Foam!!! Hate it but need it...

So working on a rebuild and just got all the foam ripped out of the front half of my boat (all waterlogged). Where my question comes in though is, is the 2 part expanding foam really worth the time and effort? I've been thinking about just using closed cell foam boards and cutting them to size and stuffing them in where ever I can. What are the pros and cons to this? I know the expanding foam will get in more of the small areas but is this really going to be a big enough difference to sink the boat? Half of me doesn't even want to put any foam back in it lol........ in case you couldn't tell I really don't like working with foam and prefer to keep that portion of the build as painless as possible.
Thanks

I'm using pink sheets from Home depot. Much easier than expanding foam.

Now I'm concerned though because since tearing into my back deck I've found that the back deck is primarily supported by the expanding foam

kalninm said:

Now I'm concerned though because since tearing into my back deck I've found that the back deck is primarily supported by the expanding foam

Click to expand...

Expanding foam is tricky though ... if you use too much, I've seen it BLOW APART the decking of frp boats ... imagine what it would do to a tin boat?

Sounds like you'll need a structural member/framing added if you intend to use the flat sheets of foam board, which from the sounds of it is what I'd do in your shoes.

I'm adding aluminum angle to mine to shore up the structure.

That may be the answer, I'm planning on do the expanding foam up front but I'm really not a fan of the foam being the only real structure holding up the back deck, so whether I use expanding foam or foam sheets its gonna get more support in the back. I guess a main question would be, if I fill all the areas with the foam board that was previously filled with the expanding foam would I have enough to consider the boat safe? Obviously there will be some air space in between the pieces of foam board I add, that pretty much what worries me

I agree with what you're seeing. The 2 part foam supports the entire rear deck. When I did my rebuild, I found that the only water logged foam was in the bottom inch or two. So I left 90% of the foam in the panels in place and cut out the bottom 2 inches. then I slid 2" foam panels underneath to replace what i took out. it worked well, and I've been fishing on it for 4 years with no issues. I would leave in whatever you can, otherwise you'll need to rebuild the structure as previously mentioned.

Good luck!

Its all gone :lol: the top of the foam was just disintegrating when I would push on it at the top, and thats not good cause thats when it starts sucking up water like a sponge, thats why I took it all out.....but yeah its all gone lol

I also left most of the rear sides in. In your case I would take some aluminum angle and run it from end to end long ways and rivet it to the under side of the deck panel I would imagine that would be enough to stiffen it up


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The boat manufacturers use the 2 part foam because it meets USCG regs for gasoline exposure & flammability, & probably a few other factors too.

The rigid polystyrene insulation board that I also used is dangerous when exposed to gasoline, but I am not manufacturing the boat, just using it at my own risk.

I figure if it catches on fire I don't want to be hanging onto it anyway.

Part of my flotation plan includes an old water sack, still holds air well.

The big factor is making sure the floatation element is adequately tied down!

When I added a deck onto my 1656 G3, I used loose blue foam "boards". I wanted them to have some slight movement so that water could find its way back to the stern. Support for the deck was supplied by aluminum "beams".

In your case, ...after you provided some sort of channels for water to flow through....you could add a modest amount of pourable foam in the lowest portion of the hull. Then, immediately add enough loose boards to raise the foam high enough to provide the support that you need.

You'd have to load in an extra board or two, and then maybe shave some off to match and support the top deck.

Just musing over your issue.
Rich

Thanks guys I'll probably go with the two part expanding foam, just seems like the overall best option although the foam boards would probably be easier, if I come up with something else I'll let you know

Thanks guys