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  1. 2 likes
    Hi Derek - fascinating (And NO, I did not follow the maths!). Basically used records of over 3,000 actual dives and applied a three state model to predict no DCI, mild DCI (Pain only) and Serious DCI (Cardio/neurological DCI) They used the 2008 (Rev 6) USN tables 'no decompression limit' to compare the US Navy's 'standard' of accepting up to a 2% risk of mild DCI and 0.1 % risk of serious DCI (I'm not sure many commercial diving people will accept a hit rate of 'one serious DCI per 1000 dives as normal) They concluded that the USN 2008 'no decompression limits' was conservative for mild DCI - ie you could - theoretically!!! - dive longer for the before you reach the 2% risk of mild DCS BUT they also noted that you had to 'vastly reduce' bottom times to keep within the 0.1 % risk of serious DCS To meet the 0.1% risk of serious DCI, the table they quoted was the French Navy NM90 table. Which kind of supports a lot of people's gut feeling that the old USN air tables are a tadge risky when used straight out of the box - even the US Navy concluded they produced an unacceptably high rate of DCS in the deep air range - That's why they upgraded from Rev 6 to Rev 7 last yea (And why they upped from Rev 5 to Rev 6 in 2008). I believe - but am open to being corrected! - that the French Navy tables are based on a Haldanian model (derived from extrapolating data from actual dives) as opposed to Algorythms (bubble modelling maths) which kind of pushes one to think that science is good, but actual experience is better. It would be interesting if they re-ran the modelling using the NDL limits from USN Rev 7 to see if the new version is any safer. Thanks for posting the link!
  2. 2 likes
    We've been monitoring the progress of this system for a while now and asking lots of questions of the developers - it seems as though it works well in tanin-stained waters, when it comes to water that is dirty with particles it improves visibility in limited viz., but doesn't help when the particles are really thick and you can't see bugger all - even the IR light can't penetrate the particle soup then.
  3. 1 like
    Open Attached Excel sheet IMCA on line Video Links April 2017.xlsx
  4. 1 like
    I will be receiving the Printed Copies for Review on the 17th or 18th this month. Most divers will never have the chance to be taught to burn properly, they will learn in the field as most of us have. Hopeful the way I've put this manual together, they can buy it and learn how not to kill themselves, even when surrounded by a team that knows less than they do. The smart ones will note that my e-mail address is in this course, the smart ones will ask what they don't understand. The attached pictures are ones I created to help make the point about: Why the Drag method: IF YOU'RE IN FRONT OF THE CUT WHEN AN EXPLOSION HAPPENS; Oxy-Arc Burning can be done safely!
  5. 1 like
    I'm going to read it and then comment
  6. 1 like
    Link to new DCI modelling http://www.news-medical.net/news/20170315/Researchers-create-new-model-for-predicting-severity-of-decompression-sickness-in-divers.aspx Scroll to the bottom of the page to download the document as well The link to the journal PLOS ONE article is below. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0172665
  7. 1 like
    John, i don't understand this article. You can't predict where a bubble will end up and how painful it will be. Each dive and diver are different. Hence a neurological exam.
  8. 1 like
    This technology will never prove it, we will see what the divers who use it say
  9. 1 like
    Interesting link to new DCI modelling http://www.news-medical.net/news/20170315/Researchers-create-new-model-for-predicting-severity-of-decompression-sickness-in-divers.aspx Scroll to the bottom of the page to download the document as well The link to the journal PLOS ONE article is below. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0172665
  10. 1 like
    Once it has been developed to the point of being surface monitored, I can see the oil companies requiring this technology for all asset inspections in zero visibility. The sales people ought to be marketing this to Chevron, Shell, Exxon-Mobil, BP, Total, Aramco and the rest of the lot just as soon as they can get the imagery onto a surface monitor. This looks like breakthrough technology to me.