Glenn239 said:
The tanks could have been badly knocked about, but to eliminate the yard facilities there would need to be uncontrolled fires. OTOH, space on Oahu was at a premium and no one was thinking about air raids, so it’s not at all unlikely that fire hazards were everywhere. The yard certainly would not have been prepared for an air attack.
Fact is, you don't need to actually do much damage to render the yard useless for heavies. Even simply knocking out the power station...
Glenn239 said:
The Pacific Fleet may have been using maybe 250,000 tons of oil each month for war operations. Since the tank farms are largely destroyed, most of this now has to come from California. The Pacific Fleet tankers therefore cannot even keep up with demand, leave alone replenish any eliminated stocks. The easiest way to square the circle is for the fleet to withdraw to California.
For the heavies, true. For the Sub Force, even a couple of tanker loads would be enough to keep them going; add a new facility at Midway, especially, & you're back at OTL capability, more/less. (Yes, the yard would still be useless, but major refits of subs were frequently done at Mare Is anyhow. OTL, I suspect that's because it was the yard was tied up with other work; TTL, the loss amounts to no difference.)
Glenn239 said:
All 20 aircraft lost in the 2nd wave were shot down at low level. So if a 3rd wave is made at low level over the harbor it might lose 20 aircraft, but if it is a high level attack over the harbor than losses might be negligible. Genda indicated there would be no more torpedo attacks, but I don't recollect him saying what he intended to do with his dive bombers).
The bigger question is, what are Nagumo's DDs doing all this time? Because they sure aren't swinging at anchor--& OTL, they were marginal for fuel to get back as it was.

Keep them on station long enough to carry off a 3d wave, you abandon them, either off Hawaii or en route.

IJN couldn't spare DDs. (Not that she was using them for anything really valuable, like protecting her trade...

No, she'd end up wasting them on
stupid supply missions in the Solomons, instead.


)