It was called a "hull survey." They were routine and much more impressive when one was conducted on one of our carriers as our ASW was way ahead of USSR.
“It was called a “hull survey.” They were routine and much more impressive when one was conducted on one of our carriers as our ASW was way ahead of USSR.”
Been there, done that. Helicopters dropping sonar bouts all around us, Limited to 400’ depth and still got under our carrier undetected. But that was 50 years ago.