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how deep max. when diving solo?

Discussion in 'Solo Divers' started by Taliena, May 5, 2014.

  1. Bigd2722

    Bigd2722 Solo Diver

    # of Dives: 500 - 999
    Location: Winter Park, fl
    458
    90
    28
    Pretty much agree with all of this
     
  2. BFRedrocks

    BFRedrocks Solo Diver

    # of Dives: 200 - 499
    Location: Phoenix, AZ
    402
    108
    43
    Since being officially certified last fall as a solo diver, I've done solo dives to a max depth of 75 ft. For myself (diving with a 19cu ft pony FWIW), I start feeling somewhat "uncomfortable" by myself at depths greater than 70 ft, so I would say my solo "limit" would be 75-80 ft. With that said, when I originally told my wife I would be solo diving, I said I wouldn't go any deeper than 35-40 ft. Well, that changed on solo dive #2. :) Seriously though, dive to your comfort (and safe) level, but as folks already alluded, solo should be fun and relaxing.
     
  3. TMHeimer

    TMHeimer Divemaster

    # of Dives: 500 - 999
    Location: Dartmouth,NS,Canada(Eastern Passage-Atlantic)
    12,116
    2,612
    113
    I've been to 120' solo with pony once (mainly because a local Instructor in Flaorida agreed to be my buddy (not a class), and he disappeared on me). Other occasions have seen me at 50' or so, either by design, or because a buddy decided to abort. My general rule is no deeper than 30 (I will wander down more if there is a chance of shell collecting)'--CESA doable-basically snorkeling with a tank.
     
  4. markmud

    markmud Self Reliant Diver--On All Dives. ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: South Lebanon, Ohio
    1,136
    1,069
    113
    Hello All,

    I would like to revise and extend my previous comments due to evolving circumstances.

    I now feel comfortable diving to 110 feet while solo diving. I normally use 32% EANx (MOD 110'). I have made quite a few solo dives between 80 and 110 feet. The diving conditions were 55 degrees and warmer, no overheads, no deco, no current, no surge, 75+ foot visibility, and practically no foreseen situation where entanglement could occur.

    I dove with my 100 cf PST E7 100 and a 6 cf pony that is tank mounted (a rec rig; not hogarthian).

    I have performed practice pony bottle ascents from 105' with either a 6 cf pony or a 13 cf pony. I always double down on the practice ascent with two issues, like a lost mask, or a loss of buoyancy, or a entanglement scenario. I shoot my SMB. I have never run out of gas with either pony bottle (I always make manual BCD adjustments).

    I will sling my 13 cf pony if diving deeper than 110 feet or if conditions are not pristine.

    My question to those who went down the rabbit trail on this thread and recommended huge volumes of back-up gas and/or criticized the use of a 6 cf or a 13 cf pony:
    1. why are you panicking while in a OOA scenario?
    2. Why is a person who has at least 100 logged dives (see Note) running out of gas at 100 or 130 feet?
    3. If you are within NDL, why do you need a safety stop when you are involved in a minor emergency? Safety stops are optional.
    4. Why does a trained and experienced diver have a SAC greater than 1 cf per minute. If it is you, you need to cross train and get your lungs in shape.
    Note: 100 logged dives is a prerequisite for obtaining a solo/independent/self-reliant cert.

    Theoretically, and my experience proves that I can do a direct ascent to the surface while dealing with a failed primary breathing system, a buoyancy issue, or a lost mask, or a faked entanglement, or a failed computer, and I shot my SMB on 4.25 to 5.5 cf of gas. Once, I did three practice ascents on my 13 cf without refilling it.

    If you are correct, what am I doing wrong?

    Solo tec diving is a completely different issue that is beyond my training level.

    markm
     
    Last edited: Feb 21, 2016
  5. Basking Ridge Diver

    Basking Ridge Diver Solo Diver

    # of Dives: 200 - 499
    Location: New Jersey
    1,898
    922
    113
    You are not asking me directly because I agree with your assessment...

    So - You are not doing anything wrong. It is well within my risk assessment to agree with your calculations... But I bought a 19 cu foot pony and that is the one that is most comfortable for me. I feel very confident that my 19 cu ft is the correct emergency redundancy for me. :)
     
    markmud likes this.
  6. lamarpaulski

    lamarpaulski Solo Diver

    # of Dives: 500 - 999
    Location: Calif.
    747
    246
    43
    About 100 max..never deco...usually hang out pretty shallow but sometimes a Giant Sea Bass will lure me to 100 ish.
     
  7. Kevrumbo

    Kevrumbo Banned

    # of Dives: 1,000 - 2,499
    Location: South Santa Monica Bay/Los Angeles California, USA
    5,659
    1,345
    113
    Because you need some extra margin of gas in a larger pony for any ascent starting beyond 30 meters, especially worst case scenario in conditions of extreme physical exertion like fighting a current --CO2 retention is the danger and the sudden narcosis that can occur:

    Carbon dioxide acts as a respiratory stimulant and can cause depression of the central nervous system (CNS). The effect depends on the level of carbon dioxide in the blood. Deep diving produces elevated blood carbon dioxide levels for several reasons, which include:
    1. the resistance to breathing caused by breathing denser gas [especially Deep Air] through a regulator and against a higher ambient pressure;
    2. reduced ventilation efficiency due to the denser breathing gas; and
    3. reduced transport, and, hence, elimination of carbon dioxide.
    Hypercapnia increases narcosis and the likelihood of CNS oxygen toxicity. In addition, it may increase heat loss, alter heart rhythm and predispose to decompression illness. If the carbon dioxide level gets too high, and it can on deep scuba dives -- especially if a diver is very anxious and / or exerting him/herself -- the diver may go unconscious without warning. Certain divers are more susceptible to severe hypercapnia for a variety of reasons and are therefore more at risk.

    CO2 Retention/Hypercapnia and Narcosis: Deep Air with increased Gas Density & Work-of-Breathing Dyspnea; then throw in Physical Exertion or a Stress Condition, resulting in overbreathing the regulator --all leading to the Vicious Cycle of CO2 Retention and sudden Narcosis (also known as the panicky feeling "Dark Narc"). Can result in severe cognitive impairment at depth or worst case stupor and ultimately unconsciousness. . . In order to break this CO2 build-up cycle, you have to relax with a few minutes of full slow controlled inspiration breathing [the point is a 6cf or 13cf pony will not provide this margin at all from 30m]: --cease & desist all physical exertion that stimulates hyperventilation and abort the dive if indicated.
     
    Last edited: Feb 21, 2016
  8. BCSGratefulDiver

    BCSGratefulDiver Mental toss flycoon ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: On the Fun Side of Trump's Wall
    73,154
    57,152
    113
    I suspect that what you're doing wrong is overestimating your own abilities ... it's a common problem among scuba divers.

    Regardless of how many "issues" you're practicing with ... and I applaud the fact that you are practicing, so don't take this the wrong way ... it's an artificial environment. You're planning those failures in advance of the exercise, and practicing under essentially ideal conditions. The real world may not be so kind. In unforeseen circumstances ... or even something stressful such as current (particularly a downcurrent) or an unexpected big animal encounter, I've seen people's consumption rate shoot through the roof ... double of normal is about average, and I've seen them go much higher than that.

    Now you might be some kind of phenom who doesn't breathe much, and who maintains his calm no matter what's going on, in which case the conditions you describe may well apply to you. My experience with lots of diving, lots of divers, and lots of different circumstances would tell me that's not typical among divers, and that prudence would dictate not cutting your margins that close for the sake of some minimalist approach to diving.

    Or not ... the risk is yours to take, and you're welcome to make that choice. I don't think it's a good idea to advise other divers to emulate your strategy, though ... to my concern, you're cutting your margins way too thin.

    ... Bob (Grateful Diver)
     
    LeadTurn_SD likes this.
  9. uncfnp

    uncfnp Solo Diver

    # of Dives: 500 - 999
    Location: North Carolina
    5,837
    4,036
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    1) What does panicking have to do with a larger tank?
    2) A pony is not just for "running out of gas" It is for unplanned emergencies. And I agree that running out of gas because of carelessness should not be one of them.
    3) You and I both know that NDL is not a hard and fast line. Its a great big grey zone. Even if just close to that zone, I want a safety stop.
    4) In an unplanned event, I guarantee your baseline sac will go up. Its the experienced diver that will know this and also know to get that breathing rate back into control asap.

    FWIW I dive a 13 cf but if I had a do over I would get a 19. Not because I need that much to make a safe ascent but because it give a diver a higher margin for gas loss or a less than full tank.

    Then again, the 13 is perfect for travel so looks like I may just buy yet another tank. :banghead:
     
    Last edited: Feb 21, 2016
  10. scubadada

    scubadada Diver Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Philadelphia and Boynton Beach
    10,780
    6,211
    113
    The choice of a pony has been debated many times on SB. I have been solo diving for 7-8 years, now almost exclusively solo. I have about 300 solo dives, about half deeper than 80 feet. When I chose a pony, I made the classic, conservative calculation of a minute on the bottom, a 30 foot/min ascent, a 3 min safety stop, all at twice my average SRMV. Using that calculation, I need about 17 cf for an ascent from 130 feet and dive with a 19 cf pony. Knowing I could do a direct ascent to the surface at 60 feet/min with 5 cf is reassuring, however, knowing I have a considerable safety margin is much better. It's a personal decision, the only one you need to convince that you're doing the right thing, is yourself.
     

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