First campaign in vanilla SHIII. Decided to raid Scarpa flow for the lulz. Crept neatly in ala Prien. Avoided the escorts. Found the harbour completely bloody empty. Tried to sneak out. Broached the surface. ASW Trawler. I think to myself "I'm a cunning sort. I'll rest on the seabed run silent, run deep style. Sonar will be scrambled by the seabed." Short time and precision dept charge run later and the remains of my Type II are scattered over the seafloor.
Only later via this forum did I discover that in SHIII allied sonar ignores the seafloor. I was the ideal target. I was even so newbie I hadn't changed to silent running...