WI: USN encounters IJN on 6th Dec. '41?

[Look More Closely Later]

What if (most of) the battleships of the USN Pacific Fleet are out on some sort of exercise/manoeuvres when, on the 6th of December, 1941 (east of dateline, time-zone) they encounter the IJN Carrier Fleet in international waters?
Assume the USN capital ships present are:
Tennessee, California (Tennessee class); Nevada, Oklahoma (Nevada class); Maryland, West Virginia (Colorado class)
Also assume 1 heavy cruiser:
New Orleans (New Orleans Class)
Also assume 4 light cruisers:
Honolulu, Phoenix (Brooklyn class); St. Louis, Helena (St. Louis Class)
Also however many destroyers, sea-plane tenders, submarines, and so forth might be appropriate and available.

(As far as I know, Pennsylvania is likely in dry dock at this point, and the heavy cruiser San Francisco is awaiting overhaul, as in the OTL. For the purposes of this timeline Arizona is also at Pearl, having some sort of maintenance work carried out in her magazines. I take Lexington and Enterprise to be off making their OTL deliveries of planes to other places.)
Edit:
In case it's important, the USN force is under the command of vice-admiral William S. Pye.
*****
Points that seem to me potentially salient:
The encounter takes place in international waters; the USN almost certainly aren't expecting to find six Japanese carriers plus surplus other ships wherever it is on the Carrier Fleet's approach that the USN encounter them, but (as far as I know) technically the Carrier Fleet hasn't committed an act of war simply by being here, however suspicious their presence may seem to the USN.
The Japanese are not at war with the USA... yet. If the Carrier Fleet attack now, then they provoke a state of war perhaps twenty four hours ahead of all the attacks which are scheduled to occur in the Philippines, in Thailand, on Malaya, on Guam, on Wake, etc, etc. Pearl Harbour itself will also go on alert, making any attacks on ships or facilities there very difficult.
Most of the capital ships (six out of eight of the USN battleships) which are the Carrier Fleet's primary targets are sitting here in front of them. If the IJN don't attack now it will be an unknown length of time before they return to Pearl.
The USN are very obviously not sitting ducks in port, but under steam and fully manned. Their immediate air-cover is minimal however.
From an IJN perspective, due to the encounter taking place, even if they do nothing the IJN has lost some of the surprise which it might hope to benefit from for any raid on Pearl Harbour, as their presence is sure to be noted in the area, and the Americans may be on a heightened state of alert for possible trouble for the next few days.
*****
Thoughts?

 

[johnboy]

What if (most of) the battleships of the USN Pacific Fleet are out on some sort of exercise/manoeuvres when, on the 6th of December, 1941 (east of dateline, time-zone) they encounter the IJN Carrier Fleet in international waters?
Assume the USN capital ships present are:
Tennessee, California (Tennessee class); Nevada, Oklahoma (Nevada class); Colorado, Maryland, West Virginia (Colorado class)
Also assume 4 light cruisers:
Honolulu, Phoenix (Brooklyn class); St. Louis, Helena (St. Louis Class)
Also however many destroyers, sea-plane tenders, submarines, and so forth might be appropriate and available.

(As far as I know, Pennsylvania is likely in dry dock at this point, and I assume the other Pennsylvania class, Arizona, is back at Pearl so there's something there 'just in case'. I take Lexington and Enterprise to be off making their OTL deliveries of planes to other places.)
*****
Points that seem to me potentially salient:
The encounter takes place in international waters; the USN almost certainly aren't expecting to find six Japanese carriers plus surplus other ships wherever it is on the Carrier Fleet's approach that the USN encounter them, but (as far as I know) technically the Carrier Fleet hasn't committed an act of war simply by being here, however suspicious their presence may seem to the USN.
The Japanese are not at war with the USA... yet. If the Carrier Fleet attack now, then they provoke a state of war perhaps twenty four hours ahead of all the attacks which are scheduled to occur in the Philippines, in Thailand, on Malaya, on Guam, on Wake, etc, etc. Pearl Harbour itself will also go on alert, making any attacks on ships or facilities there very difficult.
Most of the capital ships (six out of eight of the USN battleships) which are the Carrier Fleet's primary targets are sitting here in front of them. If the IJN don't attack now it will be an unknown length of time before they return to Pearl.
The USN are very obviously not sitting ducks in port, but under steam and fully manned. Their immediate air-cover is minimal however.
From an IJN perspective, due to the encounter taking place, even if they do nothing the IJN has lost some of the surprise which it might hope to benefit from for any raid on Pearl Harbour, as their presence is sure to be noted in the area, and the Americans may be on a heightened state of alert for possible trouble for the next few days.
*****
Thoughts?

Colorado can not be there-is on the US West Coast. The Japanese must attack. It is a golden opportunity to not just ground, but sink the US battleships and promises to be an even worse naval disaster for the USN with an even greater loss of life.

IN terms of the overall war, if anything it's a setback for the Japanese. They destroy no aircraft on the ground, SE Asia get an extra days warning and a series of ships that played little offensive role in the war are sunk and the US public are even more outraged. Sad news for the men involved, though.

 

[Look More Closely Later]

Colorado can not be there-is on the US West Coast. The Japanese must attack. It is a golden opportunity to not just ground, but sink the US battleships and promises to be an even worse naval disaster for the USN with an even greater loss of life.

IN terms of the overall war, if anything it's a setback for the Japanese. They destroy no aircraft on the ground, SE Asia get an extra days warning and a series of ships that played little offensive role in the war are sunk and the US public are even more outraged. Sad news for the men involved, though.

Strike Colorado then. Will correct that in a moment. For some reason it's listed on a website I checked as being at Pearl on the 7th, but obviously that's not the case...

 

[HMS Warspite]

Technically the two forces would just say: "hello" to eachother and go their own way after that, since Nagumo was under strict orders to wait for the signal on the planned time and date, before opening an engagement with the USA. As Nagumo was a conservative "by the book" type of commander, he would follow orders to the letter. One big advantage would be he already would have known were the USN Battleine would be making things easier, for the Japanese, once the final order was given to strike, resulting in a USN loosing more ships permanently, as a fleet at sea cannot be salvaged that easily, once sunk.

 

[muskeg13]

Pearl Harbor, and possibly the Philippines would not have occurred as it did. With the element of surprise completely lost, Nagumo would be forced to break radio silence and call off the attack. At the least, the U.S. battle fleet would have detached a cruiser force to shadow and report the location of the Japanese fleet as the U.S. main body made their way back to Hawaiian waters ASAP. Meanwhile, long range Army bombers and Navy PBYs from Midway/Wake and Hawaii would acquire and also shadow the Japanese fleet until they steamed out of range, only to be further shadowed by any USN subs that could be vectored in to continue the shadow.

Who knows? Maybe the Japanese Ambassador could deliver the declaration of war before war actually breaks out?

 

[Carl Schwamberger]

Technically the two forces would just say: "hello" to eachother and go their own way after that, since Nagumo was under strict orders to wait for the signal on the planned time and date, before opening an engagement with the USA. As Nagumo was a conservative "by the book" type of commander, he would follow orders to the letter. One big advantage would be he already would have known were the USN Battleine would be making things easier, for the Japanese, once the final order was given to strike, resulting in a USN loosing more ships permanently, as a fleet at sea cannot be salvaged that easily, once sunk.

Actually no. The Pacific fleet and US Army units in the Pacific had been issued a order to consider any Japanese encountered as hostile and to attack on sight. I cant recall the exact date this order was issued, but it came shortly after negotiations collapsed in November. This order was similar to the 'attack on sight' order given to the USN for enforcing the Atlantic nuetrality zone against Axis warships. Hence the attacks on German submarines previous to the German DoW on the US in 1941.

 

[Asami]

And if the Japanese are floating really close to American waters, wouldn't that raise a flag of alarm in the American mind?

 

[Sharunaku]

Actually no. The Pacific fleet and US Army units in the Pacific had been issued a order to consider any Japanese encountered as hostile and to attack on sight. I cant recall the exact date this order was issued, but it came shortly after negotiations collapsed in November. This order was similar to the 'attack on sight' order given to the USN for enforcing the Atlantic nuetrality zone against Axis warships. Hence the attacks on German submarines previous to the German DoW on the US in 1941.

So in this scenario, the US will be the aggressor? Would it be only a show-of-force "border skirmish" or will US declare war on Japan?

 

[The Kiat]

American warship air defenses weren't exactly top notch in 1941. Those ships repaired after the attack ended up in Bremerton being refitted with more AA guns (among other things).

And if the Japanese are floating really close to American waters, wouldn't that raise a flag of alarm in the American mind?

Not if the warning is lost in the gears of buearucracy, like those from Oahu's radar station. All it takes is for one person to decide not to pass on the intel and a wrench appears in the works.

 

[Geon]

Two Options

Two possibilities here that could occur.

1. Nagumo decides surprise has been lost and turns the attack force around. There is no day of infamy. On the plus side the U.S. does not enter the war at this point, whether it would later is open for debate. The Japanese move into Malaysia, Burma, Hong Kong, etc. goes ahead minus the attacks on the Philippines which are aborted in order to prevent the entry of the U.S. into the war. This delays U.S. entry into World War II by several months. Given anti-war sentiment at home FDR would probably not declare war to save British interests (the anti-war faction claimed that Britain was willing to "fight to the last drop of American blood"). Eventually it is likely German submarine attacks force FDR to finally request a declaration of war but the war doesn't receive anything like the support it does in OTL since we have no outrage from a surprise attack on Pearl Harbor and no approx. 3,000 servicemen and civilians dead. Lack of U.S. support means the British have to endure several months more of a crippling submarine blockade and Russia likewise has no Second Front until later in the war. This will probably mean a prolonged World War II.
2. Nagumo decides to attack the U.S. force rather then totally waste the moment. Since the U.S. force has no carrier support the attack by Nagumo is successful. Most of the U.S. force is sunk, this time with no chance of recovery of any of the ships lost, and possibly a much larger loss of life. As indicated earlier the planes at Pearl Harbor are not destroyed which means the U.S. still has an air strike force. It is possible they could be readied and launched if word got back to PH that an attack was under way. How successful they would be remains to be seen. In any case FDR gets a "day of infamy", just in a different way from OTL. How things go from here I leave to further discussion.

Geon

 

[marathag]

U.S.S. ENTERPRISE

At Sea
November 28, 1941​

BATTLE ORDER NUMBER ONE​

1. The ENTERPRISE is now operating under war conditions.

2. At any time, day or night, we must be ready for instant action.

3. Hostile submarines may be encountered.

4. The importance of every officer and man being specially alert and vigilant while on watch at his battle station must be fully realized by all hands.

5. The failure of one man to carry out his assigned task promptly, particularly the lookouts, those manning the batteries, and all those on watch on the deck, might result in great loss of life and even loss of the ship.

6. The Captain is confident all hands will prove equal to any emergency that may develop.

7. It is part of the tradition of our Navy that, when put to the test, all hands keep cool, keep their heads, and FIGHT.

8. Steady nerves and stout hearts are needed now.​

G. D. MURRAY,
Captain, U.S. Navy
Commanding​

Approved: November 28, 1941.
W. F. HALSEY,
Vice Admiral, U.S. Navy,
Commander Aircraft, Battle Force​

 

[marathag]

Given Battle Order Number One, don't you think a Task Force that included most of the Battle Fleet would have had similar orders?

 

[Orry]

If the Americans are in sight of the Japanese Carriers

And the Americans have orders to treat them as hostile

The Carriers are toast......

If its Japanese spotter planes that locate the American Battleships they are toast....

 

[phx1138]

Nagumo decides surprise has been lost and turns the attack force around. There is no day of infamy.

IMO, the most likely outcome.

The Japanese move into Malaysia, Burma, Hong Kong, etc. goes ahead minus the attacks on the Philippines which are aborted in order to prevent the entry of the U.S. into the war.

Unlikely, since the P.I. were a clear threat to SLOCs for the Southern Op, hence the need to attack the U.S. in the first place.

Eventually it is likely German submarine attacks force FDR to finally request a declaration of war but the war doesn't receive anything like the support it does in OTL

This also seems a very likely outcome.

However, IMO, the best outcome for Britain is the U.S. not entering the war at all. That way, all the supplies otherwise destined for U.S. forces are available for Brit/Commonwealth...

Lack of U.S. support means the British have to endure several months more of a crippling submarine blockade

Given U.S. involvement cost Coastal Command dozens of precious VLR Liberators OTL, this scenario, by making them available, is better for Britain, not worse.

This will probably mean a prolonged World War II.

That is far from certain.

possibly a much larger loss of life.

Possibly? It's likely to run upwards of 10000.

U.S. still has an air strike force. It is possible they could be readied and launched if word got back to PH that an attack was under way. How successful they would be remains to be seen.

And many obsolete & obsolescent aircraft remain in U.S. service that were otherwise replaced by P-38s, so not an unvarnished good.

 

[Dain]

Actually no. The Pacific fleet and US Army units in the Pacific had been issued a order to consider any Japanese encountered as hostile and to attack on sight. I cant recall the exact date this order was issued, but it came shortly after negotiations collapsed in November. This order was similar to the 'attack on sight' order given to the USN for enforcing the Atlantic nuetrality zone against Axis warships. Hence the attacks on German submarines previous to the German DoW on the US in 1941.

Woha. You learn something new every day.
This policy sounds very aggressive. I'm not certain how this would even be possible while Japan and USA still consider themselves at peace. Where there any incidents prior to Pearl Harbor caused by this?

 

[Look More Closely Later]

Admiral in Charge, USN

In case it's pertinent to the outcome, let's say that the admiral in charge of the U.S. Force encountering the IJN carrier fleet is vice-admiral William S. Pye, who as far as I can determine was the commander of the USN Pacific Fleet 'Battle Force' at the time. (Will update the opening post with this.)

 

[Look More Closely Later]

Warning issued

Woha. You learn something new every day.
This policy sounds very aggressive. I'm not certain how this would even be possible while Japan and USA still consider themselves at peace. Where there any incidents prior to Pearl Harbor caused by this?

Apparently the Pacific Fleet C-in-C received a warning on 27th November, 1941:

NEGOTIATIONS WITH JAPAN APPEAR TERMINATED. THIS DISPATCH IS TO BE CONSIDERED A WAR WARNING ... AGGRESSIVE ACTION EXPECTED BY JAPAN IN THE NEXT FEW DAYS.

Link
Admiral Halsey appears to have been informed of it and to have instructed his force delivering planes to Wake to act as Marathag indicated.

 

[Carl Schwamberger]

Woha. You learn something new every day.
This policy sounds very aggressive. I'm not certain how this would even be possible while Japan and USA still consider themselves at peace. Where there any incidents prior to Pearl Harbor caused by this?

No incidents. There were other messages to the US commanders in the Pacific previously that gave a context for this. Also general guidance from Washington meant the US military was operating on its own turf & nowhere near Japanese bases. ie: The US 4th Marines and the Asiatic squadron were already withdrawn from China. The embargos had caused all US flagged ships to leave Japanese waters the previous summer. Unless a Japanese ship came in range of a US base there was little chance of anything happening in December. Basically the US in the Pacifc had spent the autum months pulling back into a defensive stance around its most important bases.

This is why the 6th December message from Singapore that a Japanese fleet had been sighted headed south from Indochina caused such consernation in the White House & War Dept. The only explanation for a Japanese convoy at that location and course would be a attack on Maylasia. This report was the final trigger for sending the failed/late 7 Dec warning to Pearl Harbor.

 

[Carl Schwamberger]

In case it's pertinent to the outcome, let's say that the admiral in charge of the U.S. Force encountering the IJN carrier fleet is vice-admiral William S. Pye, who as far as I can determine was the commander of the USN Pacific Fleet 'Battle Force' at the time. (Will update the opening post with this.)

You are correct. Pye was the next guy in line of command at PH, and the commander of the fleet at sea there.

 

[TFSmith121]

Remember, December in the North Pacific is generally

NOT "good flying weather"... certainly not the farther north one is, even today, and more so in the 1940s.

Depending upon when this encounter takes place during the Japanese approach to Oahu (on Dec. 6 they were probably within ~400 miles nne of Kauai), and (huge IF) the US force is truly ready to shoot on sight (as the Atlantic Fleet was at the time of the Kearny and Reuben James incidents), the Japanese could suffer heavily ... carriers rarely did well in gunnery actions, after all.

Just ask Glorious and Gambier Bay...

IIRC, Nagumo's orders were to abort if the IJN task force was discovered east of the deadline up to a certain date; I do not recall if it was the date of the attack, or prior, however.

Best,