Auto Closing Air Vent As Downflooding Point

Discussion in 'Stability' started by naserrishehri, Aug 11, 2013.

  1. naserrishehri
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    naserrishehri Senior Member

    DEAR FRIENDS
    Shall i consider "AUTO CLOSING AIR VENT" on weather deck as down-flooding point while stability calculation?
     
  2. TANSL
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    TANSL Senior Member

    The problem is not whether or not self-closing. Any opening, if it has not a watertight seal, must be considered as a down-flooding point.
     
  3. naserrishehri
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    naserrishehri Senior Member

    what about weather tight doors on upper deck?
     
  4. gonzo
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    gonzo Senior Member

  5. TANSL
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    TANSL Senior Member

    Any opening, not watertight sealed, is a posible down-flooding point.
    For very small openings, according to the Administration, you can request an exception to this rule.
     
  6. athvas
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    athvas Senior Member

    This is what regulation says.........

    "Downflooding angle is an angle of heel at which openings in the hull, superstructures or deckhouses which cannot be closed weathertight immerse. In applying this criterion, small openings through which progressive flooding cannot take place need not be considered as open...."
     
  7. TANSL
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    TANSL Senior Member

    small openings through which progressive flooding can take place need to be considered as open...
     
  8. ontwerp
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    ontwerp Naval Architect

    It depends what you are calculating. For ships designed according to SOLAS:

    When calculating probabilistic damage stability - automatic self closing air vents are considered as down-flooding points.
    When calculating intact stability only unprotected openings need to be considered as downflooding points.
    Exceptions are sometimes made by flag states concerning the watertightness of a ball-type automatic closing air vent, if it has a certificate proving it is watertight at a continuous water column for a sustained amount of time. Example of this is the dutch flag which will allow some of these vents to be considered watertight.
     
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  9. naserrishehri
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    naserrishehri Senior Member

    What about "Exhaust gas pipes openning" shall i consider them as downflooding point?If water goes inside exhaust gas pipes, then water would stop at engine and water can not fill engine room.
     
  10. BlueBell
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    BlueBell Ahhhhh...

    And if the engine is running?
     
  11. JamesG123
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    JamesG123 Senior Member

    You cannot assume that. There are some crank/valve positions (overlap) which would allow water to pass thru cylinders and intake and cause flooding. Or even leak down past rings and flood the crankcase, albeit slowly.
     
  12. naserrishehri
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    naserrishehri Senior Member

    if water can pass through those fittings then smoke also can leak into the engine room.but we don't have smoke leakage in the engine room.
     
  13. JamesG123
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    JamesG123 Senior Member

    Thats not how that works lol.
     
  14. RAraujo
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    RAraujo Senior Member - Naval Architect

    Extract from IMO Code on Intact Stability:
    upload_2019-6-20_8-18-25.png
     

    Attached Files:


  15. rxcomposite
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    rxcomposite Senior Member

    Somewhere along the rules, there is a definition for "weathertight" and "watertight". It seems to be used interchangeably in this thread. Would somebody care to explain?
     
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