Not OP but I can reply about earth curvature calculations.
You can do a search and find earth curvature calculators such as these.
https://www.omnicalculator.com/physics/earth-curvature
For an example from my personal experience I can see a city thats 20-30 miles away. Laying down on the beach doesn't really change how much I can see so I'm not gonna bother with the eyesight level differences that the second calculator has, I'm gonna use the first.
So if I plug a number into this calculator, it spits out the amount an object should be hidden... From the bottom up according to the ball model.
20 miles: 0.05052 miles = 266.75 feet
30 miles: 0.11367 miles = 600.19 feet
So that means I shouldn't be able to see the bottom 266 feet of whatever is 20 miles away. I'm not sure exactly where they're getting that, as I can still see all of the beach on that opposing shore. Nothing at all looks like its hidden.
Not OP but I can reply about earth curvature calculations.
You can do a search and find earth curvature calculators such as these.
https://www.omnicalculator.com/physics/earth-curvature
For an example from my personal experience I can see a city thats 20-30 miles away. Laying down on the beach doesn't really change how much I can see so I' not gonna bother with the eyesight level differences that the second calculator has, I'm gonna use the first.
So if I plug a number into this calculator, it spits out the amount an object should be hidden... From the bottom up according to the ball model.
20 miles: 0.05052 miles = 266.75 feet
30 miles: 0.11367 miles = 600.19 feet
So that means I shouldn't be able to see the bottom 266 feet of whatever is 20 miles away. I'm not sure exactly where they're getting that, as I can still see all of the beach on that opposing shore. Nothing at all looks like its hidden.