sail boat design

Discussion in 'Sailboats' started by coastalrb, Dec 28, 2012.

  1. idkfa
    Joined: Sep 2005
    Posts: 329
    Likes: 6, Points: 18, Legacy Rep: 79
    Location: Windward islands, Caribbean

    idkfa Senior Member

    A 30fter is 8 times bigger than a 15fter! You can learn more from a dinghy than a keeled boat, cause a keeled boat forgives your trespasses if you get it less than perfect, also on a dinghy the forces are manageable. Imagine moving the mast forwards or back on 30fter to get the helm balance right?

    I built 3ft models, then small monos, cat and tri at 14ft before trying anything larger, all my own design, made many errors. Not too expensive and not too much time. And yes, read a few books too.

    If you've built smaller, then proceed with caution.

    When sort of performance are you looking for?
     
    Last edited: Jan 2, 2013
  2. coastalrb
    Joined: Dec 2012
    Posts: 9
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Clinton ct

    coastalrb Junior Member

    self taught

    Time is what i have. I am going to teach my self how to design a sailboat.
    I do not have the finanial ability to build but, this might become a model.
    The whole idea is to educate my self and know a lot about designing.
    I taught my self how to sail so i thougt with limited finances and a passion for boats i can change my career again and find something in the boat industry by leaning anything I can. So far so good.

    Thanks for all the thoughts
    Robert
     
  3. frank smith
    Joined: Oct 2009
    Posts: 980
    Likes: 14, Points: 28, Legacy Rep: 185
    Location: usa

    frank smith Senior Member

    Hi Coastalrb,
    Close to where you live there are many nice boats that can be gotten for a few thousand dollars , or maybe for free .
    But I understand the desire to design boats and other things. If that is on your mind, you will find a lot of help here. You will also find good critique.

    Have fun.

    F
     
  4. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    If you have a knack for engineering, higher math and convoluted complications that'll make you go prematurity bald, take up yacht design. Teaching your self to design a 15' daysailor that actually remains upright on launch day isn't terribly difficult, but a 30' yacht, well this is a whole different ball of wax.

    [​IMG]

    By this book; "Principles of Yacht Design", by Lars Larsson, Rolf E. Eliasson. Absorb it's contents and you'll have a good start on yacht design.
     
  5. coastalrb
    Joined: Dec 2012
    Posts: 9
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Clinton ct

    coastalrb Junior Member

    more

    Do boat designers have to register their designs and scantling numbest with a government agency or some kind of watch dog. Insurance companies need some kind of fact and figures to be sure.
    I am guessing this is a touchy subject.

    Robert
     
  6. rwatson
    Joined: Aug 2007
    Posts: 6,163
    Likes: 495, Points: 83, Legacy Rep: 1749
    Location: Tasmania,Australia

    rwatson Senior Member

    The closest thing to 'quality control' of designs is the concept of 'building to survey'.

    This mostly applies to commercial ships, and craft that are chartered, following several well known sets of classifications and design rules.

    have a look through the forum discussion on 'Class Societies'. This will give you a good insight into the problems associated with design.

    Insurance companies not only rely on the skills (and proven reputation) of NA's to design seaworthy craft, but in the case of smaller boats, the performance and reliability of various makes and designs over a number of years, provide them with enough confidence to provide cover.

    Its a bit of a mine field for insurance companies even with this system, particularly as the ongoing maintenance is as crucial to safety as the original design is.

    Happy researching.
     
  7. coastalrb
    Joined: Dec 2012
    Posts: 9
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Clinton ct

    coastalrb Junior Member

    I have principles of yacht design
    Robert
    Wow, an unregulated proffesion
    what does the coast guard have to say
    Robert
     
  8. rwatson
    Joined: Aug 2007
    Posts: 6,163
    Likes: 495, Points: 83, Legacy Rep: 1749
    Location: Tasmania,Australia

    rwatson Senior Member

    Its not that strange. Boat safety is 20% design, 30% individual trip preparation, 40% skipper experience and decisions, and 10% pure luck.

    Water is unpredictable, weather is too - the jobs that boats do range from carrying millions of tons of cargo to lone yachtsman on a tight budget, so its hard to have as tight a control on boat design as say autos and planes.

    There are lots of armchair designers who try to create the 'ultimate' boat - but the final result is a lot more than design. eg Titanic, Costa Concordia and dozens of smaller boats every year.
     
  9. coastalrb
    Joined: Dec 2012
    Posts: 9
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Clinton ct

    coastalrb Junior Member

    Don't foget MS Bounty
    Thanks for giving me something to measure against.
    Puting this Whole process in perspective
    I now know i have to get a planimeter to get numbers more quickly.
    Robert
     
  10. WhiteDwarf
    Joined: Jun 2011
    Posts: 131
    Likes: 5, Points: 18, Legacy Rep: 80
    Location: Sydney

    WhiteDwarf White Dwarf

    Half model?

    Robert,

    Have you considered making some half models. They would help you to refine your design with little cost. When you have one you think is promising, take the lines off it do the calcs and repeat the process.

    After that, build a scale model and sail it. Then contemplate a manageable build.

    The advice, start with something no more than 15 feet is spot on. Refining a dinghy or day boat is one thing, a 30 footer is eight times the volume and material, but with accommodation engine, wiring etc, it will be 20 times the work. It could well be both too big to fail and too big to succeed. A boat with no pedigree, has little resale value, unfortunately.

    Aircraft homebuilders say they get their permits to fly and their divorce papers in the same mail.

    Good luck and happy New Year.
     
  11. philSweet
    Joined: May 2008
    Posts: 2,682
    Likes: 451, Points: 83, Legacy Rep: 1082
    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    The best collection of comparative metrics for small craft that I have found is Chapter 9 of Ray Clark's Plyboats manual. Unfortunately, It doesn't seem to exist on the web. I have sent him an email requesting permission to post the chapter and it's graphs.

    One warning regarding comparative specs on sailboats though. Many boats in the 30' range were designed with some racing rule in mind. Designing to a rule means that a crappy boat is good if it rates even worse than it sails. So you need more than a modicum of background on the boats you chose to compare with. Don't mix boats that sail to different rules. Be mindful of rule changes and the years they went into effect. I see badly constructed sample sets used in some very ambitious documents. The problem is less acute in smaller boats that tend to compete one-design.

    Learing how to compare boats is an art in itself. See the thread here on Design Ratios.

    There is a concept in boat design called the design spiral; and the objective of a new designer should be to get once around the thing. I think Gerr's Boat Strength is a good reference for doing this.

    And for blue sky inspiration- 100 Boat Designs Reviewed
     
  12. coastalrb
    Joined: Dec 2012
    Posts: 9
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Clinton ct

    coastalrb Junior Member

    not able to build

    I do have a shop with a table saw and band saw and some old chisels. I have a piece of Angelique from the Amstad but Iam not sure.
    Is it all about shape and good fairing?
    That i can do.
    R
     
  13. coastalrb
    Joined: Dec 2012
    Posts: 9
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Clinton ct

    coastalrb Junior Member

    Gerr's boat

    thanks for the refference.
    I have just entered the spiral
    Hull and deck.
     

  14. idkfa
    Joined: Sep 2005
    Posts: 329
    Likes: 6, Points: 18, Legacy Rep: 79
    Location: Windward islands, Caribbean

    idkfa Senior Member

    For a performance boat, it is about stability and how much you can distort shape, and still call it "good shape" and conform to rating rule. To echo PhilSweet's warning.
     

    Attached Files:

Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.