Value of trim

Discussion in 'Software' started by sujeethmonu, Aug 7, 2013.

  1. sujeethmonu
    Joined: Jan 2013
    Posts: 29
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    Location: india

    sujeethmonu Asst Professor(mech dept)

    In freeship, I tried to find the hydrostatics by entering the
    start draft=0m
    end draft=1.7m
    step draft=0.010m
    trim=0.377m (which is the default value when i opened "hydrostatics" under calculation tab)
    1) When i click on "hydrostatics", i get a window where the trim is default at 0.377m WHY?
    2) In "design hydrostatics" midship draft =0.377m. Is trim = midshift draft. I think Trim=draft forward-draft aft.
    I hope i'm not completely mistaken. Please help!

    i got hydrostatics till draft of 0.450
    evn if end draft is 1.7m. and the reason is leak point at/after 0.450m of draft
    but actually, trim is not equal to zero. because by running design hydrostatics (in "design hydrostatics.txt"), angle of trim=2.001dgr

    Part of the text file is as follows
    Parameters of ship sinkage:
    Difference of midship draft : 0.000 m
    Midship draft : 0.377 m
    Initial transverse metacentric height ho : 2.653 m
    Initial longitudinal metacentric height Ho : 21.125 m
    Angle of heel Psi : 0.000 degr
    Angle of trim : 2.001 degr
    HOW TO FIND VALUE OF TRIM IN METRES?
    OR AT WHICH POINT THE ANGLE OF TRIM IS MEASURED IN FREESHIP?
     
  2. Leo Lazauskas
    Joined: Jan 2002
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    "Assistant professsor" :p, please stop spamming us by putting the same post
    in different forums.
     
  3. sujeethmonu
    Joined: Jan 2013
    Posts: 29
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    Location: india

    sujeethmonu Asst Professor(mech dept)

    i m trying to get response. in desperation i m posting it in different forums. if you can help me out with this it would be good.
     
  4. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    sujeethmonu, If you knew what is the trim of a vessel, with hydrostatic data, you would have no problem in calculating the drafts at the forward and aft perpendiculars. So my advice is that before you go ahead, find out what is the trim.
     
  5. Olav
    Joined: Dec 2003
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    Location: Filia pulchra Lubecæ

    Olav naval architect

    Just made a quick and dirty sketch:

    [​IMG]

    Trim [m] = ΔT [m] = Ta [m] - Tf [m]

    Trim [m] = tan(Ψ) * Lpp [m]

    As you can see, it's just simple trigonometry...

    There is no point where the trim angle "is measured at" - it's just the angle between the (horizontal) baseline and the waterline.
     

    Attached Files:


  6. Leo Lazauskas
    Joined: Jan 2002
    Posts: 2,696
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    Location: Adelaide, South Australia

    Leo Lazauskas Senior Member

    It would help if you attached the file that is giving you trouble.
    If it is commercially sensitive, then attach one that exhibits the same problem.
     
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