Remember the USS Tang?
This happened at night, on patrol 2, in fact this was the result of the FIRST TORPEDO of patrol 2...I had a merchant lined up in the darkness and decided to give her the gifts contain within tube 1.
When the torpedo fired it banked to about 30, with the target at about 45 and heading slow this didn't concern me.
Untill a minute later.
Except the Sargo lived, and sank it's target.
I hit flank speed and fired tubes 2,3, & 4. 2 & 3 exploded prematurely, 3 exploded so close that it enshrouded the Sargo in it's spray....4 hit but ran late, before 4 even hit I was on the merchant with the deck gun determined to get something in my patrol aside from...myself.
Yes, the torpedo rudder apparently jammed hard starboard and it almost completed a perfect circle....untill it hit my Sargo class midships.
The only gameplay enhancing mod that I was using was incidently enough the 25% more powerful torpedo mod, and this was with a Mark14 torpedo.
I made it all the way back to port at flank speed, sank another ship with the deck gun, and amazingly noone died.
Also managed to get a Purple Heart incidently enough...