Miaow boys!
Anyway, you who need to know exact ranges are not real men

. I've actually stopped using the recognition manual at all, and guesstimate the mast height and ship length from observation only.
You can obtain perfectly accurate targeting data with inaccurate range measurements.
If for any reason you strongly doubt the accuracy of your range estimate, just point your boat in such a direction that the gyro angle is roughly 0. This will render the range estimate unimportant.
Then fire a spread, longitudinally (Dick O'kane) or fan shot
And then quit complaining:p