BTW, many of these flat earthers claim some sort of biblical allegiance as part of their thinking. I just want to say [and I am not trying to turn this thread religious or get myself banned or start a flight] that the Bible actually hints at a spherical earth in Isaiah 40:22. Isaiah is believed by many to have been written around 750 BCE. In that verse, Isaiah wrote: "It is he who sits above the circle of the earth, ..." The Hebrew word chwg, translated here as circle, can also mean vault. For instance, in Job it refers to the "vault of the heavens." Most likely Isaiah meant that from the vault of the heavens, from God's point of view, the earth appears as a circle.
Some have tried to make the word mean globe, but that's a stretch, since there is a different Hebrew word for ball, which would have been closer. But in any case, the sphericity of the earth may well have been hinted at here. Regardless, Hebrew is a very picturesque eastern language, full of allegory and metaphor. It is designed to give word images, as opposed to bullet-point facts, which would be more the style of the later Greeks. Just read the Psalms to see God referred to as a rock, a strong tower, a refuge, an eagle, and many other things that are not meant to be taken literally.
In summary, the Bible makes no claim as to the shape or size of the earth, and those who think it does are guilty of misunderstanding the nature of poetry.