WI: US gets 90 minutes warning of PH?

[RousseauX]

Pearl Harbor attack was somewhat truely astounding in the amount of surprise it achieved considering the sheer size of the force moving across the Pacific. The US was caught completely flatfooted as the Japanese attacked achieving total surprise.

What if the US gets just a little bit more advance notice? Let's say someone spots Kido Butai 1.5 hours before the first bombs are dropped otl and radios in a warning and it is believed. 1.5 hours is enough to get anti-aircraft men to their battle station and some planes in the air, but IJN still has relative surprise. How does the attack work out?

 

[marathag]

OTL Clock starting ticking at 6:45am til the first bomb dropped at 7:48am That's an hour right there.


The USS ANTARES, with a 500‑ton steel barge in tow, arrived of Pearl Harbor from Canton and Palmyra at about 0605, when it exchanged calls with the WARD. At 0630 the ANTARES sighted a suspicious object, which appeared do be a small submarine, about 1500 yards on its starboard quarter. The ANTARES notified the WARD and asked it to investigate, and several minutes later, at about 0633, observed a Navy patrol plane circle and drop two smoke pots near the object (Exhibit 73).

The WARD complied and at 0610 sighted an unidentified submarine one point off its starboard bow, apparently following the ANTARES into Pearl Harbor. General quarters were sounded and all engines ordered full ahead, increasing the WARD's speed from five to twenty‑five knots. At 0645 she opened fire with guns 1 and 3, firing one shot from each gun. The attack lasted only one or two minutes. The first shot, at a range of approximately 100 yards, passed directly over the conning tower; the second, from No 3 gun, at fifty yards or less, hit the submarine at the waterline junction of the hull and conning tower. At about this time, the ANTARES, observing the fire of the WARD, also noted that the Navy patrol plane appeared to drop bombs or depth charges at the submarine. The submarine keeled over to starboard and started to sink. The WARD ceased firing and then dropped depth charges A large amount of oil appeared on the surface. The submarine went down in 1,200 feet of water (Exhibit 74).

At 0651 the WARD sent a radio message to the Commandant, FOURTEENTH Naval District (Exhibit 18):


"We have dropped depth charges upon subs operating in defensive sea area."


The captain of the WARD, after reflecting that this message might not be interpreted as showing a surface submarine contact, at 0653 sent the following supplementary message:


"We have attacked fired upon and dropped depth charges upon submarine operating in defensive sea area (Exhibit 18)."

This message was received by the Bishop's Point Radio Station, relayed to the Officer in Charge, Net and Boom Defenses, Inshore Patrol, and delivered by the Communications Watch Officer, FOURTEENTH Naval District, to the ComFOURTEEN Duty Officer. The Duty Officer notified the ComFOURTEEN Chief of Staff at 0712 and, at the latter's direction, the Duty Officer of the Commander in Chief, Pacific Fleet, at 0715.

 

[Major Major]

The ships go to General Quarters. Boilers are lit off to provide power, men go to their stations and wait to provide anti-aircraft fire.

The airplanes are prepared and some are in flight.

Halsey is warned, and he stands off, prepared (being Bill!) to launch a counterstrike.

Macarthur is informed. Wishing to preserve the neutrality of the Philippines, he does nothing.

 

[rob2001]

In the book Rising Sun Victorious, their was a story written about what would happen if, Kimmel and Short were warned before the attack. It didn't end well for the Pacific fleet.

 

[JamesHunter]

The ships go to General Quarters. Boilers are lit off to provide power, men go to their stations and wait to provide anti-aircraft fire.

The airplanes are prepared and some are in flight.

Halsey is warned, and he stands off, prepared (being Bill!) to launch a counterstrike.

Macarthur is informed. Wishing to preserve the neutrality of the Philippines, he does nothing.

Its still a peacetime sunday and 90 mins might not be enough time to unfrak the mess at Pearl. Notably its unlikely the stupid masses of planes in the middle of the fields can be towed apart and flown off that quickly.

That said if all bulkheads are sealed and ships manned (if likely not fully ready that early on a sunday) it will keep more of them afloat and perhaps reduce the cataclysmic OTL damage so repairs can be done quicker.

Sadly though there isn't a hope of sortieing the fleet that fast so they'll still be stuck in a confined space at a time when American AA is still fairly weak and has no on the job experience.

Still a bad day but a slightly mitigated one if luck is on their side.

 

[TimPhillips]

The 2nd strike against Pearl took heavier losess due to the guncrews being ready. In a warned situation....the AA guns are crewed and ready and a stiff defense is immediately offered. To say nothing of the disruption a mass of defensive fighters over Pearl could have caused. The Japanese strikes still roll in...they still do a lot of damage...but they are going to have a tougher time and take heavier losses. I don't see anything really big that changes.

 

[McPherson]

Pearl Harbor attack was somewhat truly astounding in the amount of surprise it achieved considering the sheer size of the force moving across the Pacific. The US was caught completely flatfooted as the Japanese attacked achieving total surprise.

What if the US gets just a little bit more advance notice? Let's say someone spots Kido Butai 1.5 hours before the first bombs are dropped otl and radios in a warning and it is believed. 1.5 hours is enough to get anti-aircraft men to their battle station and some planes in the air, but IJN still has relative surprise. How does the attack work out?

Note previous comments. Now some technical comments.

1. It takes 12 hours to go from cold burners to full power on a steam turbine set. Nothing has changed this requirement. Hence modern warships use combination propulsion or gas turbines.
2. It takes a WWII ground crew one hour, to fuel, and arm a fighter for a sortie.
3. US warships at their moorings have to take on dockside hydraulic and electrical power when their propulsion plants are cold. Without their umbilicals they are helpless.
4. Usually for WWII era USN ships. the manning during the last months of peace was 3/4 of required complement because so many PACFLT veterans were being siphoned off to form core cadres for new LANTFLT ships.
5. Communications ship to shore passed through five layers of command before the guy on the Ward reached CINCUS. One of those command elements was this guy. I have an opinion about his culpability for 7 December 1941. In function the communications chain from USS Ward's warning to action was incredibly slow.

With that all in mind, 90 minutes warning would have made no difference at all. They had warning by submarine contact and by radar. The alert five fighters were left unmanned, the ships' ready use ammunition was left lockered. Nobody even bothered to run ship's boats or harbor patrol craft out as an improvised torpedo barrier to protect battleship row.

In other words... Nobody acted with what real time warning they had or passed the alerts they received along for action.

There was a lot of blame for Pearl Harbor, but essentially the two men responsible for the opey dopery (because the lax attitude in the organization always starts at the top and rolls downhill) were ADM Kimmel and GEN Short.

 

[gatordad699]

Note previous comments. Now some technical comments.

1. It takes 12 hours to go from cold burners to full power on a steam turbine set. Nothing has changed this requirement. Hence modern warships use combination propulsion or gas turbines.
2. It takes a WWII ground crew one hour, to fuel, and arm a fighter for a sortie.
3. US warships at their moorings have to take on dockside hydraulic and electrical power when their propulsion plants are cold. Without their umbilicals they are helpless.
4. Usually for WWII era USN ships. the manning during the last months of peace was 3/4 of required complement because so many PACFLT veterans were being siphoned off to form core cadres for new LANTFLT ships.
5. Communications ship to shore passed through five layers of command before the guy on the Ward reached CINCUS. One of those command elements was this guy. I have an opinion about his culpability for 7 December 1941. In function the communications chain from USS Ward's warning to action was incredibly slow.

With that all in mind, 90 minutes warning would have made no difference at all. They had warning by submarine contact and by radar. The alert five fighters were left unmanned, the ships' ready use ammunition was left lockered. Nobody even bothered to run ship's boats or harbor patrol craft out as an improvised torpedo barrier to protect battleship row.

In other words... Nobody acted with what real time warning they had or passed the alerts they received along for action.

There was a lot of blame for Pearl Harbor, but essentially the two men responsible for the opey dopery (because the lax attitude in the organization always starts at the top and rolls downhill) were ADM Kimmel and GEN Short.

Couple of nitpicky technical points.
1. It only takes a few hours to get a steam plant going. You can spin the main engines once astern and once ahead and go. The SSTGs can also be started and loaded in around 5 minutes if needed.
3. Ships only bring on shore power. The hydraulic plants are self contained and powered by electric pumps.
It takes several hours to bring on shore power. Can’t imagine having to hook up 4000 psi hydraulic lines.

 

[Major Major]

And I forgot the most important point.

All ships go to Condition ZEBRA, all watertight doors and hatches closed.

Thus damage from torpedo hits is contained. The California sank because she was at Condition X-RAY, everything opened up for inspection.

 

[Riain]

I read somewhere once that the code breakers learned that the Japanese had divided up PH or the island or whatever into grid squares and if someone (maybe Kimmel) had known that he would have changed the alert level or whatever and something about using a dispersal anchorage and airfields.

Has anyone ever heard anything like that?

 

[Carl Schwamberger]

I read somewhere once that the code breakers learned that the Japanese had divided up PH or the island or whatever into grid squares and if someone (maybe Kimmel) had known that he would have changed the alert level or whatever and something about using a dispersal anchorage and airfields.

Has anyone ever heard anything like that?

Yes. Without belaboring the details you have one of the more distorted versions.

The 'Grid Square' is one of those intel fragments that does not mean much by it self. A analyst needs a number of fragments to create a recognizable picture out of the puzzle.

 

[Animal Mother]

Granted it would take a lot more time than 90 minutes, but if the fleet sorties out of Pearl and into deep water, any ships that are sunk are not going to be recovered or salvaged. I expect losses could be even worse if the sortie is disorganized or piecemeal.

 

[Riain]

Yes. Without belaboring the details you have one of the more distorted versions.

The 'Grid Square' is one of those intel fragments that does not mean much by it self. A analyst needs a number of fragments to create a recognizable picture out of the puzzle.

Yeah, I read it years ago and didn't get right into it so there's no doubt it's distorted.

So if the grid reference was noticed as important what could be done in terms of dispersal and damage limitation while sticking to the peacetime operating regime? What dispersal anchorages and airfields are available, what ships and planes could be sent to them and how would that effect the results of the IJN strike?

 

[mattep74]

Considering that there were planes able to lift off and fight the second wave despite the carnage i think more planes would be in the air for the first wave

 

[Changundramon]

This may mean the Japanese DOW has been sent early, and thus the operation is not a sneak attack.

 

[JamesHunter]

This may mean the Japanese DOW has been sent early, and thus the operation is not a sneak attack.

Probably not, especially as it wasn't a DOW but "we're ending negotiations." As America expected war (just not a Pearl that day) its still a sneak attack before a formal declaration occurs, it just gets chopped up this time. Even then the issue was that the Japanese were being so secretive the Embassy couldn't use a professional typist and took to long to write it up, that won't change.

 

[Dorknought]

You would have to have a cast iron sighting report of the 6 carriers north of Hawaii in Kimmel's hand 90 minutes before the attack to make any difference. An air assault was ranked low probablity even though the USN had proven how vulnerable Hawaii was to surprise carrier strike 10 years previously.

They had days of warning (or as Al Murray says - the US was taken completely by surprise... two years into a global fucking war).

Message Sent by Navy Department, 27 November 1941:​

This dispatch is to be considered a war warning. Negotiations with Japan looking toward​

stabilization of the conditions in the Pacific have ceased and an aggressive move is​

expected with the next few days. The number and equipment of Japanese troops and the​

organization of the naval task forces indicates an amphibious expedition against either the​

Philippines, Thai, Kra Peninsula, or possibly Borneo. Execute an appropriate defensive​

deployment preparatory to carrying out the tasks assigned in War Plan 46 [The Navy’s​

war plan]. inform district and army authorities. A similar warning is being sent by the​

War Department.​

​

Department of Army dispatch, 27 November:​

Negotiations with Japan appear to have terminated to all practical purposes, with only​

the barest of possibilities that the Japanese Government might come back and offer to​

continue. Japanese future action unpredictable, but hostile action possible at any​

moment. If hostilities cannot, repeat, cannot be avoided, the United States desires that​

Japan commit the first overt act. This policy should not be construed as restricting you​

to a course of action that might jeopardize your defense. Prior to hostile Japanese action​

you are directed to undertake such reconnaissance and other measures as you deem​

necessary, but these measures should be carried out so as not, repeat, not to alarm civil​

population or disclose intent. Report measures taken. Should hostilities occur, you will​

carry out the tasks assigned to Rainbow Five [the Army’s war plan]so far as they pertain​

to Japan. Limit dissemination of this highly secret information to minimum essential​

officers.​

​

Message sent by Chief of Naval Operations, 3 December:​

Highly reliable information has been received that categoric and urgent instructions were​

sent yesterday to Japanese Consular posts at Hongkong, Singapore, Batavia, Manila,​

Washington and London to destroy most of their codes and ciphers at once and​

burn...confidential and secret documents.​

​

Note that War Plan 46 was 'aggressively raid into the Mandates.'​

 

[Major Major]

Probably not, especially as it wasn't a DOW but "we're ending negotiations." As America expected war (just not a Pearl that day) its still a sneak attack before a formal declaration occurs, it just gets chopped up this time. Even then the issue was that the Japanese were being so secretive the Embassy couldn't use a professional typist and took to long to write it up, that won't change.

Apparently, Hull had read the 14-point message before Kurusu and Nomura had! So I suppose he had prepared his striking reply.

 

[JamesHunter]

Apparently, Hull had read the 14-point message before Kurusu and Nomura had! So I suppose he had prepared his striking reply.

That and he could guess the contents even if he hadn't. Once it was clear it wasn't "we declare war," (even two hours late) blind fury was inevitable.

 

[Carl Schwamberger]

Yeah, I read it years ago and didn't get right into it so there's no doubt it's distorted.

So if the grid reference was noticed as important what could be done in terms of dispersal and damage limitation while sticking to the peacetime operating regime? What dispersal anchorages and airfields are available, what ships and planes could be sent to them and how would that effect the results of the IJN strike?

One of the least mentioned & studied aspects is what Short & Kimmel did on receiving the War Warning messages of 26-27 November. Most folks assume the military on Oahu continued some sort of sybaritic peace time existent. Well, a lot of individuals tried, but a description from one enlisted man seems to sum up the events from 27 Nov to 6th December. "The Brass went nuts" was his initial view. He went on to describe a frantic scramble to prepare for a Japanese attack of some sort. Sentries were posted every where, machine guns posted here and there, and relocated daily, anti aircraft weapons manned 24 hours a day, trenches dug, aircraft constantly flying off. The Fleet put to sea. This individual went on to describe how after a week the 24/7 alert fell apart from exhaustion.

Since I've found bits of similar evidence scattered thru the books. About how a maximum effort to stand up a defense fell apart. One PH historian I asked shared information on the air patrol/reconissance situation. Collectively the Army and Navy had enough patrol aircraft and bombers to maintain a tenous 360 air search. However that would have required terminating every other defense mission of the same aircraft. Local ASW patrols would have to be stopped, training stopped, and the formation of a air strike when the enemy was found would have required a excessive time as the bombers were collected back into a strike group. As it was maintaining a 75% search pattern was barely possible the first couple days. Some squadrons were under trained and the ground crew could not keep up with the demand of keeping the aircraft operational, parts were short, and aircraft were breaking down faster than repairs could be accomplished. Over the next six days the air reconnaissance effort collapsed. A similar denigration of capability occurred in many other sectors. The brand new radar sets lacked a parts kit for sustained all day operation, and lacked trained crews for all day operation. Exhaustion and inoperable radar sets accumulated.

The Battle Fleet sortied and took up station to the SE of Hawaii, as per Kimmels War Plan Pacific - 46. Over the horizon the fleet was not visible to any enemy reconnaissance or strike force over Oahu, but close enough to have air cover from Oahu. It was also a good position to ambush a enemy force approaching from the Marianas islands, the closest Japanese major Naval base. As with all other elements of the defense maintenance problems imeadately emerged. Some of the ships had been ready or undergoing critical repairs. Within a day those were starting to trickle back into PH lest they be crippled and have to be towed back. Many other maintenance issues emerged on the others, degrading their combat capability.

Abound the 4th or 5th December Short & Kimmel were forced to admit this could not go on. The decision was made to stand down, allow 24 hours of rest, and restart a more organized and realistic defense effort on the 8th December. Since the enemy attack predicted the previous week in November had not occurred the sense of urgency abated.

So getting back to the question, there was a lot that could be and was done. The problem is timing these preparations to match a attack you don't when it will happen. Had the Japanese shown up the 28th or 29th Nov they would have found the defense about as active as it could be. After that its in decline, the strength falling off. As it was the Japanese by accident hit the sweet spot of 7 Dec. Monday they'd found combat air patrols again, at least some air reconnaissance, and the ships fully crewed again.