Ok. Well fundamentally your are using 1/4inch or so wood strips glued together acting as a skin over a frame which gives it some shape and support. That alone would be sufficient I guess assuming you are not too heavy. However, I would argue that it won’t be that strong because in reality it’s the glass cloth and resin that really give the board its strength. In addition, varnish alone is easily damaged, for example, banging the paddle on the rails or stones/pebbles rubbing, etc, underneath while on the beach. From then on it won’t take long before the wood starts to discolour, eventually soften and rot if left too long. So if you do choose to go the route of excluding the cloth my advice would be to apply 2 or 3 coats of epoxy resin followed by a quick rub down and then several coats of varnish for UV protection. I would also foam the inside to give the deck and hull additional support and strength.
What you don’t want to do is spend a long time building a super looking board and then have it damaged or fall apart for the sake of a few extra bucks (GB £'s in my case!) - that would be devastating.
Ah, just read your other post. I didn't realise you were a carpenter. I too kayak and have built a Georgian Bay stripper. I used this method for building the SUP too because I find it easier albeit a little slower. See my build log under 'Ispiration' in the finished pics section. I don't know if you are worried about the fibreglassing element or not! If you are then don't be because it's really easy, just adds a few more $'s unfortunately but as I said earlier it's really worth it. Plenty of advice and videos on this forum and vids on Youtube etc.
Timbo, thats a bunch. I was reluctant on the glassing. But, after watching a few you tube videos on how to glass, I've found it not so hard. It seems a little time consuming and messy, but that I can handle. I'm about 170lbs and will be building a fairly light SUP so I definitely want it to be strong. Again, thanks so much for the advise. I'll be checking out your build. I'll get back to you once I see it. Great site with great members. Thanks again.