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Next step for longer bottom times on deep dives?

Discussion in 'Technical Diving' started by jf3193, Apr 20, 2021.

  1. wetb4igetinthewater

    wetb4igetinthewater Instructor ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: Seattle
    No, I don't think they are necessarily ignorant. If they say they understand that they understand the increased risks with narcosis in an emergency situation when exceeding a density of 6.2 g/L and accept those risks, I'm good with that. I'm not good with people who dismiss the science. I have had a conversation with one individual who dismissed Dr. Mitchell as "just an occasional diver" who trusts the divers at his former dive center who "regularly" dive to 70 meters or more on air. A friend of mine in Europe is friends with a number of people who died diving that way. And they don't switch to trimix until 100 meters. Now obviously there is a big gap between 40 and 100 meters on air. However, the risks increase dramatically above a gas density of 6.2 g/L. That's ultimately my point. It does come down to risk assessment, and we all assume different levels of risk. But I'll never understand or respect those who dismiss science.
    Searcaigh likes this.
  2. jf3193

    jf3193 Contributor

    # of Dives: 100 - 199
    Location: Usa
    thanks! Most of the 'deep' stuff I do tends to be in the 90-110 range. Nothing that can't be done on a good EAN, but always wishing I had more, since I have really good air consumption, even at those depths.
  3. jf3193

    jf3193 Contributor

    # of Dives: 100 - 199
    Location: Usa
    it usually kicks in around 110 for me so that I notice. Id still like to stay 'longer' in that 90-100 range than the EAN 30-32 allows.
  4. jf3193

    jf3193 Contributor

    # of Dives: 100 - 199
    Location: Usa
    South Carolina. Looking to get into the North Carolina wrecks more frequently, which are often in that 90-120 range.
  5. jf3193

    jf3193 Contributor

    # of Dives: 100 - 199
    Location: Usa
    Thats really what I was trying to find the solution for, I guess I just wrote it out incorrectly. Im still wanting to stay in 'recreational range' just extend my bottom time somehow.
  6. Marie13

    Marie13 Great Lakes Mermaid ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Great Lakes
    Mine kicks in about 115-120'. You're going to need deco training to stay longer at those depths.
  7. Blackfrogfeet

    Blackfrogfeet Registered

    # of Dives: 500 - 999
    Location: Canada
    I see guys say that a lot but isn't that mentality a little bit of a hold over from the days where CCRs were a lot less reliable, a lot higher risk, and the only people using them were doing exploration dives?

    In my neck of the woods, I see CCR guys doing rec profiles and basic tec profiles (40-50m with 30-40min deco) all the time. Of course those dives could be done on OC very easily. I see guys diving CCRs on 15m/60 minute rec dives a lot, but they need to be doing those dives with their CCR so they can maintain proficiency so that when they go do a 75m dive, their skills are sharp.

    I'm going CCR very soon, and the primary driver for that is Helium, but I fully intend to dive my rebreather on most of my rec dives as well to get hours on the unit, and avoid maintaining unnecessary sets of doubles and regs that I won't need because I'll have a CCR. And even on rec dives, 5lb of sorb is cheaper than a doubles nitrox fill ($35) so it will save me a lot in the long run.
  8. ginti

    ginti DIR Practitioner

    # of Dives: 200 - 499
    Location: Lyon, France
    Like it or not, the more "scientific" approach is not to follow one person's recommendations. Instead, follow the entire scientific community. A single individual, even if very knowledgeable, can make mistakes. The entire community too, but it's more unlikely. :)

    The fact that it is not mentioned doesn't mean that it didn't play a role. Maybe all of these people would be alive if they were breathing trimix; who knows? The only thing that we know for sure is that the scientific community recommends avoiding narcosis. And scientists of today know more than you, more than me, and more than the people who made reports on the deaths you mentioned.

    Did you ever think that these dives have been historically done in air/nitrox just because 20-30-40 years ago scientists knew less than today, and were giving recommendations according to their more limited knowledge? And that limited technology also played a role in those choices?
    jf3193 and grantctobin like this.
  9. Wibble

    Wibble Contributor

    # of Dives: 500 - 999
    Location: UK

    Large entry cost in terms of finance and commitment -- think motorcycle. Once over that, it's amazing, cheap to run and flexible.

    Failing that it's a twinset, stages and learning decompression procedures.

    Other agencies factor in your future, not PADI.
    rsingler and jf3193 like this.
  10. happy-diver

    happy-diver Skindiver Just feelin it

    # of Dives: 2,500 - 4,999
    Location: Same ocean as you!
    Well, dive 36
    jf3193 likes this.

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