In TWOS the 3-circle method of the stock game is gone. The procedure for Auto-TDC is now pathetically easy:
You lock the target with space bar, you unlock again with space bar, you move the mouse to fine-tune the ship section you want to hit, then you fire...
That's it, all the job will be done by the Torpedo Data Computer for a perfect hit
However for the Auto-TDC to work like that, you must deactivate the Manual TDC in the OFEV, and also in the in-game Options.