IN today’s diving world, electronic closed-circuit rebreathers (CCRs) are the ultimate big boys’ toys. But they are much, much more than cool status symbols.
On a CCR, a three-hour no-decompression dive is within the scope of any diver with reasonable skills. The diver’s open circuit breathing rate is irrelevant on closed circuit as the unit is designed to ensure that you are breathing the optimum gas mixture at every depth. Typically, at 30 metres, you will be breathing a low Nitrox mix, around 32 percent. At 16m or so, your breathing gas will be Nitrox 50 and by the time you are doing your safety stop, the mix will be close to 100 percent O2.
However, there is a price to pay for these rewards. You must respect your unit, maintain it meticulously and understand completely all the ways in which the CCR can hurt you.
Here are eight Closed-Circuit Rebreather Dos & Don’ts
DO always know your PO2. Always!
DON’T trust your brain more than the laws of physics. DON’T trust your electronics more than your brain.
DO use a physical checklist when setting up your unit. DO calibrate your oxygen sensors as if your life depends on them. It does.
DO change your CO2 absorbent frequently and before you have to.
DON’T give-in to peer pressure. It’s YOUR life, nobody else’s. Finally…
DO know that you are certainly less capable than you think you are.