RE: A look-for trimaran plans

Discussion in 'Multihulls' started by Liturl_Ellyrod, Jan 2, 2010.

  1. Liturl_Ellyrod
    Joined: Jan 2010
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    Liturl_Ellyrod New Member

    Gentlemen, and what Ladies, Back in about 1968, Popular Mechanics or Popular ??? had a design for a trimaran to be constructed out of plywood, I believe it was 18 0r 20 foot long. Do any of you Sail-heads remember where to find such plans or thoughts where I might find a lead to such plans. Please E-mail me at "" Am anxious to re-create same. Liturl
  2. bill broome
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    bill broome Senior Member

    1. have you been to your library? 40 y.o. magazines are a challenge, but you might get lucky.

    2. email 'pop mechanics', they will have a record, or maybe can re-direct you.

    3. likely to be an early piver design. here's a 17' model:

    good luck!
  3. kaamaman
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    kaamaman Junior Member

  4. marker
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    marker Junior Member

    Last edited: Jan 2, 2010
  5. rayaldridge
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    rayaldridge Senior Member

    Better yet, this one is a Tchetchet design. He was a better designer than Piver, I think, but not the salesman Piver was.
  6. themanshed
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    themanshed Senior Member

    This boat was designed to be built from 3-4 mm plywood. I'm using Carbon / Foam on mine and had the hull shape re-designed designed. The 3-D picture is the stock plan from wood.

    Attached Files:

  7. magwas
    Joined: Oct 2009
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    magwas Senior Member

    Here is the main hull. Just the block, no cockpit, centerboard and such. Deck is simplified because (1) no offset data has been given to calculate the bend and (2) with that bend the deck would not be developable. The zip contains
    - an openoffice spreadsheet of offsets aquired from the article, and the actual coordinates computed. Beware that in my language version the decimal point is a comma!
    - a python script which converts the ':'-delimited csv export of the above to a form which can be imported to freeship. usage (run it without arguments for help, or see the source):
    ./ tri.offsets2.csv : 7 1 4 >mainhull.chines.txt
    This two should also help to come up with pontoons and cockpit. If I were to build it, I would proceed with them and use freeship to bring it together and add details, compute plate development and build it stitch&glue (or origami if I would feel like being an iron man).

    There is a jpeg image of the hull *developability check mode), and a freeship file of it. The bow is extrapolated from the offset data in a way that the hull remained developable.

    I wonder what would be the plate thickness if one wanted to build it stitch&glue?

    Attached Files:

  8. magwas
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    magwas Senior Member

    I have digitized the pontoons as well.

    A picture, a freeship model and the offsets table is attached.

    I have trimmed the top of the pontoon to be linear, as it was rather bumpy after import, and designed a developable bow.

    What could be the reason behind flat bottom? Smaller wetted surface, or just to make it easier to build?

    Attached Files:

  9. ThomD
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    ThomD Senior Member

    "He was a better designer than Piver, I think, but not the salesman Piver was"

    Seriously, what makes you think that. Piver boats are still in happy hands to this day. Piver himself had many impressive early voyages in his own boats when doing that stuff was a lot more avant guard than today. Broadly, his ideas dominated the field for several decades. We don't entirely know what his boats would have been like if he had been able to sell them. He was enamoured with strip hulls and rounded shapes, but the market wanted plywood, at least at the scale he was able to address. Sure he oversold, but most of the better known names of the time did also, he just bought ink by the truckload as the old saying goes.

    Comparatively, all I know about Thetchet is pretty much a footnote, though earlier still than Piver.
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