I think this is a game bug and has never worked
I would like my sound man to shout out "We have a sound contact" when the hydro station finds one.
So far only the watch cew will do this "Task force sighted" etc
The hydro man will call out bearing if you ask him to report and if you are in visual range to target "warship closing"etc.
I think a huge improvement would come if the soundman shouts when hydro is first picked up, way before the watchcrew see them.
This would also them make real nav a lot better as just now you get no warning unless sighted