WI: Pearl Harbor Had Been a Sea Battle

Delta Force

Banned
What if instead of the IJN striking Pearl Harbor in a surprise attack, the United States had a day or two of notice and sortied to meet them? The IJN fleet had six aircraft carriers but only two battleships, two heavy cruisers, one light cruiser, nine destroyers, and twenty-three submarines. The USN fleet had no aircraft carriers (or potentially one, if Enterprise participates), eight battleships, two heavy cruisers, six light cruisers, thirty destroyers, and four submarines. The USN also has the support of land based aviation in Hawaii, and the advantage of operating near its own naval base, while the IJN was operating near the edge of its endurance.

Would the USN be able to prevail in such a battle despite its deficiencies in aircraft carriers, or would the nightmare scenario posited by Admiral Nimitz occur, with the USN suffering the worst defeat in its history, losing most of the Pacific Fleet and 20,000 men?
 

sharlin

Banned
The Japanese could simply run from the US surface ships. The big gun's were all limited to 21 knots, thats their max speed, no changing that.

Even with ground based air support the USN is at a serious disadvantage. What would probably happen is that instead of being salvaged the battleships are sunk in deeper water with far more casualties.
 
It depends.

Here's the Ameriwank version:

If... somehow... the US gets pretty good knowledge of the IJN plan in detail (bearing in mind that Nagumo did not approach on the expected least-distance bearing from the Mandates) on about Nov 27th after Kido Butai has sortied, then the ideal US plan will be to get the battlewagons into range of the Carrier Striking Force just as dawn breaks on the morning of the 7th, based on the outcome of S&G vs Glorious and the FAA attacks on the KM in Norway.

0607 Hawaiian twilight
0610 Kido Butai commences first wave launch
0630 Horizon visible at Kido Butai position, assuming I understand how these sunrise calculator apps work
0725 Sunrise at Kido Butai position.

If Kimmel gets it absolutely perfect, he should be approaching Nagumo from the south-west at dawn after the first wave has gone, get radar detection of the Japanese force and close, and then at about 0645ish will find the IJN silhouetted against the lightening eastern horizon at about 16000 yards, and give the order to open fire.

The gunnery duel is grossly unbalanced in favour of the USN; Nagumo will swiftly order the carriers to turn away and flee at best speed under a destroyer smoke screen, while Hiei, Kirishima, Tone and Chikuma fight on until sunk to buy time for the rest of the destroyer screen to launch a torpedo attack.

The probable outcome is that the battleships and cruisers are sunk outright, Abukuma and the 8 destroyers lose about half their number, and a carrier or two is sunk - fuelling and arming the second wave means that they are terribly vulnerable to any penetrating hit. On the US' side, it won't be as bad as Tassafaronga, but the Long Lances will be fired from outside the expected torpedo range and Anderson and Kidd will probably not take evasive action in time, resulting in perhaps three hits, spread out among the battleships, all of which are significant but not fatal, slowing the targets through flooding.

The carriers may have the speed to outrun Anderson's Battle Force, but Leary's CruDivs 6 & 9 will be able to hold them in range, and with the USN's 3:1 superiority in destroyer hulls available, Kimmel will be able to both keep some to screen the battleships and send others to help run down Nagumo.

Simply, no carrier will survive to launch the second wave, though sinking the IJN destroyer screen on the way will probably cost a few US losses as well.

Meanwhile, back in Hawaii, the first wave finds Opana Point and the other radar stations manned and operating vaguely properly, and Lt. Tyler is not expecting 6 B-17s but instead the 1st Air Fleet of the IJN. Accordingly, the Hawaiian Air Force is scrambled with priority going to intercepting the raids on the airfields - the level bombers going down the west coast of the island are slow and targetted with a P-36 force.

Fundamentally, it's down to how well the defenders manage their ground control - they aren't set up to defend Hawaii from an air campaign like Dowding and Park in 1940 Britain, and so their controllers will not be experienced in raid interception control. Fundamentally, though, the USAAF has 89 P-40 and 38 P-36 - Fuchida has half as many A6Ms as he faces P-40s, with 140 strike planes - he is going to be taking significant losses on the way in, though the number of attackers means that several dozen should attack unmolested even while their compatriots are being intercepted.

USN losses will probably be Pennsylvania, in dry dock, along with Cassin and Downes alongside, and probably Utah, and possibly the auxiliaries Oglala, Vestal, and Curtiss, just because there are so few targets for the Japanese with the majority of the fleet at sea. While the level bombers have the right weapons to attack the fuel tanks, they are unlikely to do so unless they are undisturbed by the USAAF pursuit planes and the first runs clearly destroy Pennsylvania and Utah.

With no carriers to return to, all of the IJN aircraft which survive will ditch.
 
Why doesn't the KB recall the attack on Pearl to attack the battleline?

Why would the faster Japanese battlecruisers choose to slug it out with three-four times their number of battleships? They are 8-9 kns faster

The only American ships that can close on the KB are the cruisers and destroyers - who would be slaughtered by the Hiei and the Kirishima. They have at best a 4 kn advantage - and this leaves the CA behind. With the CA it's around 2 kn

The recalled first wave air attack will be disorganised and Likely to be mostly ineffective - but second wave attacks will be deadly. Of course if the American cruisers and destroyers go haring off after the KB then they are likely to be picked off in the stern chase and the American battleline just lost alot of its AA support.
 
...

0607 Hawaiian twilight
0610 Kido Butai commences first wave launch
0630 Horizon visible at Kido Butai position, assuming I understand how these sunrise calculator apps work
0725 Sunrise at Kido Butai position.

....

I think perfection would be the US destroyers & light cruisers starting their torpedo attacks at approx 06:00. This disrupts the launch of the first strike & gets the Japanese destroyer screen to expend part of its torpedo load on the small ships. The two USN carriers standing off another two dozen miles to the west would have their strike groups in the air before 06:00 & ready to turn east when the destroyer attack starts.

The USN submarines would be deployed in a arc well to the east & north to harass any enemy moving in those directions. On Oahu the CAP stats at dawn with one fighter squadron aloft and the remainder on ten minutes ready alert. The recon would be enroute to patrol routes, and the bombers ready on ten minutes notice at 06:00. Bomb loads would be appropriate to 1941 US doctrine for attacking ships.
 
Why doesn't the KB recall the attack on Pearl to attack the battleline?

There was a Japanese plan for discovery of the US fleet outside the harbor. The strike commanders had signals & a rehearsed set of actions, so its is important the USN gets its attack started before the IJN airgroups can form aloft.

Why would the faster Japanese battlecruisers choose to slug it out with three-four times their number of battleships? They are 8-9 kns faster

IJN doctrine was for them to conduct a covering attack while the carriers withdraw.

The only American ships that can close on the KB are the cruisers and destroyers - who would be slaughtered by the Hiei and the Kirishima. They have at best a 4 kn advantage - and this leaves the CA behind. With the CA it's around 2 kn

At the distances implied in the post the two fleets are already in sight & range at first light. The IJN has the disadvantage of being silouetted by sunrise, the US fleet is backdropped by the approaching storm from in the west, and is oriented by its radar. There will be a minimum of a few minutes with both battle lines in range. How long that continues depends on how quickly Nagumo continues efforts to launch or decides to turn away & save the carriers. The US BB opening fire will certainly hasten such a decision.

The recalled first wave air attack will be disorganised and Likely to be mostly ineffective - but second wave attacks will be deadly. Of course if the American cruisers and destroyers go haring off after the KB then they are likely to be picked off in the stern chase and the American battleline just lost alot of its AA support.

If the appropriate air strikes are launched from the US carriers & Oahu there wont be much need for the US light ships to pursue in a disorganized manner. The torpedo attack groups should return to cover the battle line & prepare for further action.
 
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Still smacks a little too much of ASB foresight and IJN lead paint sipping for me

Wouldn't the cAP (if not the planes forming up) have a reasonable chance of detecting the approach of the American fleet?
 

sharlin

Banned
The IJN also had recon planes out as well, basically for the USN's gunline to get in range of the IJN's carriers...they'd have to be invisible.
 

Delta Force

Banned
Could the IJN really just steam away? Certainly their ships are fast enough to escape the Standard type battleships, but the fleet was on a very tight logistical budget and had to refuel at an island chain on the periphery of the Japanese Empire to refuel and reprovision instead of returning directly to the home islands.
 
As interesting sidenote in the above scenario the US would attack the Japanese without prior DOW - which would paint the US as agressor ;)

I put it to you that sitting your main carrier striking force off another nations main Pacific Base could only mean one thing and is a casus belli in its own right.
 
I put it to you that sitting your main carrier striking force off another nations main Pacific Base could only mean one thing and is a casus belli in its own right.

Yeah, somehow I see it being hard for Japan to say "Oh, we were just cruising innocently several thousand miles from home and all the sudden we were attacked by a whole bunch of battleships." Bullshit and the world knows it - You're right, there's only one reason they could be there and it certainly isn't a pleasure cruise.
 
Could the IJN really just steam away? Certainly their ships are fast enough to escape the Standard type battleships, but the fleet was on a very tight logistical budget and had to refuel at an island chain on the periphery of the Japanese Empire to refuel and reprovision instead of returning directly to the home islands.

The carriers would all do about 30 knots and would run for as long as it took to get out of range / night time and could then slow down change direction etc

However if the US knew about the carrier fleet remember that their was also 400 odd assorted aircraft on the island so it would be a combined attack - not just battle wagons - and the carriers certainly could not out run Aircraft!
 
What about if the Americans get 3 hours notice and sent out a flotilla of destroyers and a cruiser or two, and maybe make the Japanese panic as they had a group of ships coming towards them and this could possibly lead to a firing of torpedoes at the IJN ships.

This might actually help the Americans in the long run, as the Japanese might panic and send out some of their planes to attack the flotilla, and thus make the attack on pearl harbour less deadly. and by this point, you at the they least would have the AA guns on the battleships manned, thus, less of a complete whitewash. Not expert on pearl harbour , but being a Sunday, many officers would have been golfing, sailors hung-over. thus, lack of organisation, but the IJN fleet would need to be discovered a least 12 hours before to have a blue water battle
 
What about if the Americans get 3 hours notice and sent out a flotilla of destroyers and a cruiser or two, and maybe make the Japanese panic as they had a group of ships coming towards them and this could possibly lead to a firing of torpedoes at the IJN ships.

This might actually help the Americans in the long run, as the Japanese might panic and send out some of their planes to attack the flotilla, and thus make the attack on pearl harbour less deadly. and by this point, you at the they least would have the AA guns on the battleships manned, thus, less of a complete whitewash. Not expert on pearl harbour , but being a Sunday, many officers would have been golfing, sailors hung-over. thus, lack of organisation, but the IJN fleet would need to be discovered a least 12 hours before to have a blue water battle

My understanding is that it takes about 4 hours to light all the boilers from the standby one that is always lit and get enough steam to move for capital ships

However 3 hours is long enough to arm and fuel aircraft and set standing patrols as well as all ships to close up for general quarters with the AAA weapons on shore and on the ships fully manned and ready

Not having a free reign in the air and everything on the ground shooting at you is going to make the first wave many many times less effective than OTL

I seriously suspect that their would not be a second wave
 
Japanese spy overlooked?

What if instead of the IJN striking Pearl Harbor in a surprise attack, the United States had a day or two of notice and sortied to meet them?...
The Japanese had at least one spy in Hawaii, Takeo Yoshikawa. I think he might have noticed and alerted Tokyo if there was a sudden break in Pearl Harbour routine and preparations apparently started for a massive USN sortie in strength.
At that point I see two options for Tokyo:
1) Scrub the attack on Pearl Harbour altogether - it's supposed to be a surprise attack and it's clearly no longer going to be against an enemy who is unprepared. Events elsewhere may still possibly proceed as planned.
2) Notify the Japanese Carrier Force to change the plan for a 'decisive action at sea'. (If a sea-battle does take place the Japanese still have the odd nasty surprise up their sleeves such as their armour-piercing bombs, and the American casualties are potentially much higher than for the original timeline attack, since the American ships are all going to be fully manned and when a ship goes down there's likely no 'swim to shore' option.)
 
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Imagine the USN goes out on exercise. The carriers and most of the BBs come too. JP spies report this, and the Kido Butai catches the USN by surprise on the high seas...

the ships sunk at Pearl were easily refloated from the shallow bed of the harbor, but at sea they are lost forever.

Not only are BBs hit this time, but the CVs as well. If the Japanese keep their surprise, they can make this a devastating blow.

Though this requires so much luck that it's basically ASB :p
 
And the war still ends in mushroom clouds over japan. :)

Getting back on topic, the USN doesn't necessary need to sink the entire KB, it just needs to damage it sufficiently to allow light forces to attack it en mass.
 
Still smacks a little too much of ASB foresight and IJN lead paint sipping for me

Wouldn't the cAP (if not the planes forming up) have a reasonable chance of detecting the approach of the American fleet?

CAP went up at dawn. The US fleet approaches before light, & during a overcast. I cant recall if any CAP was launched before the first strike group or if it was all launched after.

The IJN also had recon planes out as well, basically for the USN's gunline to get in range of the IJN's carriers...they'd have to be invisible.

IJN doctrine was launch recon at earliest light. The could launch at night, but the increased risk, particularly in rough seas meant they usually waited until the pilots could see the water at takeoff. Bad joss to run into some other ships mast twenty seconds after leaving the Tones catapult :(

The Japanese had at least one spy in Hawaii, Takeo Yoshikawa. I think he might have noticed and alerted Tokyo if there was a sudden break in Pearl Harbour routine and preparations apparently started for a massive USN sortie in strength.

The Wiki article linked says Yoshikawa had no knowledge of the planned attack on PH. For some reason I dont think that is 100% accurate. However his reports were sent twice weekly via the Japanese consulates radio & I do not remember him having any provision for emergency or last minute communications. IIRC his last report was sent Friday & did mention the carriers were not present. His reports were forwarded from the diplomatic offices in Tokyo to the Naval Intelligence Service offices where they were reviewed and forwarded to the PH attack planning staff, or to Yamamotos HQ as appropriate. IIRC the news the carriers were not in PH was forwarded to Nagumo. Perhaps Glen could clarify that?

At that point I see two options for Tokyo:
1) Scrub the attack on Pearl Harbour altogether - it's supposed to be a surprise attack and it's clearly no longer going to be against an enemy who is unprepared. Events elsewhere may still possibly proceed as planned.
2) Notify the Japanese Carrier Force to change the plan for a 'decisive action at sea'. (If a sea-battle does take place the Japanese still have the odd nasty surprise up their sleeves such as their armour-piercing bombs, and the American casualties are potentially much higher than for the original timeline attack, since the American ships are all going to be fully manned and when a ship goes down there's likely no 'swim to shore' option.)

Here is a link to a English language summary of the Japanese plan for attacking PH & elsewhere: http://www.ibiblio.org/pha/myths/jm-097.html

As I read it Nagumos orders or guidance was to attack the US Pacific fleet where he found it. While the ideal location was seen as in PH the expectation was a attack at sea could be productive as well. Hence the submarines deployed around the Hawaiian Islands, and the air reconissance. If Nagumo finds the US fleet at sea odds are his staff will be whipping up a attack plan ASAP, or the strike leaders will be winging one aloft.

For comparison here is a link to Kimmels war plan: file:///Users/carlschwamberger/Desktop/War%20Plans/WPPac-46%20Kimmels%20Plan.webarchive

The core feature is Kimmel continued the War Plan Orange doctrine of avoiding any decisive battle until the 'offensive fleet' under construction was complete and ready for campaigning. That is in mid 1943, or some 18 months from Dec 1941. However Kimmels intent in this plan is supposed to be more aggressive in 'seeking opportunities' that some of the earlier versions of his predecessors. ie: Richardson wanted to keep the fleet on the west coast until ready for offensive operations. Hence his advising against rebasing the fleet at Oahu in early 1941.

...
Getting back on topic, the USN doesn't necessary need to sink the entire KB, it just needs to damage it sufficiently to allow light forces to attack it en mass.

Indeed. With a warning the more likely scenario is the main fleet is deployed to the SE of Hawaii, out of IJN air recon range, US submarines are deployed along likely approaches, and if the Japanese fleet is located a series of air strikes are launched. After a bloody and indecisive air battle including attacks on the empty naval base Nagumo would return to Japan frustrated.
 
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What about if the Americans get 3 hours notice and sent out a flotilla of destroyers and a cruiser or two, and maybe make the Japanese panic as they had a group of ships coming towards them and this could possibly lead to a firing of torpedoes at the IJN ships.

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The Japanese strike force launched from about 270 nm from Oahu. At 30 knots that is nine hours to reach the launch point, at 20 knots 13.5 hours. Realistically we are looking at some fifteen hours to reach a attack position, assuming the Japanese location is known.
 
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