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Wreckage Recovery from 900 feet

Discussion in 'Wreck Exploration and Expeditions' started by Fzaheer, Jul 26, 2014.

  1. Akimbo

    Akimbo Lift to Freedom Volunteer Staff Member ScubaBoard Supporter

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    Fair enough, everything is relative. To commercial diving professionals, a body recovery is a lot safer than the heavy construction-type activities they normally do. The last I heard, the leading injury to commercial divers was lost digits. They get their fingers between the load and target and they are amputated. I don't think you have to worry about sat divers being used for trivial tasks... not with DSVs in the $300-$500K/day range... but it includes a ROV or two!
     
  2. 2cold4california

    2cold4california Nassau Grouper

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    I mean there are tons of salvage options to exhaust at 900fsw before you go to a sat dive on it, right?


    I look at sat dives below 200M as basically rolls of the dice. Diving that deep takes a toll on the body that doesn't just go away. I just think if I were in that situation, and they asked me to retrieve a body at 900fsw, it would have to be Jesus or Stalin or Caesar for me to consider it.


    And on rebreather, which is actually what I think OP prob is thinking of when he says "diving", this is just plain unsafe. I think we can agree that 900fsw outside of a sat or Exo is unsafe?


    You may be right about the sat dive posing acceptable risk to some.
     
  3. KWS

    KWS ScubaBoard Supporter ScubaBoard Supporter

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    After watching a movie or two and spending 20+ years in subs, I can tell you what you ask is a cake walk and in a park no less. The toughest part of the process is location location location. and money

     
  4. tursiops

    tursiops Marine Scientist and Master Instructor ScubaBoard Supporter

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    That's what posts 2-3-4 said.
     
  5. Akimbo

    Akimbo Lift to Freedom Volunteer Staff Member ScubaBoard Supporter

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    A good side-scan and ROV survey of the site would always be the first step. The ROV/diver decision can be pretty clear-cut after that. A ROV can easily handle simple remains recovery in something soft like a aircraft... which is probably in little bits of rubble sinking in the mud and strewn over miles.

    However, let's say the job calls for recovering a historic aircraft that is largely intact. That information wasn't included in the OP. That would be a challenging engineering problem in a lake, let alone in 900'. We aren't in the business to judge if the job needs to be done, only if someone is willing to pay for it.

    That hasn't proven to be true for sat divers. There was a lot of concern over different forms of bone disease in the early 1970s. Only the most experienced divers made it into sat due to their skill doing the work (not as a "reward") :wink:. Customers were paying big bucks and expected the work to be completed quickly. The early studies showed all kinds of bone and joint problems but it turned out to be mostly from the deep mixed gas bounce diving they did before sat. They really didn't look at it before, or have the imaging equipment.

    Like landing an aircraft, decompressing is physiologically the most dangerous part of the dive. Sat divers decompress once for 30 days of work, maybe 4-6 times a year. They also use a very conservative decompression schedule:

    http://www.scubaboard.com/forums/commercial-divers/467739-what-saturation-diving.html

    It is cost-effective not to bend a sat diver because treatment can hold up a fantastically expensive logistics miracle.

    Except for operating in sea state 6 (which they do), I usually feel much safer in sat than on Scuba. You have a large team of highly trained (and paid) professionals looking after you. You have backup gas and analyzers out the wazoo. You are always in voice communications (albeit it squeaky but unscrambled), have a TV camera mounted to your hat, and often a ROV watching you and helping to light the work site. You also have a standby diver ready to drop out the trunk of the bell at the other end of your umbilical and these days often have another sat diver with you. I understand most operations have started putting locator pingers on the divers in case the umbilical gets severed.

    Come to think of it, outside of the work being performed even surface supplied diving is far safer than Scuba.

    I didn't get that impression but you could be right. I would agree that diver intervention other than sat at that depth would not only be extremely dangerous, but unproductive. I doubt that you will find a more ardent critic of many "technical diving" activities on Scubaboard than me.

    No diving is safe, nor is driving to the boat or walking to the grocery store. :wink:

    Some people have made 500' plus bounce dives on open circuit and rebreather SCUBA systems. The question is what did they accomplish besides grabbing a tag off a line? Weigh that against the probability of living the rest of their life looking at ceiling tiles with tubes in all of their orifices. We all make choices.
     
    Last edited: Jul 28, 2014
    Wingy likes this.
  6. iain/hsm

    iain/hsm Manta Ray

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    2cold4

    With respect I would both disagree and further question this, Let me explain why. Firstly my background as a commercial offshore diver and honestly I have never heard of a multiple fatality in GOM involving a SAT chamber fire/explosion, not on my 35 year watch at least. That of course does not preclude that a multiple fatality may have happened and if so I would genuinely like to have more facts about this incident.

    But it doesn't add up thats all.

    Second there is always a chance that rumour and fable get in the way of truth. So much so that eventually some may even believe a lie. Especially with the press bending things out of shape to make more of a story.

    This is one of the reasons you will notice why I always give clear, precise and verifiable background data to my diving posts simply in order for those with interest to verify factual truth.

    So to this question of multiple diver deaths in a chamber explosion/fire. In order for a chamber fire to result in explosion you need oxygen and lots of it, together with the fuel and ignition source.
    In a percentage term you need greater than about 30% Not forgetting the partial pressure aspects of saturation diving even during shallow decompression the chamber atmosphere is never allowed into this threshold for an oxygen related fire/explosion to occur.

    That however doesn't preclude a fire, wire short electrical etc and in that fatality can and has occurred but by smoke inhalation not as you have described a flash oxygen fire/explosion.

    Conversely even with small 54 inch DDC (deck decompression chambers) used universally for Sur D O2 in air diving. The blow down using air would never go below 40FSW so again the percentage and PP02 is insufficient for an oxygen PP related explosion. Unless by means of say the BIBS mask oxygen leakage but again this has to be a major leak and a gross breach of normal working procedure standards, with using oxygen BIBS (built in breathing system) with overboard dump systems of the exhaled gas and continuous chamber oxygen percentage monitoring by gas analysis being standard procedure.

    Further more in all my experience with SUR D 02 only one diver is normally in the chamber at a time therefore negating this "multiple death" aspect of your quote.

    Incidently an air chamber at 165FSW (50MSW) would be approaching the PP threshold but the application for having an air chamber at 165FSW would only be a serious type 1 bend or omitted decompression and again no multiple divers would be involved save the diver (now patient) himself and medic/attendant. Also I suspect in such serious condition "electronics" would not be brought in for entertainment say.

    Further most Type 1 modern recompression procedures, allow the use a 50/50 mix of 02/Helium, heliox and use a Comex 30 treatment table. This reduces the chamber depth from 165 FSW (50MSW) to 100FSW (30MSW) and the 50% oxygen mix with 50% helium reduces drastically the TTUP total time under pressure. (reference below)

    I have only been involved in one omitted decompression incident requiring an air chamber DDC to 165FSW and using air only when working for Maritime Offshore Projects 1981 MV Suffolk Blazer on the West Sole platform pipeline and in that the only "explosion" we had was by intent after finding an old 500lb WW2 mine beside the 16" gas pipeline. (needless to say the mine was moved prior to its detonation and by caution the pipeline flooded)

    But you see my point, against clear decisive verifiable fact it all gets out of shape doesn't make sense and why I suspect your story is a cut and paste article you read about in the papers at best and downright lies at worse.

    Out of interest my other reason for asking details regarding this offshore oxygen chamber explosion is that by coincidence I am also a co author of the publication:


    "Guide to fire safety standards for hyperbaric treatment centres. British Hyperbaric Association Technical Working Party Report. Aberdeen: British Hyperbaric Association, 1996."


    Fire-safety standards for hyperbaric oxygen facilities : The Lancet


    Any specific detail you have of this fatality I would be very grateful to receive further details. Iain Middlebrook


    Comparison between USN6 and Cx30 recompression schedules for DCI
     
    Pullmyfinger likes this.
  7. 2cold4california

    2cold4california Nassau Grouper

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    It is possible by "everyone" he meant one or two guys. It was told to me by a captain of a dive boat off looe key in 2010. The story was the guy brought his cell phone in to text his very young (i think 6 year old) daughter. He apparently hid it on purpose and when he turned it on the oxygen and helium caused either a fire or explosive decompression of the chamber. Either one would doubtlessly kill the man. Again, its anecdotal, but the story was good and I think there is some truth to it.

    I will read the articles, thank you for posting them. I think the story is based on something that happened. It was repeated by several others and was a very sad story. You are correct that this stuff gets overblown and safety in general is pretty decent with almost any job controlled by OSHA (aka in the US). Its all relative. I would never consider being a cop because I think that's too dangerous, but a lot of people would.


    There are diving practices that I do think are dangerous. In the context of the OP's post, 900fsw body retrieval should be done by ROVs whenever possible. Could OP clarify if he was referring to rebreather/Sat/Exo/sub or all of them when he said dive on the plane?
     
  8. boulderjohn

    boulderjohn Technical Instructor ScubaBoard Supporter

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    A ScubaBoard Staff Message...

    This is another reminder to stay on topic with your posts. I know we all tend to go off on tangents in these threads--and I am normally as guilty as anyone. On the other hand, let's avoid tangents that are not in some way directed toward the topic of this thread. Let's especially avoid tangents that are really attacks on other posters without adding anything of value.
     
  9. Akimbo

    Akimbo Lift to Freedom Volunteer Staff Member ScubaBoard Supporter

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    You are correct, not on your watch. The only chamber fire in sat I am aware of was at the Experimental Diving Unit at the Navy Yard in Washington DC on 16 February 1965. This report indicates that all other confirmed chamber fires were in Hypobaric (altitude) and clinical chambers.

    http://c.ymcdn.com/sites/membership.uhms.org/resource/resmgr/gcc_13/sheffielda.pdf

    I recall "rumors" of a multiple fatality chamber fire in the Gulf of Mexico about that time but never heard enough detail to be sure it was true. The story goes that they were running a Sur-D-O2 and the fire caused the chamber to explode killing people outside too. That part was fairly consistent but the company, year, and field changed every time I heard the story. One version even said the diver was smoking while on BIBs. Sounds non-credible today but I wouldn't bet against it at that time in the GOM.

    ---------- Post added July 28th, 2014 at 10:06 AM ----------

    That is definitely a sea story. There have not been any chamber fires during commercial diving operations since the cell phone was invented. I would not be surprised if this whole story evolved from a "what if scenario", inspired by the EDU fire, that got out of hand. Chamber fire was on everyone's mind in the late 60s and early 70s, after which it became much more widely understood. It is amazing how sea stories can take on a life of their own.
     
  10. iain/hsm

    iain/hsm Manta Ray

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    That part is true. It was Acadiana Divers in 1997 SUR D 02 and a standard deck chamber DDC. Jim Little was the diver on BIBS smoking in the chamber causing a fire and his own death. Again to be clear to all, an air diver in a deck decompression chamber at 30FSW. Not saturation and not a multiple fatality.

    Incidentally by comparison and for our friend of the few ADV suit dives in the GOM.

    Jay Shepard was the pilot of a WASP suit in 1999 working for Oceaneering GOM in 972 FSW again around our OP target depth.
    While lifting him/it out of the water the lifting gear gave way on recovering the suit in the 100 foot gap between the surface and the rig deck.

    The shock load swung the suit up under the semi sub platform and broke off one of the arms against a deck plate.
    The suit fell back into the sea minus its articulated arm and sank to the pontoon.

    Subsequent investigation found that the single shackle used to attach the shackle "pin" to the WASP Suit to the lifting frame was not rated for the lift weight load of the WASP suit in air. Jay Shepard was the single fatality. Iain Middlebrook
     

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