I built my Guillemot 18 with double 6 oz. on the bottom, sheer-to-sheer, 6 oz. everywhere else, and an extra layer of 6 oz. inside the cockpit bottom. I also have 1' x 3' 15 oz. biaxial s-glass reinforcements inside the stems. I don't regret any of it, and the boat is still 47 lbs.

I've got scratches and dings a-plenty, and don't worry much about them. I actually like the extra 6 oz. on the sides, since I got some major dings peeling out of an eddy in Deception Pass. When the current got pulled downstream, I was a little too close to the rocks forming the eddy, and the stern spun around and WHACKed them hard. I lost the first layer of 6 oz. in those spots, but no water got to the wood. They won't re-wet out perfectly, but I know the hull is still strong.

I knew when building this thing that double 6 oz. on the inside would be stronger for major impact damage, but I'm not realistically going to see much of that. Scratches and dings are a lot more likely. I like Nick's and Lee's suggestions of 6 oz. over 4 oz...like Nick said, ply is denser than cedar, so 4 oz. everywhere would probably be fine with a 6 oz. football.

And some lakes can be really hard on boats, too!! (or maybe it's just the paddler!!)

Shawn

: This Sat. I found myself caught on top of a smooth rock pile with the waves
: going out from under me etc. 1 1/2ft seas. basically calm conditions. I
: put some nice deep scratches into the bottom glass that won't re-wet out.

: Question or concern: I'm building a Sea Spirit S & G hybred and was going
: to try to use 4 oz. cloth throughout to make it light. After this Sat. I
: reafermed my belief in 6 oz. with an added 6 oz. football on the botom. I
: know many use 4 oz. and I'm convinced that it's a fals sense of security
: or for lake paddling only. If I had 4 oz. on my Outer Island, I would have
: been into the wood. I think it's cool to carry a super light boat on your
: shoulder down to the beach but to take a pounding on a rock, I just don't
: think 1 layer of 4 oz. will protect the hull at all.

: I scratched up mine good and remember, - calm conditions, no real big waves -
: just laying on some smooth rocks and having to lift the hull with my hands
: to free myself.