Why extra air when solo?

[Zef]

Ok, I’ll bite. What’s the point of solo diving with a fully redundant gas supply and then putting two second stages on your back gas?

I understand your statements and question to be from the standpoint that if you are diving Solo, then there is no reason to have a "safe second"/backup 2nd stage to donate to a partner because the partner does not exist.

Here are my thoughts on my configuration:
I dive with a pony bottle that is significantly smaller than my back gas. If my primary 2nd stage becomes problematic/fails I can switch to my backup 2nd stage and continue my dive using my back gas, the pony bottle remains my contingency reserve. If I did not have the backup 2nd stage installed it would be necessary to switch to the pony tank and abort the dive.

The viable argument would be that if one suffers an equipment casualty when diving Solo, they should always abort the dive. I believe that If you have enough of the proper equipment on hand during the dive to still maintain the necessary redundancy then there is no need to abort unless that is what is planned or otherwise desired....but this is Solo diving, so that would be entirely a personal decision from the outset.

-Z

 

[doctormike]

I understand your statements and question to be from the standpoint that if you are diving Solo, then there is no reason to have a "safe second"/backup 2nd stage to donate to a partner because the partner does not exist.

Here are my thoughts on my configuration:
I dive with a pony bottle that is significantly smaller than my back gas. If my primary 2nd stage becomes problematic/fails I can switch to my backup 2nd stage and continue my dive using my back gas, the pony bottle remains my contingency reserve. If I did not have the backup 2nd stage installed it would be necessary to switch to the pony tank and abort the dive.

The viable argument would be that if one suffers an equipment casualty when diving Solo, they should always abort the dive. I believe that If you have enough of the proper equipment on hand during the dive to still maintain the necessary redundancy then there is no need to abort unless that is what is planned or otherwise desired....but this is Solo diving, so that would be entirely a personal decision from the outset.

-Z

OK, fair enough. As a solo diver, you bring a backup second stage so that you can continue to dive on your back gas in the specific case of your primary second stage failing closed.

That's a very unusual situation, and to me it's not worth adding the failure point just so that I could continue to dive (instead of ascending) if that happened. Far more common situations would be LP hose failure or an unrecoverable free flow, in which case the backup second stage on your back gas is not useful - you need to go to your alternate gas supply and ascend.

 

[AfterDark]

Yeah, I guess if you are switching back and forth a lot, you might not feel like taking it off. To me, the 30 seconds it takes to remove or replace the octo is worth eliminating a common failure point and streamlining the reg. Given what it takes to assemble, disassemble and clean gear for a diving day, it seems like it would be worth it. But of course, I see your point.

However, my response was really to the OP, who wasn't talking about that, but rather an analysis of what he would do in a failure situation. To my reading, he was implying that having a backup second stage would address the gas loss issue as well as a redundant gas supply, which is not correct. He said:

Doc I've got to say that, in all my years of diving I've never had any of my regulators fail to the point of being unusable. Occasionally I might get a slight free flow that doesn't even affect the breathing, just the gas consumption. Early in my dive experience I would dive solo on working dives I'd pick up during the summer, sans redundant air or even an octo; octos weren't popular, yet. Reliability is one of the reasons I've stuck with the some brand and model regulator for the past 50+ years. I now have 4 of the same thanks to Ebay and Vintage Double Hose. I've given thought to a dedicated buddy diving reg and 2 solo regs for my ID's but one of my PDCs is mounted in my console so if I wish to keep redundancy with my PDCs I'd have to transfer the console back and forth between regs. Catch 22. However not being one that "trusts" in anything or body but myself, I have shut off switches on all my 2nd stages if I do ever experience a runaway free flow I'll be able to shut that 2nd stage down; and yes I have OPVs in the 1st stages.

Yesterday I was solo diving in 10FSW looking for sea horses with my old US Divers Aqua Lung Jet Air double hose reg. No octo, no redundant air no auto inflator. Just me and my lungs.

 

[doctormike]

Doc I've got to say that, in all my years of diving I've never had any of my regulators fail to the point of being unusable. Occasionally I might get a slight free flow that doesn't even affect the breathing, just the gas consumption. Early in my dive experience I would dive solo on working dives I'd pick up during the summer, sans redundant air or even an octo; octos weren't popular, yet. Reliability is one of the reasons I've stuck with the some brand and model regulator for the past 50+ years. I now have 4 of the same thanks to Ebay and Vintage Double Hose. I've given thought to a dedicated buddy diving reg and 2 solo regs for my ID's but one of my PDCs is mounted in my console so if I wish to keep redundancy with my PDCs I'd have to transfer the console back and forth between regs. Catch 22.

Yesterday I was solo diving in 10FSW looking for sea horses with my old US Divers Aqua Lung Jet Air double hose reg. No octo, no redundant air no auto inflator. Just me and my lungs.

Yup, all of this makes sense, although I would avoid stressing that point about "my regulator has never failed because I have good ones and I maintain them". It kind of leads to normalization of deviance if that becomes widely accepted, which is why I usually push back a bit here since these discussions are archived and read by a lot more people than just those who comment.

And of course, you can always point out extremely shallow depths as an exception to all diving rules, but again, it leads to people saying "well if this is OK for 10 feet, then it's OK for 11 feet, etc..."

Just my two PSI...

 

[AfterDark]

Yup, all of this makes sense, although I would avoid stressing that point about "my regulator has never failed because I have good ones and I maintain them". It kind of leads to normalization of deviance if that becomes widely accepted, which is why I usually push back a bit here since these discussions are archived and read by a lot more people than just those who comment.

And of course, you can always point out extremely shallow depths as an exception to all diving rules, but again, it leads to people saying "well if this is OK for 10 feet, then it's OK for 11 feet, etc..."

Just my two PSI...

Agree that's why staying within ones own know limits is rule number one; which is probably why I've survived all this time.

 

[doctormike]

 

[Addicted2H2O]

I'm not a solo diver. At least not yet. It will be my next certification, but not so I can conduct solo dives per say. More do because I'm a DM that helps with OW courses and if you think about it, anytime I'm diving with students, what are the chances they're going to be able to assist should I suffer a gear malfunction, OOA situation, etc.? Also, my son turns 10 in September and will get his OW shortly thereafter. Again, when it's just he and I diving together, what is the probability that he'll be able to help me during an incident? So I look at solo diving from a little different perspective than most.

Now on to why you dive redundant air supplies. Bottom line.....why dive ANY redundant gear? It's simple. Just In Case. As you can probably tell in my avatar I typically dive a full face mask. Air is integrated so should something go wrong with any part of it, the entire thing fails. So when I dive it I ALWAYS have a regular mask in one BC pocket and a spare 2nd stage fitted w/ a QD in another. Case in point: Last month in Cozumel on a shallow <30 ft dive, the o-ring between the two hemispheres of my omni-swivel failed, free-flowing air into the Caribbean. I had plenty of time to make a normal, controlled ascent and abort my dive. But because I dive redundant gear, rather than have to call my dive, I disconnected my primary hose from the swivel (QD fitting), doffed my ffm, switched to my octo and donned my regular mask. Once I'd calmed down a bit and was breathing normally again, I pulled out my backup 2nd stage and connected it to my primary hose then switched to it and stowed my octo, thus restoring me to "normal" status, meaning should anyone suffer a failure/OOA situation, I could donate to them. Was carrying a backup 2nd stage completely necessary? Maybe not. But it kept me diving normally for another 15 minutes. And more importantly it gave me additional peace of mind so I wasn't worried for the remainder of my dive.

So all in all, I guess it's really what you're comfortable with. But plan for the worst.

 

[Zef]

OK, fair enough. As a solo diver, you bring a backup second stage so that you can continue to dive on your back gas in the specific case of your primary second stage failing closed.

That's a very unusual situation, and to me it's not worth adding the failure point just so that I could continue to dive (instead of ascending) if that happened. Far more common situations would be LP hose failure or an unrecoverable free flow, in which case the backup second stage on your back gas is not useful - you need to go to your alternate gas supply and ascend.

I was not thinking of it from the sense of the 2nd stage failing closed. In cold water, I dive with single cylinder on my back with an H valve with a first stage on each post...I can shut off the post of the 2nd stage with a problem....but I was also thinking of things like damaged mouth piece, or what not.

Full disclosure: I am not solo certified and I don't solo dive in the traditional sense, but dive with the mentality towards myself that I am diving solo. I carry the pony bottle because I do not want to be reliant on my dive partner to save my arse should things go tits-up...

...that being stated, in warmer water I dive with a single cylinder on my back with a standard valve with single 1st stage attached. I probably should still dive with an H valve and 2 first stages but my wife and kids use the extra regulators....they don't dive with me in cold water so I have the gear available for the H valve.

If I have a 2nd stage free flow problem in warmer water, depending on depth and need/desire to do a safety stop, I would either switch to the octo on necklace under my chin and head skyward, or switch to the 2nds stage on my pony bottle and head skyward.

I appreciate your post as it made me think through my protocol again, and there is always occasion to reflect on this.

-Z

 

[Storker]

To me, the 30 seconds it takes to remove or replace the octo is worth eliminating a common failure point and streamlining the reg.

Serious question: how significant is the extra drag your backup causes, and how big is the failure risk?

If I were to guess, my first answer would probably be "not at all significant"

EDIT: And if you switch between solo diving and buddy diving, there's some merit in keeping your gear the same to accommodate your muscle memory about where everything is.

 

[AfterDark]

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I was unaware I was being inspirational, excuse me, didn't mean to be. Just informational was my goal.