I wasn’t a submariner (surface warfare/amphibious ops mostly) but work with and are friends with a bunch of submariners.
Funny you should mention sail boats, a sonar friend described how he got driven nuts trying to figure out a seemingly random, intermittent transient.
Turned out to be a sail boat with a line or something getting blown against the mast occasionally in the breeze.
I remember after the USS San Francisco accident my friend grumping at all the press about their supposed failure of their sonar.
1. Underwater mountains don’t usually make noise and if they do, be else where FAST!
2. In over 15 years, the number of times he used active sonar outside of sea trials could be counted on one hand with enough fingers to flip a ‘Let’s Go Brandon’ finger.