So I took a little day trip over to empire beach (next to sleeping bear dunes) on the west coast of Michigan. It's flat. I can see the sand of the beach of north manitou from empire beach it should be about 42 ft. under the horizon. That is concrete fact that the math they gave us is wrong. I also took a level and lined up from manitou all the way to the opposite shore about 40 mi away from the island... You guessed it, flat and level the whole way accross. There should be a curve of almost 1000 ft!!! Argument over for me folks. Just wow. I've now seen proof in real life.