Calculation error
First, it does not calculate wrong. Based on the information you provide it, you get a speed estimate. Usually you'll find it's a problem with inaccurate stadimeter use that messes up the numbers.
You're actually lucky in that you could immediately look at the number and say "no way!" Most of the time you just get a plausible wrong number and the way you find out is by watching the torpedoes cruise off to the land of Oz.
Because this method is so wasteful of torpedoes and is not able to be double-checked unless you already know the answer to the question you are asking, I don't recommend using the crew estimate of speed and course unless you just don't have time to do a plot and you can't do another end around to shoot at that target.
In other words, almost never is when you should be using the crew estimate method of determining speed and course.
|