Framing Question

Should I used marine grade plywood as my frames when building with divinycell, or can I get away with something a little cheeper? Seeing how they are going to be removed and replaced after I do my layups with fiberglass? Also what is some methods used for setting up my frames to keep them inline? (I have seen some people use an I-Beam)

 

You can use any plywood. I set a frame around the middle plumb and square. Then use spacers to set the others.

 

A 2x ladder frame works well. Space the joist to coincide with the mold spacing, keeping in mind to go forward of the spacing in the aft sections and aft in the foraward sections. Get the midsection perfectly plumb and square then measure from there.