Found a large convoy but...

[Pisces]

AN76, that is almost inside Der Kanal. I'd say trail the convoy at the extreme of visual range, until you have at least 150 meters below you. You could have a look at an empty mission editor map to see where the North Sea is deep(er). Iirc the game map doesn't show this as well. I guess you're way to close to Lowestoft at the moment. Find out where the DDs are in relation to the convoy while underway. It's best to do this at night.