To floatation foam or not to floatation foam?

Ghost

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Always liked the idea of ping pong balls until I saw them burn.


Can fast forward to 1:50
 

Ghost

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I replaced the floor in my boat 18' jon dory center console)20 years ago, the old foam was deteriorating and water logged,the foam in my skiff was used as structural support , I added gussets and ribs and refoamed leaving the fuel tank not foamed, about five years ago, at my old marina, in a mud slip, the boat sat on an old railroad tie with a big spike that put a hole in the hull, I hauled the boat cut the floor over the damaged spot to repair it, the foam hadn't absorbed any water, after the repair, I refoamed it, patched the floor and still hit max RPM with the same engine and prop..the new stuff is definitely better than the old, like others have said, it has its place
.my transome is the original from 1977, its wet but solid, should I ever replace it, I'd refoam again..
What type of foam did you use? (Guessing maybe US Composites 2-part expanding foam?)

Thanks

Mike
 

RKrough

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When I was replacing stringers and deck on my Midland, I went back and forth on whether to foam or not. I ultimately did decide to foam with a closed cell pour type I got from Merton’s. What I did differently was I split some 2” plastic pipe drilled it full of holes and glue it to the bottom to provide a path for water to escape to one of 3 wells accessed by a 4” deck plate. Any water that collects can be sucked out with a shop vac. Probably unnecessary extra work and money, since it has stayed bone dry for the past 10 years. It does to give the Coasties and local water Barneys something to get excited about when they do their searches.
 

Fast Eddie

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I used to have an Ensign and we regularly raced in the Winter in NC. One of our crews was out practicing on a day with some wind and their boat swamped and sank. They were in moderately cold water for awhile and we almost lost them. Next week we took a look at our Ensign and we filled everything we could reach with plastic soda bottles! I think we all got lucky.
 

Busanga

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That stuff soaks up water over time. Search for my thread on Tip Jar. I pulled a bunch of it out. All saturated.
learn something new everyday. am surprised. i have found lumps of it floating in the seas here which looked to have been there along time. still bobbing along.
 

kapnd

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Any flotation compartment, foam or air should have a low point drain.
RKrough’s idea with the plastic pipe for drainage is right on, I’ve seen so many boats with foamed in fuel tanks that failed prematurely due to lack of drainage.
Closed (air) compartments can be fitted with a drain valve.
 

MAArcher

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Any flotation compartment, foam or air should have a low point drain.
RKrough’s idea with the plastic pipe for drainage is right on, I’ve seen so many boats with foamed in fuel tanks that failed prematurely due to lack of drainage.
Closed (air) compartments can be fitted with a drain valve.
Was the problem that they had lack of drainage, or that something went wrong that they needed to be drained?
 

Busanga

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I think I've seen rafts/swim docks in lakes floated with big blocks of that stuff so I just did a quick search and see that it is used for that:
Marine and Dock Flotation | Universal Foam Products | Styrofoam & EPS Foam Blocks & Sheets
yep that is what i am talking about.. have seen it used out here on the water for years by the local canoe fishermen. never seen it saturated...but then i may not just have been looking


Quote:

Polystyrene foam is used to make the hulls of many rafts and rescue boats, such as the U.S. Coast Guard's Defender class, because it is shock and heat resistant.

End Quote
 
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Cmschlatt

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have always wondered why polystyrene is not used, it doesnt absorb water. floats around the ocean forever. they make cool boxes out of it and they never get soaked (old, cheaper style coolers with no plastic moulding around them)

i assume there is fire retardent versions, or maybe not ?
I think polystyrene dissolves when fuel is applied
 

Alisske

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Polystyrene is extremely light, am talking about the stuff they use to pack your TV in, lighter than polyurethane foam
Gotcha. Like the pink stuff in sheets. Yeah. That stiff does. Not seem to absorb water at all
 

Busanga

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Think i will start a company making sealed plastic cubes of various sizes which can be packed into bilges for flotation. or pump up bladders like fuel bladders :)
 

Amelia Man

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I have had a problem with termites in my stringers. Boat is being tented this weekend. I am looking at using Polyurethane closed cell foam to fill the voids. If I use a 4 lb. density I get a free rise core density (FRC) of 4.25 pcf and a Core density in a mold or inside a stringer of (CD) 7pcf with a compressive strength of 150 psi. If I go up to an 8 lb lb foam I get a FRC of 8 pcf but in a mold or enclosed stringer I end with CD of 18pcf and Compressive Strength of 500psi. 500 psi is enough to support my diesel engine and feel tank. The theory being that the skin will be stronger and adhere to the stringer walls.
They also have 2 lb density foams for flotation use. 1 2 gal kit would provide about 10cuf of foam enough for most boats. they also sell it in 2 quart kits for small projects.
I got the information from NCFI Polyurethanes a division of Barnhardt Manufacturing Co. Mount Airy NC 27030 Great people and very helpful. 800-346-8229
 

Cool Boat

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We salvaged my friend's floating dock made from a pontoon boat a few years ago, Polyumac two part foam did the trick, still holding up fine. We used that same foam in the yacht tenders we built. It added the USCG required flotation and considerable structural rigidity. I would suggest the 2 lb per cubic foot for flotation and if structural rigidity is lacking, upgrade to the 4 lb.
 

Kenneth

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What was your procedure for installing that foam? Did you put some sort of no-stick temporary deck over each compartment after pouring? Thanks
I poured it higher than the surface, then cut it off flush and installed the deck.
 

Busanga

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this is a comment about someone pouring foam into a deck through holes...

You screwed that one up royally. In fairness, you clearly didn't understand what PolyIso (part A) does so here's what happened: When you dumped a ton of foam into those holes, it expanded and a thermal reaction burned the inside of the foam. So you now have voids between your foam. This is why professional foamers don't lay down more than about 4" on a pass. Hell, if you're using a Dow froth pack you're not supposed to exceed 2". Also, you're supposed to be using a respirator (the one with the magenta cups on the sides would be sufficient for a well ventilated area) and proper eye protection. There are reports of some people having fires when they go that thick with foam. On the plus side, even though there are charred areas in the center, the outside is probably still solid so barring cracking, those areas should still hold air. If you do it again, lay down the foam with the top off and make passes, trying not to exceed 4", allowing the foam to cure before building up to the height you need. Then, when you have 2-4" below the deck, you should have a decent understanding about yields and you could finish it up with a technique similar to what you did.
 

Genius

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this is a comment about someone pouring foam into a deck through holes...

You screwed that one up royally. In fairness, you clearly didn't understand what PolyIso (part A) does so here's what happened: When you dumped a ton of foam into those holes, it expanded and a thermal reaction burned the inside of the foam. So you now have voids between your foam. This is why professional foamers don't lay down more than about 4" on a pass. Hell, if you're using a Dow froth pack you're not supposed to exceed 2". Also, you're supposed to be using a respirator (the one with the magenta cups on the sides would be sufficient for a well ventilated area) and proper eye protection. There are reports of some people having fires when they go that thick with foam. On the plus side, even though there are charred areas in the center, the outside is probably still solid so barring cracking, those areas should still hold air. If you do it again, lay down the foam with the top off and make passes, trying not to exceed 4", allowing the foam to cure before building up to the height you need. Then, when you have 2-4" below the deck, you should have a decent understanding about yields and you could finish it up with a technique similar to what you did.
Careful “new guy”:rolleyes:
 


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