• Welcome to ScubaBoard


  1. Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

    Benefits of registering include

    • Ability to post and comment on topics and discussions.
    • A Free photo gallery to share your dive photos with the world.
    • You can make this box go away

    Joining is quick and easy. Login or Register now by clicking on the button

PERDIX or PERDIX AI?

Discussion in 'Computers, Gauges, Watches and Analyzers' started by kaaralex, Feb 9, 2017.

  1. kaaralex

    kaaralex Solo Diver

    # of Dives: 200 - 499
    Location: Shanghai
    48
    2
    8
    Unless I win a serious jackpot or find that uncle who was last seen in Hamburg boarding a boat for South America many yrs ago, I am not going to dive CC in the next few years. :) Also, 130m rating is also way more than enough for my diving needs. (BTW, it is interesting that the differences in depth ratings are discussed in detail in FAQ on Shearwater pages, but they are not mentioned in the direct comparison of Perdix and Petrel.) So I do not need to consider other Shearwater models but PERDIX.
    That leaves me w 2 options. I am considering pros and cons of AI model. It is nice to have gas metrics on the screen, however, it introduces one more element which can break, and - more important - an HP one. Also the electronics can break (though this situation is backed up by a good ol' SPG.) Also, monitoring my gas supply using SPG is already something quite automatic for me.

    Let me know if I am overlooking some good reason why to buy AI? I do not want to start any feature nit-picking flamewar, I am just curious if there are some uses to this than what I can see.
     
  2. timbo72

    timbo72 Garibaldi

    # of Dives: 25 - 49
    Location: Melbourne, AUS
    4
    4
    3
    for the price difference I bought the AI, you can add transmitters to your rig at a later time. better to have it and not need it...
     
    Texas Torpedo, rhwestfall and stuartv like this.
  3. doctormike

    doctormike ScubaBoard Supporter Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: New York City
    6,736
    6,624
    113
    If you are going to keep an SPG (you should!) and if you at the point in your diving where you just glance at it occasionally but pretty much know what your pressure is, then there is only one reason for AI - if you are a data junkie. Some people like having that pressure information automatically included when they download their DC into their dive logging software. Other than that, even with a great computer like the Perdix, you only have so much screen real estate. Why clutter it up with redundant information that you don't really need?

    It doesn't sound like you are doing deco, right? If not, then even if your SPG fails and you don't have pressure information, so what? You are situationally aware enough to not have run OOG, so you just make a regular ascent. You don't have to make any hard choices based on that information (like changing gradient factors on the fly because you are both low on gas and have a deco obligation).

    Are you under the impression that an HP leak is more serious than an LP leak? It's actually the reverse.
     
    undrwater likes this.
  4. stuartv

    stuartv Seeking the Light ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: Manassas, VA
    9,458
    5,254
    113
    If you are buying used, get the non-AI. They are going for cheap right now. If buying new, get the AI (because otherwise, you may as well get the non-AI used).

    If you are going to buy new, regardless, I'd say to go AI just because it's not that much more and it will prove worth it on resale later (if you ever sell it).

    For single tank recreational diving, I only have a transmitter on my reg set. No SPG. I like having my tank pressure in the same place as all my other dive data. Only 1 instrument to check and I can do so without using my hands. Plus, the transmitter is less failure points. 2 O-rings instead of 4 or 5, and solid state electronics instead of moving parts. My transmitter is over 2 years old, over 120 dives, still using the original battery, and it has worked flawlessly the whole time.
     
  5. doctormike

    doctormike ScubaBoard Supporter Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: New York City
    6,736
    6,624
    113
    I don't want to start the same old argument again. On the other hand, why not? C'mon, Stuart, we can do this one more time!

    If you read any of the many, many threads on this topic, you always find a number of people (myself included) who have had significant problems with the reliability of hoseless AI. And since it's an Internet forum, people respond to those posts, saying that they have never had a problem with their HAI.

    There is a statistical problem with using that discussion to decide the issue. If - for example - HAI failed in 10% of all units shipped, that would be horrible, completely unacceptable for use in diving, especially without a redundant SPG. Yet even in that situation, you would still have 90% of the people using it (thousands of divers) swearing online that it has been completely reliable.

    So in summary: Lots of people saying they work? Nice but statistically meaningless. A number of people saying that they don't? Raises concerns.
     
    oldschoolto likes this.
  6. guruboy

    guruboy Divemaster ScubaBoard Supporter

    5,043
    802
    113
    I don't think that's how statistics work...

    The total sample size matters for either case.
     
  7. kaaralex

    kaaralex Solo Diver

    # of Dives: 200 - 499
    Location: Shanghai
    48
    2
    8
    I do deco on most of my dives.

    Why LP leak is more serious?
     
  8. doctormike

    doctormike ScubaBoard Supporter Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: New York City
    6,736
    6,624
    113
    Right, but you will never have that information in an Internet forum.

    The point is that posts arguing for relying on HAI based on that person's experience have a very small amount of statistical significance. The reason is that even a horrible DC with a high failure rate is going to have the vast majority of users posting "works on my machine", or words to that effect.
     
  9. guruboy

    guruboy Divemaster ScubaBoard Supporter

    5,043
    802
    113
    Please define HAI and DC
     
  10. guruboy

    guruboy Divemaster ScubaBoard Supporter

    5,043
    802
    113
    This is just your opinion so also meaningless as a datapoint.

    Let's stop hijacking the OP's thread.
     
    Kenkel79 and BurhanMuntasser like this.

Share This Page