A question: Could a sub that was about to surface use active sonar, pinging,
to locate vessels? Well, I mean they certainly could do this, but would
that be
pretty effective even where just listening for engine/boat sounds and
looking
through the scope would not?

I realize that in an actual war-time you might not want to announce your
subs
location until you have actually surfaced. But in peace you are just about
to
surface and show the world where you are, so it's no big secret. And I
realize
that in drills you want to get as close to the real thing as possible...but
I'm sure
they don't really shoot live war-heads either. So why not a few pings to
hear
where the boats are??