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Thread: How much am I off gassing?

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    Wrecked wrecked is on a distinguished road wrecked is on a distinguished road wrecked's Avatar
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    How much am I off gassing?

    Is it better to swap to a 80% or 100% o2 whilst off gassing on OC due to ease and necessity?
    Last edited by wrecked; 1st September 2014 at 06:00.

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    Fake Diver Jeff Pack will become famous soon enough Jeff Pack will become famous soon enough Jeff Pack will become famous soon enough Jeff Pack will become famous soon enough Jeff Pack's Avatar
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    Re: How much am I off gassing?

    Huh?

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    RBW Member JacobT will become famous soon enough JacobT will become famous soon enough JacobT will become famous soon enough JacobT will become famous soon enough JacobT's Avatar
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    Re: How much am I off gassing?

    I think the answer is. If you dive with trimix the deco might clear slightly faster on OC 80-100% but why on earth would you want to? certainly not "due to ease and necessity"

    If you have a hard time holding your stops, practice practice practice don't complicate things by going OC

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    Re: How much am I off gassing?

    Quote Originally Posted by wrecked  View Original Post
    Is it better to swap to a 80% or 100% o2 whilst off gassing on OC due to ease and necessity?
    Ehh.. Flush and be done with it :)

    In terms of Tx in the loop, you have vented the loop on the ascent and a pO2 of 1.2 will give you an fO2 of 0.75 @ 6m. So why switch to OC? You could even flush it fo go to 1.6 if you have a longer deco obligation.

    Not sure i follow your thoughts here though :)

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    Re: How much am I off gassing?

    Quote Originally Posted by Jeppe_E  View Original Post
    Ehh.. Flush and be done with it :)

    In terms of Tx in the loop, you have vented the loop on the ascent and a pO2 of 1.2 will give you an fO2 of 0.75 @ 6m. So why switch to OC? You could even flush it fo go to 1.6 if you have a longer deco obligation.

    Not sure i follow your thoughts here though :)
    I have not done many deco dives with this unit, only now starting to have bigger runtimes.

    Once I start off gassing I really notice above 10mtrs the amount of inert gas seems to increase dramatically. My buoyancy control is not a big issue as I got this sorted by configuring to ECCR mode on the rEvo though I bob up and down a little between 6-7.5mtrs.

    I am struggling to hold above 1.0 increasing my hang time so I am thinking wouldn't it be more efficient to run most of my 6mtr stop using an OC 90% mix just to be safe which would give me 1.44ppo2 decreasing my deco stop time. I may also do a few more minutes on the breather if I have the time. I know my Shearwater computer can use many gases.
    Last edited by wrecked; 1st September 2014 at 14:21.

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    RBW Member JacobT will become famous soon enough JacobT will become famous soon enough JacobT will become famous soon enough JacobT will become famous soon enough JacobT's Avatar
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    Re: How much am I off gassing?

    Quote Originally Posted by wrecked  View Original Post
    I have not done many deco dives with this unit, only now starting to have bigger runtimes.

    Once I start off gassing I really notice above 10mtrs the amount of inert gas seems to increase dramatically. My buoyancy control is not a big issue as I got this sorted by configuring to ECCR mode on the rEvo though I bob up and down a little between 6-7.5mtrs.

    I am struggling to hold above 1.0 increasing my hang time so I am thinking wouldn't it be more efficient to run most of my 6mtr stop using an OC 90% mix just to be safe which would give me 1.44ppo2 decreasing my deco stop time. I may also do a few more minutes on the breather if I have the time. I know my Shearwater computer can use many gases.
    I am by no means as experienced as many of the members on this forum. But I have yet to notice any significant buoyancy issues that I can attribute to off-gassing (at least nothing that could not be fixed by blowing a few bubbles out of my nose/mask). Even on 100m dives with 2hr+ deco this has (for me at least) not been something I have noticed as being even remotely problematic...

    I am struggling to hold above 1.0
    This has me slightly confused... how and why is that an issue?
    ... and if it is.. should you be doing deco dives just yet??

    -Jacob

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    Re: How much am I off gassing?

    Quote Originally Posted by wrecked  View Original Post
    Once I start off gassing I really notice above 10mtrs the amount of inert gas seems to increase dramatically...
    if this happens it has nothing to do with off gassing, put that idea aside, it's really... not true.

    .. but I know.. you will not believe me anyway, so.. just be happy with the idea...
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    .... radial scrubbers give longer dwell time than axials...
    .... the earth is flat and ...

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    How much am I off gassing?

    Have you checked for a leaky ADV? There is no reason you should have difficulty maintaining either high pO2 or static buoyancy unless gas is leaking in somewhere. Since you took the O2 leaky valve out of the equation, you should check the dil side.

    You shouldn't need dil for ascent. So I'll get myself in more trouble suggesting you could shut down dil during ascent and depressurize the line to see if that helps. But be prepared that you will need to quickly turn it back on if you need to do a dil flush.


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    Re: How much am I off gassing?

    Anyone have any real idea how much inert gas you actually off gas for a given deco dive?
    Are we talking milliliters or litres?

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    Re: How much am I off gassing?

    I have noted with respect to the OPs question, that earlier in my time with eCCR, holding stops at 1.3, above 30ft was very difficult. Now its pretty easy. I can hold a reasonable stop at 15ft now.
    Last edited by Jeff Pack; 2nd September 2014 at 03:01.

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