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Lake Attersee fatality - Austria

Discussion in 'Accidents and Incidents' started by DandyDon, Nov 14, 2020.

  1. KenGordon

    KenGordon Rebreather Pilot

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    Since when is 4 to 10 “about 10”? Read the conclusion. BTW that paper is in part based on the nonsense Deeplife database that Brad here pushes.

    Also, a 150m dive on OC is a very risky endeavour. 10 times that would not be acceptable to anyone. Actual deep or complicated dives are better done CCR and those divers need to understand any issues. “CCR is too dangerous” rants don’t help understanding. I have recently been in some circumstances which would have been deeply unpleasant with an OC time limit, possibly to the point of panic. Having CCR meant it was just a little bit challenging instead.
     
  2. KenGordon

    KenGordon Rebreather Pilot

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    My implication was that if people listened to you (here treating the scrubber as the hard limiting factor) then they might do something else MORE risky as a result. Executive summary: ignore everything Brad Horn says, it is said for reasons nothing to do with the subject at hand.

    Is this diver under stress from the start of the dive? If so carrying on would seem to be a mistake. Really the point of the test is to provide an envelope of performance not to represent any actual dive. That then provides guidance to users about expected worst case performance. How much use that is is for the user to decide.

    As the representative of a manufacturer presumably you could bring real data to the table and tell us how your scrubber compares for a 150m dive vs a 100m one. Or are you just guessing too?
     
    cathal and Mod63 like this.
  3. Dave Kay

    Dave Kay Nassau Grouper

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  4. Dan

    Dan ScubaBoard Supporter ScubaBoard Supporter

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    I carry this CO detector and sniff the tank gas into its sensor.

    A8F383BB-1662-4DFC-BC7B-75A92993292B.jpeg C569C689-F3FD-4BAE-8199-904E30E04EFF.jpeg
     
    BlueTrin likes this.
  5. DandyDon

    DandyDon Old men ought to be explorers ScubaBoard Supporter

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    There are various CO testers. I've tried a few different models, some no longer made. No one likes the extra costs, upkeep, and then the tank testing until you find a bad tank. The cheapest approach is using this unit Inspector https://www.sensorcon.com/collections/best-selling-products/products/portable-carbon-monoxide-detector-meter?variant=4193480964 and gallon ziplock bags.

    There is a sale on this week, using code NOV2020 to get $25 off.
     
  6. Mod63

    Mod63 Dive Con

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    No info on that, and the original post has been withdrawn.
     
  7. Mod63

    Mod63 Dive Con

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    The truth in simple words
     
  8. BlueTrin

    BlueTrin ScubaBoard Supporter ScubaBoard Supporter

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    darren a likes this.
  9. Brad_Horn

    Brad_Horn ScubaBoard Business Sponsor ScubaBoard Business Sponsor

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    Ken, Open Safety doesn’t have a dog in the fight for diving a single scrubber rebreather deeper than 100m and longer than 2hr 45min in 4’C or colder water, to 2.0% SEV measured at the mouth; where the pre dive plan is to remain on the rebreather surface to surface. We simply don’t offer a comparable unit that supports a dive of this nature. Scrubber duration being a known limiting factor. Hence my curiosity around the pre-dive planning conductable in this instance.

    OSELs single scrubber 100m duration both BT and profile with description of testing methodology available at https://www.opensafetyglobal.com/Safety_files/DV_OR_ScrubberEndurance_Retest_SRB_101215.pdf
    Which for your edification shows the significant reduction in scrubber duration from 40m compared to 100m.

    And yes I’m fully informed how well our units perform at deeper than 100m; as they have been tested to 350m. WOB testing demonstrated per link both for single and dual scrubber. But you’ll get the gist of the standard of testing conducted https://www.opensafetyglobal.com/Safety_files/DV_OR_WOB_Respiratory_C1_101111.pdf

    As we know our single scrubber rebreather offers insufficient scrubber duration for >2hr 45min at 100m at 4’C to 2.0%SEV at the mouth. 150m will obviously be considerably less duration than this. And it would almost certainly be utterly exhausted on a 3hr dive, with the only available safety margin a low workload whilst being towed. Breakthrough probably occurring rapidly if you had to suddenly fin hard at depth or during deeper deco.
    Thus necessitating pre-dive selection of a dual scrubber option as part of the documented dive planning process; if you were using one of our systems. Which would offer an element of safety margin still at 150m, due to it’s recommended 5 hour duration; for a dive to 100m in 4’C to 2.0%SEV at the mouth. The excess time buffer enabling known trade off with additional depth in water of this temp over 100m, up to the planned 3hr RT.
     
  10. Turtle78

    Turtle78 Angel Fish

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    According to rumours in the German speaking part of the world, the deceased diver was known to accelerate deco by manually pushing the PO2 way beyond what is acceptable with the MAV. You can't even set the JJ/Shearwater controller to such a high set point. So not an equipment issue, but rather a user issue. But this is hearsay and if not appropriate, MODs can delete at discretion.

    p.s. I am only mentioning this here as a warning not to manually push the PO2 limits to accelerate deco. It would seem obvious, but appears to be quite common practice unfortunately.
     
    BlueTrin likes this.

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