mikedarmody
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What's the best way to rig an ascent bottle? Any suggestions on size, type, reg, gauges, attachments, etc.? Trying to plan ahead but don't want to get to bulky. Function would be an emergency ascent air source.
back-up ascent bottle
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That's a bigger question than you relaize. Why not try a Search on Pony Bottle and Spare Air, and perhaps narrow your question somewhat.
I chose a 19 cf, as it uses the same reg, guage, etc. as a smaller one, for little more money or weight, but gives a large emergency margin.
I used to carry mine hung on the side of my main bottle, but that lead to a major problem. I now have it slung on my side so I can see it and reach it easily and safely.
I chose a 19 cf, as it uses the same reg, guage, etc. as a smaller one, for little more money or weight, but gives a large emergency margin.
I used to carry mine hung on the side of my main bottle, but that lead to a major problem. I now have it slung on my side so I can see it and reach it easily and safely.
There are 2 basic schools of thought (and a LOT of variations).
School of thought number one is back mount the pony if you are a rec diver as it is out of the way and the 2nd stage on the pony will function just like and in place of an octo meaning almost no change in configuration or procedure is required. The major variation here is to use an octo also. The downside is that you cannot access the valve during the dive.
School of thought number 2 is to sling it like a deco bottle. It is a little different and requires more practice for the average rec diver to master and is a bit more in the way during the dive. But it can be handed off and is easier to add for dives where you need it and to leave on boat on dives where you don't as it clips on and off easily rather than being strapped to the main tank. It also leaves the valve accessible and reduces the chance of unexpectedly losing air from the pony.
Everybody agrees that if you are using a pony for an emergency, never consider it in the air planning and everybody also agrees that you should never cut your normal reserve short during the dive just because you know the pony is there.
Almost no one will agree on the appropriate size pony to use. Personally, I don't think anything smaller than a 13 is worth the time and effort. I think a 19 cu ft tank should be the minimum if you go deeper than 60 ft and that a 30 should be the minimum if you deeper than 100 ft. and redundant doubles are in order if you go below 130. It's a conservative view, but when it comes to redundant breathing gas, conservative is good in my opinion.
My thought is that if you sling a pony a 30 makes more sense as they sling as well or better than a 19 for relatively little additional weight and a 30 or 40 will retain some usefulness as a deco bottle if you go the technical route later on.
An SPG is also an area where there may be some disagreement. A regular SPG must be used on a back mounted pony if you want to use one whereas you can use an SPG on a 6" or 7" hose with a slung pony. Or you can use a button gauge, or you can choose to use no SPG at all on the pony.
Personally, my thoughts are that if it is a redundant emergency air source, the SPG is not needed as if you are using the pony you should, by definition, be on your way to the surface and an SPG reading would make no difference - you either have enough gas for the ascent or you don't. So my thought is to check the pressure pre-dive, either with a pressure gauge or with a button gauge on the first stage and then forget about it.
School of thought number one is back mount the pony if you are a rec diver as it is out of the way and the 2nd stage on the pony will function just like and in place of an octo meaning almost no change in configuration or procedure is required. The major variation here is to use an octo also. The downside is that you cannot access the valve during the dive.
School of thought number 2 is to sling it like a deco bottle. It is a little different and requires more practice for the average rec diver to master and is a bit more in the way during the dive. But it can be handed off and is easier to add for dives where you need it and to leave on boat on dives where you don't as it clips on and off easily rather than being strapped to the main tank. It also leaves the valve accessible and reduces the chance of unexpectedly losing air from the pony.
Everybody agrees that if you are using a pony for an emergency, never consider it in the air planning and everybody also agrees that you should never cut your normal reserve short during the dive just because you know the pony is there.
Almost no one will agree on the appropriate size pony to use. Personally, I don't think anything smaller than a 13 is worth the time and effort. I think a 19 cu ft tank should be the minimum if you go deeper than 60 ft and that a 30 should be the minimum if you deeper than 100 ft. and redundant doubles are in order if you go below 130. It's a conservative view, but when it comes to redundant breathing gas, conservative is good in my opinion.
My thought is that if you sling a pony a 30 makes more sense as they sling as well or better than a 19 for relatively little additional weight and a 30 or 40 will retain some usefulness as a deco bottle if you go the technical route later on.
An SPG is also an area where there may be some disagreement. A regular SPG must be used on a back mounted pony if you want to use one whereas you can use an SPG on a 6" or 7" hose with a slung pony. Or you can use a button gauge, or you can choose to use no SPG at all on the pony.
Personally, my thoughts are that if it is a redundant emergency air source, the SPG is not needed as if you are using the pony you should, by definition, be on your way to the surface and an SPG reading would make no difference - you either have enough gas for the ascent or you don't. So my thought is to check the pressure pre-dive, either with a pressure gauge or with a button gauge on the first stage and then forget about it.
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