If Earth Is So Big Why Do Boats Disappear?

The earth is flat, you you believe? Earth is a level, non-rotating, topographical plane. It's not moving, it has hills and valleys, but it's level. Water tells us that it's level. We use water as a level, right? If the earth was a ball, it would have curvature. All balls have curvature, would you agree with that? Yes. The curvature on a basketball is different than the curvature on a yoga ball. It's more curvature over less of a distance, right? So, if we have the radius of the earth, which is a line from the center to the surface, we can figure out what the curvature is. Now, we're told, Bill Nye the Science Guy with the bow tie, would say, the earth is so big that we're just microbes on a basketball and it would look flat to us, right? That's what we're told. But then they want us in the next breath to believe that we can see boats disappear from the bottom up over the physical horizon.