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  • #85320
    Billy Oram

    Hello all. I was reading the numbers to a Formosa 51 on Sailboat Data and saw that the Bal/Disp figure is 21.43. I was surprised to see it that low. What does this figure translate to? What I gather is that it is vulnerable to wind but what does that mean as the other numbers say that it is a slow, heavy and safe blue water boat? Thanks

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  • #85324

    Hi Billy, We took another look at the Formosa 51. We tweaked it a bit but our record now matches a Formosa Boat Building Co brochure. The ballast weight they list seems low but it’s what they report.

    Billy Oram

    Bruce, thank you for the reply.

    Lynn H. Ogden

    You wrote in part:
    ” What does this figure translate to?”
    See the below link for useful sailboat ratio information and calculations.

    [Sailboat Guide — Discover your dream boat] (https://sailboat.guide/calculations)


    **”Sailing isn’t a sport, **
    **Sailing is a way to get somewhere. **
    **Riding a Bus isn’t a sport, **
    Why the fuck is sailing a sport?”
    George Carlin; 1984


    Just FYI… everything you see on sailboat.guide, from sailboat specs to information on designers and builders to associations, everything, was taken without permission from us.


    I know this is old but I’ll take a stab at it.
    What does it translate to…I thought about that and it’s a great question. The ratio itself is simple, it’s the weight of the ballast relative to the weight of the whole boat.
    Your question, posed another way, I think is, what would be different between two similar boats with very different b/d ratios?
    The only thing I can think of is if you have a boat with a smaller radio, or, less difference between the weight of the ballast versus total weight, then you might have less stability, a lower comfort ratio, and worse capsize recovery ability. I’m guessing, just to start a conversation which might draw out the guy who knows!
    I’m curious about the purpose of “double enders” or “canoe” stern boats?
    Thank you:)


    The definition is difficult to understand.
    Stiffer, doesn’t seem like a ratio of weights can determine stiffness of a boat, but I’m not sure.
    More powerful: seems like power comes from the sails, not the relationship between weight of the keel and weight of the boat, but I’m not sure.
    Better able to stand up to the wind: same answer.
    Any hull designers out there? Help?
    A Ballast/Displacement ratio of 40 or more translates into a stiffer, more powerful boat that will be better able to stand up to the wind.
    Bal./Disp = ballast (lbs)/ displacement (lbs)*100


    Stiffness refers to a boat’s ability to resist healing. The opposite would be tenderness. The more ballast, as a precent of the displacement, the better the boat stands up to the wind. Keep in mind, the location of the ballast can also have an impact on stiffness.

    Hope this helps.

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