Yeah... zig zagging is a pain, I have found that for myself when a unit is doing this I use a larger spread on the torps and when he is very close to being on the original AOB when I took my readings for the TDC I fire away. It has worked a few times and failed a few times... I have since stopped wasting my torps on zig zagging ships and assuming they are unescorted just deck gun 'em
