Deco Table comparison...

[all4scuba05]

If this is not the best place for this question, feel free to move it.

I'm looking at TDI's Navy Table(Deco Side) and Bulmann Deco Table.

First example:
Dive to 18.2M (60')
80 Min's BT
TDI Do a 7 min stop @ 3M(10')
Bulmann 18 min @ 3M(10')
Notice the difference in Deco Requirement

Second example:
TDI Dive to 190'(57.9M)
15 min's BT
Do 4 min's @6M(20')
Do 7 min's @3M(10')
Bulmann Dive to 57M(Just under 190')
15 min's BT
Do 1 min @12M
4 min @9M
5min @6M
11min @3M
In the second example TDI has you in water approx 17 minutes
Bulmann is approx 41 minutes.

Wow, what a difference. For those that would dive using Tables and not software... What table do you use? If not one of these two, then which one, and where does it fall as far as conservative or liberal? It would be nice to be able to dive TDI's times and not get a hit.

 

[Meng_Tze]

..
Wow, what a difference. For those that would dive using Tables and not software... What table do you use? If not one of these two, then which one, and where does it fall as far as conservative or liberal?

I assume you are comparing both tables with the same gas. Yes there will be a difference between USN and Buhlman tables. It is inherent to the basics and models.

I dive VPM predominantly now, but did many dives with Buhlman GF. Both work fine for me. Depending on the dive and conditions (environment and myself/buddy) conservatism is adjusted. We do use software to cut tables and have free reign in setting up a dive rather than fixed preprinted tables.

It would be nice to be able to dive TDI's times and not get a hit.

Start slowly with lots of padding and work from there. Depending on your training/experience, you can adjust which way you want.

 

[Mr Carcharodon]

Hmmm...the TDI deco time is about half of the Buhlmann. Is TDI assuming EAN-50 for deco?

 

[all4scuba05]

Start slowly with lots of padding and work from there. Depending on your training/experience, you can adjust which way you want.

Yes, that's what I am planning to be on the safe side.

I haven't seen a list yet of all the different charts in the order of conservative to liberal or vice versa. Is there one out there?

 

[all4scuba05]

Hmmm...the TDI deco time is about half of the Buhlmann. Is TDI assuming EAN-50 for deco?

Top of the chart says US Navy Air Tables. Perhaps they are the most liberal?

 

[all4scuba05]

I forgot to mention something important.
I am starting my Advanced Nitrox/Deco class on Tuesday. I don't plan on diving those tables 'til I'm certified.

 

[Meng_Tze]

Thank you for your honesty. You will learn a lot in that class and probably end up cutting your own tables....

 

[JS1scuba]

It appears you are comparing the USN tables (in TDI book) with Buhlmann Tables. The USN Tables are the absolute shortest tables around. They were designed for military application where a chamber is usually on-site. However, they are the most popular tables in the world and have an outstanding track record for working well.

Buhlmann tables are more conservative than USN and you will see more stops for a deco dive and shorter times for no-stop times.

Our company manufactures NAUTILUS DIVE PLANNER which has 5 different algorithms in it so you can compare different "tables" in a software planning mode. You can find that product at:

NAUTILUSDIVEPLANNER.COM you can also read a lot about models there as well.

IF you are taking an ADV EAN / DECO class this might be a product for you as well.

Regards,

 

[all4scuba05]

In that case, if I were to make a list of tables from most conservative to most liberal, which table would be in the middle?

 

[battles2a5]

The US Navy did not develop those tables for recreational divers. They were built for Navy divers that have support teams and an available recompression chamber. I would be willing to bet that the Navy's idea of an "acceptable" number of cases of DCS is different from ours. And they always have to option to throw a diver in the chamber is symptoms arise. The Buhlmann ZL-16 model is much more refined, more conservative and uses 16 compartments in the algorithm vs. 6 (i think) for the Navy. So they outcome is theoretically more "precise". FWIW, if I am using stock tables I will use Buhlmann. My computer uses the same algorithm so it makes things simpler. I use VPM-B for custom tables.