Deco Diving - Computer Help Needed (Cobra 3, or others!)

[dumpsterDiver]

So, based on the screen of the Cobra 3, if I accidentally enter deco mode and I am at 75 feet, and the computer displays a ceiling of 30 feet, and an ascent time of 10 minutes, and if it takes me two minutes to reach the ceiling of 30 feet, and my ascent time now says 8 minutes (because I just traveled up for two minutes), does that now mean that I have to stay at this ceiling of 30 feet for the 8 minutes (meaning that my ascent time becomes, or equals, my deco countdown time to stay at the ceiling for decompresion)?

Sorta.. the computer would also count the time from the last deco stop to the surface.

 

[ianr33]

O.K. Few Things.

First off, not sure how anyone would ever "accidentally" enter deco and I'm not familiar with the Cobra 3. However.............

When you first "accidentally" go into deco the initial stop depth will be at 10 feet. (Could be deeper with a computer such as the Shearwater Predator that runs Buhlmann with gradient factors, but I doubt the cobra does that)

If your average recreational computer shows a deco stop required at 30 feet then you are seriously screwed!!!!!!!! My Aeris computer probably needs 20 minutes at 150 feet before it even needs a 20 foot stop.

However, if the computer were to display an ascent time of ,say, 8 minutes when you are at 75 feet it should also indicate ,say, 1 minute at 30 feet deco stop.
If you took 2 minutes getting to 30 feet then it may start adding on deco as you are ascending too slowly. Lets say by the time you get to 30 feet it says Total Time to Surface (TTS) 8 minutes and a 30 foot stop for 1 minute.
After 1 minute the 30 foot stop will clear and it might say 20 feet for 2 minutes.
After 2minutes at 20 feet that will clear and it would say 5 minutes at 10 feet. After another 5 minutes it will clear deco provided you are at 10 feet. Stay deeper and it will take longer

Make Sense??

If you try this without really knowing what you are doing, you have a great chance of either getting bent or drowning, so don't do it!!!!

 

[DitrasetMan]

Got it. Thanks.


I still am trying to find out the answer to my second question above, regarding, specifically, the Cobra 3. Does it, or does it not, display the time remaining at each deco stop or does it only show the total ascent time (which implicitly includes the time at all deco stop).

 

[DiveNav]

.... if I accidentally enter deco mode and I am at 75 feet, and the computer displays a ceiling of 30 feet, and an ascent time of 10 minutes, .....

This scenario (a TAT of 10 minutes at 75ft) is a bit more than just an "acccidental" deco.

.....I am at 75 feet, and the computer displays a ceiling of 30 feet, and an ascent time of 10 minutes, and if it takes me two minutes to reach the ceiling of 30 feet, and my ascent time now says 8 minutes (because I just traveled up for two minutes),.....

That is not guarantee. It could infact happen that while you are ascending the TAT number could change drammatically (reduced) and you could even exit from DECO before you get to the deco stop.

Lastly, as far as I remember ..... the Cobra 3 does NOT display the deco stop time. But it uses several symbols (up/down arrows) to tell you what to do.

Load the Cobra 3 in divePAL and take it for a Deco dive

​

Alberto (aka eDiver)

 

[Mr Carcharodon]

Someone has to know this...

You "asc" ascent time is the time to get out of deco and back into an no deco mode. Paradoxically you will still have a safety stop to do where you will decompress even more after you are done with "deco". Assuming you just run over by a few minutes there will likely only be one stop to do in any case. Suunto RGBM has 5 types of penalties that it tacks on that make dive and gas planning next to impossible. The end result is very conservative which is all well an good if you have the gas to do the unpredictable deco and your dive buddies don't bolt at the ludicrous plan your computer is calling for. Or at least they will think your plan is ludicrous by looking at their computers.

 

[DiveNav]

....If your average recreational computer shows a deco stop required at 30 feet then you are seriously screwed!!!!!!!!

I second that!

....If you try this without really knowing what you are doing, you have a great chance of either getting bent or drowning, so don't do it!!!!

Unless you do it virtually

 

[Centrals]

I still am trying to find out the answer to my second question above, regarding, specifically, the Cobra 3. Does it, or does it not, display the time remaining at each deco stop or does it only show the total ascent time (which implicitly includes the time at all deco stop).

ianr33 had explained very well on his last post(#12).
1. The computer will only show the total time required for you to surface and the depth of your first deco stop from your present position.
2. It will not tell you any more until you have reached the "required" depth.
3. If your ascent is slow then you will be penalized(more deco time added).
4. Complete the required stop as indicated by your computer and follow its next instruction.
5. Take one step at a time.

 

[DitrasetMan]

Lastly, as far as I remember ..... the Cobra 3 does NOT display the deco stop time. But it uses several symbols (up/down arrows) to tell you what to do.


Alberto (aka eDiver)

By the way the 75 foot depth and 10 minute figures were ones that I pulled out of the air, I was just trying to understand the process in the event deco unintentionally occurs.

So, based on DivePal (which I have been using) and Alberto: when you enter deco mode, the remaining air time which is displayed on the left is replaced with the ceiling, which I need to go up to. And, the no deco time on the right is replaced with total ascent time. There is no specific deco countdown when you arrive at each deco stop.

Another question, assuming I have only one deco stop: does the Cobra 3 display the total ascent time from where you are until you reach the surface, or where you are until you have traveled up to the ceiling and completed your deco time? (you all are conflicting on this point). Does it incorporate the amount of time that will be necessary to stay at the mandatory safety stop? I understand what the arrows are telling you (up means go up to the ceiling, up and down mean stay where you are, and down arrow with "Er" means that you went above your ceiling and need to go beneath it immediately). I have noticed that when using the computer in the simulator, as I am traveling up to the ceiling, the ASC time decreases (probably because I am decompressing on the way to the ceiling), but then I wait at the ceiling for the ascent time to become zero, indicating that I am supposed to wait for ASC time to become zero at the ceiling (therefore it does not take into consideration the time to get to and wait at the mandatory safety stop, or the time to get to the surface). What if there are multiple deco stops, how long will I know to wait - simply rely on the arrows?

This is all confusing.

 

[dumpsterDiver]

Wow, it tells you how long it takes to get from where you are until you can get to the surface. When the ascent time approaches zero, then that means you can go to the surface .

You should not exceed about 30 feet per second on the ascent.

 

[Bombay High]

If you try this without really knowing what you are doing, you have a great chance of either getting bent or drowning, so don't do it!!!!

You most likely wont have enough gas to fulfil your deco obligation, if you are a beginner who incurs a deco obligation. As Ian says - dont do it.
And if you find yourself between a rock and a hard place, it is better to risk DCI than to drown.

---------- Post Merged at 07:41 PM ---------- Previous Post was at 07:39 PM ----------

This is all confusing.

It will not be, as you gain experience and understanding. Until then, stay safe.