Medzell, your tactic is for map contacts off, the clip is made for those with map contact on. I agree is a bit too much drawing, you should be able to set all the data you need from any angle and with more speed. When you are about to hit a convoy, there is really not much time to draw and all that, speed and precision is everything.
But speaking about manual targeting... is there any way to target without the damn "lock/space" button? I mean, is there any way to fire from under water, with the scope on minimum? I know where my target is, I know his speed, direction and all I need.. but the game dont let me fire