Thanks for the responses.

I wouldn't think strip builts would have this problem since their seams are spread across several relatively thin "panels" which would tend to distribute the stresses.

Every butt joint I've seen pictures of have an overlapping piece of ply across the joint, which is not really possible in the V of the keel. I was just curious why this didn't seem to be such a big issue with the keel. I guess something like a shear clamp piece could be added along the keel seam also but I guess it is because of the water pressure against the hull which makes the difference between the keel and the shear chine.

Anyway, just my mind working overtime, since I've become obsessed with kayaks lately. thanks.