Hydrophone range
 

Two questions...

What is the range you (the player) can hear ships on hydrophone?

And what is Benno’s range to hear them?

I’m use to sh3 sensors. Still getting use to sh5.

Depends on ship's speed and type. I hear warships within 20 km if they run at 15 knots. For cargo ships at lower speed in bad weather I suspect you will hear them once they are at less than 8 km, not quite sure about.
Convoys can be heared at much higher ranges if more than 5 ships are in a group.
You are always better than your sonar man, so always go to the station if you suspect something is nearby. Sonar man will also not easily give you a range estimate unless enemy is very close, you must find out yourself, e.g. with the 4-Bearing method.