"two part closed cell foam " If you are talking about 2 part pour foam...the type where you mix part "a" with part "b" and it instantly starts growing and forming foam....be careful. If you mix this stuff in a closed container where it cannot expand as it needs to...or if it forms solid foam and blocks off its own exit while it is still expanding .....it can do some scary things! Just know that it IS going to expand....even if it needs to push you hull liner or cockpit walls out of the way to do it...IT IS going to expand! Make sure to carefully calculate how much you mix so you don't turn your Monty 15 into a Monty 19! Please do not ask that I relate how I became familiar with the expansion properties of 2 part pour foam!! :-) let's just say that I have had "confirmation" of some part of the above statement! Sean M23 "Dauntless" _www.havasumontgomerys.piczo.com_ (http://www.havasumontgomerys.piczo.com)