I want to murder my computer and feed it to the fishies!

[Cave Diver]

But what I am not understanding is that my buddy right next to me - who is going up the same speed of me - is not getting any extra deco on his computer? When he starts going up it stops adding deco, heck it even takes some off. So is my comp just being it's uber-conservative self or am I doing something wrong?

This is exactly the point they are trying to get across to you. If you don't understand the differences in what the computers are telling you, and why, then you probably need to learn more about deco theory. The best way to do that is with an instructor or a mentor who is well versed in it. Learning from some random guy on the internet is not the way to do it, because you don't have any way to assess if they know any more about it than you do.

While the same may hold true in person as well, at least you are able to make a more personal assessment of them.

 

[melanie.]

Cave Diver - they (the computers) are spitting out different numbers because they are operating with different algorithms. These algorithms are based on different theories of how nitrogen is accumulated, stored, and released from our bodies. This is the bare-bone basics is it not?

What I am asking for is some tips on dealing with my specific computer. Not deco theory. If I wanted that I would not have posted within the MARES forum

 

[DuboisP]

Cave Diver - they (the computers) are spitting out different numbers because they are operating with different algorithms. These algorithms are based on different theories of how nitrogen is accumulated, stored, and released from our bodies. This is the bare-bone basics is it not?

not so bad
and also what the manufacturer chooses to secure the deco

What I am asking for is some tips on dealing with my specific computer. Not deco theory. If I wanted that I would not have posted within the MARES forum

in fact, i swapped to a Suunto after my Mares was very long to count down minutes

what is the computer of your buddy ?

 

[melanie.]

in fact, i swapped to a Suunto after my Mares was very long to count down minutes

what is the computer of your buddy ?

I am pretty sure it is a Suunto.. but don't quote me on it. So did you ever figure out why your Mares was so long to count down? Or did you just get another computer?
I know this computer will not take me as far as I want to go with diving, but for now it is all I have. Already I warn all my other buddies that I will hit NDL limits before them, and plan accordingly. But now it seems like I will have to take into account that it will not count down the deco minutes reliably when I am doing deco dives

 

[DuboisP]

So did you ever figure out why your Mares was so long to count down?

1rst dive at 128ft max, 7min deco max, 1 hour total
surface interval 2h30
2nd dive at 110ft max, 24min deco max, stop between 10ft and 16ft (was a beginner), so the deco was 34min.
re-read the manual, and decided to swap to a Suunto where the stop depth is more adaptative.
With the Mares, you must do at 10-11ft, which is unconfortable when the sea is bad
with the Suunto, you can be more confortable at 14 ft without adding a lot of minutes.

i'm now using the Mares in pool (50ft) or in gauge mode when i'm diving trimix, because it shows the seconds running.

 

[Jim Lapenta]

The computer should not be relied on to count down deco. You plan the dive. Not the computer. The computer is a tool. Nothing more. This is why every entry level tech course I'm familiar with utilizing deco has the diver using tables, a way of determining depth, time, and ascent rate.

If a computer is used it is in gauge mode. The fact that you and your buddy are using different computers with different algorithms and no plan other than do what the computer tells you is foolish and ill-advised. Pushing the computer into deco when it is clearly not made for that is seriously courting disaster.

The instructor that is sanctioning this, if indeed they are, is someone I'd not want to train with or have my kids trained by. Warning your buddies that you will hit NDL before them is not planning a dive. That's telling them I don't really know what I'm doing and I don't like what my computer is telling me so I'm going to say screw it and do what I want. I don't have a back up plan, I don't have a back up device, I don't have a contigency plan, and even though I do make a rough plan I get distracted easily and will say screw it over a lawn chair.

I would not dive with someone nor would I allow any one I cared about dive with someone that undisciplined on a recreational dive let alone a technical one. And deco is technical because you have put an overhead into the equation. And it sounds like you feel it's not that big of a deal. Any OW student that displayed your attitude would fail my class and not be issued a cert. No one else here is confused in any way. They see that this is not about some computer. It's about untrained people pushing their luck and engaging in unsafe diving practices. There is a right way to about doing decompression dives and this sure ain't it.

The computer is not being used, it is being misused and that's why it's not making sense. If it were being used in the right way it would be to keep track of time, depth, and maybe ascent rate. As should your buddy's to see that you are sticking to the schedule you develop with bottom times, depths, and stops. Written down, with contingency plans, and the discipline to stick to them. The sad fact is that if something happens someone else is going to be put at risk to assist a team like this and may get get hurt themselves. And that's just wrong on so many levels.

These are occasions where a rescue of divers that get into trouble because of things like this should maybe not even be done. Let Darwin win and not worry about it. All because IT SEEMS that people do not want to take the time and/or spend the money to properly train for, equip themselves, and conduct these dives.

 

[Jax]

Not optional, dumb!

So I've just done an hours deco,the last 30 minutes on 100% O2 and the computer wants an "optional" safety stop??!!

My Predator does not have a safety stop countdown and I'm guessing the X1 doesn't either. My point was that any computer with a safety stop countdown is really a recreational computer no matter what the sales literature may say.

Safety stop - NOT dumb.

Happen to be re-reading deco for divers, and in the 2nd Ch, (p 50-1), Mark P states that research using Doppler bubble detection shows that the person with the safety stop(s) shows a significant reduction in silent bubbles. "So much so, that immediately after the ascent there are less bubbles present [in the safety stop group] than in the group that that surfaced without stops measured after two hours, and after 45 minutes the number of bubbles for the [safety stop group] had reduced to zero."

 

[ianr33]

No no no, I never said Safety Stops per se were dumb! They are obviously very helpful at reducing nitrogen loads on NDL dives,

What I think is dumb is a computer that asks for a 3 minute safety stop no matter what. You really don't need a safety stop on a 25 foot dive.Neither do you need another 3 minutes at 15 feet once you have cleared a deco obligation. (Although it obviously can't hurt)

I had a Diverite Duo for a while,used it on a few Cave Dives before it died on me. Was just really amusing to me that I would clear deco on O2 at 20 feet then the silly thing would suggest stopping again for 3 minutes at 15 feet!

Safety stop countdowns to me indicate a computer is not really intended for technical diving. If you want to do more deco alter the VPM conservatism settings or the Buhlmann gradient factors to an appropriate value rather than following some arbitrary 3 minute stop.

/Rant Off!

 

[iztok]

Safety stop - NOT dumb.

Happen to be re-reading deco for divers, and in the 2nd Ch, (p 50-1), Mark P states that research using Doppler bubble detection shows that the person with the safety stop(s) shows a significant reduction in silent bubbles. "So much so, that immediately after the ascent there are less bubbles present [in the safety stop group] than in the group that that surfaced without stops measured after two hours, and after 45 minutes the number of bubbles for the [safety stop group] had reduced to zero."

He is referring safety stop after deco for a period of time on say 100% O2 at 10ft.

 

[Jax]

I wonder if Doppler studies were done on tech dives . . . when would the silent bubbles disappear for y'all . . .

Oh wait, we were talking about computers, and blindly following what one thinks it's saying . . .

:focus: