New Designs

Fiber Orientation

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By now every boat builder knows that fiber orientation is critical to laminate strength.  And I’m sure everybody knows that 34 oz triaxial for example has a bending strength of some 65,000 psi in the 0 degree, and about 20,000 psi in the 90 degree orientation, hand layup. And unidirectional fabric will have some 100,000 psi bending in the 0 degree and maybe 3,000 psi in the 90 degree.

But that is not all there is to it.  There has to be off axis fiber even if it performs less well.  I first learned about that in Tsai’s composites class in ’90 I think it was.  In tension it would not matter, but in compression and bending, the hard-working 0 degree fibers have to be kept in column, as it were.  The trick is to  have no more than 3 zero degree layers stacked before adding an off axis one.  Then you can add three more.

I have visited mulithull build sites where I have seen plans from famous designers with like, 10 or 20 layers of 0 degree stacked up, and no off axis fibers.  Don’t they know?  And they charge many times what I do.

New Designs

Was Out Much of This Week

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I had rare good weather to mix epoxy. Supposed to rain next week so will be back in. I have thought of many topics for here for the coming week.
Fiber orientation update
Fiber mix examples
Taking a mast joint apart
Upgrading bad details from other designs
Psychology and window shapes

See, I think when I am stirring epoxy.

New Designs

Skype and Big Files

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Prospective customer Anton showed me that Skype can be used to send big files without setting up an FTP site. Lets try if someone wants the e-catalog, or composite construction manual or the CM construction manual. I will look into the DVD later as it is so much bigger. $25 for each? I will get something set up on the website. For now just use cards? For now I would rather not use Paypal.  My Skype is khughes.multihulldesigns
Hit me and I can send files back via Skype.