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Reconsidering Deep Air?

Discussion in 'Technical Diving' started by CAPTAIN SINBAD, Mar 23, 2021.

  1. OTF

    OTF Contributor

    # of Dives: 200 - 499
    Location: scubaboard
    600
    801
    The risk comparison between rebreather trimix and deep air (if those are your options) is an interesting conversation, and maybe a more valuable debate than deep air vs. OC trimix.
     
  2. mac64

    mac64 Contributor

    # of Dives: 5,000 - ∞
    Location: Ireland
    906
    650
    I don’t know how narcosis or gas density affects other people, like they said on the video it depends on the individual. People should watch the video and ask themselves is there something to learn. Obviously there’s a difference of 30 metres between 30and 60. but where narcosis or density is concerned, for me there’s no difference. In fact some 30 metre dives can be more challenging than 60 metres depending on the conditions. I could count on one hand the amount of buddy dives I’ve done. My dives have been with a standby on the surface or solo.
     
    johndiver999 likes this.
  3. helodriver87

    helodriver87 DIR Practitioner

    # of Dives: 500 - 999
    Location: New Mexico
    480
    851
    That's a really high incidence rate for a supposedly small group of personal acquaintances. If that's an accurate number, I'd be really curious to know the specifics (unit, training, sites, experience, etc). Seems to me that goes beyond the inherent risk increase of CCR diving and even bad luck.
     
  4. Wibble

    Wibble Contributor

    # of Dives: 500 - 999
    Location: UK
    1,002
    749
    Sorry; edited. Meant hypERoxic mix

    e.g. not 21% at 45m (140') but 25%. Has an impact on deco time, but not as much as using proper deco gasses.
     
    mac64 likes this.
  5. Wibble

    Wibble Contributor

    # of Dives: 500 - 999
    Location: UK
    1,002
    749
    Couple of things about deeper air.

    Had a 'pot dive' in a recompression chamber a few years back. Really interesting how it affects everyone. It was only to 40m/125' with a group of 8 divers. First thing I noticed was we were all giggling like a bunch of schoolgirls, quite odd. Were given some simple tasks to do on the bottom - add some numbers, name a river beginning M, nothing hard. When on the surface I couldn't read my writing and managed to get several wrong!

    Basically it's like drinking more beer. A pint (half litre, 20 fluid oz...) for each 10 metres/30'. So we were giggling like we'd had 4 pints, probably about right. From my own experience of diving on deep air, getting to 50m/160' seems like you've drunk 6 pints; definitely getting proper squiffy. Worse than beer, it's becoming paranoid and you easily object/task fixated and loose your memory. Staring at the SPG and computer, but not reading it...

    When we all jump into a car after having drunk, say 5 pints. Driving the car's easy because it's all unconscious competence or muscle memory. But we're absolutely not safe. We might get home, but we have a much higher chance of not getting home. One of the reasons why it's illegal; doesn't do to kill people because we're drunk.

    With diving it's the same. We rely on our honed experience but narcosis does affect us. The worse part is it's unnoticed; we don't realise we're narked and potentially in peril.

    Of course the more experienced people are far more aware of the issues, so it's possible to mitigate the affects to a point. Basically be slow and don't be brave.
     
    OTF likes this.
  6. DiveClimbRide

    DiveClimbRide Instructor, Scuba

    # of Dives: 200 - 499
    Location: New Zealand, South Island
    161
    97
    While not 300/cuf, helium here is around (usd) 6/cuf or (nzd) .30/l
     
  7. grantctobin

    grantctobin ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: Chicago
    1,036
    725
    Yeah, have seem the same USD0.30/L in parts of the US Midwest (WI, MN), depending on the source. I don't disagree that it's expensive. Sinbad's "add two zeroes" is the delusion. Kia Ora.
     
  8. DiveClimbRide

    DiveClimbRide Instructor, Scuba

    # of Dives: 200 - 499
    Location: New Zealand, South Island
    161
    97
    Perhaps he was thinking of the total gas bill. Doubling could add one zero but not two.
     
  9. CAPTAIN SINBAD

    CAPTAIN SINBAD Divemaster Candidate

    # of Dives: 200 - 499
    Location: Woodbridge VA
    2,916
    1,078
    Allow me to take you out of your economic bubble for a moment. The last time I checked, cost of Helium in Pakistan was not that different that what we have here in the US. Here is what that means for someone who is a local technical diver over there.

    1 USD = 155 PKR.

    Most people who dive in Pakistan are the young men and women who have just started a career and are making 100,000 PKR a month. That comes to 645 USD a month which is pretty decent salary for the local economy and buys you a decent life there but helium is prices are not part of that local economy. Imagine if you went to your LDS and each fill was half of your monthly salary then realistically as a technical diver you will have two options...

    a) Stop technical diving
    b) Dive deep air to a depth where your own sensibilities make it seem safe to you! (Whatever that may be.)

    Which of the above would you choose?

    I personally love GUE/UTD Standard gases but due to helium availability and costs, that style of diving has zero appeal in many parts of the world where people still dive. They would be more eager to take the TDI Extended Range course or PSAI Narcosis Management levels than Tech-1.
     
    shoredivr and Lostdiver71 like this.
  10. CAPTAIN SINBAD

    CAPTAIN SINBAD Divemaster Candidate

    # of Dives: 200 - 499
    Location: Woodbridge VA
    2,916
    1,078
    Three of those fatalities have been discussed here on these forums. The fourth one was an international incident that never made it on scubaboard. I do not know the units and the circumstances at the top of my head but we can browse through fatalities on scubaboard and those that could be attributed to deep air are less than those that can be attributed to CCR. Since there is more money to be made by the latter, weight of political correctness is also behind CCRs at this time.
     

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