Thanks for all the ignorance fighting! And did you know FDR knew about it ahead of time? J/K!!
eta: I wonder how that conspiracy theory got propagated in the olden days? Q’s grandpa?
The US had broken the Japanese diplomatic code, but from being able to have foreknowledge of the break off in relations at a certain time to know that an attack was coming to Pearl Harbor was a stretch.
John Toland wrote a book entitled Infamy arguing that FDR and the US had pre-knowledge of the attack and covered it up.
Ahem. Shouldn’t that be capitalized? 
The 14 part message delivered to Secretary of State Hull that was decoded by US cryptologists faster than it was by the Japanese diplomatic staff didn’t break off diplomatic relations any more than it was a declaration of war. All it did, as TokyoBayer noted, was end ongoing negotiations. It concluded with:
The Japanese Government regrets to have to notify hereby the American Government that in view of the attitude of the American Government it cannot but consider that it is impossible to reach an agreement through further negotiations.
You are correct.
A final instruction read, “Will the ambassador please submit to the United States Government (if possible the Secretary of State) our reply to the United States at 1:00 pm on the 7th, your time.”
The Japanese Language expert, Lt. Commander Kramer, who headed the translation section of OP-20-gz, was struck by the rupture at a certain deadline. He was alarmed by the unusual time–1 pm on a Sunday-- noting that it was 7:30 am in Pearl Harbor and in the early hours in the Philippines and Malaya.
A War Warning had been issued in late November, so Kramer started delivering this message, running through the streets to the State Department.
A no point, though, did the Japanese state what they were going to do, and the response to this warning was bungled.
Since this is the general Pearl Harbor thread.
So let’s pretend the USS Ward attack on the Midget submarine is somehow taken seriously. Pearl Harbor goes on full alert, aircraft scrambled, AA guns manned, so when the Japanese finally arrive the Americans are ready. The Zeros are able to wrest air superiority from the less experienced American aircraft but both waves do minimal damage due to intense AA fire. Almost all battleships escape harm.
So what do the battleships do now? War Plan Orange is no longer in effect, so how are they used tactically? I remember reading somewhere that the US Navy at one point planned to use the slow battleships in two ship commerce raids similar to how the Germans tried to use their battleships, so I wonder if this could have worked (with proper escorts of course)
Even if Pearl Harbor was on full alert the Japanese strike was going to inflict significant damage on the US battleships, possibly even permanently sinking more of them than they did historically. There was an hour and twenty minutes between the Ward going to investigate the midget submarine contact and the beginning of the attack, which might have given the battleships enough time to work up steam, make it out of the harbor and be sunk in deeper waters where they couldn’t be refloated and returned to service.
The amount of AA fire that the US battleships and the US fleet in general could put up on Dec 7th, 1941 wasn’t very impressive; it was the early experiences in the war that led to the drastic increase in the number and capabilities of AA guns fitted on ships. For example, the entire AA armament of the battleship Pennsylvania at the time of the attack on Pearl harbor was the rather tepid total 12 5"/25 cal AA guns and 8 .50 cal machine guns. By contrast after her refit by late 1942 she sported 16 5"/38 cal Dual Purpose guns, 40 40mm Bofors AA guns and 51 20mm Oerlikon AA guns which also had much more effective fire control than her pre-war armament. The planes and pilots of the Kido Butai were able to consistently push home attacks through much more formidable AA fire than was available at Pearl Harbor during battles throughout 1942 and inflict significant damage on their targets. Consider the ease as well with which the Prince of Wales and Repulse were sunk three days later on Dec 10th by land-based torpedo bombers.
[Moderating]
I don’t think this was intentional, which is why this isn’t a Warning: The term “Japs” was widely used during WWII, and it’s an obvious shortening of “Japanese”. Regardless, it’s now considered a racial slur, and thus prohibited on the SDMB. Don’t do this again, or it will be a Warning.
The Army was responsible for the defense of Pearl Harbor. On full alert they would have manned their trenches.
This is an interesting question, but I don’t know how likely it would be that the outcome would be worse then the two battleships which were completely lost.
Prince of Wales’ anti-aircraft fire control radars were unserviceable and there was problems with the ammunition for the 8-barrel 2-pounder pom-poms, which caused the guns to jam. The first torpedo hit caused extensive damage, including an immediate 11 degree list, enough so that the 5.25-in AA guns on the high side could not depress sufficiently to engage torpedo bombers. Loss of electrical power prevented all eight of 5.25-in gun turrets from being trained. The aft pom-poms were frozen because of power loss and could not be trained manually.
Repulse only had eight 4-inch Aa and two pom-pom mounts.
Despite this dismal AA performance, the Japanese only managed six to eight torpedo hits out of 49 drops, between 12 to 16%. The war average was about 15%.
With only 40 torpedo bombers at Pearl Harbor, 0.15% success rate would be six hits. Battleships were expected to sustain at last four aerial torpedo hits without sinking so if all six were against one BB (which would be unlikely) that would have been the loss of one battleship. More likely, the six would be spread out among several ships and it’s possible no ships would be sunk.
The lever bombers would not have scored enough hits to sink anything.
The US ships, even with weak AA as compared to later in the war, would have the advantage of numbers. There would be seven battleships for the 40 torpedo bombers to chose from with six light cruisers and 20 ish DD also providing AA support.
The Japanese had not made plans if the fleet were at sea of Pearl, so the attacks would need to be improvised, not their strong point.
Many counter factuals assume that the AAF would be prepared as well. While that’s interesting to look at, with the one given by @Asuka, while the Navy would go on full alert, I doubt that news would be sent over to the Army or AAF in a timely fashion.
… And scrambled the fighters. Which may have helped to break up the first attack. You never know.
Of course, maybe they still wouldn’t have had time. Ward attacked the submarine at 0637; the first wave attacked an hour later. How ready were the fighters? How many could have gotten aloft that quickly?
Good point, however the army probably would have assumed they were repelling a land invasion, not an attack by air.
Why would they assume that?
Because they were an Army that was only 22 years separated from WW1.
Except they were also the Army Air Corps, not yet broken out into a separate Air Force, and had two years of recent history to observe modern war unfolding in Europe, and even WWI saw combined arms approaches to land warfare, with aircraft being used to support ground operations (armor, infantry, and artillery) as the war progressed.
Whether or not they would have made a connection from “midget submarine” to “Air Raid!” is of course speculative. It’s possible their response would have been limited to heightened patrols and I doubt they’d have put every single fighter they had into the air in any event, but even the Army of 1918 would have made a connection between ground operations and air support (and the need to counter it).
As you know, Billy Mitchell had warned of an air attack on Hawaii in 1936. But in 1941, citing Billy Mitchell was about as smart a career move for a US Army officer as citing Marshal Tukhachevsky was for a Soviet Army officer.
True enough, hence why I said possibly - simply that any battleship that sank in the open water wasn’t going to get refloated and returned to service by 1943 or so. I’d note two things with regards to Prince of Wales and Repulse though. One is that despite the early loss of AA power on the Prince of Wales, the AA armament of the British ships was quite heavy compared to that of the US battleships at the time. The 5.25" QF guns on the Prince of Wales were in theory rather more effective as AA weapons than the 5"/25 cal AA guns used by US battlewagons. The 8 barreled 2pdr (40mm) pom-poms on the British ships, in spite of all their faults, were still by far more effective automatic AA weapons than the single digit numbers of single mounted M2 Browning .50 caliber machine guns using Mk1 eyeball fire control that passed as the light AA armament on US battleships.
The second is that the Prince of Wales and Repulse were considerably faster ships at 28 and 31.5 knots respectively than the old US battleships, which could only make 21 knots, which would make them considerably easier targets for torpedoes while maneuvering than the British ships were.
The Army at Pearl had prepared for two things: espionage and a land invasion. After the raid they were still looking for both. They Reinforced their trenches and spread barbed wire along the beaches. They had active patrols looking for insurgents. The only battle occurred when two of the patrols encountered each other.
The Japanese did not employ either one. All of the observations of facilities were made from areas with public access, by individuals in plain view.
The Navy had twice conducted simulations, using the Lexington, to demonstrate that Pearl Harbor was vulnerable to carrier based air attack.
I think the problem was no one really believed it would happen. Early in 1941, Ambassador to Japan Joseph Grew had cabled his superiors rumors passed on by the Peruvian Minister to Japan: “Japan military forces planned a surprise mass attack at Pearl Harbor in case of ‘trouble’ with the United States.”
Grew’s report was provided to Admiral Stark and Admiral KImmel, but it was discounted by everyone involved in Washington, D.C., and Hawaii.
Clearly, they go on the offensive, and using their superior speed, catch up to the Carriers of the Combined Fleet, and blast 'em with their big guns. Oh wait, er…never mind.