In past, I used to attack escorted convoy during daylight within or up to 1000m submerge to nearest ships using T2, with one torpedoes per ship, until I learned to preferably wait until dark using T1 during surface attack, two torpedoes per ship, from around 6000-10000m away, then I have plenty time and room to flank away on surface before torpedoes hit targets. The escorts tend to sniff in wrong spots, usually 1000-3000m away from convoy which I am way away from. So I am nibbling two ships out of convoy at a time, then intercept the same convoy again to sink another two. That way I won't get detected and better chance to survive. But later war years when radar comes in, I have to intercept convoy in ahead submerge, once I fire torpedoes from 5000-10000m depending on weather, I crash dive away from convoy. It's interesting how much time I have played in GWX, my playing style have changed compare to stock. I am much more comfortable attacking furthest away rather than going into the middle of convoy unless there is nasty storm and water is deep enough.
