AN/DP versus Extended Range Diver

[Ste Wart]

Deeper diving isn't as cut and dry as a few glib internet comments normally portray during deep air discussions.

:thumbs-up

Nicely put.

 

[Slamfire]

My Advanced Nitrox/Deco Procedures was taught with two deco gasses. Every dive was with two bottles, I'm guessing there's some variation in how the course can be taught.

TDI is known for allowing a wide berth for instructors to expand on the way a course is taught. So I'm sure that going to a 2 bottle an/dp course is perfectly fine. However, the minimum requirements set in the standards are:

From the TDI Course Standards Required Skill Performance and Graduation Requirements

AN/DP: Demonstrate comfort swimming on surface and at depth carrying a single decompression stage bottle. Demonstrate ability to drop and retrieve and single decompression cylinder while maintaining position in the water column.

Trimix (I don't have to ER standards): Demonstrate competence managing two stage cylinders including drop and recovery while maintaining position in the water column.

Advance Trimix: Demonstrate competence managing three stage cylinders including drop and recovery while maintaining position in the water column.​

It'll be awhile before I start considering progressing to furthere training, I just want to dive for now.

IMHO, this is always a good idea.

But I am curious about which course to take next, TDI seems to have a few different classes that I'm not sure about. I'm glad this question was asked.
When I do look to take more training, I'm considering going to Okinawa for training. The shop down there I'm looking at is NAUI Tech, so I'll have to look into what course to take next if I go there.

I jumped from AN/DP to Trimix, all within TDI. I also looked at other agencies, but they were more restrictive and/or fractured in their courses. In order to get to the equivalent of the Adv Trimix level you would have needed to take more courses. I like to do at least around 100 dives in between relevant courses. You do sharpen skills and learn a lot by simply doing time under water. If, like you say, you dedicate some time to just dive in between courses, you might end finding that agency tracks that split courses into smaller bits are wasteful and time consuming.

 

[Tortuga68]

I also did AN/DP with two deco mixes; 50 & 100%

Still went on to the ER, just more chance to practice & as I said the cert came in handy when I needed to to meet the requirements

Also worth noting that in some regions approriate certification is required to get deeper coverage from your DAN insurance

 

[Trace Malinowski]

......

 

[Trace Malinowski]

Sorry, Wart, I edited my post in an attempt to avoid a deep air debate, but I should have left it.

 

[Ste Wart]

Sorry, Wart, I edited my post in an attempt to avoid a deep air debate, but I should have left it.

It's debated endlessly on scuba forums.

On one of the other dive forums I visit, a poster pointed out that there is no Trimix available at the Bikini atoll . I wonder how many would opt to dive deep air then?

 

[DA Aquamaster]

TDI AN/DP with two deco gasses seems to be a common theme. At the time I took it the options were TDI with the use of O2 percentages up to 100%, or IANTD with a 50% O2 limitation.

The TDI AN/DP course made a lot more sense, especially with the instructor teaching 2 deco/stage bottles.

When Marci took the same course, I repeated it with her just to see how it was taught in a cave environment and TDI was still a hands down choice over IANTD as 100% O2 is almost the gold standard for N FL cave deco. And in that course the instructor again used 2 bottles - one with 100% and another with 32% as a stage/travel gas.

----

The difference between TDI's extended range course and their normoxic trimix course is (literally) 5 slides on the powerpoint presentation and two additional dives using trimix. The course then extends the certified depth to 210 ft. And again, the instructor I used taught the course with 2 deco gasses - a travel/first deco gas and a second deco gas.

If I have a potential objection to the TDI normoxic trimix course, it's that the minimum course standards are a little on the light side in temrs of total numbers of minutes required in the water over the course. However in the real world it really comes down to the instructor and they have the ability to beef the course requirements up substantially.

The advantage of the "two bottles in each course" approach is that by the time you get to hypoxic trimix, the bottle management skills are a non issue.

 

[Pullmyfinger]

I jumped from AN/DP to Trimix, all within TDI. I also looked at other agencies, but they were more restrictive and/or fractured in their courses. In order to get to the equivalent of the Adv Trimix level you would have needed to take more courses. I like to do at least around 100 dives in between relevant courses. You do sharpen skills and learn a lot by simply doing time under water. If, like you say, you dedicate some time to just dive in between courses, you might end finding that agency tracks that split courses into smaller bits are wasteful and time consuming.

Slamfire,

Thanks for your perspective on this. When the time comes for me to take more training travel will be involved, since there's nothing available locally. With this in mind I'd rather take a more complete course instead of smaller ones.

It's hard to overlap the courses from different agencies and see where you'd fit in, they all have different names for their courses with differing requirements or goals.
When the time comes I'll look closer at travel and instructor options, thanks again for your thoughts.

-Mitch

 

[RTee]

Oops. :blush:

I've been kind of handling two deco bottles for a while.

Due to my propensity for sub-clinical DCS symptoms, I've carried a bottle of 40% for a long time, and use it for an "ascent" gas as well as my pony when solo. (No, Virginia, I do not dive solo below the MOD!)


When I did AN/DP, I argued my instructor into letting me carry both 80% and 40%.

My AN/DP course was done with doubles on back and two stage bottles...one 80cft (40%) and one 40cft (100%) from day one at the request of my instructor.

 

[CaveMD]

My deco class was done with doubles, 1 bottom mix stage, 1 deco gas.