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Deep Diving 108 feet w/ a single AL 80 (Air.) No redundancy.

Discussion in 'Advanced Scuba Discussions' started by Boston Breakwater, Oct 16, 2020.

  1. Boston Breakwater

    Boston Breakwater "Outlaw." Solo Diver ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Brunswick, Georgia.
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    Hello. I was thinking back over the years. I worked for a Dive shop years ago as a Divemaster.
    We did our deep dives on the Chester Poling off Gloucester, Mass. for the P.A.D.I. Advanced Open Water Course.
    At high tide the the wreck sits in 108fsw. It always amazed me that people would do this dive "Normally." on single aluminum 80's without any type of redundancy.
    I always thought it was insane???? Divers would come back on board with extremely low pressure readings on their gauges. Too me, it left no room for error, or any type of contingency whatsoever. At that time, I was diving with an Aluminum 100 cubic 3300 P.S.I. (Air.) with a 30 cubic pony bottle.(Air.)
    20 years ago the shop did not have "Nitrox." (This is not an enriched air scenario.)
    Staying within N.D.L.......I don't care how long you've been diving, or if, your'e the best breather on the planet your max bottom time is approximately 18 to 20 minutes, at 100fsw, not including the 3 min Safety stop.
    So, I was curious? The question is: Would you personally make this dive, staying within N.D.L. on air........No redundancy?
    Cheers.
     
    rjack321 likes this.
  2. bakodiver391

    bakodiver391 DIR Practitioner

    # of Dives: 2,500 - 4,999
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    No, I would choose a steel 108 or 130 with H valves, and if I was responsible for others, an AL40 pony.
     
  3. Akimbo

    Akimbo Lift to Freedom Volunteer Staff Member ScubaBoard Supporter

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    I have used a single deeper than that most of my life, but I practice free ascents from my max no-redundancy depth every year or so. I was also trained to do them in my first Scuba course and in the Navy. It is even easier since I took the PFI Intermediate Freediving Course about 10 years ago.
     
    eleniel, captain, Bob DBF and 7 others like this.
  4. tursiops

    tursiops Marine Scientist and Master Instructor ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
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    Then and now, leading or being led, there is no reason to go to NDL at that depth. Five minutes on the bottom is plenty to do the AOW deep dive -- which has 100 ft max, so 108 would be breaking standards -- and still get to the surface with a decent reserve. One of the things to learn on the AOW deep dive is that the deeper dives are run on air usage and NDL, not just one or the other.
     
    Jay Adams likes this.
  5. MaxBottomtime

    MaxBottomtime Divemaster

    # of Dives: 2,500 - 4,999
    Location: Torrance, CA
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    I have done similar dives dozens of times. These days, I prefer to limit my depth to the cubic feet of the tank(s) I'm carrying plus 10%. I would not go below 88 feet with a single 80.
     
  6. NorCalDM

    NorCalDM Barracuda

    # of Dives: 500 - 999
    Location: Vacaville California
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    I have dove to this depth many times on a single cylinder with no pony. Everybody has a different view of risk and I think for some a pony is a false since of security.
     
  7. broncobowsher

    broncobowsher Solo Diver

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    Guide in Truk was down at 190+' on an AL80 of air with a second slung. Does it every day, over 10,000 dives.
     
    TONY CHANEY likes this.
  8. BurhanMuntasser

    BurhanMuntasser Dive Charter

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    I have done the Chester Poling so many times, I don't remember them all. I caught my biggest lobster on the Chester Poling, 20lbs circa 2000. Most of the time single tank no pony (120cuft tanks with nitrox).
     
    Jay Adams and Sam Miller III like this.
  9. Barnaby'sDad

    Barnaby'sDad ScubaBoard Supporter ScubaBoard Supporter

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    No. I did such a dive in that area with an AL100 and every other diver on the boat was running AL80’s (all rental tanks). The DM was carrying a pony bottle. AL30 or 40, IIRC. That’s not a lot of spare gas if more than one of the divers runs into an issue.

    People are welcome to do that if they’re comfortable with it. I’ll be using a HP100+ from now on. It’s not that I think it’s dangerous (I’m sure plenty of people do it without giving it a second thought), it’s that at that depth and with my gas consumption...it wouldn’t be worth my time (my two cents) to do a ~100’ dive with an AL80.
     
    Boston Breakwater likes this.
  10. Angelo Farina

    Angelo Farina Marine Scientist

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    In the last 30 years I did never dive deeper than 35m.
    I always used a 15 liters filled at 210-230 bars, with double valve and two completely independent regs.
    I would not use anything with less capacity even for much shallower dive.
    If going inside a cavern or a wreck, or planning to exceed slightly the NDL, I would add a 3-liters pony, with a third reg.
     
    Yawana-Dive likes this.

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