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PADI Nitrox and CNS Clock

Discussion in 'Advanced Scuba Discussions' started by johnnyblackau, Aug 23, 2013.

  1. johnnyblackau

    johnnyblackau Nassau Grouper

    # of Dives:
    Location: Brisbane
    93
    5
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    Next year i'm considering doing the adv. nitrox course with my LDS. At themoment I have my padi nitrox cert (which i was quite dissapointed in). It failed to touch on CNS clock and how to calculate your oxygen exposure. It really showed a reliance on leaving that up to the computer. It did however show how to calculate MOD, best mix, etc. With the plan to eventually undertake further tec courses, i once read that rec divers will use table and tec divers will use a calculator, i have really cemented that in my planning by working out these by myself rather than tables.

    So my head will be in the right spot prior to doing the course has anyone got some advice on how to calculate CNS clock, exposure and what are OTU and can someone explain how they fit in?

    Thanks in advance!

    Blackie
     
  2. grassgreen

    grassgreen IDC Staff Instructor

    # of Dives: 5,000 - ∞
    Location: mexico
    68
    7
    8
    Interesting post, The course still contains all of what you said that you were missing, but its optional, your instructor taught you the bare minimum, and it left you with gaps in your knowledges, that will need to be filled at a later date if you go into Tec diving, I would recommend to all students thinking of taking the Padi Enriched Air course to tell their instructors they want the "Tables" version. Any decent Instructor will agree to this AND show you how to set your computer aswell..Otherwise what possible reason could they give for not teaching it???
     
    wve and Ste Wart like this.
  3. dvankirk

    dvankirk Barracuda

    # of Dives: 200 - 499
    Location: Cary, North Carolina, USA
    218
    69
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    Tec divers still use tables. They are just specific tables calculated by a computer program. It takes a lot of diving for recreational divers to go over their CNS clock or OTU's, but it is certainly useful to know how to calculate.
     
  4. Jim Lapenta

    Jim Lapenta Dive Shop

    # of Dives: 500 - 999
    Location: Canonsburg, Pa
    16,061
    7,505
    113
    They may not know how to do it themselves?
     
    tracydr likes this.
  5. grassgreen

    grassgreen IDC Staff Instructor

    # of Dives: 5,000 - ∞
    Location: mexico
    68
    7
    8
    Exactly!!! and / or too lazy!!!
     
  6. rjack321

    rjack321 Captain

    # of Dives:
    Location: Port Orchard, WA
    6,319
    738
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    Bad instruction? OTUs and the CNS clock were definitely part of my PADI nitrox course.

    Hopefully you are using a different instructor for Adv. Nitrox/Decompression Proc.
     
  7. Nirvana

    Nirvana Solo Diver

    # of Dives: 200 - 499
    Location: Rio de Janeiro, Brazil
    195
    70
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    You can find a very nice article on tracking CNS oxygen exposure here. The author of the blog is a highly qualified technical instructor, and his book "The Six Skills and Other Discussions - creative solutions for technical divers" might interest you. As a side note, he can be found on this board by the name of Doppler.

    There is also a DAN article here.

    Neither article deals with whole body or pulmonary oxygen toxicity (tracked by OTUs), probably due to the fact that very rarely a sports diver (rec or tech) will suffer from it without first having suffered from CNS intoxication.
     
  8. johnnyblackau

    johnnyblackau Nassau Grouper

    # of Dives:
    Location: Brisbane
    93
    5
    0
    I am... But as we all know the courses themselves aren't long in duration so I'd like to have the grounding before I go in.. So is anyone game to try ad explain it to me? How to calculate cns % for dives and how to track it over multiple dives also can someone explain otu and how they are worked out and tracked ?
     
  9. grassgreen

    grassgreen IDC Staff Instructor

    # of Dives: 5,000 - ∞
    Location: mexico
    68
    7
    8
    you will need a copy of the tables to look at, best thing to do is get the tables then ask the instructor to explain them to you.
     
  10. tracydr

    tracydr Divemaster

    # of Dives: 500 - 999
    Location: North Carolina, 3 miles from South Carolina
    2,683
    728
    113
    Mine,too.
     

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