Dive Table

[randytay]

So I got the PADI dive table because I am taking the PADI DM course and comparing with my NAUI table, the NAUI's version is way more conservative.

Now I know they are all in some way based on the USN, so my question is, which table is closer to the USN or maybe the NOAA recommendations?

 

[tbone1004]

NAUI tables ARE the USN/NOAA tables. They are stopped down one stop basically, but the numbers are the same for the NDL's. PADI did their own thing, and for repetitive diving they are much less conservative. The USN tables were never designed for more than 1 or 2 dives a day because that was what they limited their divers to. Hence the 24 hour reset

 

[randytay]

NAUI tables ARE the USN/NOAA tables. They are stopped down one stop basically, but the numbers are the same for the NDL's. PADI did their own thing, and for repetitive diving they are much less conservative. The USN tables were never designed for more than 1 or 2 dives a day because that was what they limited their divers to. Hence the 24 hour reset

What do you mean by stopped down 1 stop? Was that more or less conservative?

 

[SeaCobra]

I am guessing you are not talking about the NAUI RGBM no-calc tables and are looking at the regular old basic tables. By 'stepped down' means every dive NDL is backed off one block. For example the USN has a NDL of 40 minutes at 80 fsw, while the NAUI tables are 35 minutes for 80 fsw.

Jeff

 

[tbone1004]

I was referring to the older NAUI tables, we still teach with those.
What he said, stopped down one to be more conservative in NDL's, the SIT is identical so no change in the letter groups etc, just the dive times.

 

[Charlie99]

So I got the PADI dive table because I am taking the PADI DM course and comparing with my NAUI table, the NAUI's version is way more conservative.

Now I know they are all in some way based on the USN,.......

The older NAUI table (the non-RGBM one) is based upon USN tables. The PADI one is not.

The repetitive dive calculations on the NAUI/USN table are based on the 2 hour compartment of the deco model. This is appropriate for Navy style diving, which can include dives on surface supplied air for many hours while working on the bottom of ships in the 20' to 50' range.

When used for normal recreational scuba profiles, using only the 2 hour compartment to calculate allowable repetitive dive times results in very short repetitive dive times.

The PADI table was designed from the beginning for recreational open circuit scuba divers and the repetitive dive calculations are based on the 60 minute compartment. This results in more realistic allowable dive times for repetitive dives.

For those very few dive sequences where the controlling compartment is slower than 60 minutes, the PADI table has the ad hoc WXYZ rules that require minimum 1 hour or minimum 3 hour surface intervals under some rare circumstances.

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The decompression model underlying the PADI RDP is significantly more conservative than the deco model upon which the USN and NAUI tables are based. Tables do not implement the full model and make simplifying assumptions to be able to generate a table with reasonably easy calculations for divers. The assumptions made in doing this conversion to tables were different for the USN/NAUI tables and the PADI tables.

 

[The Chairman]

There is more misinformation about tables out there than good. Sad that, but people often want to be the answer man without doing the research. Charlie 99's answer seems to be reasonable and accurate based on my own research.

Did they remove the "Wheel" from the PADI DM training? That's a fun one to play with.

 

[knotical]

Did they remove the "Wheel" from the PADI DM training? That's a fun one to play with.

Yep. After they came out with the eRDPML, the multilevel version of the calculator, they discontinued the wheel. It was fun.

 

[The Chairman]

You could tell those who had training with a slide rule when it came to using them.

 

[knotical]

You could tell those who had training with a slide rule when it came to using them.

By our gray hair?