Next Realism step

[Miltiades]

So I've finally made my first successful escape, and weirdly enough escaping from from destroyers and hearing depth charges going off around me seems much more fun that actually sinking merchants (Yeah I know)

But the thing is , I had the stealth meter on.
So what I wanted to know is what to look out for without the stealth meter.
First of all, using the hydrophone is a big no, no matter how fun it is, second, not sure but it seems that you can tell if the destroyers see you by the pinging sound.
Other than that once I get the manual aiming under control I am on full realism...
Except my Captain's Name