RE: Do you need to cover blue board?
In my opinion its very important to cover the foam and also to epoxy the base to the foam instead of glue for a couple of reasons.
First is waterproofing. Foam has the ability to absorb water, especially after if has been sanded on. This will eventually add weigth to the boat. Blue, yellow, and pink are denser foams than the white. White is the worst about water absorption.
Second is durability w/ a sense of security. Without any protection you would have to confine the running to strictly open water. Any floating or slightly submerged twigs or debris is gonna do some damage. Any "knicks" or "gouges" on the bottom is going to affect the performance of the boat. I laminate 1/8 doorskin on the bottom and rake for added protection. That allows me to run dry ground without any worries. I have flipped a boat on dry ground at 3/4 throttle. It rolled head over heals three times before it landed. It suffered some damege but it was minimal. The epoxy held the boat together, all that was affected was the corners that hit during the roll. Without the epoxy, I believe it would have snapped the boat into a couple of pieces.
I like to epoxy my stands to the foam then glass over that. Again for added security. Keep in mind that's what gonna keep the motor from seperating from the boat.
Just my experience from my buildings.