Where to start when designing my first small sailboat?

Discussion in 'Boat Design' started by trackie2, Apr 1, 2021.

  1. trackie2
    Joined: Mar 2021
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    Location: Victoria BC Canada

    trackie2 Junior Member

    I would like to preface this post by saying I have absolutely zero knowledge or experience with designing boats. Where should I go to learn more about how to design small monohull sailboats? Do any of you have suggestions on books or websites I should look at? I have a basic idea in terms of shape and size in my head but I don't know how to verify it would work or design it in CAD.

    Thanks :)
  2. mc_rash
    Joined: Aug 2020
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    Location: Netherlands

    mc_rash Senior Member

    This forum is a good start :p

    First you should make a state of requirements where you make clear what kind of sailboat you want to design (for racing/cruising? daysailor or do you want to stay a long time on it? length, passengers,...)
    Then you should search for boats that would fit with your design in dimensions, intention of the boat etc. and draw up a al information you can get from these boats for example in a tabel (displacement, length overall, waterline length, breadth, draught (with and without keel), sailarea, engine(-power), ballastweight,.. in other words everything you can find.
    For every boat you can define some coefficients blockcoefficient, L/B, L/T, Displ./ballast, Displ./L, Sailarea/Displ., and more.
    With you comparison-boats and the coefficients you can get a first idea of what are good values for your own design.
  3. sharpii2
    Joined: May 2004
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    Location: Michigan, USA

    sharpii2 Senior Member

    Welcome to the forum, trackie2.

    There are two ways to go about this:
    1.) the imitate while making small changes. You see a boat that is close to what you want, you copy it as much as you can, while changing it ever so slightly to meet your specific needs. You alter the hull shape not at all.
    2.) learn as much as you can about boat design theory by buying books about it and by taking courses on it.

    The bigger the 'small boat', the more theory you are going to have to learn. You are also going to have to learn at least a little about structural engineering. And learning that, outside of a degree program, will prove somewhat difficult.

    You might have a natural ability in this field, a kind of intuitive understanding. But, by hanging out at the waterfront, and learning as much as you can about boats similar to what you have in mind, can go a long way.

    If your ideas are very unconventional, this strategy will not work. Then you will have to learn the facts of boat design, including and especially stability. Mean old Mr. Math has scuttled a lot of my seemingly brilliant ideas. Many of yours may suffer the same fate. It's far better to find this out on paper, before sinking a lot of time and money building something that will not work.

    You will probably start with a preliminary design, which can be drawn with nothing but a pencil, a piece of paper, a ruler, and a calculater. Oops, I forgot to include the most the most important tool: an eraser.

    If you know what ortho-projection is, you are at least prepared to start. If you don't, take a drafting course.

    I don't mean to lord over you that this is a task for only trained professionals, but there is a mountain of knowledge that needs to be learned before you can even start.

    My first book was SKENE'S ELEMENTS OF YACHT DESIGN. It is far from complete, but it does cover a considerable amount of the structural engineering (almost exclusively in wood), and some other design topics.

    Another book I have is THE PRELIMINARY DESIGN OF BOATS AND SHIPS by Cyrus Hamlin. THE BOAT DATA BOOK is another good one to help you make a lot of calculations.

    None of these are complete, but they somewhat compliment one another. But there's a lot of imformation they leave out.

    They are at least a good start.
    Last edited: Apr 1, 2021
  4. Will Gilmore
    Joined: Aug 2017
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    Will Gilmore Senior Member

    Hello trackie2, welcome and as mc_rash says, this is a good place to start.
    Tell us a little more about your design career plans. Are you looking at becoming a professional designer or do you just have a design in your head that you want to learn how to render into a home build, or is it somewhere in between with a few ideas and an interest in learning about a serious hobbie?

    The depth and effort you choose to put into boat design can go anywhere from learning how to draw up a buildable sailing dinghy in your garage to the exacting mathematical calculations of balancing foil lift versus heeling force that would make a rocket scientist sweat.
  5. clmanges
    Joined: Jul 2008
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    clmanges Senior Member

    Ask yourself why you want to learn such a new and very specialized thing as boat design (specifically, small sailboats). Have you ridden in one and caught the bug? Just seen one (in real life or otherwise) and had it take your breath away?

    You may find out that what you really want is just to have a boat of your own. Designing even very small sailboats can quickly become an enormously complex task, as you may have already gathered from the above responses. Lifetime professionals still crank out bad mistakes.

    Experience aboard real boats is essential, IMO. If you haven't yet, try to hitch a short ride on someone else's small sailboat. Talk to as many owners as you can find, and ask them about the best and worst things about boating in general, and their boat specifically. This will teach you things you can never learn from a computer (and I think it's good to learn pencil-and-paper calculations first).
  6. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    It is good, very good, to have that experience, but it is not essential, IMO. Does a NASA scientist need to be an astronaut? Does an aircraft designer need aircraft experience, other than as a passenger? Can't a person with a severe motor disability design boats?
    Can a sailor, with 4 sails around the world, design boats? Not necessarily, surely he can't.
    Can someone without physical experience aboard a ship design ships? Of course he can, IMO.
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  7. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell . . . _ _ _ . . . _ _ _


    Welcome to the Forum.

    The first place to start is answering the question:
    "Why do you want to design your first, small sailboat?"
    Is it just an exercise, or for a friend perhaps, or
    do you intend to build the design you create?
    Why, basically is the first question to answer.
    Also, what is the "small sailboat" for?
    Where, here?
    Lots more questions but that should get us started.

    Victoria BC Canada
  8. Ike
    Joined: Apr 2006
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    Ike Senior Member

    Trackie, you live in an area that probably has more sailboats per capita than many other places. I suggest you visit some of the marinas and sailing clubs and take a good look at the boats. Talk to people about their boats. It's too bad you can't cross the border now, but maybe by September, because right across the water from you is Port Townsend, Washington one of the centers of boatbuilding in the US. In September they have the Woodenboat Festival. Hopefully this year it will be in person. Plus that, the Woodenboat Foundation there (they put on the show) has a terrific library chocka block full of books on boat design. As was suggested read up. Lots of good books on the subject. Or you can start by looking on the web, just google "Small sailboat plans". They will give you plenty of ideas.
  9. rangebowdrie
    Joined: Nov 2009
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    rangebowdrie Senior Member

    "It's so very easy to draw/design something that's so very hard to build"
    Good boats pretty much follow the "KISS" principle, and are easy on the eyes.
    Although I would never call myself a "designer" per se, getting a "feel" for certain elements is a good start.
    Several decades ago I started out by devouring every design he did,, and one could easily do worse.
    Atkin & Co. - Boat Plans (atkinboatplans.com)
    Last edited: Apr 2, 2021
    Will Gilmore likes this.
  10. Howlandwoodworks
    Joined: Sep 2018
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    Location: USA MO

    Howlandwoodworks Member

    I am just starting myself, a couple years in now and it seems like I know less than when I started. I guess that's just part of the learning process.
    Here are just a couple of the references that I have used besides the great help here on BoatDesign.net.
    Using the search in the upper right hand of this screen for previous posts about your questions is something I could/should have done more often. Well, hindsight is 20/20.
    Mr. Sponberg Design Ratios are a great place to start. As for CAD program am not using one. )junk in gunk out(. That is not to say it wouldn't work for you.

    A Naval Architect’s Dozen (or thereabouts)
    A primer on some basic principles of naval architecture for small craft. As first published on BoatDesign.net, January – March, 2010.
    By Eric W. Sponberg Naval Architect BSE, PE (CT) CEng (UK)
    Articles https://www.ericwsponberg.com/articles/
    You can get your feet wet here.

    Principles of Yacht Design
    - By "Larsson, Eliasson"
    A great one, I liked Fig 1.1 The design spiral, it show 11 different segments of a boat design, but the spiral seems to go on into infinite for me.

    My intentions here are not to implicate anyone in my mathical reckless behavior.
  11. DCockey
    Joined: Oct 2009
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    Location: Midcoast Maine

    DCockey Senior Member

    trackie2, What size "small monohull sailboats" are you interested in designing and what would the boats be used for? Under 20 foot in length open boats for recreational sailing? 35 foot boats for racing?
    bajansailor likes this.
  12. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell . . . _ _ _ . . . _ _ _

    It seems Trackie's got cold feet.
    Just respond briefly to each post, in order, Trackie.

  13. Kayakmarathon
    Joined: Sep 2014
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    Kayakmarathon Senior Member

    Learn by building 1.0 - 1.5 meter ( 40 - 60 inches) models out of balsa wood strips or panels. This will give you tangible feedback a 3D computer model can't. You will also gain a sense of designing for manufacturing (DFM).
    Will Gilmore likes this.
  14. trackie2
    Joined: Mar 2021
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    Location: Victoria BC Canada

    trackie2 Junior Member

    Sorry, I realize I should've included this in my initial post. I want to build a sailboat for the micro transat challenge The Microtransat Challenge http://microtransat.org/. The boats attempt to cross the Atlantic and are autonomous. They must be under 2.4 meters long but apart from that there aren't any real constraints in terms of building. I need my boat to be stable (needs to stay upright and be able to self right), durable I want to have the only moving part be the rudder like the Sailbouy from Offshore Sensing Offshore Sensing - Sailbuoy - Home http://www.sailbuoy.no/. One day I'd like to build smaller scale models to test my electronics, programming, and design. However, right now I just want to learn the very basics of designing a hull, and after that learning what shapes and sizes the sail and keel should be.

  15. trackie2
    Joined: Mar 2021
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    Location: Victoria BC Canada

    trackie2 Junior Member

    I replied below with some information I really should have put in my post about the kind of boat I'd like to build one day. Luckily the MicroTransat Website (The Microtransat Challenge https://www.microtransat.org/tracking/index.php) has a list of boats that have made attempts so suppose those would make good options for comparison? Thank you for your reply I really appreciate it:)
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