Sharat Jami

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  • in reply to: Stability question for autocad and delftship users #38980
    Sharat Jami
    Participant

    Hello ICare,

    Your Idea is nice where TCB becomes LCB & Vice versa, it will work,

    DS is analysing only Longitudinal Stability in free version so you change Transverse stability to Longitudinal,…..also make sure you give frame of reference at amidships for a clearer understanding.

    in reply to: P factor Calculation for Passenger Ships #38979
    Sharat Jami
    Participant

    Ok Found it….The Algorithm is in MSC 216 82

    in reply to: Stability Book – Hull form #38603
    Sharat Jami
    Participant

    Hey Brian,

    I can share some booklets which i did, but if you need exactly for the specs mentioned above then a new one is to be prepared, I doubt nobody will do it for free…

    in reply to: Heeled Waterlines and Calculating Righting Moment #38527
    Sharat Jami
    Participant

    Dear Jayoh,

    It is possible to export DS to freeship by exporting as parts,

    Or else you can purchase inclined hydrostatics extensions from DS, if you want to avoid hassles between two softwares.

    in reply to: Heeled Waterlines and Calculating Righting Moment #38524
    Sharat Jami
    Participant

    Dear Sir,

    I understood your discussion, the procedure elaborated by you is perfect, but the results you asking cannot be found on free version of Delftship, it can be found in much primitive version called Freeship (Absolutely free to use GPL)….

    TCB can be seen in design hydrostatics…..

    But VCG is not a hydrostatic property it depends on weight, you have to tediously compute each and every detail of material you are using…

    I hope i have resolved….

    Capture.png

    Capture-1.png

    in reply to: Anchor Handling Stability #38343
    Sharat Jami
    Participant

    Thanks Mr Jurgen for your opinoin,

    However i was reading the IMO 55 SLF session, where IMO are considering to amend the part B of IS Code 2008, they are proposing to implement new regulations for towing, lifting and anchor handling operations in the Second generation stability code. It was initially proposed by the Norwegians, to which all the subcommittee members encouraged and subcommittee is most likely to be accepted.

    Maybe in the coming year we will have this as Second Generation Intact Stability Criteria. a complete set of new regulations,
    check out the proposed ammendments

    MSC96-3-1-AmendmentstotheintroductionandpartBoftheInternationalCodeonIntactStability2Secretariat.pdf

    in reply to: Anchor Handling Stability #38340
    Sharat Jami
    Participant

    Hi Maarven,

    I did not understand what exactly is another direction??

    in reply to: Calculations stability #38336
    Sharat Jami
    Participant

    I think its a classic mix up which everybody experiences for the first time when they execute stability on any software.

    The major idea of stability depends on buoyant hull which is considered, if there are any openings on the hull, the stablity GZ curve stops at that particular angle where the point gets immersed.

    I am showing a case study for better explanation which was executed in Freeship GPL software. which is primitive version of Delftship.

    A Box of dimensions L=21 m,B=5.9 m,D=1.5 m is submerged for a draft T = 0.5 which corresponds to Disp = 63.499 T,
    stability is assessed for 2 cases. for constant draft/disp.

    Case-1: Deck Surface closed.
    DeckClosed.png
    GZ curve comes as follows:
    GZDeckClosed.png

    Case-2: Deck Surface Open
    DeckOpen.png
    GZ curve comes as follows: you can actually see a sudden collapse in GZ, that is because at that angle the water starts flooding inside thus changing the displacement, hence here a much advanced concept of dynamic stability including ingress of water is applied to predict stability.
    GZDeckOpen.png

    Normally when performing intact stability check the body which is floating needs to be completely enclosed, a complete enclosure can be checked by an option called check model in delft ship. if leak points are observed your hull is open to flooding.

    I hope i have solved the issue.

    in reply to: Stability Problems #38214
    Sharat Jami
    Participant

    Hello Ifuchs,

    I hope this shall give you an idea about how the righting arm curve of a beamy hull and an narrow hull looks like
    Slide12.gif

    you can also see the comparision for different kind of hullforms
    ConstWidthPlus.gif

    So in your case the hull is pontoon, i.e it has high initial stability, but it shall last for only upto 10 – 15 deg, after that there is a consistent, decrease in GZ value and it vanishes around 40-45 deg i.e you, so these kind of vessels will be best suited for coastal water operations.

    the more wider you make the more stiff the vessel will become. so your max GZ value will increase at same lesser angle
    ,
    I have simulated your case kindly refer the GZ curve comparisions i have found.
    CASE-1: Width 30 m
    Screenshotfrom2016-03-2601-22-59.png

    CASE-2: Width 20 m
    Screenshotfrom2016-03-2601-24-27.png

    CASE-3: Width 10 m
    Screenshotfrom2016-03-2601-27-18.png

    I hope i must have clarified.

Viewing 9 posts - 1 through 9 (of 9 total)