Doubts about Sonar, Radio, Radar and TAI

[Jamesphillip]

Hello there mates, skippers, captains
First I'd like to introduce myself, I am new around here, just bought the game about 1 week ago, and been playing everyday since.
So I have some questions about the game. I've already been looking for these answers around in the forums but would like some of you guys to answer as well and give your opinion.

1 - How does the hydrophone / radio work? Do you need to be using them to detect more ships more easily and often, or you can leave it alone and the radio/sound guy will find them easily as well? Since I've been doing the British Supplies mission and rarely seen a Merchant ship, leave alone a convoy, what's the best way to patrol an area? Always at surface or submerge a while? Circle around a large area or a smaller one?

2 - What is the best way to approach a warship and then evade them? I caught 3 destroyers patrolling and got behind their backs, but couldn't get the angle right without being at their backs. Anyways I managed to sink two of them and then submerged into the deep and got away. Is that the best way to leave the area? Just submerge and hope for the best?

3 - What does the orange circles, red semi-circles and black circles around enemy ships mean in TAI? I've been looking for a legend in the forums and googling it, but found nothing about it. Does black circles mean visual range? And what about the other two?

4 - I've been playing without any mods, and do not like the game to be 100% realistic, been playing at 87% realism, with external view (just for eye candy) and map contact updates, but I would like to play without map contacts, altough that can be hard and most of the mods add a whole lot of things that I don't want to add to my game, and many mods don't have a full description of the mod itself in the forums page (believe me I've been looking around the forums.) So what are the best mods for a begginer like me without adding too much realism to the game?

5 - Is there anyway to have 2 or more data in the TDC? Or it's only possible to have one target in TDC? I caught a large convoy in their backs, manage to sneak around to the middle-rear and had to shoot one by one, introducing data ship by ship after firing a torpedo, it would be much better if I could target 2 or 3 ships at once. I don't have much practice so I use Pause a lot, but I see that as cheating and I'm looking to stamp this out.

6 - What's the best/realistic range to engage a ship? 500m? 1000m? 2500m? Sometimes it happens that I can't hit a warship because they evade my torpedoes at the very last second, what can I do to avoid that?
Is it suicidal to engage 7 or 8 ships and then submerge into the deep?

7 - I've noticed that everyone in the sub doesn't react to the environment, doesn't matter if I'm being attacked, crash diving or attacking someone, everyone just seems to be standing there without doing nothing and reacting to nothing. Is there any mod that changes this?

8 - When does the radar become avaiable? It's December 1939 and still no good.

9 - Is there any way to control the rudder by clicking or setting the rudder to X degrees, instead of having to click 100 times and having to listen to "rudder 5 degrees to starboard" a zillion times as well?

Thanks for the help