There is more to that story of a circling torpedo here in this link:
http://www.navsource.org/archives/08/08216e.htm
And it might very well have been the sad fate of the crew of the USS Grunion. By the looks of the extensive damage to the sub... it would seem that a bit more than a hit by the deck gun could have made this possible.
http://www.navsource.org/archives/08/0821679.jpg