So far on this thread I've seen two presented from the globe earth side, one of the windmill blades and the other of a ship disappearing. In neither one was any zoomig in attempted after the object left from view. There was no indication of how far the oject was. Even cameras that can zoom have limits. Even if you had infinite zoom capabilities, at some point the atmosphere between you and the object would obscure it, regardless of the magnification. That's why recording the actual numbers is crucial.
If an object disappears because simply because of perspective, it will get increasingly smaller until it can't be seen by your eye or resolved by the visual instrument (binoculars, telescope etc.). Just like in the video of the oil rigs that are "brought back" by the amazing zooming capabilities of a Nikon P9000.
In the linked ship video, and in all other "object disappearing on the horizon" videos, they disappear from bottom up. Something is obstructing the view to that lower part of the object, while the upper part is still easily and clearly visible. How could the terrain or the water obstruct the view to an object on a flat disc, all the time, everywhere?
Strangely, the globers argue "refraction" for every single "see too far" video but then fail to consider that refraction might have influeced the two or three pictures that they have.
There may be instances where the "8 inches per square mile" doesn't fit completely due to refraction and what not. So you may be able to see
too far, but you can never see
far enough for the Earth to actually be flat. Nobody ever sees Mt. Everest from e.g. the Americas with a telescope or with the bare eye. Why is that?
Finally, when PBS/Discover tried to put together a video to demonstrate this phenomenon of something disappearing over the horizon, the video was clearly faked, as exposed here. Why fake it? It should have been easy to come up with a real video demonstrating the same thing.
[youtube link]
Well I've got to agree with you, this video has to be faked, it's ridiculous. I'm not sure how or why they did this, they seemed to have used the same video clip twice. But - by the way - the helicopter still did disappear and reappear on the horizon

But let's not focus on a video that's clearly been tampered with.