NAUI and TDI TEC course question

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divezonescuba

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I was looking at the TEC course equivalency charts for PADI and TDI. it looks like each agency does not credit each other and other agencies courses in exactly the same way.

Two deco tanks in addition to bottom gas are not used with PADI until TEC 50. I was wondering at what level courses do NAUI and TDI normally have divers receive training on the use of two deco tanks in addition to bottom gas.

This question arose as a non-PADI trained TEC diver mentioned that he only used 100% o2 to deco at 20 feet and used bottom gas for any other stops.
 
I believe TDI first requires demonstrating competence using 2 stages during the extended range class...

And on the TDI comparison page, it looks like the extended range class is the Tec50 PADI equiv
TDI Equivalent Ratings with Other Scuba Diving Agencies | SDI | TDI | ERDI

But technically there shouldn't be anything that would prohibit an instructor from teaching you how to use multiple deco gasses, even at the deco procedures level. There is no specific exclusion to using multiple gasses at that stage, nor a listed limit to how many deco bottles you are allowed to carry at the deco procedures level. The learning objectives for that TDI class include gas choices for deco, and includes gas switching procedures. Of course, I don't think that's the point of the deco procedures class, nor is it particularly likely that divers at that level would be racking up enough deep deco to require multiple mixes for staged deco.

As a clarification, although I am a PADI instructor, I only teach at the open water level, and I hold no PADI cert above the open water level. All my highest level tec certs are with TDI.
 
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I assume you mean two different gas Deco %, like Tot mention that starts at Ext Range and Trimix, but you actually get the knowledge in AN-DP of what gas to use.

I have used 50% and 80% bottles in some Tec dives but that was to reduce the Deco time, and I'm only AN-DP and Helitrox, but I meanly use single 50%, as I don't do much long dives.

As you progress in Depth and Time you will see the need of two Deco gases, so the courses are appropriate on how they were designed and it makes sense that they start at EXt Range and Trimix or Tec-50 using two Deco gases
 
When I took a TDI AN/DP (as well as IANTD ART) we only used one deco gas. I continued only using on gas until I took Trimix with TDI as I didn't see the need for two deco gasses for dives around 150fsw.

I did have a buddy who's TDI AN/DP class included two deco gasses so I guess a lot of this is up to the instructor.
 
Yes, I was referring to two deco gasses like 50% at 70 feet and 100% at 20 feet.

The TDI DP course standards had this required skill listed:

"4. Demonstrate ability to drop and retrieve single decompression cylinder while maintaining position in the water column."

on the other hand they also had reference to using more than one in the required equipment section:

"2. Decompression mix cylinder(s)"

So, that might be interpreted as you can have more than one, but you only have to demonstrate skill with one.

In TDI is appears that with the DP course you are certified to 150, while to get to 150 with NAUI you have to take Helitrox. Since the PADI TEC 50 course is to 165 there could be more need for the use of two different deco gasses.
 
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Each Agency have their criteria, but the instructor as well have the influence on guiding you according your goals and the environment you will dive in a safer way.
 
I no longer actively instruct through TDI, but I would not use two deco cylinders when teaching AN/DP. Because TDI allows instructors to go as far beyond standards in a course as they wish, I suppose it would be allowed, but as in all cases, an instructor going that far beyond the standards is taking a liability risk.

There is a big difference between handling one cylinder and two, and that is why the PADI Tec 50 course focuses on those skills primarily. Not only are the skills different, there is the potential for oxygen toxicity. If you only have one deco gas, there is no possibility of switching to the wrong one. The possibility that a student would switch to the wrong one is small, but if the student has not been properly trained for it, it can happen. If it does, when the lawsuit starts, the instructor will have to prove that the student was properly trained in a procedure that is not a part of the course but is instead part of a more advanced course.
 
With TDI, multiple stages and or Deco bottles start at the Extended Range course.
 
The current NAUI course lineup would have you using 1 deco gas for their heliox class and 2 deco gases for their trimix class. The names have changed over the years.

I don't know any agency advocating for students to use 2 deco gases for their initial deco courses which typically go to about ~40m/150ft. Usually 2 deco gases are introduced in a 2nd class and for depths deeper than ~50m/170ft.
 
This question arose as a non-PADI trained TEC diver mentioned that he only used 100% o2 to deco at 20 feet and used bottom gas for any other stops.

If I did a 120ft dive for 40mins I would probably use (only) O2 for that despite being trained to use multiple deco gases. Not sure how this example relates to your question about padi and naui?
 
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