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The 'Jascon 4' rescue video - 3 days at 30m and lived!

Discussion in 'Search and Rescue' started by DevonDiver, Nov 27, 2013.

  1. kwinter

    kwinter Rebreather Pilot

    # of Dives: 500 - 999
    Location: South Jersey
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    I thought that might be the case under deeper circumstances. But this was only 30m/100ft. I'm not that surprised that the rescue diver was using heliox, but to put the guy they rescued on it for a very brief ascent into the bell seemed odd.
     
  2. Andyoak

    Andyoak Angel Fish

    # of Dives: 500 - 999
    Location: Perth
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    This article explains some of it
    http://www.nxtbook.com/naylor/ADCS/ADCS0513/index.php#/14

    On my phone so can't type an essay but the article should give you a good idea. Remember you don't have to be deep to need a SAT team, but you do of you want people to spend a long time underwater, such as combing wreckage for bodies.

    ---------- Post added December 7th, 2013 at 11:44 PM ----------

    Addressing your point; surprised they put him on helium to get him out?
    Well being that
    A) you would want him thinking clearly while you got him out
    B) he was going to be on helium for 2 days to get desaturated
    Seems to me the earlier he got on the helium the better.
     
  3. Akimbo

    Akimbo Lift to Freedom Volunteer Staff Member ScubaBoard Supporter

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    According to this article in Subsea World the sat team aboard the Lewek Toucan was at 70 Meters/230' when they got the call. It took 17 hours to transit to the site, which they used to decompress to about 30 Meters/100' (which would normally take more than 25 hours). Naturally they would be on HeO2. I have never seen a bell that could supply different mixes on separate umbilicals, nor can I imagine a reason why you would want to, even in this case. Also, air sats are extraordinarily unusual.

    Virtually all jobs above 50 M/165' are done with surface supplied air and may employ Sur-D-O2 (Surface Decompression using Oxygen) in the deeper range. Saturation operations are fantastically expensive, require larger support vessels, support personnel that outnumber the sat team 3-5x (depending on who gets counted). Everyone on an air diving team except the supervisor cycles between support and diving.

    Open circuit masks are rarely used in saturation diving anymore, except for the standby diver in the bell. I imagine they chose to use a mask for the rescue instead of a hat fitted with surface-based closed-circuit recycling gear for simplicity during the short swim (walk really) back to the bell.

    It would be more expensive to switch from HeO2 to air on decompression since all the Helium from the chambers is reclaimed/recycled these days. Except for Oxygen, gas is rarely added to the chamber after reaching depth. Switching gas would mean ventilating the atmosphere so a lot of the gas being bled off would be heavily contaminated with Nitrogen and Oxygen, making Helium reclamation more difficult.

    You would also have the problem of reducing the PPO2 back down to the 0.3 ATA range in the chambers if you ventilated with air on ascent. Chambers and bells are totally closed circuit with CO2 scrubbers, O2 analyzers, and O2 injection systems unlike typical DCS treatment chambers which are simply ventilated with air.

    Does all this make sense?

    ---------- Post added December 7th, 2013 at 10:31 AM ----------

    Thanks, the ADCI (Association of Diving Contractors International) article is the only interview of divers and supervisors I have seen.

    I can’t tell from the article if they brought an air umbilical from the surface or a mixed gas umbilical from the bell. It sounds like it took them a couple of hours to figure out that they had to bring him back to the bell instead of using Sur-D-O2 on deck. I imagine there is a lot more to the story since any sat super would know that sat decompression was the only practical option.

    I doubt that there was any concern of narcosis, especially after that amount of time. I can see that air would be less likely to freak-out a non-diver on the way back to the bell though.
     
    Last edited: Dec 7, 2013
    Saldiac, CT-Rich, Tigerman and 2 others like this.
  4. TinmanJones

    TinmanJones Angel Fish

    # of Dives: 25 - 49
    Location: Arkansas
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    Where can I find and read these stories?
     
  5. BlueTrin

    BlueTrin DIR Practitioner

    # of Dives: 50 - 99
    Location: London
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    Sorry to resurrect but someone made a cool video

     
    Jared0425 likes this.

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