Quote:
| Originally Posted by jlwarlow On the last trip I was on (which was 1st after getting my Advanced nitrox cert) I had 50% in a 3L pony. I've since been given some advice for using 36% in my pony so that a) It gives me a safety margin for deco (as long as main cylinder has < 36%) and b) I can bail out to the pony at 30m where's 50% can only bail out <20m |
Hello there
I hope you don't mind me saying but I feel that the advice you were given is flawed, it would appear that you're not able to decide on whether you want a redundant air supply or a deco gas for accelerating your deco.
Trying to get one 3ltr pony bottle and one gas mix to achieve both goals is asking to much, you really need to make a decision and go with it.
Obviously after your recent training you're aware that we need to maximise the o2 window to achieve the accelerated deco that we desire, usually trying to initially achieve a ppo2 of 1.6 bar to flush out the nitrogen.. on 32% this would be in the region of 40m
So we can see that 32% is fundamentally useless as a deco gas unless you're coming up from some
serious depths with
serious obligations and I don't get the impression that that is the case.
I'm not having a go here J, so please don't think I am, I just cannot see the logic of the advice you were given.
Should you be diving in the 30m range with no obligations apart from safety stops then your pony is sufficient
(only just) as a redundant air supply but the fact that you mention taking 'Advanced Nitrox' would indicate that you intend to push depths and or times incurring deco obligations.
If that assumption is correct then you really need to start thinking of a manifolded twinset
(This adds the redundancy and removes the need for an AAS) and then you need to calculate how much gas you would need for the required deco that you intend to complete in the future and I'd be very suprised if a 3ltr pony was anything like enough.
If you intend to dive deeper/longer than consider twins and consider a 7ltr luxfer for deco.
Remember once you
and your buddy have incurred deco obligations then both of you should be carrying enough gas to make sure that you or your buddy can come out on back gas should you lose a deco gas..
Bite the bullet mate, sell your stuff, sell your soul, whatever it takes but if you intend to do more intense diving then go properly equipped, if you can't afford it just yet then wait, the dives will always be there.
Best regards
Dave.