Suunto Cobra

[markdj]

I just got a Citizen Cyber Aqualand NX and my dad uses a Suunto.

Doing 2 fairly shallow dives today and both were more conservative than the BSAC 1988 tables.

After 2 dives the Suunto gave 3 hours til fly, the Citizen (using Canadian algorithm) got 9 hours till fly, the PADI tables got 5hrs til fly and the BSAC tables got 12hrs til fly.

So is Suunto conservative? We were both together as buddies at all times.


M

 

[Vie]

The Canadian Defense and Civil Institute of Environmental Medicine (DCIEM) algorithm utilised by the Citizen Aqualand Nx “is unusual because it assumes only four tissues compartments and because it assumes that dissolved gas passers from your blood to your fastest tissue, and from it to the next fastest, and so on. Haldane and other theories assume gas passes from blood to each compartment directly,” according to John Francis, Training Editor of Scubalab. This makes the Citizen “very conservative at max. depths, but also very liberal during the later portions of ascents, sometimes even more liberal than Haldanean computers.” Most Suunto computers are NOT truly implementing the RGBM model. They are really dissolved gas, aka Haldanean, computers. Suuntos are conservative, but computers generally are more aggressive than using recreational dive tables.

 

[KrisB]

Having just compared my PADI table with the table given in the Suunto Cobra manual, it seems that the NDL used by Suunto is about halfway into the gray shaded area (i.e. what PADI calls a "Safety-Stop Required" dive). Since the computer is calculating the NDL based on the actual dive profile, rather than the max depth as you are supposed to with the table, it would seem to me that you can dive for longer with the Cobra than you can with tables alone...

HTH,

 

[vf84pc]

Do you still have the cobra? smapes444@yahoo.com

 

[vf84pc]

Still have the cobra smapes@harris.com?

 

[MildlyDamp]

I'd be willing to bet that using a Cobra has motivated more people to get Nitrox certified than any other reason. I've run out of no deco time with my Cobra a couple of times, although it was easy to clear it off by ascending a few feet. I think you might feel limited by it if you were on a liveaboard doing several dives a day. For one or two tank dive days, the conservativism isn't really an issue. The real question is does that match your diving style or not. If you like to push the envelope, don't get a Cobra. If you want to feel very safe, it's a great computer.

Overall, the controls, displays and functionality of the Cobra are good. The only negatives are its high price (especially if you pay full retail and get the PC interface) and the incredibly feeble and buggy PC software. If you do get one, get the quick disconnect; that's well worth the extra cost.

 

[Willar]

I used the Cobra on a Blackbeard's cruise where I dived at every opportunity, not skipping any dives. What I learned was that it seems you are penalized for down/up/down/up/down (jagged) profiles. Swimming a level profile and staying up a little seems to be best. If you are getting low on NDL time and acsend a few feet you can "earn" more NDL time.

Therefore, I learned to swim a safer profile. Not a bad thing, IMHO. My dive buddy or I ran out of air before hitting NDLs and I was never limited by the Cobra. For a recreational diver I think the Cobra is great. If you really like to push limits then a Cochran or another more liberal computer might be best. (Hmmmm, funny, I never did like liberals. LOL!)

 

[espenskogen]

Having just compared my PADI table with the table given in the Suunto Cobra manual, it seems that the NDL used by Suunto is about halfway into the gray shaded area (i.e. what PADI calls a "Safety-Stop Required" dive). Since the computer is calculating the NDL based on the actual dive profile, rather than the max depth as you are supposed to with the table, it would seem to me that you can dive for longer with the Cobra than you can with tables alone...

HTH,

That makes sense - As the gray shaded area of the padi tables are actually a 3 min required deco stop - On the suunto, at the point where the safety stop isn't optional, it becomes a deco stop with a 3 m ceiling.

If you want longer no-stop times than the suunto is offering, you're really just pushing the tables - Diving to the limit and all of that. In that case, I'd recommend to take a deco class, and just run up 5-10 minutes deco instead.

I've got a cobra myself, and I'm very happy with it. I wouldn't have minded so much if it had supported deep stops and a true RGBM model, but the conservatism on it suits me just fine. Doesn't mean I have to cut dives short - Just need to deco a bit longer - Which isn't a bad thing.

E