Sailboat Design Project

Discussion in 'Sailboats' started by Thorpydo, Sep 11, 2007.

  1. Thorpydo
    Joined: Sep 2007
    Posts: 11
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    Location: San Diego

    Thorpydo Junior Member

    My first post on the forums... Sounds like a great community!

    My name is Adam. I'm a fourth year mechanical engineering student.

    I like sailing and I want a sailboat. I am crossed between a) buying a boat. b) building a boat from existing plans. c) designing and then building that boat.

    I would like to do c), design and build the boat most, as that would be most rewarding to me. I am willing to put in the time, effort, and learn the "learn how" of boat design. My only reluctance is making a boat that barely sails.

    The goal of my boat would be something that I could take up and down the coast here in San Diego and possibly something that I could sleep in and go on a several day trip with. I would bring a bag lunch :). I have sailed holder 14's before and imagine that a boat of ~20' would be suitable. It needs to fit in my garage for the build and needs to be trailerable.

    I have quite a bit of experience with the CAD program solidworks and wouldn't have a problem finding things like the center of gravity or the buoyant force. I have taken a fluids class but the closest we come to boat design is the "self righting" principle of boats. I see there are programs like "Michlet" that will allow me to optimize the hull shape. Other than that, I would be researching and asking here.

    My first thinking is to build a boat using the "stitch and glue method". It sounds like a fairly straightforward, quick and dirty approach that gives good results. I have used wood and fiberglass before and don't think I would have too much trouble with the construction.

    I don't have very much knowledge of other types of constructions. I got some books from the library but they are from the 40's and 50's so I imagine much has changed.

    What do you guys think?
  2. tspeer
    Joined: Feb 2002
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    Location: Port Gamble, Washington, USA

    tspeer Senior Member

    If cost is the major driver, you can't build a boat for less than you can buy a used boat with similar capabilities. Think of all the hardware and sails that come with it. So if you want to sail, that's the way I'd go.

    If you are more interested in building than sailing, then by all means go with c).

    I would buy a used boat and build a dinghy for it. That gets you on the water the fastest and the cheapest, while still scratching the itch to design and build something.

    Even if you are building a cruiser, you can build a dinghy and then build the cruiser faster than you can build the cruiser by itself. That's because you learn so much building the dinghy that the time spent is more than made up by increased efficiency building the cruiser.
  3. Guest625101138

    Guest625101138 Previous Member

    My advice is virtually identical to Tom's.

    The cost equation - The hull is about 1/3 the overall cost of a boat. Rigging and sails another third. The rest is taken up in providing accommodation and getting it to the water. Most boat owners do not bother to keep tally of all the little odds and ends added to the boat over time so secondhand boats tend to be undervalued. The negatives become exaggerated and the positives get glossed over when the time comes to move upmarket or move on. Here is one recent example of a good buy.'s boat
    In the end a boat is worth what someone is prepared to pay for it. Pleasure boats are purchased for pleasure and many buyers lose their interest as the gloss fades and the repairs mount. Some trailer boats are simply expensive garden gnomes that are hard to mow around.

    Experience - Sailing experience will help tremendously when you start a design. Your education combined with experience should be a good base for understanding loads and material stresses.

    Skills - Building skills and knowledge also come with experience. It is best to use the skills you have developed and progress from that base.

    Typically wooden boats take more care with storage and/or have higher maintenance costs than a composite or aluminium boat.

    You can get great satisfaction from designing and building a boat so if that is your main purpose then you can pick up a lot of insight by asking targetted questions here. Building models of various scales can help you along the learning curve and provide a bit of fun along the way.

    Rick W.
  4. bistros

    bistros Previous Member

    Advice from someone who's doing what you are thinking about

    My opinions reflect the same theme as others. Do not discount the time and money it takes to get things done and right.

    I intended to take the same path and design a hull, but quickly learned the learning curve is too steep to get a boat on the water in less than two to three years, given the time it takes to learn the tools, learn the craft and most importantly decide what you want to accomplish. I proceeded to work with an accomplished naval architect to handle design, while I concentrated on building, rigging and testing the design. There are lots of design decisions that need to be made before setting offsets and drawing a hull.

    I'm an engineer by trade, but naval architecture is a field with enough details and subtleties to demand years of study to become functional.

    You would be far better off to follow the above advice and spend time on the water in a used hull - to teach you what you do and don't like about an existing design - which provides the best foundation for beginning a design process of your own. Over 20 years of practical engineering I've learned that it is a far easier process to learn what's wrong about an existing design than it is to predict and document what a new design should be. Call it ready, fire, aim development - this is how the real world works instead of the ready, aim, fire method they try to teach us in school. The problem with school is that they never tell you clients have no substantive idea what they truly want and need, although clients can tell you what they don't like in exhaustive detail.
  5. Phil Stevo
    Joined: Feb 2004
    Posts: 33
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    Location: Sydney

    Phil Stevo Junior Member

    Good advice here.
    Start with something small and work up. You get better as you go.
    I am about to start boat number 25 and consider I am still learning.
    (even after 38 years of Engineering and 43 years of amateur boatbuilding)
  6. Thorpydo
    Joined: Sep 2007
    Posts: 11
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    Location: San Diego

    Thorpydo Junior Member

    Hey guys,

    After reading the advice here, my plan was to buy a ~22" boat and build a small one man boat.. I really liked that idea, best of both worlds. Unfortunately I didn't consider my car and pulling a boat. I have a 95' mazda 626; average 4 door car. I'm convinced that pulling a 22' boat in a car like that is not safe for me, the car, or the boat. Buying a pickup truck is an expensive route, initial cost and the gas milage.

    I've since decided that it would be a better idea to build a small one man, possibly two laser type boat. I still want to get a bigger boat, but will wait until I'm out of school and have more money to buy a truck and boat.

    I want to build it vs buying it because I am excited about the build. I am still unsure if I will design it myself.

    Do you guys think it would be feasible to tow a small laser type boat from my car?

  7. bistros

    bistros Previous Member

    I've built a 14' high performance composite construction singlehanded skiff this year. The completed, glassed, epoxied and faired hull weighed 74 pounds before paint and rigging, and the complete finished boat with all rigging weighs 125 pounds.

    To answer your question, yes, you can tow or rooftop a homebuilt boat.

    You would have to build out of ferro-cement to make a two man dinghy tough to tow.
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