The Enterprise on 12-07-1941 -- How Close?

[Sofa_King]

I’m trying to figure something out, and I was wondering if anyone would like to help me.

When the Japanese attacked Pearl Harbor at 0755 local time on December 7, 1941, one of their primary targets, the aircraft carrier Enterprise was so close to Oahu, returning to base after ferrying the ill-fated VMF-211 squadron to Wake Island, that it actually picked its way into the burning harbor that evening, reprovisioned, and snuck out before dawn on December 8. At least one American flyer from the Enterprise was killed that evening by jumpy American anti-aircraft gunners.

According to this site, Task Force Eight, Enterprise’s formation at 0700 on December 7 was at “Latitude 21-11, Longitude 161-00, about 200 miles to westward of Oahu.” An hour later, TF8 should have been about 20-25 miles closer.

This map shows the deployment of the Japanese air assets in the attack. As you can see, the first wave of Japanese high-altitude bombers made a “right hook” or a wide loop to the west before making their attack run. (Note-the “high-altitude bombers” were simply single-engine Kate torpedo bombers fitted with a large bomb and a fairly simple sight.)

I’m pretty sure it didn’t happen, but I’m wondering if it was possible for the Japanese high level bombers to spot Task Force Eight on its approach to Oahu just before the bombers’ attack. Here’s what I still need to figure out:

• Is that first citation using statute miles or nautical miles?

• What was the approximate surface distance separating TF8 from the high-level Kates at their closest approach?

• At what altitude were the Kates flying? (My first guess is probably close to 12,000 feet–I don’t think Kates had oxygen for flying much higher than that.)

• How do I calculate the horizon for a given altitude? (I should know this one, but it’s been a long time since I took trigonometry.)

We know that during the Battle of the Coral Sea, it was possible for flyers to briefly see the opposing fleets on opposite horizons at the same time. I’m wondering if something similar were possible for TF8 and the Japanese during Pearl Harbor. Thanks in advance for your help.

[tomndebb]

I’m afraid this site won’t help too much,
http://www.cv6.org/1941/1941.htm
but it does mention an aspect that you haven’t included: to the west and north of Hawaii there was the end of a serious weather front. My memory is that the Japanese launched in periods of alternating heavy rain and brief calms. You’ll have to figure cloud cover into your equations.

[SPOOFE]

I should mention that the title of this thread made me think it was about a Star Trek episode where the Enterprise travelled back in time…

[Whack-a-Mole]

…even if the bombers did spot the Enterprise I doubt they would have attacked.

Their main goal was Pearl Harbor itself. Had they attacked the Enterprise they would surely have alerted Pearl Harbor and the Japanese would have had nowhere near an easy time if they pressed the attack after sinking the Enterprise.

In addition the pilots were on strict radio silence again so as not to warn Pearl Harbor. They all took off with a mission in mind and that’s the only thing they were going to do once on their way regardless what they flew over on the way there.

By the time the strik force returned to the Japanese carriers the Japanese decided to skeedaddle. Their attack had gone better than they could have hoped for (somehow not realizing the importance of destroying the dry dock and oil storage that they failed to do). Even if they knew the Enterprise was out there they would now be facing a warned enemy with potential support from land based aircraft. Not to mention that land based aircraft would now be searching for their task force (actually I don’t think the US went searching for their task force at all but it would be the smart assumption to make from the perspective of the Japanese).

In the end it was best for the Japanese to mosey out of there (not counting a follow-up strike on other assets in Hawaii). At that point the US had what…three carriers?..in the pacific. After smashing the US fleet the Japanese felt those were a minor threat against their ships. Of course, carrier sea battles were still in their infancy and it was not understood (by anyone) just what three carriers could achieve. This was a lesson that would be driven home in the battle for Midway.

[warinner]

Whack-a-Mole wrote:

…even if the bombers did spot the Enterprise I doubt they would have attacked.

Their main goal was Pearl Harbor itself.

No, the target was the US Fleet. According to an interview with Mitsuo Fuchida, Adm. Nagumo’s air commander:

Question: If the American fleet had been at sea, how would the plan have been modified?

(Replies by FUCHIDA:)

(1) Had the American fleet sought to intercept our Task Force or had there been a significant threat to the attack as planned, we would have counterattacked.

(2) Had the American fleet left port we would have scouted an area of about 300 miles around OAHU and were prepared to attack. If the American fleet could not be located, we were to withdraw.

…

Question: Why was the air assault not continued, and why was it not followed up by surface units or by a landing?

(Note: This reply is based on the recollections of Comdr FUCHIDA, Mitsuo, Commanding Officer of AKAGI Air Unit at the time of the attack.)

(1) The object of this attack was to destroy the capital strength of the UNITED STATES PACIFIC Fleet and to delay any attack which it might make across the PACIFIC. Hence this
objective could be accomplished by air attack alone. Furthermore, since the whereabouts of the American task forces were unknown and since the chances of scouting them were small, in face of a possible counterattack in co-operation with the 50-odd remaining HAWAII-based large
airplanes, the advantages of a quick withdrawal were apparent. Consequently, no naval assault was undertaken.

Sofa King wrote:

I’m pretty sure it didn’t happen, but I’m wondering if it was possible for the Japanese high level bombers to spot Task Force Eight on its approach to Oahu just before the bombers’ attack.

This should answer your question regarding the altitude of the high-level bombers, the cloud conditions prevailing that day and your main question. Again, from the Fuchida interview:

Question: Explain the courses, and the reasoning therein, which the air units followed from the aircraft carriers to the targets.

Both the First and Second Attack Units proceeded directly from the carriers to OAHU. They flew at an altitude of 3,000 meters. (Dense clouds hung at about 2,000 meters that day, so the airplanes flew above them.)

Even had the cloud conditions not precluded sighting TF8, sighting the ships would have been iffy at best. I think there are a couple of factors that would have made it difficult to spot the task force. First, I’m not sure that TF8 would have been making over 20 knots. That’s a fairly high speed and a more economical cruising speed may have been used. A lower speed would have also meant a smaller wake and hence a smaller chance of being spotted. Another factor might have be what formation TF8 was sailing in. If TF8 was sailing in an anti-submarine formation, the Enterprise and its escorting would have been sailing in a wide formation and so would been easier to spot.

Given the difficulties that both the US and Japan had in locating and correctly identifying enemy fleets, I’d say it would have been long odds on Kido Butai spotting TF8 unless they were specifically searching for it.

Andrew Warinner

[Whack-a-Mole]

…and the reasoning for this lies in your own post and the cites you use:

Both the First and Second Attack Units proceeded directly from the carriers to OAHU. They flew at an altitude of 3,000 meters. (Dense clouds hung at about 2,000 meters that day, so the airplanes flew above them.)

Given that I’d say they were not looking for TF8 or any other ships at sea. Their primary goal was Pearl Harbor (and by that I mean the ships at anchor there…I apologize for not being more specific on this earlier). It would seem that surprise was of importance to them hence flying above the cloud layer and maintaining radio silence. Had they been serious about seekinf TF8 (or anything else at sea) they would do neither of these things so they could A) Spot the ships and B) Tell other planes that something was spotted and corrdinate an attack.

From the comments of Comdr. Fuchida I would guess that had they not found the bulk of the US fleet at anchor they would then have started spreading out seeking the US ships. Also, what is not clear from Comdr Fuchida’s comments are whether they would have sortied more planes after attacking Pearl had they spotted TF8. On the one hand smashing the US fleet was important and on the other getting the hell out of Dodge was also important (as supported by Fuchida’s comments). Given what seemed a fantastic success already and the threat posed by “50-odd remaining HAWAII-based large airplanes” I wouldn’t be at all surprised if they let TF8 go even if they spotted it.

When you stir a hornets nest its best not to hang around.

[warinner]

Whack-a-Mole wrote:

Given that I’d say they were not looking for TF8 or any other ships at sea.

But they were under strict orders to be on the lookout for any surface and air units. Consider Nagumo’s orders to Kido Butai:

While exercising strict antiaircraft and antisubmarine measures and making every effort to conceal its position and movements, the entire force (except the Midway Bombardment Unit) in accordance with special orders will depart as a group from Hitokappu Bay at a speed of 12-14 knots.

Carrier Striking Task Force Operations Order No. 1
11/23/41

And Nagumo did order reconnaisance patrols to take place:

c. Scouting Patrol

The reconnaissance seaplanes of the 8th Cruiser Division will take off at 0300 hours (on 12/7/41) and will carry out an extensive search of the waters between the enemy and the friendly forces and the waters adjacent to the two channels situated to the east and west of the Island of Oahu. They will observe and report the presence and activities of the enemy sortie force and enemy aircraft on counter-attack missions.

Carrier Striking Task Force Operations Order No. 3
11/23/41

Moreover, Nagumo had a submarine force in place off Hawaii specifically tasked with patrolling for US naval units.

And finally Nagumo himself ordered:

If the destruction of enemy land-based air strength progresses favorably, repeated attacks will be made immediately and thus decisive results will be achieved.

In the event that a powerful enemy surface fleet appears, it will be attacked.

Carrier Striking Task Force Operations Order No. 3
11/23/41

So Nagumo provided for a sea engagement as part of the Pearl Harbor attack. On the other hand, it’s clear that there is a fair bit of planning for the expected rather than the possible in Nagumo’s orders.

On whether Nagumo would have attacked TF8 if it was detected boils down to two considerations: (1) when TF8 was discovered and (2) Nagumo.

If TF8 was discovered before the launching of the first attack wave and assuming that the seaplane reconnaisance of Pearl Harbor informed him that the battleship fleet was present but the carriers were not, Nagumo would have had quite a problem.

Attacking Pearl Harbor would risk a counterattack from TF8. As far as Japanese intelligence could have told Nagumo, TF8 might have had more than one carrier since the Japanese did not know where the three carriers of the Pacific Fleet were located. On the other hand, attacking TF8 could allow the main US fleet to sortie from Pearl Harbor and attack. Nagumo might well have decided to cut and run without attacking anything.

Given the small time difference between the first and the second attack waves, I assume that Nagumo would not have opted to redirect the second Pearl Harbor attack wave to engage TF8. To do so would have invited a ‘order, counterorder, disorder’ situation.

So what have Nagumo done if TF8 was detected after the successful return of the two Pearl Harbor attacks? Nagumo was strongly urged by his subordinates, especially Fuchida, to launch a third attack of Pearl Harbor but Nagumo refused because the previous attacks had been wildly successful and Nagumo did not know the location of the US carriers.

But what if Nagumo did know where TF8 was? On one hand, you could argue that Nagumo’s ‘quit while you’re ahead’ reasoning was just as applicable and Nagumo would have skeedaddled. On the other hand, one could argue that Nagumo knew that Pearl Harbor posed no immediate threat to Kido Butai and here was an opportunity to concentrate six carriers against one and heap success on success. Yamamoto might have taken that gamble, but Nagumo arguably would not have, especially in light of Nagumo’s decisions in other actions. On yet another hand, Nagumo would have been faced with making a difficult decision in a short time. Who can say what he would have done?

Andrew Warinner