The Pygmy kits usually glass only the seams on the underside of the deck, but they are plywood so strength isn't an issue there.

I would be concerned that moisture is more likely to penetrate without the glass layer. The swelling would open more cracks, letting more water in, more cracks...

Since the glass on the inside of a kayak doesn't typically get fill coats, I don't think the weight saved by skipping the glass on the inside is worth it. I'd make the wood thinner instead, about 4.5mm. I don't have experience with that wood, you could even do a test panel with 4mm.

--Kim

: Hi John
: Thanks for your fast reply. I have studied the building method and am aware
: of the function of the fiberglass and on traditionally built cedar boats
: it is proven that the fiberglass is very much needed. The only reason I
: dared asking myself the questing of ommitting is because I wondered if the
: harder and more rigid kind of wood that I am using and glueing with a good
: quality epoxy glue, might give the structure the rigidity needed.

: Arthur Jacobs