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Why extra air when solo?

Discussion in 'Solo Divers' started by pauldw, Jul 11, 2019.

  1. pauldw

    pauldw Solo Diver

    I gather that for people taking a solo course, the official equipment standard is to have a pony bottle or some such thing. My question is: why? And it's a serious question, I really don't get it.

    My own experience a long time ago when I first certified inland and then went home to the NW coast on break from school and wanted to see the subtidal instead of just the intertidal was that if I wanted to see it, I'd best go when the going was good and that meant going on my own. Off a nice sloping rock shelf into nearly flat water on an unusually clear day, one of the days that are very few and far between there. I don't know where I'd have found a buddy. Since I was around 10 to 20 feet, maybe 30 feet deep tops, I figured that if I got into trouble at 10 to 20 feet, I could blow and go quicker than I could either try to find and get to a buddy if I had one, or fix the problem where I was. Now that I'm getting back into diving regularly, and my favorite place to travel to will be those same remote rocky shores, I thought about formally training in solo, but I'm not enthused about having to buy more big and heavy gear. So, why do I need a pony bottle when diving at 10-30 feet? Specifically, if my regulator fails, I have a second. If that fails too, then that would be sad. But how likely is that in real life? If both of them weren't getting air, that would probably mean my first stage had to have failed (unless, I suppose, I was stupid enough to run out of air). Are first stages prone to failure?

    Is the whole logic behind the extra air source that someone might run out of air in their cylinder, or is there some other reason?
  2. Mike1967

    Mike1967 Manta Ray

    # of Dives: 100 - 199
    Location: Victoria, Australia
  3. KenGordon

    KenGordon Rebreather Pilot

    The idea is not so much more gas as a separate supply in case the first one becomes unavailable.

    In cold conditions a freeflow is a likely event. If you are at all deep and on your own that is a proper problem. A freeflow is just one example, other failures are possible and you don’t want it to be a death sentence.
    jridg, NothingClever, Bagoose and 4 others like this.
  4. Miyaru

    Miyaru Tech Instructor

    # of Dives: 2,500 - 4,999
    Location: EU
    I can follow your logic, but you'll have to change that point of view. And that is: plan for the most unlikely situation.

    During a week of deep wreckdiving, we had 1 extra team stage with nitrox. Just in case. That tank went down with the team on every dive, and was eventually taken home again, unused. And not using/needing it was the plan.
    Look at cave divers. They usually come out of the cave with more than their planned reserve. You never bring too much gas.

    Diving solo means no buddy who has an independent gas supply. So you bring your own. Separate tank, first stage and second stage. Which you will not need in your planning. Just in case the sh#t hits the fan.
    jridg, BlueTrin, markmud and 7 others like this.
  5. scubadada

    scubadada Diver Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Philadelphia and Boynton Beach
    At 10-30 feet, the necessity of redundant gas is tenuous. You are not likely to run out of gas acutely due to equipment malfunction. Unless you are entangled, you can do an ascent.
    markmud, BlueTrin, Wingy and 5 others like this.
  6. MichaelMc

    MichaelMc Divemaster Candidate

    # of Dives: 100 - 199
    Location: Berkeley, CA
    About the one thing you have to have is air. Mechanical things fail, the environment intrudes, and users make mistakes.

    If your air fails, you have a half to two or maybe three minutes to fix that. Or die.

    In fixing that by ascending, you may cause or run into another issue, entanglement in kelp, reg or gear stuck in some crack in the rock, boats, panic, embolism from breath hold ascent, or DCS from rapid ascent. The first few mean you'll die if you don't fix it and ascend in that short time. If you embolize with no surface support, you have a good shot of dying. DCS from this incident will make a bad week or years.

    Yes, at 20' in clear water over a sand bottom, getting to the surface is fairly straight forward. Beyond that range you start rolling the dice. In solo, you've removed some safety net of a good buddy. It's best to hedge the bets as best you can.

    Separate air systems is a good hedge on breathing. You don't have to go anywhere to keep breathing. You just need to deploy it. I dive sidemount and switch regs during every dive, or tiny doubles where my backup is under my chin. It also makes conversations with loved ones or new divers simpler. There are procedures for solo, and you are following them.

    One is none. Two is one. (When the first one somehow fails).

    ETA: It is separate air to call the dive. Which does also means it's an extra amount of air, unless you also shorten your dives.
    jridg, BlueTrin, markmud and 3 others like this.
  7. rhwestfall

    rhwestfall Solo Diver

    # of Dives: 200 - 499
    Location: "La Grande Ile"
    I'll add to the list: Artificial Overhead (boats!)
  8. rhwestfall

    rhwestfall Solo Diver

    # of Dives: 200 - 499
    Location: "La Grande Ile"
    Why do you carry two cutting devices?
    Dark Wolf and dead dog like this.
  9. scubadada

    scubadada Diver Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Philadelphia and Boynton Beach
    The right one for the job
  10. 1isNone

    1isNone Solo Diver

    # of Dives: 0 - 24
    Location: 12' above the fun stuff
    One is none and two is one.

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