Pour foam - 4lb vs. 2 lb?

[DualCore]

Hi all, I wanted to get some opinions on what foam would be best to use in my boat (15' tri-hull bowrider). I know some of you will say not to use any and that is also an option that I am considering. ​

Originally there was some light foam lining the keel on both sides of the main stringer, but there was really not very much there. I am considering replacing it with some 4lb pour foam with the idea that this would add some extra structural strength (and support for the deck) in addition to flotation.​

Does anyone think this would be a bad idea? Could adding structural foam change the dynamics of the hull in a negative way somehow? Would it be better to stick with the 2lb which would be closer to what was used originally?​

 

[jerseysportfisher]

Re: Pour foam - 4lb vs. 2 lb?

that foam was more then likely used for sound deadening. If you want to replace it you need to find a pourable closed cell foam. This way it will not absorb water. I would leave it out personally.

 

[KurtG]

Re: Pour foam - 4lb vs. 2 lb?

Not sure I'd want the weight of 4lb, my boat (15' Henry O Mckee) supposedly has 60 cubic feet of 2 lb foam.

 

[DualCore]

Re: Pour foam - 4lb vs. 2 lb?

Thanks Guys!​

I didn't think about the added weight... I've been looking at the Urethane Pour Foam from US Composites and it says the 4lb density only has a coverage area of 4 cubic feet per 16lb kit (which costs $62 plus shipping). Not only would that get heavy it would be expensive to get enough to make a differance... The 2lb has double the coverage at 8 cubic feet per 16lb kit.​

I'll have to take some measurements of the space under my deck to see how much I would need to fill the area I had in mind. The stringer is only 6 1/2 inches high but I'm not sure on the width of the area off the top of my head. The length would be probably arount 10 feet.​

The no foam option is starting to look better and better...​

 

[metriccrescentwrench]

Re: Pour foam - 4lb vs. 2 lb?

US Composites sells pour foam, they recommend 2 lb. for boating applications. I'm finishing up a transom/stringer/deck replacement and used the 2 lb. foam from them and believe me, once it's finished curing it'll definitely contribute rigidity to the decking.

http://uscomposites.com/foam.html

 

[DualCore]

Re: Pour foam - 4lb vs. 2 lb?

metriccrescentwrench, yea that the stuff I've been looking at. How much foam did you need (for what size boat)?? I'm not sure how much it will take to cover the area I have in mind.​

 

[109jb]

Re: Pour foam - 4lb vs. 2 lb?

Not sure I'd want the weight of 4lb, my boat (15' Henry O Mckee) supposedly has 60 cubic feet of 2 lb foam.

UHHHH. 60 cubic feet??? No way. My 16 foot Sea Ray has about 10 cubic feet is it. I used 4 pound density and used 2 full 16 pound kits and about a half of another. 16+16+8=40 pounds of foam total. I went with the 4 lb because it is much more resistant to water absorption.

 

[KurtG]

Re: Pour foam - 4lb vs. 2 lb?

yep, unsinkable 3600 lbs positive flotation. More flotation than the comaprable whaler and built like a tank. Deck floats above water. I forgot the plug and only remembered cause the deck was slippery, but not wet.

I love this little boat.