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Aussie
10-15-2007, 04:46
I would like to know the actual Algorithm differences between different dive computers. I have been told that the Suunto computers that I am currently using are more conservative than other dive computers like the Palegic computers which I rarely see.

I would like to know what are the actual differences are in the field.

Are these differences only visable after series of constant diving profiles (ie multiple dives per day over several days)?

Aussie

bperrybap
10-15-2007, 06:01
Here is write up from a few years ago.
While I don't agree with the authors recommendations
about which units to use or avoid, it is an interesting
source of information:

Dive Computer Comparisons (http://www.underwaterbob.com/dive_computers.htm)

My philosophy is that if you want to dive more conservatively,
come up sooner rather than use a device that shortens
your time for you.

--- bill

Aussie
10-15-2007, 07:46
Here is write up from a few years ago.
While I don't agree with the authors recommendations
about which units to use or avoid, it is an interesting
source of information:

Dive Computer Comparisons (http://www.underwaterbob.com/dive_computers.htm)

My philosophy is that if you want to dive more conservatively,
come up sooner rather than use a device that shortens
your time for you.

--- bill

Thanks Bill,
Interesting read.

But it leaves more questions to be asked.

Firstly the test was based to two square profiles to 30msw for 16min with 1:49min SI. If divers were doing basic square profiles there wouldnt be a need for dive computers as we would all just stick to the tables. It doesnt show the full potential of each of the Algorithm.

What about the conservatism of the same computers on the following:

Multi level profiles
Multi level profiles over several dives
Reverse profiles
Desatuation times
Ascent voilations
Different Nitrox mixes
Gas switches
Personal adjustment
Altitude adjustmentWouldnt this give us a more accurate idea of what the Algorithm is like on more in the field like situations. Maybe an aggressive computer might have a conservative Desatuation time or vice verser. Conservative computer might be aggressive in its Altitude adjustment when compared to other computers altitude adjustment.

Questions remain to be answered.

Aussie

tbuckalew
10-15-2007, 11:27
Unfortunately, a very difficult question to answer for many reasons:

1) The actual algorithms used are pretty specific to many firms and not always shared. One of the exceptions to this is the RGBM model now used by some computers and posted in literature you can purchase (used doppler to actually visualize bubble formation in the heart to create the tables).
2) Many computers today allow the user to set the level of conservatism you would like to use (say you are an out-of-shape diver that does not exercise regularly - you may want to set it to be more conservative).
3) As every diver is different, there is no guarantee that nothing will ever happen to you while diving tables or a computer (there is an extremely good chance it won't).

In my opinion, find a computer with the features you are looking for and in the price range you want (you can go from a couple hundred to a few thousand easily) and work from there. The computers available today will do a good job for you, pretty much whatever you choose.

Aussie
10-15-2007, 18:25
Unfortunately, a very difficult question to answer for many reasons:

1) The actual algorithms used are pretty specific to many firms and not always shared. One of the exceptions to this is the RGBM model now used by some computers and posted in literature you can purchase (used doppler to actually visualize bubble formation in the heart to create the tables).
2) Many computers today allow the user to set the level of conservatism you would like to use (say you are an out-of-shape diver that does not exercise regularly - you may want to set it to be more conservative).
3) As every diver is different, there is no guarantee that nothing will ever happen to you while diving tables or a computer (there is an extremely good chance it won't).

In my opinion, find a computer with the features you are looking for and in the price range you want (you can go from a couple hundred to a few thousand easily) and work from there. The computers available today will do a good job for you, pretty much whatever you choose.

Yes tbuckalew,
Its a difficult question to answer.

I have noticed a few comments like "I prefer brand X as its less conservative to brand Y". So how does each Algorithm compare in the field? I believe the basic square profile left me wanting to know more.

Could it be said that divers choose an aggressive dive computer as it "allows" them more bottom time?

Could it be also said that most divers that should increase the level of conservatism on their computers actually don't?

I understand that every diver is different and that every dive is also different. But it comes down to what exactly are we getting with each different brand of dive computer and the Algorithm which it uses? Which computer is suited to a professional that does multiple dives each day and to a diver that does one in a blue moon?

Its not a question about features or price of the computer, its a question about primary purpose of having a dive computer and understanding how they work and comparing large range of them used in diving today.

Aussie

dannybot
10-20-2007, 14:58
My observations using a Suunto Gekko diving with my wife using an Aeris XR1 are that the Suunto is more conservative, especially on the repeat dives, but if you maintain a reasonable profile, and a SI greater than an hour, it is easy to avoid deco. If you ascend slowly, you can eliminate the disparity.

Hope this helps.

Danny