I've had bad experiences with point and shoot if I don't set AOB to 0. For some reason, even though speed is set to 0, the torpedoes tend to veer off left or right. Like Rockin suggested, set to 0 to be sure.
Also, if you can get a rough range estimate (perhaps simple measure on the map), use it. It may not make (much) difference, but the more accurate the data, the more accurate the shot.