• 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

console or computer. Configuration enquire.

Discussion in 'Advanced Scuba Discussions' started by ignacioblanch, Aug 23, 2008.

  1. ignacioblanch

    ignacioblanch Instructor, Scuba

    # of Dives: 500 - 999
    Location: Buenos Aires, Argentina, South America
    Hello everyone. This is my first post in the forum and I couldn't find any topic about this. Please, if I'm asking something that it's been already answered I apologize. Let me know and look better for it.

    This post is to see what your advice from a more experienced point of view is. (I am always talking about recreational diving. Even though I'd like to do some tech in the future)

    I'm getting some new gear and this "dilemma" between Analog and Digital, computer with air integrated or not, suddenly came to my mind.
    I am not sure how reliable is to have a console "Suunto COBRA" style, or if its better instead to have an analog console with a suunto Vyper on my wrist. Or to have a Cobra with another computer without air integrated on my wrist.

    Is it reliable to go all digital without analog elements? Am I being too paranoid?

    1) From the point of view of safety and from the practical point of view as well: which of this one do you think is the better configuration? Everything you want to say about this is going to be very welcome.

    a) Cobra
    b) Cobra and another computer on wrist (no a/i)
    c) Analog console with a computer on wrist (no a/i)

    I'll be looking forward to reading all your answers.

    Thanks a lot!

  2. nereas

    nereas Solo Diver

    # of Dives: 500 - 999
    Location: Expat Floridian travelling in the Land of Eternal
    All of the SUUNTO dive computers work extremely well.

    For a new diver, one SUUNTO dive computer should be plenty. A backup would normally not be necessary.

    But if you truly want a back up, then a simply analog dial depth gauge would be plenty, together with your waterproof wrist watch. If you want a digital back up, then UWATEK makes several "bottom timers" (combination of digital depth gauge and timer) not too expensive.

    I dived with a wrist watch and an analog depth gauge for many years, and this worked fine.

    I added a SUUNTO Vyper wrist computer eventually, and have enjoyed it very much, since it accounts for depth and time more precisely than is possible with only a watch and a depth gauge.

    So afterwards the wrist watch and analog gauge were then replaced by an UWATEK bottom timer as a backup.

    Then finally, the UWATEK was replaced by a multi-gas helium tech computer (DiveRite NiTek HE). So my SUUNTO is actually now my backup, in gauge mode, and the NiTek is the primary computer.

    Backups are nice, and for simply NDL purposes, either a watch and analog backup or else a bottom timer backup is fine. But backups are not really critical as long as your buddy stays nearby.

    I would avoid console models, and stick with wrist models. Consoles work fine for rental scuba gear, but awful in all other practical respects.
  3. LowVizWiz

    LowVizWiz Instructor, Scuba Staff Member

    # of Dives: None - Not Certified
    Location: South FL but way too far from shore...
    Hey Nacho, welcome to the board, these questions come up all the time and it's fine to ask. No one was born knowing everything they know, even those who act like it!:lotsalove:

    You will get a ton of varying opinions and choices, but it really only matters what works for you as long as it safe.

    I personally dive a sunnto Cobra and also have a Vyper, do I need both? Nope! Do I need either? Nope, but they sure are nice to have.

    To answer your question:
    If I could do it all over again I would get a wrist computer with AI and just carry a back up spg. And yes you're being too paranoid, want to buy my cobra and Vyper? :D

    Your profile says you have quite a few dives under your belt, so I assume you're pretty comfortable diving tables and square profiles, but you don't mention why you now want a dive computer when you could just replace what you're already using!

    Are your buddies diving computers and you feel you're missing out diving square profiles?

    If you just want a new dive toy then by all means go for a computer and learn to use it before you dive it. What I mean is don't show up to the boat and read the manual on the way to the dive site!:shakehead: Also, skip the digital compass they are worthless IMHO!

    If you have more specific questions about either the cobra or the vyper feel free to send me a message and I'll tell you as much as I know about it.

    Good luck!
  4. TSandM

    TSandM Missed and loved by many.

    # of Dives:
    Location: Woodinville, WA
    This goes a bit to the question of how much redundancy you feel you need or want for the dives you are doing, and what information you feel you must have to be safe in ending a dive.

    I don't think anybody has any real data on how frequent dive computer failures are, but if you read the forums here, it's clear that they do happen from time to time. It can be something as simple as having a battery die, or a computer flood, or something as complicated as what happened to my Vytech, which one day simply decided not to display anything but weird, partial numbers that didn't resemble any screen it was supposed to have (it was toast -- I lost a bunch of undownloaded dives that way!)

    I don't think anybody knows how often analog pressure gauges go down, either, except that they also do. I lose one from a face that leaked; the gauge continued to work, so I didn't have to abort the dive, but over a couple of days, the algae grew in the water enough to obscure the needle, so it had to be replaced.

    Transmitters for AI computers seem to be a bit more temperamental than the gauges themselves, in that their batteries don't last as long, and they can have problems synching with the gauge. I've seen enough problems with them that I would be reluctant to rely entirely on that system for pressure information, because it's a nuisance at best if you can't get it to work.

    I dive with a wrist computer which is NOT air integrated, and an analog SPG. I know my gas consumption well enough to be able to predict it from my depth, and to be able to estimate my depth from my gas consumption. I also dive with a reliable buddy, so some of my redundancy that will allow me to safely end a dive is on my buddy's wrist. My husband dives with a Vytech with a transmitter, and a Cobra, so he has EVERYTHING in duplicate.

    You just have to decide whether the (probably low) risk of having an electronic device go down is worth it to you. If you do a lot of very expensive travel diving, you might never want to take the chance that a failed gauge will abort or prevent a dive. If you do mostly walk into the water local shore diving, having a gauge go down on you would be a nuisance, but not a disaster. If you dive solo, you might opt for more redundancy. I don't think anybody can give you any kind of hard and fast rule about what is best.
  5. 1_T_Submariner

    1_T_Submariner Solo Diver

    I dive with a wrist mounted Ai computer and an SPG in a console and since there is already a non AI computer in the console I have left it there. I do check my SPG occassionally, it always agrees with the AI on my wrist. I too agree what TSandM said about knowing your gas consumptions, I am never realyl surprised by either gauge when I chack my air (think about how ofter you are surprised by the speedometer in a car you have had for years).
  6. Doc Harry

    Doc Harry Solo Diver

    # of Dives: 500 - 999
    Location: Appalachia
    Hi Nacho,

    Remember this:
    1. You NEED to monitor depth, time and gas
    2. You don't absolutely NEED to monitor N2 loading with a computer, you have tables for this
    3. If you are using a computer to limit your N2 loading, and it fails, you have to stay out of the water for 24 hours

    So, consider this:

    1. If all you have is an AI Cobra and it fails, you dive is over. Furthermore, you have no way to monitor your gas on the ascent. You can't even keep track of how fast you ascend. You lose your Cobra and you have NOTHING. Then you have to stay out of the water for 24 hours.

    2. If you have an AI Cobra and another non-AI computer, what happens in a failure? If your Cobra fails, you still have depth, time and N2 data on the backup computer but you still cannot monitor your gas. The dive is over. You have to attach an SPG to your regulator before you can dive again.

    If your backup computer fails, no big deal.

    3. If you have an analog SPG and a non-AI computer, what happens in a failure? If your computer fails then you lose N2 and depth data, but you can still monitor you gas. The dive is over. Then you have to stay out of the water for 24 hours.

    If you SPG fails, the dive is over. Get a new SPG when you get out of the water. You can dive again right away.

    4. If you have an analog SPG and a depth gauge/watch and a computer, what happens in a failure? Think it through.

    FYI, I dive with an SPG, digital depth gauge/watch and sometimes I use a non-AI computer if the boat requires a computer.
  7. TSandM

    TSandM Missed and loved by many.

    # of Dives:
    Location: Woodinville, WA
    I'll disagree a little with the prior post. If you have logged your dives as you did them, you can use tables to assess your status, and if the tables clear you, there is no need to stay out of the water for 24 hours.
  8. spectrum

    spectrum Dive Bum Wannabe ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: The Atlantic Northeast (Maine)

    Your question hits a lot of concepts and it helps if you pick them apart a little. Your statement that you want to evaluate this from a recreational standpoint is important.

    Take reliability for instance. You can consider it from a standpoint of dive safety as well as likelihood of it needing repair and the costs & delays associated with it.

    Why do we dive with instruments? We want to know how much air we have available, how deep we are and how long we have been underwater and in certain portion of the dive profile. You or your computer will use this information to manage your air supply and to keep nitrogen loading under control. A recreational dive by definition means that at any time in the dive you can return to the surface at 30 FPM though deep stops and safety stops widen safety margins and reduce stress.

    Lets take care of integration first. This includes 2 flavors, direct and wireless. A wireless system involves screwing a pressure transducer / transmitter into a high pressure port of your 1st stage and adding a receiver to the dive computer. The direct format places the computer at the end of the high pressure hose in a boot or console where a pressure transducer detects cylinder pressure and passes it to the computer. From a standpoint of cost and failure points its an inescapable fact that you are giving things away here and wireless just exacerbates the situation. The failure rate is real but hard to quantify and for recreational diving represents minor risks. If it dies you go up, end of story. If you are a gadget junkie and have the $$ then integrate all you want but really all of the integration you need is between your ears. For that matter if know what you are doing all of the integration you WANT may be between your ears.

    The biggest risk in in a highly repetitive/vacation situation is that you need to rejigger your dive planning scheme to make up for the lapse in data.

    The analog depth gauge is often sacrificed to make room for the computer in a console or divers may choose to go to a solitary SPG with a wrist computer. The loss of depth data is not the end of the world. You will most likely have a buddy that will be monitoring the ascent rate. Hopefully it is slow enough that it is inherently safe. The are also bubbles, visual references and sensing your ears that can be used to avoid an overly fast ascent.

    In some ways you might be more concerned about loss of cylinder pressure data. After all you can usually be cured of DCS but drowning is hard to come back from. However, again remember that you are monitoring your instruments during the dive and when it goes bogus you end the dive. You will lack the reassurance of rechecking your pressure but if you don't have enough to surface safely then what the heck were you doing staying down there in the first place? Here again if you should run short your buddy is a back-up.

    So in the recreational realm you have a of of built-in safeguards that give you an easy out. As you go technical and need to manage decompression schemes things get less forgiving and the need for redundancy creeps in.

    Personally I dive a 3 bay console with an SPG, non integrated computer and compass. It's all in one place, I never forget it and it never gets away. I run it on a short bungee clipped to my left shoulder and it's right there when I want it. I do strongly suggest that if you go the console route that you go with a 42 inch hose. That is the trick to having the console work nice for navigation. For me and my wife the standard 36 inch hose kept it too low and tight to be comfortable.

    If you want to go wrist mounted it is certainly a valid configuration and really comes down to personal choice. In my opinion it comes down to personal comfort and choice. Neither will make you a better or safer diver.

  9. LowVizWiz

    LowVizWiz Instructor, Scuba Staff Member

    # of Dives: None - Not Certified
    Location: South FL but way too far from shore...
    I agree with you. Always keep a back up time piece and watch your depth. If you know what your deepest depth and bottom time you can use tables to get back in the water.

  10. Colliam7

    Colliam7 Tech Instructor Staff Member

    # of Dives: 1,000 - 2,499
    Location: Hillsborough, NC
    Although the topic has been discussed before, I am not surprised you can’t find useful threads – I couldn’t either, when I just searched a few minutes ago (using ‘analog’ digital’). Perhaps, other responders can offer links to relevant previous threads. The issues I associate with the computer decision you are facing include 1) purpose of the instruments, 2) reliability, 3) convenience, and 4) expense: For me, ‘practicality’ is a combination of ‘reliability’ and ‘convenience’ with a dash of ‘expense’ thrown in, so I don’t add it as a separate issue.
    1) Purpose: A) Pressure; B) Depth; C) Time; D) NDL data; E) History
    First, a caveat about purpose: my comments are general, and predicated on a level of dive planning being done in advance - I know the depth of the site I am diving, I know my NDL for the dive, etc. Among these data items, pressure is, to me, the most immediately critical. If I lose pressure information during a dive, the dive is over. I can, and definitely will, ascend using my buddy’s depth and time information, which is not specific for me. If I lose depth and time, but have pressure, I can continue the dive until I reach my (or my buddy’s) pre-determined ‘turn pressure’, IF I already know that there is little risk of hitting a NDL for the particular dive. For me, the usual rate-limiting factor is air supply, NOT time. Obviously there are exceptions – you are diving a wall where you can exceed a maximum (depth e.g. 130). But, overall, pressure is the key.
    2) Reliability: the perception exists that electronic gauges are somewhat less reliable than analog gauges. And, the perception exists that hard-wired (hose to computer) is more reliable than wireless (transmitter to computer). These are perceptions, not necessarily documented by objective data, at least as far as recreational diving use goes, and particularly in regard to the ‘hard-wired’ digital approach. But, even if opinions on SB generally suggest greater, or equivalent, analog reliability for recreational diving, the failure rates are so low that it is hard to make statements based on objective data.
    3) Convenience: A number of people go wireless digital, in order to reduce the number of hoses by one? You still use the HP port, for a transmitter, but you don’t have the hose. Is it more convenient to be able to look at your wrist, or have to unclip your console, or extend it on a retractor (ooh, NO, Mr. Bill, not a dreaded RETRACTOR) to look at it?. The ‘wrist-mounted vs console mounted’ computer issue has been extensively discussed. A slight overall preference for wrist-mounted over console-mounted computers seems to be present on SB, but either approach is fine. I prefer wrist, with an analog pressure gauge, but that is me.
    4) Expense: Generally, AI (digital) is more expensive than non-AI (analog). Wrist-mounted AI (i.e. with a transmitter) is more expensive than console-mounted AI.
    For recreational diving, it is acceptably reliable to go all digital. The Cobra approach is digital, ‘hard-wired’. Lots of people dive this way, and they dive safely and their instrumentation is reliable. For recreational diving, the probability is you will be diving with a buddy. If your computer fails, and you lose pressure, the dive is over. Ascend using your buddy’s data (depth and time), do your safety stop and exit the water. If you lose depth but know pressure, not necessarily a problem. Dive until you reach whatever turn pressure was established for the dive, and ascend. I don’t think you are being too paranoid. You have to do what you are comfortable with. Some Sbers are not comfortable going all digital. Others are. Irrespective of the data available, a lot depends on YOUR level of comfort.

Share This Page