Quote Originally Posted by Bill Greenwood View Post
Ron, I dont think there is firm evidence that one of the mini subs ever got inside Pearl Harbor, through the anti sub nets, or fired a torpedo there.
The Ward sighted, fired on and sank a mini sub just outside the harbor entrance, 6:30 am BEFORE the air attack, began.. A few years back that sub was found, but I dont recall if it had a torpedo still on board or not, same as one which ran aground elsewhere.
I saw a program on the search for this mini sub about 2000, I think. One of the surviving Ward crewmen said then that the search was too far out to sea, should be a few miles and that they had shelled and hit the conning tower. Experts doubted him, but when found the sub was where he said with a hole right through the tower. I think a arial torpedo can be pretty large too.
Certainly, there's no hard evidence that any of the subs made it into the harbor. Even the perceived "bigger" hit could have been an aerial torpedo with a secondary explosion from munitions on Oklahoma.

I had thought the midget subs carried the famous Long Lance torpedo, but they had reduced-size version that was 18 inches in diameter vs. the 24 inches of the Long Lance. Found a cool site that presents the differences between Japanese submarine, ship, and aircraft torpedoes:

http://www.combinedfleet.com/torps.htm

The type 97 used on the midget subs had about ~75% more explosive than the Type 91 Mod 2s carried by the Kates at Pearl. Same diameter, though, so there were probably a lot of similarities beyond the extra explosive in the midget-sub torpedo. Total weight of the mini-sub torpedoes wasn't that much more than the aircraft ones.

One of the aspects of the Pearl Harbor attack is that there were many "Experts" who claimed an aerial torpedo attack would be impossible....that the floor of the bay was too shallow, and the torpedoes would hit the bottom before they could level out and find their running depth. However, a year earlier, the British Royal Navy had attacked the Italian Navy anchorage in Taranto Bay with good results. One thing I'd read is that the Japanese had installed breakaway fins on their torpedoes to reduce their post-impact dives.

Ron Wanttaja