scale model of prospective build

Discussion in 'Boat Design' started by spaceboy, Oct 27, 2013.

  1. michael pierzga
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    michael pierzga Senior Member

    Locally We have a hobby model building shop.

    They have a great selection of micro dimensional timber, hard and softwood, micro plywood, and micro tools like clamps, various glues , measuring tools , micro buckets of paint ....that model builders use.

    Do some googling to see if you have one of this shops nearby
     
  2. rwatson
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    rwatson Senior Member

    Have we have missed the real problem with Spaceboys model.

    What is the basis of the model ? Is it just some simple sketches, or a whole detailed analysis of a complete vessel ?

    For example - if he has trouble using a spreadsheet - has he calculated whether the boat will carry the required loads ,and will even float ?

    Then, have the scantlings ( material specifications ) been done ?

    If not, things like bulkheads, tanks, even the living quarters layouts will just be arbitrary bits of design.

    Also, if small models have little relevance to real life building, as the performance of the miniature hull material doesn't scale well. eg 15mm plywood in the full size, becomes just a bit more than a millimeter in smaller scales, hardly providing any real info on building techniques. With metal, its even more of a disparity.

    If this basic engineering work hasn't been done, there is nothing useful to be discovered in building a model.
     
  3. TANSL
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    TANSL Senior Member

    I quite agree with what you say, rwatson, you are mentioning some of the reasons why, for certain subjects, a physical model is not sufficient. But spaceboy already decided to make his 1/12 scale model. So let him do his model and check if, for what he needs, is sufficient or not.
     
  4. michael pierzga
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    michael pierzga Senior Member

    i assume that spaceboy has a design in hand and that he would like to do a trial run building a model to help him visualize the challenges of a full scale build. Not a bad way to go..scantlings and structural details arent so important.

    Its easy to state that torturing plywood or edge setting is troublesome....a model teaches you these lessons

    Recently on boatdesign net some asked if he could take 400 mm frame spaceing and substitute 600mm spacing.

    Perhaps..but when building a model he will learn that frame space is not only an engineering issue its a practical issue. You need the frame to develop a fair shape to bend the skin over...a model shows this
     
  5. rwatson
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    rwatson Senior Member

    Well, no its not the case.

    I tried to make that clear in my previous post.

    Scale materials have no relation to the real materials - therefore prove little.
     
    Last edited: Oct 29, 2013
  6. spaceboy
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    spaceboy Junior Member

    Thanks all for the advice and info. I can see that 3D software would be a very useful tool to have in the box. Tansl, thanks for the offer, something I will keep in mind.
    Sorry I didn't make it clear, I'm not designing a boat, I have a set of plans to build from.
    Michael has hit the nail on the head though, I want to build the model as I will build the boat, down to fabricating the frames from the loft floor, making as many parts of the model as will be needed on the boat. Modelling the interior, deck gear, spars and rigging.
    Yes I know it's a big boat, 57' LOD, approx' 30,000lbs of steel in it. I'm in the middle of estimating the steel cost at the moment. Not expecting it to be a small number.
    Space
     
  7. rwatson
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    rwatson Senior Member

    Now that that point is clear, there is an area that model can contribute to.

    I presume your plans are on 'paper', as offsets, hence your desire to loft them.

    It is an easy and fairly inexpensive process to transfer those offsets to 3d cad, and have them redrawn. A matter of a few hours by a CAD draftsman.

    From there, you can have the parts cut by CNC machine onto cheap sheet material ( plastic ? ) to any scale you want. 1:5 would not be unrealistic. This way you can actually check the parts accuracy, and fit them together, as well as the building sequence. I would be inclined to go as large as you can fit into your building space.

    The best part is that once those parts are 'proved' - you can get them upscaled to full size in a matter of minutes, and have them cut with plasma cutters for the real project.

    Trying to loft 1:12 scale components manually is not very productive, as the accuracy of the process would be hard to achieve. A manual cutting error of 2 mm ( the width of a jigsaw blade ) at 1:12 is a significant error at such a small size.
     
  8. El_Guero

    El_Guero Previous Member

    You are much more of a perfectionist than I am .... but sometimes doing it right is better than fixing it as you go.

    :)

    Wayne
     
  9. FMS
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    FMS Senior Member

    Both a computer model and a scale model are useful.

    When a builder isn't ready to start building for a year or more, doing a 3d model can provide a very precise understanding of how every element fits together. Individual elements can be turned visible or invisible to see what's behind. And it's possible to zoom in to see the exact clearance or shape at a specific point.

    Doing a 3D model also allows a builder of his own boat to make sure the design is exactly what he wants. For example, is the anchor locker space subtracted from the forward berth space something to question? Would an alternate dinette layout be possible? Are the windscreen frames exactly what he want's to see from the helm? These can be visualized with cardboard or wood too. The more complicated the constraining envelope, the more advantage the 3d model has over a cardboard model of the part and variation.

    (A NA selling plans may not want a builder to do this because of silly questions coming in or a builder deciding to make bad changes on his own because he can "draw". The builder spending real money has to know the limits of his ability. That's true regardless.)
     
  10. PAR
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    PAR Yacht Designer/Builder

    There's a huge difference between "doing a 3D model" and learning how to do a 3D model, when as the poster said, a spread sheet is more then they can handle currently. For this type of builder, there's no sense learning a new skill, for the one off return it might provide. Would there be advantages if he did learn, sure, but it's a steep learning curve for a spread sheet novice to get their head around and not necessary at all in the build, assuming good plans.
     
  11. TANSL
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    TANSL Senior Member

    No one is forcing anyone to acquire new skills. We are discussing the advantages of one type of model or another. As an advocate of virtual 3D model I can say that all the information that it's overwhelming a cardboard model also gets virtual model but in reverse is not true.
    It has been said that spaceboy would do well to learn how to make virtual models but has been encouraged to make the scale model he wants and find out to what extent is what he needs.
    It always makes sense to acquire a new skill. Sometimes the important thing is to park the skills that no longer serve much as formerly. Nobody has the right to discourage anyone to increase their knowledge. The more he knows, the less depend on people like us.
     
  12. El_Guero

    El_Guero Previous Member

    Hermano,

    No la intiendo esta <<As an advocate of virtual 3D model I can say that all the information that it's overwhelming a cardboard model also gets virtual model but in reverse is not true.>>

    And please forgive me for my bad Spanish, my learning Russian gets in the way.

    Wayne
     
  13. PAR
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    PAR Yacht Designer/Builder

    Your logic isn't sound. I have a toothache, so should I study dentistry? I want to build a vacation home, so maybe I should take up architecture?
     
  14. TANSL
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    TANSL Senior Member

    El_Gero, what I mean is that, in my opinion, with a computer model you can extract more information than from another made ​​of cardboard. Your Spanish is enough, thanks.
    PAR, you can learn what you want, each administers its shortcomings as he wants. Spaceboy apparently wants to make a model of his boat and does not seem unreasonable to say that, if he wants, could learn how to do it with a computer. If, in addition, he wants to learn dentist with you, good luck to both. Do not have serious arguments to counter mine?
     

  15. rwatson
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    rwatson Senior Member

    Anyone planning to build a 60ft steel boat who thinks they can get a handle on its build process with an 18" cardboard model, is a real optimist.

    If they didnt want to learn 3d CAD, then a relatively small cost to get a 3d image and cutting files made up is a really viable option.

    Not getting 3d design done on a project of this size is like digging your shed foundations with a mattock instead of a backhoe.

    As Tansl has so wisely said before, to be able to rotate, reveal, analyse the components of the build on a computer monitor is a huge benefit for the builder.
     
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