Problem with Tables of Offsets

Discussion in 'Boat Design' started by Proflooney, Dec 26, 2016.

  1. TANSL
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    TANSL Senior Member

    I think you're doing well. It's totally normal, if the hull is not smoothed, you should see lumps like the one you have on the left-hand frame.
     
  2. Proflooney
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    Proflooney Junior Member

    Ok I got the station curves all in they are pretty screwed up so gonna take a while to get them figured out
     

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  3. Heimfried
    Joined: Apr 2015
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    Heimfried Senior Member

    The lines you show in #15 don't look like lines of a boat hull at all. And the indicated axes of coordinates (y,z) are not used in the common way.

    May be you should take a bit more time to compare the drawings of the boat and the offset table to understand the relation better.

    Edit: I didn't see TANSL's post #16. He is much more experienced than I am.
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    Houston, we have a problem.
     
  5. TANSL
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    TANSL Senior Member

    The pictures in post # 17 may well be the cross sections of a ship, although there are many shortcomings and probably not well located in space. But I think the OP is laying the correct groundwork to start a "fairing" job, which will certainly not be easy.
    Mr Efficiency, no need to call Houston, a simple loftman will be a much better help.
     
  6. Heimfried
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    Heimfried Senior Member

    The y,z coordinates of station 7 fed in a web tool to create cubic splines are showing a fair curve, not a curled one.
     

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  7. JosephT
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    JosephT Senior Member

    Yes those lines look a bit lumpy. I would be inclined to take any sketches/photographs of the hull and loft it from scratch. From there you can optimize the curves, run your stability & resistance checks on it, etc. until you achieve the performance you like.
     
  8. Proflooney
    Joined: Nov 2016
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    Proflooney Junior Member

    yes I was just entering the curve tables from the offsets and those are the lines. I havent had time to check all the lines and the views above were taken in perspective some curves are fine while others very lumpy. plus I dont like the way they sit I want to do up the hull but since im so new at boats I wanted to try with the offsets table first

    Now here was my Fletcher Hull using the Offsets I also did the SS United States with offsets. so normally I been doing good learning how to use them but this little boat seems FUBAR. I even tried delftship but that prog doesnt like me at all rofl. I figured this would be easy to do and I could make a boat out of it by spring to take grandkids radio control boating but right now doesnt look like it.
     

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  9. Proflooney
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    Proflooney Junior Member

    Here is what I did last night before generating the curve txt files.

    I too the data from the original and reorganized the table to be more like I am used to seeing.

    Now Solidworks needs the coordinates set up the Following way to generate the curves Properly:

    Station Waterline Offset

    I just need to put a space between each and stack them for each station and each station needs to be a separate txt file. to the right of the table I have them set up as individual stations and I just copy and paste the data into notepad.

    I am just thinking the offset table data is way out of whack and when they laid down the hull and fixed any errors it didnt get adjusted in the offset table
     

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  10. JosephT
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    JosephT Senior Member

    It's easy to get lost in offset tables with a lot of entries. If only certain stations are affected I would isolate those and double-check the numbers for them. If they match the person defining the table probably made a mistake. You'll need to adjust the best you can.

    I prefer to loft the lines in DelftShip or another good lofting tool, refine the splines (remove kinks & wrinkles), run all my calculations (hydrostatics, resistance) then export only the basic splines required to define your surface in SolidWorks (e.g. top profile, side profile, stations at 12" intervals). The exported splines will likely need to be scaled as well to match the units in SolidWorks (e.g. meters to mm).

    Cheers,

    Joseph
     
  11. Proflooney
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    Proflooney Junior Member

    that would make life easier joseph however when I try to do anything in delftship my hull looks like a crumpled wad of paper. I will have to see if I can figure out how to get the offsets into the program and see if I can fudge in there. I am not holding my breath but like said I am still learning and for me its more for virtual modelling and radio control.

    my radio control boats only round 6 ft long so any flaws really stand out
     
  12. Proflooney
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    Proflooney Junior Member

    Ok I just finished tracing all the lines from the lines drawing sheet and saved them to DXF format after enlarging them to full scale. Now I will try to pull them into Delftship and see if I can figure out how to adjust everything to match without getting some crumpled paper again
     
  13. JosephT
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    JosephT Senior Member

    Looking at your old table it will require conversion to the DelftShip format, which is basically listing your stations along X, and filling in points for Y & Z. Below is a sample input file. This example is for a simple canoe with a closed bow & stern (note 2nd column is at 0 (zero) to close them up.

    If you can get your points into this format you're all set.

    1

    0 0 0
    0 0 .17
    0 0 .33
    0 0 .5
    0 0 .67
    0 0 1.5

    1 0 0
    1 .0625 .17
    1 .1146 .33
    1 .1667 .5
    1 .2188 .67
    1 .3229 1.3021

    2 0 0
    2 .1563 .17
    2 .2708 .33
    2 .3646 .5
    2 .4479 .67
    2 .6563 1.1979

    3 0 0
    3 .2708 .17
    3 .4479 .33
    3 .5833 .5
    3 .6875 .67
    3 .8229 1.073

    4 0 0
    4 .4271 .17
    4 .6458 .33
    4 .7813 .5
    4 .8854 .67
    4 .9896 .9791

    5 0 0
    5 .6042 .17
    5 .8229 .33
    5 .9688 .5
    5 1.0521 .67
    5 1.125 .9063

    6 0 0
    6 .7708 .17
    6 .9792 .33
    6 1.0938 .5
    6 1.15625 .67
    6 1.1979 .8646

    7 0 0
    7 .90625 .17
    7 1.0938 .33
    7 1.1875 .5
    7 1.2188 .67
    7 1.2292 .8333

    8 0 0
    8 1 .17
    8 1.1563 .33
    8 1.2292 .5
    8 1.2396 .67
    8 1.2396 .8333

    9 0 0
    9 1.0313 .17
    9 1.1771 .33
    9 1.2396 .5
    9 1.25 .67
    9 1.25 .8333

    10 0 0
    10 1.0104 .17
    10 1.1563 .33
    10 1.2292 .5
    10 1.2396 .67
    10 1.2396 .8438

    11 0 0
    11 .9375 .17
    11 1.0938 .33
    11 1.1771 .5
    11 1.1979 .67
    11 1.2083 .8542

    12 0 0
    12 .7912 .17
    12 .9688 .33
    12 1.0625 .5
    12 1.1042 .67
    12 1.125 .8958

    13 0 0
    13 .5833 .17
    13 .7813 .33
    13 .875 .5
    13 .9271 .67
    13 .9583 .9583

    14 0 0
    14 .3542 .17
    14 .5208 .33
    14 .6146 .5
    14 .6563 .67
    14 .6979 1.0521

    15 0 0
    15 .1354 .17
    15 .2292 .33
    15 .3021 .5
    15 .3334 .67
    15 .3646 1.1875

    16 0 0
    16 0 .17
    16 0 .33
    16 0 .5
    16 0 .67
    16 0 1.3334

    EOF
     

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  14. Proflooney
    Joined: Nov 2016
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    Proflooney Junior Member

    I will try as I tried to pull the drawings in at full scale as png files and the program is giving me errors.

    will see what I can come up with. what format does delftship use as for locations like i said solidworks uses stations, then waterlines, then offset data
     

  15. Proflooney
    Joined: Nov 2016
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    Proflooney Junior Member

    here is what my txt file looks like with everything brought into it.

    station 0 in the drawings is the transom and station 10 is in the bow

    Station 0
    792.00 135.500 62.000
    792.00 120.000 64.000
    792.00 108.000 65.000
    792.00 96.000 65.000
    792.00 84.000 59.000
    792.00 72.000 41.000
    792.00 60.000 63.000

    Station 1/2
    753.000 131.250 70.000
    753.000 120.000 71.000
    753.000 108.000 72.000
    753.000 96.000 72.000
    753.000 84.000 69.000
    753.000 72.000 58.000
    753.000 60.000 17.000

    Station 1
    714.000 129.750 77.000
    714.000 120.000 78.000
    714.000 108.000 79.000
    714.000 96.000 77.000
    714.000 84.000 76.000
    714.000 72.000 69.000
    714.000 60.000 47.000

    Station 2
    636.00 127.750 87.000
    636.00 120.000 87.000
    636.00 108.000 87.000
    636.00 96.000 87.000
    636.00 84.000 86.000
    636.00 72.000 82.000
    636.00 60.000 72.000
    636.00 48.000 44.000
    636.00 36.000 16.000

    Station 3
    558.00 127.000 93.000
    558.00 120.000 93.000
    558.00 108.000 93.000
    558.00 96.000 93.000
    558.00 84.000 92.000
    558.00 72.000 89.000
    558.00 60.000 82.000
    558.00 48.000 61.000
    558.00 36.000 34.000

    Station 4
    480.00 127.375 95.000
    480.00 108.000 96.000
    480.00 96.000 95.000
    480.00 84.000 95.000
    480.00 72.000 93.000
    480.00 60.000 86.000
    480.00 48.000 72.000
    480.00 36.000 43.000

    Station 5
    402.00 128.750 96.000
    402.00 96.000 96.000
    402.00 84.000 95.000
    402.00 72.000 93.000
    402.00 60.000 87.000
    402.00 48.000 73.000
    402.00 36.000 44.000

    Station 6
    324.00 131.500 96.000
    324.00 120.000 95.000
    324.00 108.000 95.000
    324.00 96.000 94.000
    324.00 84.000 93.000
    324.00 72.000 89.000
    324.00 60.000 82.000
    324.00 48.000 67.000
    324.00 36.000 41.000

    Station 7
    246.00 135.500 94.000
    246.00 132.000 93.000
    246.00 120.000 91.000
    246.00 108.000 89.000
    246.00 96.000 86.000
    246.00 84.000 82.000
    246.00 72.000 77.000
    246.00 60.000 63.000
    246.00 48.000 55.000
    246.00 36.000 33.000

    Station 8
    168.00 141.600 86.000
    168.00 132.000 82.000
    168.00 120.000 77.000
    168.00 108.000 72.000
    168.00 96.000 67.000
    168.00 84.000 61.000
    168.00 72.000 55.000
    168.00 60.000 47.000
    168.00 48.000 37.000
    168.00 36.000 22.000

    Station 9
    90.000 149.900 64.000
    90.000 132.000 52.000
    90.000 120.000 46.000
    90.000 108.000 41.000
    90.000 96.000 37.000
    90.000 84.000 32.000
    90.000 72.000 28.000
    90.000 60.000 23.000
    90.000 48.000 17.000
    90.000 36.000 9.000

    Station 9 1/2
    51.000 154.750 42.000
    51.000 132.000 30.000
    51.000 120.000 26.000
    51.000 108.000 23.000
    51.000 96.000 20.000
    51.000 84.000 17.000
    51.000 72.000 15.000
    51.000 60.000 11.000
    51.000 48.000 8.000

    Station 10
    12.000 159.750 9.000
    12.000 132.000 5.000
     

    Attached Files:

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