I'm not saying you're wrong, but I've not read any reports of an unexploded torpedo punching through the hull. Must have happened sometimes I suppose.

More common in the reading I've done is the air flask rupturing. The dud torpedo broke apart as the result of the impact, and it would appear like a low order detonation, but was just the torpedo rupturing. One of the V-boats for instance had this happen at Midway when she fired on a carrier, Kaga? The flask was then used as a life preserver by the carrier's crew, meaning this attack did more to save the Japanese than to harm them.

I've been reading through the Japanese convoy log Donner sent me, and surprisingly there were indeed flooding incidents caused by dud torpedoes. So far I've encountered only one that actually sank from that. Of course one is more than enough to get my attention.

At the other extreme I've found one incident in which a perfectly normal 9,815-ton cargo ship took six torpedoes and five hours to sink!

That's the one. Couldn't remember the name so I left it out.:)

Do you guys know of any specifics on attacks where an unexploded torpedo sank a ship? Which sub was involved, which target? Or date maybe?

I have that info at home. I'll try to post it tomorrow.

From the book Submarine Diary by C. Mendenhall.

"..in late 1943 Hallibut sank a ship simply because wo dud torpedoes punched 21"inch holes in the side of a freighter.."

I am currently reading above book and when reading this about Hallibut I used that info the check the book "US Submarine Attacks During WWII" by John D. Alden. But unfortunately it did not any ships sunk in 1943 by Hallibut with duds :-(

I'm temporarily unable to access any of my files, but I definitely did set aside the info from one ship that sank from a dud and two more who barely escaped that fate.

Sometime in the future I will post it. It's real.

How did I start this thread? :)

FWIW, after those posts I've looked into it a little further, and there were several instances where JANAC gave credit for small freighters sunk that the sub did not claim. One of Tang's patrols featured this occurring, among some others.

It's very possible, even likely I suppose, that many of these unclaimed confirmed sinkings were the result of unexploded torpedos punching holes in a ship.

Damage caused by dud torpedoes
 

I'm trying to confirm an account of damage to the Tofuku Maru by a dud torpedo that happened between November 8-18, 1942 (more or less). My dad was on the ship as a POW and he told me that they were travelling in blackout when somewhere around French Indochina, he said they were hit by a torpedo. Luckily it was a dud torpedo, but there was some damage and the ship went to Takao, Taiwan for repairs. So I'm trying to figure out which sub hit his ship. I think it was the U.S.S. Grenadier, but have been having trouble finding out more about the Tofuku Maru and the Grenadier.

I'm working on a documentary about my dad and about the POW experience. I looked in Greg Michno's book, "Death on the Hellships: Prisoners at Sea in the Pacific War" (Naval Institute Press, 2001), but it doesn't list the Tofuku Maru. I found a link from the Berkeley archives that mentions the ship, but not the ship that fired a torpedo at it. Any help would be appreciated.

I don't play sims right yet, but am really impressed with the forums here. Your research is thorough and interesting. Playing might help me with my research and with understanding a bit more my dad's wartime experience.

This is driving me crazy! I have that info set aside on my own computer, but I can't get to it and probably won't be able to for several weeks. Sorry I couldn't be more help; I'm trying.

Tree, as far as I know it was Gurnard that was credited with sinking Tofuku Maru. Must have been a different attack than the one your father experienced. This attack would have occurred around Christmas, 1943.

Ahh, the attack you speak of was in 1942. I'll see what I can dig up.

Thanks, I'm still looking into which submarine...prob not the Grenadier
 

I got excited by the Grenadier because:

http://en.wikipedia.org/wiki/USS_Grenadier_(SS-210)

"The Malay Barrier was the site of Grenadier’s fourth war patrol from 13 October to 10 December. After laying a minefield off Haiphong, Indochina, the submarine made an unsuccessful attack on a large freighter. During the severe depth charging which followed, sea water seeped into the batteries..."

However, I am talking with my dad and he says that he does not remember hearing any depth charging. So even though he was on a freighter, that attack wasn't the right one. He remembers choppy seas that evening...so we keep on looking.