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Redundant Air: H Valves, Ponies, Doubles, And The Surface.

Discussion in 'Solo Divers' started by 2airishuman, May 6, 2016.

  1. 2airishuman

    2airishuman Solo Diver

    # of Dives: 100 - 199
    Location: Greater Minnesota
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    Yesterday I dived solo in a lake that is 8 feet deep at its deepest point. It's nearby and I wanted to get wet.

    Planning my dive, I determined that immediate access to the surface during all phases of the dive obviated the need for redundancy of scuba equipment.

    I've used pony tanks and back-mounted doubles for slightly deeper solo dives, to about 25', but in reality that's as much about training and familiarization as safety. I've thought about using an H-valve setup.

    When do you believe a solo dive requires redundant air to be safe? At what thresholds do you believe that progressively more capable redundancy (H valves offering the least and doubles offering the most capable redundancy, with ponies somewhere in between by most people's reckoning) becomes necessary?
     
  2. uncfnp

    uncfnp Solo Diver

    # of Dives: 500 - 999
    Location: North Carolina
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    Depends on your definition of safe. Safest is to always have redundancy.
    Whatever depth you would prefer not making a CESA. For me that is a combination of time and depth. If anywhere near NDL, nothing over 20 feet. If I know I will not approach NDL, about 40 feet. For me its not just the emergency ascent but no option for the safety stop.
     
    Last edited: May 6, 2016
    LeadTurn_SD, KWS and exposure like this.
  3. 2airishuman

    2airishuman Solo Diver

    # of Dives: 100 - 199
    Location: Greater Minnesota
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    For the sake of this discussion, let me suggest this alternative phrasing of what I see as the same question: "When do you believe a solo dive cannot be made materially safer by having redundant air available?"

    I disagree. I believe there are dives where redundancy provides no benefit. There are also dives where redundancy provides a negligible benefit.
     
  4. Basking Ridge Diver

    Basking Ridge Diver Solo Diver

    # of Dives: 200 - 499
    Location: New Jersey
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    I have done drift dives off West Palm Beach to 90 feet on a single tank on vacation - effectively in my opinion it was a Solo dive. I was not diving with a buddy and the closest person unless we bunched up to see a Sea Turtle was not close enough in an OOA condition.

    When I intentionally go Solo diving close to home - 30 feet is where I prefer to bring my pony. Anything less than 30 feet I believe is an acceptable risk for me.

    So - I dont know how to answer your question - but I would draw my own line based on my experience and my comfort level. Not sure someone else's decisions should reflect your own line. :)
     
  5. rx7diver

    rx7diver Solo Diver

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    2airishuman,

    How is the visibility in the lake? Can you easily see that you're not swimming into/under/through/near something? Is there significant potentially hazardous stuff (like fishing line) in the lake? Is there anything (like overhead boat traffic) that might prevent you from surfacing immediately if you might need to?

    Eight feet is shallower than the deep end of many (most?) public swimming pools. How comfortable are you swimming in and going beneath the surface of a public swimming pool?

    Safe Diving,

    rx7diver
     
    shoredivr likes this.
  6. uncfnp

    uncfnp Solo Diver

    # of Dives: 500 - 999
    Location: North Carolina
    5,838
    4,040
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    I disagree. :wink: Not everyone reacts the same in an emergency and anyone, even the best among us, can panic and it only takes a teaspoon of water to drown. I believe the emotional as well as the actual physical presence of redundancy can offset some of this risk. And of course there is the dive condition factor suggested by rx7diver. Entrapment? I agree the odds are long for both occuring simultaneously but I was speaking hypothetically.

    I should also add that I am speaking of divers in gear configurations they are familar with and comfortable using.
     
    Last edited: May 6, 2016
  7. 2airishuman

    2airishuman Solo Diver

    # of Dives: 100 - 199
    Location: Greater Minnesota
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    I was trying to start a general, abstract discussion, not one about the specifics of my local lakes or my skills.
     
  8. exposure

    exposure Tech Instructor

    # of Dives: 2,500 - 4,999
    Location: Paris, France
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    By the way, H valves do not provide redundancy. It just give you the possibility to have two first stages but juste one tank. That is not a solo diving configuration at all.

    In any case, as solo diver, I am using an extra tank, either by using twinset, or sidemount or maybe an AL40 with my single tank (on H valves in France :)). No other set up for solo? even shallow, I am not a fan of CESA.
     
    letonac, Colliam7 and Jim Lapenta like this.
  9. rx7diver

    rx7diver Solo Diver

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    2airishuman,

    I actually decide whether I will do a particular dive solo—and how—using all of what I wrote. (And other criteria as well.) The most enjoyably, effortless solo dives (for me) are the ones I dive without redundancy—which is nearly every dive I do these days. These dives are each not too deep (though usually a bit deeper than 8 ffw), in pretty benign environments, with reasonably good visibility. If the water is very cold, I will use a Y-valve (one post for my drysuit, and the other for my BC), but other than that, cold (for me) doesn't in itself mean I will necessarily take a redundant air supply.

    At this time I am experimenting with deleting the BC from my solo diving kit, as well. The old-school mindset, where a scuba diver was a breath-hold diver first, but used his/her "aqualung" simply to "extend" what would be a breath-hold dive, provides a lot of insight with respect to choice of exposure wear, proper weighting, technique, etc.

    Safe Diving,

    rx7diver
     
    Last edited: May 6, 2016
  10. Bob DBF

    Bob DBF Solo Diver

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    Location: NorCal
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    First you would have to decide if you believe that the surface is redundant air, it certainly is plenty of air. At 8' away it is probably closer than most buddys.

    As for when a solo diver should carry redundant air, it is up to the diver. I do not have a hard and fast depth, it is purely dependent upon my dive plan. The more involved and task loaded the dive is, the more likely I will sling a pony. The only doubles I own are a couple of sets of old J-valve double 72's so I don't get a lot of redundancy using them, unless I decide to plumb them for independent doubles.

    I would say that if you are a solo diver because you took a course, then you better follow the book, as you will not have the experience of diving solo for years or decades to draw upon. If you have been diving solo for decades then you should already have your own rules.



    Bob
     
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