What is SSI's "Decompression Diver" course?

[KenGordon]

As discussed, that would work if it has the same gas as your back gas and allows you the option of switching wherever a catastrophic gas failure happens. If you are carrying a higher nitrox mix for decompression then the MOD of that may not match your back gas. This will prevent you from switching on certain profiles.

you’d have to read the course notes or speak to an instructor, but perhaps the plan is to always use the same gas for backgas and deco gas? 40% is not much of a deco gas unless you are doing a dive than needs several and there will be a richer one to be used shallow.

You seem to have it in for this course when really it is just an entry level deco qualification. It doesn’t fill the same niche as more advanced courses but I would say it is better than people doing deco dives with no training at all.

 

[BoltSnap]

ou seem to have it in for this course when really it is just an entry level deco qualification. It doesn’t fill the same niche as more advanced courses but I would say it is better than people doing deco dives with no training at all.

Yes, EXACTLY!!! People here seem to judge the course by the "affluent" western world standards. This course of extreme relevance to my part of the underprivileged world who the dominant majority of the divers here can't afford the training nor the equipment for technical diving yet they want/need to dive deeper and stay little longer. If nothing else, this course will/should bring out the complexities and ramifications of using mixed gases and deep/required stop deco. diving.

People in my world are diving deep and stay long without ANY relavent training at all, none. They are getting hurt and can't even afford to treat themselves properly. Perhaps this type of course will give them a chance to not get hurt and avoid serious injuries by getting some more training and gaining a little more knowledge, better than nothing at all.

 

[Angelo Farina]

I agree a lot with this. How much reduction in deco is generated from using a 40% mix versus a 32% in the bailout bottle? Say from a 10 minute deco penalty?

I have no software to answer the question, but I would assume/guess that the rich mix would shave less than 3 minutes of deco. That seems like a bad trade off in the risk/reward category. If that is what an agency is teaching, I would really like to hear the logic in how they defend that guidance.

Perhaps they just assume you are really not going to tox out at 130 on 40% for a while, and assume the diver will initiate an immediate ascent?

I do not think that SSI employs any accelerated deco procedure with highly-oxygenated deco tank in their basic recreational deco dive course.
My idea is that you use the same gas for the depth dive and for the deco. Which can be Nitrox up to 40%, of course within the maximum depth allowed by your mixture.
So you can exceed NDL and perform some reasonably short deco stops, keeping the same back gas.
An additional tank is welcome as a source of redundancy, but it is assumed that it contains the same nitrox mixture as the main tank, and the dive planning should not consider it in the gas planning, it is just a safety addon.
"Gas switching" is something technical in my understanding, it requires an advanced computer capable of taking into account the gas switch, which is something definitely "technical".
And what's the benefit? Two or three minutes shorter deco stop, which then you will certainly extend by at least 5 minutes for additional safety?
I am a recreational deco diver, but I never practiced gas switching, and my basic computer does not allow for this.

 

[Angelo Farina]

Yes, EXACTLY!!! People here seem to judge the course by the "affluent" western world standards. This course of extreme relevance to my part of the underprivileged world who the dominant majority of the divers here can't afford the training nor the equipment for technical diving yet they want/need to dive deeper and stay little longer. If nothing else, this course will/should bring out the complexities and ramifications of using mixed gases and deep/required stop deco. diving.

People in my world are diving deep and stay long without ANY relavent training at all, none. They are getting hurt and can't even afford to treat themselves properly. Perhaps this type of course will give them a chance to not get hurt and avoid serious injuries by getting some more training and gaining a little more knowledge, better than nothing at all.

So, if these are the goals, why your "not affluent" people do not rely on cheap club-based training within CMAS or BSAC certification procedures?
These cost much less than PADI or the like, the clubs usually also provide equipment at very small rental prices, and these courses already include deco procedures inside the normal certifications.
This is the standard here in Europe and UK, PADI is just for wealthy people who like to waste their money and go to expensive holidays in luxury resorts.
Nothing bad with this, I worked as an instructor in those luxury resorts!

 

[BoltSnap]

if these are the goals, why your "not affluent" people do not rely on cheap club-based training within CMAS

CMAS is present here and has the worst reputation. Their C-cards are literally sold to people who don't want to go through a course and to uncertified instructors who want to run courses and offer their student c-cards without being actual instructors. There are people here who have thousands of CMAS cards and printing machines and do what they please without ANY follow up or investigation by CMAS. CMAS knows about this disaster and did NOT do anything at all, not even a token investigation. I know about this first hand. CMAS SUCKS!!!

people do not rely on cheap club-based training within CMAS or BSAC certification procedures?

The club based training is dying in general and is only surviving in VERY limited locations in Europe. No instructor here is going to volunteer their time in a club to certify others for free. It just isn't worth it for anyone.

the clubs usually also provide equipment at very small rental prices,

Who is going to safe keep and maintain this equipment? The club based model is a failure in this time and age for all practical reasons.

 

[scubadada]

I do not think that SSI employs any accelerated deco procedure with highly-oxygenated deco tank in their basic recreational deco dive course.
My idea is that you use the same gas for the depth dive and for the deco. Which can be Nitrox up to 40%, of course within the maximum depth allowed by your mixture.
So you can exceed NDL and perform some reasonably short deco stops, keeping the same back gas.
An additional tank is welcome as a source of redundancy, but it is assumed that it contains the same nitrox mixture as the main tank, and the dive planning should not consider it in the gas planning, it is just a safety addon.
"Gas switching" is something technical in my understanding, it requires an advanced computer capable of taking into account the gas switch, which is something definitely "technical".
And what's the benefit? Two or three minutes shorter deco stop, which then you will certainly extend by at least 5 minutes for additional safety?
I am a recreational deco diver, but I never practiced gas switching, and my basic computer does not allow for this.

I'm with you, my second cylinder contains back gas and can be used at any depth I am diving, no gas switching, no accelerated deco.

However, SSI talks about a decompression cylinder and gas switching. @L13 did a calculation for accelerated deco on 40% with 32% back gas, nearly no gain.

 

[Angelo Farina]

CMAS is present here and has the worst reputation. Their C-cards are literally sold to people who don't want to go through a course and to uncertified instructors who want to run courses and offer their student c-cards without being actual instructors. There are people here who have thousands of CMAS cards and printing machines and do what they please without ANY follow up or investigation by CMAS. CMAS knows about this disaster and did NOT do anything at all, not even a token investigation. I know about this first hand. CMAS SUCKS!!!


The club based training is dying in general and is only surviving in VERY limited locations in Europe. No instructor here is going to volunteer their time in a club to certify others for free. It just isn't worth it for anyone.


Who is going to safe keep and maintain this equipment? The club based model is a failure in this time and age for all practical reasons.

Sad to hear this. Times are not the best for scuba diving, and I retired before seeing this failure. 30 years ago CMAS or BSAC were the top, almost equivalent to the best tech teaching, but much cheaper.
A lot of things went the wrong way, of course, and I see that the future of scuba diving is dark.
It probably will survive only as a sport practiced during holiday trips in luxury resorts, and only in some favourable destinations.

 

[johndiver999]

you’d have to read the course notes or speak to an instructor, but perhaps the plan is to always use the same gas for backgas and deco gas? 40% is not much of a deco gas unless you are doing a dive than needs several and there will be a richer one to be used shallow.

You seem to have it in for this course when really it is just an entry level deco qualification. It doesn’t fill the same niche as more advanced courses but I would say it is better than people doing deco dives with no training at all.

Does this make sense? Are you going to get 10 or 15 minutes of required deco, diving on a SINGLE tank in around 80 feet of water with 40% (83 feet depth is around 1.4 pp oxygen with 40%, I think).

Probably hard to do for a student to have that kind of gas consumption rate on an initial dive with sufficient reserves. Still not seeing the logic of 40% for doing 10 minutes of deco?

 

[scubadada]

...A lot of things went the wrong way, of course, and I see that the future of scuba diving is dark.
It probably will survive only as a sport practiced during holiday trips in luxury resorts, and only in some favourable destinations.

See Question - How old are you and how long certified? Poll- please take part!

 

[CAPTAIN SINBAD]

Yes, EXACTLY!!! People here seem to judge the course by the "affluent" western world standards. This course of extreme relevance to my part of the underprivileged world who the dominant majority of the divers here can't afford the training nor the equipment for technical diving yet they want/need to dive deeper and stay little longer. If nothing else, this course will/should bring out the complexities and ramifications of using mixed gases and deep/required stop deco. diving.

People in my world are diving deep and stay long without ANY relavent training at all, none. They are getting hurt and can't even afford to treat themselves properly. Perhaps this type of course will give them a chance to not get hurt and avoid serious injuries by getting some more training and gaining a little more knowledge, better than nothing at all.

I can personally relate to the economic constraints in which diving happens in many parts of the world. Expensive tech courses, specially by agencies who preach helium below 100' have no market. Back gas decompression works. I would prefer that they do that in a HOG back plate and wing, which they can get for 400 USD instead of doing the SSI decompression diver course in a recreational Scubapro Hydros BCD which is 1200 USD. No one is saving any money by sticking to a recreational configuration.

An H Valve will cost 83 USD. I am not sure if CMAS is doing these dives in long hose but I would strongly recommend that. So when you add the second first stage and swap the hoses, you are still under the cost on one Scubapro Hydros BCD! Now you are ready to do a full TDI Advance Nitrox and Decompression Procedures class, which enables you to do decompression on 100% oxygen. This is why this "in the middle" certification, which is neither rec nor tec, does not make any sense.

Nice to see you here Burhan! Long time no see mate. Hope life is well. Lets catch up outside the scubaboard sometime.