I think it depends on what the skin and coating are, as well as how much it gets 'glued' to the frame when the coating soaks through the fabric. Ultimately, the fabric doesn't provide much in the way of stiffness, as you want a flexible coating to keep it from cracking.

I think a traditional frame would be more flexible weather skinned or not due to the fact that relatively few components held in place as rigidly as the glued construction of a "Yost" or frame-and-stringer type. Of course, you can lash and peg a "Yost" frame together in the same manner as a traditional frame, which should be a lot more flexible than the typical glued construction.

: Am I correct in assuming that once the skin goes on the boat frame is much
: stiffer?