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V-Planner

Discussion in 'DIR' started by Rainer, Mar 2, 2009.

  1. Rainer

    Rainer DIR Practitioner

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    First, I'm NOT looking at having a precise conversation about specific decompression profiles in a public forum.

    That said, I just got a copy of V-Planner from a buddy. I do all of my T1 dives using RD. I have a copy of DP that I also play with (modifying schedules to get them to look like what I've been taught; i.e. oxygen window, deep stops, etc) when checking dives outside my experience zone.

    I know lots of people use VP, but I was pretty surprised when it spit out schedules that look pretty different from what I would do for a typical T1 dive (say 30 minutes at 150'). In particular, at +2 conservatism (how the software came set up), it calls for nearly no time at the 70' switch and more time than I would do shallow (20' and 10').

    Is this standard for VPM schedules from VP? Are there tweaks I can make to generate schedules more in line with RD? I know I can force extra time at the switch, and putting the conservatism at 'nominal' takes away from time shallow.

    Really just wondering if this software is useful for DIR dives.

    Thanks.
     
  2. amascuba

    amascuba Instructor, Scuba

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    Location: Austin, TX
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    I would say yes. Recently GUE published a SOP manual to registered members. Here is what it has to say about Decompression Ascent Profiles:
    Deco_Ascent.JPG
     
  3. Rainer

    Rainer DIR Practitioner

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    Hmm, from a few PMs and e-mails I've received since posting this, most users have suggested VP is pretty lame for planning the dives we actually do. While the total amount of deco required is pretty close using +2, it's all done at different depths.

    Short of hard coding all the stops I'd want to do anyway, and seeing how bad VP is going to yell at me, I think I'll just stick with DP unless someone has some good suggestions for tweaking VP.
     
  4. rjack321

    rjack321 ScubaBoard Supporter ScubaBoard Supporter

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    Since you are using standard gases its not that difficult to hard code your stops in V-planner. Leave the 10ft "stop" empty but as you play with the bottom time and/or depth you can see when VPM starts adding time shallow, meaning your profile doesn't have enough deco for the depth/time.

    Personally, RD in its pure form does not work for me. Esp. on a repetitive dive.

    I have figured out that I am about +3.75 on VPM. For many profiles I have a pretty good idea what that means. But for newer to me profiles there is no way in hell I will use RD as a "starting point" because I know it will be inadequate. So to know how much time to add I use VPM and hard code my stops. Then change conservatism between +3 and +4 to gauge how much extra time I'll need.

    So far my T2 rule of thumb is:
    do all the O2 time at 20ft,
    gas break can count as O2 time,
    5-6 min ascent
     
    Last edited: Mar 2, 2009
  5. rjack321

    rjack321 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
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    I find it quite interesting how much UTD has embraced "expedition" deco. Our plans at the "trimix1" level are shaped around gas volumes.
    "Max 60mins deco right"
    "yup"
    "ok lets go"

    Whomever is deco captain calls average depth as we begin the ascent and we all know the (shaped) schedule from there, poof. We typically do 50ft up from the bottom instead of 80% of ATAs or 75% of depth as the first deep stop. 50ft works for all but the shallowest (e.g. 80ft deco dives). I'm only doing those in places like Mayan Blue where you are swimming up slow enough and with a minimal enough obligation that the deep stops really aren't precisely timed anyway.

    My 'all O2 time at 20ft' is definately an anomaly and most of my buddies just tell me to take over as deco lead once we hit 20ft (if I'm not already). They know I won't do something dumb.
     
  6. amascuba

    amascuba Instructor, Scuba

    # of Dives: 500 - 999
    Location: Austin, TX
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    I'm not UTD/GUE Tech qualified. My closest qualifications are TDI Advanced Nitrox/Decompression Procedures, even then I don't jump off the deep end of that certification with nitrox or air. Honestly, my TDI class mostly revolved around dive planning and some what if scenarios. It was good in that arena, but it could have been better in other areas.

    Around my neck of the woods we have only 1 dive site that is deeper than 100ft (It's deepest point is around 285) and it's on private property and a PITA to get access to (I only have 3 dives at said location). So most of my dives are minimum deco dives. I'm familiar enough with minimum deco that I do those on the fly and my buddies and I do the dives around gas volume as well. On dives that I'm planning actual deco I just use EAN32 w/ O2 and plan the dives and write the information that I need in wet notes. I've read the ratio deco PDF a few times and understand the fundamentals of it, but at this point I don't rely on it as a primary use tool. I would use it in a pinch if the dive as planned didn't go well.
     
  7. deepstops

    deepstops Blacklight Poster ScubaBoard Sponsor

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    There's an option in VPlanner to force the 3-5 minutes at the gas switch to better utilize the O2 window.
    None of this is science nor is any of it right or wrong but I find VPlanner works great for me. (I'm merely a Fundies grad and with a TDI trimix card and ~150 T1/T2 level dives, all on VPlanner).
     
  8. Rainer

    Rainer DIR Practitioner

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    Brian, there's really no question the VP profiles are working for lots of people. That's not the issue. I'm just wondering if this software can be used to help plan dives for some of us who were taught a different set of tools (yes, the extended gas switch feature helps some, thanks for pointing that out). The fact VP, as I have it set up out of the box, provides profiles incompatible with how an entire agency or two of divers plan for deco isn't too helpful. I don't want to reach 70' and have one teammate planning to go with the VP schedule and another one using RD, regardless of the fact both profiles would likely get us out of the water just fine. I want everyone on the same plan.
     
  9. rjack321

    rjack321 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
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    Yeah unfortunately that is a limitation of GUE's Tech1 class right now, since its encouraging software quite a bit more than it used to. My T1 class used decoplanner with 30/85 GF ad nauseum until everyone clicked into "yes RD gives you enough time" mode (which didn't take long cause there are only so many permutations in the 130-160ft range).

    We then had additional lecture modules on deepstops, O2 window and gradient (shallow) stops. We planned our experience dives on the dock in our wetnotes; the lappy wasn't even around.

    GUE's version of RD has morphed since then (e.g. linear ascent from 70 to 30 and similar modifications) and overall RD seems to have been de-emphasized (just based on what I have heard).

    So I guess your only solution is to get some regular buddies and get on the same page. Cause V-planner is certainly going to give you slightly different profiles from 20mins at 150 vs. 25mins at 140 (which RD would treat the same).
     
  10. dsteding

    dsteding DIR Practitioner

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    Location: Seattle, downtown
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    Gawd, that is obtuse.

    15 second pause/slide for 15 minutes or less of deco?

    30 second pause/slide for more than?

    O2 use if available? *** does that even mean? As in, "if you still have O2 available, use it on the 6 minute ascent, if you ran out of it, use something else. Or, if you are using O2, ascend on it from 20 feet (duh)."

    Follow planned ascent until 20 feet? Then what? Follow the unplanned ascent?
     

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