Timing a target for 3 minutes 15 seconds on the plot gives target course (and thus angle on bow), speed and range. So everything you need for manual firing. The trouble is it's a computer game thing. In real life in this time period it was not generally possible to get a sufficiently accurate range for this approach to work.
The real attack methods were designed to avoid accurate measurements of range. Take a look at Tonci87's series on "U-tube"
.