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Topic: Midget C - The I-24 Midget, Kazuo Sakamaki's very short war< Next Oldest | Next Newest >
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Ken Hackler Search for posts by this member.
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PostIcon Posted on: Jul. 28 2002,11:14  Skip to the next post in this topic. Ignore posts   QUOTE

Kazuo Sakamaki and his crewman launched their midget submarine - the HA-19 - from the fleet submarine I-24 shortly after 0330 on the morning of December 7, 1941. Their goal was to enter Pearl Harbor and launch their torpedoes at an American battleship. History had something else in mind for them, however.

The trip from Japan was largely uneventful, but there had been several incidents that were perhaps prophetic of the difficulties that faced Sakamaki. For example, he was washed overboard at least once, and was only saved by having tied a rope around his waist as a precaution.

Another accident nearly killed everyone on the I-24. She had a mechanical problem that prevented one of the ballast tank valves from closing properly. Water flowed freely into the ballast tank as a result, and the I-24 became too heavy and started going down. She went past 300 feet on the way to the bottom before the problem was corrected. Had she gone just a little deeper, all hands would have died and the submarine likely would still be listed as "missing." The 300 foot depth far exceeded the midget submarine's test depth, yet she managed to survive the ordeal somehow. One of her torpedoes was badly damaged, though, and had to be replaced.

Upon arrival off of Oahu, maintenance crews readied Sakamaki's HA-19 for her mission. They discovered at the last minute that the gyrocompass didn't work, and all attempts to repair it failed. Without the gyro, Sakamaki had to depend on visual sightings through the periscope to navigate. This was very difficult since the apperature on a midget submarine's periscope was tiny and it was night. The tiny apperature (the size of the glass viewing area) allowed in precious little light to begin with, but depending upon it in the night was practically suicidal.

Yet Sakamaki and his crewman decided to go anyway.

His midget had major problems from the outset. As soon as she was launched, Midget C was wildly out of control because her trim was so far off. Many people have written about Sakamaki's problems with the trim, but they almost always get it backwards. According to his book, Sakamaki was not trying to keep his boat from sinking, but rather trying to keep it from popping to the surface where it would be seen by U.S. forces. This statement is reinforced by the fact that Sakamaki had to add water to his trim tanks to make the boat heavier, something he would hardly do if she was already sinking. They also had to shift the lead weights, called "pigs", because the boat was stern heavy. All of the lead pigs were located in the forward portion of the boat when she was salvaged. As a matter of interest, the lead pigs were put on the boat in Japan to help trim her out after almost 15% of the battery cells had been removed. The weights were installed to offset the loss of weight caused by removal of the batteries. The battery cells had been removed from the forward battery.

Once the trim was corrected and Sakamaki had a moment to focus on the task at hand, he set course for the Pearl Harbor channel entrance. He checked the boat's progress through the periscope every 15 minutes or so, and found that she continued to go off course by about 90 degrees. He continually corrected the course, but the boat wandered off course every time he let her run on the midget submarine's primitive version of an autopilot (i.e., he tied the wheel in place).

One thing to remember here - the bad gyrocompass did NOT affect the stearing. They were not connected in any way. A bad gyro meant that Sakamaki had to continuously look where he was going, but it did not change the boat's course. The rudders were the only thing that could change the course, and they were operated pneumatically. Air pressure kept them in place.

Sakamaki would set the rudders to keep the boat on a certain course, but the rudders were either misaligned to begin with, or there was an air leak inside the boat that allowed the rudders to "drift". I think it was probably a combination of both - a mechanical misalignment as well as an air leak. Sakamaki mentioned air leaks in his book a number of times, and said the air pressure was rising in the boat.

Regardless of the cause, HA-19 would not stay on course without continuous visual sightings by Sakamaki, and he could not risk running with his periscope exposed. He had to rely on periodic sightings and adjustments to his course to inch closer to Pearl Harbor.

Because the boat had so many problems from the instant she was launched, Sakamaki and his crewman hardly had a moment to think straight for the first several hours. Once things settled down for them, they discovered to their horror that the sun had come up! There was no way to enter the harbor under cover of darkness. Emotionally, both men were drained by the time the air attack began, but they kept trying to enter the channel.

In the process, they ran aground several times (another event that is misunderstood by many). Hitting the coral reef bent the metal guards that protected the ends of the torpedo tubes, which would have prevented Sakamaki from launching his torpedoes. However, he had no way of knowing this. Sakamaki could not see the torpedo guards from inside the boat.



Navy Historical Center photograph NH-91334

The real problem with Sakamaki's torpedoes is explained by the SUBRON 4 salvage report, written several weeks after Sakamaki's boat was captured and examined. The safety mechanisms on the torpedo launching valves had never been removed, something that Sakamaki's crewman would normally have done shortly after launching. But they were so busy trying to stay alive and keep the boat from sinking for the first hour or two after launching that they simply forgot to remove the safety bolts. They certainly had external damage that prevented them from launching the torpedoes, but Sakamaki did not know that until after he was captured.

As a matter of interest, the SUBRON 4 report on Midget C noted that when the gyrocompass was removed from the boat and set up on a work bench for testing at the submarine base, it worked perfectly. I suspect that means the original problem was a simple loose electrical connection that was properly tightened when the gyro was removed and reassembled at the sub base.

The boat going off course by 90 degrees, either as a result of a leak in the air piping to the rudder control pistons or a mechanical misalignment, would explain the mysterious sound contact that the USCGC Tiger had out near Barbers Point at about 0720 on the morning of December 7.

To explain that, remember what Sakamaki wrote in his book about the night of December 7. After trying to enter Pearl Harbor all day, his boat was on the surface several miles south of Diamond Head. Sakamaki decided to call it quits and head east towards the Lanai Island rendezvous, so he set the course (i.e., he tied the ships' wheel in place) and then fell asleep. He awoke many hours later, with morning coming on, and found that he was on the eastern side of Oahu heading north. From his original course, that meant the boat had turned to port (i.e., left).

Let's assume that his boat had been turning 90 degrees off course all day to the left, or to port. From his launching position about 10 miles southwest of Pearl, he would have continually headed for Barbers Point as the boat drifted to port. Since he said it took about an hour to correct the trim problem, it was at least 0430 before he and his crewman got the HA-19 underway for Pearl Harbor.

In the 3 hours between his getting underway and the Tiger making her sound contact, Sakamaki's boat was continually turning northwest towards Barbers Point, and he was trying desperately to "walk" her in to the channel entrance buoys to the east. That explains why the Tiger's contact was so far west of Pearl, and also why the submarine Tiger picked up was running so close to the reef. It kept turning north into the reef as Sakamaki tried to make it go east. Tiger followed the contact for 10 or 15 minutes before losing it completely in the noise of the breakers along the reef, still several miles away from the channel entrance buoys.

All in all, Sakamaki was lucky by our standards in that he survived where no other midget submariners did. By his standards, however, he failed miserably and wanted only to be shot. It took several years for Sakamaki to accept that he had in fact been lucky to survive.

Edited by Ken Hackler on --

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Ken Hackler
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Ken Hackler Search for posts by this member.
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PostIcon Posted on: Aug. 12 2002,12:09 Skip to the previous post in this topic.  Ignore posts   QUOTE

In discussing the midget submarines with Tracy White recently, I realized that perhaps a little more explanation may be needed concerning their internal systems.

One of the things that came out in the weeks following Sakamaki's capture was that almost 15% of the total number of battery cells had been removed (from forward bank of batteries) to make room in the midgets for additional air cylinders. This was done just before they left for the Pearl Harbor attack.

Of course, those who have followed Midget C know that Sakamaki had problems with his trim immediately upon launching. Some have (in the past) suggested that the boat was too heavy or that she was sinking. In reality, she was too light and Sakamaki had to add water to the forward trim tank. The boat was light in the forward end because that's where the batteries had been removed. I mentioned the lead weights (called "pigs") in the previous post. Those were installed in the forward battery room and torpedo room to offset the weight of the removed batteries. Check the SUBRON 4 salvage report and you'll find that the weight of the lead pigs is very close (but not exactly) to the weight of the removed battery cells and associated mounting hardware and wiring.

One final item, that may mean absolutely nothing, is that the new air cylinders were installed not long before they left Japan for the Pearl Harbor attack. I find it interesting that one of the last things worked on was the air system, and Sakamaki apparently had problems with the system. That may not have been the cause of his air leak in the steering system, but it is interesting.

Edited by Ken Hackler on --

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1 replies since Jul. 28 2002,11:14 < Next Oldest | Next Newest >

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