Thanks for the answers guys, that was really useful. I will do better next time but hey it was only my second convoy attack, i am doing all the targetting by hand and i play with GWX.
For some reason i got into my head that if the destroyer was going fast it couldn't find me with the sonar but now i realize it only applies to the hydrophone.
I'll have to try different techniques, maybe getting right in the middle of the convoy isn't the safest approach.
