77 Forester tri-hull - floor replacement - is xps foam ok?

[82ndjm]

Greetings. I apologize if this has been covered before but I have not read every thread....yet. I removed the floor from my tri-hull. Not what I expected to find, but this is my first experience trying this. There are no stringers, just a fiberglass bilge "channel" down the middle. The foam I removed looked like 1" pieces of siding insulation laid on the floor with resin and mat on them. So...I was going to replicate this design using "XPS" foam insulation. Has anyone done this? If I did get two part pour in foam would that support the floor? Is the resin and mat over the insulation necessary if XPS is closed cell?

 

[jigngrub]

Re: 77 Forester tri-hull - floor replacement - is xps foam ok?

The 2 part expanding would be my first choice for an f'glass boat, and if I was on a budget with lots of time I'd go with a 2 part expanding/xps hybrid... but the 2 part isn't really that much more expensive and is less labor intensive than the hybrid.

I've seen some people use the sheet foam in their f'glass builds, but I don't consider it as good of a build as the 2 part, too many voids and no added strength.2 partdoes do a better job of filling all the voids and sealing your hull in case of a breach. The 2 part will also support your deck and hull, making your boat stronger and quieter.

 

[Woodonglass]

Re: 77 Forester tri-hull - floor replacement - is xps foam ok?

To answer your question, yes you can replicate what your found without issue. It will work just fine and offer adequate flotation for the boat. I would recommend putting as much in as you possibly can if you choose to go with it. The 2 Part pour in is quite easy to use and has a lot of advantages as mentioned.