Spare air?

[DivemasterDennis]

First I endorse everything TS and M said. Back to the original question. I do not dive with spare air; on recreational dives I dive with the tank on my back. That is either a 72 ft. steel or 80 ft aluminum in most cases. On those dives I am either teaching, or taking pictures or videos. I choose not to be cluttered with the extra gear, so plan my dives accordingly and stick to the dive plan. I have a friend who carries a 3 ft spare air all the time, because it makes him feel better. That's his deal. How long it will last depends upon depth, conditions, the diver's panic level or stress level, and other factors. For commercial, technical, or "real" search and rescue dives, a redundant source is appropriate, often necessary. But for recreational dives with properly maintained equipment, executing a proper dive plan, no need. To each their own.
DivemasterDennis

 

[RonFrank]

Thread #5000 on the subject! :mooner:

I use a 19CF pony when I want reserve gas for deep or solo situations. I believe the best backup is a good buddy. Those are not always available when on vacation hence the desire for a redundant air supply. If spare air cost under $100 I could at least understand the appeal, but it's more expensive than a real tank and regs. For the price just pickup a 13cf or 19cf tank and cheap reg and SPG. You will have plenty of air to surface from any rec depth.

 

[RonFrank]

But for recreational dives with properly maintained equipment, executing a proper dive plan, no need. To each their own.
DivemasterDennis

Throw in a reliable buddy and I agree. Those are not always available which is why I have a 19CF even if I have never needed it. I agree, to each their own...

 

[redacted]

Provide yourself with redundancy. This can be in the form of a pony bottle, Spare Air, or double tanks . . . but the one thing it has to be is ENOUGH. Read NW Grateful Diver's article on gas management, because it will give you some mathematical tools to calculate what you may need for self-rescue from a variety of depths. It's more than you think, even if you use a rapid ascent rate and don't make any stops. The one thing you want from emergency equipment is that it be easy to use and reliable -- the one thing I wouldn't want while doing an emergency ascent when out of gas is to run out a SECOND time.

ENOUGH??? Enough to make a normal ascent? Enough to complete the planned dive? Enough to live another day? Which ENOUGH you opt for makes a big difference in what you decide to carry.

I'd rather run out of gas a second time than not have that option.

 

[Invictys]

OP: I recently conducted the same research as you are currently and came to the conclusion that for the price and wider range of conditions in which it would be useful, a standard 19-40cf pony would be better.

I am leaning toward a 30cf currently because in the future I can use it as a deco bottle if I should start doing more advanced dive profiles. So my investment has more longevity (and resale value as someone else mentioned already) than Spare Air would provide.

The breakdown on costs to set up your own pony system from DivegearExpress.com is as follows if you were curious:

	13cf	19cf	30cf	40cf
Cylinder	$129	$139	$149	$159
Dir Strap kit	$43.75	$43.75	$43.75	$43.75
HOG Regulator	$263.99	$263.99	$263.99	$263.99
1.5" SPG w/ 6" hose	$76.94	$76.94	$76.94	$76.94
Total Cost	$513.68	$523.68	$533.68	$543.68

 

[NAM001]

take your consumption rate and divide it into 2.5 cu ft. at say 66 ft you are at 3atm if you are using .5 on the surface youare using 1.5 at 66 ft that is less thatn 2 minutes till you cant suck any more. hmmmm may as well get a 13-20 pony bottle for less cost. that gies you 4-6 times the gass, and that will allow a safety stop.. any air is good air but spare air at 100 ft is next to no air. do it right the first time

Good points. Approximately how long will a spare air last for diver that is none stressed?

sent via nookcolor N2A.

 

[scubadada]

Goldilocks found the Spare Air much too small, Goldilocks found the 40 cu ft tank much too large, Goldilocks foung the 19 cu ft pony just right for self rescue from recreational diving depths.

There you go,

Craig

Other than equipment failure, I actually cannot think of any reason to be low on gas.

 

[Mitchell Teeters]

If anyone has read my other posts cost is ALWAYS a factor. The 13cf gets the nod. I have a back up reg set I can convert with a short spg. I'm a gun sling manufacturer on the side so strapping and hardware are a non-issue. I would like one of these super flexible low pressure hoses in yellow to bungee to the cylinder.

I would just need to source the tank and get it Vis/hydro (unless new, but will add $45). I suspect I will be forced to do some solo diving this summer (I'll discuss that in another thread). Just so you know I never burn my tanks down so I'm just doing this for a safety backup.


ETA: Thanks invictys.

 

[DandyDon]

OP: I recently conducted the same research as you are currently and came to the conclusion that for the price and wider range of conditions in which it would be useful, a standard 19-40cf pony would be better.

I am leaning toward a 30cf currently because in the future I can use it as a deco bottle if I should start doing more advanced dive profiles. So my investment has more longevity (and resale value as someone else mentioned already) than Spare Air would provide.

The breakdown on costs to set up your own pony system from DivegearExpress.com is as follows if you were curious:

	13cf	19cf	30cf	40cf
Cylinder	$129	$139	$149	$159
Dir Strap kit	$43.75	$43.75	$43.75	$43.75
HOG Regulator	$263.99	$263.99	$263.99	$263.99
1.5" SPG w/ 6" hose	$76.94	$76.94	$76.94	$76.94
Total Cost	$513.68	$523.68	$533.68	$543.68

Yep, virtually the same price - altho you can do better on the reg & spg I think.

I think the Spare Air appeals more to the traveling diver. How long will a 3 cf SA last? About the same as an extra 100 psi in a normal tank - no nearly enough. Go for a pony...!

When I looked at sizes, knowing that I had to check the tank in luggage, hump it inside the bag around airports to hotels, board it every trip, and climb it after every dive - I looked at weights: The 13 cf is about 6# plus valve and accessories, the 19 cf about 8# plus, the 30 cf about 13#, the 40# about 16# - so I went with the 19. Glad I am not carrying a larger one around as I don't want to be discouraged in using it.

 

[Mitchell Teeters]

Don do you just empty it for air travel?

sent via nookcolor N2A.