[SabreHawk]

Yes it is hard, and for sure was hard for the real ones. Many of them sailed around out there for weeks and never found or spotted a thing, its a big place.............the ocean is.

As has been the case in the past, I'll listen for myself with motors off and have heard ships from wayyyyy off, barely audible. This is the one thing that the SH series has done well. Simulate the hydrophone operation.

Now if while listening you do find something, listen for a few minutes and see where you have to move the pointer to follow it. Then leave the station and call up the map and a sound contact line should appear. Now place a marker right at the tip of that line, and then watch it for a bit and note where the tip goes. then once the tip has moved some distance, place another marker at the tip and then you can with the ruler draw a line between them and have a very good idea of the course the contact is on and if headed away or closing or some other direction.
Hopefully it's closing towards you. But if not, you may still be able to get to it if it's not traveling fast. Surface and set course to close the distance. Then after some time, submerge again to check on it. then repeat and eventually get close enough to get it spotted and then an attack can be planned.