Range to target with Hydro??

[sirbum69]

How would i go about getting the range to target using the Hydro...Reason im asking is because i want to try and play on realistic settings, so that another words i have no contact info on my map. Im tired of seeing the dam ship....

So when he tells me that its on bearing 300 long ways, i know how to stretch a line out on bearing 300 but i never know how far. Because he never gives a range.

Now i know if i look through the scope, then i can ask my watch officer to give me range but i would like to do it without coming up until i have too.

So, How do you all do it, until you just have to come up and when do you know to come up, if they dont give range...

Main reason im wanting to know this is because latly soon as i go down in water a line shows up, but my sonar cant find it...Then if i go up to surface a ship shows up on my map, but i cant see or lock onto it with the UZO lol....so how can it show on map if i cant even lock onto it...

I just want to start playing more realistic, just not sure how to do it...ive watched some of stonaims videos, great videos, just hes always looking through scope..