It is too technical for me but I just thought of it as a option for other convoys that are not wolfpacked.
Maybe its a no no or infact there is a easier method with similar results is right under our noses. I just thought I would throw an idea in.
I have 0% experience of editing convoys etc so I will leave that to the pro's. What I do know is that a alert DD is far harder to slip past than a docile DD.
Just reading your thread and the idea of subs with no weapons and low hitpoints would probably produce the same result
