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Just got my AOW and might plan a deep dive. Things to make sure I cover off?

Discussion in 'Basic Scuba Discussions' started by xdjio, Feb 17, 2012.

  1. xdjio

    xdjio DIR Practitioner

    # of Dives: 50 - 99
    Location: Vancouver, BC, Canada
    98
    29
    18
    Hi All,

    I just got my AOW cert last weekend, and I have been diving about a year. I feel good in the water, confident, but absolutely humble and ready to learn and improve more. While I have a PADI OW and AOW, all my instructors have been very diligent about incorporating much of their other skills where appropriate - most recently my AOW instructor was a GUE / IANTD guy who's spent a lot of time with the WKPP guys.

    Needless to say, the course was very informative and went beyond the contents of the AOW book material.

    On our deep dive, we had a really good time here in Vancouver, in "The Cut" at Whytecliff. We actually did two deep dives - 121 feet and 100 feet. Both times I felt good - calm, well prepared, etc.

    A couple of AOW buddies and I (who have both been diving about 4 years longer than I have) are gooing to do a dive at Whytecliff in a few weeks. They've had plenty of deep dives too - but haven't been to the part of the cut that I was in and I'd like to show them some of the pretty sponges.

    Since that would be my first "deep" dive without an instructor, I just want to make sure my plan is a sound one:

    1) We'd be doing all the normal buddy checks we'd do anyway
    2) We're all computer divers and are skilled with our various rigs
    3) I was thinking that we drop down to maybe 10 meters, do a systems check, make sure we're all feeling good...
    4) and maybe make a couple stops very quickly on the way down to target depth - like maybe stop at 20 meters, and if good, go to 30.
    5) I don't have a handle on what my SAC is - numerically - but I do have a reasonable overall sense of how much I breathe at 15 - 25 meter depths.
    6) We all have lights and are very familiar with the site overall

    Anything else I should be considering?

    Thanks!
     
    beaverdivers likes this.
  2. Superlyte27

    Superlyte27 Captain

    # of Dives:
    Location: Florida
    2,739
    1,487
    113
    a GUE / IANTD guy? Is that even possible?

    I'm reminded of Bart Simpson when he said "I didn't think it was physically possible, but this both sucks and blows at the same time."
     
    mathauck0814 likes this.
  3. xdjio

    xdjio DIR Practitioner

    # of Dives: 50 - 99
    Location: Vancouver, BC, Canada
    98
    29
    18
    I think he was IANTD long before he went GUE - but I could easily be mistaken!
     
  4. SC_Hoaty

    SC_Hoaty Solo Diver

    # of Dives: 25 - 49
    Location: SC
    5,595
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    You didn't mention anything about gas planning. How much gas did you use the last time you were there? Without the instructor, you may be a bit nervous, and may use your gas faster. What do your buddies think about gas planning for this depth?
     
  5. xdjio

    xdjio DIR Practitioner

    # of Dives: 50 - 99
    Location: Vancouver, BC, Canada
    98
    29
    18
    That is an excellent point! I'll have a word with my buddies about it as they have some more experience with detailed gas planning. As a very rough guesstimate - and given short NDL's, I was thinking:

    1) Don't make the call to go down to 30 meters unless we all have min 1500 psi (we're all diving HP steel 100's) and in all likelihood, we'd get there with much more
    2) Leave depth at 1000 psi (or sooner, depending on prevailing conditions, etc)
    3) Leave a comfortable safety margin on NDL's which means we'd probably stay no more than 8 - 10 minutes.

    Last time I was there, I didn't even stay that long - likely no more than 2 or 3 minutes at 121ft. I did use a noticeable amount of gas, but arrived and left depth with plenty in the tank.
     
  6. beaverdivers

    beaverdivers ScubaBoard Business Sponsor ScubaBoard Business Sponsor

    2,602
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    Have you downloaded and analyze your training dives?
     
  7. lamont

    lamont Orca Staff Member

    # of Dives:
    Location: Seattle, WA
    7,534
    604
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    Yeah +1 on gas planning.

    NWGratefulDiver.com

    Information & Articles

    Rock Bottom and Gas Management for Recreational Divers | Spherical Chicken

    And keep in mind, you were actually quite narc'd at 121 feet, you just don't notice how badly you affected down there yet. You also don't know anything about CO2 buildup or 'dark narcs' and what can happen to you at 120 when its not a happy fun warm narcosis, but things go sideways and CO2 feeds into an anxiety/panic cycle. Its better to stick with 90-100 foot dives and start to 'learn' what narcosis feels like at those depths. That way you can scoot back up to 70-80 feet where your short term memory starts to act better and where the gas and deco clocks slow down a bunch, and where any incipient CO2 hit usually backs off.
     
    Bob DBF likes this.
  8. xdjio

    xdjio DIR Practitioner

    # of Dives: 50 - 99
    Location: Vancouver, BC, Canada
    98
    29
    18
    Lamont - great advice! That was what I was thinking too - but I really appreciate the extra detail on "why". I'd be plenty happy making sure I feel good and solid down at 90ft or 100ft, and doing that for as long as it takes to get really dialled in. Note that my plan won't include going any deeper than 30 meters (aka, 100ft). :) I'm certain I was more narc'd than I knew or appreciated.

    I haven't yet downloaded and analyzed my recent training dives but that sounds like a good plan. Just gotta track down the cable for my Vyper.
     
  9. beaverdivers

    beaverdivers ScubaBoard Business Sponsor ScubaBoard Business Sponsor

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    You should use the Rule of Thirds.

    1st 1000 PSI down, so do NOT continue down with less than 2000 PSI. Start going up!

    2nd 1000 PSI to come up.

    3rd 1000 PSI to do your safety stops and reserve on the surface.
     
  10. lamont

    lamont Orca Staff Member

    # of Dives:
    Location: Seattle, WA
    7,534
    604
    113
    Uhm, no. Don't go down to 30m unless you've planned that, and you should get down there sooner in the dive rather than later -- better from both a gas and deco perspective.

    1300 psi should be your rock bottom on 100s. And that assumes a direct ascent to 50 feet. If you plan to multi-level up the shore and a direct ascent (e.g. under a bag -- which you probably can't do very successfully and may not be safe at these sites?), then you should reserve more (1600-1800).

    I agree. Keep it fairly quick.

    I think your definition of "plenty" needs an upgrade.

    I suspect you probably don't know how to reliably share gas at those depths, either, and haven't been tested under task loading or emergency conditions at those depths (but *please* don't just drop down to 120 and do a gas share to try to prove you can do it... build up with lots of shallow skills practice first...)
     

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