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Thread: C-Lung question.

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    RBW Member 1982shawn is an unknown quantity at this point 1982shawn's Avatar
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    C-Lung question.

    Over the weekend I got to try a rebreather in the pool for the first time. The unit was a rEvo mini. While swimming around it was great the moment I went from horizontal to kneeling on the bottom it became about 5 times as hard to exhale. I asked the instructor about this, they suggested that the counter lungs may be to small for my size(I'm a big guy with big lungs). Can anyone shed some more light on this, I didn't find much searching online.

    Secondly I have been debating between a Meg as first choice and a rEvo as second. After this weekend, if the CLung size is a big factor I think I'm sold on a Meg with 7liter OTS CLungs. Thoughts?

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    RBW Member Pat O'Brien is an unknown quantity at this point Pat O'Brien's Avatar
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    Re: C-Lung question.

    Hi,
    Did your instructor explain minimum loop volume? if not you could have had the counterlungs overfilled.

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    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: C-Lung question.

    I find with back mounted counterlungs posion on the body, orientation of the body and lung volume all have a huge effect on WOB. Front mounted counterlungs just seem to work in all positions.
    Cheers,

    Dave....

    www.wedivebc.com

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    RBW Member 1982shawn is an unknown quantity at this point 1982shawn's Avatar
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    Re: C-Lung question.

    Quote Originally Posted by Pat O'Brien  View Original Post
    Hi,
    Did your instructor explain minimum loop volume? if not you could have had the counterlungs overfilled.
    They did explain minimum loop volume. I felt like it was correct while horizontal but once vertical it felt like there was to much in the loop. Any explanation for this, something I may have missed? While horizontal my buoyancy was great no bouncing in the water column.

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    RBW Member 1982shawn is an unknown quantity at this point 1982shawn's Avatar
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    Re: C-Lung question.

    Quote Originally Posted by wedivebc  View Original Post
    I find with back mounted counterlungs posion on the body, orientation of the body and lung volume all have a huge effect on WOB. Front mounted counterlungs just seem to work in all positions.
    Thanks. I've read the same in a few different places, another point driving me to the meg.

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    Hammermeg, Copis2, Kiss divingabe is just really nice divingabe is just really nice divingabe is just really nice divingabe is just really nice divingabe is just really nice divingabe is just really nice divingabe is just really nice divingabe is just really nice divingabe is just really nice divingabe is just really nice divingabe is just really nice divingabe's Avatar
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    Re: C-Lung question.

    It was most likely due to Hydrostatic pressure.
    WOB is greatly affected by the position of the c-lung
    to your lungs.
    When in a upright or head down position on backmounted
    lungs the water pressure pushes the bubble up making hard
    to exhale and on head down making it hard to inhale.
    top of the shoulder back and front over the shoulder mounted lungs pretty much
    negate the hydrostatic effect.
    Gabe
    Last edited by divingabe; 22nd March 2016 at 21:17.

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    RBW Member whynot? will become famous soon enough whynot? will become famous soon enough whynot? will become famous soon enough whynot? will become famous soon enough whynot?'s Avatar
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    MK15.5, MK25

    Re: C-Lung question.

    Quote Originally Posted by 1982shawn  View Original Post
    Over the weekend I got to try a rebreather in the pool for the first time. The unit was a rEvo mini. While swimming around it was great the moment I went from horizontal to kneeling on the bottom it became about 5 times as hard to exhale. I asked the instructor about this, they suggested that the counter lungs may be to small for my size(I'm a big guy with big lungs). Can anyone shed some more light on this, I didn't find much searching online.

    Secondly I have been debating between a Meg as first choice and a rEvo as second. After this weekend, if the CLung size is a big factor I think I'm sold on a Meg with 7liter OTS CLungs. Thoughts?
    I'd contact rEvo and see what they offer as far as CL size. I dive both back CL (BMCL) and chest CL, each has it's advantages and disadvantages. The big question you should be thinking about is what is your goal with either OTSCL or BMCL? I'll point out one big advantage to BMCL is the fact that they are captured in a compartment (as you no doubt have seen) and are more protected from being damaged that OTSCL. But as others have pointed out the WOB needs to be understood as well. Look at Bozanic's book for a discussion on the benefits/ disadvantages of both- he has spelled it out quite well.

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    RBW Member jlovold is a jewel in the rough jlovold is a jewel in the rough jlovold is a jewel in the rough jlovold is a jewel in the rough jlovold is a jewel in the rough jlovold is a jewel in the rough jlovold is a jewel in the rough jlovold's Avatar
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    Re: C-Lung question.

    I believe the mini has something like 7l counterlungs. Much more than most people can exhale from their lungs.

    I have the micro, which I like due to the small counterlung, which is more or less exactly the size of my lungs.

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    RBW Member 1982shawn is an unknown quantity at this point 1982shawn's Avatar
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    Re: C-Lung question.

    Quote Originally Posted by whynot?  View Original Post
    Look at Bozanic's book for a discussion on the benefits/ disadvantages of both- he has spelled it out quite well.
    Thanks! I will definitely look into that.

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    RBW Member 1982shawn is an unknown quantity at this point 1982shawn's Avatar
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    Re: C-Lung question.

    Quote Originally Posted by divingabe  View Original Post
    It was most likely due to Hydrostatic pressure.
    WOB is greatly affected by the position of the c-lung
    to your lungs.
    When in a upright or head down position on backmounted
    lungs the water pressure pushes the bubble up making hard
    to exhale and on head down making it hard to inhale.
    top of the shoulder back and front over the shoulder mounted lungs pretty much
    negate the hydrostatic effect.
    Gabe


    Thanks, that's what I've been reading and hearing from others. Pretty sure OTS is the way I'll be going now.

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