Tom,

After some discussion between myself and a couple of mechanical engineer friends we've decided the primary reason for the amount of flex is due to two factors. First, my chines are barely over 1/2 inch by 1/2 inch so they are going to be more flexible than the size you recommend. Second, I didn't secure my chines at either end of the boat. IE I removed crossbrace 8 (I think) and didn't tie the chines into the stern or the bow plate. As a result they are free to move more than if I had secured them in place.

I think this is the major cause for my weathercocking issue as well. I'm probably going to retrofit a hatch into the rear of the boat, so I'll also insert a station or at least tie the chines into the stern at that point. That should reduce a bit of my flex and drop the stern further into the water to help track better too.

Thanks again for sharing your designs with us all.

FrankP