Get out in front of the convoy.. submerge to max depth, silent running and as the escorts pass over you, start surfacing. Use the hydrophone to position yourself between the ships... Get you know your ship engine noise signatures, and pick out the 'big one'.. usually in the middle and at the back.
If the sea conditions are rough, sky is pitch black and no moon - surface and switch over to diesel, otherwise stay at scope depth. If on the surface pick a target a few lanes down - you don't want to 'illuminate' yourself.
After firing your torps get the hell outa there at +- 160-200 bearing of convoy course.. and again dive to max depth if necessary. Don't max your speed as sea spray, or engine noise turns you into a 'honey pot for the bees'.
