[Major Johnson]

Well I''ve taken the plunge. Switched to manual targeting, and have downloaded the 3 videos. I keep watching them over and over hoping it'll sind in, but I do have a few questions. During the torpedo attack using the periscope video:
1. He identifies the ship and sends that info to the TDC.
2. He takes his first stadimeter reading and sends that to the TDC.

Exactly what does that first reading send to the TDC?? Location and bearing of the target??

3. He takes a little time to set up his torpedos while wating for some time to pass so he can take is 2nd and final reading.
4. 3 minutes pass and he takes his final reading with the stadimeter again, sends the data to the TDC then activates the Position Keeper. Somehow that reading also gave him the speed and heading of the target. I saw the speed displayed, but I can't figure out where the heading of 1 degree was displayed. Can someone explain that to me??

Also in his attack map there was an overlay of a compass around the sub. Is that in the stock game or part of a mod?? If it's in the stock game, how do you activate it??

And finally, Is there a way to clear the TDC of data??
Thanks.