I was told that a person six feet tall, eyes slightly lower of course, can see four and a half miles to the horizon.
I live at Bridlington and walk to the beach every morning with my Springer (dog) If the shipping is well out, although I can see it from the promenade, most of the ships are gone when I get down on the beach, which I would think is about twenty feet lower. I am referring to hull and superstructure.
When I was learning marine navigation, there was a question asking why the light house set back from the cliff edge was visible on the outward journey but not visible on the return trip six hours later, even though we were the same distance out from the shore.
Any one not know why? PM me for the answer,