Hull Offsets for SS United States

Discussion in 'Boat Design' started by johnhazel, Jul 9, 2014.

  1. johnhazel
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    johnhazel Senior Member

    Ah! I see what you mean now.

    The only choice I see is to increase the number of stations to 83, or 85. That way you can use the existing stations and only add the ones beyond the DWL. Leo's Program Flotilla can work with that file.
     
  2. Leo Lazauskas
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    Leo Lazauskas Senior Member

    Yes, it seems I was.
    At the scale of your 1st image on post #35 it looked like a slight jaggedness to
    me, but I now appreciate it is a very reasonable representation of the hull at
    the stern.
     
  3. Leo Lazauskas
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    Leo Lazauskas Senior Member

    My apologies for talking about jaggedness. It was the fault of old my eyes.
    Your work is terrific and not to blame.

    I understand what you are saying about having to use a different spacing if
    you want offsets at a different waterline.
    You can use any odd number of stations and waterlines up to any depth you
    like. Michlet and Flotilla can float the hull at any draft and they will take care
    of where the hull cuts the water. If the LWL falls between stations at the
    bow and the stern, the programs take that into account.

    If I use the hull as an example in the next versions of the programs I will
    certainly give credit to you and John Hazel in the manuals for your work.
     
  4. TANSL
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    TANSL Senior Member

    Okay Leo, let's be positive. What draft do you want to study and how many tranversales sections and water lines do you need?
    I´ll try to do my best.
    Cheers
     
  5. Leo Lazauskas
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    Leo Lazauskas Senior Member

    Very kind, TANSL.

    I would like lines up to a draft of 19.5m.
    81 transverse sections and 81 waterlines would be perfect for me.
     
  6. TANSL
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    TANSL Senior Member

    New data series, for D = 19250 mm.
    Any problems, do not hesitate to contact me
     

    Attached Files:

  7. Leo Lazauskas
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    Leo Lazauskas Senior Member

    Thank you, Ignacio.
    That gives me a good range of hull drafts to investigate the effect of weight
    on resistance and wave-making.
     
  8. johnhazel
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    johnhazel Senior Member

    So regarding an uappended hull calculation, Does it make sense to fill in the rudder cutout so that a clean skeg representing the rudder-skeg combination is produced?

    Beautiful work again TANSL. You mentioned a 3D model output. Is there a viewer you would recommend?
     
  9. TANSL
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    TANSL Senior Member

    Thanks John and Leo for your words.
    My software always works with AutoCAD so the solid 3D model is carried out in this program.There is a viewer for dwg files, which can be downloaded for free from the website of AutoCAD, to visualize dwg files, annotate comments, etc.. On the other hand, I can create a .igs file. This format can be imported into any CAD program you have at your disposal.
     
  10. johnhazel
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    johnhazel Senior Member

    IGS format please, Thanks.
     
  11. TANSL
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    TANSL Senior Member

    Solids "SS United States" 3D Model
     

    Attached Files:

  12. johnhazel
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    johnhazel Senior Member

    I have been looking at the bulb more closely this evening. It seems that in the reference diagram we are using that the bulb gets continuously wider moving from the bow. However in your PDF and table-of-offset there is a portion of the bulb that gets narrower (third fourth and fith stations from bow, the bulb is narrower than the second station). So I see why you are concerned with the area you indicated with the red oval.
     
  13. TANSL
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    TANSL Senior Member

    As I said in a previous post, a professional Loftman find errors in the fairing. Greatest I am even able to detect them. When I worked in shipyards, the person skilled in making a fairing took around a month to get the final shot.
    By the end we were looking for, it has not seemed necessary to reach more precision than we have. I could continue the smoothing case, if someone needs it, but that is a more important job.
    The model also has a major flaw: the feet of the frames are wrong because I have been unable to detect the width of the horizontal keel, which certainly exists, and how the curve of tangencies flat bottom.
    Not to mention the outputs of the axes of the helices (do not know the technical name in English). These appendices added frictional resistance, but I have not taken into account.
    We must also say that, starting from what we have, the corrections would be more in line with my special feeling, or my special clinical eye, tan supported by actual data of the fairing.
     
  14. NavalSArtichoke
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    NavalSArtichoke Senior Member

    I think here, 'helices' = propellers (helices = screws, literal translation from the French)

    The Big U did have some sizable shaft bossings, such that there were no exposed shaft struts, which would have added a significant amount of resistance to the bare hull. The shape of the bossings could be streamlined, where an exposed shaft could not.
     

  15. TANSL
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    TANSL Senior Member

    Yes, you are right, 'helices' (Spanish) = propellers.
    See post #15 to see the full stern of the ship.
     
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