there is also the not unreasonable chance that these assets would have been used against the incoming raid, which would have appeared on the thoroughly aroused, ITTL, air defense radars at roughly sunrise (which on December 7th was at 0659 local) or around 30 minutes after the practical launch time of aircraft in any number in the AM twilight period. That is why these aircraft were not included in the figures related to defending the base. The fleet would also have had the PBY force mainly deployed in a fan pattern ahead, both in an ASW and search role seeking out the Japanese fleet.

Thank you for your detailed feedback.

Taking the higher totals from your list and the PHA listings, I make the A-A defences to be something like this:
On ships...........5"........232
On ships.............3".........135
On ships.........40mm.........1
On ships............1.1"........64
On ships.........50 Cal......397
Base… …………….5.5"……….18
Base………………3"………….110
Base……………..20mm………56
Base………..……37/40mm………63
'Base………..……50 Cal………214

Using this somewhat arbitrary AA point system
5” – 6 points
3” - 3 points
40/37mm – 9 points
20mm/1.1” – 3 points
50 Cal – 1 point.


That's roughly 3782 points of anti-aircraft on the OOB historically.


In your story the US Navy has gone to sea and Kimmel is not found. So the torpedo bombers and level bombers of the 1st wave will not attack Oahu, rather, they branch out and search for Kimmel at sea and then apparently not find him, (sorry if I'm wrong on that detail). They are therefore not engaged by anti-aircraft or defending fighters. Most of the American A-A guns (2395 points of 3782) are on the ships that have left Oahu and therefore are not present for the air raid. Say 80% of the ship-carried A-A leaves the harbor and 20% remains. That’s maybe 1,900 A-A points in your scenario vs. the 3782 points from the historical raid. Even allowing for quickly sunken ships and the sluggish army response, the practical A-A values should be no more than about half of the historical 2nd wave, which killed about 9 aircraft by AA.

At Midway Island for the 4 June 1942, raid – 6x5”, 24x3”, 8x40mm, 18x20mm, 90x50-cal = 639 points, for about 3 AA kills. (213 points per kill). That’s translates to 10 AA kills for Oahu.

Summary – I’m guessing a reasonable AA scenario of the fighters/dive bombers vs. Oahu with Kimmel’s fleet mostly absent (therefore the 1st wave Kates also absent) is about the historical 9-10 planes lost per wave, for 20 in total. If for some reason the 1st wave torpedo bombers disobey their mission and come back to attack transports in the harbor, then add another 15 or 20 kills.



A number of assumptions are being made.

1. Kimmel is far at sea but no fighters from Oahu are protecting him
2. The USAAF has made an optimal intercept despite an experimental radar system and little training.
3. The fighter availability rate on the morning of the battle is 100% of OOB.

#2 and #3, ok, let’s assume these can happen if Short gets really lucky, but not #1. Kimmel will have a CAP. Let’s say 36 x P-40 are protecting the fleet, leaving 63 x P-40 and 39 P36’s over Oahu. P-40’s on a good day are good for maybe .33 kills each, and your P-36’s may add another 9 or so. In return, probably about 30 defending fighters will fall in air to air combat and say another 30 will be caught and destroyed on the ground by the second wave.

So that’s 30 IJN aircraft shot down by fighters, another 18 by anti-aircraft for a total of 48. Maybe about 60 defending fighters have been destroyed, divided equally between air and ground attack. The air bases are hammered, so defending air operations tempo is now interrupted.
 
This is kinda ironic - CalBear, if I understand you rightly, having shore defences at heightened alertness and US fighters in the air over Pearl actually increases total US casualties? I'm confused. I would think the men would be better off fighting rather than being strafed on the ground, if you will pardon my over-simplistic line of argument.
 

CalBear

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This is kinda ironic - CalBear, if I understand you rightly, having shore defences at heightened alertness and US fighters in the air over Pearl actually increases total US casualties? I'm confused. I would think the men would be better off fighting rather than being strafed on the ground, if you will pardon my over-simplistic line of argument.

Ships that sink in 5,000 feet of water tend to lose far more men than if they are in 22 feet. The Oklahoma lost 422 men out of a crew of ~1,700 IOTL, despite turning turtle, while the Arizona, which suffered a high order magazine detonation, lost roughly 3/4 of its crew (1177 out of 1512).

HMS Hood, having suffered a catastrophic magazine explosion virtually identical to the Arizona's had three survivors from a complement of 1,417.

There is also the not insignifcant matter of the support ships that were left in port and upon which the Japanese aircraft vented their frustration. USS Tangier had a complement of nearly 1,200, while the Curtis' was over 1,000 and the Pelias was over 900.

The ships left in port had large crews and little armor. When they were hit, especially those that were torpedoed, losses were substantial.
 

BlondieBC

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HMS Hood, having suffered a catastrophic magazine explosion virtually identical to the Arizona's had three survivors from a complement of 1,417.

If you go through list of dreadnoughts lost to main magazine explosions, 20 survivors is a huge number to live. And even if the magazine does not go boom, it can be risky picking up survivors with possibly multiple subs in the area. And fear of airstrikes. Nothing like stopping a ship to pickup survivors to make a submarine captain job easy. The would likely be well aware of the fate of the "live bait" squadron of WW1.
 

CalBear

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If you go through list of dreadnoughts lost to main magazine explosions, 20 survivors is a huge number to live. And even if the magazine does not go boom, it can be risky picking up survivors with possibly multiple subs in the area. And fear of airstrikes. Nothing like stopping a ship to pickup survivors to make a submarine captain job easy. The would likely be well aware of the fate of the "live bait" squadron of WW1.

Absolutely. The difference between having it happen at sea and having it happen where you have 100 years to get to dry land and some medical care (not to mention, at least in Hood's case, having water 35 degrees warmer to swim through for those 100 yards) is huge.

Actually, when you consider the catastrophic detonation that the Arizona experienced it is remarkable that 25% of the men aboard survived the concussion wave from the explosion.
 
Ships that sink in 5,000 feet of water tend to lose far more men than if they are in 22 feet. The Oklahoma lost 422 men out of a crew of ~1,700 IOTL, despite turning turtle, while the Arizona, which suffered a high order magazine detonation, lost roughly 3/4 of its crew (1177 out of 1512).

HMS Hood, having suffered a catastrophic magazine explosion virtually identical to the Arizona's had three survivors from a complement of 1,417.

There is also the not insignifcant matter of the support ships that were left in port and upon which the Japanese aircraft vented their frustration. USS Tangier had a complement of nearly 1,200, while the Curtis' was over 1,000 and the Pelias was over 900.

The ships left in port had large crews and little armor. When they were hit, especially those that were torpedoed, losses were substantial.

Thanks for the explanation. So basically I-23 tipped the scales by sinking the two BBs ITTL, I get it now.

So basically the instinct to sail out to meet the threat proved to be hurtful, interesting.

...where you have 100 years to get to dry land...

You might want to edit that Calbear! :)
 

CalBear

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Thanks for the explanation. So basically I-23 tipped the scales by sinking the two BBs ITTL, I get it now.

So basically the instinct to sail out to meet the threat proved to be hurtful, interesting.



You might want to edit that Calbear! :)

Some of us are not adept swimmers.


Or spellers.


:eek:
 
THe ships in harbor were almost exclusively firing their 5'/25 under local control, this greatly reduced that already marginal performance of the 5" guns. The 1.1 was also a marginal system, one that was being replaced as rapidly as the ships could be cycled through for refit.

Local control or no, it was still over 800 AA guns blazing away at IJN aircraft for the better part of an hour.

Most of the 18 (or so) IJN aircraft actually shot down by AA in the Pearl Harbor attack fell to the ship-mounted guns that are not present in your scenario. The ship-mounted portion of the island’s defenses amounted to around 829 guns while the land based ones were only about 461 guns. With most of these guns at sea, the defenders now have maybe about 600 guns instead of 1,300. You’re calling for an A-A lethality increase of around 600% while at the same time the total number of guns available is significantly reduced.
It seems likely that the capacity of the ground based AAA, if it was properly manned and with ammunition available is being greatly devalued.
To put it another way, two Iowa Class battleships from late 1944 had roughly the total anti-aircraft lethality of everything on Oahu not mounted to a ship, including all guns that were not manned in time.
The Midway defenses appear roughly 1/3rd the total land-based AA weight of your scenario. But Midway was also a far smaller island than Oahu – there might have been ten times the square mileage of targets to defend on Oahu, meaning that there should be a net reduction in anti-aircraft density on Oahu in comparison to Midway.
Well, a few things need to be mentioned. Firstly you missed the 8 radar directed 90mm batteries, which were probably the most lethal guns involved in the action, followed by the 3" mobile guns.
I thought all of these were included in the 110 “base” guns (60+26 army 3” and 24 Navy 3” / 90mm(listed with 3"). If the 90mm A-A guns are undervalued at ‘4’ points, simply increase their point value. Here,
http://www.matrixgames.com/forums/printable.asp?m=3042207
American forces on Luzon had 66 x37mm AA and 62 x3” AA guns. These are broadly similar OOB totals of these guns types compared to what was on Oahu, but the number of aircraft they shot down at Luzon was minimal – I’m not certain any IJN aircraft were lost to defending AA in the first days of the attack despite all this anti-aircraft firepower.
The potential damage to the airbases also seems vastly overvalued, the only forces dedicated to the airbases 54 Vals with GP bombs as well as strafing Zeros. Using the same comparative, Midway (which is, of course a far from ideal measure on either hand, however, any port in a storm...).
Despite the lack of doctrine and training at the time, an optimal intercept has been made (all 135 fighters successfully hitting the first wave). The second wave (54 B5N2, 36 A6M2) will therefore catch many of these fighters rearming and refueling on the ground after their first air combat, so if anything the number of aircraft destroyed on the ground by these 90 aircraft may be understated. The question of what Egusa does with his 81 bombers is also a factor. Your AA results suggests he hits naval ships still in harbor or the naval base, but his mission orders instead should call for him to search for the warships at sea (in which case he will suffer no AA losses). Many of his bombers, failing to find suitable targets, may choose to hit the airfields on their way through. Others might attack ships in the harbor, but given that AA defences there are now only a small fraction of the historical, their losses will be correspondingly minimal. Since the CAP shot its bolt against the 1st Wave, I doubt the 2nd wave suffers too many CAP losses.
 
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