The hieroglyph is pretty compelling however the big problem I see with the theory is how did they move that much water? Was that small vessel pictured really enough to saturate the sand to move the stone boat more than a few feet? How much water would have to be moved and with what apparatus? How far were the stones transported? And how are they all so near perfect and fit together nearly perfectly, better than they say could be achieved by modern man. It should also be noted that the great pyramids are quite a bit older than this particular image.
I mean really how much water does it take to saturate all the sand in the stones path? Let them demonstrate it in practice before you are taken away by this "proof".
