Article: Redundant Air Systems

[drbill]

As a solo diver, I would never consider something like a Spare Air. However, your article pointed out something I hadn't thought of. A buddy diver using a Spare Air to reach their buddy, then breathing off their octo makes sense. I used to dive with a 13 cu ft pony, but now use a 19 cu ft pony and will probably be using side mounted doubles on my deeper dives in the future.

 

[Doppler]

First step in managing OOA situations is having the knowledge to PLAN gas consumption prior to the dive and then to match that to the volume of gas in one's primary cylinders. In other words, the answer is not kit but better training and dive practices.

I also would dispute your findings regarding the volume of gas needed for a controlled ascent from recreational depths... between 18 and 30 metres (60 - 100 feet). During research in which I participated, we found a volume of slightly more than 400 litres (about 14 cubic feet) was the MINIMUM that allowed for increased breathing rates, an ascent at 9 metres per minute (30 feet), a safety stop for three minutes and getting sorted on the surface. Anything holding less is not something I'd recommend.

Also, just out of interest, should there be any conflict of interest disclaimer on this review?

 

[elmer fudd]

First step in managing OOA situations is having the knowledge to PLAN gas consumption prior to the dive and then to match that to the volume of gas in one's primary cylinders. In other words, the answer is not kit but better training and dive practices.

I also would dispute your findings regarding the volume of gas needed for a controlled ascent from recreational depths... between 18 and 30 metres (60 - 100 feet). During research in which I participated, we found a volume of slightly more than 400 litres (about 14 cubic feet) was the MINIMUM that allowed for increased breathing rates, an ascent at 9 metres per minute (30 feet), a safety stop for three minutes and getting sorted on the surface. Anything holding less is not something I'd recommend.

Also, just out of interest, should there be any conflict of interest disclaimer on this review?

The other thing people should keep in mind is that the size of your pony needs to go up exponentially with depth. I'd have no worries making an ascent from a 40' dive with a Spare Air. From 130' though 19 cf would be my minimum and I'd prefer a 30.