oscillatory bailing

Discussion in 'Hydrodynamics and Aerodynamics' started by lucdekeyser, Jun 9, 2014.

  1. lucdekeyser
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    lucdekeyser Senior Member

    lucdekeyser, Jun 9, 2014
    #1
  2. daiquiri
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    daiquiri Engineering and Design

    Kids are sometimes really incredible! :)

    That technique works, imo for three reasons:
    1. the boat floats when filled with water
    2. the cross-section shape of the bilge looks like a circular arc to me, or is very similar to a circular arc - hence good for allowing an unobstructed and smooth motion of the water.
    3. the size and inertia of the boat are sufficiently small to allow the crew (just one small girl, in this case) to oscillate the hull at the resonant frequency of the bilge water, thus synchronizing the water motion on such way to let mass inertia do the work of pushing it out of the bilge.
    Hence, IMO, it can be applicable in those limited number of cases where similar conditions exist.
    Thanks for sharing this video, it was very instructional. :)

    Cheers
     
    daiquiri, Jun 9, 2014
    #2
  3. Mikko Brummer
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    Mikko Brummer Senior Member

    Here's a good simulation challenge, free surface & sloshing! Some similarity with the 470 in the aquarium I just posted.
     
    Mikko Brummer, Jun 9, 2014
    #3
  4. JSL
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    JSL Senior Member

    Works on very small boats ( I have done it many times) & canoes but not for large boats since the free surface effect could capsize the boat.
     
    JSL, Jun 9, 2014
    #4
  5. Doug Lord
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    Doug Lord Flight Ready

    Doug Lord, Jun 9, 2014
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  6. Mr Efficiency
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    Mr Efficiency Senior Member

    Don't think it would be a safe place to be in something oscillating like that, you could become the baby that got thrown out with the bath-water.
     
    Mr Efficiency, Jun 9, 2014
    #6
  7. JSL
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    JSL Senior Member

    Works on very small boats ( I have done it many times) & canoes but not for large boats since the free surface effect could capsize the boat.
    Update: In scouts and sea cadets we were taught this system in the event of capsize. One person would be on each gun'l and while still in the water alternately pull/push down to get the boat rocking. The water would slosh out port/stbd. You might remove about 50% but by that time you could re-board (carefully) and finish off with a bailer.
    Boats need positive floatation, should have a bit of freeboard when swamped (about 10% of the beam), and not too much clutter.
     
    JSL, Jun 9, 2014
    #7
  8. lucdekeyser
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    lucdekeyser Senior Member

    How was this technique called?
     
    lucdekeyser, Jun 12, 2014
    #8

  10. JSL
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    JSL Senior Member

    I don't recall. "Rocking Bailing" perhaps
     
    JSL, Jun 12, 2014
    #9
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