1) The article doesn't go into physical sonic wave communication, like ultrasonic I suppose. Did that ever have applications for submarine comms?
2) I always wonder whether like in the movies, submarines actually have or ever use the audible ping. Of course, it gives away one's position instantly, but does such a ping capability even exist still, on modern submarines?
Re: #2, that is active sonar, which is for useful for locating objects that are silent, e.g., rocks.[1] It also is very loud and disruptive for whales and dolphins.[2]
I was a sonar tech on a nuclear submarine 20 years ago. I don't recall hearing about any ultrasonic applications. As for the "audible ping": Yes, such a capability exists, and it is very much like the movies. It is rarely used for the reason you mentioned.
2) Yes, every tactical platform that hunts subs has an active sonar capability of some kind. (Hull mounted, towed, dipping, sonobuoys, ...) When the ambient noise floor exceeds the target sub’s noise, you need that option.
I had 2 questions perpetually on my mind:
1) The article doesn't go into physical sonic wave communication, like ultrasonic I suppose. Did that ever have applications for submarine comms?
2) I always wonder whether like in the movies, submarines actually have or ever use the audible ping. Of course, it gives away one's position instantly, but does such a ping capability even exist still, on modern submarines?