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When does recreational diving become technical diving

Discussion in 'Technical Diving' started by Iain Denham, Jun 2, 2016.

  1. furryman

    furryman hmmmm
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    CMAS has a definition:
    "2.1.65 “Technical diving” shall mean diving, other than sport diving, speciality diving or commercial diving, that takes divers beyond the normal limits of sport diving. It is an activity that includes one or more of the following:
    - diving beyond a depth of 40 meters;
    - any dive that requires a mandatory decompression stop;
    - any dive in an overhead environment with a restricted vertical ascent to the surface beyond the cavern zone
    - any dive during which accelerated stage decompression and/or the use of multiple gas mixtures are used during a single dive"

    That definition would exclude much of what BSAC has traditionally considered as being "normal club diving", from Sports Diver level onwards.
     
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  2. Wibble

    Wibble Fish don't talk
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    I.e the theory part of training, was not meant in the scientific definition. But as written by Garf, it's one-to-one at 45m and add 5 mins for every 3 metres.
     
  3. jb2cool

    jb2cool Moderator
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    when you are taught ratio deco you are also told that it's a crude estimation and essentially it's fitting a line to a curve (ratio deco is a linear rule where as the deco required is more exponential) , it's fits well at one point but if you do shorter dives it's overly conservative and for longer dives it's highly aggressive.

    It's a tool to be added to the toolbox but it's not the one and only tool I'd use.
     
  4. jb2cool

    jb2cool Moderator
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    Ratio deco also has specific gas requirements. It assumes you are diving 21/35 and using 50% as a deco gas, did you take that into account? You can't just use it for any backgas
     
  5. becky9

    becky9 Diving bore!

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    [Shakes head].....So what is the lesson they teach you about deco, when they talk about Ratio Deco wibs? x


    Edit: I don;t even want to expand on it, because it'll be another little 'wibs knows all this shit' and can spout freely when to make it look like he knows what hes talking about, when actually missing the point - i.e. here x
     
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  6. Tel

    Tel Super Moderator
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    FTFY :)

    That definition would include much of what BSAC has traditionally considered as being "normal club diving", from Dive Leader level onwards.
     
  7. becky9

    becky9 Diving bore!

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    You can use other back gases, sometimes it needs some thought, 18/45 is fine others need a little thought x
     
  8. Iain Denham

    Iain Denham Active Member

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    If I am reading the posts right it seems that any dive over 40m would be classed as a "technical dive" as that is beyond most rec divers quals and would start to need mix gases (unsure of that as am not trimix trained)?

    I`m assuming also a weak nitrox mix could be used at say 45m so with a mixed gas (nitrox) and the depth (45m) then this would be what would be classed as a technical dive?
     
  9. Tel

    Tel Super Moderator
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    Not quite, over 40m would fit, but it's mutiple gases which means more than one.
    You could have two Nx mixes one for bottom gas and a stage, doesnt have to be trimix, but not just backgas.

    TBH though it's easy to blow that defintion off just on #2 as a BSAC Sport Diver is deco trained and you could go
    into deco easily at under 40m.
     
  10. Iain Denham

    Iain Denham Active Member

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    Ok so what would be an ideal gas for 45m?

    Or is that a whole new can of worms?
     
  11. Tel

    Tel Super Moderator
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    Nah easy awnser, ideal would be Trimx :)

    At 45m the max you could have on Nx would be 24%, so not that much of an advantage.
    If all you have is air that's all you have, but as you said ideal them it would be mix :)
     
    #31 Tel, Jun 3, 2016
    Last edited: Jun 3, 2016
  12. Doomanic

    Doomanic Dinosaur Wrangler
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    25/25 or 21/35. They deco out about the same, 25/25 is cheaper but you run the risk of exceeding a PPO2 of 1.4 if you stray deeper than 45.
     
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  13. jb2cool

    jb2cool Moderator
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    I'd go along with this too.

    Who cares what some people class as technical and what others class as recreational, is it important? I'm more comfortable at 35m in the Red Sea than I am at 25m in the English channel. The Red Sea dive is technically a more serious dive but on the day it doesn't feel like it. There are some very grey areas between tech and rec and whatever set of rules you come up with there are probably exceptions.
     
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  14. becky9

    becky9 Diving bore!

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    To turn it on its head, almost doing a mark powell ;) what do you think? What criteria do think you should consider? x
     
  15. Doomanic

    Doomanic Dinosaur Wrangler
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    Once you are into trimix, deco and long bottom times you really want a bereaver. Then every dive is technical, even a bimble in a puddle checking out a new wing...
     
  16. jb2cool

    jb2cool Moderator
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    Sounds like a pain in the ass to me.
     
  17. Iain Denham

    Iain Denham Active Member

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    Did wonder when a bereaver would be mentioned ;)
     
  18. Iain Denham

    Iain Denham Active Member

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    As I am only nitrox trained and then not any form of accelerated then for me it would be 24 or 25% weak nitrox as the best I could do (not much advantage over air I know) so for me that would be best. but run time would have to be short even with a twin set?

    EDIT: on V planner 44m for 20 mins would give me 19mins at 6m, 4mins at 9m and 3mins at 12m so not an ideal gas to use but all I am qualified for.
     
  19. Doomanic

    Doomanic Dinosaur Wrangler
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    Yep. That's why I call it "The Faff"... :D
     
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  20. rivers

    rivers Member

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    And this is where ADP comes into play if you wanted to stay the BSAC route. Provided your taught how to cut your own tables using v-planner or something similar and not dive the crazy aggressive profiles the ox-stop tables give you, it's not a bad course. Not sure what conservatism you used, but bung some 50% in a stage and you're looking at roughly half the deco time.
     

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