Bad enough to warrant constant pipes, a chit that requires multiple signatures from multiple people in the chain of command with safety checks ontop of safety checks, notifying adjacent ships and port services if required, and hauling up that good old flag alpha. Only then can divers enter the water. If you’re in open ocean you’re making constant radio calls to notify any adjacent shipping so they stay well clear and not use sonar or underwater transmitters

The navy tends to learn lessons about safety the hard way. So these precautions come on the shoulders of countless sailors injured at work due to the lax safety standards of the time. The fact the PLA-N (who have similar safety precautions, as they have done diving ops at garden island and I had to sign off on it as the ports services rep (fuck knows what I was signing, it was in Chinese)) came over and deliberately used sonar was directly passive aggressive action and could have easily killed some of our sailors and they would have just said it was an accident or must have been an accidental transmission from the Australian ship.