Why you can't use the PADI RDP table for Multi-Level dives

[tursiops]

Well it is not because you say that it wrong that it is wrong
The procedures used were validated by COMEX and even they became a law. Yes an offcial law.

Can you please provide a citation to the COMEX procedures?

 

[jale]

Can you please provide a citation to the COMEX procedures?

I have already posted all the links but it looks that because it is not an US based system, or an US Navy table based system, it has no value for most of the posters

 

[tridacna]

This thread is an interesting read. The posts regarding using tables for a multi-level dive by tursiops, boulderjohn, steinbil, lowwall, jale, Bigbella, et. al. could easily be a good thread on it's own

True. But does all this talk of deco belong in "Basic" SCUBA?

 

[scubadada]

True. But does all this talk of deco belong in "Basic" SCUBA?

I think it is mostly about avoiding deco

 

[tridacna]

I think it is mostly about avoiding deco

Perhaps a bit advanced for "Basic". Maybe better in Advanced.

 

[Joneill]

This thread is an interesting read. The posts regarding using tables for a multi-level dive by tursiops, boulderjohn, steinbil, lowwall, jale, Bigbella, et. al. could easily be a good thread on it's own

And, as has been said, a great stimulus to buy and use a dive computer instead of dealing with tables

I’ll add that divers should understand the concepts of NDL diving (this is the basic forum so should really not be going into deco) and how their computer works - but, unless truly diving square profiles, tables seem overly complicated for multilple, multi-level dives per day.

 

[tursiops]

I think it is mostly about avoiding deco

Yes.

Perhaps a bit advanced for "Basic". Maybe better in Advanced.

Only some of the excursions in the thread.

tables seem overly complicated for multilple, multi-level dives per day.

It is not that they are complicated, it is that they are not applicable. You can easily go through incorrect procedures (as several have posted) but that does not give a valid answer for multi-level dives.
--------------------------------------------
The point of the original post -- in Basic on purpose -- was to inform why tables are mostly no longer taught in OW classes: OW divers do multi-level dives, and tables cannot be used to plan those dives without risking DCS (i.e., going into deco). The only non-computer planning exceptions I'm aware of are the eRDPml, the Wheel, and a extremely awkward procedure to emulate the eRDPml using a table; see attached publication by Duis for that procedure.

The thread evolved to tables vs computers, which was not the intent, and has occasional sidetracks by those who wish to compare incorrect multi-level procedures (GUE, MT92) versus the "right" answer.

Bottom line: there is no justification for using a dive-averaged depth instead of dealing with multiple levels in the dive, as a computer does and even the eRDPml can only approximate. The GUE procedure of smoothing out the bottom to a "average bottom depth" is OK, but not averaging a profile that goes from the bottom to the surface into some kind of "average" depth for the dive. The MT92 procedure provides a complicated Table 8 to help you work out the average depth of your multi-level dive, but then incorrectly says you can use that average depth with square-profile tables. Saying that the procedure is required by French law is hardly a reason that it is suddenly correct.

 

[steinbil]

The scientific method at its finest.

Wow. I'm quite unimpressed at the level of hostility and the unwillingness to try to understand the opposing view.

I'm not pretending to know how these methods were developed, but I have no reason to distrust the GUE training I've gotten. Using my clumsy explanations of the method as "proof" the method doesn't work, pretending like I devised the method, is a nice diversion. I'm sure you understand this, but couldn't resist the cheap shots.

I've had respect for you from some of the posts I've read on SB, which is why I directed my sincere questions to you in this thread, hoping to learn. It seems this respect was misplaced. I'm sorry I asked.

 

[steinbil]

It is not that they are complicated, it is that they are not applicable. You can easily go through incorrect procedures (as several have posted) but that does not give a valid answer for multi-level dives.

And all I've asked for is an example showing me that I'm wrong, and it doesn't work. If it's that hard finding an example of how it fails, I have a hard time believing that I can be so wrong.

 

[dmaziuk]

Wow. I'm quite unimpressed at the level of hostility and the unwillingness to try to understand the opposing view.

"We get it, we just don't want it": memorizing certain ratios that are "good enough" for certain gas mixes at certain depths may be great for one's brain development, but for actual diving: skip ten lunches and buy a computer.