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Any value sucking on your EAN tank during ride back to the dock?

Discussion in 'Advanced Scuba' started by hsinhai, Apr 26, 2021.

  1. BRT

    BRT not a soft touch

    Could be.
  2. sea_ledford

    sea_ledford Captain

    # of Dives: 2,500 - 4,999
    Location: Galveston, TX
    Ugh! I bet they stopped doing that after the first time it didn't work.

    Cleaning puke out of a reg is the worst. Nope... cleaning someone ELSES puke out of a reg is the worst.

    Scratch that, cleaning someone else's puke out of a reg that wasn't in the water when it happened would be the worst!
    eleniel and RyanT like this.
  3. formernuke

    formernuke ScubaBoard Sponsor ScubaBoard Sponsor

    # of Dives: I just don't log dives
    Location: New England
    Not at vomiting stage of it.
  4. ofg-1

    ofg-1 Course Director

    Not back to the dock, all the way home. It really freaks out other drivers to see someone breathing off a scuba tank while driving, especially if you wear your mask. Also, if the cops stop you, you can breathe like Darth Vader.
    sabbe, pauldw, Hoyden and 5 others like this.
  5. beester

    beester DIR Practitioner

    # of Dives: 1,000 - 2,499
    Location: Belgium / Italy
    Sorry BRT, I can't give any meaningful comment on this, because I wasn't aware of DCS incidents after a computer got stuck in nitrox mode on the surface. I can only assume that this might affect your surface interval and subsequent NDL on a 2nd dive. It is never a good idea to use a deco gas to reduce the surface interval for a 2nd dive.

    What I'm saying is that breathing a decogas on the surface allows a bigger N² pressure gradient in your body and bloodstream, which will speed up the off gassing and reduce the formation of bubbles in the immediate period after surfacing. the PPN² on the surface is 0.78 bar, if you breath O² it is 0 bar. I'm saying that in this regard the effect of for example Nitrox 32 is negligable because it doesn't affect the pressure gradient as much (you still will be breathing a gas with PPN² 0.66 bar).

    After serious deco dives it is not uncommon to keep breathing O² on surfacing for at least another 30 minutes. I would not do that with nitrox 32, because I would never carry that as a deco gas (it's not efficient) and as such it would be backgas... if I'm breathing 32% as backgas, it probably is a recreational dive... no need to breath anything on the surface but Gods own nitrox (air).
    hsinhai and OTF like this.
  6. happy-diver

    happy-diver Skindiver Just feelin it

    # of Dives: 2,500 - 4,999
    Location: Same ocean as you!
    Yeah, especially for the hangover induced type, it works absolutely wonderfully amazingly

    Man, be an alert driver and when you see them plop it out of your mouth next to your beer
  7. TMHeimer

    TMHeimer Divemaster

    # of Dives: 500 - 999
    Location: Dartmouth,NS,Canada(Eastern Passage-Atlantic)
    This is the first I've heard of breathing nitrox when you don't suspect DCS. Nitrox 32 is only 11% more O2 than air, so I would guess it helps very little. I know it is advised for DCS patients if you run out of O2.
    Bob DBF likes this.
  8. GJC

    GJC Solo Diver

    # of Dives: 200 - 499
    Location: Southern California, USA
    I think I read that too about using it if you ran out of O2 but can't remember where. You remember where that was from?
  9. OTF

    OTF Contributor

    # of Dives: 200 - 499
    Location: same ocean as you
    "what would happen if you take off the mask?"

    As others have said already, breathing EAN is definitely better than breathing air in terms of offgassing. The difference is probably quite small - but hey if it's easy why not go for it. Any small thing to reduce decompression stress can't hurt. Breathing pure O2 after serious dives is effective and a real thing that some people do.
    kelemvor and Hoyden like this.
  10. Blackfrogfeet

    Blackfrogfeet Registered

    # of Dives: 500 - 999
    Location: Canada
    Probably best to look at the potential benefits of breathing nitrox on the surface in terms of EAD (equivalent air depth). Using EAN32 as an example : ((0.68 x 1ATA / 0.79) - 1 ATA) x 10 = 1.4 metres ABOVE surface. So would it have an effect? Sure, but how much? I don't think it would be enough to matter.

    Im going to look at it from another angle. If I begin a dive on EAN32, and spend 60 minutes at 2 metres before dropping down to 30m for 35 minutes, my dive profile will require only 1 additional minute of deco vs. conducting only a 30m / 35 minute profile. This was calculated using multideco with 45/85 GF. So 60 minutes of additional on gassing on 32% @ 2m only changed my deco profile by 1 minute.

    So, back to the original question, would breathing EAN32 after the dive benefit you in terms of on gassing? Yes, but it would be very, very insignificant. If you play around with a dive planning software and plug in the same sort of profiles but breathing 50% or 100% in the shallows (effectively off gassing before you even start the dive), you will start seeing actual benefits, but even then, we are talking about less than 5 minute differences in the resulting deco profiles.
    hsinhai likes this.

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