Quote: (Originally Posted by
Genesis)
This is kinda like the argument I've gotten into over cave diving when you donate gas. There's a "dogma" that says you show the donee your SPG so he knows how much gas you have, and you look at it too.
Why? Either you have enough to get out, or you don't. If you don't you're dead. If its marginal knowing 20 minutes ahead of time that you may be dead is likely to make it happen!
What about the gas volume is marginal to get both of you out of the cave if everyone to remain calm, or even have to skip-breath a bit, to conserve the gas instead of getting all excited and huffing like crazy ?
By knowing that it is critical to conserve gas and try not to do any unnessary wastage manuever, it will help instead just exiting blindly in an emergency situation.
Running out of O2 on a CCR isn't (and shouldn't be) a life-threatening event. However, by knowing that it is going to happen (i.e. via the SPG), the diver anticipates it, prepares multiple contigency back-up options to be ready and executes them with no stress.
By comparison, some divers might be stressed with alarms going off without knowing exactly where the problem source is. Depending on the experience level, there will be a delay in reaction which could add to the chance of something worse to happen.
And depending on the unit, there might not be any alarm. Couple that with a busy diver will gravitate the situation.
At the end of the day, people dive without gauges know the risk and have worked out plans to overcome the issue. This has been discussed extensively on the other thread.
Since you will not be taking any training course diving your home-built unit, it might be wise to dive with as much information as possible as many things COULD go wrong until you work out all of the bugs. We all
think we could handle anything thrown at us, but some people react differently in the real world.