You were 75km away from Pearl, US destroyers came out pf Pearl Harbor and were still able to find you from that distance? Something doesn't sound right. I think those DDs were probably a lot closer than you think. Always check your sonar periodically during an attack, just to make sure nobody is sneaking up on you from behind. Sorry, I never played the U-Boat campaigns but, how the heck did you make it all the way out to Pearl in a U-Boat?