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Stage Dive Planning

Discussion in 'Technical Diving Specialties' started by ianr33, Jun 30, 2006.

  1. limeyx

    limeyx DIR Practitioner

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    Well, if you have to ask, maybe the class would be a good idea :)
    That was my only point. Seems like if you were trained to use a bottom stage, you wouldn't have to ask the internet. If you weren't, you might want to reconsider diving with it.
     
  2. Thalassamania

    Thalassamania Diving Polymath ScubaBoard Supporter

    # of Dives: 5,000 - ∞
    Location: On a large pile of smokin' A'a, the most isolated
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    How about a deep stop on the way back up followed by 7 min at 10?

    I figure that the dive'll use need about 100 cubic feet (at .5scfm), so one set of doubles should do you fine.

    The stage is nothing more than practice.
     
  3. ianr33

    ianr33 Solo Diver

    # of Dives: 200 - 499
    Location: Wah Wah Land
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    No thanks. I prefer not to blow off deco stops suggested by V Planner

    And I figure that at 0.6 which is what I use for planning it will use 142 cubic feet(see my original post). So allowing 50% extra for contingencies I need to carry around 210 cubic feet. That will not fit in a set of Al doubles

    Sheesh !!!
     
  4. ianr33

    ianr33 Solo Diver

    # of Dives: 200 - 499
    Location: Wah Wah Land
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    I have done the class.

    Have You?
     
  5. Scared Silly

    Scared Silly Regular of the Pub

    # of Dives: 500 - 999
    Location: on the path to perdition
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    I agree do a deep stop. However, I would also look at switching to deco bottle of 40% at 80'. It will speed things along a bit.

    Curious to know how you got 100cuft? I get just 136cuft for a sac 0.5cuft/m
     
  6. ianr33

    ianr33 Solo Diver

    # of Dives: 200 - 499
    Location: Wah Wah Land
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    V- Planner uses VPM. It knows all about deep stops !!!!!

    Switching to 40 % would only knock off a minute or 2 of deco and a stage of 40%(why 40%?) could not be used at the planned maximum depth.The deco is minimal and I see no need to carry 4 tanks
     
  7. cyklon_300

    cyklon_300 Loggerhead Turtle

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    what's worth seeing at 110' for 40 min? Isn't all the Carib scenery pretty much the same old stuff...parrotfish, soldierfish, yadda yadda, snore...

    This is presumably a vacation, right?...why not just stick to NDL/single 80/snorkeldorkel dives and drinks with little umbrellas in them and you won't have to mess with all that tech-nerd doubles/stage/VPM crap...
     
  8. ianr33

    ianr33 Solo Diver

    # of Dives: 200 - 499
    Location: Wah Wah Land
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    Your first post in over a month and this is what I get?

    Sheesh :mooner:
     
  9. texasdiver13

    texasdiver13 Angel Fish

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    I just got back from little cayman and dove 32% on bloody bay wall. First dive was max depth of 110' for 50 min but i normally went to 85' for 15 to 20 min then up between 40' and 25' on top of the wall for the rest of the dive. I highly recommend reef divers if you are looking for a good dive op.


    Dave
     
  10. Thalassamania

    Thalassamania Diving Polymath ScubaBoard Supporter

    # of Dives: 5,000 - ∞
    Location: On a large pile of smokin' A'a, the most isolated
    22,171
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    Don't you think your making more of a production than one needs to out of a 110 foot for 40 minute wall dive?

    Training is great, practice is fine, especially tank handling. But here's how I'd handle the decom and the gas:

    OK, 0.6 scfm for me and 0.6 scfm for my buddy.

    For a 110 ft dive for 40 minutes that’s 104 cubic ft for gas that I’d need.

    50% reserve is overkill. To wit:

    Gas for ascent for me and my buddy = 4 cubic ft.

    3 min deep stop at 55 ft for me and my buddy = 10 cubic ft.

    10 min at 10 ft (7 at 10 required) for me and my buddy = 16 cubic ft.

    Reserve for an extra 10 min decom (in case of one step too deep or too long) for me and my buddy = 16 cubic ft.

    Bingo air is 46 cubic feet, that’s 1800 PSI in one tank or 900 in both. Extra reserve if everything goes wrong at the worst possible moment is 10 cubic ft.

    If this is an “operational” as opposed to a training dive, I suggest that you are overcomplicating it and making more of it than need be. The object should be to get to 110 feet for 40 minutes with as little fuss and bother possible, commensurate with a reasonable level of risk avoidance. Might I respectfully submit that you are taking a rather simple, one-step-over-the-line dive into a more dangerous realm, and the extra hazard is self-imposed and unnecessary?

    If you insist on making a major production of it, OK, that is your choice. Then your plan to stage down is a good one, and stick to your plant to switch to back gas with 300 to 400 psi left in the bottle. That means that you don’t suck it dry and are not in danger of HAVING to make a switch without preparation.

    V Planner with two steps of conservatism is, of course, your right … but, once again, I think its overkill. You are, I feel, correct to not to use any other gases mix. The only thing that I’d consider is finishing up on pure oxygen, but I’d do that anytime it was possible.

    Have fun.
     

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