CCR dangerous?

[Vtach]

I wouldn't say they scare the hell out of me, but I sure do respect the fact that complacency will get you killed on one of these things very silently.  It definitely is a change of mindset from me from OC (open circuit) diving but I don't see that as a bad thing.  In fact, I wish that I would have had that much respect for OC.  It is something that all divers should take into consideration.  We are diving in a pretty hostile environment and regardless of OC or CCR, if you are unprepared and complacent either can get you into trouble.

There have been some relatively recent advances in rebreather accessories (or standard equipment in some units) that have made some strides in their safety also.  The HUD (heads up display) and BOV (bailout valve) have really helped from a safety perspective.  The HUD is positioned, in most cases, right on the mouthpiece and is easily visible.  The key duty is to alert the diver of a change in PO2 (oxygen level).  This will alert the diver immediately to pay attention to the unit.  The BOV is basically an second stage regulator built into the mouth piece and is operated by a lever or valve in order to go from closed circuit to open circuit in the even of a problem.