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Thread: Inquest verdict from Jersey Channel islands UK

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    Supporting Member darushin is an unknown quantity at this point darushin's Avatar
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    Re: Inquest verdict from Jersey Channel islands UK

    Quote Originally Posted by wedivebc  View Original Post
    I don't know what unit was involved but let's say it was a P2 should we not look at modifying design of the unit to ensure something like this can not happen again?
    Sure we can blame the diver and it looks like there is quite a bit of blame we can assign to the diver but does it end there?
    It should not be too difficult to design rebreather loop that can not possibly create a scubber bypass by incorrect installation.
    As long as the mushroom valves are unidirectional and can't be interchanged it won't bypass the scrubber.
    Heck the original meg could be configured to go either way but as long as you had one muchroom valve in each end of the DSV it worked.
    The way the unit has been reported as being assemble, it would be impossible to function and take some damn serious work to achieve. Mounting the lungs backwards alone would not do it. The scrubber should still scrub as the air would go from outside to inside in the canister instead of inside to outside. The fatal flaw was putting the DSV/BOV on the hose in a way that caused the exhale and inhale mushroom valve to be on the same side. However the pre-breath should catch this as the unit should be un-breathable.

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    Re: Inquest verdict from Jersey Channel islands UK

    Quote Originally Posted by silent running  View Original Post
    Hello Omission, nice handle, I need to know more. Never mind the hose/head connection threads, I don't see how you could switch the CLs and still have the LP hoses reach the manual add/adv and O2 man add buttons, doesn't make sense, not physically possible in any way I can see... -Andy
    Maybe, but lets say it is possible and the LP's match up (I don't know, don't dive a PRISM 2 but like you had the TOPAZ). You'd be putting the O2 feed onto an ADV. That alone would kill you on descent if you didn't catch it.

    Quote Originally Posted by darushin  View Original Post
    The way the unit has been reported as being assemble, it would be impossible to function and take some damn serious work to achieve. Mounting the lungs backwards alone would not do it. The scrubber should still scrub as the air would go from outside to inside in the canister instead of inside to outside. The fatal flaw was putting the DSV/BOV on the hose in a way that caused the exhale and inhale mushroom valve to be on the same side. However the pre-breath should catch this as the unit should be un-breathable.
    Yea, this sounds kind of odd. I don't think it's even possible to put two mushroom valves on the same side. Maybe someone can weigh in on this unit specifically but I can't imagine it being the case. You're options would have to be leave one out (which would be harder to catch if you didn't pre-breath) or put one in backwards (which would make it impossible to inhale or exhale depending on which direction they face).

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    Supporting Member darushin is an unknown quantity at this point darushin's Avatar
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    Re: Inquest verdict from Jersey Channel islands UK

    Quote Originally Posted by tmccar1  View Original Post
    Maybe, but lets say it is possible and the LP's match up (I don't know, don't dive a PRISM 2 but like you had the TOPAZ). You'd be putting the O2 feed onto an ADV. That alone would kill you on descent if you didn't catch it.



    Yea, this sounds kind of odd. I don't think it's even possible to put two mushroom valves on the same side. Maybe someone can weigh in on this unit specifically but I can't imagine it being the case. You're options would have to be leave one out (which would be harder to catch if you didn't pre-breath) or put one in backwards (which would make it impossible to inhale or exhale depending on which direction they face).

    If the DSV is in normal working condition, with good valves and factory hoses, you can't. The dsv hoses are keyed to prevent this. Also, while not keyed,in the BOV the mushroom valves sit in the BOV (one on each side) and trying to put two on the same side would be pretty obvious as there would be no where to attach the valve.

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    Supporting Member darushin is an unknown quantity at this point darushin's Avatar
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    Re: Inquest verdict from Jersey Channel islands UK

    Quote Originally Posted by wedivebc  View Original Post
    I don't know what unit was involved but let's say it was a P2 should we not look at modifying design of the unit to ensure something like this can not happen again?
    Sure we can blame the diver and it looks like there is quite a bit of blame we can assign to the diver but does it end there?
    It should not be too difficult to design rebreather loop that can not possibly create a scubber bypass by incorrect installation.
    As long as the mushroom valves are unidirectional and can't be interchanged it won't bypass the scrubber.
    Heck the original meg could be configured to go either way but as long as you had one muchroom valve in each end of the DSV it worked.

    The prism 2 should work similar. I put my BOV on backwards and I remember it breathing hard during pre-breath and sensor readings that didn't make sense. However the thing that gets me is the face to face mushroom valves. The unit would not breathe at all in the config.

    Daru

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    Re: Inquest verdict from Jersey Channel islands UK

    Quote Originally Posted by darushin  View Original Post
    The prism 2 should work similar. I put my BOV on backwards and I remember it breathing hard during pre-breath and sensor readings that didn't make sense. However the thing that gets me is the face to face mushroom valves. The unit would not breathe at all in the config.

    Daru

  6. #26
    Mature mouth breather silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running's Avatar
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    Re: Inquest verdict from Jersey Channel islands UK

    Quote Originally Posted by tmccar1  View Original Post
    Maybe, but lets say it is possible and the LP's match up (I don't know, don't dive a PRISM 2 but like you had the TOPAZ). You'd be putting the O2 feed onto an ADV. That alone would kill you on descent if you didn't catch it.
    Hello Tim, if you remember, on the P1 it is not possible to attach O2 LP hose to the inhale CL as it has a different fitting, sort of like one of those big Scubapro BC inflators, while the dil add/adv is a regular LP sleeve fitting. Simple and foolproof, never mid the LP hose routing.

    My guess is that the P2 may have something similar, as I don't know why they would deliberately take a step backwards safety wise. But I still really can't see how you could cross over those LP lines AND still reach the adv and O2 add fittings without one's whole chest area being very constricted and uncomfortable... -Andy

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    Re: Inquest verdict from Jersey Channel islands UK

    Quote Originally Posted by darushin  View Original Post
    The prism 2 should work similar. I put my BOV on backwards and I remember it breathing hard during pre-breath and sensor readings that didn't make sense. However the thing that gets me is the face to face mushroom valves. The unit would not breathe at all in the config.

    Daru
    Not quite. What would happen is that you would breathe in and out of the same loop hose, rather than having any kind of one-way flow. Someone on SB actually tried recreating the supposed failure condition with their P2 and confirmed that you get a screwed-up unit that's basically the same as breathing in and out of a paper bag: http://www.scubaboard.com/forums/acc...ml#post7282948

  8. #28
    Mature mouth breather silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running has a reputation beyond repute silent running's Avatar
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    Re: Inquest verdict from Jersey Channel islands UK

    Just curious, can someone who owns a P2 confirm whether or not the O2 and dil lp hoses have the same fittings on the CL ends? Thanks, -Andy

  9. #29
    Dave Tomblin wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc's Avatar
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    Re: Inquest verdict from Jersey Channel islands UK

    Quote Originally Posted by darushin  View Original Post
    The prism 2 should work similar. I put my BOV on backwards and I remember it breathing hard during pre-breath and sensor readings that didn't make sense. However the thing that gets me is the face to face mushroom valves. The unit would not breathe at all in the config.

    Daru
    If you put both mushroom valves on the same side the gas will flow effortlessly to and from the same hose. The diver will be unaware there is a problem until they start to feel the effects of the CO2
    With the Hollis BOV this can't happen BTW because the mushroom valves are both fixed to the BOV and are not interchangeable.
    Cheers,

    Dave....

    www.wedivebc.com

  10. #30
    Dave Tomblin wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc has a reputation beyond repute wedivebc's Avatar
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    Re: Inquest verdict from Jersey Channel islands UK

    Quote Originally Posted by silent running  View Original Post
    Just curious, can someone who owns a P2 confirm whether or not the O2 and dil lp hoses have the same fittings on the CL ends? Thanks, -Andy
    yes they do

    Having said that running the CLs on the wrong side would be an inconvenience when you went to add dil but not a fatal mistake. Not having directional flow through the DSV is.
    Cheers,

    Dave....

    www.wedivebc.com

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