Thanks for reposting. Strange enough, the original post, the font color changed and is readable.
1. Like others have said, plot ahead and sit and wait. Try to get your boat in position so that it will be inside the convoy when it arrives. Don't wait until your target is 90 degrees to you to fire. Fire when the target is still about 20 to 30 degrees before reaching your 90 degree mark. Line up, fire, then quickly turn your periscope to fire behind you. Early war, you'll want to fire 4 mark 14 torpedoes at one target, because of the chance of duds. Later war and Mark 18s, you can fire two or three per target. Once you're through firing, crash dive, very deep and get out of there.
2. Don't bother with task forces unless you can accurately line up ahead of time. Pick one capital ship and unload on her. If you get all cruisers, then you can try two or three at once. Again after firing, go deep, and get out of there. Although difficult, a task force can be a lot of fun.
3. I think the lights are search lights.
4. I like the Gato and Balao class. I start with an S-boat and upgrade as the new boats come available to me.