Fill inner hull w/foam?

roscozen

roscozen

Petty Officer 3rd Class
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Mar 8, 2008
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I have a 1959 glasspar seafair sedan.

This boat came with an inner hull for flotation. It has a drain plug below the transom and an access flush plug on the floor just inside the cabin.

So I am wondering how practical it would be to fill that area with a pour-in or pump-in flotation foam.

The deck is glassed in and in great shape, but i noticed i have to drain that inner hull (bilge) from time to time.
I suspect somewhere on deck there must be a crack allowing wash down water and occasional rain in.
Since i just scoured every bit of the deck just prior to new carpet and all was sound, the only area that could have an opening is under the splashwell where it would be practically impossible to do a repair.

any thoughts on foam?
 
C

Capt'n Chris

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Re: Fill inner hull w/foam?

Is it your intention to fill a blind cavity with it? The cavity would be the hidden stringer system beneath the sole. Have you opened it up (cut out the sole?) to see what is in there...rot? Water?
 
H

Haffiman

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Re: Fill inner hull w/foam?

If already a known leakage and then try to fill with foam?
Closed cells or not, but in my opinion a bad idea.
Without knowing the volumes of cavities to be filled, you will not be able to calculate the amount of mix to be injected.
 
Bondo

Bondo

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Re: Fill inner hull w/foam?

The deck is glassed in and in great shape, but i noticed i have to drain that inner hull (bilge) from time to time.
Click to expand...

Ayuh,... The Reason it's in Great shape is because there's No foam holding the water in, rotting it out...

I'd leave it alone, 'n continue to drain it regularly...
 
Bob's Garage

Bob's Garage

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Re: Fill inner hull w/foam?

What hasn't been addressed is the expansion power of the foam if you were to proceed with your proposal. You could easily "blow out" the hull, deck or both with the expanding foam. It is very powerful stuff and relentless about expanding once mixed.

The only safe way to do it would be to cut access holes and expansion holes in the deck about every 12" or so. The foam does not flow very far before chemical reaction begins and that is the reason you will need many holes.

Your best course of action is to find the leak. It could also be at the bonding joint between the inner and outer hull. Of course, if the water gets in while just sitting in the water, then the leak would likely be under the water line.
 
C

Capt'n Chris

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Re: Fill inner hull w/foam?

Bob's Garage said:
What hasn't been addressed is the expansion power of the foam if you were to proceed with your proposal. You could easily "blow out" the hull, deck or both with the expanding foam. It is very powerful stuff and relentless about expanding once mixed.

The only safe way to do it would be to cut access holes and expansion holes in the deck about every 12" or so. The foam does not flow very far before chemical reaction begins and that is the reason you will need many holes.

Your best course of action is to find the leak. It could also be at the bonding joint between the inner and outer hull. Of course, if the water gets in while just sitting in the water, then the leak would likely be under the water line.
Click to expand...
How funny, I was awaiting his response before I brought that up.
 
roscozen

roscozen

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Re: Fill inner hull w/foam?

Capt'n Chris said:
How funny, I was awaiting his response before I brought that up.
Click to expand...

ok, I'm getting the feeling that if the inner hull is not a totally glassed in void, and there's exposed wood in there, then filling it w/foam would lock in rot.
I'm pretty sure the water buildup comes from the topside of the deck.

on days when i've had the boat out, even in rough chop, i've taken out the plug and tilted the boat up on the trailer at a 45 deg. angle and not a drop came out .

so the water must be coming from the deck under the splashwell where i don't have access. hose down water, rain days when i haven't had the cover on, etc.
after researching the dynamics of filling the void w/foam, i see that i'll have to open up the deck and fill from the openings if i want to ensure a complete fill without blowing the deck out.
i know the pressure of that stuff will likely push out any weak spots and that would certainly be a big mess to have to deal with, not to mention the issue of locking in moisture.
ideally, the only way i could proceed with this is if i filled the void with tiny lightweight balls filled with air. that would still allow any moisture to drain out and yet retain the buoyancy i'm looking for. i really don't know that they exist, tho.

i think i'll leave it alone for now till a clearer solution presents itself.

thanks, guys, for all the input.
 
Hoggar

Hoggar

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Re: Fill inner hull w/foam?

The best Idea would be to find and fix the leak weather its in side or out
of the boat its still letting water where it dosnt belong and will eventually
cause expensive problems. Fix it right or get it to some one who can.
 
Bondo

Bondo

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Re: Fill inner hull w/foam?

ideally, the only way i could proceed with this is if i filled the void with tiny lightweight balls filled with air. that would still allow any moisture to drain out and yet retain the buoyancy i'm looking for. i really don't know that they exist, tho.
Click to expand...

Ayuh,... Sounds like we're back to Ping-pong Balls....
 
proaudioguy

proaudioguy

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Re: Fill inner hull w/foam?

Bond-o said:
Ayuh,... Sounds like we're back to Ping-pong Balls....
Click to expand...

Who is Ayuh you open every single post to? Looked him up and he doesn't have an account here that I can find.
 
R

reelfishin

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Messages
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Re: Fill inner hull w/foam?

I redid a 1962 Glasspar deck and stringers about two years ago, the model was a Tacoma. It used a wood deck covered in glass mat and resin, with a wood under structure, and no foam other than a huge chunk added under the bow deck just ahead of the dashboard.

Places to look at for leaks will be seat mounting bolts or screws, leaking drain tubes or plugs, and look very close at the transom, on mine it was taking on water through a poorly sealed set of motor bolt holes and some old screw holes on the transom. The lower transom was rotted as well. Water seeped in around the drain plug tube, and around other hardware right into the lower hull. I redid the transom, floor and stringers all with epoxy, plus when I made the deck, I epoxied in stainless steel studs to hold the seats down with. No carpet, no foam was used. I sold the boat but only after getting into several other projects, the new owner repainted it and installed a new helm and Teleflex steering and keeps it in a garage, so my guess is that it'll out last all of us with that kind of treatment.

Those boats were designed to make use of that air space for flotation, if you fill that area with foam and water does get in, you will have no way to get it back out. Foam which is exposed to water for a long period acts like a sponge.

For safety purposes I'd want to find any leaks, if that area isn't airtight, the boat can sink if swamped. In other words, the only fix for that type of hull is to fix the leak into the bilge area. If you want to add foam, do so under the gunwales and under the bow deck in the form of block foam secured hanging from the bow deck. Having the foam up high may help keep the boat upright if it were to get swamped too.
 
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