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Don't forget to carefully insert foam between the cabin liner and sides. Every little bit helps and there's nothing in there.
Ix

Wrong kind of foam.

Yeah, different foams, expanded and extruded polyethylene, polypropylene, polystyrene (peanuts) will all give you floatation. They all (including factory foam) slowly absorb water if left in contact with it, and take an extremely long time (just like fibreglass does) to dry out if they have absorbed any.

As a side note, I've noticed that foam that has absorbed water, and then allowed to dry, will absorb water much more quickly the next time it gets exposed to it. Something changes in it once it has absorbed water.

There are some organic starch-based packing peanuts that dissolve (almost instantly, so easy to test for) in water, so stay away from those, !

BOAT wrote:Wrong kind of foam.

which one?

seahouse wrote:Yeah, different foams, expanded and extruded polyethylene, polypropylene, polystyrene (peanuts) will all give you floatation. They all (including factory foam) slowly absorb water if left in contact with it, and take an extremely long time (just like fibreglass does) to dry out if they have absorbed any.

i will test the foam to see their buoyancy properties

seahouse wrote:As a side note, I've noticed that foam that has absorbed water, and then allowed to dry, will absorb water much more quickly the next time it gets exposed to it. Something changes in it once it has absorbed water.

i just want to buy a little more time ( more than 3min )

thnkx for the tip

That foam in the picture is the kind that leaks and can get soggy. Same thing with the foam in the can - after a while it can absorb water.

You need that kind of foam they use in the boat - it can crumble into a million peices but it will never absorb water or sink.

I don't know what they call the different kinds of foam because I am not a foam expert but there are material engineer guys here like seahouse that know all the chemical names and stuff and they can explain better. I know because they told me a while back.

BOAT wrote:I don't know what they call the different kinds of foam because I am not a foam expert but there are material engineer guys here like seahouse that know all the chemical names and stuff and they can explain better. I know because they told me a while back.

the perfect foam is the "close cell" type

but as seahouse wrote "any foam will float"

Yeah BOAT, the stuff from the factory (expanded beads) absorbs water too (as do the other types), but slowly of course. The closed cell- vs open cell terminology applies to the springy foam rubber that seat cushions etc are made from, which is a different beast from these "hard" foams. In the case of the open cell foam rubber, it's what gets used to make (absorptive) synthetic sponges.

I have certain packages coming into my job that uses those "peanuts" type of foam packing. They melt (completely and within a minute) once submerged in water. I can run em down the sink, like putting hot water on ice cubes. Not all foam floats anymore.

Rumdirty wrote:I have certain packages coming into my job that uses those "peanuts" type of foam packing. They melt (completely and within a minute) once submerged in water. I can run em down the sink, like putting hot water on ice cubes. Not all foam floats anymore.

Yup. These are the starch-based peanuts I referred to above. They can be messy if your hands are wet too!

Rumdirty wrote:I have certain packages coming into my job that uses those "peanuts" type of foam packing. They melt (completely and within a minute) once submerged in water. I can run em down the sink, like putting hot water on ice cubes. Not all foam floats anymore.

good to know

im gonna stick to close cell foam

i will fill the fwd berth, port & starboard compartments and the back, i will post pics of the progress

On the "life " of foam

I capsized an Islander 17 on a lake with crew of 5 and was happy to see it stayed on the surface. This boat was in rough shape and I was surprised the flotation system still worked.

AFTER 24HR SOAKING ON THE POOL HERE IS MY CONCLUSION

Salt water is more dense than fresh water because salt water has more mass than fresh water. According to the formula of density, it's D=m/V. D is the density, m is the mass, and V is the volume. The more mass and less volume, the more dense the "solution" is. The less mass and more volume, the less dense the "solution" is.

back to the foam... I just test the three FOAM boards that i got (two close cell, one semi-open cell) this are my findings





all three FOAM blocks hold flotation, even the open cell, I use 2 concrete blocks to hold the FOAM in place

the open cell was the most water absorbed during this test with a drying period of two hours +

So...im going to use the close cell for the lower compartments and the open cell to some walls and upper side pockets

remember, im not saying that im safe with this foam, im just saying that its better than the emptiness i have now



Now i will start craving FOAM... ohhh Joy!!!

Hello,
Why bother using foam that you know will become waterlogged?

I would recommend staying away from things that could put a hole in the boat. Much easier.