I'm the random submarine guy, and man do I have some things for you.
See, when we're alone out in the water, we try to be as quiet as possible for our own good. It helps us identify what's in the water near us, minimizes false positives, and helps us stay undetected should a potential enemy show up in our patrol area.
There is only one really good tactical reason you would ever broadcast active sonar pings in the water, outside of testing - when you suspect you are not alone, but you are absolutely postive you still have the upper hand once you announce your presence to the enemy.
This sort of situation really only comes up in battle groups and task forces, because that is essentially the only way to ensure a tactical advantage. Even then, when you go active, you light up the water with a ping - an enemy may suddenly find himself with his torpedo tubes pointed directly at you, when before he wasn't even sure you were there. Most submarine commanders, in wartime, will take the shot they have right before they try to evade, and you stand a very good chance of dying.
To point this up a bit, in 8 years of service, I never once heard either of my boats go active anywhere other than for testing in undeniably friendly water.
Another thing about active sonar - you're still guessing, a bit. Yes, the guys who were listening are almost absolutely positive that the thing behind you is a whale, but now? Everything sounds like ping. You have what the computers can sort out, which might be an enemy submarine, or it might be a cruise liner through a thermocline that's making it seem to be in the wrong place. Good commanders maintain an awareness of what they think is out there, and that helps bridge the gap in the tactical picture.
So, you point the rifle, start the sight, send a broadcast, probably get shot at, and you get a range ping back... But from what, who knows? It would be hard to tell the difference between a rock and a riot shield.
Now stop for a minute, and consider your own, ordinary human hearing. You can probably readily identify the sound of a car shifting into reverse - it's pretty distinctive. Your brain can also pull apart the sounds from a three way conservation, identify who is speaking without looking, and give you an idea of how far away they are. As an electrician, on the boat, I knew when we lost an electrical bus the second after it happened because ventilation fans whine a bit when they're winding down. Electricians were already running for the engine room by the time anyone was talking on the announcement systems - we all knew that sound.
It's your world, so by all means, if echo sights are a thing, then by golly they're a thing. But if you want a more explainable, realistic technology, what these guys need is parabolic microphones, silencers, and lots and lots of patience.