Quote: (Originally Posted by magentaseas)
With whats been said in replies to my query (thanks again guys) about getting a SCR, Im now wondering....
The first rebreather were pure oxygen rebreathers used in mining and tunneling.
Those were adapted for use UW early on.
Due to the depths limits of pure oxygen (causing hyperoxia = oxygen poisening) O2 was mixed with air to allow for greater depths. Several SCRs were successfully sold for military use in the 50s. The MK6 SCR was long the mainstay for the US NAVY, well until after Biomarine introduced the CCR1000 and its military version , the MK15. The CCR1000 came to the market in 1969, and was build by several companies under various names. I wrote an article on one of those, Innerspace's Porpoise Pack One from the 70s, which back then retailed for around $30,000 with accessories.
Later CCRs like the MK15.5, UT240 and MK-5p that sold to civilains in the 90s were all between $14,000 and $18,000.
So when Dräger introduced the Dolphin's predecessor in 95 to the recreational market for a few thousand dollars it was a big step forward. They had been building military O2 and semi-closed rebreathers for decades.
The Ray followed in hopes to have a smaller, less expensive and easier to use unit that appealed to resorts.
The Azi is a civilian version of a military rebreather.
The Submatix is just another try keep that market going, and the general layout, case, etc, is "inspired" some of Drägers military SCRs (many of which found their way into civilian hands once the military dumped them).
The RMV keyed system isn't new, either, and offers several advantages over the cmf SCRs above. More consistant fO2 in the loop and increased gas conservation.
None of them needs electronics or power to operate, which appeals to some people, although as pointed out before, O2 monitoring is a rather good idea.
CCRs didn't get affordable until the Inspiration, and that's still a relative term.
The KISS rebreathers did change the equation a bit, by costing less than electronically controlled rebreathers and using O2 monitors as the only electronics.
The idea isn't new, either, but was marketed successfully for the first time.
There are some who argue that the KISS rebreathers aren't really CCRs, rather SCR that usually don't expell gas.
The manual gas addition is constant mass flow not unlike the Drägers, Azi and Submatix. The difference is that those units add more gas than the diver needs, 'burping' the excess. The KISS adds less and pure O2, and needs topping off every once in a while. If you get off the loop without shutting the valve down all of the units will have gas flow into the loop and vent it through their OPVs.
*Running for the bunker
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