> Take an egg, empty it's liquid content, and then see how it holds up to
> compression loads. Hint, it isn't very good now. The egg (really any
> spherical shape) works well in compression provided that (a) the load is
> symetrical about the entire body), and (b) it has an absolutely perfect
> body or a core.

That blows a good hole through my analogy. Not that that's bad--I wasn't trying to change the world; just had some random thoughts that didn't jive with conventional wisdom.

> The marine study you found about boat hulls was very good. But I think you
> missed a key point. He was lambasting not cored hulls per sey, but the
> elimination of adequate skin strength for impact and abrasion. Thats why
> he mentions turning the hammer around. That key point is one that you the
> builder must decide. I know I'm rather hard on things, so I overbuilt my
> hull to be able to take hard sharp blows.

But in this case, more glass on the outside would be stronger, right?

> You must also accurately model your own loading on the boat. Are you going
> to be bashing it into pointy rocks, or are you going to be loading it by
> wave action. The two are completely different in their application of
> forces, and the requirements of the body. This is why powerboats like
> Bayliner are perfectly adequate for recreational boaters, and sink if they
> are worked commercially. A Bayliner can comfortably handle wave action,
> but holes if it sees ice flows.

Both. It will see some sharp pointy rocks, plenty of wave action, and also abrasion from being dragged onto a beach. I think Bayliners are also in the same category Pascoe epitomized with his description of Glastrons. They're built with chop guns. Hand-laid hulls with long-fiber cloth are much stronger, pound for pound.

Shawn