SO I went home and I read up on Rebreathers. But when I was doing my research, I found SCR's and CCR's. Now, everything seems to be either ECCR's or MCCR's with absolutely no mention of SCR's except for a few questions about the Dragers.
There's plenty to read up on Dolphins, from online manuals and service manuals to them being featured quite dominantly in several books about rebreathers. That's probably largely due to Dräger being the first manufacturer to offer a "recreational" rebreather in large volume. The Dolphin's predecessor, the Atlantis, hit the market in 1995, two years before the Inspiration. At the time it was truly unique, at around $6500 costing less than half of what the CCRs of the time set you back, much easier to use and actually available to dive.
Now, My Local dive shop still sells the SCR ...
Not the Dolphin for much longer. Dräger has stopped production, Aqualung has stopped distributing Dräger products. So when the last units are off dealer's shelves that'll be it for new units.
There are several other SCRs in production in Europe, the Submatix 100 series in Germany (available as a cmf-SCR, mCCR and e/mCCR), the OMG Azimuth and UBS40 (cmf-SCRs) and the Voyager (also cmf-SCR and mCCR), the latter from Italy.
Also, there are several passive SCR available, the Halcyon RB80 in the US being the best known unit. The high-profile cave explorations by WKPP in the US and EKPP in Europe have resulted in quite some following of the basic design, and there are several manufacturers in Europe building low volume production models.
I am noticing most people go OC - SCR - CCR so I am thinking to myself. WHY? If a SCR will do Rec Depths for 4 hours with little to worry about managing a dilutant or Oxygen Partial pressure.. Why would someone who is doing Rec Diving move from a SCR to a CCR? If the Progression is to move to a CCR, why not just go straight there?
The duration for cmf-SCRs has already been discussed, pSCRs usually extend the duration by a factor of 8:1. CCRs can do considerably better than that, so for people using expensive He mixes they are a very viable (i.e. financially justifiable) option.
The OC-SCR-CCR progression has been heavily debated, I believe it derives more than anything else from the history of recreational rebreathers. Before Dräger, RBs were very few and in between, hard to come by and very, very expensive. Either build in low volume to start out with, or getting in very low volume from military into civilian hands.
The Inspiration changed much of that, and again did the (Classic) Kiss CCR. Many a Dräger diver switched to one of these models and finally got what they bargained for: silent diving and long duration.
These days many divers go straight from OC to CC, though, including myself. Why spend the time, money and effort on a semi-closed RB if it's a CCR you ultimately want to dive? Might as well spend it on a CCR and start getting proficient on it.
Also my Dive shop who does not sell CCR's, tells me that they are dangerous, twice as expensive to purchase and maintain, and are more complicated.
Diving has dangers. Rebreather diving a few more. No matter if they're SC or CC.
Think about it for a moment: As I said in my
reply to the question "What's a rebreather", all rebreathers basically share the same parts. The difference is the gas addition and the gases used.
Mechanical vs electronically, pre-mixed vs self mixing.
Either way things can go south, parts can fail, mistakes be made. Plenty of incidents and accidents over the years on SCR, including fatalities. Any RB is dangerous as the diver using it.
Twice as expensive ... only if the electronics fail. They tend to cost several thousand dollars. Other than that you'll need to pay for 3 cells rather than 1 annually, and batteries. Service every once in a while, depending on model.
And Dräger prices are nothing to sneeze at, either!
As for gas, it depends on your location. Last US prices I paid was SoCal 2006, $10 for a tank of nitrox (up to 40%), $0.50/cf of O2, compressed air free. So $15 for 3ltr CCR tank, and that last a hell of a lot longer than a tank of nitrox, no matter if OC or cmf-SCR.
Sorb costs the same for either. Two first stages to service rather than one, some more O-rings to lube, that sort of thing.
Training costs more, but you'll be spending quite a bit more time under water.
Choose your instructor wisely and it'll be worth every dime.
... but more complicated seems to be true, even for the KISS.
I disagree, the Sport Kiss (pretty much targeting the same buyer as Dräger did) is as easy and more convenient to pre- and post dive. It's about as easy and considerably more comfortable to dive. In addition, spares are not an issue, customer service from Jetsam is excellent, and the quality of the rig is better to start out with.
Moreover, I can do any dive the Dolphin does without having to choose gases and orifices accordingly. Bailout is just a quarter turn of the BOV away, while the Dolphin's inflator integrated second stage leaves some to be desired.
In any way, if you think about it cmf-SCRs and mCCRs operate a lot alike.
Both add gas continually through either an orifice or an adjustable (needle) valve.
The SCR more than you need, dumping the difference. The CCR about as much as you need, with the remainder added manually. Both require checking the flow rate.
There are broad differences between rebreathers, their scrubbers, the electronics they use (and that includes SCRs as you
need to know your pO2!). The before mentioned ExtendAir cartridge is by far the safest and most convenient scrubber out there. Much quicker to fill than the Dräger's. The PRISM's on the other hand will take quite a bit longer to fill.
Electronics, broad, broad range. From basic layout to features, to ease of use.
What is the general take, Why is the SCR the Proverbial "Red Headed Step Child" of the Rebreather world?
Probably because it's a design with lots of limits, just fairly well executed. A decade old product based on a much older design, outdated by current standards. Doesn't offer all that much over OC nitrox and quite a bit less than CC diving on the benefit side while having most of the RB hassles and risks.
As far as e/mCCR are concerned, rEvo II with Shearwater Pursuit and the Hammerhead CCR currently offer this configuration. Either setpoint controller/deco computer can be added to a mCCR, or one of the cmf/manual bypass valves (KISS, Hydrogom, Pelagian, Submatix etc) can be added to an eCCR.
Either way you're adding more stuff, more failure points, more maintenance, more expense to your rebreather. Personal choice if it's worth it.
I highly recommend looking at a couple of the available units out there, trying the ones you like, before buying a shelf warmer just because the shelf happens to be at your LDS.
