Japanese sink US carriers at Pearl Harbor, what next?

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CalBear

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There surely must be some misunderstanding, as you say Yoshikawa was giving the IJN and Nagumo everything they needed to know, as i understand it the day of the attack Nagumo knew there were no carriers in the port but there were 8 BBs, all this coming from Yoshikawa. The figures you mentions surely must refer to planning sometime in the autumn, i interpret that as meaning that the plan was in the eventuality that the totality of the Pacific Fleet was in port, they were to focus on four carriers and four BBs, hence the carriers had top priority. If the BBs had top priority, the orders would have specified forget the carriers and get all 8 or 9 or whatever BBs! And regardless, if any carriers were in port they would have been top priority target for the IJN pilots, no matter of what the top brass might have been saying.
Maybe. IJN lower ranks were not generally renowned for disobedience, but maybe.

The order outlining the target priorities and likely enemy forces were issued on November 23, three days (realistically two, since the fleet left port at 06:00 local) prior to departure.
 

CalBear

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I think the other questions are:
1) Are any of the carriers, BBs, or other ships sunk in such a way as to more fully block the channel?
2) Are the carriers sunk so as to be unrecoverable?
3) Does the fact that the carriers aren't then looming out there as a threat to the Japanese task force, do the Japanese do another wave or even 2?

Assuming they DO do another wave, they'll likely get the dry dock and the oil tanks, as well as further damaging/destroying more ships. Couple that with more general clutter in PH and PH is largely out of business for months.

The US can shift a few carriers from the Atlantic, but that'll take time and they'll likely initially focus on screening the area between PH and CA and around HI. It'll be quite a few months before the US does anything offensive in the Pacific.

Among other things, there's no Doolitle Raid with its positive effect on US morale and the affects on the Japanese of defending more strongly.

In 1942, likely no Coral Sea, no Midway, and the Japanese hold and build up Guadalcanal.

In general, the Japanese probably take Port Moresby and solidify a few other islands before they have to focus on new US forces.

The movement of the carriers and other ships from the Atlantic to the Pacific also has some effects in the European theater -- less support for Torch, Malta, etc.
One of the more often repeated myths is that the channel could be blocked by a single ship. Not the case. The channel had a usable width of 400 yards with an undredged depth of 35 feet, even on the margins.
 
If Ranger and Wasp are pulled out of the Atlantic earlier to replace Lexington and Enterprise that means that fewer Spitfires are flown off to Malta in the case of Wasp and less air cover available for Operation Torch in the case of Ranger.

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Ninjad by Zeng He in Post No. 5.

Is it feasible to have Saratoga at Pearl Harbour when the Japanese attack too?

But OHOH if all 3 of the Pacific Fleet's aircraft carriers were at Pearl Harbour when the Japanese attacked...
  1. Where would their aircraft be?
  2. That is on the aircraft carriers or ashore?
  3. If the latter is there any possibility that their fighter squadrons can be scrambled to meet the Japanese?
  4. Or is the only difference that they get destroyed on the ground at the naval air station instead of destroyed in the hangars of the aircraft carriers?
 
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How about the IJN sends its 68 fleet subs into the Atlantic and target the USN carriers and warships there? They could refuel with disguised Japanese or German supply ships.
 

CalBear

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How about the IJN sends its 68 fleet subs into the Atlantic and target the USN carriers and warships there? They could refuel with disguised Japanese or German supply ships.
So send the SS force a MINIMUM of 13,000 miles, one way (assuming they deploy from the Marshalls, add 2,500 miles from Japan) a 52 DAY trip at an average of 10 knots, assuming all surface travel, no breakdowns or extended submergence, and including a trip around the Horn (going across the IO and around Africa is several thousand miles further) just to reach a patrol area? By the time one 40 day patrol and round trip was complete the boat would have to go into the Yard for a month long refit.

Seems a bit over-ambitious.
 
Salvaging carriers? I doubt it.

I would think that, if the carriers were the primary target, that salvaging them would be difficult to impossible. Carriers are not as robust as battleships, hence could possibly be chewed up more. Any that were sitting upright in the mud would look like they weren't sunk, and get more attacks. Also, new carriers can be built much faster than battleships, so I wouldn't expect as much urgency in refloating a mangled piece of steel that's possibly looking something like the Maine did in Havana harbor all those years ago.

Any that were worth salvaging would be repaired as fast as possible, of course.

Even with the channel as wide as it was, a ship sunk there would be a problem for navigation. And if a burning wreck was sideways, drifting out of control when it blew up and sank, it would be a mess. Wouldn't block the harbor, perhaps, but it would certainly inhibit operations--and the clearing operation would also be in the way.
 
Salvaging carriers? I doubt it.

I would think that, if the carriers were the primary target, that salvaging them would be difficult to impossible. Carriers are not as robust as battleships, hence could possibly be chewed up more. Any that were sitting upright in the mud would look like they weren't sunk, and get more attacks. Also, new carriers can be built much faster than battleships, so I wouldn't expect as much urgency in refloating a mangled piece of steel that's possibly looking something like the Maine did in Havana harbor all those years ago.

Any that were worth salvaging would be repaired as fast as possible, of course.

Even with the channel as wide as it was, a ship sunk there would be a problem for navigation. And if a burning wreck was sideways, drifting out of control when it blew up and sank, it would be a mess. Wouldn't block the harbor, perhaps, but it would certainly inhibit operations--and the clearing operation would also be in the way.

Just as bad as the lost ships would be if more people were killed--it takes time to train skilled crew, and carrier pilots are hard to come by. Would the pilots be on the ship, or ashore with their planes, when the ships are in port?
 
I agree with NHBL. The ships are likely to be damaged beyond repair. However, the same applied to some of the destroyers sunk at Pearl Harbour, but their machinery was salvaged and incorporated in new ships bearing the same names. That might be feasible with the aircraft carriers.
 

Geon

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So they get two decks. Enterprise and Lexington. Sara was en route to San Diego from Bremerton, scheduled to pick up her VF squadron which had just been checked out on the F4F while she was in refit.

That leave Sara, Ranger, Yorktown and Wasp, along with Hornet, which is still shaking down. At least two of the Atlantic fleet ship will have to stay put, probably Wasp and Ranger.

First thing that goes is the Wake relief effort. No chance. The early Marshall Islands strikes may be scrubbed. The Doolittle Raid just went from risk to unacceptable risk. Without the Doolittel Raid the U.S. will have three decks for Coral Sea. That might turn into a major U.S. victory or could remain that tactical draw of OTL.

From there forward it is likely close to business as usual. There is a chance that the Midway operation is taken off the table, since at least part of the justification for the operation was to prevent a re-occurrence of that Raid.

In which case the Japanese Navy remains a viable threat after June, 1942. That might end up taking the Guadalcanal offensive off the table for the time being. Imagine the Battle of Iron Bottom Sound with IJN carriers backing the fleet up!

The USN has to approach the Pacific Campaign with a great deal of caution until U.S. production helps replace the lost carriers from Pearl Harbor. In my humble opinion that give Yamamoto an extra 6 months to either secure his position or grab for more territory.
 
OK, so let's say Lexington and Yorktown are at Pearl Harbor. Does that mean that KB delayed their attack by 24 hours? If yes, doesn't that perhaps change the alert status?

Nevertheless, if everybody is home. Lexington is moored on the NW side of Ford Island, behind Utah and Enterprise is moored where Neosho was OTL (between California and Oklahoma), sitting at an angle to the battleships. This was their usual mooring spot when in port.

Lt. Nagai's force of 16 torpedo planes were designated for the carrier attack and he is approaching from the WNW (directly into the sun). 2 of 6 torpedoes launched at Utah hit the target (1 of the misses hit Raleigh), which shows the problems caused by attacking into the rising sun. So, let's say Fuchida recognizes the carriers early and notifies Nagai to attack carriers. I assume he would attack Lexington with 8 aircraft and loop the other 8 around to the south to attack Enterprise.

Overall, I believe the torpedo hit rate was 50% (including misses that hit another ship). Have seen a report that only 33% hit the target they were aimed at, but I think that is low. They apparently launched at the two easiest targets to find on their approach, In any event, from Fuchida's after action report, it looks like 12 of 21 (57%) torpedoes launched at Oklahoma and West Virginia were hits. So, perhaps reasonable to conclude that the probability of a hit was better for aircraft attacking from the East, especially those flying up the Southeast Loch. However, Fuchida knew all along that pilot skill was always a factor in their testing and rehearsals (as expected). I would just note that OTL, part of the Nagai group flying around the South end of Ford Island attacked up the main channel and launched torpedoes at Oglala (mistaken for a BB) and obtained 1 of 5 hits (20%), a torpedo passing under the Oglala hit the Helena. Interesting that the 57% hit rate was the Murata force, while the two attacks attributed to the Nagai force had success rates of 33% and 20% respectively.

Because of the angle of her berth, attacking Enterprise requires assembly over Hickam Field and an approach over the Navy yard which is less than ideal, and probably requires a higher angle of attack. If they approach up the SE Loch and veer left, they do not have a beam-on shot. Not a good percentage approach for the Nagai group, which was not all that successful OTL. Bigger targets in this scenario, but does the Nagai force do significantly better against the carrier targets than OTL? If so, by how much? I would guess that 3-4 torpedo hits on each would put them on the bottom (in about 40' of water). So let's say they get sunk.

Does Fuchida change the attack plan due to the presence of the carriers? I doubt it, because the attack plan already had that contingency and allocated 16 torpedo planes to the carriers. He does have 36 dive bombers with 250 kg general purpose bombs in the second wave allocated to shipping targets. He would probably allocate some number of those to the carriers for sure. How destructive would they be and what would their hit rate be? Enterprise is certainly going to be shrouded in smoke.

Does this necessitate the 3rd strike? It is my understanding that Fuchida and Genda wanted it in the first place, but do they get it? If Nagumo now knew where the carriers were at Pearl Harbor does he relent? And, if so, how much of the smaller 3rd wave is allocated to shipping versus infrastructure? Even if, I do not buy the premise that the Fuel farm is lost for a year. The article referenced talks about replenishment oilers, not the tankers used to supply PH (reasonable mistake for a USAF officer). Operational reach is a different issue than the ability to rebuild and resupply a fuel depot at PH.

IMHO, it is hard to imagine the US would not make a significant effort to salvage the carriers. I would bet it receives their highest priority. Are they un-repairable? I do not think that is clear at all even though some have declared that would be the case. The aircraft on board would not be fueled in port, so no raging gasoline fires. 500lb GP bombs are not that destructive, and while many label the wooden-decked US carriers as having the proverbial glass jaw, the fact is that their hanger deck is their strength deck. As a result, the GP bombs are not likely to penetrate into the engineering spaces or magazines.

What is the effect on the war? Not as much as one might think even if the carriers can not be repaired. The Pacific Fleet would probably have three carriers available for Midway in any event (assuming it still happens). Port Moresby probably falls and perhaps there is no US attack on Guadalcanal. This really does not change much, and in my opinion if the Japanese want to expand further during this carrier gap, "be my guest". They have already exceeded their logistical reach, so placing more troops in more distant places only makes things more difficult for them in the long run.

Regardless of the 3rd wave or carriers, the Japanese accomplished their goal (which was simply to prevent the US fleet from attacking the flank of their Southern operations). The fact that it wasn't going to happen in any event being irrelevant.

Even if Moresby falls, does that prevent US troops and supplies from reaching Australia? No!

Does that prevent the flow of supplies to the DEI? No, it was already impossible.

Midway? Why would Yamamoto not be even more bold? Pacific fleet would have 3 carriers before that date. Not sure how this battle goes away.

Does that prevent the US from attacking Westward in 1942? First, they didn't have much reach to begin with so the major offensive crossed off the list is Guadalcanal, and should make the Doolittle raid too risky. What about Kwajalein? That actually fits better with Navy plans anyway and scratches the "do something" itch; and it is within range of the West Coast.
 
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Even if the American carriers don't sink, the damage caused by bomb hits and the resulting fires could be enough to render them CTLs.
 
Depends if they've got avgas or munitions onboard.

IIRC, the Japanese carrier Ryuuhou had neither when she was attacked in port in March 1945, and yet the damage was so severe that the IJN declared her a total loss. Not that it mattered much, seeing as how at that point the IJN had been totally stripped of planes, pilots, and fuel.
 
Would the avgas or munitions be offloaded? They aren't in harbor to enter drydock, just for a week or so before the next sortie? I'd expect that, espeically with a war warning, the supplies would be on board, thought the planes aren't.
 
No one has mentioned the escort carriers. If two fleet carriers are lost on the first day of the war could there be a push to get the CVEs in action earlier? Perhaps they could patrol around Hawaii? If there is still a Gaudalcanal landing the CVEs could help cover the beachhead. The bad thing is you get an earlier version of Taffy 3's fight at Samar.

Something else to remember is this: By the end of 1942 the US Navy only had Enterprise left in the Pacific OTL. The US still hung on.
 

nbcman

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Assuming the 3 PacFleet CVs were lost, there could be a push to perform the 2-4 XCV commercial liner conversions which were rejected IOTL to get those ships converted in a 180-360 day time frame to bridge the gap until the Essex class CVs were widely available.
 
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No one has mentioned the escort carriers. If two fleet carriers are lost on the first day of the war could there be a push to get the CVEs in action earlier? Perhaps they could patrol around Hawaii? If there is still a Gaudalcanal landing the CVEs could help cover the beachhead. The bad thing is you get an earlier version of Taffy 3's fight at Samar.

Something else to remember is this: By the end of 1942 the US Navy only had Enterprise left in the Pacific OTL. The US still hung on.

SARA rejoined the Big E in December 1942.
 
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