Inclining Experiment

Discussion in 'Stability' started by Heimfried, Nov 9, 2015.

  1. Heimfried
    Joined: Apr 2015
    Posts: 500
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    Location: Berlin, Germany

    Heimfried Senior Member

    I'm trying to understand a document about an inclining experiment.
    The document ist linked in this posting:
    http://www.boatdesign.net/forums/boat-design/1972-wood-shrimper-54550.html#post756625
    (The link in question is called "Stability Test".)

    To calculate the heel angle the readings of the pendulums corresponding to different conditions of moved loads are added, as it seems to me (page 3, 4, 5).

    May be I misunderstand the procedure of the experiment (movement of loads, "Cambio de Peso").

    The Part of a table below shows three different load conditions. Given are two loads (weights) and only one distance from side to side. Overall are 5 load conditions (neutral not counted) shown.
     

    Attached Files:

  2. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    Nor do I understand how the experience has been made, even though the document is in Spanish and I'm Spanish speaking. However, there are several things that make me wary of that experience:
    - A ship of 80 tons of displacement can not heel a lot with weights of 189 kg.
    - Apparently the weights are moved to different positions each time, which makes the experience not worth at all.
    - I can't understand that, as a pendulum says the ship has heeled an average value of 1,59º while the other pendulum says that the inclination is 3,81º. If the boat is a rigid body, this is not possible.
    So, in my opinion, you do not waste much time studying this document. If I am wrong in my conclusions, I guess the author kindly will correct me.
     
  3. Heimfried
    Joined: Apr 2015
    Posts: 500
    Likes: 115, Points: 43, Legacy Rep: 37
    Location: Berlin, Germany

    Heimfried Senior Member

    It is an amazing ship.

    The transversal shift (5.9 meters) of a load of 0.19 tons causes a heel angle of 1.6 or 3.8 deg.

    According to the "LIBRO DE ESTABILIDAD" of the ship (p. 38) are 70 passengers, 75 kg each, load = 5.25 tons which move 2.5 meters to the side causing a heel angle of 2.6 deg.
     

  4. TANSL
    Joined: Sep 2011
    Posts: 7,109
    Likes: 589, Points: 123, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    The fun is not the ship but study author. And the most fun is that the author is so proud of what he has done that he publishes it in a forum like this to astonish the world with his calculations.We can find rare specimens on this planet.
     
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