First Dive Computer

[mitsuguy]

If you don't mind me asking, what exactly do you mean by

Most models are based on RGBM, Buhlmann, DSAT, the US Navy, or one of a few others.

(Sorry if this should be known, but that's kind of why I posted the thread, to learn more about this stuff )

So, because it is all theoretical, there are different theories on which is correct and which is the best algorithm - in essence, which halftimes and M-values get you bent and which ones keep you safe...

In the beginning, there was the US Navy - essentially the only ones interested in diving with enough resources to come up with estimates for what works and what doesn't. There work was mostly made up the good old fashioned way - using humans for guinea pigs - if someone got bent, it got marked as bad, someone made it, not bad... Then there was NOAA and other organizations that used the Navy stuff as a basis, then they worked from there. Things like nitrogen off-gassing rates were some of the more important variables between the different tables - one of the reasons PADI tables are great and allow for more bottom time on repetitive dives versus the Navy tables, which were designed around decompression diving. Then came this guy named Wienke who did some work on the RGBM models, reduced gradient bubble model. He did lots of work with doppler ultrasound and listening for microbubbles. His tables worked to prevent this microbubble formation.

Because of this, models based on RGBM appear to be much more conservative than all previous models. There haven't been any significant differences in rates of DCS of one algorithm versus the other, at least to my knowledge...

 

[Hatul]

The Suunto does not show nitrogen loading except in the Dive Manager on the PC.

Adam

 

[CPH]

The Galileo's show nitrogen loading during the dive, an O2.

 

[mitsuguy]

The Suunto does not show nitrogen loading except in the Dive Manager on the PC.

Adam

There is no bar graph? I've never personally used a Suunto on a dive, just looked at co-workers and other divers - usually because they are showing me that they made it into deco when I haven't...

I was under the impression every dive computer had some sort of bar graph that shows nitrogen loading, like every single Oceanic...

 

[Supermanwoot]

Mares Puck. Its around $300

You wont get an integrated compass for that price but don't worry about it, you can get a great wrist compass for $50.

I don't own a puck, but just fooling around with one and looking at the different dive computers I felt like the puck was the best low-cost computer and the easiest to use.

It won't blow you away with cutting edge features, but it does what you want a dive computer to do and won't confuse you underwater.

 

[Hatul]

There is no bar graph? I've never personally used a Suunto on a dive, just looked at co-workers and other divers - usually because they are showing me that they made it into deco when I haven't...

I was under the impression every dive computer had some sort of bar graph that shows nitrogen loading, like every single Oceanic...

The bar graph in the Suunto you're seeing is just a graphical representation of the non deco time if the computer is in air mode. My Oceanic Prodigy shows the nitrogen loading of the highest loaded tissue.

Adam

 

[DiveNav]

The Suunto does not show nitrogen loading except in the Dive Manager on the PC.....

Same Suunto models have the Consumed Bottom Time bar graph (equivalent to 1 - No Deco Time .... normalized) that is a function of your nitrogen loading & depth

 

[rongoodman]

Bubbletrubble - as I am still learning about dive computers and what they have to offer, the Cressi Archimede II states "The new software analyzes the data of 12 sample tissues (previously 9) for even more accurate monitoring of tissue saturation and de-saturation mechanisms." Do you know how this process works? How do they obtain the sample tissues? Is this from the diver or is this maybe from a study they used in order to create the "estimated" nitrogen levels

Most dissolved gas models these days talk about "compartments" rather than tissues. There is some correlation, in that blood and nerve tissues are faster to on and off-gas, and bone is slower, but they're just mathematical models, not exact analogues of specific body tissue. The body is more complicated than that.

 

[Hatul]

Same Suunto models have the Consumed Bottom Time bar graph (equivalent to 1 - No Deco Time .... normalized) that is a function of your nitrogen loading & depth

The graph is just a representation of the non deco time, it's the same thing as the number just in a different form, and not nitrogen loading. When you leave the water a nitrogen loading graph will show the residual nitrogen load in the highest loaded tissue, but the Suunto graph shows nothing on the surface (yet you still have residual nitrogen).

This is one difference between Oceanic and Suunto display and I prefer the Oceanic in this regard.

Adam

 

[Jewls]

Thanks everyone for your input on the different qualities of the dive computers. I still have not made up my mind yet as to which one would be best for me. I've stopped at a couple dive shops to see if they carry the Cressi Archimede II and neither of the shops I went to carry Cressi products. One shop told me they didn't like the quality of Cressi products and woudn't recommend their dive watches. I've been told and have read a lot of really good reviews about Suunto (apperantly all they make are watches, computers, monitors), so I can appreciate that they would be made of good quality. I think my best bet now is to get my hands on one, play with it and maybe try one out in the pool.