Thread: Tanks vs breath hold lets get your thoughts.

Originally Posted by gadgetman

What are these breather things?

They've been around longer then Open Circuit. They come in a few flavours but basically all have an ambient breathing loop incorporating a scrubber to remove CO2 and a counter-lung that is basically a flexible reservoir that opposes your lungs.

SCR = Semi Closed Rebreather about 8 times more efficient than Open Circuit, runs on a fixed percentage of Nitrox so the O2 partial pressure varies with depth. The SCR trickles Nitrox into the breathing loop at a fixed rate, so there is some wastage being vented out of the loop as you're only consuming the O2 and the Nitrox has other gas constituents that you don't use.

CCR = Closed Circuit Rebreather about 25 times more efficient than Open Circuit, mixes pure O2 with a diluent (usually Nitrogen or Helium based mixes) and maintains a fixed O2 partial pressure regardless of depth. The CCR only injects O2 when required to maintain the O2 partial pressure at the set-point. Very little excess because you're body is consuming the O2 at very close to the same rate as it's being injected.

this is me on the Canterbury...