Inexpensive but not going to get me bent?

[Snowbear]

Nope. Not perfect at all. Yep. make mistakes all the time. Difference is, rather than relying on the computer to "tell" me when I'm "safe," I try to consistantly dive in such a way that my dives are far more conservative, yet with longer run times, than any computer will "allow."

The ego that relies on a computer to keep from being bent is more likely to get that hit than the ego that's been humbled enough to allow for learning how to avoid the hit.

I do like the option of being able to download the dive info from my Vyper to the PC. In guage mode, it doesn't show the theoretical tissue loading graph, but the dive profiles are a pretty cool feature.

 

[asaara]

In the PADI O/W course I just completed, the official stance was that the buddy team abide by the most conservative computer, or in the case of one buddy with a computer and one using tables, you'd default to the tables.

It would be best to communicate what your plan is before you hit the water - can't really "screw up" someone's dive plan if you've already agreed that coming up together at the most conservative value IS the plan!

That would be the best, yes, I was just mostly wondering about uncooperative/uncommunicative buddies that want more bottom time.

 

[Snowbear]

... I was just mostly wondering about uncooperative/uncommunicative buddies that want more bottom time.

Wow.... :11:

 

[asaara]

Now now asaara calm down..............

The point that we have been making is that no computer is gauranteed to not bend you.You seem to want a computer to replace your brain,which is not such a good idea. A computer is a great tool,just dont turn off the manual override/

No, I'm *not* looking for a computer to replace my brain, but for backup - I don't intend to turn my brain off entirely, but I would still like a *safe* backup. I'm not entirely sure where I ever said "I'm sick of thinking, I just want to throw away my tables and have the computer do all the work for me!". Kinda like making sure your octopus breathes well to start with, and that it's not always hanging around full of dirt and likely to not work when you really need it - doesn't mean you're going to be sucking on your Air2 most of the time! (those with your primary on a long hose, I don't mean you by this...)

 

[scubagirl15]

None of the computers will get you bent...if so, someone would have sued them out of business.

To me, the answer comes down to this:

- do you like the interface: ease of use is very important - what someone else finds easy to use and read may not work out that way for you

- cost of purchase

- cost of ownership: if something craps out on it, how much would it cost to fix if it's not a warranty-covered problem; if you need a new battery, do you have to pay to get it replaced at a licenced facility (online store or LDS) or is it user replaceable

- do you plan to dive EANx? if so, buy one now that is EANx capable.

 

[ianr33]

That would be the best, yes, I was just mostly wondering about uncooperative/uncommunicative buddies that want more bottom time.

Do you own a thumb? Thats what its for

 

[RocketMan]

A computer is pretty high up there on the list of Things I Need, thought I had a rough idea of what I was looking for, but now I'm getting confused by all the various levels of conservatism from different companies...

Take a look at a Genesis React Pro. It's an easy computer to use and has all the features you mentioned.

 

[tangfish]

Well first of all I can tell you that I have an Oceanic VT Pro and I've never gotten bent on the last 150 dives I've done on it. I don't like the Uwatec computers because they're ugly and a pain to use on the surface, but I've heard they're terrific underwater and there are no screens to scroll through. Suunto makes a good computer but they're overpriced and honestly, are you going to be doing all that dive logging on the computer? If the software is important to you then stay away from Oceanic. OceanLog software from Oceanic is probably the worst piece of software ever written (after Windows that is). I use a mac too and I'd say that putting virtual PC on your mac just to fiddle with your dive log is a bit like putting 4X4 wheels on a Ferrari so that you can drive down a gravel driveway at your friend's house.

Keep a hard-copy divelog and buy an Oceanic Veo computer from UWS.

A computer is pretty high up there on the list of Things I Need, thought I had a rough idea of what I was looking for, but now I'm getting confused by all the various levels of conservatism from different companies...

"Don't buy a Suunto!"
"Buy a Suunto, you won't get bent!"
"Scubatoys doesn't even *sell* Suunto!"
"*All* we sell is Suunto!"
"My grandmother is from Finland, talk Nokia, dive Suunto?"

Other than Oceanic seems to be the most likely to get you bent if you don't also remember what your tables said, and that you're more likely to go deaf than get bent diving a Suunto, where do the others (like the big grey chunky ones - Uwatec? - that seem extremely common in some places) fit in? How much less time do you get on a Suunto compared to tables, who here's gotten bent on an Oceanic?

I'm looking for a reasonably inexpensive non-air-integrated wrist computer that's relatively simple to read and operate, handles nitrox, that's reliable and isn't going to get me bent should the math cells in my brain take the day off. PC integration isn't a huge issue, since my main computer is a Mac, but I do have access to Windows machines if the ability to download data is really that amazing a feature to have (mostly looking for something to, strange as it may sound, use in the *water*...).

And am I on crack, or is the girl in the bikini on the beach in the 2006 Oceanic catalog actually running their software, advertised as Windows-only, on a Mac laptop??? How do they *do* that? That could be a factor in deciding, if something did run on a Mac...I used VirtualPC on another (not significantly older) Mac than my current one, and it hosed a bunch of my programs, uninstalling VPC and reinstalling the OS (not to a degree that it'd wipe my drive or system settings - wasn't willing to do that) didn't help...

 

[BlueDevil]

As I mentioned in another thread, I have never been able to find any data or study which shows higher incidence of DCS in recreational diving when using a computer with a liberal algorithm than with a conservative one. This was the deciding factor in my buying an aeris atmos rather than a TUSA IQ700 or gekko. (I don't need 2 gas capability) If there is such a study, I'd love to see it, actually maybe not since I've already bought my computer!

It is pretty remarkable how differently these computers can interpret off-gassing on certain profiles. But, if there really was a proven safety difference between the different algorithms, I certainly have a feeling we'd be hearing about it. I think a big part of the equation is the fact that we're talking about recreational, single tank diving within NDL limits. Planned deco dives, doubles, depth greater than typical recreational depths, that's a whole different story.

This seems a little strange to me! Because you have not been able to find a study that shows a higher incidence of DCS in recreational diving when using a computer with a liberal algorithm than with a conservative one you are therefore assuming that such an affect doesn't occur. Furthermore on this basis you have bought a computer that is often regarded as being less conservative than most others. Did it occur to you that the lack of such a study could simply be that no one has been bothered to do it, or someone wanted to do it but the data collection posed too much difficulty, or someone desperately wants to study this but can't get the funding etc, etc.??

Some very large differences are evident between computers. For example the NDL for 30m for one computer (Cyber Aqualand) is 14min and for another is 25min (Cochrane Commander). Now maybe no one has (yet) done a study which shows more people get bent using the NDLs on the Cochran as opposed to the Aqualand but simple logic would suggest that if "Group A" spent 11 min longer at 30m than "Group B" that the likelihood of DCS is most probably going to be higher in Group A than Group B.

A recently published article compared a variety of computers across five different series of dives. The differences where remarkable! In one series of repetitive dives the following results were obtained for the third dive:

Solution - 18 min deco
Vytec - 25 min deco
Aladdin Pro - 7 min deco
Aladdin Smart - 6 min deco
Oceanic Versa - 0 min deco
Cochran Commander - 0 min deco
Cyber Aqualand - 9 min deco

The differences between these computers are huge! Imagine a buddy pair using a Vytec and a Versa. For one diver this is a no deco dive, for the other buddy this is a 25 min deco dive!!!! The trouble is we don't know which computer is "correct". Maybe the Versa is quite safe and the Vytec ridiculously conservative. But if we assumed the Vytec to be "correct" then the Versa user may be in for big trouble! Further to that this series of dives would be regarded as "recreational" if we went by the Versa or Commander, but would be a "technical" dive (ie deco ceiling) according to all the other computers in the study.

Interestingly this difference in conservatism was not consistent across all the different dive series tested. Of the five different dive series the Oceanic came out as one of the least conservative computers for four of the dive series. However in the fifth series of dives (cyclic bounce dives - 3 x dives to 45m with 5 min BT and 60 min SI)the Versa was by far the most conservative. Most computers required no decompression, the Vytec required 2 min deco, and the Versa required a whopping 28 min!!!! (Unfortunately the Oceanic was only more conservative than the others on a series of dives that the average diver is never likely to do!)

What can we make of all this?? Personally I would tend towards the more conservative computers, that is my nature. Even the most conservative computers will give you significantly longer bottom times for multi-level dives than you would ever get from a set of tables. However a computer that is conservative in one circumstance may not be so in another circumstance. Given that many of the computers on the market use an underlying Buhlmann algorithm it would seem that the implemetation of that algorithm in different computers is vastly different (though the Suuntos are using RGBM if I remember correctly). My advice would be to always dive your computer conservatively, and add in plenty of safety stop time, particularly if yours is one that tends to be fairly 'liberal'.

 

[halocline]

Yeah, I saw a few comparisons that really showed a big difference on some profiles. In particular, the haldanean computers (aeris, oceanic) really give credit for ascending; I've been near the end of a dive that maxed at maybe 90ft, then gradually worked shallower, and seen over an hour of NDL showing on my atmos. (but stilled showed significant N2 load in the N2 bar, maybe just out of the yellow) At that point in the dive, my buddy with a suunto showed just a few minutes...they're probably not both right! But, remember this is near the end of a single tank dive, when gas supply is low and I'm heading up anyway.

The sort of argument that you present is what almost pushed me to get a more conservative computer. The thing that kept me from doing so, though, is the fact that thousands of divers have used the haldanean computers on many thousands of NDL dives, and I feel pretty certain that if there was some inherent safety issue with the computers on this type of dive, single tank (usually AL80) at recreational depths, someone would have said something about it; there's simply too much liability at stake. The key here is the type of usage; single tank, recreational depth, sensible profiles. I would venture a guess, and this is just a guess, that almost all DCS incidents (about 1 in 23,000 according to stats I've read) in this type of diving are due to diver error; most likely dehydration, rapid ascent rate, possibly heavy exertion immediately after diving. This would be the only explanation I could think of that would account for a lack of corrolation between computer algorithm and DCS in recreational diving. With that in mind, I bought the atmos, as I really like the interface, reputation for reliability, and the price was right.

When/if I get into deep and/or multi tank diving with planned deco, I'll get a computer specificially designed for that usage. Or, if the training I get for that specifies, bottom timer/tables. At the moment it's not on the horizon for me, so my computer is strictly recreational in design.

I agree totally with the idea of adding safety stop time; in fact, it's my understanding that for most computers, the initial required deco stop when crossing the NDL line would be shallow, much like our typical safety stop. I usually hang at 15 feet for a few extra minutes, then a few minutes at 10 feet as gas supply allows. What's the rush getting out of the water anyway?