Delftship table of offsets format and measurements

Discussion in 'Software' started by Davesea, Dec 7, 2012.

  1. Davesea
    Joined: Nov 2006
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    Davesea Junior Member

    I am new to Delftship and I plan to be taking off lines from my 23' skiff and want to make all the correct measurements for a txt file that I can import as a table of offsets.

    I need some clarification on how to measure the following from Page 19 of the manual.

    1)read deckline-Illustraion 1.7. "deckline height and beam measured on each station"

    2)read contour- Illustration 1.8 : "height of contourline on each station"

    3)read aft contour- illustration 1.3 "distance of aft contour line to origin on each water line"

    4) read forward contour- illustration 1.5 it describes it as "distance of forward contour line to origin on each waterline.

    Would someone clarify how to measure these when taking off lines?

    regarding #1 does deckline refer to sheerline?
    for 2-3, not sure what "contourline" refers to so I need clarification on this.

    Also what is "read flat of bottom" and where do you enter it into the text file?

    Thanks,
    Dave
    Seattle
     
  2. Davesea
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    Davesea Junior Member

    Importing Chines worked

    Here is the line plans of my boat that I measured. I used the chine import to import the waterlines.

    Any comments?
    The line drawing is attached.
    Dave
     

    Attached Files:

  3. DCockey
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    DCockey Senior Member

    Does the physical boat have the lumps and bumps?
     
  4. Davesea
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    Davesea Junior Member

    David,
    Yes, for a couple reasons. 1. It is a Lapstrake fiberglass hull. So depending on where the points are measured, it can look bumpy in the measurements. The other reason is is at the stern the transom was widened from the original mold and it is not the smoothest transition. So it bulges in and then out at the transom.

    Dave
     
  5. DCockey
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    DCockey Senior Member

    Lapstrake results in waterlines with steps, not the lumps you show. It can considerably complicate modeling the hull surface and then getting a "good" set of lines starting from measurements.

    What do you intend to use the Delftship model and/or lines for?
     
  6. Davesea
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    Davesea Junior Member

    No specific plans for the model. Just trying to document my one (maybe more) off hull.
     
  7. DCockey
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    DCockey Senior Member

    My preferred method for lapstrake hulls is to measure along the laps at the inside corner or outside corner. Then create curves along the laps and fair those curves. Depending on the shape of the hull and what the lines/model will be used for I may create a smooth model based on the lap curves. I have also created a model individual planks surfaces. I use Rhino so don't know how to do it Delftship or even if it is possible.
     
  8. Davesea
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    Davesea Junior Member

    There are only three strakes, so my next model will use the lapstrake lines as you suggested.
     

    Attached Files:

  9. Davesea
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    Davesea Junior Member

    Another iteration using the lapstrakes as chines

    Still need to clean this up. But shows a much different picture....

    Updated the line drawing with some clean up. Looking better.....
     

    Attached Files:

  10. DCockey
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    DCockey Senior Member

    A major improvement.
     
  11. Davesea
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    Davesea Junior Member

    Water line and displacement are way too high. Not sure how to control that?
     
  12. lewisboats
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    lewisboats Obsessed Member

    You have to to into properties and change the waterline to what you want. It isn't automatic.
     
  13. Davesea
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    Davesea Junior Member

    Got it thanks Steve. Changing the draft brought the displacement in line.
     
  14. rwatson
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    rwatson Senior Member

    Did you find the answer to your original questions ?

    It would be good to post them here for other users.
     

  15. Davesea
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    Davesea Junior Member

    Yes I did answer my own questions.
    1) Deck line is sheer line
    2) Contour line is the keel line height(z) at x=0 and y=0.
    3) never determined what "read flat of bottom" was

    I was not able to import the table of offsets into Delftship, but I was successful at importing chines which are XYZ along a longitudinal (lengthwise) line. In my case it was easy to follow the lapstrakes as the chines and then using the keel or countour line and the deck line. Easy file to import as X, Y, Z and then this same file can be imported as Markers to show your original data.

    I will eventually do a youtube tutorial of how I took off the lines. The laser cross line level made the process less painful and more accurate. Using the cross line level laser was a suggestion of Tad Roberts.
    Dave
     
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