newtimer with some questions about design/construction

Discussion in 'Sailboats' started by opteek, Nov 15, 2005.

  1. opteek
    Joined: Nov 2005
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    opteek New Member

    Hey guys, new member here with a couple of questions. I want to eventually design and construct a large catamarn for ocean-cruising in luxurxy. I have no experience whatsoever with boat design or construction, just some sailing, not much at that. I'm a 20 year old college student studying computer science. I have full access to a machine shop and am a quick study.

    I was wondering how feasible is it for me to educate myself to the point of designing a practical blueprint of such a catamaran, perhaps so that I may take it to a professional designer for review for a moderate fee or somesuch.

    I imagine the construction itself is a bit easier than designing the boat? Around how much would it cost to build a 12m fiberglass catamarn, ballpark price.

    And finally, I would very much appreciate any book reccomendations on the theory of sailboat design and construction. I have a strong background in calculus and calculus based physics, if that helps.
  2. Inquisitor
    Joined: Nov 2005
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    Inquisitor BIG ENGINES: Silos today... Barn Door tomorrow!

    I don’t have the benefit of your youth, but our eventual goals are very similar. This forum will be your best resource! In general, most everyone will offer constructive advice and criticism based on years of experience and are willing to share that wealth with you. My background is more engineering based; however, I am not a boat architect and being land-locked all my life, my sailing experience is non-existent. I would first suggest you read as many architects sites as possible and find an architect that shares your philosophies. Here are a few I found.

    Select your architect. No matter how knowledgeable, educated, gifted or lucky your are, you will miss some very important aspects. Starting with someone’s plans will assure you get at least most of it right. The more you diverge from the plans (at your own risk) the more risk you take on.

    Start out with something small and try your theories on that. This has several benefits. It lets you see how thorough your chosen architect’s plan are. It lets you get your hands sticky and your failed tweaks won’t cost you as much.

    Price… since there are so many levels of fitting, a stripped one might set you back $70K once loaded up it might go $700K.

    Books - Although its for mono-hull design, I would recommend highly “Principles of Yacht Design” by Larsson and Eliasson. Catamaran design should be similar for pitching, but roll design characteristics will be totally different. However most everything else will be pertinent. At the very least it will allow you to talk the common language to architects here on this forum and in person.

    Hopefully someone else can offer books of a similar analytical detail that are more specific to catamarans. I’ll be tracking this thread for it!

    Good luck with your quest!
  3. opteek
    Joined: Nov 2005
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    opteek New Member

    Thanks for your detailed post. I have read about the fboats before and have heard very good things about the detail of the plans that they offer. I like their designs as well. I'm seriously contemplating buying the plans for one of their boats as my first project.
  4. Skippy
    Joined: Nov 2004
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    Skippy Senior Member

    opteek: I want to eventually design and construct a large catamarn for ocean-cruising in luxurxy. I have no experience whatsoever with boat design or construction, just some sailing, not much at that.

    In all the reading I've done on boatbuilding, including both books and project websites, there is one universal rule that almost every author has insisted on:

    *** START SMALL ***

    With a big project, it's very easy to find you've bitten off more than you can chew, abandon the project, and have nothing to show for your effort. With a smaller, simpler boat, you'll probably be able to complete construction of your own hand-built boat and be able to sail it around the local water any time you want. I would build a small one-man boat first, then some kind of daysailer, then consider more extensive projects.

    Here are some helpful links:
    The Rules
    Ted Brewer's boat design primer
    A high school with a boatbuilding class
    Lots of free small-boat plans

    These are some books I've found interesting, informative, and enjoyable to read:

    Ted Brewer, Understanding Boat Design (beginner)
    John Teale, How to Design a Boat (intermediate)
    Larsson & Eliason Principles of Yacht Design (advanced; I haven't read, but people swear by it)

    Robert M. Steward, Boatbuilding Manual

    David Gerr, The Nature of Boats: Insights and Esoterica
    Philip C. Bolger, Boats With and Open Mind
    Bernard Smith, The 40-Knot Sailboat (exotic: hydrofoils, flying proa)

    Smith's book got me excited about sailboat design. It's more about setting speed records than general all-purpose sailing, and some of his ideas haven't worked out. But it's still fun. :)
  5. prp25brad
    Joined: Mar 2005
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    prp25brad Junior Member

    I have a very similar background as poster stated above. I too would like to build a large cat sometime in the near future. I have taken hard learned lessons from other aspects of my life and have already decided that I should design a smaller boat first. But that leads to the main question I have, what size to start with? Does it do much good to design a 15' cat or would it be better to start in the 25' to 30' range? The 25' to 30' range would be my preference, but is that getting too far?

    Then then next question is what to use to design. I use AutoCad all day long so 2D model is a snap. I can do 3d modeling in AutoCad but that is very cumbersome. So where to start? I see tons of programs being discussed but not sure what to start with. Usually one would start from the bottom up so I guess I need a hull program to start or just a simiple 3d modeling program to get a design down and have it critiqued on this forum.

    Well hope I gave enough questions to answer :D
  6. fhrussell
    Joined: Dec 2004
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    fhrussell Boatbuilder

    Just a few other resources:

    The Gougeon Brothers On Boat Construction (a must)
    The Cruising Multihull by Chris White
    Fiberglass Boatbuilding for Amateurs by Ken Hankinson
    Lofting by Alla H. Vaitses

    Definitely, start small. If this is a first time build, make it simple too. Build any kind of boat, like a pram or dinghy, just to get used to using the tools and epoxies and so forth. It's all fairly easy, but best to make any mistakes on that dinghy first. In the meantime, read up on catamaran design and figure out what your operational envelope will be. Often people will get themselves into a boat that is ready to world cruise and then never go out except on 5 -10 knot wind days and sunny skies. A simple daysailor would have been fine. And I'd bet that's 95% of most boaters!
    But if world cruising is your thing, you'll be very busy reading anything you can get your hands on about offshore cruising and offshore boat design.
    Don't get me wrong, any good boat is designed well to withstand harsh conditions, but some are designed to stay in protected waters, too.
    There are few greater feelings of pride and acheivement than building and sailing your own design... even better when it handles well and, of course, is beautiful.
  7. nero
    Joined: Aug 2003
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    nero Senior Member

    the number of small

    Small is relative. The way I saw it, is the smallest boat to meet your needs (not wants). From surfing the net and comparing layout plans, visiting other cats, I settled on 14 meters. It is my first boat project. Only design something if you can not find a plan that you like.

    Perhaps it is your first boat, but not your first building or design project. Experiance from other projects can translate directly to what you will be doing in the building process.

    The hardest part to figure out is how to structuraly connect the two hulls. I have found no books on this. The bridge deck structure has very few examples posted on the web. Overly simplistic view, I thought FEA software could magically show me where my 3d cad model was structuraly sound. (maybe it can, still pursuing this) There are no scantlings for catamaran cross structures!?

    Timewise, what ever you build, it will take 2 to 3 times your estimate to complete. Cost of materials can be $30,000 for hulls and structures. (I seem to be coming in at this cost) Probably another $30,000 for the rest (guess) There are many techniques and materials to build a boat with. Catamarans can not use every technique.

    I bought TouchCAD for the 3D modeling. Have used VectorWorks/MiniCAD for years. Use it to label and present my building plans with. TouchCAD is extremely easy to produce smooth, fair hulls. I will attest that it is highly accurate. My bulkheads were within 1 mm when setting them into the hull. My forms were dead on too. All this from x,y coordinates plotted by hand.

    If you want to build something quickly, do not use strip planking. If you want something round, then it is very strong and resists abuse.

    Do not play soccer at age 40. Rupturing an achiles tendon and the 4 months it takes to recover does not advance a DIY boat project.

    Keep at it.
  8. trimarandan
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    trimarandan Junior Member

    although i havent built a boat yet i did buy an old 38' Cross Trimaran and through the process of fixing it up i've tought myself countless valuable info on boat building. in my opinion, if you didnt want to start small, buy and old boat similiar to the one you want to build and learn from it and get accustomed to sailing it so you know what you want when you do build one. by owning one similiar you can actually see diferent aspects of what it takes to build a boat and why its done that way as you restore it, which i find to be way more helpfull than reading it someware or just blindly taking someones word for it. as far as this process being expensive, it varies, with enough searching you will defenatly find a very reasonable price for the right boat, for examlpe i found mine for 17k and with the work i put into it as of now i'de say its worth about 30. (i may make money off this one) the most important thing to remember is to take your time and not rush into things.
  9. SAQuestor
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    SAQuestor Senior Member

    Why Design?

    When I bought my first computer I thought I wanted to learn to program. It didn't take me too long to decide that I didn't really care about programming.

    What I did decide is that I wanted to generally know how a program worked and then I concentrated on the hardware aspects of computers. Eventually I built my own computers and futzed with the various pieces of hardware until commercial computers got "good-e-nuff" for me to just buy a box and forget about all the bits and pieces.

    Approaching boat design is (in my mind) the same sort of dilemma. Do you really want to know all the ins and outs of boat design (programming) or do you just want to use the results?

    I've no real interest in the minutia of ratios and all the etcetera that goes into a competently designed hull. I just want to know that the designer understood all of those numbers and got them correct for what the boat is supposed to be optimized for.

    So - several things that I've learned over the past 5 years of researching boat designs.

    All boats are a compromise.
    Change one parameter and it affects at least one other parameter - and often several others.

    Probably most important - closely define what you intend to use the boat for. Coastal cruising? Ocean crossing? Tied to a dock in a marina? Primarily deep water or lots of shoal? Go fast or not? Spartan or luxury accommodations?

    The questions - and resulting answers - are myriad. Each choice dictates other choices by either expanding the options or limiting the options available.

    Read all the books that others in this thread recommended - each book read will lead to other areas to educate yourself in, which in turn..., etc. etc.

    My best advice? When you feel comfortable that you know the characteristics of the various hull forms, sail rigs, engines, electrical and gear choices and their strengths and weaknesses, then you can choose a designer that has similar designs and hire them to design a boat to your specifications - and if you still want to build it yourself, they'll design it with that option in mind.

    All of this "knowledge acquisition" is so that you'll be able to carry on an intelligent conversation with the NA/designer of your choice.

    And so you will not have the wool pulled over your eyes by some fly-by-night individual that you meet in the bar over by that marina on Saturday afternoon after you've looked at 4 different boats and talked to 3 different brokers who tried to tell you that that particular boat was "perfect" for your intended use.

    But unless your career goal is as a naval architect, leave the minutia to the professionals and just give yourself a good general boat education. Then go out and earn the money (in a profession that you enjoy) it will take to make your dream a reality.


  10. gonzo
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    gonzo Senior Member

    The design and construction both have degrees of difficulty. It takes about 15 to 20 trades to build a boat. The skill to do so require several years to learn. In the ballpark, to build a boat of that size to "cruise in luxury" would be U$200 to 300 K. This is not including labor.
  11. D'ARTOIS
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    D'ARTOIS Senior Member

    On the financial side, Gonzo is quite correct in his statement/guestimate; but and that is the big but, if you can indeed pick up things quickly, it will take you at least 5 years to know what you are saying - not what you are doing, add for that another 5 years.
    Visit as many boatshows as you can, pester as many shipyards as you can, read as many books as you can, sail as much as you can, repair boats as many as you can, help other people repairing their boat as much as you can, maybe wisdom will come.......
  12. gonzo
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    gonzo Senior Member

    Sailing a lot, repairing your own and other's boats can let you gain skills prettty fast. It is, in some ways, better than working at a commercial yard where they have to make a profit on your labor. They can't afford to let you take time to learn and experiment.

  13. cyclops
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    cyclops Senior Member

    I was born to be in water. My mother said of me." He will come home in the middle of the desert with mud on his shoes. "----------------------- As a result I progressed quickly from models of 8', fully Radio controlled to woodies. I burned a lot of firewood over the years. Buut, I am more than qualified for the next one. I think I could do it with out plans. There is definately a hump. Once you cross it, you will know it. It feels ALMOST as good as sex. Except it is not as tiring. :)
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