Actually, from what i've read, it was a lot more common than that... but the 4 quoted are the most famous incidents... it happened on the order of maybe 1% of firings, i am guessing from what i've read.ORIGINAL: Shark7
ORIGINAL: Charbroiled
ORIGINAL: Shark7
That indicates malfunction then. I would still assume that even so the ratio was very low....so still not impossible, but improbable.
The Tang (Dick O'Kane's boat) and the Tullibee were both sunk from a circular torpedo run. The Taotog and the Whale both had torpedo malfunctions causing a circular run, but both boats were able to "go deep" to escape.
Yes, I'm not saying it couldn't happen. I say improbable because of the fact that you cite 4 instances of circular runs out of how many thousands of torpedoes fired?
I say improbable because there is such a low chance of it happening. It can happen, and it if happens to you it is 100% bad, but in the overall picture you can reliably fire a straight running torpedo 99%+ of the time and it will run straight...or at least not in a complete circle.
EDIT: Usually, since the sub was moving, it wasn't around for the return trip of the torpedo, and just made for a lot of nervous/alarmed submariners.