RGBM tables...

[PolsVoice]

I'm not sure if this would go in this forum or Physics of Diving.

I'm looking to get some plastic dive tables for the RGBM model, I'm looking not only for air tables but 32/36 Nitrox. I'm diving a Suunto Cobra and think it would be better to plan my dives using the algorithm my comp uses rather than traditional Haldane models.

Also, are there any computer programs (freeware) that are useful in calculating dives for unusual EANx mixes (40-50? 25-30?) Normally I just dive using the 36 tables with a modified MOD while on 40%, but there's gotta be something out there.

TIA

-Pols

 

[ScubaRon]

NAUI has RGBM based tables that you can probably buy from any NAUI dive center. Be aware that that does not mean they will give the same result as your Suunto: there are many different implementations of RGBM.

 

[Charlie99]

The Cobra uses a haldane-type dissolved gas model, not RGBM.

It tracks dissolved gas in multiple compartments like any other neo-haldane computer. RGBM comes into play only as "fudge factors" on the M-value limits of the dissolved gas model. Rapid ascents, sawtooth profiles, diving deeper than 100', short SIs, and ?? . ???... ??? will result in the M-values being reduced for up to 100hours after your dive.

As ScubaRon points out, using RGBM tables doesn't mean you will get the same result as your Suunto. Unless you are diving square profiles, the difference between any table and your computer when doing a multilevel profile will most likely be dominated by the multilevel aspect. You might look at using the PADI wheel.

One way to plan nitrox dives is to use equivalent air depths and air tables. You should be able to find info on this in the notes from your nitrox class.

 

[IndigoBlue]

NAUI has RGBM based tables that you can probably buy from any NAUI dive center. Be aware that that does not mean they will give the same result as your Suunto: there are many different implementations of RGBM.

Not all stores necessarily have them in stock yet. You may need to call NAUI in Tampa and order from them.

 

[BlueDevil]

Also, are there any computer programs (freeware) that are useful in calculating dives for unusual EANx mixes (40-50? 25-30?) Normally I just dive using the 36 tables with a modified MOD while on 40%, but there's gotta be something out there.

There are many software packages available to calculate just about any combination of gases you would ever use. Some are free, some are free but have "enticements" to pay a fee, some are straight out fee for use. Quite a few software packages are listed here: http://www.cisatlantic.com/trimix/tools.htm

One of the most popular at present is VPlanner: http://www.hhssoftware.com/v-planner/ (V-Planner is a shareware program. It has a 30 day evaluation period. After this period the program will remain fully functional, but will 'nag' with a reminder screen to register). This is a simple but very powerful program that will do just about anything and produces profiles somewhat similar to RGBM. If you decide to use it long term there is a modest fee which is well worth paying.

A simple, but somewhat outdated, program Is ZPlan (http://www.zplan.com/). It is free and not a bad option if you just want to "play" and get the feel for deco software. It was quite popular in the past but current thinking is that the deep stops generated by VPlanner are superior to those of ZPlan. It is Buhlmann based and has the option of deep stops (Pyle method), or no deep stops (straight Buhlmann).

BD