What to use for flotation foam

[sstout]

This might be a repeat of a previous thread, but what do people recommend for flotation foam under a new floor? First thing this spring, I am gutting my boat and sealing the rivets with Glu vit. Then replacing the foam, floor, and installing a completely new interior. 

 

I don't really want to use ping pong balls or pool noodles. I'd like to use actual foam if possible. Should it be closed cell, open cell, and where's the best place to get it? 

 

Thanks in advance

[Frogger]

Closed cell definitely. 2 part foam from Jamestown dist I think I used 2lb for a floor project I did. Many companies out there to find the best price. Don’t let it get on anything.


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[Egoody]

A word of caution if spraying closed cell foam....Follow the application instructions!!!

As closed cell foam cures it goes through an exothermic reaction that causes it to heat. if applied to thick it can become hot enough to catch fire.

I know this because a company applying closed cell foam insulation in my attic sprayed it thicker than specified and it caused a fire in my attic. 

 

Thanks and Boat Safe,

Egoody

[scobar]

You can 2 part liquid foam, closed cell for sure. Pricy but very good stuff.


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[Tradman]

http://www.uscomposites.com/foam.html

[BottomDollar]

Closed cell blue or green foam panels work well for aluminum boats and it's cheaper and easier than 2 part spray foam.

 

[Fishnut]

ping pong balls. they don't take on water ever. they will out last your floor sore sure.

[Rookie Fisherman]

Here is my 2 cents.....

 

The foam panels, pool noodles, ping pong balls etc might be ok for a small boat on an small Adirondack pond or lake.

But for Lake Ontario I would not use anything but a Coast Guard compliant spray foam. Spray foam will fill the cavity you are applying it in 100% simply giving you more flotation and no (or certainly less) voids for water to collect or get trapped.

Lets say god forbid you hit something in the water that punctures a hole in the hull and you start taking on water. Which product would you want? 

 

The other consideration is resale. Not sure I would buy a boat filled with pool noodles.

 

To the guys who have posted above please understand not trying to pick a fight or debate the topic just think there are some more things that should be taken into consideration especially when safety is a involved.   

 

 

Edited March 8, 2019 by rookie fisherman

[sstout]

I like the idea of spray foam, but how do you apply it so that any water that happens to get in the bottom of the boat for some reason still gets to the back where the bilge pump is? With the sheet foam it would sit on top of the stringers which would allow any water to flow back. 

 

I appreciate all the ideas. Certainly more choices than I first thought. Thanks

[scobar]

you can buy a 2 part liquid foam, mix together and pour, you have about 30 seconds to pour in. You can do this in your garage, no need to spray and it is coast guard approved. West marine does carry it and will price match if you ask them too. 

Being closed cell very little water if any gets into it so the path to the stern may not even be needed, adds a great deal of structural support as well

[garrymny]

I would not use a spray on foam. When I restored the old cimmaron it was loaded with water logged spray foam. Very heavy and was just like a sponge. Also, it prevents you from seeing the structure if you ever want to inspect it or work on it. When I got the Grady, I filled the huge hollow spaces with pool noodles. They never absorb water and can be removed easily if I ever need to see something.

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[VooDoo]

US Composites out of Fla. has the best price on marine foam. Just replaced foam and floor in my boat. Note the very center and deepest part of the hull has no foam. This is where water drains to the bilge area

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[rolmops]

There are a few very good youtubes and also i-boats articles on pouring foam. Here are a few tips about doing it.

Get a bunch of large cheap disposable quart and gallon plastic mixing and measuring jars or cups and a few mixing tools that you can put on your drill for mixing the parts together fast

Make the entire floor of your boat ready and install it. With a hole saw drill a bunch of holes and keep the pieces that your hole saw cut out.( you will need them). Wait unlit the weather comes up to 80 degrees.This is a needed temperature for proper foam expansion.

When it is warm enough to work, mix the foam fast and pour it into the holes as it begins to expand (not before) starting at one end.caught between the flooring and the hull  the expanding foam will  expand upward and once it fills that direction it will expand sideway because it has nowhere else to go. The moment the foam starts to come out of a drilled hole push it right back with one of the drilled out pieces of wood that you saved and put a brick or some other weight on top of it to keep it in place. In the meantime pour more foam into the next hole farther down and so on. That way your entire sub floor space will be filled evenly and completely, not leaving any pockets where water may gather and freeze. It is freezing water that expands and destroys closed cell foam.If you do it right, it will get very hot so bear that in mind. If you do it inside, make very sure to have good ventilation. The process uses up the oxygen and stinks bad. Keep in mind that you will have very little time between mixing and pouring

Hope this helps.

Cornelis

 

As for pool noodles, pingpong balls, soda bottles and milkjugs. These thing will not pass coast guard inspection.

Edited March 31, 2019 by rolmops

[garrymny]

In my case on the Grady, the pool noodles I put in are in addition to whatever the manufacturer put in. On the cimmaron I restored there is no way the coast guard could ever see under the floor to make an inspection. In it, I used the blue and pink insulation foam under the floor. After my experience with the restoration, I would never trust the spray or pour foam. I think once the hardened surface is compromised, the water gets in and it becomes a sponge. Just my opinion obviously, and everyone has to make their own decisions.

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