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Balsa cored hulls

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Old 04-26-2008, 05:10 PM
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Default Balsa cored hulls

Are a lot of hulls cored w/ end grain balsa? If the outer layer of glass is compromised, wouldn't the balsa get waterlogged and if so is the boat junk or just heavier?
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Old 04-26-2008, 07:42 PM
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Compromised?
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Old 04-26-2008, 08:04 PM
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Originally Posted by fobes View Post
Are a lot of hulls cored w/ end grain balsa? If the outer layer of glass is compromised, wouldn't the balsa get waterlogged and if so is the boat junk or just heavier?

Only in the affected area, it would not migrate at all !! THAT is unless there was a "Shop related problem" with the core bonding/bedding.

One of my military boats a (balsa cored) 12 M Cat ran up a rock breakwater in the fog and was completely out of the water at that, it was pulled off by a tug and towed back to the base where I picked it up later that day.

The only water to be found was under the missing outside laminate ; we simply removed/replaced those small areas and reglassed the bottom.

Easy repair BTW

Last edited by Steve 1; 04-26-2008 at 08:13 PM.
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Old 04-26-2008, 08:34 PM
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the boat will be hevier, but the more important issue is the integrity of the hull itself. depending on how much water and how large an area it may in fact be junk. also depends on how long the core has been saturated, because the water will spread and attract moisture especially if the boat has a full cover or remains dormant for lengths of time.
a good way to check is with a moisture meter and then try covering the boat completely and leave a dehumidifier in it for a week or two. after a couple days check to see how much water it colected.
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Old 04-26-2008, 09:05 PM
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Water will not spread across balsa. Do a test! Take a piece of balsa about 12 inches long and submerse about 3 inches in water and it will not travel up.
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Old 04-26-2008, 09:31 PM
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Some of the core in the deck of my challenger was rotten from where they didnt seal the bolts for the lifeline. It was all in a 6 inch radius of the wholes and i cut the first layer of glass out with a die-grinder then dug the balsa out.Replacing it was a few layers of mat.
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Old 04-26-2008, 11:50 PM
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By compromised I mean that if you got say a pinhole (or more) through the outer layer of glass and water could get into the core would the balsa act as a sponge and soak up water to saturation thereby ruining the integrity of the hull. I thought the water would migrate through all the wood. There must be many different manufacturers that core with balsa and a boat that was maybe 20 years old would see its share of dock rash/bottom scrapings that could allow water intrusion.
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Old 04-27-2008, 12:44 AM
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No, it barely gets bigger than the damaged area.
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Old 04-27-2008, 03:39 AM
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If it is in an area that saw high water pressure from being at a planing speed, then the core can get "hydrauliced" and lose it's bond and seperate from the hull.
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Old 04-27-2008, 08:32 AM
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I've taken soaked, rotten balsa out of more than a few boats. Not just small spots either.

Go down to the Skater forum and read about their balsa woes. From what I understand, their problem is that the insides of the hulls aren't painted and laying water soaks into the coring thru the inside layup.

Balsa is one of a few woods with a closed cellular structure. So is white oak- that's why it was used for years as structural members in wooden boats. Most woods cave a cellular structure that looks like lots of miniature straws. Closed-cell woods have a similar structure but each cell is short and the "straw" tapers to a closed end. This keeps them from absorbing water through the "straws"

These woods resist rot, they're not rot-proof.
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