Hi Brian,

I wish there was a standard way to draw diagrams on the net. I'm not
quite sure if I've understood correctly. Do you mean that the first set
of ribs would be mainly vertical (for a "conventional bathtub", they
would look like U's), and the second set would be longitudinal? ie, a
see-through grid of ribs. If so, would you recommend attaching a
sheathing of thin ply before applying the glass skin?

Also, by 2 inches, do you mean the width of the ply strips?

Sorry if I'm missing the obvious, I haven't yet learned much about boat
building, and probably don't see some of the things that are clear to
others.