Hey don,

I suppose if one was really obsessing about the data, it would be important to make a few panels to average variations in wood,lay-up,etc. I think one has to be careful though in making the assumption about what happens in a test jig and projecting that into real world use. I'm more curious about how kayaks faired falling off cars or dumping surf or in typical rescue situations.

The Guegeon folks have a quarterly publication with a few different tests of panels to be used for the deck of a big wood boat. The interesting data there had to do with resistance to repeated cycles of impact as well as impact strength.

There is a neat little book about building whitewater kayaks,the author used the data from somebodys masters thesis as part of the info. In that book there aare rough graphs showing force/deflection relationships. The interesting thing I got out of it was that propogation energy,or how impact is transmitted through a laminate, is as important as impact strength.

I get the sense that there is a balance between the thickness of wood used and weight or type of cloth that is optimum for both. Two little glass or whatever and the laminate strength is dependent on the wood, or the laminate is vulnerable to being weakened by slight surface damage to the cloth. Too little wood and things get pretty flimsy.

When I made my North Bay I though I would be frugal with the epoxy by lightly sealing the wood prior to assembly. I was frugal,but one thing I noticed is that the bottom of the hull doesn't appear to be very resistant to dings. So maybe well soaked plywood is a good idea for the bottom. Or maybe I'm using the boats more.