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Topic: Recovery Plan 2, About 10 miles southwest of Pearl< Next Oldest | Next Newest >
 Post Number: 1
Ken Hackler Search for posts by this member.


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PostIcon Posted on: Aug. 10 2002,1:11   Ignore posts   QUOTE


Plan 2 for recovering the midget submarine crews, if not the boats themselves, isn't known for certain. What is known with certainty is that the Japanese were nothing if not thorough. They believed in planning everything to such a degree that if something appears to be too simple, it probably isn't the right answer.

That's the case here. A single recovery plan was too simple for the IJN in 1941, therefore it isn't right.

Plan 1 was the Lanai Island rendezvous, as previously discussed. However, it is simply not in character with the Imperial Japanese Navy to leave it at one plan for recovery. After all, even the aircrews had three possible recovery options. For the aircrews, the first was obviously to land back on their carriers. The second option was to ditch their planes in the ocean near one of the lifeguard submarines north of Oahu. A chart captured from a crashed plane shows three such Japanese submarines. One of the three submarines was actually overheard on December 7th transmitting a radio message, and physically sighted off the north shore of Oahu on the next morning. The third option for the aircrews was the island of Niihau, quite some distance west of Oahu. A Japanese fleet submarine was assigned to "hang out" near the island and watch for aircrews in need of rescue. One fighter did go there, and the pilot created quite a stir before being killed by a local man.

Knowing this, why then has no one ever discussed the other options for recovery of the midget submarine crews? I think that's because the midget submarine portion of the attack was such a tiny part of the plan as a whole, and partly because the submarine crews perished during the attack with the sole exception being Kazuo Sakamaki.

None of the documents recovered from Sakamaki's boat specifically said anything about other recovery plans, but the large-scale chart found in his boat has two important clues to the alternates. These clues, when viewed in conjunction with information from other sources, allow us to make a fairly good reconstruction of the plans.

First, let's assume that the Japanese HAD alternate plans for the recovery of the midget crews. After all, ADM Yamamoto specifically required planners to make "every effort to recover the crewmen." Also, the aircrews were given three options, so the submarine crews should have had more than one.

What then could the midget submarine crewmen realistically do? Their boats were small and slow compared to the U.S. warships that would be trying to sink them, so they had to depend upon careful planning and stealth. They also had to contend with batteries that were barely sufficient to get them to Lanai Island once they'd completed their attacks inside the harbor. Any recovery plans had to consider these very important factors.

We know about the primary recovery point at Lanai Island, but what if a midget crew couldn't make it due to battle damage, mechanical problems, or operational delays (i.e., dodging U.S. destroyers). They had to be able to go someplace close to Oahu because of battery limitations. Close to Oahu was dangerous for the obvious reason that U.S. ships would be zipping angrily about for many months following the attack. Therefore, they had to make use of the only cover they had - darkness.

Submarines, either the full-size fleet boats or the midgets, had a small conning tower, which  presented a tiny silhouette that was difficult to see at night. They could surface fairly close to an island for a limited amount of time, provided they did so when the moon wasn't too bright. This wasn't difficult, since even on a night when the moon was full it was not out the entire night.

We also know that the mother submarines had been instructed to stay in the vicinity of Oahu during the daylight hours of December 7 rather than proceeding directly to Lanai Island as soon as they launched the midgets. They were also ordered not to attack American ships, since that would give away their positions.

Why these two orders? Perhaps the answer is on Sakamaki's chart.

The large-scale chart taken from his boat is contained in both the Army Pearl Harbor Board (APHB) and the Hewitt Inquiry. Reports of both are contained, in their entirety, in the Joint Congressional Hearings. The copy of the chart contained in the APHB is smaller than that in Hewitt's report, but it is easier to read.

The chart shows the I-24's intended approach to the launching point southwest of the Pearl Harbor channel entrance, passing about 5 miles south of Barbers Point on a course of 092. There are two release points for Sakamaki's midget, one bearing 225 (045 inbound) from the channel, and the other at 220 (040 inbound). Obviously, they didn't hit the intended launching point bearing 045 exactly, so they drew the new (040) track line at the last minute showing Sakamaki his course to the entrance buoys.

The Japanese followed the standard practice (still used today) of indicating courses along a track line as a number (such as 040) contained inside an elongated semi-circle that had a tail on it indicating the direction of travel. See the drawing below for examples. The drawing is the center portion of the small-scale chart found in Sakamaki's boat, and shows his intended trip around Ford Island. You can see his intended courses laid out counter-clockwise, with the direction given in degrees contained inside the semi-circles I just described.

Navy Historical Center photograph 80-G-413507

Notice also that there are other lines that run from his intended track, usually at a turn, to some point on land. These are bearings for visual sightings on landmarks so Sakamaki would know where to turn. They are not intended courses - they just tell him where he is. Note that those visual reference bearings are also contained in elongated semi-circles, but they don't have the tails pointing in the direction of travel.

Sakamaki, or the Navigator on the I-24, laid out his intended track to the channel entrance buoys using the same conventions. However, and this is important, they also listed the reciprocal (opposite) bearing for his inbound course. They listed it not as a bearing for a track, but rather as a visual bearing for a fix.

I find that very strange. There is nothing but water south of Oahu, so why have a "visual" bearing when there is nothing to see "visually"?  The answer is obvious - the mother submarine was there most of the day.

The bearing into Pearl for Sakamaki was 040. The reciprocal bearing was 220. In a pinch, Sakamaki could run back down that track about 10 miles to (hopefully) find the I-24. That wouldn't work during the day, of course, because too many U.S. aircraft and ships would be in the area. However, it would work once the sun went down. That's a major problem though. The mother subs were supposed to be at the Lanai Island rendezvous sometime between midnight and 3 a.m., so there wasn't time for them to hang around much after sundown. Therefore there had to be something else.

The mother subs were essentially a "daytime emergency" contingency, and one that would hardly have worked.


Two other fleet submarines, the I-68 and I-69, were ordered up to that general area on the evening of December 7, and basically they took the place of the I-24. Keep in mind that the primary mission of the I-68 and I-69 was to sink U.S. ships, but the lifeguard mission for aircrews was part of their orders. It doesn't take a large leap to assume that the midget crews were included in that lifeguard mission.

It also meant that all five midget crews had to know about the I-68 and I-69 being there, otherwise it would have done them no good. I suspect that Sakamaki was supposed to commit that information to memory, for security reasons,  rather than writing it down. Not having the rendezvous sites shown on the charts meant that the U.S. Navy would have a hard time knowing where to find the other subs if one of the charts fell into the "wrong" hands. Midget C did fall into the wrong hands, along with Sakamaki's charts, but U.S. Navy intelligence officers were busy looking for Japanese carriers and didn't pay a lot of attention to Sakamaki's charts at first.

It is lucky for Sakamaki that they were too busy to examine his charts closely, since he made the mistake of writing the reciprocal bearing down on his inbound track, a bearing that would only have had one possible reason for being there.

He also made the mistake of making two entries on the chart that gave away the 3rd contingency plan. That was an absolute last-ditch plan, and is discussed in the next topic.

Edited by Ken Hackler on --

Ken Hackler
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