mCCR vs eCCR Rebreathers | SCUBA 101

In the fifth installment of the Rebreather series, Jonathan gets into the nitty gritty explaining the differences between the manual CCR (mCCR) and the electronic CCR (eCCR). Get ready for a lot of information!

PLEASE NOTE this video is for informational and entertainment purposes. This is not a substitute for proper training!

#rebreather #scubadiving #scuba
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[Gilgwathir]

I'm here because I wondered how a rebreather works as I came across the concept in Subnautica. Now I'm four 30min videos deep in this rabbit hole 😂

[YukonSeanHolland]

This has been a great series Johnathon!! Thank you!!

[seangates]

Thanks for the presentation (and great artwork). I'm probably never going to dive a rebreather but I'm an information junkie so there you go. Of all the folks posting scuba videos, I think yours are among the most engaging to watch.

[connorvenegas]

Thank you for the breakdown! I’m looking in getting into CCR diving sometime within the next few years.

[CFSTB]

Thanks for these videos. As a 24 year industrial instrument mechanic, I have seen an incredible increase in reliability of instrumentation, to the point where I do far less repairs and way too much PM's (preventative maintenance, or basically just check it out) and not much in the way of repairs. Solenoid valves when in a clean atmosphere with clean flow, they are exceptionally reliable, but gas sensors still drift over time and do require calibration and at some point, replacement. In our environment we mostly measure toxic gases, but we also measure O2, because even if there are no poisonous gases we still need the stuff.
In my experience, I seldom have to replace the O2 sensors compared to an LEL or H2s sensor, but I do need to calibrate them more often.
But I would still, without hesitation, trust my life to an assorted collection of instrumentation assembled by the lowest bidder, hired by a one of these companies to build a reliable rebreather unit.
But that could be because, as I near retirement age, I would consider one incredible dive in an incredible place to be worth the price of

[chunnyj]

Great video and explanation. Cant wait for another tech video to come out!!

[DKCGamerGirl]

I love this series on rebreathers! Super informative and well explained as always! Looking forward to the next episode to hear how the oxygen sensor works! 😉

[DontScareTheFish]

Great explanation. The only point I'd make about CCR's is in the beginning you're explaining it in FO2 terms rather than ppO2 terms. I understand that's probably due to the audience these video's are targeted at.

For anyone making the switch or thinking of and reading this comment, when you're diving CCR you no longer think of the fraction (or percentage) of O2. Instead you're thinking of the partial pressure of O2. In OC scuba the fraction of O2 is constant which means the partial pressure of O2 changes with depth. With a CCR the partial pressure of O2 is held constant with the fractions (percentages) changing.

[ReediusMaximus]

Thank you so much for the information. I found you from watching Dive Talk and you guys at Blue World are Awesome!!

[terryhill]

man i was thinking, too many notes, but you explained that very well, I get it, am 70 so I am not ever going to dive, I will watch videos, I started with dive talk guys, and seen you there, I cant even craw under the house with out panicking, so I call ghost busters

[rodolfoborrel]

Your series of videos "All about rebreathers" are absolutely perfect! I'm a technical diver starting to think about rebreathers and these videos was excellent as a first step to know an overview about it. Congratulations 👏🏻

[twilightface]

I think this is called an "instant like situation" !

[scubacro]

I'm looking into ECCR becouse I live in Croatia and we have a lott of beautifull wrecks, but best wrecks are very deep, 60m - 120m. I asked my instructor why he chose ECCR and not MCCR he just said, "if something goes wrong with rebreather f*** it just close the loop and go on bailout", he has been diving 40+ years, still alive and diving never entered baro chamber, so his logic must work😂

[pricediver]

Is mCCR stands for mechanical rebreather or Manual rebreather? I thought it is mechanical rebreather

[maxtorque]

2nd question: with either system, significant changes in depth lead to changes in loop gas mass to hold the average loop volume constant. So climbing up over a reef by 20 feet is going to require you to vent system gas and dropping down the other side is going to trigger the value to add more diluent. In these circumstances neither the eCCR or the mCCR can hold a constant PPO2 can they?

[maxtorque]

Surely the "best" of both worlds is an eCCR with a constant flow valve as well? ie a backup to the electronic solenoid?
Given the most likely failure by some margin is an oygen sensor failure, i suspect neither system is actually "more reliable", especially when human factors dominant CCR diving incidents?

[RicoB-ndABN]

How about having 1 tank that is 100% O2 and then the diluent bottle a mixture 50/50 blend of Nitrogen and Helium? Wouldn't that reduce the Nitrogen levels even more?

[MorganBrown]

How does a dive computer sense PO2? You mentioned that the computer gives a measurement independent of the oxygen sensor in the loop. Or did I misunderstand?

[suyvik]

So, what about all that extra air coming into the system (o2+diluent ), goes? This means that it bubble???? Very interesting by the way, I have some diving training and medical training. But with this lessons I have more questions lol… thanks… lll keep watching …

[HL]

(non-diver here)
[Why not both? A trickle valve AND a computer that adds more if needed.] aaaand the video said exactly what I thought...
And the depth change PO2 problem could be easily solved in software.
5k for a microcontroller and a valve??? That sounds a bit too expensive...