Redundancy Required for Decompression Diving?

[Bennno]

@dumpsterDiver
Not anymore.
The 'older' 3* divers did deep air and deco on single tanks... lots of people used to do it. I don't know when they changed that, though. The VDST tables go to 61m or 63m (210'?) and they used it before they had trimix training, afaik.
This must have changed it 15 or 20 years ago, maybe more.

 

[KenGordon]

There are three main reasons we have people with non BSAC qualification:

1 - they did an OW course abroad and totally loved it, came back to the UK and wanted more diving.
2 - they did an OW course abroad and were scared that they actually had no idea and wanted reassurance and further training, including sometimes them insisting they start again.
3 - they need particular timing or a want a particular instructor so take a course with whoever suits.

I think that the old fashioned approach is actually the one taken by the big commercial agencies. By categorising deco diving as completely 'other' and having stuff like having to not dive for a period of time if a diver goes past NDL they have created a whole new category of pushing things. Having hard rules rather than having divers evaluate risk.

That is understandable though, given that their business is 'pile them high and sell them cheap'.

Regarding your 'enabling' clubs to sit in a bunker - taking Nitrox as an example. Nitrox has been on the OW equivalent course since 2007 (at least). No extra courses required.

Diving qualifications do not stop anyone from doing anything. Diving courses should educate people so they can make informed choices. To get a 50m air qualification with BSAC you need to have done Ocean Dive, Sport Diver and Dive Leader. Each of those REQUIRES a number of experience dives and then Sport Diver and Dive REQUIRE post qualification depth extension dives. This means that anyone qualified to 50m MUST have had at least 6 dives (with a Nationally Qualified Instructor - not an assistant or club instructor) just to extend depth. This is on top of those involved with the lessons and the other experience dives (i.e. nonlesson dives to expand on diver experience of different conditions - so 20 dives in a quarry is no use). By the time they have done all this an enthusiastic Dive Leader will most likely have been diving for two or three years and have a 100 dives. By that stage they ought to be able to understand the need for redundancy, helium and so forth and so be making INFORMED choices.

If I were look back at earlier qualification schemes and manuals within BSAC I think (my manuals are 3000 miles away) that in the 70s and 80s a Third Class Diver, the then entry level and equivalent to Sports Diver, had a recommended limit of 50m, although it might have been 60m using the RN tables. It took about 20 dives to get to be 3rd class, but of course you knew your place in the pecking order.

So clearly, nothing has changed since the 50s.

Like combating underage sex or drugs with 'Just Say No' is bound to fail, telling people they have hard limits will fail. It isn't better to give people the tools and experience to decide for themselves.

If you want to see how that works out go Scapa Flow and count the single cylinder divers. There will certainly be none without a pony and probably none at all. If fact on some trips now there will be no OC divers at all.

If we want to consider modern practice, should we not think about whether people should be doing big OC dives?

TDI Advanced Trimix OC? They must be stuck in the 90s!

 

[Edward3c]

If all these divers sought qualifications outside BSAC/CMAS etc etc..

1. What does that say about BSAC / CMAS-derived clubs?

2. Why don't BSAC /CMAS-derived clubs internalise the knowledge that their members are acquiring?

3. What does that illustrate about the relationship between the training provided and the level of dives members are empowered to undertake?



The way I tell it, they are enabled to sit around in a bunker wearing blindfolds.

Exactly how would you describe a leadership behaviour that allowed member divers to conduct very high narcotic potential, significant overhead ceiling dives on a single cylinder and no redundancy, using 30 year old tables?



So, what you're saying is that the club system permits them to do dives that could be "suicidal".

However, some astute and prudent individual members recognise the insufficiency of their club training relative to the dives they are empowered/authorised to undertake.

So those astute and prudent individuals feel obliged to seek supplemental training from outside the club system?

The issue was that CMAS derived clubs were anachronistic and suffered from inertia in their approaches to decompression diving.

If club members are forced to routinely seek more modern and comprehensive decompression training from outside the club, isn't that supportive evidence for what I'm saying?

My primary point is that diving approaches and applications have evolved drastically since the 1950s. What used to be the norm might now be widely considered "suicidal"; but CMAS-derived clubs remain unable to modify their standards, limits and training requirements to reflect that.

I’m quite surprised at your opinion of BSAC, especially as you use it in your marketing signature block.

BSAC is not primarily a training agency, but a diving agency. It's up to the individual where and with whom they do their training. If you read our 2016-2020 strategy document you would see we are moving to support divers to go diving.

As for linking BSAC and CMAS, remember BSAC left them over 20 years ago because they weren't prepared to move with the times. CMAS’ primary function is to support competitive water sports, not non-competitive SCUBA.

BSAC technical training is here which is recommended for dives below 35m.

I do suspect it's our stance on not allowing BSAC training outside a Branch, the Regions or a Centre (school), hence you can't run BSAC courses.

 

[Colliam7]

What I am suggesting is if your shop does not carry a line of gear and the shop does not want you showing/talking about that line of gear then you are in fact not presenting all the facts or options to the student. The student will never know what gear is out there and what may or may not be best for them. They will however most likely go with the "expert" opinion of the instructor.
What I am suggesting is the omission of information can be construed as transmitting subtle messages that certain gear may not be up to par. Because my LDS only stocks the best gear...

OK, fair enough. I understand. Your example really isn't an issue of paid vs volunteer, rather an issue of openness of Instructor communication. Thanks for the clarification.

 

[Colliam7]

For entry level instructor ratings, the clubs usually have higher requirements than PADI and SSI.

Bennno, I don't have any particular body of experience with the club-approach to instruction. So, I am curious, what would be examples of some of these additional requirements? Not disagreeing (or agreeing), just interested in knowing a bit more.

 

[Colliam7]

let me take an example in order to explain what I said: In the States, you have few individuals that turns between 3 jobs back and forward: President of Goldman Sachs type of bank, personal Advisor to the President and then Professor of Economics at Yale or Harvard. When I am looking at what such an individual is doing or saying, I always keep that in mind because he is, by nature proned to be biased. This does not imply that everything that he is saying is wrong or immoral

Thanks for the follow-up explanation! It is very helpful.

I suspect we all attach a perception of some possible bias to any 'source' we might read / hear / use. So, if I hear something from a paid instructor working for a particular shop, or from a volunteer instructor working independently, I see possible bias in the comments of both - IOW, none of us is completely free of the possible influence of our circumstances and environment.

 

[DevonDiver]

.. they have created a whole new category of pushing things. Having hard rules rather than having divers evaluate risk.

That is understandable though, given that their business is 'pile them high and sell them cheap'.

But it isn't just PADI et al that has a structure and limitations on decompression (or overhead)... so do agencies like GUE, UTD, IANTD, TDI etc..

Regarding your 'enabling' clubs to sit in a bunker - taking Nitrox as an example. Nitrox has been on the OW equivalent course since 2007 (at least). No extra courses required.

Noted.

Diving courses should educate people so they can make informed choices. To get a 50m air qualification with BSAC you need to have done.....

I did note before that many non-club divers fail to appreciate the nuances of progressing in a club environment.

Simplistically comparing equivalent qualifications (i.e. Sports Diver with AOW) as a defence of 'recreational' decompression diving isn't a fair or accurate comparison in respect to training and assessment given.

Nonetheless, it is accurate to note that the syllabus and requirements provided, as standard, for divers to achieve these levels doesn't encompass many/most of the key issues contained in a 'proper' tech diving course.

What I don't understand is why that is enabled to persist. BSAC has a formal tech syllabus... why does that run in parallel to sports deco? Why doesn't it replace sports deco?

'Just Say No' is bound to fail, telling people they have hard limits will fail. It isn't better to give people the tools and experience to decide for themselves.

The message isn't 'just say no'.. It's "just get appropriate training, equipment and mindset'.

That training and equipment is readily available around the globe in 2016.

In that respect, people should decide for themselves on the basis of the availability of proper training. It has to be informed decision, reflecting a contemporary mindset and a consensus on necessary practices and approaches.. as reflected by the vast majority of the diving community and industry.

The issue... as per the title of this thread... is what tools are deemed necessary. In the 1960s, that was a single tank and Navy-derived tables. In 2016, the tools have evolved....

 

[DevonDiver]

I’m quite surprised at your opinion of BSAC, especially as you use it in your marketing signature block.

Its all relative. There's good and bad in everything. Noting a weakness relevant to a specific line of debate is not the same as denying strengths.

As for linking BSAC and CMAS, remember BSAC left them over 20 years ago because they weren't prepared to move with the times.

The link is only in respect to a common syllabus/standards policy on enabling sports (non-technical) decompression diving. That policy seems common amongst all of the (many) national clubs that initially derived from or twinned with CMAS.

I can't think of a universal name to describe that grouping of clubs?

 

[KenGordon]

Nonetheless, it is accurate to note that the syllabus and requirements provided, as standard, for divers to achieve these levels doesn't encompass many/most of the key issues contained in a 'proper' tech diving course.

What I don't understand is why that is enabled to persist. BSAC has a formal tech syllabus... why does that run in parallel to sports deco? Why doesn't it replace sports deco?.

Progressive learning. Sports Diver is not for doing 60m 25 minute dives. To do those you need to do ADP, Sports Mixed Gas and Explorer Mixed Gas.

However all the (backgas) elements are there in Sports Diver and those courses build on that. There is a lot on planning and having enough gas for the dive. Of relevance to this thread it is worth pointing out that a single doesn't have enough gas to get into huge deco on a first dive in U.K. conditions, usually I see (singles) people doing the deco on second dives having pushed the first and using air.

Dives start simple and get more complicated with depth and time. You do not need the same gear to do a 28m 25 minute air dive as a 30m 30 minute dive or a 40m 40 minute dive. The risks are different and so the management of risk is different.

 

[Freewillow]

I think that the old fashioned approach is actually the one taken by the big commercial agencies. By categorising deco diving as completely 'other' and having stuff like having to not dive for a period of time if a diver goes past NDL they have created a whole new category of pushing things. Having hard rules rather than having divers evaluate risk.

Exactly. This is laughable. I do not understand why during a sport diving training, students are not pushed, with the right supervision, to go into a small one minute deco obligation. Just in order to find out how their computor would react and what indications are to be followed. This is much better than to have the same experience, on your own and have to try to figure out what your computor is telling you.

To speak about small deco obligation as a "mortal sin" is, for me, stupid. NDL is a "statistical evaluation" of a risk to run into an ADD. This risk is not "your own", it is a statistically calculated risk on a particular population. Everybody is differently sensitive or prone to ADD. Individual A may well be candidate for an ADD by staying within the NDL, while another may end the dive free of ADD, even when not respecting a deco obligation of a few minutes. On top of that computors have safety factors and different brands give different NDL. I am diving with 2 computors everytime. One main and a back up that is the same as my wife. I can easily be with 3 minutes in deco for my main and 3 minutes away from the NDL on the other one......................So what? Am I in deco, or not ?

So what we are doing is to talk about a barrier "NDL" that exist but that is somehow undefined. The whole thing is far from black and white, we are dealing with grey zones and limits. So why put NDL @ 67.5 % of shades of gray when we know that the limit is somewhere between 55 and 70 ?

But it isn't just PADI et al that has a structure and limitations on decompression (or overhead)... so do agencies like GUE, UTD, IANTD, TDI etc..

.

You are mentionning technical agencies. We are in the advanced recreational sub forum.

For my part, I make a clear difference in risk between a small deco obligation and on Overhead limitation. When I was young I used to do dry cave exploration. The "risks" that I faced there just kills any idea to do the same thing under water. I trully admire you guys.

To be alone in OOA with 5 minutes to the cave exit and the surface is not really comparable to OOA @ 5meters deep with a 5 minutes deco obligation. In one case, you are dead, in the other case you are under O2, in a recompression chamber, or with physical problems. Not ideal, nor nice, but managable in most cases.