To design a sailing dinghy

Discussion in 'Education' started by jalmberg, Aug 13, 2016.

  1. jalmberg
    Joined: Oct 2009
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    jalmberg Junior Member

    Hi hope this isn't too naive a question, but nothing ventured...

    A little background: I live in Huntington, NY where William Atkin had his first boat shop, and belong to the yacht club he helped found (he was the head of the race committee), and I've built John Atkin's "Cabin Boy" flat-bottom skiff. I also own a Tom Gilmer "Blue Moon" yawl. So a bit of experience with building and caring for wooden boats.

    The other day, I found a drawing of a sailing dingy from 1895 that really captured my imagination, and after mulling it over for a while, I decided I should try to design and reproduce it.

    I've been looking for a book to get me started, but most seem oriented towards yachts and ships. Worse, I doubt the person who designed the boat I'm interested in was a trained designer. It was probably a design that a boatbuilder evolved over many years to fit a specific local environment.

    So my question is a bit different from the other "can you recommend a book..." questions. My question is: how did olde-time boat builders design small craft, without formal education? And could I reproduce that process today?

    Food for thought: as far as I know, William Atkin was self-taught.

    Any ideas?

    TIA: John
     
  2. JSL
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    JSL Senior Member

    Boats were built long before they were designed. If your design evolved from a proven boat (ie: and 'as built' drawing) it will probably be okay.
    There are many good books ...Skene's Elements of Yacht design is one. Dave Gerr's books are good too. Also Ed Monk, William Garden, etc
     
  3. jalmberg
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    jalmberg Junior Member

    I have a bunch of books on the way through inter-library loan, but I'm thinking (perhaps wrongly) that they are going to be focused on yacht design, not so much on dinghy design.

    That's why I'm wondering if there is a more straightforward approach, like finding a number of boats that are similar to what I'm looking for, using them as a starting point, analyzing them to see why they work and don't work, and then working from there.

    I'm guessing that is closer to what was done before naval architecture was formalized into a science.
     
  4. PAR
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    PAR Yacht Designer/Builder

    No, only until relatively recently have yachts (and their little sisters) been engineered. Don't kid yourself, the non-engineering types that did design boats, had such a keen feel for the shapes involved and the scantlings generally employed, they were nearly engineered anyway. A person that performed this would have had a few decades in a shop, under apprenticeship or the tutelage of a master, eventually becoming brave enough to carve up a model or apply pen to paper. Many small craft were done this way and the successful ones (many more not successful ones) were from those that had considerable practical understanding.

    The general rule for your first boat design is, don't venture too far out on the limb. By this I mean you model the boat after something known to do well, for your goals. As you learn what works (and painfully, what doesn't), you refine subtle things, seeing what it does, eventually honing down your skills, so you can muster up grander plans and venture farther out on the design limb. Simply put, you crawl, stagger, walk (with lots of falling) and sooner or later you'll be able to run.

    If you have lines for this boat, it should be a simple matter of drawing up something quite close, but this isn't the real question you should ask yourself. Ask yourself if this design is well suited for your needs. Aesthetics can easily be applied to about any hull, making a Cal 20, look like a mini friendship sloop above the LWL, just with a canoe body hull and modern appendages below, for example.

    I did a reproduction of an antique design about 18 months ago. The client was in love with the look and insisted I use Chapelle's lines, offsets and appendages. He wanted a gentleman's day boat for his retirement years, after decades of sailing performance dinghies, he just wanted a nice relaxing, simple little boat. I tried to explain this was an antique and nothing like what he was use to and probably way too twitchy for his liking, but again, he insisted. The boat was built as desired and he put it up for sail after a few months of ownership, complaining it was way too tender and "spirited" as he put it.

    My point is, be careful what you wish for, as these antique designs don't sail anything like what you might expect and even worse, may be a lousy design to begin with. You see, the guys that sailed these puppies in the golden age of sail were a whole lot better than use. Even an average sailor, could beat the crap out of the best modern Olympic gold medalist in one of these boats. They grew up knowing nothing else, often went to work or actually worked on a sailboat. They didn't have motors to bail them out when they no brained themselves into a situation, so they were much more in tune with the wind, weather, rig, even the sound of the boat underway. I've sailed many antiques over the years and it always surprises me, how much the old timers would tolerate. We're pretty spoiled, but they didn't have a choice, so they made the best out of a witch and still managed to come home alive. The message here is, it's difficult to tell what the boat is like, without a good bit of experence evaluating lines.

    Post some lines or whatever images you might have. Odds are one of us knows something of the boat, maybe where to find more information. Don't hold your breath on plans, but maybe a construction drawing or an idea of scantlings would be nice.
     
  5. jalmberg
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    jalmberg Junior Member

    Gosh, I'm quite reluctant to post this image, because I can practically guess the reaction from a bunch of hard-nosed engineer type (I'm an engineer myself, but also a writer).

    So, this is a painting by the French artist Émile Friant. It dates from around 1895. Émile was a realist painter who -- it is said -- often worked from photographs to get the details just right. I mention this to fend off comments like "it's only a painting". The more you look at this painting, the more details you find that ring true, so I believe it is a good representation of a particular type of French boat. I'm digging into the historical details elsewhere, hoping to discover where the actual boat was located, and perhaps who the couple in the picture were.

    I guess the artist took a few liberties... putting the lazy lout of a boyfriend on the leeward side, for example. Seems quite an unlikely place to be with the sails so full, but from a composition viewpoint, he look better where he is.

    The hull looks fairly straight forward, but the rig is amazing to me. I'm guessing this boat evolved in an area plagued by light winds... much like my own Huntington Harbor in July and August. I'm guessing there were also a few bridges in the area, since the mast is fitted with a tabernacle. The tiller is short, but I wonder if that isn't another reflection of the light-wind environment, or just a concession to decorum... makes it easier for the lady to shift from one side to the other without looking too unlady like!

    This is just a taste of the many details in this painting that I find fascinating. Call me crazy, but I would love to sail this boat, in France, on the same river. It seems like a fairly small and simple hull (though quite wide) so hope it is within my rudimentary building abilities.

    Anyway, here it is.

    [​IMG]
     
  6. gonzo
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    gonzo Senior Member

    He took more than a few artistic liberties. A boat of that size and shape, with two adults by the stern would be having the bow pointing up to the sky.
     
  7. PAR
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    PAR Yacht Designer/Builder

    Agreed, that isn't an image, so much as an artistic fantasy of a little dinghy, with way too much sail area, way too short a tiller, etc., etc., etc.

    If you want something like this, there are lots of choices (small lapstrake dinghies) to choose from. Most will not have nearly as complex a rig as shown, but if you insist a lug sloop can be arranged, if a bit impractical on a boat of this length (8'?). I can only imagine the Chinese fire drill necessary to tack that puppy, but a pretty picture it does make. I wonder if the skipper has to move the mainsail tack around to the other rail on each tack.

    [​IMG]

    A lug (cat, not a sloop) Gartside of similar proportions.
     

  8. jalmberg
    Joined: Oct 2009
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    jalmberg Junior Member

    That design might be a good place to start... I'll give Paul a call and see what he thinks.

    Thanks.
     
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