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Last breath - hard hat story

Discussion in 'Scuba Diving TV & Movies' started by Scared Silly, Apr 24, 2019.

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  1. Dan

    Dan ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: Lake Jackson, Texas
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    What is gas composition for typical 100m saturated dive? I just heard from the movie about using helium & oxygen mixture, but didn't hear about the % oxygen nor any nitrogen being used.
     
    Dan, May 18, 2019
    Dan, May 18, 2019
    #21
  2. Dan

    Dan ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: Lake Jackson, Texas
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    Never mind. I found the answer from Gas blending for scuba diving - Wikipedia
    • "He/O2 12/88" would be a heliox blend with 12% oxygen and 88% helium. This gas would be used in commercial diving to depths up to about 100 metres (330 ft), depending on duration, but can not be used shallower than about 7 metres (23 ft) without risk of hypoxia.
     
    Dan, May 18, 2019
    Dan, May 18, 2019
    #22
  3. Jay

    Jay Need to dive more!

    # of Dives: 100 - 199
    Location: Melbourne, OZ.
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    At 6:29 (from the end) Chris L speculates "... high levels of oxygen carried in our emergence breathing gas ..." as for being a possible reason he survived.

    I wonder what that meant, as in how high? 12/88 at that depth is a PPO2 of 1.32. If he was referencing high versus 12% ... I wonder how much higher and what PPO2.
     
    Jay, May 20, 2019
    Jay, May 20, 2019
    #23
  4. Diving Dubai

    Diving Dubai Instructor, Scuba

    # of Dives: 1,000 - 2,499
    Location: Dubai UAE
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    @Akimbo will probably know - he's been there and done that...
     
    Diving Dubai, May 20, 2019
    Diving Dubai, May 20, 2019
    #24
    Jay and chillyinCanada like this.
  5. uwxplorer

    uwxplorer Rebreather Pilot

    # of Dives: 500 - 999
    Location: Los Angeles
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    43
    3 computers died. HP, (or whoever built the triply redundant system) dare to explain?
    Part 2, maybe...
    Great documentary.
     
    uwxplorer, May 21, 2019
    uwxplorer, May 21, 2019
    #25
  7. Akimbo

    Akimbo Just a diver Staff Member ScubaBoard Supporter

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    In my experience, chamber atmosphere is typically +/- 0.3 ATA (PPO2) or 2.74% Oxygen at 100M/228'. The reason they don't shoot for .21 ATA, like on the surface, is there is less margin to the hypoxic limits in case of a gas emergency (pressure loss). Bell and diver breathing mix can go as high as .5-.8 ATA. The bell atmosphere tends to be a little higher because the volume is much smaller than a chamber so can change much faster.

    The bell atmosphere is maintained using the same method as the chamber -- Oxygen is added as required to maintain the target PPO2 while CO2 is chemically absorbed. Virtually all sat dives are done on what is essentially as surface-based eCCR to recirculate the gas so the PPO2 is chosen for the working depth range, usually banked to the closest 1% mix. The diver's hat has a demand exhaust regulator and a hose that carries the gas to the surface where it is scrubbed, metabolized oxygen is added, and compressed into HP banks for reuse.
     
    Akimbo, May 21, 2019
    Akimbo, May 21, 2019
    #26
    couv and Jay like this.
  8. Bigeclipse

    Bigeclipse Barracuda

    # of Dives: 100 - 199
    Location: USA - New York
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    Just finished watching it and wow. Crazy. I recommend people with it. It’s about a real life saturation dive which goes horribly wrong. I don’t want to ruin it for anyone but it’s a good documentary with some real life footage.
     
    Bigeclipse, Jun 6, 2019
    Bigeclipse, Jun 6, 2019
    #27
  9. crcobb

    crcobb Angel Fish

    # of Dives: 200 - 499
    Location: Michigan
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    Watched it with a group of divers over the weekend and everyone enjoyed the movie. Great documentary.

    I also wondered about the highly available system failing, but I've seen enough edge cases cause redundant electronic systems to not fail over properly to not but surprised.
     
    crcobb, Jun 6, 2019
    crcobb, Jun 6, 2019
    #28
  10. MargaritaMike

    MargaritaMike Divemaster ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: On a non-divable lake in SE Texas
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    Dang! I don't have Netflix. It sounds like something I would really like to watch.

    Cheers -
     
    MargaritaMike, Jun 6, 2019
    MargaritaMike, Jun 6, 2019
    #29
  11. Jay

    Jay Need to dive more!

    # of Dives: 100 - 199
    Location: Melbourne, OZ.
    994
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    free trial?
     
    Jay, Jun 8, 2019
    Jay, Jun 8, 2019
    #30
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