8.  “The Suez Canal connecting the Mediterranean with the Red Sea is 100 miles long without any locks making the water an uninterrupted continuation of the two seas. When constructed, the Earth’s supposed curvature was not taken into account, it was dug along a horizontal datum line 26 feet below sea-level, passing through several lakes from one sea to the other, with the datum line and water’s surface running perfectly parallel over the 100 miles.”

 So what? Of course this is exactly what we would expect from a (roughly) spherical Earth. For the whole length, the balance of gravitational and centrifugal forces are the same, so it is level to for all practical purposes.

“It's literally the instruction 'dig this deep'. Can you make an incision, 1 cm deep, in an apple?

You can? Well, therefore that apple is flat. Well done, that person.”

Thank you, Daimonie

For yet more information debunking Dubay read this, too.