Thanks Brian, I wasn't aware of that. I assume you mean heat from air
temperature and sunlight. Is it a significant amount, and would the less
dense foam have less force? I'm wondering if he could somehow pour a limited
amount of the liquid into the inverted boat so foam would adhere to the deck
to give support yet not fill the tank. But I doubt the bond would be
sufficient to do this, especially over time.
My other concern was any problem of the foam eventually soaking up water
from the inevitable leak.

"Brian Whatcott" wrote in message
...
On Tue, 19 Apr 2005 20:55:34 -0400, "Garland Gray II"
wrote:

Polyurethane foam bulges long term after heating.

Brian Whatcott Altus, OK