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Ascent To Altitude From Santa Rosa

Discussion in 'Rocky Mountain Region' started by boulderjohn, Apr 25, 2016.

  1. jvogt

    jvogt ScubaBoard Sponsor ScubaBoard Sponsor

    # of Dives: 200 - 499
    Location: Lakewood, CO USA
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    Sunday I did a 90 minute dive with average depth of 30 ft at ~5500' elevation. I finished the dive with GF99 on my Perdix at about 40%. By the time I was home an hour later GF99 was 0%. About 3 hours after surfacing I rode in a car up to ~8000' elevation while monitoring my Perdix closely. GF99 never moved above 0% and the TLBG for all of the compartments stayed well below ambient pressure the entire time although I did notice them increase slightly.
     
  2. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
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    I have written a brief blog about altitude diving and diving to altitude after diving. You can find it here.

    The main purpose of the blog is to introduce two longer and far more detailed articles, which you can find on my resources page here.
     
    jocamero likes this.
  3. jvogt

    jvogt ScubaBoard Sponsor ScubaBoard Sponsor

    # of Dives: 200 - 499
    Location: Lakewood, CO USA
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    This weekend a group of us where diving in Santa Rosa at Rock Lake. On Sunday we successfully completed a 20 minutes at 275' for a total of around a 110 minute dive.

    When I left Santa Rosa, my Shearwater displayed my GF99 (Leading Supersaturation) at 29% theoretical maximum with with probably the 5th slowest compartment leading. Upon cresting the hill just past Las Vegas, NM on I-25 it displayed GF99=16% with the 3rd slowest compartment leading. I did not note the surface time at this point. As I was driving through Raton, I watched the GF99 display drop form 1 to 0% with the 2nd slowest compartment leading. This was at about 3:20 surface time. When I crested Raton Pass, the GF99 was still 0% at 3:29 surface time.

    As Raton Pass is higher elevation than Denver this should be the worst case supersaturation for the drive home and based on my Shearwater should have been perfectly safe, even after a deep Trimix dive at Rock Lake.

    That said there is no science showing the body reacts the same on the surface as in the water and everyone has to make their own personal decision on the risk. I personally was breathing Oxygen for about 85% of the drive from Santa Rosa to Raton Pass.

    Edit: Shearwater assumes you are breathing air when not in dive mode. This means the Oxygen I was breathing during my drive was not taken into account for the stated gas loading above.
     
    Last edited: Jul 17, 2018
  4. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
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    This is excellent information! Thanks!

    Just a note for people who have not studied decompression diving--it includes a surprising contrast to recreational diving. In recreational diving, when you surface from a dive and go through a surface interval, all your tissues are off-gassing. That is not true for a serious decompression dive like the one Josh completed that day. On his last two decompression stops, he was breathing pure oxygen for longer than most recreational dives. As a consequence, his fastest tissues had nitrogen saturation lower than ambient pressure. That means his fastest tissues actual on-gassed during the first part of the surface interval. As he noted above, it is the slower tissues that are most at risk and which must be protected.
     
    Last edited: Jul 17, 2018

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