It's Bratwurst! Do not ever dare to misspell this holy german meal again!
J/k of course. Well, I think you did everything right. Since the juicy tankers sometimes sail in the middle of the convoy I often get too close to the ships on the sides. Suddenly there are 10+ lightfingers pointed on the boat and a lot of shelling flying around. I think 1 - 1,5 km is the best distance.