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Thread: I'm only doing this cos they told me

  1. #21
    RBW Member JClynes has a spectacular aura about JClynes has a spectacular aura about JClynes has a spectacular aura about JClynes has a spectacular aura about JClynes has a spectacular aura about JClynes's Avatar
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    Re: I'm only doing this cos they told me

    Quote Originally Posted by nigelh  View Original Post
    I wrote this up with my BSAC hat on....

    The point is that a rebreather dive uses so little gas and costs so little I can keep the thing gassed up with 'mix and judge a short notice dive invitation on the weather not on what gas I might have to throw away and reblend.
    Interesting about your view on narcosis. I've never really felt it but I've never been under major stress beyond 25m. I do know I'm a bit slower mentally at depth - one of the reasons I want to drill more so that I don't need to think in order to fix multiple issues (cos they only comes in threes or multiples thereof). Plus I haven't dived very deep

    BTW: I tend to distrust gear and trust myself. Always nervous of trusting gear. I know diving requires it but the Inspiration stories I've read about do make me even more inclined to distrust kit, especially one with software programs.

    And at this point I don't intend to dive very deep. My motivations are lack of bubbles and staying down longer. And redundancy. I love the notion of a bailout that isn't another human being. 20 metres from me.

    totally random comment, but I've recently bumped into a client (work, not a diving client) that is diving 70-80m wrecks in Malta on air. This seems like insanity to me but not having this depth experience it's a bit rich of me to comment negatively - he has thousands of dives over 30 years so he obviously knows somethings; however I did think that his chances of hyperoxia must my right on the border. V off topic. Brain fart if you will.

    John
    Last edited by JClynes; 11th August 2008 at 22:22.

  2. #22
    RBW Member Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy has much to be proud of Dutchy's Avatar
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    Re: I'm only doing this cos they told me

    For shallow dives and distrust of equipment a Sport Kiss may be the way to go. It's very simple to use and maintain.
    The poorer WOB (The issue that comes to mind when comparing to more modern rebreathers) is IMHO no problem when shallow and improves with the use of He. I'd definately give it a try (even if only in the pool) to help you determine wether to go RB or not. As for sharks I've seen more sharks while swimming than OC and many share my experience....

  3. #23
    Nicholas Smith Abbo has a reputation beyond repute Abbo has a reputation beyond repute Abbo has a reputation beyond repute Abbo has a reputation beyond repute Abbo has a reputation beyond repute Abbo has a reputation beyond repute Abbo has a reputation beyond repute Abbo has a reputation beyond repute Abbo has a reputation beyond repute Abbo has a reputation beyond repute Abbo has a reputation beyond repute Abbo's Avatar
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    Re: I'm only doing this cos they told me

    Hyperoxia and deep air
    On the dive you mention, to 70-80m on air, the PO2 would be 1.7-1.9. On OC I used to limit my PO2 to 1.4; on CC I hold it to 1.2. It's about like asking how safe is it to stand in the middle of the road really: theoretically you would be safer doing that on a country lane than on a 6-lane motorway, but you could be unlucky enough to wander onto a country lane and get knocked over immediately. The day to day variation is reportedly huge in your body's sensitivity to high PO2s. It makes sense to put a large margin for error in your calculations because death is forever. A member of this forum tells on his website of a dive to 150m on air. There are many things I respect him hugely for, but that is none of them: not criticising, but I have to admit I don't get it.

    Is rebreather diving technical?
    Diving isn't rocket science. We learn a load of science in these courses, and I find it fascinating, because that's the kind of nerd I am. Far too much emphasis is placed on the science, and not nearly enough on the practical parts of a course. Rote memorisation is easy to test, but it is not what brings you home alive: diving skills are. I would be very happy with a course that handed me a book and said "read this in your own time and ask me if you have any questions", then spend the whole alloted time really polishing skills. Don't be intimidated by the "technical" appelation: any half-decent teacher would be able to get you through the academic course requirements, even if you were a duffer, which you clearly aren't.

    Is it dangerous?
    It appears to be more dangerous, but this isn't well understood yet. The key, in my opinion, is to have a healthy fear, coupled with the humility to spot your mistakes, admit to them and learn from them.

    Welcome aboard. Interesting set of questions.
    Stay safe,
    Nicholas

  4. #24
    RBW Member JClynes has a spectacular aura about JClynes has a spectacular aura about JClynes has a spectacular aura about JClynes has a spectacular aura about JClynes has a spectacular aura about JClynes's Avatar
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    Re: I'm only doing this cos they told me

    Thanks for the posts. I had an interesting chat (read heated discussion) with my buddy who wouldn't concede that rebreathers have more risk associated with them. He believes they're safer. I eventually got him to concede that they are only safer when:
    1. They don't fail without warning (some eCCR accidents could appear to have this characteristic)
    2. When humans don't screw up:
    a) during flight check (assuming they have one)
    b) underwater

    Which to me are big assumptions.

    That said, I'm going to see if I can try out an mCCR and see how I find it. I'm going to practise basic skills some more first in pool and in open water. I do now firmly believe (as someone with no qualifications to make any statements on the subject whatsoever ) that starting with an mCCR is the best option. Once I'm totally happy with managing the system myself then I'll look at letting some dodgy software developer branch always or interrupt for spurious reasons causing my immediate death.

    I'll repost once I've made the leap. Nigelh, if you don't mind, I might tap you up for a pint to discuss the leap in the next short while. I life at seven dials so not too far to Kemptown. My shout naturally .

    Thanks to all who have been very informative, considerate and most of all, tolerant of someone who knows jack on this topic!

    Cheers,
    John

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