Can Suunto Cobra 2 be used for deco diving?

[pt40fathoms]

I'd love to see any evidence that supports this statement.

No, you most likely don't. However I have sent a note to Suunto and when I get a response in the next 24 to 48 hours, I'll post it here.

It seems that some people need to be reminded that diving in to deco requires more than just a computer to tell them what to do.

 

[Colliam7]

I'm considering a Cobra 2 since I liked the Cobra so much. ... One thing I'm concerned wit is that a friend has mentioned this comp is not a full deco unit like some of the Aeris and other units. ... So I guess in a nutshell what I want to know is at what point of dive expertise is this comp going to become inappropriate and need replaced?

It is perfectly functional for virtually all recreational diving. While it might be used during decompression diving, where you are using backgas, or only one other gas (e.g. 50% or 100% O2) for deco, it is not designed for 'serious' decompression dive planning / simulation. But, as several have said, in those circumstances, many divers put their computer in gauge mode (which you can do with the Cobra 2), and dive according to the tables they have already prepared with whatever decompression software they are using. So, it would not necessarily need to be replaced even at that point. Where you might want to add a second computer, would be the point where you start to use helium mixes. I dive a Vytec during decompression dives where I am using only air, and enriched air or 100% O2, and find it perfectly functional. It has the capacity for 3 gases, which I personally find useful. But I use it as an adjunct / back-up to my tables, not as a planning instrument.

 

[NudeDiver]

No, you most likely don't. However I have sent a note to Suunto and when I get a response in the next 24 to 48 hours, I'll post it here.

I'll bet a nickle that they don't state that if you happen to go a little into deco mode a few times in a span of a weekend that it is not a certainty that you will need to go to a chamber.

 

[MMM]

If you do dive the computer and go into deco several times during the course of a dive weekend or trip, you will almost certainly enjoy a ride in a chamber.

I had (repeat HAD) a Suunto Cobra that would regularly go into deco long before other divers in our group using different computers. (We're talking a few minutes here - maybe 10 minutes tops.) I used it for several years on long trips. Never had a chamber ride. Sometimes it would clear during a slow ascent and sometimes I had to hang at 15-20 feet longer than other divers in the group who had dived identical profiles.

Have a different computer now - still diving same profiles, w/o deco obligations. How does that change anything? With all due respect, I'm with nudediver on this one.

 

[pt40fathoms]

I'll bet a nickle that they don't state that if you happen to go a little into deco mode a few times in a span of a weekend that it is not a certainty that you will need to go to a chamber.

Here is what I said:
"The Suunto line of computers will get you out of the water if you inadvertently venture into a deco situation by not paying attention during your dive. But it is NOT designed for planned deco diving in any way. If you do dive the computer and go into deco several times during the course of a dive weekend or trip, you will almost certainly enjoy a ride in a chamber."

Now you are saying "if you happen to go a little into deco mode a few times in a span of a weekend". Well, you just agreed with me, and you may not have even known it!

Their is a big leap from "a little into deco mode", and planning a dive that will take you into the realm of hanging on a line at various depths for 1 to 15 minutes or longer. At the risk of sounding like I am repeating myself, I'll once again point out that I said "The Suunto line of computers will get you out of the water if you inadvertently venture into a deco situation by not paying attention during your dive."

But must reinforce the point that you should NOT use it for planned repetitive dives into deco. I'm not talking about a minute or two that usually clears during a slow ascent, I'm talking about planning to hang around at various depths to off gas after a planned deco dive. For this you must seek training, which will prepare you to plan properly. This may include putting the Cobra2 into gauge mode and have a set of bail out tables on hand, as well as using a multi-gas computer if you are going to deco on Nitrox or O2, and so on.

Do you see the difference?

 

[NudeDiver]

Do you see the difference?

The difference I see is you engaging in a little creative revisionism. In case you missed it, you said:

If you do dive the computer and go into deco several times during the course of a dive weekend or trip, you will almost certainly enjoy a ride in a chamber.

And this is what I and others have disagreed with, and are still waiting on you to provide any supporting evidence whatsoever that the above statement is true. I might add that this may be especially difficult, since some of us may have gone "into deco several times during the course of a dive weekend or trip" and found that a ride in a chamber was anything but being "almost certain."

 

[MMM]

Here is what I said:
"The Suunto line of computers will get you out of the water if you inadvertently venture into a deco situation by not paying attention during your dive. But it is NOT designed for planned deco diving in any way.

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.

 

[Reg Braithwaite]

So are the people with actual decompression diving experience lining up to say that it is reasonable to use a Cobra 2 to plan and execute decompression dives? Or are you lining up to say that it is risky to plan and execute decompression dives with a Cobra 2, and that its management of decompression stops is best used as a safety feature for when a planned no-decompression dive ends up being deeper or longer than intended?

Just looking for some consensus here.

 

[rstofer]

If the Suunto can handle 300' for 50 minutes, it is probably a deco computer. If not, well, maybe it isn't.

I have spent a bunch of time reading the instruction manuals for various computers. I NEVER intend to do deco diving but I wanted a computer that was capable. One thing I found in my reading is that many computers do not know how to handle deep deco stops. Some can handle deco stops to just 60' or some other arbitrary depth. In fact, some give up in disgust part way through the dive and give some kind of error message like 'Error' or 'Use Tables'. This is not the kind of thing I want to see. I want a computer that will stick with me!

So, read the manual carefully. See what it actually says about deco diving. I think you will be amazed at how badly some computers handle intentional deco dives. I'm not talking about those 'oops' dives but rather those dives where deco stops are required at depths below some arbitrary depth, say 60'.

If you really want to do it right, consider the LiquiVision X1. What a magnificent computer!

No, I don't own one. I have the Dive Rite Nitek Duo. It will meet my needs quite well.

Richard

 

[MMM]

If the Suunto can handle 300' for 50 minutes, it is probably a deco computer. If not, well, maybe it isn't.

Using that definition, then no it cannot. My Cobra (admittedly not a Cobra 2 but probably not significantly different outside of the integrated compass), could not handle multiple tanks of different gases. I understand that my new Galileo can though I haven't tried it out for that purpose. (Still trying to get it to work on a single tank with air...)