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So what should have happened?

Discussion in 'Basic Scuba Discussions' started by markrodg, Sep 13, 2009.

  1. Ytsejam

    Ytsejam DIR Practitioner

    # of Dives: 25 - 49
    Location: Greece
    54
    0
    0
    A safety stop at 3 meters for 3 minutes at the end of every dive was what I was taught by my instructor. In your post you mention a deeper stop at 5 to 7 meters eliminates more nitrogen. Could you please list some of the sources of the information you cite? I'd like to read up more on this and adjust me safety stops accordingly.

    Thanks in advance!
     
  2. leapfrog

    leapfrog Instructor, Scuba

    # of Dives: I just don't log dives
    Location: 40Žº 34'N -3Žº 55'W
    851
    0
    0
    Hi Ytsejam, Happy to oblige although you are going real fast with your training and dive theory, although there is nothing wrong with that! Before I start listing references on the question of safety stops, deco stops and deep stops, can you tell me if you have a PADI/DSAT RDP (the basic one,blue and white?)
     
  3. Garth

    Garth Manta Ray

    # of Dives: 200 - 499
    Location: North Carolina USA
    1,047
    138
    63
    I think what they mean is that on a recreational dive (one that does not exceed the no decompression dive limits) a 3 minute safety stop is recommended. When this diver used a 25min surface interval he violated the no decompression dive limit and the computer attempted to help him blow off excess nitrogen with a prolonged safety stop.
    I think some of the more experienced divers here would suggest you take more classes to get more information on this ie intro to deco procedures.
    As for me, I can't wait to take some more classes after I get more experience and more logged dives.
     
  4. Ytsejam

    Ytsejam DIR Practitioner

    # of Dives: 25 - 49
    Location: Greece
    54
    0
    0
    Hi, leapfrog. I have both PADI and Buhlmann dive tables.

    As for theory and training, I do like to know the science behind what I do, but I decided to dive some more, do the UTD Essentials course and then enroll in AOW, EFR and Rescue. Tomorrow I' ll measure my SAC, work on my boyancy control and test my new Oly 8000 Tough. So, I decided to walk steady before learning how to run :)
     
  5. Ana

    Ana Solo Diver

    1,351
    921
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    Having a 25 min surface interval violates nothing.

    Having a 25 min surface interval (along with the time and depth of the previous dive) allows the diver (or a computer) figure out what would be safe on the following dive.

    No computer attempts to help blow off excess nitrogen. The computer manipulates data according to its algorithm and displays usable data for you.
    -Looking at the data "before" starting the 2nd dive, provides non deco dive times according to depths. A diver that gives a damn tends to know in advance how long he has at certain depth at this point.
    -Looking at the data in the display "during" the dive, tells you how much longer before he has a deco obligation. Not a suggestion, not a little help; A CEILING. A diver that hits that ceiling should do it "knowingly".

    Years ago there was no safety stop. That came later, as a good idea to allow some wiggle room to the average individual using tables (as opposed to the very athletic subjects used as guinea pigs). It also slowed the ascent at the end of the dive.
    Granted any submersion can bend a diver.
    Putting that aside, skipping a "safety stop" to avoid getting separated in current or avoid whatever is a wise move, and keeps a good dive from becoming an ordeal.
    Skipping a "deco stop" without a truly big reason is taking a huge risk, is not a guarantee of getting bent but the odds are extremely high.

    Confusing a deco stop with a "longer safety stop" is like thinking that someone may be a little pregnant. That is why I believe this person deserves to get the money payed for the dive classes back. Even not knowing all the "WHY's" of the safety stop, they should know is a "good idea" not a ceiling.
     
  6. leapfrog

    leapfrog Instructor, Scuba

    # of Dives: I just don't log dives
    Location: 40Žº 34'N -3Žº 55'W
    851
    0
    0
    I was surprised by your statement that
    I always tell my students that everything they need to know about the RDP is on the tables (i.e. on one side or the oher) themselves. The PADI recreational dive planner tables have some "fine print" on the backside. That's important stuff and not to be ignored, ever.
    Safety stops -- the optional 3-minute safety stop at 5 meters/ 15 feet becomes mandatory if you get within three pressure groups of a no-decompression limit, or for any dive deeper than a hundred feet.

    Emergency Decompression -- If for some reason you exceed a no decompression limit by up to five minutes, you must make an 8-minute decompression stop at 5 meters/15 feet, and then not dive for six hours. If the no decompression limit is exceeded by more than five minutes, you must make a 15-minute stop at 5 meters/15 feet and then not dive for at least 24 hours.

    So I think you should talk to your instructor to find out why he said 3 minutes at 3 meters.

    You mention you also have "Buhlmann tables". Buhlmann Sea Level Tables, Buhlmann Altitude Tables, Buhlmann Sea Level Tables with Deep Stops...? Who gave you, taught you and recommended the Buhlmann table(s) and what for?

    All dive tables do essentially the same thing, just not exactly the same way (and often with surprisingly different results). For example, NAUI tables are a bit different from the PADI tables, and they use different definitions and acronyms -- just enough to throw you off. It's like driving a car where the gas is on the left and the brake on the right, and one calls the gas "accelerator" and the other "velocity increasing accentuator".

    For recreational diving, use and understand one set of tables and stick with them.

    For further information, as usual Scubaboard is an excellent source, you can take a look at this thread:
    Safety stop at 15'..........always [Archive] - ScubaBoard
     
  7. Derek S

    Derek S Divemaster

    1,216
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    I apologize if my posting misled a little. What I meant to say is that instead of the OP's Suunto computer making him do a normal safety stop, it likely put him into deco, and forced him to do a decompression stop instead of the garden variety safety stop.

    At the end of the day, I hope the OP learned a few things:

    -Never feel that you can't 'thumb' a dive at any time, for any reason.
    -Never accept things at face value, especially when your health is potentially at risk.
    -If there is an anchor or mooring line there, use it.

    Safe dives - DS
     
  8. Lucy's Diver

    Lucy's Diver Barracuda

    # of Dives: I'm a Fish!
    Location: New York City
    374
    4
    0
    I'm not quite sure where you got the notion that was advocating some kind of ignore your computer when inconvenient diving practice. My point is that &*it happens and this is hardly an incident to get all spun up on the internet over. Dives go sideways, this one went sideways maybe an inch or two. Relax. This is hardly something to call the Scuba Police over, and I certainly would not be asking for my money back.
     
  9. Garth

    Garth Manta Ray

    # of Dives: 200 - 499
    Location: North Carolina USA
    1,047
    138
    63
     
  10. Garth

    Garth Manta Ray

    # of Dives: 200 - 499
    Location: North Carolina USA
    1,047
    138
    63
    apparently i don't know how to quote yet either sorry.
     

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