To do or not to do... All glass stringers

Discussion in 'Materials' started by JamesR, Oct 26, 2004.

  1. JamesR

    JamesR Guest

    It was suggested to me that I use only solid layup of glass in the stringers of the motorsailer Im going to build. No core at all. I thought the stringers needed something for stiffness. Any thoughts on this??
  2. Herman
    Joined: Oct 2004
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    Location: The Netherlands

    Herman Senior Member

    This idea came from your glass supplier, I presume?

    When bending a stringer, or a stick, the top will get larger, the bottom will get shorter. Somewhere in the middle, there is a line which does not get shorter, nor gets longer. This is the "Neutral Line". This line bears no load.

    The glass that will go in the middle, will carry no load as well. Therefore, stiffness-wise, it is best to create a structure, where the load bearing material is as far outside as possible. In the middle can be something that needs to keep the load bearing layers spaced from each other. This is the task of the foam.

    This is the basic principle. Of course it can be refined with more text and explanation, this is very basic.

    Unless there is a good reason, I do not see why to do something else.

    Good reasons may include:
    -required space
    -amount of stiffness wanted
  3. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Good point Herman, I too thought the same of whom ever is selling him gassing materials. Solid core stringers will provide little more strength, but considerable weight and effort. I would consult the designer or other builders of the design (though, take their advise with a grain of salt, they aren't designers) and see if this is an issue that has come up before. The designer may have a set of scantlings for severe service, which may cover beefier stringers and a host of other areas you may have over looked in the effort to stiffen things up (if this was your intent, by using solid stringers)
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