Manual TDC-how do you save an attack that goes wrong?

[supposedtobeworking]

I am a manual TDC guy and I recently started playing SH3 again and last night encountered a convoy. I have been at this a while and made usual preparations to calculate an intercept position and 90AOB perpendicular shot. There was a battleship in the middle of the convoy which I had wounded from an earlier attack and that was my target and goal...I had all calculations...calculated...and they were correct. I was about 900m away from the BB undetected still, when I think at that point either became detected, or the convoy changed course. So now my target data deteriorated fast and the BB was on a new course heading away from me, but was still not too far away at around 1000m.

so my question is what do you guys do when this happens and your perfect solution becomes null, but you are in the middle of the frickin convoy?? Is this situation salvagable and if so, how do you save it? What methods can be used to calculate a quick solution when the target turns away, eliminating a 90AOB shot, from you but is still close enough to fire a torpedo with a good chance of hitting? This has to happen to alot of people and as the saying goes, the perfect plan is the flexible plan (I may have made that up...) Basically I just want to know what everyone does when this happens and how each person tries to save what was and still could be a successful hunt.