1976 Duracraft Flooring question

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Swampfox88

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I have an older 1436 and it has a flat floor I believe is from factory, the floor is riveted , I tried to lift a piece of the floor to see whats underneath, it appears to have foam and ribs. the foam is formed around the ribs (looks factory) The foam was sogging wet the little bit I could see from sitting in rain I assume, I now have boat in garage. My question is should I take the time, to take up floor and replace the foam? or should I let it dry and it will be fine? I don't want any added weight especially if its useless.floor boat.jpgboat floor 2.jpg
 
I don't think it will ever dry out properly. I just took out 150 pounds of waterlogged foam from my boat.
I'm going to start replacing the foam this weekend, I'll post my progress as I go.
 
Bad Wolf said:
I don't think it will ever dry out properly. I just took out 150 pounds of waterlogged foam from my boat.
I'm gooing to start replacing the foam this weekend, I'll post my progress as I go.

Thanks for the advice, I want to replace it , just seems like a lot of work. what type of foam are you going to replace it with?
 
does any one know if the side panels are full of foam or what is possibly behind them, the panels only run about 8 feet down side of the boat. If so do you believe they will need replacing. thanks in advance
 
I removed all the flooring, which was a huge pain, but I'm glad I did b/c there was 180lbs of soggy foam underneath. It will be a challenge to get back together, I now have touched every inch of my boat. The side panels were foam as well and I plan on replacing them too.

Any suggestions on a good cost effective foam to replace it with?bare floor.jpg
 
You were right to remove that waterlogged foam from the boat, it will never properly dry, and because it will hold moisture, it will create a condition known as 'poultice corrosion' which will eventually eat holes through your boat. The problem with factory installations is that they simply pour the foam directly in, and a lot of it will flow into the gutters, which stops proper drainage, as well as airflow underneath the foam.

You'll want to use Dow foam board (either pink or blue) to replace what you removed. Typically, it's 1.5 to 2 inches thick, but that depends on the height of your ribs. Using board allows the gutters to remain clear for proper drainage and air flow.

Before installing, I would recommend a thorough exam of the hull for corrosion where the foam was in contact with it. Then treat it with phosphoric acid, and rinse. Then, paint it with a good self-etching primer and a good epoxy, like Interlux Interprotect. This will stop the corrosion process in its tracks.

If done in this manner, the foam will stay nice and dry, extending the life of your boat, and your flotation foam.
 
foam board insulation from lowes or home depot is the quick & easy way

you can also use spray or pour foam if you block off the channels on the bottom of the hull w/ tape and trim it to rib height.

closed cell foam that's been cut is no longer closed cell & should be painted w/ exterior latex paint to prevent water logging, this applies to both foam board and spray or poured foam that have been cut

the spray foam should be MARINE spray foam, not great stuff! you can get marine spray foam @ west marine or other sources, you can also get 2 part foam that is poured

most folks opt for the foam board as it's a lot less work for a similar result, although the spray/pour will give marginally more sound insulation, strength, and flotation due to less voids versus foam board
 
Thanks for the advice guys, im going to clean it all tonight. I will probably use the foam board from lowes. Should I paint the entire foam board with exterior paint? or only on the sides I cut? If I only spray the self etching primer and leave out the epoxy will this suffice? or is it super important to epoxy paint it?
 
I don't think the cutting will affect the foam. It doesn't rely on a waterproof "skin" to work.

From a foam website:

Solid foams form an important class of lightweight cellular engineering materials. These foams can be classified into two types based on their pore structure: open-cell-structured foams (also known as reticulated foams) and closed-cell foams.

Open-cell-structured foams contain pores that are connected to each other and form an interconnected network that is relatively soft. Open-cell foams will fill with whatever they are surrounded with. If filled with air, a relatively good insulator is the result, but, if the open cells fill with water, insulation properties would be reduced. Foam rubber is a type of open-cell foam.

Closed-cell foams do not have interconnected pores. The closed-cell foams normally have higher compressive strength due to their structures. However, closed-cell foams are also in general denser, require more material, and as a consequence are more expensive to produce. The closed cells can be filled with a specialized gas to provide improved insulation. The closed-cell structure foams have higher dimensional stability, low moisture absorption coefficients, and higher strength compared to open-cell-structured foams
 
Swampfox88 said:
Should I paint the entire foam board with exterior paint?
no, see below


Swampfox88 said:
or only on the sides I cut?
correct, even a quick blast from a spray paint can would be wise


Swampfox88 said:
If I only spray the self etching primer and leave out the epoxy will this suffice?
yes, self etching primer will suffice


Swampfox88 said:
or is it super important to epoxy paint it?
no, but epoxy over top will last longer than self etching primer alone


Bad Wolf said:
I don't think the cutting will affect the foam. It doesn't rely on a waterproof "skin" to work.
cutting the foam will not make it water log over night, but painting it is easy and will only delay water intrusion. the foam is going to be sitting in the bilge area, so anything to make it more waterproof is probably a good idea, although not a necessity

from that foam website, these are the key words, when translated, mean that closed cell foam takes longer to become water logged than open cell foam:
Bad Wolf said:
low moisture absorption coefficients, (...) compared to open-cell-structured foams
this tells me that the foam will soak up water eventually, just like the factory foam did. the "waterproof skin" helps to delay this, that's why the foam board is shiny on the face, i'm not positive, but heat might also work, i've never thought to try hitting it w/ a heat gun & I'm unsure of its flammable characteristics
 
You have been super helpful!

One more question for you , if it was your boat would you remove the side panels(going up side of the boat). they are filled with foam, but take up a 3 inchs on each side of boat. Are these necessary or just a result of old design. the entire floor will have foam .
 
chevyrulz - good points all, painting definatly won't hurt and after all that work I would not want to have to redo it.

I'm counting on the fact that I'll try to avoid filling the boat with water in the first place, it will be brand new, I won't let the foam sit in the water, I'll give it an easy way to drain and I'll let it dry out between uses.

On mine I noticed there was a lot of volume that had no foam at all. I plan on filling these with foam as well.

Swampfox, I would fill the sides as well, every cubic inch of foam is that much more floatation should you ever get swamped. Plus I'm sure it would help with sound deadening.
 
I'd leave the side panels as they are since that's not really useable floor space. & if they're foamed, leave the foam or replace it since foam amount & placement are engineered to float the boat level if it's swamped.

that said, i doubt the side foam is vital, so if you have a good plan to make use of that space, then it's probably no biggie to remove the foam there.
 
chevyrulz said:
I'd leave the side panels as they are since that's not really useable floor space. & if they're foamed, leave the foam or replace it since foam amount & placement are engineered to float the boat level if it's swamped.

that said, i doubt the side foam is vital, so if you have a good plan to make use of that space, then it's probably no biggie to remove the foam there.


thanks again for all the help. I thought about taking the foam out the side, and sliding rods behind if I drilled a few holes on side it might work. I guess I really wont lose to much floor space. Guess I will leave them it will make it much easier to put old floor back in and rivets.
 
glad i could help, i think it is wise to leave them, a couple Rod Savers would be nice mounted to those existing side panels

like this guy did:

392103321.jpg
392103318.jpg


pics courtesy of this thread: https://www.tinboats.net/forum/viewtopic.php?f=3&t=15856
 
Bad Wolf said:
I don't think the cutting will affect the foam. It doesn't rely on a waterproof "skin" to work.

From a foam website:

Solid foams form an important class of lightweight cellular engineering materials. These foams can be classified into two types based on their pore structure: open-cell-structured foams (also known as reticulated foams) and closed-cell foams.

Open-cell-structured foams contain pores that are connected to each other and form an interconnected network that is relatively soft. Open-cell foams will fill with whatever they are surrounded with. If filled with air, a relatively good insulator is the result, but, if the open cells fill with water, insulation properties would be reduced. Foam rubber is a type of open-cell foam.

Closed-cell foams do not have interconnected pores. The closed-cell foams normally have higher compressive strength due to their structures. However, closed-cell foams are also in general denser, require more material, and as a consequence are more expensive to produce. The closed cells can be filled with a specialized gas to provide improved insulation. The closed-cell structure foams have higher dimensional stability, low moisture absorption coefficients, and higher strength compared to open-cell-structured foams


Correct. Cutting the foam board will NOT affect its integrity. It's closed cell foam, meaning that each cell or air pocket is seperate from the rest, which is what keeps it from being waterlogged.
 
Swampfox88 said:
You have been super helpful!

One more question for you , if it was your boat would you remove the side panels(going up side of the boat). they are filled with foam, but take up a 3 inchs on each side of boat. Are these necessary or just a result of old design. the entire floor will have foam .

I'd leave it in there, as it provides additional flotation in the event of being swamped.
 

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