My Design - Trifoglio 25' - Suggestions & Opinions

Discussion in 'Sailboats' started by DVV, Nov 20, 2020.

  1. Doug Halsey
    Joined: Feb 2007
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    Location: California, USA

    Doug Halsey Senior Member

    Sure. Those photos I posted are all Moths (11' long). But I don't see anything wrong with larger ones (the ones with higher freeboard anyway). Here's a 20' scow that my uncle built & sailed frequently in the 1940's.
    As noted in other posts, scows are at their best when planing (usually not close-hauled), but many scows still perform nicely going to windward.
    I don't understand what you mean by this, but I don't think scows are any more difficult to sail than skiffs, generally speaking.
     
  2. cracked_ribs
    Joined: Nov 2018
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    cracked_ribs Junior Member

    Pretty amazing that he built that in the 1940s. I would have guessed a few decades later, just because the overwhelming impression is that someone said "hey, what do you want to do with the Volvo 240 that has no engine or running gear?" and he responded, "well, there are vehicles that run without motors...how are we set for sailcloth?"
     
  3. Doug Halsey
    Joined: Feb 2007
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    Doug Halsey Senior Member

    I've got absolutely no clue what you're saying.

    But, nevermind, I did some more digging into family history and it looks like he built the boat in 1939.
     
  4. cracked_ribs
    Joined: Nov 2018
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    Location: Republic of Vancouver Island

    cracked_ribs Junior Member

    It's just funny that this unique boat of 1939 looks so much like a 1980 sedan.

    It must have seemed incredibly futuristic at the time.
     
  5. DVV
    Joined: Nov 2020
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    Location: Italy

    DVV Junior Member

    This is a Colvin design, quite extreme, but I like it. Based on an old chinese junk (hanshaw bay fisher/trader). The bottom side of the bow seems to be curved (sides lower than center)

    zimage_0024.jpeg d3bb42bc1346a4234520ee26537c1d98.jpg
     
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  6. DVV
    Joined: Nov 2020
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    Location: Italy

    DVV Junior Member

    Update:
    Lots of work done. Added details, added dimensions and offsets.
    Almost ready to start building the balsa model, just need to design a Jig to use.
    Here some details of the internal structure.

    DVV Schermata 2020-12-18 alle 17.17.39.png Schermata 2020-12-18 alle 17.19.02.png
     
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  7. DVV
    Joined: Nov 2020
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    Location: Italy

    DVV Junior Member

    Schermata 2020-12-18 alle 17.58.53.png
     
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  8. gonzo
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    gonzo Senior Member

    Is 20 degrees where you have the highest righting moment or where you don't have any more positive stability?
     
  9. DVV
    Joined: Nov 2020
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    Location: Italy

    DVV Junior Member

    I hope that's where I have the highest righting moment. If it was where I dont have any more positive stability I'm afraid I would capsize the boat just by jumping into her! :)

    Anyway, it was wrong. Max GZ is at 40°, and AVS 126°.

    Maximal GZ : 0.686 m
    Heeling angle for GZ maximum : 40.0 degr
    Heeling angle at which righting lever=0 again : 126.2 degr

    I'm afraid that's a bit too much, I think I'll have to go back to add some weight or depth to the keel...

    EDIT: No. I think I over reacted. 40° is quite fine, I dont think I need to modify any keel, its fine like this.
     
  10. DVV
    Joined: Nov 2020
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    Location: Italy

    DVV Junior Member

    Hello everyone. An update about the design.

    Many things changed again. At the end I have been able to workout a single chine version that seems fine to me.
    Moreover, there is no more keel, I switched to an internal ballast with leeboards. I used a bigger cabin top, and this gives me standing headroom inside, and enough buoyancy to compensate to the missing keel. Stability Curves are still fine, with an AVS of 130°. Max GZ is now at 20°, so she will be quite stiff, but I think I can live with that.
    She's may be a bit less good looking, but that's not my main driver. The objective is to build the boat, so the simpler the better.

    DVV
    Schermata 2021-01-28 alle 19.42.21.png
     
  11. Dolfiman
    Joined: Aug 2017
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    Location: France

    Dolfiman Senior Member

    Your project reminds me of the Caragogne, a 4,6 m with small cabin sailboat with such "tender like" shape and bow. The cabin version itself derived from the popular Caravelle used by a lot of sailing schools in France since the 60's and still a very active class. Here photos of a Caragogne recently refit (in 2019) and a video of sailing in costal waters. As long as the waves are moderated, the bow does not prevent an easy sailing including upwind :
    Mise à l'eau de la Caragogne (amarrage-asso.fr)
    Les abers en caragogne - YouTube
     
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  12. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    It should be noted the beautiful boat you linked does not appear to have standing headroom.

    It was cruising along quite well I'd say.
     
  13. ExileMoon
    Joined: Oct 2009
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    Location: Shanghai

    ExileMoon Junior Member

    I think we should consider the design of this boat based on actual needs.

    For example, if you are just trying to get a houseboat floating on the water under your limited budget, then you don't have to think too much about things that deviate from habitability such as 2% faster.
     

  14. DVV
    Joined: Nov 2020
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    Location: Italy

    DVV Junior Member

    Beautiful vessel!
     
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