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Diving air to 60m

Discussion in 'Advanced Scuba Discussions' started by John Bantin, Jul 17, 2019.

  1. jadairiii

    jadairiii Solo Diver

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    I was pretty much a deep air diver throughout the 90's for petty much the same reason, back then trimix was for dives below 260' (per my Deep Air Instructor) and, like you, the run times were crazy. Again, note that I am referencing back to 1990's knowledge about deep air.

    Then came 1997, I made the mistake of taking a trimix course and it ruined me, because I realized, in one dive, I really wasn't good on air deep! I also learned that my run times on mix were identical to my air dives. (and I actually felt better) Fast forward to 2019 and they (the scientists/Doctors/phd's) seem to agree that helium and N2 are acting about the same as it relates to off-gassing.

    So whatever you do, dont make the same mistake I did and start diving mix!
     
    kensuf, blake7, RyanT and 1 other person like this.
  2. mac64

    mac64 Barracuda

    # of Dives: 5,000 - ∞
    Location: Ireland
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    You sure can twist a persons words.
    I said
    “The notion that you are safer at 60m on a rebreather or trimix than you are on air is a myth. ITS NOT ABOUT THE METHOD ITS ABOUT THE PERSON USING IT.
    Nowhere did I say narcosis is a myth
    I said
    “Hypercapnia is a non issue on open circuit, anyone with any symptoms of carbon dioxide toxicity using open circuit diving gear needs to consult a professional as it is not normal.
    I will stand over everything I’ve said but you will not put words in my mouth
    I’m not the one twisting people’s words here.
     
  3. helodriver87

    helodriver87 DIR Practitioner

    # of Dives: 200 - 499
    Location: Alabama
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    Hypercapnia can absolutely happen on OC. Especially on dense breathing gas at high workload. I can link to studies supporting that if you'd like.
     
    blake7, RyanT and rjack321 like this.
  4. fsardone

    fsardone Solo Diver ScubaBoard Supporter

    # of Dives: I just don't log dives
    Location: Rome, Italy
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    The only time I have got a CO2 hit I was in OC twinset and 3 stages ....
    I was at 12 meters and my instructor showed me what it means to retain CO2.
    To recover I spent 30 minutes on the surface. It is bad and at depth you cannot carry enough gas to overcome it ....
    I disagree fully about not being an issue in OC.
     
  5. mac64

    mac64 Barracuda

    # of Dives: 5,000 - ∞
    Location: Ireland
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    Do you believe you could have prevented it, because if you could then it’s a non issue in my book.
     
  6. mac64

    mac64 Barracuda

    # of Dives: 5,000 - ∞
    Location: Ireland
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    High workload and driving yourself past your limits, that’s poor diving practice and preventable,
     
  7. helodriver87

    helodriver87 DIR Practitioner

    # of Dives: 200 - 499
    Location: Alabama
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    Huh? You can prevent any issue. Don't dive. I'm getting the sense you're one of those who thinks they have absolute control of the situation at all times. You may be in for a rude awakening one of these days. **** happens. And you don't want to be on an inferior gas when it does.
     
  8. helodriver87

    helodriver87 DIR Practitioner

    # of Dives: 200 - 499
    Location: Alabama
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    You know what else can prevent CO2 retention and narcosis? Helium. Which is the whole point of this discussion. Why anyone would dive a gas that only works as long as conditions are controlled and ideal is beyond me. It's comparable to turning a cave dive at half your starting pressure. You have no room for error.
     
  9. mac64

    mac64 Barracuda

    # of Dives: 5,000 - ∞
    Location: Ireland
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    Look everyone is different but for me to drive yourself past your limits and then blame your gear or your mix is like shooting myself in the head and blaming my reg for not diverting the bullet
     
  10. helodriver87

    helodriver87 DIR Practitioner

    # of Dives: 200 - 499
    Location: Alabama
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    The mix is part of the prevention. It's significantly easier to CO2 yourself on a dense breathing gas. You're handicapping yourself with air at that depth and, contrary to what you may believe, you can't guarantee you won't need to work hard at depth. Entanglement comes to mind as a quick example.

    It's like not having a continuous guideline in an overhead or planning your deco to use everything in your cylinder. You'll probably be fine most of the time, but why take a totally unnecessary risk?
     
    pauldw likes this.

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