Oh no, such a young and promising kaleun lost. Looks like it's BdU who was stupid sending you out there too soon
Btw, did you finish the convoy attack exam in the naval academy? It will give you a few hints and ideas on how to do it correctly.
I never attack the lead escort, risk of a miss is high, and they will know my position. As a kaleun my orders are to attack merchants. Early in the war I prefer surface attacks at night, striking when the escorts are at some distance. I can outrun some escorts on the surface, like the Flower class.
In submerged attacks I position myself in front of the convoy, silent running under the lead escort, and I'm inside the convoy. After the attack I dive deep 180-200m silent running heading 180 degrees of the convoy. The escorts know I'll end up behind the convoy, and usually wait for me there. If detected I'm avoiding the DC runs as described here.
I'm on patrol 3 in U-52, a VIIB. It's June 40, and so far I find the escorts very easy to avoid