/2/ It's a myth that sonar pinging harms divers. I have been in the water very close to pinging sonar, it's just a loud ringing "PING" sound. No big deal. In Beirut we had any destroyers in the area ping, but only to frighten the potential swimmers. (We spread false rumors that it would sterilize divers.) We also tossed 2.5# socks of C-4 off our fast boats every few minutes all through the ship anchorage, again, the odds of hitting a diver were negligible, it was mostly a scare tactic.