Foam insulation question

Discussion in 'Boat Yard Basics' started by svasey11, Jun 3, 2011.

  1. svasey11

    svasey11 I Love microskiff.com!

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    I have a question regarding insulation/foam between my hull and the floor of my skiff.  I posted a few months back with a water issue in this area.  I ended up cutting 3 access holes (1 under the center console and 2 under the live well) cleaning out all the old wet insulation and letting it dry out along with fixing the leak.  I then filled this area with non expanding spray foam the kind from home depot.  Since then I have noticed that on days when the water is relatively calm I’m still getting a large amount of movement on the floor.  What I think has happened is I put in the wrong foam insulation.  This is most likely a structural component of my hull. (My opinion) So this is where I stand now, all (85-90%) of the insulation has been removed again.  Is there a company that could spray in the correct kind of foam insulation that would adhere the floor to the hull?  I’m open for all suggestions. [​IMG][/img][​IMG][/img][​IMG][/img][​IMG][/img]
     
  2. cutrunner

    cutrunner Cert. Yamaha technician

    Best bet is to go to a fiberglass shop and get some 2part close cell foam and pump it in the acess points. Btw is that a fin n feather?
     

  3. DuckNut

    DuckNut Brandon, FL

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    There is no question that the foam that was in there is part of the structure. 

    Non-expanding spray foam?  I don't think that I have ever heard of this unless it is an insulation rather than floatation.  The "Great Stuff" spray foam will stick to anything it touches but it is difficult to control its application.  For example: if you drill a hole in the sole and inject this stuff between the sole and hull you can end up with the foam expanding and pushing the floor up and the hull out where you squirted the stuff.  Think of a snake that swollowed an egg.

    You should replace it somehow.  The squirt can may work but I would opt for a different type of foam product that I would be less worried about over expanding.  Because you are not talking about the entire boat but only a small portion I would use 8 or even 10 lb 2 part foam.  Mix it per instruction and pour in the cavity. You should have your boat tilted so the pour can make its way to the bottom of the cavity before expanding. If you leave your boat level and pour it in you will probably end up with air pockets at the top corners of the the void.

    The reason for a higher weight vs. 2 lb is the expansion ratios.  Each different weight uses the same base, it is the catalyst that differs and that catalyst creates volatility when mixed.  The more volatile the mix the lighter the formula.  The lighter the final product the more volatile the mix was and the greater the expansion is and the expansion is what causes problems.  I believe 2 lb foam expands 30 times its size.  If you do not calculate the size of the cavity accurately, you could have issues.  Not to mention you can't control the direction of the expansion other than hope it expands in the direction of least resistance. The higher density will also be more of a structural refit than simply added for flotation.  Finally, the weight difference of the finished product might be 2 or 3 or 4 lbs heavier, its not like adding an extra battery to your little craft.
     
  4. svasey11

    svasey11 I Love microskiff.com!

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    Thanks Ducknut for the response. Yes this was the non-expanding type of great stuff. I don't believe that this foam was the correct type and second it didn't make it to all the areas of the floor, and third over time it didn't adhere enough to hold the floor to the hull. Just to clarify I need this new foam insulation throughout the entire floor. Most of the old wet foam has been removed and the space is dried out. This space is approximately 3/4 inch think. This 2 part foam your speaking of is there a company that your aware of that could inject that foam or is this something your could get at west marine and do myself. I did find a insulation foam thats called Everciat marine 2 part foam but the cost is 100.00 for a very small can. The area is about 2.5 ft by 6 ft x 3/4 of an inch.

    To cut runner you are correct this is a 99 fin and feather with a 25 hp honda. It is the perfect boat for my 10 year old son and I to chase tails in the lagoon.
     
  5. firecat1981

    firecat1981 BBA Counselor

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    I'm not sure if any company can inject the foam, it is usually poured in before bonding the floor. Check out bateau.com, they are in vero beach and sell all kinds of boat building supplies.

    http://boatbuildercentral.com/products.php?cat=56
     
  6. DuckNut

    DuckNut Brandon, FL

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    Is it just in the cockpit area? Because you can't see the flex under the front and rear platforms or does it include these areas?

    Agree with FC on finding someone to spray it (although everything can be had for a price) and plan "B" is a lot more work.
     
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