Slimy neutrals... hehe that was a good one. For my operation it depends on weather how I approach a convoy. At night with calm sea and good visibility I stay away, and collect the data of the ships for a run, until I have really precise heading, and speed data. I make my run, fire all my tubes from about 2000m, turn away reload, and see the guys ziggzagging and the escorts getting crazy.
In real bad weather I got into the convoi with visibility at 400m I cut ziggzagging though the convoy lanes and deliver the fish from the closest range possible. In fog you can see the escorts very good, because of their searchlights... running at flank between the freighters avoiding the DD´s in heavy sea and fog is real thrilling thing...
A convoy at day... well submerged of course