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).
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.