139) “Not only is the disappearance of ship’s hulls explained by the Law of Perspective on flat surfaces, it is proven undeniably true with the aid of a good telescope. If you watch a ship sailing away into the horizon with the naked eye until its hull has completely disappeared from view under the supposed “curvature of the Earth,” then look through a telescope, you will notice the entire ship quickly zooms back into view, hull and all, proving that the disappearance was caused by the Law of Perspective, not by a wall of curved water! This also proves that the horizon is simply the vanishing line of perspective from your point of view, NOT the alleged “curvature” of Earth.”

This is just not true: see the video mentioned in point 138: here it is again:

There’s no way a vanishing point could make the lower part of a ship vanish first, (as it does) since it is simple the reduction in apparent size caused by the narrowing of the angle of view to each edge.

Obviously, that reduction of size operates equally in each direction, not form the bottom up.

(By the way, only flat-earthers talk about a “law of perspective” as opposed to the straightforward effect of perspective.)

Likewise, using a telescope will not make the part of the hull hidden below the horizon reappear. At most, it might help to cut through some haze .

Another by-the-way on the topic of horizons; in point 143, Mr Dubay makes a big, big blunder! He says “since the Sun is NOT 93 million miles away but rather just a few thousand and shining down like a spotlight, once it has moved significantly far enough away from your location it becomes invisible beyond the horizon and daylight slowly fades until it completely disappears.”

Sorry, the sun goes behind what? The horizon? Really? And what is the horizon on a flat disk? There would be nothing for the sun to go behind, over the surface of a disk. And certainly not so that it could be seen from one part of the disk, but not another. How could that work?

The very idea of a horizon assumes the reality – that the Earth is a globe, and things can disappear over the curve. What an admission ;-)



This discussion shows some more examples , and claers up some misunderstandings about "perspective":
https://www.metabunk.org/help-with-a-debate-about-curvature-and-distance-calculations.t8656/#post-205400