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Petrel 20ft safety stop?

Discussion in 'Shearwater Research' started by Julian55, Jan 5, 2013.

  1. exposure

    exposure Tech Instructor

    # of Dives: 2,500 - 4,999
    Location: Paris, France
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    Changing the gradient factor will show you the need of a compulsory stop, no more a safety stop. Isn't it?
    As said, for a safety stop, just count 3 min at 20ft.
     
  2. 616fun

    616fun Divemaster

    # of Dives: 200 - 499
    Location: Indianapolis, IN
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    Ah but Jim, all the other offerings dummy proof with things like safety stops. I agree that it's the perfect computer for someone looking to expand and has a training plan laid out, but this is the second palm to forehead question on the Petrel (the other was about trying to set GF to match his Suunto Gekko) this diver has posted. I know Bruce is shaking his head at these questions...

    I also agree that a Shearwater is more computer than needed for most divers. I cut my own tables and planned my deco for all dives before owning a Predator (I don't own a Petrel, but the algorithms are the same). I still cut tables for back up and could execute a dive off a BT if needed. I'm going to go out on a limb that the original poster may struggle with these concepts. GF just makes their head hurt.

    Like anything, familiarize yourself with the product before buying it because the Internet says it's the best.
     
  3. Jim Lapenta

    Jim Lapenta Dive Shop

    # of Dives: 500 - 999
    Location: Canonsburg, Pa
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    To a point. But how many divers have you seen as a DM have no clue what their computer is telling them? They bought it cause slickster shop owner told them they need it and it looks cool and will get them chicks or studs and will keep them alive and make their dives longer without telling them that they likely will run out of air before their NDL is up anyway. Or how to actually plan a dive. "just keep the computer in the green or just a little in the yellow and you'll be fine". Oh and you really need this heart monitor feature to go with your tank banger and dry snorkel!
     
    616fun likes this.
  4. 616fun

    616fun Divemaster

    # of Dives: 200 - 499
    Location: Indianapolis, IN
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    Come on Jim. I love my heart rate monitor....on my Garmin Forerunner for interval training...

    (Insert sarcasm here)
     
    Jax likes this.
  5. KWS

    KWS ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: SE TEXAS
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    I got home and did the planning mode and there is not a safety stop. The 20 ft stop i configured with is only if deco is needed. I guess i have been just doing them with out preditor derection. I certainly wont give my preditor up though, it is to intuitive to use.

     
  6. Julian55

    Julian55 Barracuda

    # of Dives: 200 - 499
    Location: New Westminster,BC
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    wow a simple question turns into a flame thread, really? The reason I asked about the Sunnto/Shearwater comparison is that most of the divers I dive with use Sunnto so it makes sense to run something similar, I also like that it's quite conservative as I have used one for years. I have done a fair bit of research so please don't imply that I bought this computer for any of the reasons you stated above, my plan is to grow into the functions of this computer as I progress. I'm also quite confident I could count down 3 minutes at 20ft I was just asking if it was built in as I did not see it in the manual I have read multiple times.

    After doing my first 2 dives 30/80 seems pretty close to what i'm looking for, for the people who offered advice thank you very much!
     
  7. ianr33

    ianr33 Solo Diver

    # of Dives: 200 - 499
    Location: Wah Wah Land
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    The only computer I've ever owned that had a safety stop countdown was a Dive Rite Duo. I always found it totally laughable it started counting down a 3 minute safety stop immediately after finishing maybe 20 minutes deco on O2 .

    "Tech" computers let you do whatever is right for you,within some very broad limits. Set the gradient factors to 100/100 to get out of the water quickly,the computer won't mind. (Although your body might! ) Or set the gradient factors to 10/50,do deco for hours. Then add a 5 minute safety stop while you die of hypothermia. It's all up to the diver, who hopefully knows what he is doing.

    To the OP, 30/80 should be conservative,but not stupidly so, with or without an extra safety stop. I use 30/85 on my Predator. If it's clear on an NDL dive I likely wouldn't bother with much,if any, of a safety stop.
     
  8. 616fun

    616fun Divemaster

    # of Dives: 200 - 499
    Location: Indianapolis, IN
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    The simple questions you ask show you aren't ready to think through the set up and execution of a computer using GF as it's algorithm. If you wanted a computer to match profiles of a Gekko because that's what your buddies dive, dive a Gekko.

    No one is piling on you. It's a systemic problem in diving. Those of us that have been around diving for awhile have seen it time and again.

    As I stated (and PM'd you in the other thread) - spend time understanding the theories and algorithms your computer is using.
     
  9. Julian55

    Julian55 Barracuda

    # of Dives: 200 - 499
    Location: New Westminster,BC
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    The only problem I see in diving is the divers who think they are better than everyone else and like to point it out, most people learn from reading/asking questions(even dumb ones)and experience. Putting all the reading I have done with a few dives today and seeing how things work made it all come together(at least where I'm at now) Yes I may have burdened a few tech divers with dumb questions along the way but no one is obligated to reply. The LDS I bought the Petrel from were not even dealers until I asked them to get it so it's not like I saw the pretty lights and bought it. This has been a 3 month process for me and taking recommendations from people who dive recreational and tech, quality/workmanship and customer service were key factors in the Petrel vs another computer, some tech divers recommended it as a great computer to advance my diving with but I guess I should have checked with those who "have been around a while" first.
     
  10. KWS

    KWS ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: SE TEXAS
    4,817
    1,214
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    Julian,
    Lets not start down the us vs. them path. It is not productive. Your profile says you are quite new. It is just the nature of the beast, right or wrong. If you want to se flaming ask about split finns deep diving on air, or DIR supremacy. That should pour on the fuel. Relativily speeking you got off pretty well unscathed.

    I will tell yout hat i have the preditor and untill you asked, i did not know it did not have a safety stop flagged in its software. SO I LEARNED SOMETHING. It took me nearly a year to comit to buying one. I finally got mine from the guy that did my tech instruction. The major strength of the puter is that it is not a recreational device with nanny running in the background, trying to save you from your self. I myself do not understand perhaps more than a few % pionts of what the preditor does. What i have found out is that it is less protective than the recreational units. So when it tells you to do a 5 in stop you do 5 min not 3 or 4. and that you can set the amount of protection/conservatism in the algorithum
    . I run mine at 35/80 or 30/85 the default and will till i find a need to alter. fitness age and a lot of things control that setting. I find its most valuable asset is that i dont need a book to run it. the menu is good at leading you where you need to go. For me this is a must when it comes to gas changes such as deco. The task loading is much less for me when using the predator functions and mainiaining depth conptrol. My eye sight is not as it once was and i can erad the display without perscription masks. Just dont let the sunlight beat down on the face and it should last you for years or until they start using someting else other than He for trimix. Another thing is that for many use of a comuter in diving is considered a crutch and a FAILURE POINT waiting to happen. You can always take a second rec computer shut the alarms off and strap it somewhere. When you start deep stuff you can re-evaluate your computer use.
     

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