Basic decompression procedures

[String]

Lots of places operate the TDI courses as combined Adv Nitrox and Deco Proc.

This makes a great deal of sense due to overlap in the topics and the dives.

Plus why certify for deco if you arent allowed to use accelerating gases or why be allowed to use 100% if you arent allowed to do accelerated deco... The courses really are linked too strongly to separate.

 

[amascuba]

Lots of places operate the TDI courses as combined Adv Nitrox and Deco Proc.

This makes a great deal of sense due to overlap in the topics and the dives.

Plus why certify for deco if you arent allowed to use accelerating gases or why be allowed to use 100% if you arent allowed to do accelerated deco... The courses really are linked too strongly to separate.

I totally agree with you, but the TDI Advanced Nitrox book focuses more on 'best mix' rather than accelerating decompression.

 

[captain]

I am not sure what you consider longer bottom time and I am asuming you want to use air as your only gas for simplicity. On a 130 foot dive using standard Navy air tables you could triple your bottom time to 30 minutes over a no decompression limit of 10 minutes with a 20 foot 3 minute stop and a 10 foot 18 minute stop for a total ascent time of 26 minutes. Not too bad a deco penality for 20 minutes more bottom time. The issues are proper gas planning, holding stops and repetitive dives. Accelerated deco would be benefical especically if doing repetitive dives. I think Mike Ferrara's advise is a good way to go to learn deco procedures you can apply to planning even if you don't use nitrox.

 

[String]

I totally agree with you, but the TDI Advanced Nitrox book focuses more on 'best mix' rather than accelerating decompression.

Thats because in theory Adv Nitrox doesnt qualify you to do accelerated decompression (actually it maybe no decompression at all), whereas the decompression course doesnt qualify you for different mixes.

Its why the courses are best combined

For the final exams i found myself referring to notes from the other book and using both as well. They're so linked i think its daft to split or take separately (although i guess for financial reason it maybe done).

Would also like to add i learnt more on those courses than any other diving course in my life. Got an incredibly good skill work out from instructor and emerged a far better diver.. (in my view obviously). Probably the most productive course in terms of money:gain ive ever sat.

 

[Rick Inman]

I am glad that when I did my IANTD Advanced Nitrox/Deco, I also included Adv Rec Trimix. I figure, as long as there are going to teach me to dive deco profiles over 100', it would be nice to be straight while doing it.

What a shock! I was right!!

 

[amascuba]

I figure, as long as there are going to teach me to dive deco profiles over 100', it would be nice to be straight while doing it.

You mean you're not straight when you dive deep air?

 

[do it easy]

You mean you're not straight when you dive deep air?

That's why all the macho deep divers won't dive deep air...

 

[grazie42]

This is from www.IANTD.com:
Advanced Nitrox Diver
This program is designed to extend the divers knowledge with O2 mixes of 22 to 40% and up to 50% for decompression. It further develops diving skills and provides a greater understanding of the Nitrox diving concept.

I´d say that´s the course you´re looking for.

For some reason I couldn´t find their complete standards there anymore...from the standards I do have (2003), "decompression specialist" certifies you to do decompression with nitrox from 50-100%, this would be the "main" thing you´ll miss out on if you "only" do "adv. eanx"...I´d think that any/most instructors would cut you a good deal if you combine them, it would be worthwhile to ask and decide based on cost/benefit for YOU...

If you are going to spend any time near 120ft (or deeper) I´d definetly recommend that you go for "recreational tmx" and "decompression specialist" combined as this will:
-qualify you to 130ft
-Allow you to use decompression mixes of 50-100% and learn the theory you need to use them.
-Nitrox of 28-40% (compared to 22-40% for adv. eanx, IMO, 22-26% isn´t much good to you at this level anyway)
-Let you dive helium that will allow you to do the dives from 100-130ft without being significantly impaired by nitrogen narcosis.

Combining them should also allow the instructor to cut you some kind of deal...

My advice would be to talk to an instructor about what you want to do, ask him to give you a few options on how to get the training you need (while staying within standards) and then choose what´s best for you...

ymmv...

 

[ianr33]

If you do Advanced Nitrox with TDI rather than IANTD you will be certified to use 100% O2. That was the reason I chose TDI.

 

[JKSteger]

Thanks for all your guidance and help. I've been put in contact with a couple of instructors. Thanks again,

J: