What is SSI's "Decompression Diver" course?

[Angelo Farina]

Maybe it's just me but I wouldn't call anything involving Deco a recreational dive but then again I guess it begs the question: what is the difference between a technical and recreational dive?

This question arose a lot of times here on SB and there is no unique answer, as different agencies and organisations set the limits at different positions.
Generally speaking here in Europe no profit organisations (such as Cmas, Bsac, Fipsas, etc.) tend to set the limit much higher than US based commercial for-profit agencies (Padi, Naui, etc.).
This is due to the fact that these organisations operate in a club-based environment, not for profit, and hence a typical diving course here can last 2-3 months and involve something as 20 hours in the pool and at least 3-4 weekends in the sea.
Even at first course the basics of deco procedures are taught, and already at the second level of training some small deco diving is employed. The idea is that a dive planned and executed beyond NDL is actually safer than a dive "just within" the NDL.
Planning and executing a deco dives requires a better equipment (here we typically use two complete regs with two independent valves even on a single tank, and compact twin tanks are also used for recreational diving) and more skilled divers, so in the end is safer.
A dive planned to be within NDL can easily switch to a full deco dive everytime the plan is exceeded, but at that point the diver is not prepared, equipped and trained for performing correctly the required deco stops. So planning for the worst is safer...

 

[berndo]

Even at first course the basics of deco procedures are taught, and already at the second level of training some small deco diving is employed.

Don't the French still dive to 60 m on air?
The German CMAS club used to use air tables to 63m/207 ft.:

Dekompressionsberechnung – Taucherpedia

Der Zweck einer Dekompressionsberechnung ist die Überwachung der Stickstoffsättigung im Körper des Tauchers und die Bestimmung von evtl. notwendigen Dekostopps beim Auftauchen. Sie ist zudem Teil der Tauchgangsplanung.

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[Angelo Farina]

Yes, Frenchs go even deeper than us with air. Here in Italy the limit is typically 50m, in France they exceed 60.
However, these are definitely technical dives. Currently CMAS limit for recreational diving is 40m, with back.gas "light deco".

 

[berndo]

Yes, Frenchs go even deeper than us with air. Here in Italy the limit is typically 50m, in France they exceed 60.
However, these are definitely technical dives. Currently CMAS limit for recreational diving is 40m, with back.gas "light deco".

I think the Germans restricted it to 40 on air in the 90s or early 2000s. BSAC still has a 50 m limit for air for advanced divers.

 

[Stoo]

Sorry but I am a bit confused and may not be understanding this correctly. If someone, who has taken this specialty or teaching this, could give a little more information and address my curiosity, Id be grateful.

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Going into decompression requires proficiency in backplate and wing with long hose and that is what our TDI's Intro to Tech does, or GUE Fundies or UTD Essentials. I believe SSI has its own variant called XR Foundations. Apparently, these are not required for SSI Decompression Diver. Am I correct to understand that this takes you outside of recreational diving into technical diving parameters WITHOUT the training and the gear configuration of tech? A tech course in a BCD jacket with split fins and snorkel??? A lot of questions come to mind

Is the single tank required to have an H-valve? How would you shut down the compromised valve if that is the only one you have?

How do you manage air share without long hose? Recreational hose lengths are good if you are taking the fellow straight up to the surface but if you have a deco ceiling above you, then it needs to look something like ...

View attachment 773910

instead of ....

View attachment 773911


So can anyone please shed some light on what exactly is SSI's "Decompression Diver" specialty???

I'm not familiar with the specifics of either of the courses you mention, but I can assure that safe decompression diving was going on for decades before someone cooked up the BP/W config. and long hose.

Recalling my first decompression dive in about 1976, I was wearing an Aqualung "life vest" with 8 pounds of lift, and a dual outlet set of 72s with no isolator. I still don't wear a long hose in open water because I prefer my air-sharing partner to be in my face with me hanging on to them and I have yet to hear a good reason to add 4' of rubber hose to my kit.

Personally, I think that SSI course makes a lot of sense. Most recreational divers shudder at the thought of completing a decompression stop. And they shouldn't. If a diver can hold a stop and manage their gas, then having the knowledge to properly complete an actual decompression stop is an invaluable tool. So many divers are brainwashed that if you don't own this gear, and have these 14 cards, you can't to this dive or that dive because you will 100% die.

And that's BS. Gear doesn't make someone a better diver. Knowledge and skill does.

 

[JMarc]

Don't the French still dive to 60 m on air?

Outside an organization, you do whatever you want.

Inside organization (profit or non profit), you are limited by law (the Code du Sport) at 60m on air, and that's reserved to holders of a PE60 or PA60 qualification with CMAS*** is considered as equivalent of PA60. There is no room in the law for other equivalences (for lower depth limits, the dive organizer has some agency to map outside certifications and even just experience to qualifications recognized by the CdS).

Is it wize is another matter, some are reaching the limits for sure.

 

[CAPTAIN SINBAD]

I'm not familiar with the specifics of either of the courses you mention, but I can assure that safe decompression diving was going on for decades before someone cooked up the BP/W config. and long hose.

Recalling my first decompression dive in about 1976, I was wearing an Aqualung "life vest" with 8 pounds of lift, and a dual outlet set of 72s with no isolator. I still don't wear a long hose in open water because I prefer my air-sharing partner to be in my face with me hanging on to them and I have yet to hear a good reason to add 4' of rubber hose to my kit.

Personally, I think that SSI course makes a lot of sense. Most recreational divers shudder at the thought of completing a decompression stop. And they shouldn't. If a diver can hold a stop and manage their gas, then having the knowledge to properly complete an actual decompression stop is an invaluable tool. So many divers are brainwashed that if you don't own this gear, and have these 14 cards, you can't to this dive or that dive because you will 100% die.

And that's BS. Gear doesn't make someone a better diver. Knowledge and skill does.

As I mentioned earlier, going into deco is ok if you are trained and equipped to manage issues without surfacing. K valves, H valves allow for redundancy without the need of a second tank. Similarly stage bottle with the same mix as your back gas also allows you to make that switch. Whether these options are covered in SSI decompression specialty or not, we are unsure. So far the discussion implies that stage bottle in this course is actually a deco bottle with higher O2 mix that will prevent you from switching at your bottom depth. In that case it will not count as redundant.

 

[gbirch]

For this course, the dives are planned as if the stage/deco bottle does not exist, i.e., the dive and deco obligations can be completed on the back gas. The stage/deco bottle is for an extra margin of safety by just switching the breathing gas or to accelerate deco by switching gas and computer. It is not intended to be a redundant back gas, for that the diver follows established recreational protocols and uses the buddy's alternate until at least one of the divers can switch to the deco/stage bottle. There is no prohibition against H valves if you would prefer that configuration. There is also no requirement to use a higher O2 in the deco/stage cylinder - these options are discussed in the classroom and practiced in the training.

 

[EFX]

Most recreational divers shudder at the thought of completing a decompression stop. And they shouldn't. If a diver can hold a stop and manage their gas, then having the knowledge to properly complete an actual decompression stop is an invaluable tool. So many divers are brainwashed that if you don't own this gear, and have these 14 cards, you can't to this dive or that dive because you will 100% die.

And that's BS. Gear doesn't make someone a better diver. Knowledge and skill does.

Except for "managing their gas" recreational divers have been doing decompression stops for years. They just don't realize it. They're called safety stops. Physiologically, there's no difference between a mandatory deco stop and a voluntary safety stop. They both off gas the critical tissue(s) to a safer level before ascending. The difference could be in the gas used to decompress and/or the precision of maintaining the stop (technical vs. recreational). While the original idea of the safety stop was to provide additional safety, it can also be viewed as a nudge toward the skill needed to hold deco stops for more demanding technical diving.

 

[gbirch]

Except for "managing their gas" recreational divers have been doing decompression stops for years. They just don't realize it. They're called safety stops. Physiologically, there's no difference between a mandatory deco stop and a voluntary safety stop. They both off gas the critical tissue(s) to a safer level before ascending. The difference could be in the gas used to decompress and/or the precision of maintaining the stop (technical vs. recreational). While the original idea of the safety stop was to provide additional safety, it can also be viewed as a nudge toward the skill needed to hold deco stops for more demanding technical diving.

Not sure I would agree with this. Physiologically, yes, they are the same process (regardless of gas being used - which just accelerates the physiological process), but in terms of the parameters of the process - vastly different. By definition, a recreational diver completing an optional (but recommended) safety stop has on-gassed Nitrogen below the "threshold" that would make a direct ascent to the surface a reasonably low risk, while a diver that has entered deco has crossed that "threshold" and now has a more elevated risk of decompression sickness should the diver ascend without a stop, and that risk goes up the further over that "threshold" they crossed. I put "threshold" in quotes because we all know that it is not some thin line of precise demarcation, but rather a zone between mostly safe and definitely bent.