Hitman (at the risk of kidnapping the thread), I always thought that from a trigonometric point of view the range was irrelevant. I've read and understood your parallax post but I can't reconcile that with my current understanding. Perhaps you could tell me where I'm going wrong?
Stand by for artwork of the century:
I thought that, given the target speed and course remain constant the range is irrelevant? If you imagine the target ship in the diagram 'sliding' closer or further away (ie, if you change the range), the angles of the triangle all stay the same. Because of the sine law the ratios and angles all remain constant.
To put it into words, imagine that triangle was equilateral for argument's sake. If you move the target ship 1m further away, the torpedo has to travel 1m further and the ship has to travel 1m further - it will still hit, regardless of the range.
Because it's all to do with the internal angles of the triangle, whatever range you put in is irrelevant. All that matters is the AOB and the angle of the target. Since the latter is known (you read it off the periscope), the only two things that matter are the AOB and the speed. Armed with this knowledge, when I'm in a tight spot on SH3 I sometimes just quickly click the AOB and speed and 'snap shoot' without entering the range - and still hit (most of the time).
I know I'm looking at this mathematically rather than operationally. In real life they would of course input the range to check the target was in range at all, and secondly to calculate the angle of spread for multiple shots.
If you could point out where I'm going wrong I'd be very grateful :p