I liked it too because I have not previously considered the ark as an engineering project. Matter of fact I have never considered the ark as much of anything except, perhaps, horse patootie.
Dunning does alright with the wood procurement problem. That would have been a real difficult logistic. As for beams, one would not use beams to span the entire breadth of the ship. You, or Noah, would use trusses or arches. Here we must presume that Noah was an accomplished structural engineer with a good command of the necessary math and he had some reliable information about strength of materials that were not developed for general use until several thousand years later. But what the hell, he had divine guidance.
The real problem he would have endured was dealing with the fastener problem. In order to assemble a structure of the sort in question, one would need a really big load of nails or bolts and nuts. But the iron age had not yet been developed. Noah would have been obliged to use trunnels. Trunnel is apparently a contraction of the words tree nails. They are simply wooden pegs that are driven into matching holes on the pieces to be joined. Old time boat builders, even after the iron age used trunnels because they did not rust or corrode. The selection of the trunnel wood is another thing. They had to be made of a particular wood whose wet expansion characteristic was greater than that of the parent wood. Trunnels would therefore have not been gopher wood. The fasteners would have been a huge problem but drilling literally millions of holes would have been a much bigger and more laborious problem. I seriously doubt that Black and Decker or Makita drills were available to him. Pitch to seal the seams would have been there in Iraq because of all that oil oozing out of the ground, that is only if the dinosaurs had been dead long enough
Building time would have been enormous for a boat of the size of the ark. There are still a few boats being built of wood. A 65 footer will take at least a year and a half to build when there are dozens of skilled boatwrights on the job. A vessel the size of the ark would need five to ten years if there was a crew of 30 to 40 craftsmen with modern tools. Poor noah would have had a pretty rough time trying to cut all that material because he did not have saws, chisels, adze, slicks, planes, etc. (an adze is a huge sideways axe like tool used in old fashioned boat building. A slick is a huge chisel like tool common in the trade) Imagine whittling all those trunnels with a sharp stone to say nothing of shaping all those boards.
Dunning needs to be hesitant about invoking engineering principles because he is quite apparently not schooled in that discipline. He is correct with the general idea however.