Capn,
Check out this picture...

I've rabetted 1/2" plywood hard edges into the foam, with the plywood extending 2" past the foam. The reason is so that the foam can sit on the trailer in compression; but I drive screws through the plywood edges, into the floor and spars.
I also have gorilla glue on the foam to the floor, and on the hard edges to the floor. Screws, of course! And adding canvas will give me triple redundancy.
I was a little bit concerned about the wind too. The day we glued up the walls it was quite breezy. Surprisingly, the screws held the wall very securely. Of course we added a temporary spar across the top as soon as we could.
I've made one very big error though. The galley spar, the one that the hatch hinge mounts to is only glued to the foam, not the hardwood edges. When I glued the roof panel on this afternoon, the joint broke. I currently have it sitting in a pool of gorilla glue, with a pipe clamp on it. I'll know tomorrow if that's still going to be an issue. If so, I'll have to perform major surgery, and extend the hatch spar down to the hard edge.
Mike...
capnTelescope wrote:Great progress, Mike!

Foamie noob questions:
mikeschn wrote:Then I glued up the walls...
Glued what to what? Baseboard to the floor edges? Foam to floor surface? Both? Something else? No screws?
With what? TB2, GS, something else? BTW, I found that TB doesn't stick all that well to poly.
How'd you keep the walls upright while the glue set? Seems to me they'd fall over if you sneezed.
I'm learning as you go.

The quality is remembered long after the price is forgotten, so build your teardrop with the best materials...