Small trimarans under 20'

Discussion in 'Multihulls' started by Doug Lord, Jun 24, 2012.

  1. patzefran
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    patzefran patzefran

    I agree, on my Strike 15 I used 3.5 m x 80 mm OD carbon pipes as beams (I got them at 20 Euros /kg !). I got also a broken carbon A cat mast shortened to 8 m, a carbon rudder also from an A cat.
    I use also carbon tangs (much lighter than stainless steel !) for the (vectran) waterstays and UD stripes for some local reinforcement on the main bulkheads. Otherwise my boat is plywood/glass/epoxy
    sheated with glass on the bottom. No need high engineering (altough I used to be one) and a lot of money to get a lighter / stiffer boat.
     
  2. upchurchmr
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    upchurchmr Senior Member

    The major benefit is that you went to 90 mm.
    Carbon helps but the stiffness of the actual material is about the same, Depending upon the layup.
     
  3. upchurchmr
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    upchurchmr Senior Member

    Patzefan,

    Are the carbon tangs "bent" between the attachment to the boat and to the waterstay?
    If so watch them very carefully.
    Early Tornado use of carbon in the attachment of the beams to the boat tried carbon, but they delaminated fairly often.
     
  4. patzefran
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    patzefran patzefran

    The tangs are in line with the loads and they hold for 5 years now. The beams were industrially built by Epsilon composite using adequate wrapping
    they are 30 % lighter and much stiffer than equivalent thickness aluminium tube. As for the mast, having using carbon mast for 10 years now
    It is a fact they are much better (near 40 % lighter, stiffer) than aluminium ones, using of course adequate wrapping and bonding process.
     
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  5. upchurchmr
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    upchurchmr Senior Member

    In line is good, probably the best, easiest use of carbon.
    Sounds like the beams and mast were professionally designed and built, even if you did not do the design yourself.
     
  6. patzefran
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    patzefran patzefran

    Of course, it is the case. But even for professional, it is difficult to benefit of the high properties of carbon if hand layed in a laminate.
    From Handrew C. Marshall, Composite Basics :
    "Hand laid carbon fiber rarely exceed 50,000 psi tensile or 40,000 compressive strength. Prepreg can be little better unless tooling is used to insure straightness and low resin content. However, pultruded material may exhibit 4 to 8 times these figure"
     
  7. redreuben
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    redreuben redreuben

    And so I have to ask, what are the strength equivalents of hand laid glass ?

    Was Marshall's resin polyester, vinylester or epoxy ? Because if its polyester the comparison is pointless, the 20 cent resin will explode long before the carbon shows its benefits.

    You can rattle on like a stone in a hubcap for days about what materials are better on boats but unless you define the requirements and compare like with like it's all rather pointless in a broad sense as boats are such a homologation of compromises saying "a" material is useless compared to "b" is just choosing sides for the sake of it.
    People prattle on about kevlar's abrasive resistance and ability to resist punctures, it's all bollocks with cheap resin on the wrong side of an inappropriate core material !
    And, AND, the cloth is extremely hydroscopic, but....... on the bottom of a canoe which you can dry out and repair easily it's great !
     
  8. patzefran
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    patzefran patzefran

    The values are for Vinylester or Epoxy . For allowable tension and compression, Marshall says with unidirectional carbon laminate :
    same as E-glass at low end, add 80 % at high end. He says these value are only a first guess guide, real values depends on specific resin system an process, like you.
    IMHO, main advantage of carbon is stiffness (Young modulus), when properly used. Using same resin and process as Glass laminate, Carbon is stiffer and a little lighter.
     
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  9. Doug Lord
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    Doug Lord Flight Ready

    EXOCET 19 by Perspective design is still being developed. I first found out about it in 2015 and as of today their Facebook page says "work continues". They have published a price though: 39,700 Euros!

    Exocet 19 foiler trimaran.png
     
  10. upchurchmr
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    upchurchmr Senior Member

    Pretty illustrations mean nothing, but that price means I don't care.
     
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  11. Doug Lord
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    Doug Lord Flight Ready

    I don't know- from when I first saw the Exocet in 2015, I thought the technical aspects were interesting-and I still do. It seems all prices are ludicrous these days-I think a new 18'DNA costs about this much or more. Both are all carbon but the only one available is the cat-too bad. I'm looking forward to the day that a high performance all carbon foiling tri under 20' hits the market-a technical and performance milestone if its done right....
    The F101 is cool but doesn't use all the advantages a tri platform has to offer.
     
  12. Corley
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    Corley epoxy coated

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  13. Doug Lord
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    Doug Lord Flight Ready

    Great-thanks , Corely! Even if you don't have facebook, if you click on the video and then hurry-up and click on the fullscreen icon(two diagonal arrows on lower right side) they won't cut you off.....
     
  14. waynemarlow
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    waynemarlow Senior Member

    [​IMG]

    A fun little 16ft Tri I'm playing with, basically 1 hull from my old F16 and a cut down A class main and mast that had been damaged at the base. A few niggles to get it sorted but do like the ability of getting back on after a capsize on the low floats as I have hurt my rotator cuff in my shoulder and finding it difficult to get back on the cats I'm normally on.
     
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  15. waynemarlow
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    waynemarlow Senior Member

    bitsa 5 rear.jpg

    And from the rear
     
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