In the 2008 STDA has been the first diving school and then agency to introduce the standard and procedures of the 'flying connection' to the bottom mix & deco bail-out tanks. This standard and procedures have been developed during the years and are part of the holistic rebreather training system of STDA. From 2005 Marco Valenti has started to develop specific decompression procedures with CCR puting them in STDA rebreather programs. The decompression system works in the range of 0-130 mts and actually it seems to have reach the limit.
Only few and selected CCR are considered in STDA training; they must have:
- 2 redundant display with 2 indipendent power supply; in case of a display and HUD, at least a 'stand alone' CCR computer is requested
- manual oxygen injection on exhale conterlung,
- Front Mounted CounterLungs (FMCL) suggested
- BOV (suggested Golem Gear IQSub BOV type that allows the reverse diluent flush of the loop)
Currently STDA doesn't propose decompression training courses with eCCR rebreathers designed with only one display/electronic and the HUD (in this case at least a stand alone computer is needed), and/or with the oxygen manual valve on the inhale counterlung.
In our opinion:
- support the concept that during a decompression dive the HUD is enough to manage the emergency of the failure of the only one electronic/display is a falsehood, that can only help the manufacturer to keep the rebreather cost lower;
- support the concept that a rebreather with the oxygen manual valve on the inhale counterlung is safe, it's a falsehood
- support that backmounted CL have the same safety level in managing emergency and safety drills than on the shoulder CL it's an other falsehood: this concept has to be very clear to each STDA CCR instructor and has to be explained to CCR diver that chooses the backmounted option, using the STDA comparative table
These points are derived from the simple observations of problems and accidents directly and indirectly observed in water during years of training (since 2005) and dives that have highlighted the problems leaving no room for doubts.
This does not exclude that in the future design improvements can lead to reconsider things.