[don1reed]

@ Petr:

Nice to see that you are playing @100%.

Although History tells us that the “Greatest Generation” did not use any electronic tools to determine distance (entfernung); save PPI radar, late war, Allies.

Pre-radar and later, to avoid their own radar signature from detection, US Submariners used the “High-Scope” method, where the scope was raised to full height while surfaced to see targets beyond the horizon. In fact, this “high-scope” was modeled in the original Silent Hunter. Alas, it is not used now; and, Kriegsmarine doctrine did not allow for the use of the highscope method. (Uboot Commander’s Handbook.)

What they did have, however, was their state-of-the-art optics and mathematics:

Ref: “The American Practical Navigator” a.k.a. “Bowditch” (Free copy on the web via Google) demonstrates in Table #12. Distance of the Horizon-

Distance in n.m. = 2.12 √ height of your eye asl* in meters. *asl = above sea level.
note: if using height in feet, make the constant 1.169 instead of 2.12.

Ref: “Bowditch” Table 15. Distance by Vertical Angle Measured Between Sea Horizon and Top of Object Beyond Sea Horizon-

They used their sextant to measure these small fractions of angles; and apply corrections due to refraction etc.; however, this brings us up to date of how we, as players can estimate long distance target ranges and thereby, plot their courses.

When a target ship is hull-down, you can estimate it’s masthead height (MHH) as 100 feet or 30.48 m...apply the Distance of the Horizon formula, above, for the target’s perspective, add the results to your own distance to the horizon and you will have your answer for plotting.

Cheers,