Can Suunto Cobra 2 be used for deco diving?

[rstofer]

Well! That's about as clear as it gets!

From the Nitek Duo manual (no, I'm not selling computers!):

The NiTek Duo dive computer is a multifunctional computer for
recreational diving, providing information on depth, dive times,
no-decompression and decompression times, and nitrogen and
oxygen absorption and elimination during all dive phases,
including ascent, surface interval times, and subsequent dives.

The NiTek Duo can calculate decompression stop
requirements for stops as deep as 90 feet (27 meters)

Although the NiTek Duo is capable of calculating
decompression stop requirements, users must remember that
dives requiring mandatory stage decompression carry
substantially greater risk than dives made well within nodecompression
limits.

Richard

 

[cvigue]

.... overall, I don't think you'd need to throw it out. However, if you're paying $700 for that thing, you're overpaying. By a lot.

I was looking at leisurepro.com and they want $600 for the Cobra 2 now; when I started looking it was $650 and I would want a new retractor for it.

I'm open to other options, for instance this uWatec Console looks like it might be comparable.

$600-$700 represents a good chunk of a days work for me and I want to spend it on something that I'll use for a while.

 

[NudeDiver]

I was looking at leisurepro.com and they want $600 for the Cobra 2 now; when I started looking it was $650

Yeah, it's amazine how the prices on this stuff drop. It's why getting something used can save you a lot of money

I would want a new retractor for it.

Seems like an odd configuration. I can tell you from experience using a cobra that a retractor isn't really necessary. Just having it clipped off to a d-ring on the front of the BC provides plenty of opportunity to view it while diving. If you actually needed to use the compass for something (assuming you want a console compass to begin with), unclipping it and using it is really a piece of cake. I'm now using a simple bolt-snap attached to the unit via a small ziptie. Works great - way cheaper and less prone to issues than a retractor. On that note - I used to use a console compass, but I reconfigured to a wrist mount one.

$600-$700 represents a good chunk of a days work for me and I want to spend it on something that I'll use for a while.

FWIW, I paid about $470 for my Cobra with compass and quick disconnect, and I'm still using it 5+ years later. I don't see replacing it with something more advanced any time soon.

 

[AzAtty]

Since every dive is a decompression dive, a Cobra will handle a decompression dive of the "no stop" variety just fine. However, dives requiring decompression stops are another matter.

I do have experience with staged decompression diving and Suuntos. Here are the simple steps to follow for a staged deco dive on a Suunto:

1. Custom cut your tables on D-Planner or V-Planner or the U.S. Navy tables (or other software/tables).
2. Put the Suunto in gauge mode.
3. Follow your dive plan using the Suunto to determine depth and time.
4. Enjoy the dive.

Although that is somewhat tongue-in-cheek, I believe it's sound advice. Suunto Vypers and Cobras don't like it much when you go below 130 feet, at least in computer mode. The alarm chirping get annoying.

I don't like how Vypers and Cobras handle decompression. They get those pesky little bubbles in their eyes. They don't allow for deep stops (penalize them, as a matter of fact). They don't allow for gas switches. As the manufacturer candidly states, they're not for decompression diving, and I would NOT count on Sunnto's recreational (i.e. NO DECO STOP) version of the RGBM algorithm to carry you through serious deco dives. If you're serious about decompression diving on a computer, take a course that will teach you how decompression theory and procedures, and get a computer designed to handle the stuff you will throw at it during a real staged deco dive (VR3s are nifty). Or, buy decompression software and a wrist mounted gauge/bottom timer. Still, take the class.

 

[Kern]

According to the old Navy tables, you could dive 300' 40 minutes and not need a 90' stop. Not that I'll ever find out!

But the Nitek Duo doesn't handle trimix or any of the exotic blends most often used in deco diving. Air and Nitrox, that's it.

If you really want to go nuts with deco diving, there are very few choices in computers. In fact, I would guess that almost everybody who has been trained for this type of diving has a written plan and just uses 2 computers in gauge mode.

Richard

Sorry, but if anyone is diving air or nitrox to 300ft for 40 minutes they are insane. High ppO₂ & CNS is just the beginning of their problems. Then there is the gas logistics, task loading & narcosis on top of their initial mental instability.

 

[rstofer]

Sorry, but if anyone is diving air or nitrox to 300ft for 40 minutes they are insane. High ppO₂ & CNS is just the beginning of their problems then there is the gas logistics, task loading & narcosis on top of their initial mental instability.

I absolutely agree!

But the figures are straight out of the 1968 edition of "The New Science of Skin and Scuba Diving" Table 1-9 U.S. Navy Standard Air Decompression Table for Exceptional Exposures page 214

Even Table 1-5 U.S. Navy Standard Air Decompression Table goes to 190 feet - page 210.

As I said, I will never find out if they work!

Richard

 

[cvigue]

So in the market of console style recreational dive computers with air integration it seems like the consensus is that Suunto Cobra 3 (or 2) is OK. Here are the features I liked:

• User replaceable battery
• Easy to understand and read display
• Computer interface available
• Quick disconnect
• Nitrox capable

Any other contenders I should consider? Anything that would be more capable later and easy to use now for under $1500 or so?

 

[NudeDiver]

So in the market of console style recreational dive computers with air integration it seems like the consensus is that Suunto Cobra 3 (or 2) is OK. Here are the features I liked:

• User replaceable battery
• Easy to understand and read display
• Computer interface available
• Quick disconnect
• Nitrox capable

Any other contenders I should consider?

Also, don't forget about the Cobra 1. It has all of those features as well, and will probably be cheaper for you to obtain than other of those.

FWIW, I think the menu system on the cobra sucks. I find it strongly non-intuitive.

Also, the USB cable to connect to a computer is about $100. Something to keep in mind. The software that comes with it also doesn't work on a Mac, but free software to do this is available from other sources, if that is a feature you need.

 

[Dtaine]

Here's the thing. I DID plan to go into deco. Based on the characteristics of my computer, and of those used by others on the boat, I KNEW I would be going into deco. It was not anything inadvertent or for lack of attention. It appears that our difference of opinion relates to the length of time in deco, not whether one can do deco dives on a Cobra, without heading for a chamber ride.

If these dives could truly be done without a mandatory deco obligation, then why wouldn't you just put the computer into gauge mode?

You were saying that you planned to go into deco, but in reality you were just following a computer that gave you an unnecessary obligation. That's not really planning a deco dive.

I don't get the point of using a computer if you know it's mandating unnecessary decompression stops. What was the profile on these dives?

 

[Slonda828]

So in the market of console style recreational dive computers with air integration it seems like the consensus is that Suunto Cobra 3 (or 2) is OK. Here are the features I liked:

• User replaceable battery
• Easy to understand and read display
• Computer interface available
• Quick disconnect
• Nitrox capable

Any other contenders I should consider? Anything that would be more capable later and easy to use now for under $1500 or so?

All of the cobras are pretty good IMO. I still use a regular old cobra and it works great. I have it on a 22" hose with a snap link. It's like an SPG that does a whole lot more. It has the same amount of O-rings as a regular SPG, and in my experience using it for a long time it's never failed me once. It's only for recreational diving, but that's all I do. It has nitrox too, which is nice. Bear in mind that the quick disconnect adds like 4 extra O-rings to leak. I have a QD, but I took it out and now it sits in my closet.