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Thread: Deep Stops

  1. #141
    TDF Member Clare's Avatar
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    I personally always used to wear a dive timer that alarmed at 10 mpm and used to accelerate until it went off

    EDIT - For the avoidance of doubt - I still do. I am just out of UK deep diving at the moment as I have been on extended maternity leave Working back to it now though.

  2. #142
    Old but keen Mark Chase's Avatar
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    Just to pick up on one comment.

    Ratio deco is nothing like 20/85 or any other GF for that matter.
    ratio deco has no set safety margin.

    If you do the math for 20 dives at 20 depths with 20 different durations and then map the results against GFs till you get a similar profile, you will find your running 20/80 to 10/125 and most GFs in between


    That was the fundamental problem with Ratio deco. It wasn't a deco system. It was a mathematical progression used to mimic a deco system.

    You needed to run ratio deco along side GF or VPMB and learn its idiosyncrasies and adapt your RD to suit

    I ran RD (my version) against Shearwater GF 30/90 for several years over several hundred dives and as a result I could dive a single deco computer with RD back up and fulley understood where RD needed tweeking to make it work close to my preferred GF

    To the best of my knowledge, real time experience and comparison with tables & tweaking was the way RD was taught


    I would be 100% confident using RD to mimic 30/90 on a dive of 3 hour duration to 60,70,80M on a CCR with a 1.3 set point.

    Out side those parameters I couldn't do it with any degree of certainty


    As said before, now I run deco without deep stops I have abandoned RD altogether and now use two dive computers (Shearwater) and a depth and bottom timer (Sunnto).

    I think its a bit sad they have abandoned RD.

    I am sure with some effort it could be adapted to modern deco theory

    Mind you I did think once they went CCR & chose the JJ they would be silly to ignore that extremely competent GF deco computer on their wrists.


    Its perfectly understandable that GUE were anti computer in the 90s and early 00s as the tec didn't exist. But over decade later we now have excellent decompression computers which are both flexible and reliable.

  3. #143
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    I know this is a fairly dead thread but CCR Explorers has 2 threads running at the moment that expand/counter some if the thinking on some of this thread.

    Most notably that a GF profile with a low initial GF isnt the same as a so called deep stop profile like VPM because the distribution of stops and surface supersaturation is different, in favour of the GF profile.

  4. #144
    rEvo-lution iamyourgasman's Avatar
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    Quote Originally Posted by JonG View Post
    I know this is a fairly dead thread but CCR Explorers has 2 threads running at the moment that expand/counter some if the thinking on some of this thread.

    Most notably that a GF profile with a low initial GF isnt the same as a so called deep stop profile like VPM because the distribution of stops and surface supersaturation is different, in favour of the GF profile.
    Iíd be interested to know the expertise of the group discussing it. There are a couple of reasons I havenít looked at CCR Explorers for a long while...the gurus residing there is one of them. Iím probably wrong as it is Simon Mitchell and similar calibers who are in the discussion 😜😂

  5. #145
    Established TDF Member Paulo's Avatar
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    Quote Originally Posted by iamyourgasman View Post
    I’d be interested to know the expertise of the group discussing it. There are a couple of reasons I haven’t looked at CCR Explorers for a long while...the gurus residing there is one of them. I’m probably wrong as it is Simon Mitchell and similar calibers who are in the discussion ����
    Simon Mitchell & Ross Hemmingway have been going toe to toe on CCRX about it.

    Only 1 of them comes out of it having retained dignity imho
    Rememeber anything you read on the internet was probably written by some guy sitting at home in his underpants! Including this !!

    Illegitimi non carborundum

  6. #146
    Established TDF Member nigel hewitt's Avatar
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    Quote Originally Posted by Paulo View Post
    Simon Mitchell & Ross Hemmingway have been going toe to toe on CCRX about it.
    I read as much as I can on the subject but CCRX is maybe a step too far.

    There's a lot of new good stuff come out over the last few years but when the dust finally settles and the science is in my money is on Simon.

    Actually it effects me less and less. As I run towards the end of my diving career (?) I get less and less adventurous.
    Helium, because I'm worth it.
    Waterboarding at Guantanamo Bay sounded like a radical holiday opportunity until I looked it up.

  7. #147
    Dive tart, and 'tog Pete Bullen's Avatar
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    a friend of mine wrote the following paper on the subject which is well worth a read especially if you like statistics http://www.josephcaruana.co.uk/divin...to-deep-stops/
    Diving, and photography holidays in Gozo
    Private guiding, don't follow the crowd.
    http://oceanfoto.co.uk/

  8. #148
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    As an air/Nitrox OC diver who doesn't go below 50m I have the following rules in place which is a simple as I could make it:
    1. Plan the dive on computer first, deep stops turned off (for which the manual has been read and all signals known - Mine is a Suunto )
    2. Also plan the dive on paper (Slate/wetnote) for the eventualities (Plan, Slightly longer, Slightly deeper, Worst case)
    3. 9m/min until 50% max depth (fast counting should line up with every 0.1m decrease in depth)
    4. Switch to deco gas here if applicable but don't hang around (Deco mix calculated for 1.4ppo2 at 50% max depth)
    5. If my computer tells me to do something else (like stop/slow etc) then I do it, but I think about why and if it's incorrect/faulty and needs to be ignored.
    6. 6m/min (normal counting matching every 0.1m decrease in depth) to 9m then dead slow <3m/min
    7. Complete stops at 6m and take as much extra time as your buddy will endure, or until you start running low on deco gas/air (or getting close to half full if using it for another dive) I often entertain my buddies by performing 'horizontal star jumps' etc. to keep the blood pumping and warm up.
    8. Stop for 30 seconds to a minute every m from 6m to the surface (or however slow your buddy will endure)


    If you have the gas and don't like hospitals or unscheduled helicopter rides you may as well breathe it between 10m and the surface. This looks (quite accidentally) pretty similar to the GUE method Badger mentioned (with some Padding ), but was just something I decided after a long post lecture chat with Neal Pollock, and it works for me.
    I've annoyed a few buddies but I'm quite happy in the water and I'm really good at rock-paper-scissors.
    Last edited by ManualOverride; 17-08-2018 at 03:10 PM.

  9. #149
    Last of the Mohicans gobfish1's Avatar
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    and the shite go,s on .











    ps
    Mr Pollock,s
    seem to over play his hand way to much , some of his stress levels numbers hes pumping out are way way over the top ,
    Last edited by gobfish1; 17-08-2018 at 09:07 PM.
    None diver as of 2018.

  10. #150
    Old but keen Mark Chase's Avatar
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    Efficient deco is the holy grail of decompression diveing.

    The goal is minimum time in the water with no more than moderate risk of DCI (no such thing as no risk)


    Depth is the scary thing to new divers. Each 10m progression is a new level of bum clenching. I remember it well

    But when the novelty of depth wears off, the truly scary thing is decompression commitment.

    It doesent matter if you racked up the deco at 40m or at 140m, looking at your computer and seeing it say 3 hours till you can surface is the scary bit that never got old for me.


    OC was in may ways worse. On CCR doing 6 hours is not a problem but on OC 6 hours is surely 6 X 12ltrs minimum.


    When our dive planning on twin 15s and two 10s for deco you start to look towards efficient deco.

    When GUE came out with Ratio Deco and VPMB2 became the new standard, we all got excited about getting out of the water quicker than ever before. When all we were reely doing was significantly more aggressive deco.

    Doing away with the deep stops all together and running 80/80 or 70/70 gives the same in water times as profiles I used to run like 20/95 but I cant see any other reasoning than 80GF being less aggressive than 95GF

    Its also much more gas efficient for OC or OC bailout on CCR.


 
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