Filler Foam

I have A 18' Chaperal 1979. The deck was getting soft so we cut it open only to find out the foam was saturated and the stringers are rotten. We removed all the foam and replaced the stringers recreating 9 compartments. My Question is the middle bays on each side had no foam, Should I fill these bays or just do the for and aft bays as they had been :?: and why? Also what type of foam should I get? And where do I get it?

 

Fat Sam,
I am in the middle of a rebuilding my dad's old 1977 19' Chaparral... I had the same problems. I am not stating this as the right way of doing it, but when I was done rebuilding the stringers and replaced the deck I poured foam under the deck in any place it would go. I planed off all the foam that squeezed out the cracks and relief holes I drilled, and fiberglassed over the whole kit and kaboodle. That being said, be careful because that foam is extremely strong once it starts expanding, and will start wreaking havoc if it don't have any where to go. The deck is now rock solid and should be alot quiter, not to mention it wont sink like a rock now. My .02

 

Thanks for the reply.
What type of foam did you use and how much? Where do I order foam?
Thanks again,

 

Fat Sam,
I puchased my foam at USCOMPOSITES.COM I was very pleased with the service they provided. For my 19' Chaparral, I purchased (2) gal. kits, and a quart kit. This filled ALL the space under the deck from the transom to the bow. I lucked out and ordered a perfect amount. They have a calculation you can use to calculate how much you will need for your application, but I would assume it would be about what I used if you plan on replacing all the foam under the deck. It was surprisingly easy to mix (2-part) and work with. Another person present helps. I had a buddy mix it up while I poured it. Again, use caution when pouring it into confined spaces like I did. Once it starts expanding, if it dont have no where to go, it will start tearing stuff up. I drilled 2" holes every couple of feet and started pouring toward the transom and worked my way towards the bow, closing off the holes as I progressed (if that makes any sense). I mixed small amounts (quart at a time), and slowly worked my way towards the bow till it filled all up and came out the last hole. I used the 2lb. density closed cell polyurethane foam. It is USCG approved, wont absorb liquids, and you can fiberglass over it. Good luck. Shane

 

Sam,
FYI.. I bought (2) 16 lb kits, and (1) 4 lb. kit..sorry