result in hydrostatic report

DELFTship forum Hydrostatics and stability result in hydrostatic report

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    • #34473
      Thomas Vochezer
      Participant

      Hi,

      I have a problem with the hydrostatic report. Although I filled out the density and thickness for each layer in the layer properties menu, I don’t get the resulting weight of the layers in the hydrosatic report. The weight of the layer is only shown in the properties menu. What is my mistake?

    • #34475
      Marven
      Keymaster

      Can you add the report as attachment?

    • #34477
      Thomas Vochezer
      Participant

      Hi Marven,

      thanks for your mail. Please see attached the PDF of the hydrostatic report and the PDF of the related layer properties. As you can see, the weight is calculated in the property sheet.

      [file]
      [file] [file name=Layer_properties_Daysailer.pdf size=281617]http://www.delftship.net/delftship/media/kunena/attachments/legacy/files/Layer_properties_Daysailer.pdf[/file]

    • #34479
      Thomas Vochezer
      Participant

      Hi again,

      I didn’t catch how to attach two files. So now the second PDF [file name=Hydro_Daysailer.pdf size=76029]http://www.delftship.net/delftship/media/kunena/attachments/legacy/files/Hydro_Daysailer.pdf[/file]

      Attachments:
    • #34480
      Haider
      Participant

      Hi vochezer

      I can see something not right in your thicknesses. In the hydrostatics report, you can see in the main characteristics, the Mean Sheel Thickness: it is 0.01 meters. This is almost 10 mm for a boat of 5 meters long……your layer thickneses are way to thick….

    • #34481
      Marven
      Keymaster

      Not if your building in wood……

      Anyway, it seems you’re correct. I’ll dive into this next monday and see if I can figure out what’s wrong.

    • #34482
      MICHAEL KERR
      Participant

      Hi,
      if your hull thickness is 10mm try enter it as
      10.00 not as 0.01 it works for me.

      The below is from a post I did a couple of days ago.

      Hi Baran,
      for example, mild steel weights 7850 kg/m3 so it would be entered in the Density column as 7.850 , (lets say plywood weights 368 kg/m3 so it would be 0.368) , if your steel thickness is 10mm that would be entered in the Thickness column as 10.00 after you enter your density and thickness press Enter so its locked in, then go to Design Hydrostatics, you will see a list of all your Layers, they will include Layer Name, Area, Thickness, Weight and the 3 COGs, this will be automatically transfered to Load Cases under Lightship. Let me know how you go ?

    • #34483
      otaku
      Participant

      Hahaha… a little humor here: I was thinking “armored, 5-m boat”, before thinking about wood.

      Cheers!

    • #34484
      Thomas Vochezer
      Participant

      Hi Mike,

      thanks for your tip. You are right, when I input the thickness dimension in millimeters I’m getting the right result and it is displayed in the hydrostatic report.

      By the way the hull is out of wood. I’m actually finishing this boat and want to compare the reality with the output programm data.

      Thanks although to all other to help solute my problem.

      Thomas Vochezer

    • #34488
      MICHAEL KERR
      Participant

      Tom,
      I’m always right, in the end ! :S

    • #34545
      Paul Badcock
      Participant

      Hello All, Have a question….. Mike you might be able to help me, Am I right in thinking the Loadcase part of the program could be described as a Graphical spreadsheet. So.. I design my yacht with hull,deck ,keel,cockpit cabin and some blk hds then get the weight and centre of gravity of all this and do I have to manually input this in the Lightship line in the loadcase window? Cheers

    • #34546
      Papp Miklos
      Participant

      Sorry!

      Please, delete the letter.

    • #34547
      Papp Miklos
      Participant

      Yes! The thickness must be in 10 mm and not 0.01m, the result is tonnes!

    • #34548
      MICHAEL KERR
      Participant

      Hi Jet28

      (Loadcase part of the program could be described as a Graphical spreadsheet.)
      Yep that sounds about right, or a graphical set of scales. Once you give your layers weight and thickness, its my understanding that this is auto transfered over to Loadcases and its incorporated in the Lightship weight, but there is also more weight in there besides whats in layer properties.

      Marven could you give us a short explanation as to what else is included in the Lightship weight, just for clarity sake? (pretty please)

      Mike

    • #34551
      Marven
      Keymaster

      Mike wrote:

      Marven could you give us a short explanation as to what else is included in the Lightship weight, just for clarity sake?
      Mike

      The weight from the layer settings is not automatically included in the lightship weight. You will have to enter this manually in the list. The weight of the shell usually is only a fraction of the total light ship weight, so in most cases you will have to enter many more weights, such as stiffeners, welding tolerances (or glue or screws in the case of wood), foundations, windows etc.to calculate the final weight.

      The program then combines all these weights into the final lightship weight and center of gravity which are used in the load cases.

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