Spare air/pony bottle---should I get one?

[uncfnp]

I've only been diving 28 years but am in the same camp. I push my limits often but have never come close to running out of air because I tend to watch my spg often enough to never be surprised at what it reads.

So going with this same logic of monitoring SPG to never run out of air, you advocate that solo divers should not carry redundancies?

Topicstarter is not a solo diver, there is no spare air or pony bottle required by ops.

If you monitor your spg there would probably be no problem. If you really get out of air you can use an air source of a buddy.

No the op is not diving pure solo but he is talking about diving self-reliant and that means not looking to a buddy to solve issues at depth. Of course this means more then just carrying redundant gas.

I do not understand divers that argue against increasing any diver's self reliance, especially any diver without a dedicated and reliable buddy. And advice to such individuals to just get a buddy and not travel as a single diver is just nonsense.

There is no solution that works all the time, a pony bottle or spare air can fail...

So since a redundancy can also fail, be it a spare air, pony bottle or buddy, you recommend not using any redundancy?

 

[doctormike]

There is no solution that works all the time, a pony bottle or spare air can fail...

Yes, but one of the things I learned in tech training is that you don't plan for multiple gear failures, otherwise you would never get in the water. In this case, it would be simultaneous catastrophic gas loss (not OOG because of not watching your SPG), AND failure of your redundant gas supply.

 

[barth]

Yes, but one of the things I learned in tech training is that you don't plan for multiple gear failures, otherwise you would never get in the water. In this case, it would be simultaneous catastrophic gas loss (not OOG because of not watching your SPG), AND failure of your redundant gas supply.

If you just plan for one failure there are two options for me.

- If you are a solo diver you need a independent airsource.

- If you are diving with a buddy you need a good gas planning, monitor your spg, stay together etc. This is the responsibility of both divers. There is no ponybottle or spare air required.

During tech diving I plan for multiple failures. But it should make sense. I just use one bottomtimer for a cave dive I do not carry a backup bottomtimer . But I carry one primary light and two backup lights....

Everybody has to make his own choices. But I don't believe that adding more equipment does always increase safety.

I also don't believe that adding more equipment is always the best solution.

That is what people are telling here...

 

[doctormike]

If you just plan for one failure there are two options for me.

- If you are a solo diver you need a independent airsource.

- If you are diving with a buddy you need a good gas planning, monitor your spg, stay together etc. This is the responsibility of both divers. There is no ponybottle or spare air required.

During tech diving I plan for multiple failures. But it should make sense. I just use one bottomtimer for a cave dive I do not carry a backup bottomtimer . But I carry one primary light and two backup lights....

Everybody has to make his own choices. But I don't believe that adding more equipment does always increase safety.

That is what people are telling here...

Yeah, three is two, two is one, one is none... and carrying a second backup light is a pretty standard backup of a backup. But other than that, planning for multiple failures makes it very difficult to mitigate the wide range of possibilities.

I have enough back gas to finish my ascent safely if I lose a deco bottle. But if I have to start planning for lost gas AND lost backgas, I won't get in the water.

So getting back to the main point, I was just saying that the fact that a pony bottle can fail doesn't mean that it's not worth carrying in some circumstances.

 

[barth]

So going with this same logic of monitoring SPG to never run out of air, you advocate that solo divers should not carry redundancies?

No the op is not diving pure solo but he is talking about diving self-reliant and that means not looking to a buddy to solve issues at depth. Of course this means more then just carrying redundant gas.

I do not understand divers that argue against increasing any diver's self reliance, especially any diver without a dedicated and reliable buddy. And advice to such individuals to just get a buddy and not travel as a single diver is just nonsense.
So since a redundancy can also fail, be it a spare air, pony bottle or buddy, you recommend not using any redundancy?

If you are a solo diver it would be a good idea to carry a pony bottle.

You are diving solo or a be good buddy. There is nothing between it for me. I will always help my buddy if I should help him or her. If my buddy don't watch me or if I don't like my buddy I will thumb the dive.

I don't understand that people are diving with buddy's they don't like and/or don't trust. Why are that people not finding better buddy's or doing solo diving ?

There is always redundancy for me. But I never carry a spare air/ponybottle when I am diving with a buddy.

But I don't think it's true that a buddy is most of the time reliable and a ponybottle is always reliable. (Because of that I was telling that a ponybottle can also fail.)

 

[Aanderson81]

If you are a solo diver it would be a good idea to carry a pony bottle.

You are diving solo or a be good buddy. There is nothing between it for me. I will always help my buddy if I should help him or her. If my buddy don't watch me or if I don't like my buddy I will thumb the dive.

I don't understand that people are diving with buddy's they don't like and/or don't trust. Why are that people not finding better buddy's or doing solo diving ?

There is always redundancy for me. But I never carry a spare air/ponybottle when I am diving with a buddy.

Being that I dont have kids I tend to travel on off peak US travel weeks. This seems to mean I am less likely to dive with English speaking travelers. My last vacation I was on boats that spoke almost exclusively spanish and German. It's not that I didn't think they were capable divers but literally I was part of my own briefing and paired off with someone I couldn't communicate with before the dive. This is why when diving on vacation I'd rather be self reliant as best as I can be. Spare air provides an extra layer of protection when redundancies aren't needed. And they are small enough and easy enough to travel with much easier and more likely to be used. This is my point to them. I agree the price is a bit high but the used market seems to be much better on them than the MSRP indicates

 

[MaxBottomtime]

So going with this same logic of monitoring SPG to never run out of air, you advocate that solo divers should not carry redundancies?

I don't advocate to other divers at all. I make decisions for myself. I chose to only take what I need on the dive. The only thing I do differently during a solo dive is not worry about where my buddy is. Other than that, I make the same dive, watch my spg and begin my ascent with more than enough air to complete the dive.
When I make a tech dive I carry multiple tanks as I can't make a nonstop ascent. For recreational dives I can ascend any time during the dive as necessary.

 

[uncfnp]

If you are a solo diver it would be a good idea to carry a pony bottle.

You are diving solo or a be good buddy. There is nothing between it for me. I will always help my buddy if I should help him or her. If my buddy don't watch me or if I don't like my buddy I will thumb the dive.

I don't understand that people are diving with buddy's they don't like and/or don't trust. Why are that people not finding better buddy's or doing solo diving ?

There is always redundancy for me. But I never carry a spare air/ponybottle when I am diving with a buddy.

But I don't think it's true that a buddy is most of the time reliable and a ponybottle is always reliable. (Because of that I was telling that a ponybottle can also fail.)

Let me try a different approach since I think you are very sincere and it just a difference in perspective that separates our opinions.

The op is a diver that travels without a buddy. So at this point in his diving career a reliable buddy is not an option. So in your view that would mean solo diving, and that would mean a pony. But the op is not really trained for solo nor does he have the recommended experience. And beyond these obstacles some dive ops do not allow solo and others require a c- card, not an option at present. So that leaves self-reliant as the only viable option. And for many of us that means reduant gas.

I agree that if you agree to be buddies with someone, be a buddy and discuss expectations. It could be, as in my only experience with instabuddies, we both agree to mutual self reliance but still keep on eye out for the other. Other times its the even less ideal, but frequently use, option to using the guide as the DM and there are several recent threads addressing the problems with this approach.

So in the ideal black and white world dedicated buddy or solo rules but in the real world there is too much grey not to take steps to be self reliant.

 

[doctormike]

I think this bears repeating, since some of the responses from very experienced divers seem to be missing the point.

A redundant gas supply is for one thing - catastrophic gas loss. This can be due to a free flowing regulator, a burst LP hose, etc... It is NOT for running OOG due to inattention. If that is the problem, you can't fix it with a piece of gear. So all the statements about watching your SPG are irrelevant in this discussion.

Therefore, AFIK, the two agencies that certify divers as self reliant (SDI and PADI) both require a redundant gas source. If you choose to solo dive without a redundant gas source, you may be fine in the event of catastrophic gas loss assuming that you have your wits about you to CESA immediately. I personally solo dive with a redundant gas source.

 

[JohnN]

I've got a 30 cf pony with a Sherwood SR1 reg. I've dove in a local quarry a few times. It's got a stage kit on it, which uses 2 bolt snaps to clip it to D-rings on my left side BCD.

I've got a 3 cf Spare Air I've used to multiple dives by the Channel Islands in California on a trip.

Some thoughts:

1.) Spare Air is way lighter.
2.) Included 'holster' hugs to S.A. to me higher; the pony hangs fairly far off/down.
3.) With the pony, the hose between 1st & 2nd stage on the SR1 sticks out. Efforts to secure it to the tank side with the rubber band? Not very effective. A nuisance. Non-issue with Spare Air.
4.) The top/regulator on S.A. screws off pretty easily.
5.) When I get to a destination, I can fill the S.A. from a tank. Don't need the op. to do it, so the op. probably won't cut me off by refusing unless I let them do a visual inspection since the valve's been off.
6.) Takes me 40 something breaths to empty it at the surface.
7.) Not every destination provider rents ponies.

I've seen a couple write-ups where somebody basically decided to 'drill' an OOA emergency at 90 feet, ascend properly, do a safety stop, etc..., with a S.A. and basically it didn't get'ed all the way up. But there's value in a controlled slow ascent and at least partial safety stop before heading up.

At 90 feet if your 2nd stage falls off the hose, or your setup otherwise quits giving air, do you 40 something surface equivalent breaths (close to 4 atm, let's stay 12 maybe?), or none?

A Spare Air 3 cf (I wouldn't mess with smaller) is not about a rule of thirds approach to let you retrace your path to the start, ascend properly, do a 3 minute 15 foot safety stop & all from the point of maximum planned dive plan distance.

A Spare Air is about letting you stop, consider what's going on, then ascend at a more controlled rate. Perhaps even take a moment to snap a strand of entangling kelp?

The convenience factor in traveling & using a big, even if that's not obvious. I don't think of S.A. so much as something people use instead of a pony, as rather something people who'd have skipped the pony due to hassle factor, and thanks to S.A. maybe don't dive with no redundancy.

Spare Air 3cf is good for what it is, and if that's what you're after and plan for, it can be good for you.

Oh, I have run across reviews of S.A.'s losing pressure over time. Hasn't been an issue with mine, but I suggest the optional button pressure gauge where you can see how much pressure is left in it.

Richard.

Good luck with any sort of reasonable ascent from 100' with a spare air.

Let's say you take a whole 30 seconds to figure out that poo has hit the fan (and assume with everything going on, you can keep your SAC @ 1.0 ft^3)

30 seconds of gas:
(0.5*1.0*4) = 2.0 ft^3 (oops you're 2/3 there and now at 1000 psi)

Let's be generous and say that first stage can deliver down to a tank pressure of 150 psi, so you have 850 psi remaining, that leaves you (850/3000)*3 = .85 ft^3 of gas

Let's be generous (again) and say you pull your SAC down to a more reasonable 0.5 ft^3/min and ascend at 60 ft/min


@ 90 ft .23 ft^3 of gas consumed
@ 80 ft .45 ft^3 of gas consumed
@ 70 ft .64 ft^3 of gas consumed
@ 60 ft .81 ft^3 of gas consumed

and now you're OOA (again). Really doesn't sound like fun

A 19 ft^3 pony is easy to travel with, weighs almost nothing under water and give you ample time to make a leisurely (30 ft/min) ascent from 100' with time for a safety stop