The PBS series, NOVA, broadcast a show on January 5, 2010 about the mysteries around the Japanese submarine attack on Pearl Harbor on December 7, 1941. I was able to participate in an interview with the researchers behind the work discussed on the program. While that show was generally accurate, there were some differences in emphasis and timing that did not agree with those of the original research.
Historians have recognized since 1941 that the Japanese augmented their air attack on the U.S. fleet at Pearl Harbor with a submarine attack. Some twenty submarines were deployed around the Hawaiian Islands, and five mini submarines were launched in an effort to penetrate the harbor and attack.
The public, fed by movies and a brief history lesson in school, believes that the attack on December 7 was by carrier based aircraft. This interview provides a clearer picture of that day and the actions of the Japanese mini submarines. The faux newspaper clipping above illustrates an alternative view of the days events.
Of the five mini subs that the Japanese launched, one was intercepted and sunk by the destroyer Ward well before the aerial attack began. Her reports were ignored in the early hours of December 7.
Pearl Harbor was protected by torpedo nets, but they had been withdrawn because of expected ship traffic. The nets did not extend to the bottom of the channels, and it would have been possible for the mini subs to sail underneath. If necessary, the subs were equipped with net cutting devices.
At about 8:30 a.m. local time, the USS Monaghan was sortieing in response to orders when it observed a submarine being attacked by two moored Navy ships. Monaghan proceeded at flank speed to where the sub had been seen with the intent to ram the sub. It also launched a depth charge attack. The actions of the Monaghan resulted in the sinking of that Japanese mini sub.
In 2004, a team of analysts including Mr. Peter K. Hsu, Mr. Carroll Lucas, Dr. and CAPT. Andrew Biache, USN(Ret) and CAPT. John Rodgaard, USN, published an article in the USNI Navy History magazine describing their work on a captured Japanese photo from the attack. That photo seems to show a Japanese mini sub broaching the surface, a torpedo wake and an explosion at the side of the battleship West Virginia. It also appears to show a second torpedo track aimed at the USS Oklahoma.
Until this point, there had been little reliable evidence that any Japanese mini sub had penetrated the harbor and been successful in conducting an attack. There are numerous accounts of sightings by survivors of the attack and ships reported contacts and conducting several attacks on presumed subs but concrete proof was limited.
Mr. Hsu discussed the evidence. In his expert opinion, the sub in the photo had been forced to the surface due to the cavitation and various pressure waves being generated by both the torpedo explosion as well as the air attack. Within the relatively shallow harbor, these explosions would bounce off vessels, the shore and the bottom and would be capable of lifting the mini sub to where it would surface.
The mini subs were designed to launch their two torpedoes from periscope depth. The torpedoes would have been set to run at sixteen feet.
The sub did not survive its attack but what happened to it remains a mystery. Its remains lie in a Navy dump, underwater. Photos clearly show that it was cut into pieces and the cables used to lift and tow those pieces remain attached. No record exists, however, of the capture or disposal of that submarine.
Here is some information about one of the subs that did not penetrate the harbor.
The Japanese midget submarine at Bellows Field was salvaged by a Navy crew, 1941.
A Japanese 2-man midget submarine grounded on the coral reef off Bellows Field, was commanded by Ens. Kazuo Sakamaki who swam ashore on December 8, 1941 and was captured.
The Japanese Mini submarine was 80-foot long 6-foot diameter, 46 ton displacement, battery operated with 600 hp motor. Launched from mother sub (I-24) arrived off entrance to Pearl Harbor late evening, December 6, 1941. Was grounded off Bellows Field on December 7, 1941.