CCR Selection priorities

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there’s no arguing that saying “work of breathing is great” without testing and data to back it up is anything other than subjective. However, having dealt with several manufacturers at the training agency level who were trying to get through the CE process, I can promise that a CE certification (at least for a rebreather) has very little to do with actual performance or safety.
Jon, all EN14143 aka CE certification is is a minimum threshold or sub-maximal barrier to entry to at least provide some proof that the rebreather in question meets at least the very barest minimum standard. See Gavin Anthony's DAN presentation on this pg218 https://www.diversalertnetwork.org/files/Tech_Proceedings_Feb2010.pdf

There's plenty of rebreathers on the market with CE that don't have great WOB as meeting the 2.75J/L requirement isn't hard. Beating the lowest WOB option for a rebreather at 1.44J/L at 40m on air at 75lpm is a tad harder.
But then that is also just one test out of 52 odd.

However another consideration is if you have to take parts off the rebreather to get it to pass the testing does that make a mockery of the process. Quite probably. It also completely and utterly negates direct side by side comparison of the results for studies like yours; unless you know both or all systems were tested to the exact same standard ie. with BCD fitted and potentially inflated as an example.

But looking at the more esoteric element of rebreather selection you might want to consider:
The products FMECA Deep Life Design Team: Design Submission for Open Revolution
It's unmanned design validation testing Deep Life Design Team: Selected Design Validation Reports for DL & Open Safety Equipment Ltd's Rebreathers

Flood tolerance is an interesting one for you to mention as there aren't many units on the market that you can flood recover underwater from a full flood and continue on the dive.

Oh and if anyone's diving a Fathom CCR whom wants to drop its WOB in both CC and OC modes, quite happy to sell you an ALVBOV to significantly improve its actual WOB:
https://www.opensafetyglobal.com/Safety_files/DV_DL_ALVBOV_Breathing_Params_A3_100318.pdf
https://www.opensafety.eu/datasheets/ALVBOV_40m_75lpm_air_081014.pdf
 
As for the third party testing, sure, it would be good to have the numbers, but not really very important. None of the individual components In the loop are new design, there’s data out there on the components in similar configurations, which all perform very well.

Thanks for all of your advice so far on the various CCR's that you have taken the time out to write about. However on this point I'd have to disagree. Any CCR is a critical life support system and your extrapolation equates to designing and building a new helicopter from other helicopter components and that because all of the components were previously tested in other helicopters then the new helicopter does not need testing.

Unfortunately thats not how systems work. And as a life support system, for both the enduser's safety and for the manufacturer's future viability the unit should be third party tested with the results published.

Regards

Cathal
 
Can anyone send me the published third party testing for the KISS Sidewinder?
 
Can anyone send me the published third party testing for the KISS Sidewinder?
Esp in the kerfufflefck botching off a "fit" of cans and counterlung on the body that a few instructors seem to be putting their students into.
 
I just want to say that I am very happy with the level and quality of the discussion that has taken place so far.

I understand that CE testing is expensive and the "one and only one" configuration on the certificate is somewhat limited. I realize the value of CE testing, but I also do not use it as the be-all-end-all. It does appear that CE testing on Fathom will need to be done if the next level of the unit is too be reached.
 
Esp in the kerfufflefck botching off a "fit" of cans and counterlung on the body that a few instructors seem to be putting their students into.

I just read through the Sidewinder manual again and can't find reference to this alleged "kerfufflefck". They must have spelled it differently in the manual! :D
 
One thing I have learned in diving 2 different units (in several different configurations) is that WOB can be significantly impacted by the divers trim and positioning. At least one of my units breathes very easily if I am horizontal (which fortunately is 90%+ of the time) but breathes poorly if I'm in or near a vertical position, like on the surface. It makes waiting for a boat to come pick me up less than fun. Another unit I dive regularly does not have this issue, but one configuration of counterlungs is significantly easier to breathe and is much more comfortable than another.

There is a significant learning curve to diving any rebreather, and just because you're competent on one unit, that does not necessarily mean you're going to be good on another. Each unit has it's own idiosyncrasies and even a minor difference in setting the unit up might mean a big difference in both WOB and comfort level on the unit.

Something else to consider when choosing your first rebreather that has not been mentioned. It is definitely a positive thing to have a local network of divers on the same unit. Obviously you will learn from your instructor how to set up, break down, care for, and dive your unit. However you will not learn everything. Having a local network of quality divers experienced on your unit will help you with all the little things that your instructor may not have told you. Things like setting up your unit for local diving conditions, lessons people have learned "the hard way" over their time diving the unit that you do not now have to learn the hard way, second sets of eyes to help you set up the unit when you have questions, and a local network of divers who should be experienced in fixing the inevitable little things that pop up and have spares on hand is a huge benefit. Of course I did it the hard way, luckily my instructor (as any good instructor should be) has remained available for me over the years, both for additional instruction as well as help with questions I have had in the past.

Choosing between an eCCR and mCCR is a big deal. For me, I chose an mCCR as my first unit because I know how my mind works and I was very concerned that I would quickly become too 'trusting' of the unit and would not pay close enough attention to the important things. Diving an mCCR means that you absolutely must pay attention, all the time, or things will go badly. I didn't get on an eCCR until the proper habits were imprinted to my brain. I still check my computer regularly when diving an eCCR, even if to just satisfy the part of my mind that tells me to check it. Knowing how attentive to details you are, how your mind works, and what your tendencies underwater are all play a part in your choice. It is definitely not something to take for granted in your decision.

The instructor you choose is another huge factor. Being able to communicate with your instructor before and after class is important. How well you are able to learn from him (or her) is also big. Some people are just easier to learn from and some people don't pair up well as student & instructor. How well does your instructor know the unit? Not just the assembly, disassembly, and operation, but the intangibles? Every unit has things that are different than other units, little things that are very important. Can he/she teach you what those things are and why they are important? Can they look at how you dive and help you learn to dive the unit properly? Have they had issues, incidents, accidents, mishaps and are they willing to discuss them with you, as well as what really caused the problems?

The other thing I would consider is how easy is it to contact the manufacturer and actually speak to someone? Both the manufacturers I deal with have always been very responsive when it comes to questions, concerns, ideas, or really anything I have brought up. Sure there have been issues, we are dealing with human beings after all. But from the very beginning of my interactions with them, I have found them to be very helpful and professional. One has gone over and above what I would expect from a manufacturer, especially given that I bought the unit second hand. The level of service I have received from them on this unit significantly exceeds what I would have anticipated.

I know there is a lot to think about when you're choosing a unit. Do your research, ask questions, and make the most educated decision you can make.
 
Can anyone send me the published third party testing for the KISS Sidewinder?

do you want the results for before or after the loop hose spontaneously releases from the scrubber tower?
 
Thanks for all of your advice so far on the various CCR's that you have taken the time out to write about. However on this point I'd have to disagree. Any CCR is a critical life support system and your extrapolation equates to designing and building a new helicopter from other helicopter components and that because all of the components were previously tested in other helicopters then the new helicopter does not need testing.

Unfortunately thats not how systems work. And as a life support system, for both the enduser's safety and for the manufacturer's future viability the unit should be third party tested with the results published.

Regards

Cathal

that’s a good point, however a rebreather breathing loop is just not nearly as complex as your example.

To be more accurate, consider taking 2 identical breathing loops, the only difference being that on of which has a canister that is a different material (Delrin vs aluminum for example). Do you think that there would be any practical difference in the WOB? What about the same situation, except there’s just different electronics on the unit. This is essentially what I’m talking about, the variables just aren’t relevant to the testing, especially considering the testing criteria used for CCRs.

That’s why I suggest getting on the unit and feeling for yourself. There are plenty of units that look great on paper, but after a couple hours in the water you ask the instructor why your diaphragm is sore and they respond with “well, your trim is too flat, it breathes best at about 30 degrees”.
 
Jon, all EN14143 aka CE certification is is a minimum threshold or sub-maximal barrier to entry to at least provide some proof that the rebreather in question meets at least the very barest minimum standard. See Gavin Anthony's DAN presentation on this pg218 https://www.diversalertnetwork.org/files/Tech_Proceedings_Feb2010.pdf

There's plenty of rebreathers on the market with CE that don't have great WOB as meeting the 2.75J/L requirement isn't hard. Beating the lowest WOB option for a rebreather at 1.44J/L at 40m on air at 75lpm is a tad harder.
But then that is also just one test out of 52 odd.

However another consideration is if you have to take parts off the rebreather to get it to pass the testing does that make a mockery of the process. Quite probably. It also completely and utterly negates direct side by side comparison of the results for studies like yours; unless you know both or all systems were tested to the exact same standard ie. with BCD fitted and potentially inflated as an example.

But looking at the more esoteric element of rebreather selection you might want to consider:
The products FMECA Deep Life Design Team: Design Submission for Open Revolution
It's unmanned design validation testing Deep Life Design Team: Selected Design Validation Reports for DL & Open Safety Equipment Ltd's Rebreathers

Flood tolerance is an interesting one for you to mention as there aren't many units on the market that you can flood recover underwater from a full flood and continue on the dive.

Oh and if anyone's diving a Fathom CCR whom wants to drop its WOB in both CC and OC modes, quite happy to sell you an ALVBOV to significantly improve its actual WOB:
https://www.opensafetyglobal.com/Safety_files/DV_DL_ALVBOV_Breathing_Params_A3_100318.pdf
https://www.opensafety.eu/datasheets/ALVBOV_40m_75lpm_air_081014.pdf

thanks Brad, figured you’d show up.

Care to share the extensive testing that the good people from Deep Life conducted on the optima as an expert witness for the Skiles case? That’s a good example of how relevant a lot of the third party testing is. The dog seemed cute, though.
 
https://www.shearwater.com/products/peregrine/

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