Ok made i quick test with escorted convoy, and running at 1024 TC, game dropped to 1 for the first DD spotted at ... 14 KM!
Can't do better, and it seems fine to me
BUT the destroyers seemed to spot me around 11Km. It's not that accurate you are right.
I think i will decrease a bit the escorts spotting distance, so player will have more time to plan the approach.
Keep around, i'll adjust this very soon
