Do you really understand your computer, or is it a threat to you?

[DandyDon]

I’ll admit that I didn’t understand mine when I first took it ocean diving. No one impressed on me how important this is – plus it’s a four hour drive each way here on the high desert to practice dives, so I thought I’d figure it out as I went, relying too much on the plastic cheat-sheet that came with it. But I’ve recently seen worse, and want to open this up for more informed opinions than mine…

I was on a wreck diving boat with a lady who had an Aires/Pelagic, and since we were doing the same Nitrox blend every dive for three days – she just left it on the original setting for the second dive. She had not turned the Default off – which I do if I’m diving the same blend from the same banked mix, so her second dive went with Pelagic Default settings, locking her out.

It was her last dive of the day, and the DM she was buddied with felt she was well within safety range, so he pulled the battery that night, long enough to reset the computer. Yet, the next day, he and another DM gave her incorrect advice on how to deal with the Default, as they were both used to a brand that handles Default differently. I did get a chance to explain Pelagic Defaults to her, help her with turning hers off, and stressed the importance of knowing your computer well enough to operate it safely, as it’s not there to baby-sit.

One pet peeve of mine, which came up here, is the divers who buy a computer and try to dive them with just the cheat-sheet, like I once did. I’m tempted to suggest throwing them away, but – at least read the manual until you know it well, work the computer at home until you know it well, and run simulation dives until you can plan a dive with the sim feature – with various contingencies.


And last night, I received this from a new member who was afraid to ask a question on SB. This is a problem in itself, but I’ll deal with that elsewhere…

I was reading your post in one of the threads about going up in the yellow. I have an Oceanic Versa Pro and I have gone up with one bubble in the yellow. Is this bad? I am going to find that manual and read it. I don't even know what it will look like if I go into decompression. Anyway, is being in the yellow when you surface bad? Thanks. I didn't want to post this publicly because I hate it when people say mean things about my not having knowledge...and I am sensitive to this. Anyway, thanks for your time.

Well, I am no authority - certainly not a professional or anything, but I'll give you my opinions and understandings.

Bad - yes! or so the implication goes. Loading nitrogen is all a matter or degree, and there's no guarantee that you will take a hit if you exit in the red, nor that you won't if you exit in the green. Most divers have not been checked out for a common heart defect of PFO, which makes a person much more prone to a hit. DAN had a good article on this recently. I presume you are a member; you can access that article on their site if you don't still have the magazine.

The Pelagic computers (Oceanic & Aires) suggest that Green is go, Yellow is caution, Red is don't, but only as a guideline. Yet they're good guidelines, based on much study and experience. All I can say is that you are a lot better off leaving the water in the green than in the yellow - which is their suggestion as I understand it.

Your statement that really concerns me is "I don't even know what it will look like if I go into decompression." I suggest getting the manual out and not laying it down until you know the computer very well, including how to run simulations.

I do lots of sim diving, to see what it'd be like to go into deco, and how long of a safety stop it would take to get back to green. Actually, if you go into deco, you will probably only be able to leave with one bubble of yellow, as that really loads you up, but it's good to have done this in your easy chair before it can happen on a dive.

I’ve done lots of sim dives - like going to 200 feet on regular air, just as a bounce dive, to see what it'd take to get out of that. I hope to do 200 someday with a technical instructor, and different diving planning, but it's still interesting to feel the dive thru the eyes of the computer.

I remember one time I was doing one of these sims, screwed up, kept falling to 235, and I got all excited - which is good practice in case of the real thing. Get involved with the sim dive, just like a good actor does his part. But we do it so we'll have some experience when the dives go bad.

Anyway, the answers are basically: Yes, leave the water in the green, and Learn your computer will.


And please – everyone spare this thread the common discussions about liberal vs. conservative computers. If you want to enjoy that discussion again, please do so on another thread, and discuss the importance of knowing and working your computer well on this one.

Thank-you for your cooperation!


Added after some discussion...

Aires and Oceanic computers are both Pelagics, with extremely similar models. Owners manuals can be word for word then same.

 

[Michael Schlink]

DD, I like the looks of this thread-nicely done-I hope it runs well
As for me yes I understand my computer(s) as I understand most all computers. I have been diving with a computer for quite a while and have quite a few in inventory.
Your post brings to mind another questions which is how many divers have actually any TRAINING in using a dive computer. An unfortunate trend I'm seeing is the student diver or new diver(same thing in my opinion) are still getting a heavy lesson in dive tables and a short blurb about computers and then encouraged by the dive shop to purchase a computer-why-because " it'll give you more bottom time" and then they're off to the Carib. or where ever with their new toy with little understanding of how to dive with a computer and even less understanding (as you are pointing out) of how to "read" their own computer.
A clear example of this is when I see someone posting that the reason they don't like a particular computer is because they think it's "too" conservative.
I'll be watching this thread
Good Luck and again DD nice job-M

 

[RICoder]

This is a great subject, and I'm curious to hear what everyone has to say.

For my part, I have been diving for a little over 4 years, and have never NOT used an air integrated computer. As such, I am quite familiar with my particular model (SUUNTO Cobra), and a few others.

My biggest complaint in this area was my PADI training. Like Michael Schlink said, you go through the class and they mention computers in passing, and that's that. I went to my instructor for guidance on my computer and came up flat. Luckily for me, my local dive shop is full of gurus who love to explain techy stuff, so I got my instruction there. I would think, at this point, PADI would get with the program and at the very least provide some sort of instruction on this subject during an open water course.

 

[MaxBottomtime]

I think the main reason the agencies teach tables over computers is the fact that dive computers are no more/no less than using a calculator for simple math. Most of them are based on the same algorithyms as the tables, or very similar. Basically, computers do the depth averaging for you so you don't have to count everything as a square profile. It would be great if everyone could do this in their heads as fast as a computer in case the computer takes a dump, but suggesting divers ween themselves off of their computers is like asking people to toss their calculators in the trash. Also, all dive computers have a LOT of conservancy built in. They can't tell your age, fitness level, whether you got enough sleep the night before, whether you closed the bar before getting on the dive boat or if you are wearing proper thermal protection. They are simply an electronic tool designed to make your dive planning more convenient. They are not the evil devices described by some, nor are they meant to be followed blindly. If divers have a good understanding of basic decompression theories taught in their classes, they should have no trouble understanding the information a computer gives you.

 

[retlaw]

my dive buddy and I only found time to read the manual for our cobras on the flight out to Victoria where we were doing Our OW & AOW dives , by the time we arived we had the basics down as to how it worked and just needed some actual use time to get more comfortable with it .
Thankfully Our Instructors took the time to teach us how to use them effectively and that helped alot , and they kept quizing us on them throughout the course .

I guess we got lucky .

so now I understand the computer , just need to log some time with it now to "advance our relationship" to the next level

 

[DandyDon]

so now I understand the computer , just need to log some time with it now to "advance our relationship" to the next level

Cool. Run the simulations. Run the sims. Run the sims. Run the sims.

I don't like turning mine on in the air, as the landing will kick in a shallow dive for hours. Turn it on before you take off, at least, except I live at 3,300 feet. I wait until I get to Dallas or Houston. ilot:

 

[lostinspace]

I think you pay your money you take your choices.
My husband/buddy & I bought identical UWATEC Smart Pro computers. Paying a bit (I cant say little as they were expensive) extra gets you simple easy to read screens that show you precisely what is going on (once you have read the manual).
It also gives me altitude differences - ie it switches itself on when it works out there has been a significant altitude switch. It also tells me when it is inadvisable to increase my altitude.
I know my computer incredibly well. But.... I do rely on it heavily as well. However, if it blows out on me then the worst that will happen is I have to wait (and would wait) 24 hours before starting with a new computer. Yes, that could be a bummer on a holiday, but so is DCS - I'd just spend some time chilling by the pool with a beer

 

[jbd]

I understand the part of my computer that I use. How deep am I and how long have I been below 5 feet. I don't use the nitrox feature very much so I have to look at the book to see which buttons to push to set the O2 %. Everything else is bells and whistles I dont use.

 

[diverbrian]

Personally I think that training agencies push training tables for a couple of reasons...

One of them is that is easier to show nitrogen loading and basic deco theory with a table than a dive computer. The letter groups show progressively high nitrogen loading. That is easy for students to relate to.

Another is that not all students will buy a dive computer. Let's face facts, I dive with many people anymore who still dive tables (and barely dive the tables as their diving isn't anywhere near agressive enough to push the tables to any extent). The other extent of this group are techies who use nothing more than a bottom timer and an iron clad plan.

Having said that our shop now spends a segment of the course discussing dive computers and how to use them in the open water. The students are given cobras to use for there OW training if they haven't purchased computers already.

I had to learn on the fly myself and had a dive buddy "bend" my Mosquito because she didn't realize the difference between the air that she was diving (still not nitrox certified, LOL) and the EAN36 that I was diving. She was used to doing beach dives that are difficult in their own right but deep if they reach 25 ft. So, tables weren't even an issue in spite of her .3 SAC.

We were diving off boats that weekend and did a couple of deeper dives every day for three days. These dives where in the neighborhood of 85-50 ft. By the end of the second day, she informs me that sent the computer into deco. On the morning of the third day, she thinks that the computer is broken. It is flashing "Er" all of the first dive and won't show anything but time and depth. Upon downloading it to my laptop, I found out that she surfaced with deco time left at the end of the second day because she didn't know that she was supposed to kill it off (she thought that she had). Fortunately, she came out of it smelling like a rose and didn't get DCS (And did all six dives). I got a lesson about loaning out my dive computer without at least a quick briefing on "ASC" side of the fence as well as the "NDL" .

 

[WarmWaterDiver]

I understand both of my dive computers, and have read the manual(s) more than once. And, I take a copy of the manual with me, even on the boat. It's not hard to print a copy from the manufacturer's web site and place it in vinyl sheet protectors - I find this better than a 'cheat' card personally.

I understood the NDL tables, the math they're based on, and I understood the principles of the dive computers before I purchased them. In fact, I'd researched some before purchasing (more so on the second computer than the first, but enough each time for my purposes). Maybe I'm not 'typical' in this regard???