Atomic Aquatics Cobalt Dive Computer

[Mud Guppy]

Yes, I agree max depth is very important for a table diver especially in repetitive dives. But as we all know the tables do not average your dive hence no credit for depth not used. With us computer divers I think we pay less attention to max depth and more to psi, no deco time and dive time remaining. In my computer I set alarm for the max depth I wish to go but depth average is of little concern. However if the average dive time is in memory with all relevant dive data to be uploaded into the PC and the dive can be graphed that would be real sweet.

 

[RonR]

Yes, I agree max depth is very important for a table diver especially in repetitive dives. But as we all know the tables do not average your dive hence no credit for depth not used. With us computer divers I think we pay less attention to max depth and more to psi, no deco time and dive time remaining. In my computer I set alarm for the max depth I wish to go but depth average is of little concern. However if the average dive time is in memory with all relevant dive data to be uploaded into the PC and the dive can be graphed that would be real sweet.

Sounds like we're on the right path showing max depth during a dive.

We calculate average depth essentially continuously during the dive, and save it with the dive data at whatever sample storage frequency the user has selected. At the moment it's not being displayed with each dive segment in the dive log- that is, when you step through the actual dive log graphic profile display on the Cobalt Cobalt Guide: Dive Log: Dive Profile . We display Depth, Time, Gas Pressure, Gas Mix, Temperature, NDT remaining, and "Status", which means any violations or "events" like a gas switch or calculating a deco schedule. On the desktop software, of course it's a lot easier to display more data, since there is a lot more room on a computer desktop than on the Cobalt's screen.

Thanks for the input.

 

[pentae]

This looks awesome, but the 12 month warranty (only activated by sending in a warranty registration) is a real concern to me.. 1st generation products are usually always buggy, it is suspicious that Atomic are not honoring more than a minimum warranty period, the Oceanic OC1 comes with a 5 year.

 

[Thaney423]

I just received my cobalt and logged 4 dives this weekend I like the computer alot but I have a few comments and questions!? I think I read that the divelog software will be availible on the Atomic Aquatics web site soon so thats that question answered. I would also like to see the average depth but not on the main screen more in the log, the log program I use on my iPhone uses average depth to calculate air usage rate. I would also like to see the surface time between repetitive dives in the log, I don't log my dives till I get home and since there is no surface time listed I have to go back and figure it out by dive times. One of my concerns is the model used for the dive time I compared the planning feature with my Cressi Archimedes and my dive buddies computers and the time listed by the cobalt are almost double what's listed by the other computers untill you reach 80 or so feet where the times are a minute less than other computers. After the weekend and wondering about this I used the simulation mode to run a couple mock dives and check repetitive dive time, after a dive the ndl's show pretty high but changing the start dive in field to one minute later the times dropped. I am assuming this is because starting at 0:00 it's assuming you are still in the water but this is very deceiving. As if right now I will not dive this computer alone I don't trust the NDL times untill I hear an explanation. The last thing is the no fly time shown, not that I really use this as I don't really travel but it is strange, after my first dive on Saturday to 130 feet a 22 min dive the no fly time shown was 12 hours yet after a 80 foot dive not consecutive for 35 mins the no fly time shows 24 hours. These are things that I noticed with this computer I love the computer and will be really happy once I can ditch my wrist mounted computer maybe I don't understand what the computer is telling me but I have not ever had to question my Cressi. I look forward to any information I hear back.

 

[RonR]

This looks awesome, but the 12 month warranty (only activated by sending in a warranty registration) is a real concern to me.. 1st generation products are usually always buggy, it is suspicious that Atomic are not honoring more than a minimum warranty period, the Oceanic OC1 comes with a 5 year.

Atomic's Cobalt warranty is actually two years if you register the warranty, one year if you don't- as an inducement to register the product. While it is new to the market, the Cobalt has been around for a few years in testing.

 

[Thaney423]

Has anyone noticed strange NDL times when checking the planning feature after dive?

 

[RonR]

I just received my cobalt and logged 4 dives this weekend I like the computer alot but I have a few comments and questions!?

I'll try to respond to your questions below:

I think I read that the divelog software will be availible on the Atomic Aquatics web site soon so thats that question answered. I would also like to see the average depth but not on the main screen more in the log, the log program I use on my iPhone uses average depth to calculate air usage rate.

This is what we have been hearing from others, average depth in the log. We will look at including this in the next firmware update.

I would also like to see the surface time between repetitive dives in the log, I don't log my dives till I get home and since there is no surface time listed I have to go back and figure it out by dive times.

This is another request we have heard, and in fact the next firmware update, currently beta testing, does display for every dive in the log the surface time between it and the previous dive, if it was less than 99 hours. The most recent dive displays the surface time to the current time, only if it is less than 24 hours.

One of my concerns is the model used for the dive time I compared the planning feature with my Cressi Archimedes and my dive buddies computers and the time listed by the cobalt are almost double what's listed by the other computers untill you reach 80 or so feet where the times are a minute less than other computers.

This is a little hard to answer without specifics. Were you comparing air or EAN times? What conservatism levels were chosen for the various computers? What specific depths and settings were producing double the no stop times on the Cobalt, compared to other computers? Almost double seems an excessive difference. How do the no stop times on the other computers compare to times given in tables or by dive software for various algorithms? That is to say, the Cobalt gives (at my conservatism and age settings) 53 minutes no-stop time on air at 60' with 1000 mbar atmospheric pressure, and no previous dives. That's pretty much what tables and most other computers would give (NAUI/ PADI tables = 55 minutes). The Cobalt is fairly middle of the pack compared to other computers when it comes to no-stop times, neither the most liberal or the most conservative in our testing. It does, however, let you set some variables that will alter no stop times. The age you have entered, the risk level and the exertion level all influence the conservatism of the algorithm. Repetitive or multi-day diving are accounted for in the algorithm and definitely affect the no stop times.
The Cobalt also uses an absolute pressure sensor, so no stop times at altitude (or during storms!) will reflect the lower atmospheric pressure.

After the weekend and wondering about this I used the simulation mode to run a couple mock dives and check repetitive dive time, after a dive the ndl's show pretty high but changing the start dive in field to one minute later the times dropped. I am assuming this is because starting at 0:00 it's assuming you are still in the water but this is very deceiving. As if right now I will not dive this computer alone I don't trust the NDL times untill I hear an explanation.

I'm not sure I'm understanding the question- looking at no stop times after a simulated dive (or a real one, for that matter) your no stop times would be shortest right after the dive, with zero surface interval. As you increase your surface interval, your no stop times will increase. How rapidly they increase will depend on the tissues involved- short dives that primarily affect fast tissues will clear most rapidly, longer or multiple dives will affect slower tissues more and will clear more slowly. For most dives, the first 20 minutes or so of surface interval changes the no stop times a lot, and even a minute or two has a discernible effect. Note that the simulator, unless you tell it differently, will be basing calculations on your current saturation and current atmospheric pressure. I apologize if I'm not answering the right question- maybe you could give an example?

The last thing is the no fly time shown, not that I really use this as I don't really travel but it is strange, after my first dive on Saturday to 130 feet a 22 min dive the no fly time shown was 12 hours yet after a 80 foot dive not consecutive for 35 mins the no fly time shows 24 hours. These are things that I noticed with this computer I love the computer and will be really happy once I can ditch my wrist mounted computer maybe I don't understand what the computer is telling me but I have not ever had to question my Cressi. I look forward to any information I hear back.

This I can answer. The Cobalt follows the DAN recommendations for no-fly times. A single no-deco dive is 12 hours, a second dive in the same 24 hour period will generate a 24 hour recommended no-fly time, regardless of depth.
Thanks for the comments- I hope I helped.

 

[Thaney423]

I appriciate the answers, I was diving with two mixes for a deep dive class and did switch my mix to a Nitrox pony bottle at the 15ft safety stop and am not sure the other students switched their computers and thought that this might be the reason for the difference. We made two dives one for 130 fsw for 22 mins where I switched gas at safety stop then a second dive 2:07 mins later to 84 fsw for 22 mins where I also switched gas at the safety stop. When we returned to the classroom 3 hours or so later we all compared no stop time using the planning feature and at 40 feet my cobalt showed having a no stop time of 120 mins at 40 feet while the others had ranges of 70 to 80 mins. My settings were moderate risk and exertion levels. I was hoping that by switching gas I had gained that time but I don't see that big of a difference being right! As for the simulations I just ran a simulation as fallows:

Straight to 75 feet for 10 mins then right to 15 feet for 3 mins then right to zero for one min.
Now when I go to that profile and "view nst" with 0 hours 0 min in the "start dive in" box I show 84 mins nst at 40 feet by changing the "start dive in" box to 0 hrs 10 mins I get a new time at 40 feet of 79 mins.

Unless I'm completely wrong, forgive me if I am, I would think starting the dive 10 mins later should result in a longer nst as I have had 10 mins of off gas?

These are the best examples I can give at this point I will be in the water again on wednesday and will be on straight air and will compare with my old computer for testing. Again thanks for the quick reply.

 

[RonR]

I appriciate the answers, I was diving with two mixes for a deep dive class and did switch my mix to a Nitrox pony bottle at the 15ft safety stop and am not sure the other students switched their computers and thought that this might be the reason for the difference. We made two dives one for 130 fsw for 22 mins where I switched gas at safety stop then a second dive 2:07 mins later to 84 fsw for 22 mins where I also switched gas at the safety stop. When we returned to the classroom 3 hours or so later we all compared no stop time using the planning feature and at 40 feet my cobalt showed having a no stop time of 120 mins at 40 feet while the others had ranges of 70 to 80 mins. My settings were moderate risk and exertion levels. I was hoping that by switching gas I had gained that time but I don't see that big of a difference being right!

I can't duplicate the dive in a simulation without knowing what your mix(s) were ( I assume the 130' dive was not air?- that would have been well into a deco schedule) or what your deco mix/ safety stop times were. However if you duplicate the profile in the simulator on the Cobalt both with and without the gas switch, put in the surface interval, and check the comparative no stop times I expect you will see that switching to a EAN mix at the safety stop makes a pretty big difference. If your classmates did not switch their computers or were not all using the same mix settings it's not at all surprising to see those kinds of differences, particularly after two dives, and taking into account that some computers are a lot more conservative. If you were looking at NST's based on an EAN mix, were the others as well? Some computers default back to air without telling you.
You could also "step through" the dive profiles in the Cobalt dive log, and look at what your mix/ no stop times were at each stage of the dive. If you want to send me a detailed profile I'd be happy to run it for you.

As for the simulations I just ran a simulation as fallows:

Straight to 75 feet for 10 mins then right to 15 feet for 3 mins then right to zero for one min.
Now when I go to that profile and "view nst" with 0 hours 0 min in the "start dive in" box I show 84 mins nst at 40 feet by changing the "start dive in" box to 0 hrs 10 mins I get a new time at 40 feet of 79 mins.

Unless I'm completely wrong, forgive me if I am, I would think starting the dive 10 mins later should result in a longer nst as I have had 10 mins of off gas?

These are the best examples I can give at this point I will be in the water again on wednesday and will be on straight air and will compare with my old computer for testing. Again thanks for the quick reply.

You have (very astutely) uncovered a somewhat counterintuitive aspect of the simulator. What you are seeing in the profile you describe is the repetitive dive penalty coming into play. At zero surface interval the simulator sees it as a continuation of the previous dive, and you don't get the penalty. As soon as you add surface time, the repetitive penalty kicks in, and you will see the no stop times in the shallow zone decrease (compared to a zero surface interval) until about 30 -40 minutes have passed, when they will start to go up. Deeper depths will hold steady or increase with time as you would expect, but it's not a linear function. It does depend somewhat on which tissues are limiting.
This wouldn't occur in real dives, because the dive wouldn't "end" until you had at least two minutes of surface time, so in real dives you will always see the repetitive penalty.
We could probably avoid this potential question by putting in a default surface interval of at least a couple of minutes after finishing a simulated dive, so we always present the repetitive penalty. I'm putting that on our list.

Thanks for your comments, this kind of detailed feedback really helps us to design a better computer.

 

[Downing]

Another vote for maximum depth rather than average depth displayed during the dive.

Thanks for passing on the feedback about a protective cover. I share Mudguppy's sentiments: shame, shame on Atomic.

Hey, at least I didn't say, "A pox on both your houses."

Seriously, the Cobalt is one beautiful and expensive piece of gear, and I'm surprised no one at Atomic thought to come up with some sort of branded cover. This thing was in production for years, after all. Plenty of time to come up with something. Very strange coming from the same company that included the nicest reg bag I've ever seen when I purchased their flagship regulator.

Sure I can put it in a Leisure Pro house brand or XS Scuba bag or even an old sock. Just strikes me as wrong. The Cobalt deserves its own cover.

Alright, enough with the whining. Thanks again for passing it on.