Naval stadimeters weren't invented until the 1890s, but you can create a simple graticule on a post it note which you can simply stick to the side of your screen with precalculated ranges vs. masthead height in degrees.
To get there, the stadimeter formula is obtained by high school math:
(1) Divide the masthead height (about 120 ft for smaller brigs, cutters, about 200 ft for first rate) by the tangent of the angle (1 - 10 degrees) from the visual horizon to the top of the mast...
(2) This will yield you a top of mast range table, like this:
Brigs/Cutters 1st Rates
Top of Mast 120 FT 200 FT
Range to ship from horizon to top of mast at:
Brigs/Cutters 1st Rates
- 10 degrees = 225 yds 400 yds
- 5 degrees = 400 yds 750 yds
- 4 degrees = 500 yds 950 yds
- 3 degrees = 750 yds 1300 yds
- 2 degrees = 1100 yds 1900 yds
- 1 degree = 3300 yds 3900 yds
- 0 degree = HORIZON
The next trick is visually guestimating the height of 1 through about 10 degrees on YOUR display... a little harder, but not too..
I found an excel spreadsheet visual calculator through some guy at the Univ. of Toronto (link is www.psych.utoronto.ca/Fusers/barense/links/ACLab_Visual_Angle_Calculator.xls ),
that allows you to simply plug in your display size (H vs. W) and resolution (# x # pixels), which will help you convert pixels to degrees, then inches (or millimeters) and then create a little
post it note graticule with the ranges and tick marks for brigs and 1st rates on the side of your screen at the general (unheeled over) horizon.
Hope this helps someone out there - I know it's probably horribly crude to the experts, and does not take into account the deck height of the viewing platform (your ship) but I had fun doing it, and it seems to work ok so far as a simple aid.
BTW, I didn't calculate any further in depth, as I thought the max range of most of these guns is about 2,000 yds, and max effective for a 12 or 24 pounder was only about 1,200 yds, no?
Regards all, Bob W. Bristol RI, US