TOPIC: Wet foam - what a pain

I started messing with the old 17' pointy looking boat, not sure what it should be called. Looks somewhat like a knockoff of the James Bond Glastron, but made by Reid Marine in Ft. Walton Beach, Fl in '73.

At any rate, the foam under the floor, and there was a lot, was all waterlogged. Along with the plywood. The boat itself is very well constructed. All hand laid, good construction, deck and hull glassed together all around.

Now, here's the thing that puzzles me. I've stripped half a dozen boats like this. I've hauled away truckloads of soggy foam. This is foam that is supposed to keep the boat afloat, and of course it wouldn't. So, when rebuilding, what do you use? The 2 part foam that is poured in? What is the difference between that and what I just took out? Have they changed it so that it doesn't soak up water now? Can you leave drainage below the foam, and maybe keep iT from absorbing water? What's a guy to do?

The subject of floatation foam has come up from time to time, even spawned a few arguments. Whether to replace it or not, and if so what material to use would likely bring ten different opinions from ten different enthusiasts. Like so many subjects we run across here, there's usually more than one way to approach the issue.

I believe the chemistry has improved greatly on the 2 part pour in foam, I'm sure what's on the market today will probably outlast what was used "back in the day" by a long shot. There are several good sources for the genuine "marine grade" stuff, available in several different densities. Pool "noodles", closed cell construction foam (sheet insulation), and several others have also been used by members with success. Some folks also choose to leave it out of the rebuild completely, it was required for the boat manufacturers to install it I don't know of any requirements to replace it after the original build process.

Is it a good idea to replace it with at least some form of floatation? Personal decision, but my thoughts are probably yes. The vision of my beloved project sinking like a rock leaving me bobbing like an apple in the middle of the like influenced my decision to replace it.

Most of our craft won't sit uncovered and neglected out in the elements for years, more than likely. Hopefully any compromises in the hull, thru-hull fittings and mounts, and other sources of water infiltration have been addressed. Proper drainage for bilge areas and better waterproofing (fiberglassing) of any exposed wood surfaces (internal as well as external) should also help prevent this problem from arising again any time soon.

Just my "nickle's worth", two cents doesn't seem appropriate when you're as long winded as I seem to be this morning! (sorry Austin). Looks like a nice project my friend, hope you keep us posted on your progress.

When I rebuild any boat with waterlogged foam, out it comes, and does not go back in. I'm glad my Power Cat floor is the hull, no foam of any kind to even worry about!

Good luck.

Frank

I left it out of the floor of the Glastron and made sure there was good drainage in every way to get water from getting stuck. There was foam that was completely dry in the gunnels and I left that in.

My theory is that there are enough air pockets in the floor to prevent it from sinking. At least for a good while...

I tried a few pool noodles in the Feathercraft and they deteriorated after a few months but were exposed to UV light.

I agree that new foam is probably superior to original. If I were to use it,I thought I'd lay a piece of PVC split in two along the keel line to allow water to drain if it invaded the space. My brother in law has a new power catamaran that uses foam in it's floor.

If you do use foam, careful, it will expand greatly and will push a floor up if you use too much. Did this on a sailboat!

Austinsailor,

GREETINGS from The Alamo City, neighbor to the North!

fwiw, i like POOL NOODLES to replace foam, provided that they are NOT exposed to sunlight.
(like hidden under the deck, gunnels, behind trim panels or under the floor)

note: i got a bunch from a bankruptcy sale of a "sporting goods store" for PEANUTS last year, that went into a friend's boat.

BEST WISHES, satx

I spent many years in charge of testing boats for flotation for the US Coast Guard, and this problem of soaked foam has been around for decades. Originally manufacturers were only required to build the boats so they would be in compliance for five years, so if the foam lasted five years, all was well. Now it's ten years. But actually not much has changed in the foam with one major exception, In 1995 the EPA changed the rules for blowing agents. A blowing agent is what make the stuff foam up. Prior to 1995 the foam manufacturers used HCFC's, pretty much the same stuff that was in aerosol cans. The EPA Banned HCFCs. After 1995 they used hydrocarbons or water (remember that last one. There will be an exam) But primarily water.

That's when the water absorption problem really went into high gear.

But getting back to the original problem, foam is actually a very fragile substance. It is susceptible to heat and cold, shock and vibration, and does not survive freeze thaw cycles well. People leave their boats uncovered and they fill up with water (and snow in northern climes) and it freezes and thaws. What happens is this breaks the cells. So what were closed cells are no more. There are a lot of other things going on too but it would take up too much room and bore everybody.

I would replace the foam, and I did on my 1972 Sea Ray, but I did not use pour foam. Research I have been involved with shows that this problem does not exist with pre-made (factory made) block foam. I used sheet polystyrene insulation foam. It is 2lb density (same as pour foam) and cheap. You can get it at home depot. I used the pink stuff. It has smaller cells and a higher density that the white foam. BUT, it will be dissolved by gasoline, oils and other chemicals, so if you put it under the floor or any place it may be exposed to those, it must be sealed in bags, glass, watertight chambers, or in some wya protected. And polyester resins will dissolve it too so you must use epoxy resin. I bagged it in sheet plastic, and tried to make the compartments watertight.

Polyurethane foams, (pour foam) are not affected by any of those things, but it is the culprit in all these water absorption problems. It is very finicky stuff and you have to follow the manufacturers instructions to the letter. If you don't you end up with lousy foam that absorbs water, or maybe it doesn't foam at all. (when this happens it looks like bread dough, or a cow pie) If it gets too hot it expands too fast and ends up looking like broken glass, because that's what it is, All the cells break. So if you decide to use 2 part foam, be very very careful/

In my opinion this information needs saved for future use. I still have the original blocks of foatation that was in my 59 Winner. It is stored in black plastic bags for about 5 years now. What concerned me is that the outside layer comes off powdery. It is block form. I may use it if I can secure it. It was originally under the seats. But was coming out when I got the boat. I'm getting to the point I need to think about what I'm putting back. Thanks.