International Canoe hull design

Discussion in 'Sailboats' started by Steve Clark, Dec 13, 2011.

  1. gggGuest
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    gggGuest ...

    I dunno, I would say that there is more scope for moderate skilled builders in foam/carbon than there is in plywood. The exotics are much more forgiving in that you can spot something that's not quite right and reinforce or otherwise sort it so much more easily. The trouble with foam carbon isn't skill so much as the finishing work and all the dust (I hate the dust) and stuff. You don't need to go vac bag/all the stuff to build a epoxy/foam boat, but a hand layup boat will be a bit heavier, probably about the same as a ply one. Its awfully depressing if you look at say Chris Maas' workmanship and think, I could never do that. Well I for one can't. But I can get close enough to get an operational boat. Maybe its not quite trick enough to win a worlds, but the chances of it doing that with me steering are exactly zero anyway so what does it matter?

    You certainly don't need female moulds and all that sort of thing... I really think you are overcooking the problems... You build a male jig from mdf or something formers and strips and fair that. It doesn't even need a continuous surface if you aren't vacuum bagging. Then you just add and take away stuff until its as close to fair as your patience will stand.

    Someone who can build a decent boat in plywood will easily build a decent boat in foam epoxy, but of course it always helps if there's a mate you can touch base with for skills transfer. The Cherub class in th UK have a great idea of what they call "sticky weekends". Someone with a reasonable sized workshop declares open house for a weekend, and people gather, some with projects of various sizes. They experienced people provide skills transfer, the people with projects get help, and the people who are new to all this look and learn. Social session on the Saturday night: beer and a curry, and so the skills move on...
     
  2. BobBill
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    BobBill Senior Member

    Foam Based Carbon Hull

    Fascinating material. One interesting note, with all that carbon, the mast appears carbon and boom too? It would seem logical.

    At first I thought boom was metal.
     
    Last edited: Dec 17, 2011
  3. BobBill
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    BobBill Senior Member

    Foam Based Carbon Hull

    Very informative.

    Have question. Appears to be foam carbon layup...


    Foam on the stations, carbon atop...likely two layers and foam removed to fair? Not sure how that works...would not foam sag a bit?
     
  4. gggGuest
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    gggGuest ...

    constructional foam is pretty stiff... Dont get me wrong, even if you are doing wet layup over battens you have plenty of battens, but its fairly rigid stuff: 8mm foam is, I guess, not noticeably more floppy than 3mm plywood.

    In fact I should think that the biggest argument for having loads of battens is going to be to make it easier to squeggee and roller down your wet layup...
     
  5. Doug Lord
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    Doug Lord Flight Ready

    ----------------
    Corecell bead and cove planks are 5lb/cu' as opposed to 1-2lb/cu' for EPS/ styro- so considerably stiffer.


    another method: http://www.f-boat.com/pages/construction/index.html

    Corecell bead and cove planks and corecelll sheets: http://www.noahsmarine.com/United_S...S/ATC_Chemicals-US/body_atc_chemicals-us.html
     
  6. Steve Clark
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    Steve Clark Charged Particle

    hull fixture.jpg
    Hull fixture for building Gaijin.
    Lots of stations to keep it fair, lots of holes to keep it light.
    Probably not cheap, but what about doing it well ever is.
    Top flange is correct for the changing bevel of the deck, so you build the whole boat in the jig.

    deck fixture.jpg
    For building the cone shaped foredeck.
    Probably can be done another way, but this will be the right shape.

    Laminate would be 200 g/m^2 carbon on either side of 6mm foam. Doublers and patches top taste.
    SHC
     
  7. BobBill
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    BobBill Senior Member


    So the foam goes down, then glass/resin, vacuum or squished, sealed and cured...lifted and reinforced etc...

    Sounds simple enough...
     
  8. BobBill
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    BobBill Senior Member

    And, gggGuest and Doug thanks.

    Great stuff. With my project, have to decide between thin Okuma later glassed vs sheets or the foam/layup. Good foam sources too. Merci.
     
  9. BobBill
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    BobBill Senior Member

    Foam Based Carbon Hull

    The choice before me has been on my mind for a couple days:

    Am amateur when it comes to forming hull with carbon, wood is different story, however.

    So, as I see it, building a hull (in this case a Malibu Outrigger_which has but three stations, outside of bow and stern)

    In wood, using thin ply to accommodate final glass sheath...which is basic and simple. Hard chine dory shape hull, no round anywhere...

    Or, if I have it right,

    Set up the stations in place, but reduce size to accommodate foam and glass/carbon hull, and fair foam and do layup, then install full sized bulkheads when hull is separated.

    The above includes foam cuts to accommodate bottom stems and top stems

    Maybe couple stem/stern strips to stiffen for hand layup.

    Is that about right for this job? Idea of full strip hull form seems unnecessary for this simple dory shape, to me.

    Beat me up, please, where I need it.
     
  10. DCockey
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    DCockey Senior Member

    What design is a "simple dory shape"? Certainly not Steve's IC design.
     
    Last edited: Dec 30, 2011
  11. BobBill
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    BobBill Senior Member

    Foam Based Carbon Hull

    Mentioned the Malibu Outrigger, to find out if I can do as indicated, instead of wood, as the IC build seems to parallel my intentions, but is more sophisticated...
     
  12. Ilan Voyager
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    Ilan Voyager Senior Member

    Thanks for the Lindahl's link. Lindahl has a very long experience (more than 30 years) in catamarans. The pics are very explicit and the method is rather simple, not high tech but the results are truly very good. That shows that in small boats it's not necessary to go to complex methods, but to use at its best a good simple method. That asks for a lot of care and craftmanship.

    The short videos in You Tube show that the class A LR4 has a very good potential. Nice design.

    In small boats at unity, using too much technology ( CAD CNC infusion vacuum and tutti quanti) do not help for building faster, nor to obtain truly better results but surely hurts and bleeds the wallet... In serial building it's another matter. But often when I see the final products I have the feeling that all these technics were more for the marketing. For big boats all these technics are mandatory simply because any gain on such "big" structure is worth to obtain. That's also pretty expensive and sailing is loosing people, the boats are truly out of reach for low medium income people, or for DIY. You could make a competitive class A in garage 20 years ago, now it's impossible.
     
  13. BobBill
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    BobBill Senior Member

    CutOnce got me thinking I can do this in garage, and have to be sure. is all. MO is not complicated like that slick boat Clark put up, but still worried about details of project. No hijack intended, process is the concern.


    That aside, I believe Voyager makes a good point.
     
  14. DCockey
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    DCockey Senior Member

    BobBill, have you considered starting your own thread about your questions on your project?
     

  15. BobBill
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    BobBill Senior Member

    International Canoe Design

    Yes. Was only after process info, and should have done it, but the material here was fascinating and forgot about it, especially the Lindahl site link and the F boat link Doug provided. Really, did not want to change this thread's direction.

    Sorry. But I learned much here.
     
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