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Thread: CCR Cave Training In Mexico with ProTec

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    RBW Member Hk101gr is on a distinguished road Hk101gr is on a distinguished road Hk101gr's Avatar
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    Re: CCR Cave Training In Mexico with ProTec

    Excellent report Mark. Sounds like an amazing experience...

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    Re: CCR Cave Training In Mexico with ProTec

    Quote Originally Posted by Mark Chase  View Original Post
    However total loss of inboard diluent will mean total loss of wing inflation gas. Not much of a problem open water but in a cave it could be. So the choice now is to run the buoyancy off the dry suit (not my first choice) or to disconnect the dry suit and swap the feed to the wing inflate.
    Why not run your wing from offboard? My BOV and wing run from the manifold with a QD to my offboard. It uses a minimal amount of gas when you get used to balancing it with your suit.

    I calculate bailout on fill pressure -30bar so I've got a lot of padding in there. OK bailout is another thing to monitor but I like my dil just to feed the the loop and that's it.


    With 02 we ran thirds all the time which is both sensible and easy to do. With the average metabolic rate of 1-1.2 a 3ltr will last eight hours +. So only on caves with loads of ups and downs are we going to need to worry about 02. that said a leek can spoil any dive so Id personally have a means of injecting 02 from a redundant supply.
    I don't have a gauge on my O2. Any hint of a problem and it's home time. If there's no problem then the O2 will last longer than I want to be in the water (or my scrubber).

    When open water diving on the Inspo I had my 50% deco mix with a hose on it I could plumb into the counter lung. On my KISS I use a 0.75ltr bottle plumbed into my kiss for manual injection but switched off till I needed it.
    So bailout plus 0.75l bottle plus suit bottle plus onboard plus Rebreather... Wouldn't OC be a hell of a lot simpler? :D :D As I've said before, my two tests are: if OC means less cylinders and/or OC is cheaper then I go OC for cave diving.


    Bailout gas is planned on 100% needed to exit the cave so no thirds. Safety margins were in place via increased SAC calculations and slow and easy progression into the cave.
    That's "roughly" how I plan mine. Only I take an extra of whatever my deepest bottle is. So if I need 1x12 to exit then I take two. If I need two then I take three. I have serious doubts over the survivability of a CO2 hit in a cave. I also tow a scooter if I'm 30m+ with any distance so perhaps I'm just paranoid.

    For turnpoint I go for 1/3 off dil (I don't put a gauge on my O2) unless I've hit a predetermined point (if it's a cave I know) or time (if it's a cave I don't). Even if I've got plenty of dil/bailout/whatever, I turn if I hit that point. I find cave diving CCR a lot more restrictive than OC, if I want to just get in and swim and have a mooch then I far prefer OC.

  3. #33
    So many CCR So little etc Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase's Avatar
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    Re: CCR Cave Training In Mexico with ProTec

    Quote Originally Posted by lizardland  View Original Post
    Why not run your wing from offboard? My BOV and wing run from the manifold with a QD to my offboard. It uses a minimal amount of gas when you get used to balancing it with your suit.

    I calculate bailout on fill pressure -30bar so I've got a lot of padding in there. OK bailout is another thing to monitor but I like my dil just to feed the the loop and that's it.


    I don't have a gauge on my O2. Any hint of a problem and it's home time. If there's no problem then the O2 will last longer than I want to be in the water (or my scrubber).


    So bailout plus 0.75l bottle plus suit bottle plus onboard plus Rebreather... Wouldn't OC be a hell of a lot simpler? :D :D As I've said before, my two tests are: if OC means less cylinders and/or OC is cheaper then I go OC for cave diving.


    That's "roughly" how I plan mine. Only I take an extra of whatever my deepest bottle is. So if I need 1x12 to exit then I take two. If I need two then I take three. I have serious doubts over the survivability of a CO2 hit in a cave. I also tow a scooter if I'm 30m+ with any distance so perhaps I'm just paranoid.

    For turnpoint I go for 1/3 off dil (I don't put a gauge on my O2) unless I've hit a predetermined point (if it's a cave I know) or time (if it's a cave I don't). Even if I've got plenty of dil/bailout/whatever, I turn if I hit that point. I find cave diving CCR a lot more restrictive than OC, if I want to just get in and swim and have a mooch then I far prefer OC.

    All good points but I wouldn't go without a gauge on my 02. Whilst adding the spare 02 and of board suit inflation adds two more tanks I think its fair to say most divers are using off board suit inflation anyway so in fact I am only adding a 0.75ltr 02 bottle which can go on the side of my back plate just like my suit inflation.

    I must stress I wasn't doing this on the course. I am hypothesizing about what Id do on much bigger dives. Seeing as i am a total novice i am receptive to the fact i may be talking crap :D

    I totally agree that on easy dives CCR is harder work in caves than OC. If I could guarantee everything would go to plan id much rather do it on OC.

    ATB

    Mark

  4. #34
    RBW Member Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike's Avatar
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    Re: CCR Cave Training In Mexico with ProTec

    Quote Originally Posted by wedivebc  View Original Post
    But wouldn't you say bailout is based more on distance than time?
    nope not at all - its based on how long it takes to swim out. Diving siphon or spring? (cave) current direction? (sea)

    If for eg. Im diving cave with min-no flow and more or less const depth I know how long my bail gas will last so I turn at/before I reach that time. If theres flow then factor +/- accordingly

  5. #35
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    Re: CCR Cave Training In Mexico with ProTec

    Quote Originally Posted by wedivebc  View Original Post
    I find great enjoyment poking along looking at stuff sometimes taking side excursions but not covering lots of distance. You need to know your bailout range and the penetration distance can be planned before hand so I know how far I can go on my bailout regardless of time.
    of course. but in an overhead you have to assume an exit swim speed to make sure you have enough bail gas for your given exit distance.
    The other factors 1/3 O2, 1/3 dil are time based
    O2 and especially dil is very much cave profile as well as time/metabolism based.
    but bailout gas is basically static until it gets used. Now I have no experience exploring new caves so then all bets are off but for well mapped and planned dives I know my bailout turn point before I start the dive.
    as does any good ccr diver

  6. #36
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    Re: CCR Cave Training In Mexico with ProTec

    Quote Originally Posted by Drmike  View Original Post
    Turn time is governed by when you reach limit of bail gas your carrying* or when you reach 1/3rds of O2 or dil (or whatever gas planning ratio your using) - whichever comes first.

    *before dive you estimate max penetration distance given the bail gas your taking
    Mike

    Thats how I was taught on my course with Bruce Konefe in Thailand. Only asking to understand some other methods and the reasons.

    John

  7. #37
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    Re: CCR Cave Training In Mexico with ProTec

    Quote Originally Posted by Mark Chase  View Original Post
    All good points but I wouldn't go without a gauge on my 02.
    I don't find it relevant to my diving. I've either got waaaaaay more than enough if nothing has gone wrong or far too little if there is a problem. I'm comfortable that a gauge is not giving me a lot of benefit. If there is an O2 problem then I'm going home with no second thoughts.

    Whilst adding the spare 02 and of board suit inflation adds two more tanks I think its fair to say most divers are using off board suit inflation anyway so in fact I am only adding a 0.75ltr 02 bottle which can go on the side of my back plate just like my suit inflation.
    It may well be true that CCR divers will use offboard inflation but if I was doing the dive on OC then I'd more than likely not be unless I had mix backgas. If I can eliminate relying on another cylinder, regardless of size, then I will. I'm not entirely sure what you'd be achieving with the extra O2 bottle. Massive dives maybe but that's not the kind of diving I'd want to be taking my CK on. Adequate bailout is adequate bailout, there's no shame in swimming out on it -- if nothing else the chances of it failing if you've got enough volume are minimal. Extra O2 is one more thing to carry, one more thing to get tangled in the line or keyed into a restriction or shave another m/min off your swim speed. Especially when you've got full OC bailout.

    I totally agree that on easy dives CCR is harder work in caves than OC. If I could guarantee everything would go to plan id much rather do it on OC.
    I've had far more failures in 3yrs of cave diving on a CCR than I've had in 12yrs of OC cave diving, so much so that I've even considered giving up CCR's in caves and going back to OC. I used to think GI3's "ebola" comments were an overeaction to RB's in caves but it didn't take long to actually understand what he meant. Caves magnify problems that you don't notice in open water, that's probably one of the hardest things to get across to wreck divers. Take a rebreather into a cave and you see how much of a bastard a rebreather is. OC isn't, I'm struggling to think of a problem that's happened to me on OC that has been anywhere near as serious as a few that I've had CCR and of the problems I've had OC I'm struggling to see where a RB would have made it better.

    I dive a rebreather in caves for one reason, logistics. If I could get cheap, readily available helium then I wouldn't own one. No way would I be diving one because it's more reliable in an emergency!

    Cheers,

    Stuart

  8. #38
    RBW Member Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike's Avatar
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    Re: CCR Cave Training In Mexico with ProTec

    I think the only reason to have spare O2 is when the dive is a big one and you simply need the O2 vol, or if the deco is so significant that SCR running will give you really extended deco time. A long deco running semiclosed is not much fun

    On normal CCR cave dives I dont take spare O2 - Id run Semiclosed off bail gas if Ive lost O2.

  9. #39
    So many CCR So little etc Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase has a reputation beyond repute Mark Chase's Avatar
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    Re: CCR Cave Training In Mexico with ProTec

    Diving an inspo or similar Id probably agree with you. Diving a MCCR like a KISS the only thing that will really spoil my day is a flood.

    After 5-600 hours on CCR I have suffered a total of 1 unrecoverable flood.

    After 5-600 hours on CCR I have used my bailout in anger once and that was on this cave gig. Apart from this incident I have finished all dives on loop.

    As a result I haven't had your bad experiences and my own empirical data suggests the units are pretty reliable. As I said before, Id like an OTS counter lung unit for a cave to enable flood recovery. Also I appreciate I haven't been putting my units through the rigors of cave diving. Not that UK wreck diving isn't a fair test of equipment in its self.

    Most anti CCR divers seem to fall in to the group who don't understand/trust CCR and assume they will break down and kill you every five mins.

    Then there are CCR divers like you and Mike who see CCR as unnecessary for a lot of situations.

    I would probably fall into the latter camp if I wasn't so scared of getting lost /stuck down there.

    At the moment this fear considerably outweighs the fear of unit failure

    With experience in caves I will most likely fall into line with your train of thought. Right now having alllllll that gas is a comforting thaught.


    ATB

    Mark

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