Anyone ever used this for extra flotation on a decked jon boat? We used it at work to fill some 3' X 20' floats and it worked. The space I would like to fill is approx. 4-5 sq. ft.

Do you think its worth the trouble? I know it would be a mess to have to remove but I would rather float a little better when alone on the front of the boat.

Contrary to popular belief,  adding flotation to a boats interior doesn't make it more buoyant.

Unless of course you're sinking at the time.  

I agree with Zink. The GS applied onboard the boat will only help if your boat ever gets swamped but will not help you keep the boat trim in normal conditions.

OTOH, the only way that GS, or other stuff, would help trim the boat is if it is on the outside of the boat. Perhaps you could try to attach styrofoam to the bow of the boat? Like that blue styrofoam used for insulating walls?

HTH

Careful when using Great Stuff. I think it absorbs water. you need to use closed cell foam. I think Great Stuff is open cell foam.

Careful when using Great Stuff. I think it absorbs water. you need to use closed cell foam. I think Great Stuff is open cell foam.

LOL! Probably not good to have a sponge on the front of your boat. Ya might go down like the Titanic! LOL

The blue polyethylene is closed cell so I think this would be safe.

Zink you are correct. I hadn't thought about that. Hmmm Now if I were to fill it with helium... Nevermind it wouldn't last long HAHA

Are you sure Great Stuff is an open cell foam?  Well maybe the original stuff is, but there is another model that is closed cell.  I remember doing a boat project a few years back where we came a tad short on the 2 part expanding foam we were using, and then use Great Stuff.  I remember making sure at the time that it was the right stuff first.

Are you sure Great Stuff is an open cell foam? Well maybe the original stuff is, but there is another model that is closed cell. I remember doing a boat project a few years back where we came a tad short on the 2 part expanding foam we were using, and then use Great Stuff. I remember making sure at the time that it was the right stuff first.

I am not sure. I remember reading about someone wanting to use it as flotation foam and called the manufacture who said not to use it as that because it would absorb water. I tried to find it but could not. I guess a phone call to who ever makes wouldn't hurt.

I would think it's not only because it's meant to be used as a exterior sealer on houses. I would think they would have to make it so it wouldn't soak up water.

Bill

Looks like it is closed cell.

http://greatstuff.dow.com/greatstuff/diy/products/gc.htm

you may want to use the big gap filler

http://greatstuff.dow.com/greatstuff/diy/products/bgf.htm

I knew I wasn't crazy....... ;D

Pool noodles are a true closed cell.

Second hand knowledge now becoming third hand as I tell you.  I spoke to a guy who tied a pool noodle and a closed cell boat foam to the bottom of a swimming pool for a week.  The pool noodle came up dry, the boat foam was water logged.  If only we knew what boat foam he tested.