Welcome aboard Kaleun. The killing solution is simple: get close, aim the boat, lead slightly and LOS!!. As Von C. says "In war everything is simple but sometimes the simple is difficult"!?? So ve haf Math!?? I generally penetrate the convoy to 500 yards and mind the 300 yard eel arming distance as per Silent Otto K.-"one ship one eel" ie 'economy of force' for U-boots. Some skeet 'shutzen' is useful, as with pheasants. Good hunting Herr Kaleun!