Dave,
Just back from a big boat builders boast show convention. I had several conversations with folks using various closed cell materials.

Folks are striping with such things. I haven't heard of folks trying to pin these things in place as much as they are trying to work with the flex over a larger expanse.

I think your idea is incredibly inventive. However, I am concerned that as the boat flexes. Your foam cell might locally pull against the skewers and tear.

I am thinking you might acheive the same thing with edge gluing, or using ways that transfer stress from the local pointto regional.

This is all hypothosis on my part. New ideas should be investigated. My thought would be to try making a few test sections and apply normal boat stresses to them and see how the skewers and foam hold up.

!RUSS