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Thread: Floods and Bailout on Deep Cave Dives

  1. #61
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    HAMMERHEAD!

    Re: Floods and Bailout on Deep Cave Dives

    Quote Originally Posted by Drmike  View Original Post
    it did yes I agree its not a substitute - but it is a very important tool, and there are cases where OC bail doesnt work (lost gas etc) In those instances a diver needs to be conversant enough to switch back and run scr if thats at all possible, which it usually is in all cases other than a full flood. The trouble with never using a tool (in practice) is that when the sh1t hits the fan you dont remember it exists and so dont evail yourself of it. The difference can be life and death

    I've used SCR to keep myself alive on a rig. When I started diving CCR's, the consensus (of, like the 6 dudes who actually dived rebreathers) was reliance on the rig entirely. I still added a bailout tank, and a OC/CC DSV from Tracy Robinette, but SCR served me well.

    In my humble opinion, it is a skill that everyone should practice from time to time - just to stay sharp.


    Kevin.

  2. #62
    RBW Member Nick Tousssaint is an unknown quantity at this point Nick Tousssaint's Avatar
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    Re: Floods and Bailout on Deep Cave Dives

    Hi Dragan

    Obviously after Backgas bailout is exceed stages are added and use as fast as posible first if possible. BM bailout is definetely a consideration to have.

    A triple stage bail out rig is not as comfy as a 125's backmount, also I can breath both tanks gas if reg fails, also is immediately available direct on BOV.
    A bit further 125's plus 3 stages is equal at how many stages 6 ? takes long time to set up and weather may not play.
    I've done 9 stages dives that required a couple weeks of set up dives, and a couple weeks to clea ! However with CCR this can be done in a dive and take the window.

    The discussion is about deep cave diving bailout, not an all around unique rig.
    But backmounted Bailout fits most need with smaller tanks.
    Infact I use smaller backmounted rigs 12's in Europe an al80's in Mx for shallow cave or wreck dives, for other practical needs double 8.5lts, as wide as al4's but taller, fits me fine for anything I will do on al80's or rockbottom of 100bar in 104's,may use two stages but then move to larger back gas

    Here is a pic of 125's an al40 O2 bottle, enjoy !



    Quote Originally Posted by Dragan  View Original Post
    To start with:
    Thanks to OP for sharing the story...

    On to continuing the discussion about backmounted vs. sidemounted/slung BO:
    Cave diving is about the only type of deep CCR diving where I don't really see the benefit of backmounting bailout.

    I can certainly see the benefit in open water applications, e.g. deep wreck diving, where dragging a s**t-load of stages for both bottom and deco OCB during the entire dive seem rather impractical as the depth increases.

    On the other hand, access to bailout gas during cave diving is mereley a setup problem and the only limiting factor is how many setup dives / divers are needed. At any certain part of the cave dive, you only carry what is actually needed at that specific point. Obviously stages need to be placed where they don't impact the environment, but that's a different problem since they are placed during "relaxed" circumstances.

    Even with backmounted, manifolded bailout the amount of time supplied by a given amount of gas largely depend on the actual depth and I really don't see a situation where a backmounted bailout is a far superior method than using the corresponding 2-3 sidemounted stages. Especially since backmounting the bailout usually mean that you need to carry sideslung oxygen and diluent instead. By far smaller tanks than bailout, but still:
    What happens when you need more bailout than what is carried on your back? By then, the dil&O2 stages will be accompanied by BO stages as well.

    If you're talking twin-20liters or similar, that's a large pile of gas to be carried around for the 95% of the dives not needing that amount of bailout. Also, it kind of sucks to either drain perfectly good Tx10/70 just to get EAN32 for the simpler dives. The only thing that sucks more is carrying around 2x20 with Tx10/70 for a 30ish meter dive and still having to carry sideslung EAN32 to be able to get out of the water in reasonable time :)

    /Jonas
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  3. #63
    Sorta New Member w ripley is a name known to all w ripley is a name known to all w ripley is a name known to all w ripley is a name known to all w ripley is a name known to all w ripley is a name known to all w ripley is a name known to all w ripley is a name known to all w ripley is a name known to all w ripley is a name known to all w ripley is a name known to all w ripley's Avatar
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    JM Hammerhead

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    Re: Floods and Bailout on Deep Cave Dives

    Nick

    Nice picture. Do you have one that shows how your BM tanks are configured with their manifold?

    Some of us can't reach tank valves when mounted up like yours, and couldn't reach an isolation valve betweeen the two. Also, hard manifolds (your's appear to be that way from the photo) often require a permanently connected set of tanks (i.e., set of doubles) for each set of BM tanks.

    FWIW, I went a different route having each Dil tank feeding its own LP manifold from its 1st stage. That's the way the HH (and Meg, and others) comes, with one LP manifold for Dil and another for O2 (which is now fed from my other Dil tank). This does allow changing BM Dil tanks without changing their manifolds. The two LP manifolds are tied together with hoses that connect to a slider valve (manifold valve) and off-baord QD.

    If there isn't a "plumbing" problem onboard then you would want to connect both Dil tanks, together or independently, to the BOV for SCR or OC BO (independently because both tanks don't necessarily have to have the same mix in them). It there is a plumbing problem then each manifold can be isolated, and each feeds an independent manual-add valve in its respective CL (one was added to my exhale CL), allowing SCR to continue if one side is down. There is also a 2nd stage on the wing inflator hose that allows OC bailout if the plumbing failure is on the BOV side.

    The "manifold" hoses go over my right shoulder and route under the CL. The OB QD and slider sit at the bottom (and under) the right CL. That way they are out of sight, don't get caught on anything, and are easy to reach with my right hand.

    Her's a picture of the slider and QD. You often see similar setups for O2 cutoffs (DiveRite) and OBs by many.
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    Bill Ripley

    Rebreathers are something that we have to go to in order to dive the way we want to dive. They are not something we go to for any other reason.

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