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Accident on Southern Cal Oil Rigs Dive

Discussion in 'Accidents and Incidents' started by Hatul, Nov 11, 2017.

  1. HalcyonDaze

    HalcyonDaze Manta Ray

    # of Dives: 500 - 999
    Location: Miami
    711
    552
    93
    Exactly. At this point, we have a very few known facts and some items that have been reported in posts on this thread which may be true or may be simple hearsay. At this point I'm choosing to go with a null hypothesis of proper dive planning being followed rather than assuming the deceased pushed the limits in one or more ways. Given what has been stated about him in this thread and elsewhere, the former seems more likely than the latter.

    What happens in a lot of these A&I threads, as boulderjohn posted earlier, is the desire to find some clear root cause of the accident:

    A lot of the posts in this thread seem to assume that something had to have gone wrong in order for this event to happen - exhaustion, exceeding MOD, bad dive planning, etc. So if we're going to discuss those, why not lay out what would have had to happen before any of those scenarios came into play? Then we'll at least know what information is needed to support a particular hypothesis rather than blindly speculating - for example, whether or not the deceased had done both prior dives or whether there was heavy current that day.
     
  2. Hatul

    Hatul Solo Diver

    # of Dives: 500 - 999
    Location: Tustin, California, United States
    3,954
    536
    113
    I just want to add a generic dive safety comment, since we don’t know what Henry had in his tank. Personally I don’t use Nitrox on dives that have no bottom such as this blue water dive or wall dives.

    On a deep dive at Punta Sur in Cozumel (but still less than the MOD of EAN32) I noticed the dive guide also used air, and when I asked him about it he said It’s in case he may need to chase after someone deep and exceed the MOD.

    I also recall reading a case report of a diver having a seizure on Nitrox at around 1.4 atm O2 partial pressure. In Cozumel I use air for the first deep dive and EAN36 for the second shallow dive.
     
  3. Kevrumbo

    Kevrumbo Solo Diver

    # of Dives: 1,000 - 2,499
    Location: South Santa Monica Bay/Los Angeles California, USA
    5,616
    1,317
    113
    Again and yet again, based on what scant published and third party information there is, the best non-trivial hypothesis is the one that has the fewest assumptions. A "null hypothesis" is obviously a trivial reductio ad absurdum statement and does nothing to help make sense of this accident, along with useless admonitions on speculation.

    Again. . .There is a common experience for all SoCal oil rig divers of a live boat drop-off and surface fin-kick swim to get inside the structure's boundary, in that you have physical activity with a natural physiological tachypneic (increased breathing rate) response even before the descent to depth. Potential compounding issues are the victim's fitness level and any underlying relevant medical history -and therein lies your root "factors", @HalcyonDaze and @boulderjohn, factors that are presently unknown at this time as well. Therefore Rule Out CO2 Toxicity/Hypercapnia in Scuba Diving activity as the precipitating event to the primary Cause of Death by Drowning. . . (This differential diagnosis of Hypercapnia is supported by the research referenced in post #133 and the video in post #139).

    See also this lecture on Respiratory Physiology with regard to Carbon Dioxide starting at the 4:00 minute mark:


    What we as Oil Rig Divers can learn from this, is to take a few minutes to recover and regain a normal relaxed breathing rate -without the work-of-breathing of the regulator in mouth- on the surface, before beginning a descent to depth. If you cannot, and especially if there are equipment problems or water conditions turn out to be too rough for your ability, abort and signal the Diveboat for pick-up.

    On Oil Rig Dives, I always use Air and a DPV/Scooter to provide mobility at all phases of the dive -including the surface swim for both drop-off and pick-up. If going far below the second horizontal crossbeam framework (36m/120') down to the third & fourth tiers for significant minutes of bottom time, I usually breathe an appropriate Helium mix in a twinset together with 50% & 100% O2 deco gases.

    Another Lesson Learned from this Accident: The most important factors to consider when using any recreational Oxygen-Nitrogen gas mixture are gas density/work-of-breathing, ppO2, and narcosis. Physical activity at deeper depth together with increasing gas density eliciting the effects of work-of-breathing and spiraling CO2 retention, adds to the anesthetic effect of Nitogen Narcosis, along with elevated ppO2 levels which in turn increases the chances of Oxygen Toxicity Syndrome.

    The critical gas density point for Air (and for EANx32 & 36) is right at 40m/130' -which just happens to be the maximum recommended recreational depth limit. That the surviving diver reportedly tried to rescue the deceased by going down to a depth of 50m/167' (with whatever remaining tank pressure) is commendable. Amazing and fortunate that other than a CO2 headache, this diver did not go hypercapnic into unconsciousness; Oxtox seizure; or on the ascent, run out of breathing gas and develop acute DCI.
     
    Last edited: Nov 20, 2017
  4. Hatul

    Hatul Solo Diver

    # of Dives: 500 - 999
    Location: Tustin, California, United States
    3,954
    536
    113
    It's now been a few months and the investigation must be complete by now. Anyone have any updates on the cause of this accident?
     
  5. boulderjohn

    boulderjohn Technical Instructor Staff Member

    # of Dives: 1,000 - 2,499
    Location: Boulder, CO
    25,375
    16,478
    113
    I imagine the investigation is complete by now. According to what the sheriff's department told me immediately after the accident, once the investigation is complete, all you have to do is contact them to get it. If someone were to do that and post the information here, I am sure it would be greatly appreciated.
     
  6. Freewillow

    Freewillow Divemaster

    # of Dives: 500 - 999
    Location: Brussels
    1,642
    401
    83
    just buying some :popcorn:and waiting for any official news. My guess is that I will be finished with it before that time :happywave:
     
  7. Dizzi Lizzi

    Dizzi Lizzi Manta Ray

    # of Dives: 50 - 99
    Location: California
    884
    729
    93
    Los Angeles Coroner website states "DEFERRED Pending Additional Investigation"
     
  8. Dan_T

    Dan_T Great White

    # of Dives: 500 - 999
    Location: Texas
    3,717
    1,830
    113
    True for going to the rig, as the rig is anchored to the sea bottom, but not the other way around. The captain asks us to just loop our fingers around the line as a guide & we need to fin ourselves to the boat. If all 20 divers pull themselves to the boat, after finish diving in the rig, the boat will be pulled towards the rig.
     
  9. stretchthepenn

    stretchthepenn Nassau Grouper

    # of Dives: 200 - 499
    Location: Atlanta, GA
    145
    76
    28
    I dived the Eureka, off Long Beach, once. It wasn't fun. It was amazing.
     
  10. KevinNM

    KevinNM DIR Practitioner

    2,638
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    A good rig dive is amazing. Lots of large animals, colorful as heck, little fish everywhere.
     

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