It's an amazing job by Joe and OLC, I'm proud of having been able to collaborate with them
One precision to the user manual: For fixed line speed measuring with the U-jagd chrono, the manual tells you to reduce speed as much as possible. That's correct, but precision is improved even more if you set your heading to the enemy ship whose speed you are measuring. That will ensure your "fixed wire" (The vertical line of the scope crosshair) moves less when compared to the target, and doesn't influence the result.
Happy hunting everyone