Marine foam question

[Jgraham389]

I am removing the water logged foam from my tri hull. The boat only has 2 stringers and no horizontal beams. This results in 3 sections running from mid-bow to stern. The whole thing was filled with foam. The stringers are rotted. My question is: Should I fill all 3 sections again with foam or just the 2 outer ones and leave the middle open for water to exit?

 

[Watermann]

Re: Marine foam question

Some guys use cut in half PVC pipe laid down the center to create a limber channel for the water to move freely to the bilge and just foam over the top of it.

 

[idonthaveaname]

Re: Marine foam question

I would remove everything, replace the stringers, glass it up, replace the deck, drill holes and fill the entire void with foam like before. Then glass the deck (sealed) so water does not penetrate. Below your deck should always remain dry and if it's not it's because you have a leak.

 

[jigngrub]

Re: Marine foam question

I would remove everything, replace the stringers, glass it up, replace the deck, drill holes and fill the entire void with foam like before. Then glass the deck (sealed) so water does not penetrate. Below your deck should always remain dry and if it's not it's because you have a leak.

Yup!

Your boat is equipped with a deck drain and no bilge drain more than likely. Keep the deck drain plug pulled out when the boat isn't being used and the bow up. Any water that gets on your deck will drain out, and that will be your drainage.

Your below deck isn't really a bilge, it's not supposed to get water in it and it shouldn't need to drain. Filled solid with foam your below deck area will repell water.

The solid filling of your below deck area also supports and reenforces your deck and hull making them stronger by making it a solid unit/structure. This is why you only have 2 stringers and they probably aren't much more than (2) 2x4s layed flat.

There also isn't an over abundance or extra amount of floatation foam in your boat and you need all you can get to keep your boat afloat in case of an emergency.

 

[Jgraham389]

Re: Marine foam question

Good advice! My stringers are 2 x10s and the foam I am taking out is 10 inches thick. So, you suggest removing, cleaning, drying, replace with new stringers, glass them in, cover with plywood decking, then drill holes and inject the foam. And glass the decking, of course. Can you recommend the best foam to inject?

 

[glenn property of pam]

Re: Marine foam question

2lb 2 part flotation foam you will need to use a hole saw and cut about a 1.5 inch hole (save plugs so you can put them back in after foaming). The 2 part mix's for about 15 seconds then it starts to expand. I used a hand blender (better the mix better the expansion) and it was the most fun part of doing the boat.

 

[jigngrub]

Re: Marine foam question

Lots of people on this site use this foam:

Urethane Foam , Expanding Marine Polyurethane Foam

The vid in post #317 will give you a good idea on how to install the foam:

http://forums.iboats.com/boat-resto...18-complete-restoration-thread-585518-13.html