OK, Flerfies, here are two items that your lot never seem to be able to deal with:
1) Ships disappearing below the horizon. As ship sail away from you toward the horizon, they disappear from the botton upward. The hull disappears first, then the deck structures and lower masts, then the mastheads. Flerfies always claim that it's merely a matter of perspective, and that with a powerful enough telescope or binocs or whatever, you can still see the everything that's above water. This is easily shown to be untrue with pictures take with long lenses, which show that if a ship is hull-down (hull below the horizon), it doesn't matter what kind of magnifying bring-em-near you use, all you're gonna see is the part of the ship above the horizon, even though it's well above the water line, even though, being magnified, the part we can see is bigger. Those few Flerfies who've actually tried it and found it true, have invented a haze that exists only far away that rises to prevent you from seeing the hull when the vessel is "too far away" (i.e., below the visible horizon) to be seen. (Handy, that; good job it never gets any closer than that.)
then
2) Long Path RF propagation. I've actually done this. Point beam antenna toward Australia on 20 meters. Lots of interference, can't have a decent conversation. Switch to CW (Morse code, more efficient), Aussie ham suggests "long path", each of us turning our beams 180 degrees, the "wrong way" around the world. Lo and behold, clear air, good signal both ways, no problem having an extended QSO (conversation) about a mutual favorite footballer. In flat earth terms, there can be no "long path".
Never had a flerfie even attempt to explain long path, and their "explanations" of the ships dropping below te horizon are all lame excuses.