Thanks.
There have been some great and helpful replies.
I started my 1st career patrol Friday night on Sept. 1, 1939 in a Type IIA.
Sank 1 small freighter in which I did a long range intercept on using the techniques I learned from this forum. Had a perfect approach once I sighted him. Unfortuneately, my 1st torpedo missed astern(ok-semi-perfect approach.

), but I got him with a second shot. Nothing else came my way and I was kinda worried about fuel state, so I didn't go swanning about looking for any more targets. I did see some possible intercepts but they were heading the wrong way.
I have to pay more attention to travel ranges at different speeds and such. I'm learning though.
So far, I'm having a blast.