A new mini

Discussion in 'Sailboats' started by nemo, Feb 23, 2005.

  1. nemo
    Joined: Apr 2002
    Posts: 132
    Likes: 3, Points: 0, Legacy Rep: 137
    Location: GENOA, ITALY

    nemo Naval Architect

    HI,
    I'm working on a new mini (in my free time), and would like to get some comments from this forum.

    http://album.foto.virgilio.it/bluoltremare78/862782


    Some number:
    Draft Amidsh. m1,949
    Displacement kg986
    Draft at FP m1,923
    Draft at AP m1,976
    Draft at LCF m1,956
    Trim (+ve bow down) m-0,053
    WL Length m6,460
    WL Beam m2,163
    Wetted Area m^2 10,328
    Waterpl. Area m^2 8,642
    Prismatic Coeff.0,404
    Block Coeff. 0,035
    Midship Area Coeff. 0,093
    Waterpl. Area Coeff.0,621
    LCB to Amidsh. m 0,569 Aft
    LCF to Amidsh. m 0,763 Aft
    KB m1,841
    KG m1,828
    BMt m2,369
    BML m18,342
    GMt m2,382
    GML m18,355
    KMt m4,211
    KML m 20,184
    Immersion (TPc) tonne/cm0,089
    MTc tonne.m0,028
    RM at 1deg = GMt.Disp.sin(1) kg.m41,004

    Weight of the bulb is 260kg, sail area is: main:30m^2, jib:12m^2
    Now I'm designing the rig.
    The boat has got canting keel (70┬░overall) and 2 asymmetrical daggerboards.
    Thanks for your comments
    Stefano
     
  2. doesitfloat
    Joined: Feb 2005
    Posts: 19
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    Location: Michigan

    doesitfloat Junior Member

    To Chine or not to Chine

    I like the design looks fast. Here are a couple of coments I thought of.

    1. Chine
    What would happen if you put a hard chine in the aft end. Since this is a smaller version of the open 50 / 60 It would not help those big boats with a chine, But this is much smaller. It would flatten out the back giving more planning surface. Up wind it would be so far back on the waterline it shouldn't affect it much. This is coming from 49'er experience where digging the chine into the water helps at the start and in other low wind boat handeling manuevers.

    2. Swept foil
    Looks really cool but wouldn't it be easier to build and operate if it was strait. And able to change angle of attack. The ORMA 60's all have the articulating centerboard now, I race on a older Formula 60 we use a wood wegde to add 1/2 a degree to our centerboard and it makes a noticable differance.

    Nice boat though.
    Cheers
     
  3. nemo
    Joined: Apr 2002
    Posts: 132
    Likes: 3, Points: 0, Legacy Rep: 137
    Location: GENOA, ITALY

    nemo Naval Architect

    Never thought about that, sounds interesting..

    I put the swept foils for an interior arrangement problem: I prefer to have more free space afterwards the mast, but I still need lateral area after, so here comes the swept foil.
    Did you see the 2 foils on the bow? I put them to prevent nosediving, which is very common on this kind of boat. what do you think about that?
     
  4. DaveB
    Joined: Dec 2003
    Posts: 129
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    Location: Canada

    DaveB Senior Member

    Cp

    Is the Cp low or is it typical for these type of boats?

    I thought a good target was 0.55 +/- 0.05... smaller for light wind, bigger for heavy...

    Cheers,

    Dave
     
  5. nemo
    Joined: Apr 2002
    Posts: 132
    Likes: 3, Points: 0, Legacy Rep: 137
    Location: GENOA, ITALY

    nemo Naval Architect

    Yes sorry, some of the coefficients above were wrong!!
    So the real Cp is 0.545, while Cb is 0.350.
    The wetted surface also is wrong, because it was calculated with the keel. Without it, the wetted surface of the canoe body is 8.97 m^2
     

  6. nemo
    Joined: Apr 2002
    Posts: 132
    Likes: 3, Points: 0, Legacy Rep: 137
    Location: GENOA, ITALY

    nemo Naval Architect

    I developed my little design a bit more.. you can see it on
    www.delledesign.tk
    I added a couple of GZ curves.. do you think they could be comparable with other mini curves? I've never seen one..
     
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