What does Japan do if War against USA/UK/DEI postponed to Spring 1942?

Greg Boeser said:

No USN carriers early means no harrassment raids in Central Pacific. No Lea Salamaua raid. This means Japanese move earlier to sieze Port Moresby. Can be bolder about expanding island perimeter in South Pacific. Historically, the USN had just enough planes to equip just enough flight decks as CVs were lost.

Click to expand...

And to follow onto this, less buildup of experience in the American air-groups, which may influence the turn of later battles.

nuuumannn said:

You might be surprised how many of those countries offered. New Zealand offered to send a frigate, but the British declined and requested the RNZN carry out RN tasks in its absence in international waters.

Click to expand...

Cool!

If the carriers were in Pearl Harbor that morning, there's no doubt that they would have been attacked, but two things I might point out.

First, is how quickly most of the battleships were repaired to service.

Second, remember how thoroughly the Yorktown was damaged when she limped into Pearl? How long did it take to get her squared away and put back into the fight at Midway?

The strike at Pearl really didn't create a setback for the USN, as two battleships were virtually untouched and with the exception of the Arizona, Oklahoma and Utah (which was all but decimmissioned anyway), all the damaged battleships were put back into service and came back to haunt the IJN.

Very little infrastructure was damaged, like drydocks and fuel stores, so the carriers could have been refloated (if sunk), repaired, refueled and back in action in a marginal amount of time.

Sinking the carriers at sea, like what happened to the Hornet, Lexington, Yorktown, etc. did more to set back the USN than catching them at Pearl.

GrauGeist said:

If the carriers were in Pearl Harbor that morning, there's no doubt that they would have been attacked, but two things I might point out.

First, is how quickly most of the battleships were repaired to service.

Click to expand...

I'm skeptical the carriers would've held up better. 1) they're going to be at least as vulnerable to torpedoes, and present 150-200 foot more length to target, and 2) the second wave attack, weighted towards dive-bombers, would probably be much more effective against wooden decks than Nevada's armor, so that even if the carriers survived the first wave they'd still be in trouble against 550-lb bombs.

Repairing the carriers would probably be easier than repairing the BBs, sure, but you're still going to be hogging up drydocks and recovery crews, and you won't have many decks doing things like the Doolittle Raid or fighting Coral Sea. You won't have air groups garnering experience so that when push comes to shove they actually know what they're doing under pressure.

GrauGeist said:

Second, remember how thoroughly the Yorktown was damaged when she limped into Pearl? How long did it take to get her squared away and put back into the fight at Midway?

Click to expand...

Three days, on an emergency basis, with work crews still aboard her when she went into her final battle. But she was mobile when damaged at Coral Sea, and was obviously more defensible for that fact, with CAP overhead, too, than she would've been on 7 Dec. Comparing Coral Sea to a surprise attack in harbor is an apples-and-oranges thing. Catching a carrier in harbor would mean less fuel and weapons out of storage, but would also mean that the big 800' ship isn't dodging much being dropped by 350 aircraft.

GrauGeist said:

The strike at Pearl really didn't create a setback for the USN, as two battleships were virtually untouched and with the exception of the Arizona, Oklahoma and Utah (which was all but decimmissioned anyway), all the damaged battleships were put back into service and came back to haunt the IJN.

Click to expand...

I agree with most historians that, with the carriers untouched, it may have been a blessing in disguise which forced USN to refocus on carriers.

The real setback at PH is, to my mind, the base got cluttered by wreckage and the drydocks had to be managed finely to provide for both recovery from the attack as well as repairs and refits on ships still on active-duty.

I can't really think of any battle the standard battleships could have changed in 1942, which is probably why the active survivors were sent to the West Coast and even left home at Midway and Guadalcanal.

GrauGeist said:

Very little infrastructure was damaged, like drydocks and fuel stores, so the carriers could have been refloated (if sunk), repaired, refueled and back in action in a marginal amount of time.

Sinking the carriers at sea, like what happened to the Hornet, Lexington, Yorktown, etc. did more to set back the USN than catching them at Pearl.

Click to expand...

I think that depends on how the carriers were sunk or damaged. If it capsizes, you've still got a big problem. If it's burned out by vertical/dive bombing, probably easier; it's not combat-loaded in port and you won't get Midway-style fireworks. But in either case even those carriers are going to be sidelined a lot longer than Yorktown's three days in May, I suspect. The resources and experience just aren't there yet in Dec 1941.

While you're right that it's an easier job than refloating/repairing a BB, you're still losing fast assets very early in the war, and probably over a much longer time than Yorktown's hurried repairs after Coral Sea, given that the yard crews wouldn't already have that repair experience nor resources/materials at hand.

All told, I think it would have been a much bigger problem had the Big E and Lady Lex been in harbor that day.

And that could as well redound upon the aircrew experience on those carriers, not being able to mount raids in order to garner said experience in early 1942.

The reason Utah was hit so hard is her berth is where a carrier would have been. So that's not good for Utah although the IJN did waste good torps on a minor target and did hit USS Raleigh maybe by accident.

Wasp was vulnerable so wasn't used in the Pacific because she could go up in flames and so the errrrrr...... nevermind.

The Standard were 21 kts anchor with very little in the way of combat effectiveness. So if they did try and chase IJN carriers at Pearl then good luck with that. Plus any battleship sunk at sea is lost so that's worse.

So only Lexington and Enterprise were targets but they were at sea. Ranger, Wasp, Yorktown and Hornet were in the Atlantic. Saratoga was in San Diego.

Although the Submarine force at Pearl wasnt a target either.

Pearl Harbour had to be occupied or totally destroyed. Neither happen so kinda made it a strategic dead end.

While all the Battleships at PH, except Arizona and Oklahoma, were returned to service eventually, the scale of the repairs required to some of them should not be underestimated. Colorado missed PH by being in refit on the West Coast, something which didn't complete until March 1942. Only Pennsylvania, Maryland and Tennessee completed repairs in Feb 1942 and even they had to be sent back to the West Coast. Pennsylvania had been in dry dock while the other pair had been protected by having other ships tied up outboard of them.

Nevada wasn't refloated until mid-Feb 1942 was under repair first at PH and then the West Coast until the end of the year.

These survivors later spent substantial periods of time in dock being refitted / reconstructed much further. Tennessee for example was reconstructed between Aug 1942 and May 1943.

The two worst affected ships were West Virginia and California, being outboard ships in Battleship Row. West Virginia took 6 torpedoes, wasn't refloated until May 1942, and didn't return to active service until July 1944 having been totally reconstructed. California wasn't raised until the end of March 1942, wasn't fit to sail to the West Coast until Oct, and her repairs and reconstruction lasted until the end of Jan 1944.

In the final Japanese plan, 16 of the first wave of B5N Kate torpedo bombers were ordered to target the moorings where the carriers would have been tied up and which was where Utah was located. The expectation was that they would achieve 8 hits on the two carriers they expected to be present. Those torpedo hits would have been along one side of each vessel so risking the danger of capsise, like Oklahoma. That would have complicated the salvage work. The remaining 24 were to target the Battleships.

The priority for the 81 Val dive bombers in the second wave was to be the carriers, even if they were already sinking, in order to make them unsalvageable. Then they were to target cruisers. Weapons were 250kg bombs. They were expecting up to 44 hits (war experience showed this could be as low as 20% rather than the 55% expected). So even if a fraction were to target the carriers there would have been multiple hits. Look to their performance against moving targets like Cornwall, Dorsetshire and Hermes 5 months later for the hit rate that they could achieve on a good day.

So had the Lexington and Enterprise been present at PH on 7th Dec there has to have been a good chance that they would not have been back in service until well into 1943 if at all.

Edit:- incidentally the difficult salvage work on the capsized Oklahoma didn't start until March 1943. She wasn't righted and refloated until Nov, and it was Dec before she had enough water pumped out to put her in dry dock. There are photos here of the salvage work. Note the huge frames that had to be attached and the winches installed on Ford Is to right her. It was a huge effort.

Could not the Japanese launched a float plane at first light to see what's at Pearl before the first wave?

Could have painted it in USN colours.

The Japanese did attack some odd targets and could have done well with a Forward Air Controller.

The Basket said:

Could not the Japanese launched a float plane at first light to see what's at Pearl before the first wave?

Could have painted it in USN colours.

The Japanese did attack some odd targets and could have done well with a Forward Air Controller.

Click to expand...

The more recon stuff you have in the air (or using periscopes from mini subs) the greater the chance you have for surprise to be lost.

Just as a follow up to my last post, here is the map of the first wave attack by the Japanese torpedo bombers.

The Detroit, Raleigh, Utah and Tangier occupied the Carrier berths. 8 B5N torpedo bombers from each of Soryu & Hiryu were detailed to attack from over Pearl City. The flight leaders recognised that the carriers were not present and went looking for other targets. But 6 aircraft from the Soryu group did attack, putting two torpedoes into Utah and one into Raleigh.

So, for those that attacked, they achieved the 50% hit rate they expected, just not on the intended ships. Utah capsized as a result. Attempts were made to salvage her in 1944 using the same techniques as used for the Oklahoma, but they failed. She still lies where she sank in 1941. Photos here:-

This was Raleigh after the attack with salvage efforts underway. She was hit aft around the prop shafts rather than amidships in her engineering compartments. The capsized Utah can be seen astern of her.

The Basket said:

Could not the Japanese launched a float plane at first light to see what's at Pearl before the first wave?

Could have painted it in USN colours.

The Japanese did attack some odd targets and could have done well with a Forward Air Controller.

Click to expand...

The Japanese did launch a floatplane from each of the cruisers Chikuma and Tone in pre-dawn darkness. Tone's aircraft was sent to check out the anchorage at Lahaina Roads sometimes used by the US Pacific Fleet. Chikuma's was sent to PH. It reported before the second wave was launched. It is not known if that signal was relayed to Fuchida as strike leader of the first wave.

An FAC would have done no good. Radio silence was maintained, even after the attack began. Most Japanese fighters were not radio equipped and the voice radios that were fitted to other aircraft were not considered reliable by crews of aircraft that had them, so hand signals remained the order of the day until the various flights broke up.

The odd thing is that intelligence reports from Japan's PH legation which were passed to the strike force and gave a picture up to 6 Dec Tokyo time (5 Dec Hawaii?) disclosed no carriers were present, yet the plan wasn't changed. When the group leader then found them missing he led 10 aircraft looking for other targets and then they had problems with ship ID, a common problem for aviators of all sides in WW2. As a result they attacked some less than worthy targets.

Then there was confusion when the first strike reached Oahu over which attack plan was to be used (that was to depend on whether or not surprise had been achieved). That depended on Fuchida firing either 1 or 2 flares. But despite surprise being achieved 2 flares were fired because he thought part of the group hadn't seen the first flare! That meant the attack was not as organised in its execution as intended.

The TB approach to battleship row also seems to have had the effect of funnelling them to the centre of the line, which explains West Virginia getting hit 6 times, but Nevada only once.

Before the dive bombers of the second group took off they were informed that there were no carriers and were told to attack / finish off ships hit by the first wave. That contradicted the prioritisation in the plan and meant they were expending GP bombs against Battleships instead of cruisers.

So the attack wrought a lot of damage on the US Pacific Fleet, but its execution was less than perfect for a variety of reasons. The Japanese made a number of mistakes, and in the process did not do as much damage as they could have, even if they did not hit the facilities.

Attack on Pearl Harbor - Strategy, Combat, Myths, Deceptions by Alan D Zimm is worth reading.

Amazon product ASIN 161200010X
View: https://www.amazon.co.uk/dp/16120001/

The map shows a channel which points directly at West Virginia and Oklahoma which the Kates could fly down. This was called the South East Lock.

To attack the other battleships the Kates would have to fly over land and buildings which would mess up the torp launch.

This is why Oklahoma was hit by maybe 10 torps.

IJN Floatplanes could use coloured flares to indicate targets of interest.

USS Shaw is a good example of poor target selection.

From everything I've read, Japan's internal politics was largely driven by a very aggressive military clique, who would assassinate anyone who counseled moderation. What would Japan do? Continue its murderous invasion of China, have its aggressive military clique members get increasingly aggravated that the US/UK/ etc isn't rolling over, who would probably lash out at somebody. Who's nearby?

It pains me deeply to see no one has mentioned the Japanese occupation of Vladivostok.

The withdrawal from Russian territory was another stab in the back for the Japanese army.

The Japanese took a page from the western way of Imperialism.

Gotta invade something.

It warms my English heart.

Shortround6 said:

The more recon stuff you have in the air (or using periscopes from mini subs) the greater the chance you have for surprise to be lost.

Click to expand...

True, but the more recon you have in the air, the better informed of the state of play you are. Accurate intel can mean the difference between success and failure.

It's also worth mentioning that in this scenario at Pearl that Japanese recon aircraft are likely to not arouse as much suspicion as they would have following the raid. In the first few days of December 1941 the USA and Japan were not at war and also it's unlikely that your average US serviceman would be able to determine the intent of a lone aircraft flying high over the island that defied identification. Very little was known about Japanese types within the US armed forces, so a single aircraft flying about might have raised eyebrows, but to what extent would the US reaction to it be?

swampyankee said:

What would Japan do? Continue its murderous invasion of China, have its aggressive military clique members get increasingly aggravated that the US/UK/ etc isn't rolling over, who would probably lash out at somebody.

Click to expand...

Japan needs to receive a thrashing in China. That's what kept them out of Russia.

Britain, USA, France and Holland need to advance and ramp up their support of the Chinese Nationalists. Only the US and perhaps the oil-rich Dutch have the money, but they all have the means if given the willpower.

The Basket said:

The Japanese took a page from the western way of Imperialism.

Gotta invade something.

It warms my English heart.

Click to expand...

There's always Macao and Timor. What's Portugal gonna do about it?

nuuumannn said:

True, but the more recon you have in the air, the better informed of the state of play you are. Accurate intel can mean the difference between success and failure.

It's also worth mentioning that in this scenario at Pearl that Japanese recon aircraft are likely to not arouse as much suspicion as they would have following the raid. In the first few days of December 1941 the USA and Japan were not at war and also it's unlikely that your average US serviceman would be able to determine the intent of a lone aircraft flying high over the island that defied identification. Very little was known about Japanese types within the US armed forces, so a single aircraft flying about might have raised eyebrows, but to what extent would the US reaction to it be?

Click to expand...

I'd imagine a bunch of floatplanes flying around on an early Sunday morning would arouse some attention.

When the B-17s flew into the Japanese flights, they thought there was war games going on and had no idea the Japanese were hostile.

Well, at least until they got attacked.

GrauGeist said:

When the B-17s flew into the Japanese flights, they thought there was war games going on and had no idea the Japanese were hostile.

Well, at least until they got attacked.

Click to expand...

The incoming B-17s also caused Lt Tyler to shrug off the Opana Point radar detection of the Japanese first wave. He told Elliot and the other guy whose name I forget that they were the expected incoming Forts.