[Rockstar]

If at periscope depth send him to the attack periscope, if it’s a surface attack send him to the UZO. Once he's there click on the crosshair which will appear next to his avatar to look through the optics. Find the target, click the mouse to lock on and that will bring up the ‘TDC’ at the bottom of the screen. Now you can thumb thru ship recognition, determine it’s velocity, course, distance, flood tubes, set torpedo speeds, depth and spread.

It can be difficult to achieve and maintain target lock in heavy seas especially if you're using the manual option to maintain periscope depth. At times, so difficult that out of frustration of I've ended up surfacing the boat to use the deck gun which is just a little easier. But then they're close enough to see you too and depending on your realism settings they may just maintain course and speed, try to run away or run you over. Alot going on, target acquisition, having to keep those torpedoes greasy, air tanks filled, bilges dry, collision avoidance, sleep deprivation, watch schedule, etc etc. Good luck.

I also use the mouse scroll to back out of the optics view.