Question: we are planning to insulate the interior of our new aluminum boat with spray foam, any comments? is your hull foamed? was it primed with paint be. Re: is foam insulation below deck of aluminum boat necessary? foam in small boats is usually there to keep the boat from sinking to the bottom if it fills with water.. Drips from condensation can be a nagging problem on a voyaging boat. controlling condensation belowdecks condensation can be prevented by adding insulation.
