Suunto versus Aeris?

[FijiBound]

I believe Aeris was founded based on their computers. So I just assumed they were probably the best and most reliable in the industry. Now, however, I seem to be reading alot about Suunto computers. Any opinon here as to which computers are the most reliable, user friendly, best algorithms, etc? I'm not looking for something to push the limits, just want a better reading than the card can give me without getting me injured. Something reliable, sturdy, long-lasting is also ideal.

 

[BioNerd]

i have an aeris elite T3 and i love it. aeris, oceanic and sherwood are all the same computers. they are made by Pelagic. As for algorithm, they are less conservative than suunto. Suunto are the most conservative of all computers. that's not saying it's bad, just works on the safer side of things. If your looking for more hang time, go with the aeris, you'll be happy. However i hear the Uwatics can run circles around the aeris, oceanic and sherwood computers.

 

[Hoosier]

Each computer has their own pros and cons.

Sunnto: Durable, but conservative
Aeris: Liberal, but less durable

Just my 2 bar

 

[DiveMaven]

I love my Aeris AI and would buy one again if I were looking for a computer. When I did my initial computer search, the Suunto kept coming up, but I didn't like the high level of conservatism and much preferred to have control over how conservative I dive. The argument that it's "safer" doesn't fly with me since there is literally zero data to support that the risk of getting bent is less with a Suunto.

Although the Oceanic/Aeris line are more liberal, they still fall WELL within the NDLs of published tables.

 

[Charlie99]

Oceanic/Pelagic computers (including the Aeris) as well as most others are rather dumb devices that simply work as bookkeepers, keeping track of N2 loading in various halftime compartments. My Oceanic computer shows the same loading, and the same NDLs whether or not I'm doing reverse profiles, bouncing up and down, or popping to the surface at 120fpm. In other words, if you are misbehaving, its up to you to add in additional conservatism.

Suunto, OTOH, modifies the M-values (which in turn modifies NDLs) in response to reverse profiles, yo-yo diving, and ascent rates. These modified M-values reflect what you have done up to 100 hours ago.

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A feature difference that a lot of people overlook is that the Pelagic computers (Oceanic, Aeris, and others) have a bargraph that graphically displays the loading in the compartment closest to NDL, usually referred to a the Tissue Loading BarGraph or TLBG. Other computers with a bargraph simply repeat the NDL time info in a graphical format. Suunto calls it the Consumed Bottom Time or CBT bargraph.

The significance of this is that shallower than 25' or so, the Consumed Bottom Time or CBT bargraph will show that you have lots of time no matter how heavily loaded your tissues are. If you have not been paying attention to your profile and don't know from your own calculations how heavily loaded you are, you may falsely assume that you are very lightly loaded when only 1 or 2 bars near the bottom of CBT are displayed.

With the Oceanic/Pelagic computers, the TLBG will continue to show the loading level of the most heavily loaded tissue --- generally one in the 30-60 minute halftime and gives you a clearer indication of how heavily loaded you are. In other words, the TLBG gives you an indication which is more like a pressure group than NDL time remaining.

In this area, the Oceanic/Pelagic computers offer more and better info for you to use in planning your ascent and stops.

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If you are just going to more or less blindly follow your computer, then the Suunto algorithm is definitely better since it automatically adjusts for "bad behavior" on the part of the diver.

OTOH, the algorithm of the Suunto is not documented and the fudge factors are difficult to figure out. In addition, the bargraph being just a display of NDL (in other words, it will always go to green as soon as you go shallow) make it so that the Suunto doesn't give you a lot of feedback and assistance in making intelligent decisions.

The drawback of the Pelagic computers is that you can do a polaris-style ascent and they are completely happy with that. The Pelagic computers are more suited for someone who wants the computer to do the mechanical/rote/bookkeeping function of tracking compartment loading. You are responsible for adding in appropriate levels of conservatism for things like dehydration, cold, or bad profiles on the previous dives.

They are both good computers, but they have different sets of strengths and weaknesses.

Charlie Allen

 

[TravelSimone]

Wow Charlie,

Thanks. I really feel like I learned a lot here!

 

[Joe-Diver]

X2...I'm shopping for a computer and that was one of the most helpful writeups I've read so far..

 

[Rainer]

A feature difference that a lot of people overlook is that the Pelagic computers (Oceanic, Aeris, and others) have a bargraph that graphically displays the loading in the compartment closest to NDL, usually referred to a the Tissue Loading BarGraph or TLBG. Other computers with a bargraph simply repeat the NDL time info in a graphical format. Suunto calls it the Consumed Bottom Time or CBT bargraph.

The significance of this is that shallower than 25' or so, the Consumed Bottom Time or CBT bargraph will show that you have lots of time no matter how heavily loaded your tissues are. If you have not been paying attention to your profile and don't know from your own calculations how heavily loaded you are, you may falsely assume that you are very lightly loaded when only 1 or 2 bars near the bottom of CBT are displayed.

With the Oceanic/Pelagic computers, the TLBG will continue to show the loading level of the most heavily loaded tissue --- generally one in the 30-60 minute halftime and gives you a clearer indication of how heavily loaded you are. In other words, the TLBG gives you an indication which is more like a pressure group than NDL time remaining.

In this area, the Oceanic/Pelagic computers offer more and better info for you to use in planning your ascent and stops.

Um, sort of. That's only true if you run your Suunto in Air mode. Running in Nitrox mode (and setting to 21% when diving air), the bar graph shows oxygen tox exposure (Oxygen Limit Fraction). This is not the same thing as NDL.

Also, for those "concerned" about the conservatism of the Suuntos, on most of the dives I've done on my Vyper, at most I have a couple of minutes less time than my buddy (running a Dive Rite He). Not a big deal. The Suuntos are extremely reliable, and best of all, my Vyper (ditto for Gekkos and Vytecs) fit in the DeepSeaSupply wrist boots. Having a bungee mounted computer is both easier to don and doff, and is much more secure than traditional wrist bands (assuming you are running two bungees).

 

[Charlie99]

Um, sort of. That's only true if you run your Suunto in Air mode. Running in Nitrox mode (and setting to 21% when diving air), the bar graph shows oxygen tox exposure (Oxygen Limit Fraction). This is not the same thing as NDL.

Same problem, though. The Suunto doesn't give you good feedback on your N2 loading levels once you have gone shallow and are trying to make a decision on how long to hang out at 20' to 10' range. The Oceanic/Pelagic computers have separate bargraphs for O2 and N2 loading. There may be other computers (Uwatec ??) that have bargraphs that display relative N2 loading now that the Oceanic patent on the tissue-loading-bargraph have expired.

Also, for those "concerned" about the conservatism of the Suuntos, on most of the dives I've done on my Vyper, at most I have a couple of minutes less time than my buddy (running a Dive Rite He). Not a big deal.

Not at all a big deal if you get familiar enough with your Suunto that it doesn't confuse you when it switches over to the decompression mode. A decompression obligation isn't a problem. Having a decompression obligation and not having the gas to complete it is.

I've done several dives with buddies that went into deco on their Suunto computers while my Oceanic is up into the yellow zone, but hasn't swapped modes into the required decompression mode. My normal practice is to do an ascent and stops that get the Oceanic back to the green (or close to going back to green at least). In most cases, what it takes to get the Oceanic back to the green was pretty close to what it took to complete the "required" decompression obligation of the Suunto. In a couple cases, his Suunto wanted to do another 2 or 3 minutes of hang time to clear. No big deal.

If a Suunto is showing ridiculously short NDLs, there is generally a good reason for it.

It's kind of like an argument about whether a stick shift or automatic transmission is best in a car. Depends upon the situation and your preference. My car has an automatic. For the diving computer I prefer the "stick shift" version.

Of course, those that advocate using just a bottom timer or a watch and tables may claim that they are using the "stick shift" version. IMO, that's the horse and buggy version.

 

[Joe-Diver]

Horse and Buggy.....that would be no gauges and a J valve.....