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Thread: The ART of rebreather -DIR compliant CCR

  1. #1
    RBW Member tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining's Avatar
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    The ART of rebreather -DIR compliant CCR

    Hi All,

    I have been diving a DIR / team diving way for a few years now on OC and have configured several CCR over the years trying to make them DIR compliant using Megs and now my JJ-CCR I have also had the pleasure of teaching GUE instructors and other DIR minded folk over the years. So my Q. is this what makes a DIR Rebreather /Diver?
    Struggling with the idea diving the long hose and all my bailout gas on my back I asked myself do I really need to configure in a Hogarthian way to be team diving with efficient skills and simplified planning?

    My thoughts are as Follows:
    The Rig

    •The unit should allow for large volume On-board bailout gas supply cylinder to be fitted, not necessarily all diluent on-board, as I like the idea I can pass off BTM mix to a team member in an emergency and not have to long hose gas share in complex dives. I really believe in having larger volume diluent tanks fitted to the rig to simplify bailout, loop flushes, cell checks and Rescue if required. So I decided to continue to carry reserve gas in a stage bailout that can be passed off in an out of gas emergency and remove the long hose and use a larger single supply diluent tank routed to my Bailout valve, maintaining the CCR standard of O2 right (On-board) and diluent supply on the left.
    •The units I dive are fitted with a built in bailout valve/ BOV and routed to a cylinder with enough capacity to mage a personal bailout without going to a stage unless required due to primary system failure
    •I felt I needed a back mounted Lung system allowing a clean chest area for streamlining the rig dealing with light cords and allowing easy access to my chest D-rings for stage manipulation and back up light deployment.
    •My configuration must be equipped with both oxygen and diluent supply manual bypass systems
    •The units should be able to accept off-board pluggable gas encase of primary supply failure .
    •The unit should be fitted with a back up system monitor
    •The system should be maintainable without any special tools and should be in the field repairable
    •The unit should have undergone independent testing to validate unit performance.
    •The unit should trim out well without the need for lots of additional weight to allow for streamlining in overhead environments.

    The rigs I see fit this configuration are the Meg, JJ-CCR, Hammerhead all electronic!! As the pilot I choose to manually add gas to target PO2 overriding the electronic set-point and using it as a parachute /ABS breaks if required. This way I am in control of my PPO2, loop volume and should I need to go OC via the BOV no gas is entering the loop causing buoyancy problems while I deal with the emergency. It totally works with MCCR or Hybrid as well, so long as its easy to isolate O2 flow into the unit if its required to go to OC to prevent buoyancy loss.

    Team diving generally then considers diving standard gases.

    It made sense that adopting existing standard gases I Had been taught used by DIR divers already and modifying the MOD of the gases to ensure I can flush the loop to verify PO2 at depth or during toxic loop.
    The gases and operating range is then as follows with a note that the dive plan target depth should not exceed a PPO2 of 1.2 and provides a 30m END or shallower.

    lhttp://www.rebreatherworld.com/attachment.php?attachmentid=23914&stc=1&d=1308215292

    Decompression gasses follow the standard gas format using, 21/35, 35/25, 50 and Oxygen for Open Circuit bailout plans.

    I believe there are lots of advantages to using standard gases in CCR operation as it simplifies team bailout, streamlines gas blending and ensure straight forward bailout dive planning allowing ratio concepts for on the fly deco at reasonable shallow depths and range.
    Diving standard gases aids the divers as they learn the gases and profiles like the back of their hand as each diver can then provide backup in decompression management and bailout situations to a team member under stress as they are also very clear with the plans and procedures.

    It's not my intention to provide a detailed planning session in this post but the idea is then that I apply minimum gas volumes to a slightly higher breathing rate, assuming a CO2 hit as a possible situation and manage decompression schedules with trusted dive planners like V-Planner of G/F based software. It is then easy enough to apply a pragmatic approach and derive ratio concepts from the data.

    It occurred to me that having taught and dived with a reasonable amount of CCR divers there is often no common ground when it comes to dealing with emergencies, I know theirs more than one way to skin a cat but I think it makes sense if we all kind of share the same approach, I am quite sure we could all drive if the clutch took the position of the brake but if every time we got in the car we had to work out which way round they are it might get messy. I have been working on some skill sets and when I am fished editing I will post them for thoughts and comments.

    I also felt that Pre-dive can be a stressful time, have I done all my checks, do I have all my gear what’s the plan again? All this needs to be simplified into following the manufactures specified gear checklist and then conducting a full head to toe check with brief overview of the plan, GUE do this with the EDGE I have done it with MONA LISA (after all theirs and ART to this madness).

    M - Mission
    Dive objectives.
    O - Organization
    Define the roles in the team
    N - Navigation
    Direction
    A – Ascent Profile
    Depth & time & Deco
    L- Linearity Check
    Oxygen cell flush at 6m
    I – Inert gas mixtures
    On-board mixes & bailout gases
    S - Setpoint
    Descent, BTM, Ascent
    A – Apparatus
    Head to toe equipment check

    The idea being each diver in the team follows along as a team leader chairs the brief, the divers each confirm equipment operation and highlight functions of key components like how to operate the BOV and manually add or flush gas into the diver loop. It also helps as a last minute reminder of the dive plan details from the detailed briefing.

    There are lots of other things that make a true CCR teammate including experience, situational awareness and Physical ability for the level of diving.
    I can honestly say that since I started to Re-think my CCR diving and integrate the team concept into my CCR dives I have felt happier in many ways ultimately making me feel safer as a diver and a teammate diving CCR.

    It would be great to here what others have done to integrate CCR into a team diving philosophy or if you’re an open circuit diver diving following dir principles and feel you would like to move toward diving a rebreather and maintaining a team approach.

    Safe Diving
    Last edited by tecdivertraining; 16th June 2011 at 10:20.

  2. #2
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    Re: The ART of rebreather -DIR compliant CCR

    i have done only a few oc deep dives , at this divs my plan was to dive a clear configuration, the dir guys tell wich reg`s, wich drysuit, wich gases and so on, for me it was important that my configuration is clear and all parts are secured on the best place, i rig my stages like the dir guys do it, because i think this is a god idea and the setup is clean and my buddy can see where is the reg, what is in the tank and what is the mod, and at the last trip to france where we have arround 25 stage tanks in the water to see witch stage`s are mine (with my label on it) is not so bad !!! that`s a safety feature for me, but i have used poseidon and apeks and scubapro regs, and both of them are (in germany) not dir conform..........,

    i have had a discussion with a (dir style diving) instructor that he can not dive with me because i have poseidon stickers on my double 12`s,......

    when i switch to ccr it was and is important for me that my rig is clear and all parts are on the same place like on my oc rig, now i use fmcl`s, ok but i can dive with up to 4 stage`s on the left and have my oxygen on the right (like the onboard tanks), the clear chest is a benefit when oc but at the moment i dont want switch to bmcl,

    i am not sure about the standart gases, for me it is a little bit different to dive with oc and ccr together and everbody dive the same gases, but i think it is possible that all divers in a team have approx. the same gase, for emergency and bailout scenarios,

    when you do a google search i think you will not find only one statistic that said, diving dir style is safe than diving not dir style,..................

    when i dive (not important what kind of diving) i like a tidy, clean and easy setup where i can reach all my parts by myself, when this is dir style ok but i am not a dir guru, i think it is important to have guys like you who have the time to do some brain work and can test all their thoughts and then do the brain work again,.....many thanks for that and great and safe dives while testing

  3. #3
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    Re: The ART of rebreather -DIR compliant CCR

    Interesting you don't mention the Pelagian, don't appear to consider the possibility that NO off the shelf Rb would meet all your requirements and that a "self built" hybrid might be the way forward.

    The Pelagian seems to be the closest unit to what you're looking for with it's standard needle valve but the needle valve can be used on other systems.

    Overall though, and this only my view, the philosophy you espouse it too prescriptive. It presumes that everyone can be handled by process or a standard when of course the real world, repeatedly demonstrates that that is not the case quite often.

    I can accept that certain basic principles such as (rich on the right, lean on the left for example) make sense but you very quickly get to a point where some people "wonder why do we all have to have pink fins"? In other words, you might really love the JJ, someone else might want a HH or a Meg and some other silly bugger wants an inspiration with a needle valve, HH electronics and SDS can....

    CCR's certainly do one thing very well, they bring the "I'd rather fight to the death than switch" mentality out in bucket loads don't they?

  4. #4
    RBW Member tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining's Avatar
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    Re: The ART of rebreather -DIR compliant CCR

    Quote Originally Posted by osiris  View Original Post
    Interesting

    The Pelagian seems to be the closest unit to what you're looking for with it's standard needle valve but the needle valve can be used on other systems.
    Interesting you mention the Palagian and its valve Andy supplied me one around a month ago, its fitted to my JJ at the moment so I can test out if I like it or not so far Im on the fence!

    The units to my knowledge has never undergone third party testing and does not have back mounted lungs,

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    Re: The ART of rebreather -DIR compliant CCR

    Quote Originally Posted by tecdivertraining  View Original Post
    Interesting you mention the Palagian and its valve Andy supplied me one around a month ago, its fitted to my JJ at the moment so I can test out if I like it or not so far Im on the fence!

    The units to my knowledge has never undergone third party testing and does not have back mounted lungs,
    Neither has the KISS been "certified". And neither does the Inspiration have BMCLs off the shelf....mine does though. and it has a Pelagian vlave. And Hammerhead electronics. and an SDS can. Which brings me back to my earlier view - perhaps no "off the shelf" unit does everything you want it to do, so you either live with it's short comings or you change it....

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    RBW Member tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining's Avatar
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    Re: The ART of rebreather -DIR compliant CCR

    Quote Originally Posted by osiris  View Original Post
    Neither has the KISS been "certified". And neither does the Inspiration have BMCLs off the shelf....mine does though. and it has a Pelagian vlave. And Hammerhead electronics. and an SDS can. Which brings me back to my earlier view - perhaps no "off the shelf" unit does everything you want it to do, so you either live with it's short comings or you change it....

    Sure units tend to have "sortcomings" I am just not to happy to change major design factors like Lungs, Electronics, scrubbers without testing (that is unless it free of charge and im testing it)

    If i just brought a 100 grand motor and decided to change the breaks from new I brought the wrong car, but if I fancy sport seats and satnav to make the thing more sporty i doubt It would have a major effect on the safety of the vehicle.

    The unit In my consideration have been tested with this configuration its just cosmetics Im changing from stock tested configuration so im not potentially effecting WOB, scrubber duration /role off or other critical need to knows about unit performance.

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    Re: The ART of rebreather -DIR compliant CCR

    Just to say that correct MONA LISA versus DIRebreather is :

    Mission - Team
    Oxygen - Setpoint - % CNS
    Nitrogen - Narcose - END
    Absorbant - Scrubber left time
    Level of confort - T° - Effot
    Inert Gas - Deco strategy
    Stock of gas - CCR / Bailout
    Assistance - Support

  8. #8
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    Re: The ART of rebreather -DIR compliant CCR

    Quote Originally Posted by tecdivertraining  View Original Post
    S
    If i just brought a 100 grand motor and decided to change the breaks from new I brought the wrong car,
    Not at all. It just might mean that there was no right car on the market.

    There are plenty of people who buy a 100K car tear it apart spend another $100K on it and have something that is a huge improvement over stock.

    Same goes with CCR's.

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    RBW Member tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining is a name known to all tecdivertraining's Avatar
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    Re: The ART of rebreather -DIR compliant CCR

    Quote Originally Posted by Packhorse  View Original Post
    Not at all. It just might mean that there was no right car on the market.

    There are plenty of people who buy a 100K car tear it apart spend another $100K on it and have something that is a huge improvement over stock.

    Same goes with CCR's.
    The folks who buys these cars and do this are not usually the mechanics doing the work they tend to pay specialist / Companies who then do quite a few checks to confirm road /race worthiness.

    When I got my first car I modified it but I didn't plan to enter the F1 with it, I left that to my buddy

    Thats not to say a few individuals with lots of cash and interest in modifications for pleasure or sport do not work on their own but im confident their the minority

    When I first got into Rebreathers it was modification galore on my Dolphins and that proved good grounding for my CCR days, that said I made some stupid mistakes that could have killed me back then.

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    Re: The ART of rebreather -DIR compliant CCR

    You asked for comments :D

    I really don't understand the fear of electronics. To continue the car analogy, I could count lamp-posts against a stopwatch, start the engine with a handcrank and use my spare foot to pump the diesel and adjust the air intake. On the other hand I find it a lot easier to just let the automation do it for me whilst watching it all. It doesn't make me a passenger.

    I really don't see how any contemporary CCR fits in with the DIR philosophy. The failure modes & design preclude the really important basic holistic approach, the rest is just an exercise in grafting team diving and (to my mind) arbitrary kit configs on to CCR rigs. I'm not saying that's a bad thing but it isn't DIR. I would never say I dived DIR but I certainly dived hogarthian when i was OC and to my way of thinking the only units that ever approached that holistic philosophy is the Mk15x series, especially running the old analogue Rev G pods, but even that's still a long way from what I'd say worked. The basic premise of relying on galvanic cells and chalk is all a bit too Flintstones for me.

    While the deco gas choices might be optimal for use on OC, I don't think they are necessaily the best choice for CCR. I went through a similar exercise when I first went to a rebreather and always seemed to be carrying more cylinders than for the equivalent dive done on OC for the simple fact that you can't get away from carrying the unit (as an OC diver would carry a twinset) plus you are carrying deep bailout as well. You're always going to be carrying at least one more bottle if you follow the DIR recommendations. If OC deco is a regular part of the dive then the gases make sense, when it's a last ditch, get me back to the surface compromise then I think there are better gas choices that make better use of gas volumes and cylinder numbers.

    There's a lot to be gained from better discipline and procedures but I don't think any CCR will ever be DIR. Well, until it suits a few GUE gurus then they'll find whatever justification they need to call it DIR officially.

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