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Off the chart on the dive tables

Discussion in 'Basic Scuba' started by Alligood, Aug 9, 2017.

  1. Alligood

    Alligood New

    4
    0
    Hi Divers, I am new to the boards. I was certified in 1993 and dove about 20 times in the few years after that pretty much giving the sport up when kids came along. My youngest daughter just got certified at 16 and I have a renewed vigor for the sport with my new dive partner. forgive me, but I never really paid much attention to dive tables back in the day. All of my dives were single tank dives and my deepest back then was 86 feet. Now I am learning and calculating my times and I think I was off the chart on my last dive of the day. Here are my dives.

    Dive 1: 30 minutes dive at a max depth of 51 feet, but most of the dive at 20 or 30 feet.
    Surface Interval: 30 minutes
    Dive 2: 30 minute dive at 60 feet with most of this dive at 60
    Surface interval: 30 minutes
    Dive 3: 30 minute dive with the majority of time at 90 feet. Safety stops at 60, 30, 15.

    Done for the day or so we thought. The instructor says hey a guy just walked in wanting Enriched Air training. Want to get it also?

    Surface Interval 2.5 hours
    Dive 4: Nitrox Dive 32% to 90 feet. Maybe 20 minutes bottom time.

    So, how does Nitrox work on the pressure tables after three regular air dives the same day? I saw no ill effects.
     
  2. _Ralph

    _Ralph Contributor

    699
    335
    Don't want to sound rude, but it sounds like you need to take the course, and not just follow along the DM/Instructor ....

    _R
     
  3. Marie13

    Marie13 Great Lakes Mermaid ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Great Lakes
    9,191
    7,860
    Do you have a dive computer? If not, get one. As far as I can tell, your average recreational diver who uses the tables is rarer than the blue-footed boobie.
     
    Dizzi Lizzi and rongoodman like this.
  4. sea_ledford

    sea_ledford Captain

    # of Dives: 2,500 - 4,999
    Location: Galveston, TX
    695
    516
    The combination of the first three dives are very aggressive, and I can't imagine a single table out there that would allow a 30 minute dive at 90' as a third dive without completely busting the tables. Especially with only 30 minute surface intervals between each. I don't have any tables handy, but I would guess you were close to deco during the SECOND dive. These would be pushing the limits on most dive computers, let alone tables.

    Safety stops at 60, 30 and 15 are not a thing. Those would be decompression stops, and bad ones at that.

    It sounds like you were doing this with an instructor, and with a 16 year old? Was this for a class? I don't even know how the instructor could de-brief, swap tanks, brief the next dive and get in the water in 30 minutes. Find another instructor.

    Not even going to touch the nitrox thing...

    -Chris
     
    JohnN likes this.
  5. rongoodman

    rongoodman ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Albany, NY
    5,371
    2,086
    Computers are cheap. Tables aren't going to give you an accurate representation of the dives you're doing, especially if you're mixing air and Nitrox dives.
     
  6. Aviyes

    Aviyes Contributor

    # of Dives: 100 - 199
    Location: Colorado
    441
    365
    Easily busted NDL, per the PADI tables, on dive 3. Dump that reckless instructor/DM ASAP. Learn/re-learn how to use the tables or better yet get a dive computer, as recommended above.
     
  7. Basking Ridge Diver

    Basking Ridge Diver Solo Diver

    # of Dives: 200 - 499
    Location: New Jersey
    1,966
    1,010
    It works the same as an Air Table if you are able to read an Air Table then you can read a Nitrox Table.

    Can you read a Table for multi dives?
     
  8. rongoodman

    rongoodman ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Albany, NY
    5,371
    2,086
    Wouldn't the Nitrox table assume previous dives to have been made using the same blend? If so, it would underestimate the tissue loading from the air dives.
     
    Basking Ridge Diver likes this.
  9. iamrushman

    iamrushman Contributor

    # of Dives: 1,000 - 2,499
    Location: ft. lauderdale, florida
    3,351
    956
    question:....are those bottom times or run times for you first three dives.. ?
     
  10. Storker

    Storker ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 100 - 199
    Location: close to a Hell which occasionally freezes over
    17,202
    13,600
    If ever were to dive first on air, then on nitrox on tables, I'd use the air table through the SI after my last air dive, and then carry the residual PG over to the nitrox table for planning the first nitrox dive.
     
    Norwegian Cave Diver likes this.

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