[quote=Ben Field;182937]
Quote: (Originally Posted by
henckell)
A recreational unit wouldn't need twin O2 tanks or regs. Normally the fixed IP on a manual Rebreather allows depths down to around 100 meters, well outside the recreational boundaries. If one O2 delivery system fails for some reason, it could have failed anyway using either only manual or only electronic control. The only reason for using twin O2 tanks/regs would be redundancy, which is usually not standard on any rig. You check your PO2 now and then and it's always possible to fly manually without any "O2-addition-aid".[/quote
I think your missed my point- I was saying that two tanks is unecessary but I don't see how you can supply 11-12.5bar fixed IP for a Orifice and 7-8bar balanced for solenoid without complication or >insert magical new device<
The fixed IP might allow 100mtrs+ but I (and others I assume) need that flow rate shallower for the KISS principle to work, so I can't reduce it to allow for a solenoid...
Mounting a second o2 tank isn't actually so difficult,
and as I see it it would give you the advantage that you can shut one system down without effecting the other, in particular with a stuck open solenoide.
This would even make the configuration change between mCCr, eCCr and hCCR not even a matter of 5 minutes, but just seconds ( turning tank on /off), this would mean that if you want to go deeper you could descent past the mCCR limitation as well, the eCCR would take over.
As i see it the eCCR is not the parachute to the mCCR, but the other way around. eCCRs are comfortable to dive, but they fail, you do have to monitor them constantly, just listening for the solenoide to kick in is i think not enough.
On another note a second tank would mean you get away with lower pressure o2 fills as well. and as i am really really tight and dont want to pay for a booster pump, nor the LDS for boosting my tanks this could allow me to suck my g of O2 empty to a lower pressure. Did I mention that I am really tight - dont like to retunr half empty 02 tanks to BOC.
So for me a hybrid would make sense, as a electronic failure wouldn't ground me form diving,
I still have to monitor the systems closely, therefore a po2 meter whcih is not part of teh eCCR would be my preference ( this woudl keep the monitoring between mCCR and eCCR seperat) - so truly two systems.
I could get away with less pressure in my 02 tanks, and at the end wouldn't have the mCCR limitations.
But these are only my .02