1/4 scale model

Discussion in 'Sailboats' started by Howlandwoodworks, Jun 11, 2019.

  1. Howlandwoodworks
    Joined: Sep 2018
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    Location: Columbia MO

    Howlandwoodworks John Howland

    Hello,
    Here are a couple photos of my 1/4 scale model of a 16’ LWL & 27.5’ LOA, 2752, D/L 299.95, S/D 29.74, B/n 1.382,WS 122.95, 1300 lb. of leaded Full keeled, cine spoon transom, sloop rigged w/ warpable mast, or a small Lead Sled. Inspired by Herreshoff, Anker, and Cownishield . I am stand on the shoulders of giants. I made some Copenhagen Ship Curves a 1/3, 1/2, & full scale sets. All the curves on this boat are somewhere on one of them.
    My Construction Details Plans that are more inline with the 1800's methodology of construction, as my furniture has been. A third draft of Profile Drawings of Water Lines, Buttocks, and Diagonals sections are on my drafting table now. I have done a Saving to Investment Ratio on the cost of a 3D program, didn't pay off so I am using Excel. The 3D program would take the sport out of it for me anyway.
    Thanks to Eric Spomberg for his The Design Ratios 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) https://www.ericwsponberg.com/wp-content/uploads/the-design-ratios.pdf. His comment on the center of flotation and moving it forward as the boat heels over is one of the Herreshoff’s tricks has shed some light on the ever changing attributes of a sailboat for me.
    Will be add sails and lead to model this summer to see how it performs. If I can find a boat full of money somewhere I will start a full size boat. Building a model keeps me from losing my shirt but allows me to touch a dream. I am a custom design and build furniture company whom did his own designs for over 30 years and I detests fixing others mistakes.
    I have renovated some old fixer upper with papers already, here is one I kept. WISHING STAR https://www.woodenboat.com/register-wooden-boats/wishing-star-0
    If all else fails I will just go sailing. I guess that is the means to the ends anyway.
    John
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    Last edited: Jun 11, 2019
    The Q and Dolfiman like this.
  2. JamesG123
    Joined: Mar 2015
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    JamesG123 Senior Member

    Very nice!
     
  3. messabout
    Joined: Jan 2006
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    messabout Senior Member

    John, it is immediately apparent that you are a superb craftsman.

    The boat is a beauty. Now you can contemplate spending a bunch of money making it into an RC boat.
     
  4. JamesG123
    Joined: Mar 2015
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    JamesG123 Senior Member

    Its actually almost big enough to make one of those sailable scale models...
     
  5. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    The scaling of boats being a tricky matter, and probably especially sail boats, with regard to performance evaluation, is worth bearing in mind.
     
  6. Dolfiman
    Joined: Aug 2017
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    Location: NICE (France)

    Dolfiman Senior Member

    In France, there is an association of amateurs fan of such classic yacht and they did a revival of an old rule dated 1924, the "12 m2 du Havre", that corresponds to wooden keel boat of length ~ 7m, Lwl ~ 5m, beam ~ 1,6 to 1,7 m, weight 670 to 700 kg, of which lead ballast is 300 to 350 kg. Ideal for 2 people sailing , in my opinion the lowest scale which can still give the feeling and the elegance of a classic keel boat. Members of the association are amateur builders (but skilled !) able to do all the tasks, owners of historical boats, naval architects who proposed new plans in the spirit of Class ( a review of the old rule was established), new owners who build with the help of a professional shipbuilding, . ... You have a lot of info, photos, videos, boat plans (inc. mine , Dolfino, not built up to now), ...on this web site. That can be helpful for you to fix your new project, in case of you can contact them,
    Web site with the construction photos of the last one, Alcedo, plans by Bruno Jeanson, yard : Skol ar mor
    Construction de Alcedo chez Skol ar Mor http://12m2duhavre.free.fr/index.php?article67/construction-de-alcedo-chez-skol-ar-mor
     
  7. Howlandwoodworks
    Joined: Sep 2018
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    Location: Columbia MO

    Howlandwoodworks John Howland

    I have been working on some of the easy numbers in the hull design. Now I am looking up at the sails. I own a old 22" Star with a warpable mast, had a 18, Prindle Escape with full battened sail. I have never owned a gaff rigged boat, this daysailer over all shape originated from the days of gaff rigging 1800's. The hull shape below is a basic slow small lead sled.
    What type of sail configuration would be appropriate and any suggestions on information on sail design and there related/calculation unto the hull. I have calculated the center of effect of the hull in a upright position and am working on a heel over too 15%. It seemed a reasonable thing to do. Now the sails have many more options to them than the hull it seems to me. Some times when I think about all the relation between sail and hull it kind makes my head feel like it will explode and I am only working on a model. I can't change the viscosity of the water and air to match the models size. I don't know if that is a factor but it seems like it could be. ?? Then there is the emissivity of the surfaces of the material the boat is made out of it must have an effect. What I am trying to say is I have changed the boat size but the water and wind are the same. Is there enough difference in the elements as you scale down a boat size to make a difference? I realize that the atoms and molecules are all the same size but the amount are different.
    As a trailer sailor I have to set the mast each time I set out on the water. The wooden mast of the International Star is all I can do alone with the help of a shorter temporary mast. So one of my criteria for a sail is a mast that can be set by a young couple with some help from Archimedes, Suggestions please?
    I hope to put the model on the water under its own power to test how I have done on paper. Haven't figured out how to change the viscosity or the surfaces of the material yet. Hate to see it spin out of control or dive to Davy Jone's locker. So I keep reading, adding up numbers, and drawing.
    I look at sailboats hulls as fish and the sails as birds. Probably not the best starting point for designing a boat. The inspiration for the hull is a part of the Herreshoff legacy and a porpoise not a fish but has some of the same attributes. Seems to me most designer pre calculus days were coping what they saw in nature.
    I hope to incorporating the Humming bird some where into the design maybe in the shell blocks faces, or a relief carving in the bulkhead.
    Calculating a sail boats relation to wind and water is a complex thing, maybe 10 fold of what I though when I started.
    Well back to the drawing board. That is a photo of my spreadsheet in Excel. The Charts components in Excel has allowed me to see any measurement +-1/16 of an inch out of alinement in my Table of Offsets. Poor folks have poor ways.
    In the mean time I will keep searching the global brain, not the ischemia kind, but the world wide web kind.
    John
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    If you find any misspelling, bad grammar, inappropriate punctuations, or typo you may keep them.
     
    Last edited: Jun 13, 2019
  8. Howlandwoodworks
    Joined: Sep 2018
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    Location: Columbia MO

    Howlandwoodworks John Howland

    Hey JamesG123,
    Thanks, I was going to put one of my nephew kids in it. Got to teach them to sail, maybe swim first.
     
  9. Howlandwoodworks
    Joined: Sep 2018
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    Location: Columbia MO

    Howlandwoodworks John Howland

    Mr. Efficiency,
    Thank, tricky is a understatement, you were just being kind. I was a Energy Rater w/ RESNET certificate homes for the ENERGY STAR New Homes program, energy tax credits, and did Saving to Investment Ratios on home energy improvements like solar, wind, and geo thermal.
    A building attributes may change over the season but it doesn't move around from place to place. Then there is that model/scale thing that comes into play. I think maybe I should have my head examined.
     
  10. JamesG123
    Joined: Mar 2015
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    JamesG123 Senior Member

    Swimming lessons first would be the wisest choice.
     
  11. Howlandwoodworks
    Joined: Sep 2018
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    Location: Columbia MO

    Howlandwoodworks John Howland

    Dolfiman,
    Thanks for the information, I am concerned the whole thing has gotten out of hand.
    I saw your "Dolfino" she is de toute beauté. I believe she will take her passengers on wonderful adventure someday.
    On the 12m2 in Le Havre web site I saw many talent hands and minds there.
    I had a custom design and build furniture shop for 30 years, always had a apprentice around. I learned much from them.
    John
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  12. Howlandwoodworks
    Joined: Sep 2018
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    Location: Columbia MO

    Howlandwoodworks John Howland

    Well lets see, If I had three people say 512lb on board a full size boat, that would be 12.7 lb. for 1/4 scale model or three people of 4.2 lb. each. Well back to the drawing board.
     
    Last edited: Jun 14, 2019
  13. messabout
    Joined: Jan 2006
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    messabout Senior Member

    John, I believe that the 512 pounds at quarter scale results in 8 pounds. Use the cube of the scale to get a denominator. 4 cubed is 64 and 512/64 = 8

    If you intend to put a sail on it and put it in the water, you will need considerable ballast. More ballast than your narrow keel can accomodate. You would have to fatten the keel a bit so that there is space for a bunch of lead.

    Go to the American Model Yacht Association site and take a look at some of the different classes www.AMYA.org. There are all sorts of classes including some that are similar to your little beauty. Look at the EC12 class for example. That boat has a standard 17 pounds of lead in its belly.
     
  14. Howlandwoodworks
    Joined: Sep 2018
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    Location: Columbia MO

    Howlandwoodworks John Howland

    Maybe =sum12.7*12.7*12.7/4=512
    That is what I did at first too and came up with the 8 lb, but I think you have to divided the cube by 4 or 1/4.
    Well what do I know about it anyway. Just stared a couple month a go. I will look into it and hopefully learn something.
     
    Last edited: Jun 14, 2019

  15. Howlandwoodworks
    Joined: Sep 2018
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    Location: Columbia MO

    Howlandwoodworks John Howland

    messabout,
    I ran my calculations on the keels square footages and weights for the Deadwood and Lead for the full size boat and the 1/4 scale model.
    I am sticking with my originally calculations. of 1,301 lb.
    =SUM(17.33*17.33*17.33)/4=1,301.17
    That is 23 lb. of lead siting on top of existing cedar keel. It will be shaped and fitted into the dead wood.

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    Last edited: Jun 15, 2019
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