exporting in Michlet

  • gianlisi

    gianlisi - 2006-03-02

    Dear Marven,
    I noticed that while exporting the hull in michlet, the LOA is used.
    Thus (I think), a wrong B is obtained in Michlet (I don't know how it calculates that).
    That does not happen if, instead of the LOA, the LWL il used. In this case, the right BWL is calculated by Michlet.

    I'm using Michlet for a very low LWL/BWL hull (that is  4,14), but so far it seems to fit quite well with the Delft Series, (DSHYS93, DSYHS98 and DSYHS99). More data may be available soon (but I've got no experimental data about it).

    Secondly, in the "calculations" -> "hydrostatics" menu, the trim is intended to be expressed in [m].
    How can I do that? I often found it measured in [°]... am I wrong?



    • Marven

      Marven - 2006-03-02

      I'll dive into that and check things. I'm very interested in the coparison of the Delft series and results from Michlet. I also think Leo Lazauskas (author of Michlet) would be interested.

      Trim in degrees is arctan(trim/lwl). I'll see if I can include a switch in FREEship to choose between trim in meters or trim in degrees.

      • gianlisi

        gianlisi - 2006-03-02

        Ok! I'll let you have my comparisons as soon as they are ready.

        Have you got some experimental data to check out too? would be interesting to me for a validation of the code (for low LWL/BWL, of course). I think it is not include in the validation excel sheet.

        About the trim... where is it then measured? is it then the difference from the displacemente along the FPP and the displacement along the APP? sonuds good...



    • gianlisi

      gianlisi - 2006-03-03

      An Excel sheet with a comparison among the three DELFT series and michlet for a bare hull is ready... seems to fit really well.

      where can I email it to you and to Mr. Lazauskas?

      I've got some problems with keel... seems to be loaded in Michlet wrongly. The BWL turns out wrong even if the LWL is used and, in the waterline plot, the keel seems to be plotted forward the waterline.
      I imported the keel as a part in the Free!ship file, maybe can cause problems. so they are two separate surfaces.
      Have you already had to deal with that? Otherwise I'll try to connect the two bodies, to check out what happens.



      • Marven

        Marven - 2006-03-03

        Hi Gianluca,

        Please e-mail the Excel sheet to info@freeship.org.
        I'll forward it to Leo for you.

        If you can also send me the file causing your problems with Michlet, I'll have a look at it. I'm not sure but if I recall correctly the export to Michlet expects 1 surface (keel and hull joined). Anyway, I'll have a look and update the program if needed/possible.

    • gianlisi

      gianlisi - 2006-03-04

      Hi Marven!
      The export in michlet now seems to work good, even if they are two surfaces. I maybe made a mistake while positioning the keel, so a very strange surface appeared in the file (I left the root and the tip five meters behind the rest of the keel!).

      Secondly, I do thin the LWL is required as an input in Michlet. if you check out the out.mlt file, the L is reported next to LPP label.

      I mail the excel sheet to you!

      thanks for the wonderful program (wich is rescuing my thesis!)


    • Nobody/Anonymous

      Hello all,

      I see ths thread is old but here goes anyway:

      I have also noticed this LOA/LWL anomaly when exporting to Michlet. My workaround is to manualy edit the .mlt file.
      I am comparing families of slender hulls and using the wrong LWL means the skin friction to wave drag ration gets skewed.




Log in to post a comment.

Get latest updates about Open Source Projects, Conferences and News.

Sign up for the SourceForge newsletter:

JavaScript is required for this form.

No, thanks