# foam flotation questions



## lemaymiami (Feb 9, 2007)

If the foam sticks to the hull and deck it adds a bit of strength to those areas... I’ll watch this thread to see what others have to say about this.


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## BassFlats (Nov 26, 2018)

Plastic sheeting would do the same and probably be easier and cheaper.


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## mro (Jan 24, 2018)

Saran wrap with a little masking tape to hold it in place...

The plywood to be installed after the flotation is installed. Plan to do every other opening (between ribs) then I can cut the foam even with the top of the deck supports then do the other openings.

I also plan to add cut to fit 2 x 6's on the ribs that don't get an aluminum support. the ribs just happen to be 1 1/2" wide so the 2 bys will fit nicely. Attached like the factory did the aluminum supports (have enough sheet aluminum). All ready got a hundred ss sheet metal screws, and have a couple hundred ss wood screws. think I might put a bead of 5200 between the rib and 2 by so there be no chance of any rattles.

Just finished making a jig for my table saw so I can cut the angles on the 2 bys to match the hull.


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## WhiteDog70810 (May 6, 2008)

I’d pull the foam and remove the Saran Wrap once set. I can imagine how a loose bit of Saran Wrap could burn up a bilge pump at the worst possible time in the future.

Nate


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## mro (Jan 24, 2018)

From what I've read that stuff sticks to everything but good idea to check.

The section at the transom will be left "un-foamed" and the center part (about 16" wide) where the drain plug is will be left visible plus this will be where the main bilge pump will be. Up front at the deepest part of the hull I'll route a hose to there and connect it to a 12V flo-jet pump which can self prime. Then I'll keep a backup bilge pump under a hatch with a 10 ft cord and plug so it can be placed anywhere in the boat during an emergency. I've always had a backup pump, battery and sometimes fuel. Never needed em all these years and hope that I never do.


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## jasonrl23 (Jul 27, 2009)

Mann Release agent looks promising. Anyone try it for foam?


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## DuckNut (Apr 3, 2009)

If you put the two part foam under there in a few years your boat will weigh an extra several hundred pounds because of all the water it absorbed.

Find a source for the type of foam that pool noodles are made from (in sheet form). That plastic/rubber feeling stuff. Cut to fit and glue a few spacers to the hull to keep it off the hull and water can drain out and it can dry under the deck.

I think I saw the rebuild thread on this...where is it?


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## DuckNut (Apr 3, 2009)

I just found your other thread.

The foam you had in there was original - why not use that type again afterall it lasted many years?


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## mro (Jan 24, 2018)

At least half the Styrofoam I took out I plan to reuse but had thought to fill in any open spaces with the two part around the Styrofoam to make it "fit perfectly"  under the deck, no space between the plywood and foam. If i can find a source for larger pieces of Styrofoam I might just do that. 

The two part foam is supposed to be 90+ % "closed cell". If it starts absorbing water in just a few years F that... I don't expect any leaks but I do go out in the rain.


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## DuckNut (Apr 3, 2009)

mro said:


> At least half the Styrofoam I took out I plan to reuse but had thought to fill in any open spaces with the two part around the Styrofoam to make it "fit perfectly"  under the deck, no space between the plywood and foam. If i can find a source for larger pieces of Styrofoam I might just do that.
> 
> The two part foam is supposed to be 90+ % "closed cell". If it starts absorbing water in just a few years F that... I don't expect any leaks but I do go out in the rain.


The foam WILL start absorbing the moment it gets wet. Then it only gets worse. When the wet foam is in contact with the aluminum hull it will corrode holes in it.

In the past some boat builders foamed in their fuel tanks and they all leak because of this, but they have learned their lesson. Aluminum is a tough material but it needs to get air.


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## mro (Jan 24, 2018)

Thanks DuckNut,

good to know.
One thing I still need to do is clean out the inside center of the hull between the rib and hull.
There's only a very small gap but as the lowest points in the hull they do let the water "leak" to the back of the boat when the bow is raised. Right now there are several that are clogged.


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## DuckNut (Apr 3, 2009)

TheFoamfactory.com has 1"x48"x108" for $63. If they would cut it to the width between supports you would be in business. Buoyancy is a little more than 60lbs and one sheet would add about 270 lbs of buoyancy.


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## mro (Jan 24, 2018)

I found a local company today and they have 2" thick sheets in stock but have a $250.00 min order. Another company has them to but min order is 5 sheets. Have not found anything thicker. Some 4 to 10 inch thick would be nice.

I'll swing by them and see if they happen to have some slightly damaged sheets they want to get rid of.


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## DuckNut (Apr 3, 2009)

Since this stuff is made by expansion into blocks the size of a pickup there are always end and side cuts they discard to make a square block.


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