Just a minute!
Two-part foam is not necessarily a good solution either.
Some of 'em will soak water, getting heavy and encouraging rot and mildew.
They prevent access for repairs and wiring, etc.
THey're not cheap, either.

Have you considered inflatable items like truck tubes?

Tailgunner wrote:

Here are my conclusions regarding that long thread I started about using
Ping Pong Balls for floatation..

Ping Pong balls are not cost effective. $20/144
PPB burn real nice.
PPB are relatively fragile.

2 Liter Soda Bottles are cost effective.
2 LSB can withstand the temp changes here in New England.
2 LSB looses volume quickly under external pressure. Designed mainly for
internal pressure.

Both will degrade in direct sunlight.

What will I do? More than likely I will fall in with everybody else and
use 2 part. I'll just have to make allowances for moisture to be able to
flow from bow to stern. With either of the other methods I would not
have to do this.

Thanks to all that posted.

--
Tailgunner
http://boat.nbrigham.com