Deck below waterline

Discussion in 'Class Societies' started by sushkin, Jan 23, 2017.

  1. sushkin
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    sushkin Junior Member

    Hello everyone.
    There is 6m boat that has to satisfy ISO requirements, but its deck is below waterline in maximum load condition (pic1)
    [​IMG]
    There are several options in ISO standarts for non qiuck draining cockpit.
    6.5.4 ISO 12217-1 says Recesses fitted to design category C boats using option 6 (pic2)
    [​IMG]
    having a volume to retention level larger than (LHBHFM)/40, entirely contained within LH/2 of the bow shall either be quick-draining (overboard) or drain to the bilge in the same time or less.

    The cockpit is lager then (LHBHFM)/40. Then I briefly calculated the time needed for draining and it was clear that bildge pump cannot provide such draining speed. As I understood #6 is not an option for this boat.

    Choosing option 4 (pic2) means passing flotation test with flotation materials according Annex G.
    Maybe someone knows if there are any other options to avoid flotation materials? Because it would be qiute difficult to organize a foam inside the boat.

    Thanx
     
  2. TANSL
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    TANSL Senior Member

    For what you say, and without knowing the boat, I think you have no choice but to reduce the weight to full load and decrease the volume of the cokpit : place the floor over the waterline and place a double hull, watertight, of the required width.
     
  3. Mr Efficiency
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    Mr Efficiency Senior Member

    What is the "flotation test" that it has to pass ? Can you not install a bigger bilge pump, or perhaps two ?
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    Six metres is marginal for a self-draining cockpit, unless the boat is beamy and broad shouldered, imo.
     
  5. sushkin
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    sushkin Junior Member

    The deck is FRP and the mold is finished. Even if making a new mold for the deck with higher floor level (100-130mm), the boat is supposed to have a wheelhouse, it will ruin all the design, it might be neccessary to raise up the board also or something. Not much fun
     
  6. sushkin
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    sushkin Junior Member

    ISO says it's neccessary to heel the boat (with crew and passengers imitating weights) so the coaming sinks into the water, wait till the water equilibrates and then release the boat.
    Concerning pumps, I do not remember exactly, but the draining speed should be much more out of the range of pump perfomance
     
  7. Mr Efficiency
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    Mr Efficiency Senior Member

    That sounds unscientific and ridiculous to me, bureaucracy gone mad. The behaviour of the crew/passengers could be the determining factor, in a real life situation they'd likely be tossed out of the boat.
     
  8. TANSL
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    TANSL Senior Member

    Even if the mold is finished, you can modify it to raise the floor.
    Put a watertight seal in the cockpit so that its volume is not counted as belonging to the cockpit.
    You can put, I suppose, two bilge pumps, with two different outlets.
     
  9. sushkin
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    sushkin Junior Member

    If you mean partially raise the floor and put a seal in front of the wheelhouse (so the wheelhouse height is not changed) that might be a good idea but when there is no wheelhouse there would be strange looking step
     
  10. TANSL
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    TANSL Senior Member

    Yes, I mean that.
    What about 2, or three, bilge pumps?
     
  11. Barry
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    Barry Senior Member

    I am wondering if this is in fact applicable.

    Your statement "retention level larger than Volume/40 , ENTIRELY contained within the LH/2 of the BOW shall be either quick draining or drain to the bilge.

    I would interpret this as if you have a recessed volume completely separate from any other part of the boat in the front half of the boat , Ie "contained within the LH/2 of the bow" that it has to be drained overboard or to the bilge.

    Perhaps a boat that might have a separate seating area, open bow rider or any other "entirely contained recess" within the front half of the boat might be where this standard applies

    Maybe they are just trying to ensure if you take 1,000 pounds of water over the front of the boat into a separate recess, that you can get rid of it through drains or into the bilge where it can get pumped out
     
  12. sushkin
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    sushkin Junior Member

    Sounds more strange but I will submit this to a manufacturing conference)
    Thanx)
     
  13. TANSL
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    TANSL Senior Member

    The regulations establish the minimum number of pumps, bilge pumps or fire pumps, but not their maximum number.
     
  14. sushkin
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    sushkin Junior Member

    I would be happy if quick draining cockpit was not mandatory. But there is nothing said about separate or not separate, I interpret this as - volume in the bow should be quick draining or with huge pupms (because there is no space for the bildge in that boat). As stern and bow volumes are uniform, so they have to be self draining.
     

  15. Mr Efficiency
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    Mr Efficiency Senior Member

    Why wasn't all this factored in at the design/build stages ?
     
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