Which Air Tables Do You Like Best?

Feel Free to explain why you like a certain table better.

why would Ineed tables to fill my tires?

RGBM, VPM or a derivation there of. (Reduced Gradient Bubble Module, Variable Permeability Model)

Most of the other tables are based on the Haldane concept, which although it worked well for many years has been shown to be outdated.

It doesnt account as accurately for tissue loading or offgassing as a RGBM or VPM table does, especially when getting close or in some cases exceeding NDL's.

Dear Readers:

Gas Loading

Surprising as it may seem, virtually all models, including the RGBM, use the gas loading and unloading concepts of Haldane. That is, they utilize “compartments” that are loaded in parallel. These have halftimes that are unchanged by any external circumstances.

This concept has not been shown universally to be outdated. [It is, however, incorrect on the basis of my research. It does not work for the type of decompression performed at NASA.] Readers of the Ask Dr Deco forum will note that I constantly argue that excessive activity at depth will load more gas and make you vulnerable to DCS on the surface. This would not really be argued against by anyone, but immutable halftimes cannot take into account this fact.

Second, I counsel against sleeping during the surface interval because it reduces off gassing. This is also a result of the half time changes and is not in any algorithms, because they are essentially Haldanian. This is also backed by research in the past ten years.

Micronuclei

It is the concept of micronuclei (introduced into decompression the 1940s by Edmund Harvey) where newer algorithms depart from Haldane (metastable supersaturation). These microbubbles are not particularly important, however, unless one is involved in deep, decompression dives.

Microbubbles also play a role in excessive activity at the surface. Believe it or not, the decompression and off gassing is not over at the surface. Micronuclei generation under these conditions is not covered by the non-Haldane algorithms.

These new algorithms are wonderful tools, but please remember what they do and what they will not do.

Dr Deco :doctor:

Fizzyology is something I don't really know enough about. I have read reports of people who have got bent whilst diving inside the recommended table or computer limits. Some people are obviously more liable to sickness than others for what can be no apparant reason. I think tables are at best a guide for what's generally okay for most people. Complex tables for mixed gas and deeper longer decompression diving are beyond my needs as a non deco diving amatuer. I have a Mares dive computer and was trained to use Buhlmann though I find the Royal Naval tables more practical to use. I use the naval tables with a fudge factor to form the basis for a more conservative personal program that is linear and easier for me to remember. With my lazy ways I like to simplify things and generally dive in such a manner where observing complex tables and meticulous planning is not necessary. I suppose its rather tame but most of my dives last year rarely exceeded 30m and most were under 20m. I have trained to use nitrox but with the extra cost and difficulty of access, I don't find it practical and just use air. Basically I plan dive times within slightly lower limits of the naval no deco stop limits and add a standard 3min safety stop at 5m. I like the reassurance to know that in an emergency its reasonably safe to return to the surface at any time during a dive without a safety stop. This year I have done most of my diving from the shore in 9m or less, much of it between 2-6m staying well within the naval tables no limit zone. You get so much more time in water from your cylinder. Doing more actual diving in a day has upped the fitness level and I think improved my ability. At present I prefer doing longer dives in better vis where I don't need a torch instead of 20m to 30m dive for around 20/30 minutes.

NAUI is by far the most conservative...
PADI and IANTD are almost identical
US NAVY is probably the most liberal...

I have never seen the other tables....thus I have no opinion...I prefer to plan with the IANTD tables since I have those.

I see very few divers use their tables, regardless
of which model.And they rely on their computers or the dive brief.
In my debrief when i get to logging the dive profile
it is amazing howmany divers [all affliations] with many dives to their credit admit that they have forgotten how to use their tables.
IF you are worried about the strenghths and shortfalls of
tables, you are probably an obove average diver
GOOD ON YOU,MATE
Howard.

When I was first certified (25 years ago) there was only one table - the U.S. Navy Dive Tables. There weren't any dive computers either. What I call the recreational tables - PADI, NAUI and the other recreational cert agencies - essentailly all decreased the allowable bottom times in their version of the U.S. Navy tables. They correctly figured that U.S. Navy divers were young in age, and physically in shape; not so for the average recreational diver. These tables just added a little safety factor. Nothing wrong with that.
But as computers came along, they improved tremendously over the years. I'm on my 3rd dive computer right now. The UWATEC Nitrox Z I now use is absolutely fantastic! I have used this unit for repetitive staged decompression dives with open circuit compressed air, for open circuit nitrox, and for repetitive decompression diving on Semi-Closed Circuit Rebreathers (Drager Atlantis/Dolphin). I don't ever want to have to go back to using the tables, but I bring a set (U.S. Navy) along on every trip that I make.

SDI (the recreational cert agency of TDI) now offers an entry level course that does NOT even teach the tables. But each certified diver from this program is required to dive with a computer.
ut:

Scuba Chip once bubbled...
What I call the recreational tables - PADI, NAUI and the other recreational cert agencies - essentially all decreased the allowable bottom times in their version of the U.S. Navy tables.

Click to expand...

While the above is true of tables such as PDIC, SSI, YMCA, and NAUI; the PADI tables use a different decompression model and have very different limits for repetitive dives.

While Navy tables are more liberal for first dives, the PADI tables allow much more time on repetitive dives.

Charlie

I The only tables I have experience with are the SSI tables and a little round NAUI device. The NAUI gives about the same result but is much, much easier to use.