5 Minutes warning - the ships are closed up at action stations all doors doubled dogged - a handful of US Aircraft might get airborne in time to do something.
Couldn't disseminate the news that fast. Frex, most likely some members of the Arizona's crew didn't even know a war was on when they died, especially those in the Black Gang.
1 hours notice - it would take no more than an hours notice for the Battleships to come up to steam to power all their weapons and be closed up at action stations.
Allow for the fact that most BBs only had one boiler lit that morning. The only reason the Nevada could make her famous run for the open sea was because the acting chief engineer had kept an extra boiler lit (against protocols) so he could do the switchover later that morning. Also, ALL the ships in harbor suffered from having too many crew members ashore.
I suspect that this would also be enough time for the Pilots to shake off hangovers and a decent number of fighters Fueled and armed - their engines warmed up
For those quartered near their planes...
But it won't make much difference, other than perhaps more pilots killed on the tarmac.
Four Hours - All capital ships (bar the one in Drydock) - enough steam to move and all aircraft bombed up and dispersed etc.
Actually, if Kimmel absolutely hits the panic button, and the rest of the BBs' captains, divisional commanders, and the Battle Force Commander himself (Pye) are willing to work as hard and fast as the Nevada's crew did, you could have the dilemma of a "crowding effect" of major warships trying to leave at nearly the same time. "Everyone storms the exits in the burning theater and no one gets out"?
The Nevada makes it out no question though. And the NV proved something under fire that had long been argued about in Pearl Harbor...A battleship CAN get underway, leave dockside, maneuver through the Inner Harbor, and presumably the Outer Harbor and Outer Channel WITHOUT the aid of tugboats.
Getting the bombers and PBYs dispersed that quickly might be a problem in terms of getting them airborne. But if it can be done, they can go to the other islands for cover. Getting the bombers "bombed up" will take too long at Four Hours (penetrating disbelief and rounding up essential personnel in a "peacetime environment" is very hard).
This is actually dangerous for the US Fleet as ships might be caught maneuvring slowly leaving port.
This will depend a lot on US Army/Navy cooperation
, as with Four Hours Warning
the Opana Point radar station will not only remain manned and operating, but even under possible heavy guard. So no "Instant tactical surprise" ITTL. Which leads me to...
A BB sunk in the channel their might even block the harbor
That's what Harbor Masters are for. To throw up the Red Flag the moment the Opana Point radar installation tells the navy of the approaching Japanese attack waves and roughly when they could be expected to show up. So they would have "X amount" of time before throwing down the bar. This happened when the Nevada was turning towards the Outer Channel. The Harbor Master Station had the flags up closing the harbor. The NV's skipper agreed with the Master's decision and beached his ship, but there were more than a few angry junior officers who thought that the order was wrong.
But as you say, it wasn't.
BBs lost at sea might result in them being unrecoverable and suffer high crew casualties.
True, on an individual basis. But its not like they were the crews of the Repulse and Prince of Wales, sailing off to their doom. Or even the Bismarck's, who at least had the prospect of rescue by the British, and could have had a lot more survivors if an offensively disarmed U-Boat hadn't foolishly closed in, forcing the heavy cruiser Dorestshire to abandon the German sailors to their fate. A handful were rescued by the U-Boat, but that was all.
At Hawaii the Standards would be operating in friendly controlled waters and skies, in calm seas, warm water, and few (if any?) sharks. I say friendly skies because the Nagumo Force will have little time to tarry and strafe helpless sailors bobbling in the water. Not that they wouldn't if they got the chance.
However with several hundred Aircraft ready to defend / strike back it might also be dangerous for the IJN Strike fleet
Meh. Short's "7th Air Force" on 12/7/41 was as deadly as a kitten to targets at sea. I'd barely give them credit to handle supporting tactical operations defeating a Japanese invasion force (ASB), but the mass obsolescence of so many of their aircraft (B-18s, P-35s, P-36s, Buffaloes), or unsuitability for naval air strikes of others [B-17s, A-20s[size=-4](bomb load)[/size]], renders the entire body of aircraft on Oahu useless for any missions except diversion, recon, or CAP. And the CAP mission mainly due to her complement of P-40s.
I know some may point to the aircraft shot down by some of these iron coffins (NOT the P-40s) at Pearl OTL. BUT: The Japanese had never done anything like this. In some ways, even their vaunted veterans were "newbies". And they too made newbie mistakes. Since mostly only squadron and flight leaders had radios, once the fighters broke formation to hunt targets (seeing no aircraft in the skies), their commanders lost the ability to recall their planes quickly enough to deal with immediate threats, like a few fighters being able to take off and engage the enemy. An enemy who had grown complacent, thinking that there were no enemy planes aloft at all.
So when the Nevada made her run, there was no way for the Japanese to "call in the clans" from the moment she pulled away from the dock. So too when the handful of American fighters that got off the ground engaged the enemy, some could enjoy an initial level of surprise, especially the famous two pilots from the auxiliary field at Haleiwa. But then, they were flying P-40s.
...and at this time the Americans know NOTHING about the Zero, much less how to combat it. When they try to engage a bunch of "near-sighted pilots flying tinker-toys"
12 Hours plus - all of the BBs and ships that can have left port and the entire Island is on Alert.
Yeah, even the beach defenses are manned at this point.
What happens next depends but it can go really badly for either side - ie the Battleships try to go for the Carriers and either get lucky or get sunk at sea
The Standards lack the speed to catch up to Nagumo and Nagumo lacks the fuel to hunt for them. If Nagumo tries for a Third Wave, some of his DDs aren't getting home. If he stays through 12/8, NONE of them are. And since he doesn't know that the vaunted Mark XIV is fractionally less dangerous than a barrage of spitballs...
, he could in his own mind be facing a "Night of the Long Knives" before he ever gets home. IF he gets home. If there was one thing the world's navies had learned to appreciate, it was the power of the Submarine.
Probably what would happen is the US ships devoid of carrier support would move south east of the Island (under Air cover) - perhaps even return to the US West Coast out of range of any Japanese adventurism.
I doubt seriously that Kimmel would go that far. If he does, its only because he lacks the fuel and escorts to cover the Standards.
And yes, CAP is the One Thing I could trust Short's boys to pull off.
Meanwhile in Peal Harbor a phone in a 'Japanese barbers' rings unanswered.....
IDK about that. AIUI, the barber didn't even know who he was talking to. Its not a matter of making sure there is no one to answer the phone as it is to insure the person on the other end of the line is not able to make the call in the first place.
To shut down the Japanese intelligence operations to affect Japan's knowledge of the fleet sortieing, you'd need to storm or otherwise shut down the Japanese Consular Office from the outside world almost immediately. Then there's the issue of the Japanese submarines in the area, especially the midgets, who were giving vital intel to the IJN right up until 0400 on 12/7.
