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Some questions for all you rebreather pilots...

Discussion in 'Rebreather Diving' started by Nasser, Jul 28, 2014.

  1. Nasser

    Nasser ScubaBoard Supporter ScubaBoard Supporter

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    I’ve been seeing quite a few Closed Circuit Rebreathers on boats lately and finding the technology and diving approach quite fascinating. I know very little about rebreathers except for a very basic understanding of the concept and designs. I've done a search but couldn't really find any specific threads or answers to some of these questions, so perhaps some of you rebreather pilots can share your knowledge:


    1. I understand that CCR’s basically come in three flavors - eCCR or mCCR or hybridCCR… what kind do you choose to currently dive and why? Also what brand of CCR do you use?


    2. How different do you find CCR to Open Circuit in terms of the actual diving technique ? was it a huge learning curve?


    3. Is there anything that you still prefer in open circuit over CCR?


    4. Finally… how safe do you find CCRs in general? are there any brands or types (electronic vs. manual) that you find safer over the other?


    I merely pose these questions for my own better understanding of CCR’s and am not looking to start any debates… just interested in your own personal experiences.


    Many thanks


    cheers,
    nasser
     
    cmulvaney likes this.
  2. tbone1004

    tbone1004 Technical Instructor ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: Greenville, South Carolina, United States
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    you're better off joining rebreather world and reading the articles from the guys over there because the rebreather world is a very very very personal decision.
    The universal answer to 2 is yes, the most skilled OC divers look like hell for the first 10 or so hours on any breather because buoyancy control is very very different than dealing with OC. Kicks, situational awareness, etc is all the same if you are doing it properly, but most divers are not very aware of what's going on around them, certainly not with their equipment, so I guess you could throw that into learning curve
    3. usually this is only the ease of just throwing a reg on and hopping in quickly instead of having to deal with all of the prechecks and sorb packing and what not.
    4. they are only as safe as the diver using it, most all of them on the market now are very very safe if you follow protocols, but accidents happen when people get complacent. They are safer than they were 20 years ago, but many people have been using them for much longer than that with no incident.

    You will open debates on question 1, it's not possible to avoid it. The general consensus now is that if it has Shearwater electronics, it is better than a comparable CCR without it. After that, it is all personal decisions. Join RBW if you're serious about learning about them and read the forums there. You will find a lot of stickies on why people made the decisions they made on their personal rebreather, but like a fancy car, house, or any other expensive toy, people become very loyal to their decision thinking it was better than anything else, the truth is there is no "best" rebreather out there, only the best for you.
     
  3. decompression

    decompression Instructor...seriously...

    # of Dives: 5,000 - ∞
    Location: Victoria, BC, Canada
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    Wow, you are gonna receive some interesting answers here. Many of your questions open debates that are still going. There are some super experienced members on this board so you should get some good insight. My answers are as follows;
    1. I use an Innerspace megalodon (shops, not personally owned) and have used drager dolphin SCR's in the past.
    2. The abilities of a CCR RB diver over the average OC diver demand a very high level, skills such as situational awareness, problem solving (not wrote learning), physiology and decompression theory.
    3. Simplicity and cost. But my OC equip is a different tool that I employ differently.
    4. I believe human error is the major factor and not solely design or engineering. How they are used/maintained is very important in their safety.
     
  4. Dr. Lecter

    Dr. Lecter Solo Diver

    # of Dives: 500 - 999
    Location: NYC/Honolulu
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    My thoughts below.

     
  5. hroark2112

    hroark2112 Tech Instructor

    # of Dives: 0 - 24
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    For me, I dive an mCCR, a Kiss Spirit LTE. I know my personality and I know how my ADD brain works, so for me diving an mCCR is best because I can NOT allow myself to become complacent and reliant on the electronics. I have to keep an eye on my PO2 and have to both know what it is at all times and be able to adjust it when necessary. The fact that there is nothing adding oxygen over and above what the unit adds at all times means I have to have good underwater habits in regards to my loop.

    It is very different from open circuit. I am so glad that my instructor didn't have a video camera operating during my first dive in training, between the faceplant on the training platform when I first descended to the hard knock on the noggin when I ascended from 100' for the first time to the deploying of the safety sausage, I was a mess. I was better on dive 2, but to be honest I still feel like, after almost 50 hours on the unit, that I'm not quite dialed in. I am much better, but I still have plenty to learn.

    I haven't gone back to open circuit yet, and don't plan to except for teaching and on trips where CCR support will not be available. I love the silence of the unit, and I feel that unless I have to go back for some specific reason, I will continue diving the CCR.

    As far as safety, that's definitely driven by the diver. There are things that I do that other CCR divers would think are dangerous, I'm sure. I do follow a checklist when I put the unit together and make sure I do a pre-dive check every time. If I have an issue I feel warrants thumbing the dive, I do so without fail. I've thumbed a few dives so far, mostly due to fairly minor equipment issues, but it's not worth dying just to see a wreck. I don't make modifications to the actual breathing loop of my unit with the exception of changing the mouthpiece, although I have made several minor modifications to the unit that involve weighting and mounting of accessory items & bailout. I don't get in the water with known issues to the breathing loop or electronics, and I don't make substitutions to the vital parts of the unit, even if it means missing a dive.

    All that being said, I fully believe that there are safe eCCR units out there and that some divers have valid reasons for diving what they do. I will never debate my own reasons for my choices, since there's no one out there who will convince me that I'm wrong :) I also will not join in on any of the bashing of units or manufacturers, since this unit is the only one I've ever used and the only one I have real knowledge of. I have opinions of other units, but don't we all have our opinions :)
     
  6. red_barbarian

    red_barbarian Solo Diver

    # of Dives: 1,000 - 2,499
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    Go try a few and it will help you have a better feel for what folks are talking about.
     
  7. dreamdive

    dreamdive Rebreather Pilot

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    Hello Nasser,

    You are asking questions that are much more easily answered in a conversation than writing it! You said you checked out a bunch of resources but did you also check the AddHelium.com website? They have all kinds of information, articles, etc. If you ever get a chance to come to Florida, they have a showroom featuring 14 or so different rebreathers and can give you the ins and outs on all of them.

    You may also want to keep in mind that most rebreather divers are certified on only one, maybe two different units. Personal bias will play big when he/she is explaining his/her experience on that unit. There are many different units out there offering different features. I am certified on seven different units right now and found that to be quite enlightening.

    Now to my personal bias: I love diving CCR and dive deep or shallow with it. I avoid diving OC. I dive a hybrid, and eCCR while practicing mCCR all the time (You can dive mCCR with an eCCR but not eCCR with an mCCR - sometimes I use the eCCR function as a back-up). To explain why would take too long. There are front mounted counter lungs and back mounted counter lungs and each has its advantages and disadvantages. However, that being said, I find the rEvo or the Pathfinder great starter units. That being said, I have been shallow and deep (>450 feet) with both of them.

    The learning curve you will experience is largely dependent on the instructor and your aptitude. Learning to manage loop volume is initially the "biggest" difference but depending on your aptitude and your instructor an easily learned skill. Like any new skill, it will require practice to perfect (I got excellent at it during my cave training - out of necessity)

    Finally some food for thought: How many people have ever pointed out all the lives saved on CCR? All we hear that it is dangerous. Given the dives I have on CCR, I feel safer CCR than OC any day! I have options on CCR that I don't have OC.........Again, too many reasons to list in a forum setting.

    I will also say that you can be pretty sloppy with your OC gear and get away with it. Not so with CCR. It is a LIFE-SUPPORT UNIT and should be treated with respect. Maintenance is required as is vigilance before, during, and after the dive.

    Good Luck on your search and hope to welcome you to the bubbles divers someday if you choose to go that route.

    Claudia
     
    Nasser and lv2dive like this.
  8. Nasser

    Nasser ScubaBoard Supporter ScubaBoard Supporter

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    Wow you guys are fast!

    Some excellent feedback so far and exactly the kind of info I'm looking for. Indeed, these are probably lengthy discussions and I do realize that rebreathers are a very personal choice for various reasons... but it is really interesting to get different perspectives and experiences from all of you. I have actually visited Rebreahter World and CCR Explorers as well, but seeing that this is a very dynamic community here at Scubaboard I thought I would solicit some of your opinions over here too. (i'm sure most of you are members of those forums as well)

    So far so good - it's all very helpful and much appreciated. Keep it coming pilots ! :pilot:
     
  9. 2cold4california

    2cold4california Nassau Grouper

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    This is the only question in this thread i can answer, so ill try.


    CCR is great in that it ameliorates the issue of gas consumption at depth, and this gives divers the option to go to depths that are simply not maintainable on OC. Well, most people don't have CCRs or know how to use them, so as soon as soon-to-be John/Jane Doe goes and dives past 150M or so, nobody can go down to get him.

    CCR does nothing to prevent DCS, and in fact makes it far more likely by prolonging your dive. The gas mix is what prevents DCS. CCR will put you down at depths where it would take 20 AL80s to get one diver down to you for a few minutes. While prolonging your breathing time does allow you to use less gas to decompress, you aren't decompressing any LESS than the diver who hypothetically used 20 AL 80s to do the same dive.

    I think people would a agree that a 12 hour dive to 200M on OC is unsafe. Well, its actually just as safe as a CCR dive it's just way more logistically complicated and expensive. Your decompression time would be the same if you had a OC rig with a magical AL900 tank.

    So basically, yeah CCR does save lives, but the lives it saved were probably put in danger by using CCR in the first place.
     
  10. Dr. Lecter

    Dr. Lecter Solo Diver

    # of Dives: 500 - 999
    Location: NYC/Honolulu
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    Spoken like someone without much understanding of the topic. What's your CCR experience, again? And who's going to be getting down to an OC diver at 260' even? You're just as easy to assist on a CCR as on OC: either you can get off the bottom and maybe signal someone on the boat to assist with extra deco bottles via a note on your SMB, or, you can't and you're beyond help.

    The main safety advantage of a CCR is time. Short of the loop failing, you have time to solve problems and time to decompress from that overstay. Read the account (pretty sure it was in Bernie Chowdhurdy's book) of a NE wreck diver who became lost in a large wreck (maybe the Stolt, I don't recall) due to a silt out.

    Rather than bumble around in the dark and likely getting lost even deeper, he hunkered down on his RB and waited it out. For hours. When he could see well enough to exit, he did. On the loop, the whole way.
     
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