Floatation

Discussion in 'Boat Design' started by KenO, Jun 12, 2018.

  1. KenO
    Joined: Jun 2018
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    Location: Alabama

    KenO New Member

    I have a 22' Starcraft, Deep V, Center Console, Aluminum, and Riveted. Boat has been on a fresh water lake but I will use it in salt water. In process of restoration. Removed everything including the floor and the foam. The foam was wet on top and had trapped water underneath. I cannot take the chance of trapping salt water. I did have the outside bottom epoxied and painted and put two coats of epoxy on the inside. I do not want to use expanding foam under the deck so what should I use?...Pool Noodles? Life Jackets, a couple of Beach Rollers?
     
  2. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    Was there corrosion on the inside bottom, where water had got between the foam and the hull ? Was the hull inside painted before the foam was installed, originally ? A good paint job takes away a lot of the terrors of poultice corrosion, which can bedevil alloy in contact with foam. Ideally you don't want foam in an alloy boat, that can't be removed reasonably easily, because if it is a permanent fixture, welding repairs become a fire risk. Your options appear to be polystyrene, best coated with a latex paint, or flexible polyethylene foam, which is a bit expensive.
     
  3. KenO
    Joined: Jun 2018
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    Location: Alabama

    KenO New Member

    Thank you, there was no paint on the inside bottom. There was no corrosion I guess since the boat was only in fresh water. I will check out the two foam materials that you suggested. I believe pool noodles are made from polyethylene but will find this material in a more solid form as compaired to a pool noodle. Thank you.
     
  4. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    Don't laugh, but plastic drink bottles are the choice of some, as buoyancy, but of course even when carefully packed, still leave a fair bit of the volume not doing the job. Better than nothing though, I cringe when I hear stories of boats that sank like a stone, and only an epirb and a prompt rescue effort saved the occupants.
     
  5. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    Sounds like a happy enough ending to me.
     
  6. Ike
    Joined: Apr 2006
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    Location: Washington

    Ike Senior Member

    OR, you good use polystyrene insulation foam, wrap it in vinyl plastic and seal it up so water can't get to it. Home Depot, Lowes, and other hardware outlets sell Polystyrene Insulation foam in sheets, 2" thick by 2 ft by 8 feet. This is not styrofoam. Styrofoam is a brand name, usually white and has much bigger foam bubbles and is easily damaged. Polystyrene insulation foam is generally pink, or blue depending on brand. It's relatively cheap, has much smaller cells and is 2 lb density (1 cubic foot weighs two pounds) Cut it to the size and shape you need, Get some heavy duty vinyl plastic (probably at the same place) Wrap the foam and seal it with a good packing tape. see here how I did this on my SeaRay.
    Boat Building Projects | 1972 Sea Ray 190 Rebuild http://newboatbuilders.com/pages/SeaRay190.html
    Ten years now and no problems. The problems with polystyrene? Polystyrene is affected by most petroleum products and a lot of cleaners. So you have to protect it. The vinyl does double duty. It keeps the water out as well as any spilled oils, gas , bilge cleaners and so on. It is 2 lb density foam so calculating how much is needed is simple. But in this case I don't think you need to do that. Just fill the space where the blown foam was. Pool noodles (polyurethylene foam) will work but cost you a lot more. Bottles are good as long as they are sealed so water can't get into them, but it takes a lot of bottles. There are other solutions, but in many years of advising boat builders on how to install foam flotation this is the best and least costly solution.
     
  7. KenO
    Joined: Jun 2018
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    Location: Alabama

    KenO New Member

    This sounds great and I will start on out this week. Thank you!
     
  8. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    I wonder whether sound kind of device to weld Ike's plastic sheet sealed watertight, might be a good idea, certainly fuel can make an awful mess of PS foam, and tape might let go in places.
     

  9. Ike
    Joined: Apr 2006
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    Location: Washington

    Ike Senior Member

    I had the same thoughts. So what I did was make sure the seams were double overlapped and always on top. By double overlapped I mean folded back over themselves.
     
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