Freeze Dried Boat

Discussion in 'Boatbuilding' started by quickenberger, Dec 19, 2016.

  1. quickenberger
    Joined: Oct 2016
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    quickenberger New Member

    I recently picked up a Boston Whaler project boat that will most likely have some water in the foam. I knew this going into the project as well as anticipate a possibly rotten transom.
    That leads me to an idea where if I apply some composites experience with physics then maybe I won't have to manually dig the foam out...

    We all know water boils under vacuum, like freeze dried food, so why not apply the similar process to the entire hull?
    Making sure to not have any cavities that may be crushed under vacuum what if I make a vacuum bag around the boat with all of the hatches, consoles, wiring, etc removed, and pulled it under vacuum? There would have to be breather to allow the water vapor a path to escape but that is pretty easy. The vacuum process may take over a week but it would be interesting to see if it would work. Some holes may need to be drilled to allow the water vapor a path to escape but has anyone tried or considered this before?
    I have seen people use shop vac's to pull water out of the hull, but boiling the water out under vacuum would be far superior to this I think.
     
  2. ondarvr
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    ondarvr Senior Member

    Removing the water (moisture) isn't a huge problem, the way you suggested will work, and companies do market that method for repairs, but.....

    The real problem is that for the foam to absorb water it has normally degraded to the point where it more resembles open cell foam than the closed cell product that was originally sprayed or injected into the hull. Since open cell foam is commonly referred to as a sponge, it may not be the best product for use in a hull.

    So even if you remove 100% of the water, it will suck it back up almost as fast as you removed it.

    This means you still need to remove it for the repair to be of much value.
     
  3. quickenberger
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    quickenberger New Member

    I agree that the foam degradation results in the water returning into the foam. That being said, if the issues of the water getting into the foam are fixed correctly, then water should not get in there after water removal. I have never liked the idea of water being in contact with the expanding foam and it should not be. There should be some physical barrier keeping the water out, i.e foam is injected or installed then hull bonded and sealed where water cannot get in.
    This is probably more theory than reality, but I will see how the BW looks when I get it here and get it thawed out!!
     
  4. ondarvr
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    ondarvr Senior Member

    Watertight on a boat typically means once water gets in it will never get out. There aren’t many places in a hull that can easily be kept dry, and while there could be huge improvements in products and design, people just don’t want to pay for it.
     
  5. quickenberger
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    quickenberger New Member

    That makes sense. In theory it could work. In practice, I will let other's experience speak. Seems like I'm going to have to bite the bullet and get sweaty!!
     

  6. Ike
    Joined: Apr 2006
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    Ike Senior Member

    The problem isn't the water, the problem is the foam. If the foam has been water saturated for years then the foam is degraded. It no longer maintains it's structural integrity. In a Boston Whaler the foam is not just for flotation. It is a vital structural element which gives the hull it's strength. We are not talking about 2 lb density foam used for flotation. This is much heavier. If my memory serves it is 6 lb density. (could be higher) So Even if you get the water out you still have a problem and the foam needs to be replaced, which on a BW means separating the hull and liner.
     
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