how do you find out the range to the target with out asking your WO?

via hydrophone or using stadimeter (periscope). although it is not very reliable (at least for me).

But the hydrophone shouldn't give you the exact range too. It should give you only the bearing and very approximate range, like 'close', 'very close', 'far away'.

If you play with no map contact update - which is the topic - the hydrophone doesn't give you any precise range. Reports from sonar only state long, medium or short range.

thats correct sir but if you use the hydrophone properly, it can give you pretty accurate range to target. see Dantenocs and Greyriders posts on this topic.

For me, "only" stating long, medium and short range is a great help.

Actually, if you use the hydrophone properly, you can acquire pretty accurate range to target. If you dont want the Watch Officer assistance, then I think the hydrophone is the most reliable way to fix the contact speed, bearing and distance and works (often) even at long distance. see Dantenocs and Greyriders posts on this topic.

IMHO, the main problem is that there are only a few people manning the hydrophone themselves, counting the RPM, estimating range by comparing the propeler sound to the hydrophone ambiance background... it is just too complicated or time consumpting for most kaluens so they just prefer to use the SO assistance - those black lines that are not real for me.

On the other side (as I already mentioned somewhere else) since TGW the original propeler sounds have been replaced by other sounds and now, there is no chart you could use for determining speed via RPM. Pitty