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Shutdown - Which post to go for first.

Discussion in 'Technical Diving' started by Gareth Burrows, Apr 19, 2012.

  1. johnkendall

    johnkendall Member

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    Fair enough. Don't get me wrong, I'm never going to give someone a hard time for cutting short a dive because of a problem. I just think that if you can fix something, then you should do, and at that point you could consider continuing the dive. Even if you turn the dive at that point it is better to have stuff fixed for the exit, than not to have tried to fix it.
     
  2. big si

    big si Well-Known Member

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    Now we seem to be singing from the same song sheet;)
     
  3. big si

    big si Well-Known Member

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    Well you make your own choices, my choice would be iv lost 10bar my dive plan has changed so im thumbing the dive. However your right in what you say if it was me on a no deco dive then its not to much of a problem but then compare that to a 70m dive 10bar is a consideable amount of gas to lose at that depth and the fact that a unplanned event has taken place which would raise the risk of probability of it happening again. The dive plan would change so the only safe option for me would be end the dive.
     
  4. johnkendall

    johnkendall Member

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    Although at 70m 10 bar lost is approx 2 mins of bottom time. So in that case you could just do 2 mins less bottom time. Again, it depends on what kind of failure it is, and how well it's handled, and how stressful the situation is. I think the worst failure I've had was a o-ring extruding at 85m about 1km back in a cave. We sorted the problem, fixed it, looked at the amount of gas we had and continued the dive. It would have been equally valid to sort the problem, fix it and turn the dive.

    Thanks
    John
     
  5. DaveS

    DaveS Play nice. Enjoy UKD

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    As a purely rec diver I've been entertained and provoked into thinking thoughout this whole thread. Even though you all seem to be saying the same thing (within a reasonable tolerance) it's made me consider how important kit configuration is and how to approach a situation. Thinking first and then acting is not always as simple as it sounds when yuore doing tech stuff apparently. That's not to say that I agree that identical config is a must - I dive with Polly and we know each other's kit inside out. If either of us has a problem then we'll not be diving until its resolved generally. I guess that's easy for rec divers who are used to turning up with divers in all sorts of gear and configurations.
    However, I can fully see the benefits at any depth but especially at technical depths.

    I do have 1 question though that this thread has made me ask a few times. I dive on independant twins occasionally. I therefore have no manifold and no isolator to worry about. If I hear/see bubbles I turn off that cylinder because I can identify exactly which has failed (LPG showing sudden drop, 2nd stage spewing gas, bubbles from either shoulder etc.). At what point do indy twins become less risky than manifold twins?

    I must state that I have no technical training and therefore it's an honest question given the debate above.
     
  6. johnkendall

    johnkendall Member

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    Hi Dave,

    One big advantage of an isolator manifold is that if you have a failure of one regulator, you can still get to all the gas through the other one. This enables you to maintain more capacity for your exit than if you lost one system in a set of independants. Indy twins work well if you have no team to help as one failure cannot drain both systems, but for me the advantages and flexibility of the manifold outweight that benefit.

    HTH
    John
     

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