Advice about mixed gas training please [Archive]

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mickybobthediver

25-11-2007, 18:25

I’m thinking of taking the following BSAC courses:
Advanced Nitrox Diver (AND), followed by Extended Range Diving (ERD), followed by Sports Mixed Gas (SMG).

Would this lead to a recognised qualification?
Is it equivalent to anything offered by the IANTD or other training agencies? In other words, would the training be recognised?

What kit configuration would I need?
I imagine that I might need a twinset (and wing). Would I need to upgrade my computer to one that can cope with mixed gases or are trainees encouraged to carefully plan their dives with (software) tables and slates?

Even though these courses are open to those with a Sports Diver ticket, I intend to increase my experience to beyond the 100+ dives that I’ve already done. But advice gleaned here will help me make plans (book courses, keep my eye out for good deals on kit etc.).

Your comments and suggestions would be welcome.

JamesW

25-11-2007, 18:45

Have a word with Mark Powell http://www.dive-tech.co.uk/

Thanks

Gareth

25-11-2007, 22:01

Mick

It's quite a jump to do Advanced Nitrox (AN), Extended Range Diving (ERD) & then Trimix.

The AN & ERD courses are both currently being re-written.
The current AN format is a bit dated now, which is why it is being to be re-written. In it's current format the limitations are quite large when compared to other agency courses. Although it depends what you want from the course. The existing course does not require twinsets.

The ERD course is being re-written to act as a better feeder for the Trimix courses. There has been a swing away from deep air diving, with most agencies encouraging people to use Trimix at depths in excess of 40m (some recommend shallower). The ERD course requires Twinsets to be used (& stages). Mixed gas computers are not required, in fact all the diving is done on runtime (hard tables).
It is possible to combine the ERD course with a Sports mixed gas course.

Trimix is a definate step up. There are generally Three trimix courses, Sports, Normoxic, & Hypoxic.

I would suggest you check the postion of the AN & ERD courses in the new year. The Diving Officers Conference is next weekend (1 December). It is expected that we will get an update on the progress of the technical group with all the technical course. So, we should know what new courses are being released, what courses have been replaced with re-written courses, which course will be re-written in the next 12 months. There may also be changes to pre-requesits for course etc.

ERD & Trimix diving is about discipline, planning & exceptional diving skills, especially bouyancy.

You need to get a good competent instructor who will stretch you. They should be doing this type of diving regularly.

You should also be aware that these are not attend & pass courses. Infact, if your skills are not up to the standard required you may well be stoped part way through the course.

Gareth

Chris Cherrington

26-11-2007, 10:42

The BSAC Sport Mixed Gas is pretty much like a normoxic trimix as offered by IANTD or TDI. (I think the BSAC one is at least as good if not better). As Gareth says its a fair old leap up from SD. In terms of recognition this is only important for the next level of training. In BSAC this is Advanced Sports Mixed Gas. I have little doubt if you wanted to progress with IANTD/TDI/PSA they would accept your BSAC "Normoxic" as a perfectly good start point to "advanced trimix".

In your position I would start to look at twin cylinders as the next move and I would suggest a twinset familiarisation course with a good technical instructor rather than learning in the club environment. This will give you a broader perspective than just seeing things "the BSAC way". From that point on though the BSAC trimix courses are every bit as good as the IANTD/TDI/PSA etc.. Just be aware that the BSAC Advanced Nitrox is only half the course of the technical agencies' advanced nitrox, which is why you need ERD as well. You need to therefore view those two courses as a single unit in terms of progression.

I'd also agree with James that a chat with Mark Powell is a good start point as he is an instructor for TDI/PSA and BSAC and a pretty good guy in this field.

Chris

Steve in Sharm

27-11-2007, 18:52

Steve in Sharm

27-11-2007, 19:01

In your position I would start to look at twin cylinders as the next move and I would suggest a twinset familiarisation course with a good technical instructor rather than learning in the club environment. This will give you a broader perspective than just seeing things "the BSAC way". From that point on though the BSAC trimix courses are every bit as good as the IANTD/TDI/PSA etc..

Good advice, actually they are better than TDI.

Just be aware that the BSAC Advanced Nitrox is only half the course of the technical agencies' advanced nitrox, which is why you need ERD as well. You need to therefore view those two courses as a single unit in terms of progression.

I'd disagree there, true the BSAC AN is 2 days whilst the TDI is 3 - but this is due to the fact (IMHO) that TDI are actually playing catchup to BSAC. BSAC divers already know about PPO2, Tables which include 'Deco' and indeed deco diving - whilst TDI is having to teach from scratch its PADI crossovers (ok my arguement falls down with the number of dives, but take into account a BSAC divers prior formal training in this area and it is easy to see why we dont need as many dives).

Regards

Steve

JamesW

27-11-2007, 19:11

TDI is having to teach from scratch its PADI crossovers

Why ?????

Steve in Sharm

27-11-2007, 19:28

Why ?????

OK from scratch was a bit harsh, but your typical PADI diver who decides to 'go techy' has, at best, only done PADI Nitrox - no deco theory, no deco practical - twin singles/twinsets! forget it. So TDI have to include more stuff in their course syllabus that BSAC have already covered in the divers SD course.

Regards sheepy

Steve

Alwassia

28-11-2007, 08:25

Ok here is were i feel i have to put in my 5 cents,
I started out with PADI and then going to BSAC before becoming interested in the deeper longer staff. Due to the lack of qualified TDI, BSAC, IATND ... instructors the only choice i had was the DSAT route.
The things i liked was that in 2 courses you went from air diver to full Trimix.
The first was Tech Deep Diver, 8 days of hard mental and physical work. 12 dives in total i think, not counting the repetitions i had to do. That was the most demanding course i have ever taken. Now i could dive to 50 meter with air as back gas and lots of deco tanks doing accelerated deco.
What i liked is that you did the course and got what you wanted, at least that was the case for me.
Then after 18 month and many dives i wanted to give Trimix a try. Once more i had to choose DSAT for the same reasons.
Again a hard course with lots of theory and demanding practical application of the things learned. Ahh i forgot i did lots of dives during the course as well.

Now there are horses for courses, that is the same in Trimix courses.
I wanted to do the tihing in one go and not over three four steps like some of the other Tech Agencies. If you like the same then DSAT is a very good option. ( but i think that you can break each of the 2 course in halv as well)
The course material was very good in all aspects. Safety aspects where enforced to the point that i dreamed about them and my wife started asking questions.
On the other hand the courses are expensive, especially if you need to buy or rent equipment, as they cover material which is distributed over several course with other agencies in one go.
The bad thing is that the initial Trimix certification is to 75m, where DSAT then say progressive build up dives lets you go further but not specifying how far. Which is interpreted by others as a 75m absolute limit - communications is key i guess.

If you have not so much cash at hands and or not so many free days then splitting up the material in many smaller bit may be better.

Having read the course reports on TDI, BSAC and INATD i think that the skills and knowledge at the end are very similar just the way how to get there is different. Remember there are many roads which lead to Rom, but all get you there. The mattra that the instructor is more important then the agency cont as well on the Trimix level.

As i said earlier just my 5 cents.

Khaled

DAFFY

28-11-2007, 10:57

Neither does the TDI one - in fact you can also do their deco procedures and ERD courses on a single cylinder (though you at least need an 'H' valve for the ERD).

Regards

Steve

Sorry steve, I may be misunderstanding your post. Are you saying that you can do the TDI deco prod course on a single cylinder (albeit with a H valve) or the BSAC ERD course

tootricky

28-11-2007, 14:04

(I think the BSAC one is at least as good if not better).
Good advice, actually they are better than TDI.
What makes you say that?

Chris Cherrington

28-11-2007, 14:28

What makes you say that?

The BSAC SMG courses are the very latest in the sense that they were written recently (last year). As such they incorporate all the latest thinking on what is happening in the technologies and skills developments. There are no quirky weird BSAC things in them, the deco regimes are via third party software (decoplanner) with open acceptance of other deco tools. To my mind they take the best bit of BSAC (the pragmatic what work, works, view) and leave behind some of the outmoded things found in many other courses (both BSAC and non-BSAC)

As with any course the instructor is a very big factor. But one can only be encouraged to see people like Mark Powell in the UK or Tekstream in Dahab choosing to teach these courses, giving both an endorsement of the content and the chance for BSAC divers to use some of the best in the business without needing to take an IANTD or TDI course. (Not that there is anything wrong with either of them)

I re-joined BSAC in order to take the Advanced SMG course. I am, generally, not easily impressed...

Chris

Gareth

28-11-2007, 14:52

Daffy

I think Steve is refering to the TDI courses.

The BSAC ERD catagorically requires a Twinset.

Gareth

Steve in Sharm

28-11-2007, 17:11

Yep, the TDI Deco proc course allows you to use a single cylinder with an 'H' vavlve, as does the TDI ERD......

Steve in Sharm

28-11-2007, 17:14

What he said....

JamesW

28-11-2007, 17:23

Yep, the TDI Deco proc course allows you to use a single cylinder with an 'H' vavlve, as does the TDI ERD......

Dual outlet valve or twins.
Thanks

Steve in Sharm

28-11-2007, 19:01

Dual outlet valve or twins.
Thanks

Uh! :confused:

No twins required - single (as in one) cylinder, fitted with an 'H' valve (dual outlet), is the minimum requirement for the TDI ERD course. You dont even need this 'H' valve for the TDI AN or Deco Cse.

Which obviously puts the BSAC courses ahead of the TDI.....

Regards

Steve

JamesW

28-11-2007, 20:13

Uh! :confused:

No twins required - single (as in one) cylinder, fitted with an 'H' valve (dual outlet), is the minimum requirement for the TDI ERD course. You dont even need this 'H' valve for the TDI AN or Deco Cse.

Which obviously puts the BSAC courses ahead of the TDI.....

Regards

Steve

No BSAC 50% TDI 100%, you can do the TDI ADV EAN as an openwater diver.

Anyway what does a mars bar muncher know:D

PeteM

29-11-2007, 07:09

There are no quirky weird BSAC things in them

Apart from their approach to long hoses:D

tootricky

29-11-2007, 11:06

The BSAC SMG courses are the very latest in the sense that they were written recently (last year). As such they incorporate all the latest thinking on what is happening in the technologies and skills developments. There are no quirky weird BSAC things in them, the deco regimes are via third party software (decoplanner) with open acceptance of other deco tools. To my mind they take the best bit of BSAC (the pragmatic what work, works, view) and leave behind some of the outmoded things found in many other courses (both BSAC and non-BSAC)

As with any course the instructor is a very big factor. But one can only be encouraged to see people like Mark Powell in the UK or Tekstream in Dahab choosing to teach these courses, giving both an endorsement of the content and the chance for BSAC divers to use some of the best in the business without needing to take an IANTD or TDI course. (Not that there is anything wrong with either of them)

I re-joined BSAC in order to take the Advanced SMG course. I am, generally, not easily impressed...

Chris
Sounds fair enough. Can you give examples of what you consider outmoded in other courses? I did my TDI Normoxic Trimix with Mark Powell last year, but as I have done all my tech training with him I am not really in a position to compare course content.

Cheers/Nic

Mike Rowley

29-11-2007, 11:10

Apart from their approach to long hoses:D

Would you care to explain that please Pete?

Mike

Steve in Sharm

29-11-2007, 11:20

Apart from their approach to long hoses:D

What? You mean like the SMG and AMG course minimum requirement of a 1.5m hose on your occy????

mickybobthediver

29-11-2007, 15:40

tootricky

29-11-2007, 15:57

I have found the contributions to this thread very helpful - thank you ;). I never knew H valves even existed.

The 'take home' message seems to be that I need to get myself onto a twinset familiarisation course with a good instructor. And then the different agencies are pretty comparable, the quality of the instructor tipping the balance.

I was toying with the idea of a GUE/DIR Fundies course because of its apparent emphasis on fundamental skills such as buoyancy. Now, I think my buoyancy is pretty good (though I do think it can be fine-tuned somewhat) but this has come with experience - the princples were taught and then I was left to learn from experience (which I guess is typical). On this is an ongoing process.

Do people think a GUE/DIR course would be a waste of cash and do you think I could get the equivalent buoyancy assessment/training from a good instructor when I do a twinset familiarisation? Indeed, I get the impression that GUE principles are being adopted by other agencies anyway?

I know this is a slight departure but it seems to me that the basic skills need to be 'tip top' before going onto more advanced diving.

Thanks again.
GUE-F is a good course and you can gain a great deal even if you do not intend to progress to the Tech or Cave qualifications. I did GUE-F before my Trimix course and was glad I did. That said, many of GUE's prinicples are not exclusive to GUE. The difference is the emphasis placed on those principles. For example, you would not fail a TDI course because you didn't have poor trim but you would fail GUE Tech 1. Good trim will help with shutdowns, though, and is to be encouraged :) You could do far worse than do a course with Mark Powell, he is a TDI and BSAC tech instructor and offers twinset familiarisation courses, a twinset can be supplied, IIRC.

Cheers/Nic

Richard Whitcombe

29-11-2007, 17:04

Would you care to explain that please Pete?

Mike

OK rephrase a bit.

Have BSAC got over its rabid phobia of primary donation with a long hose ?

Or as i suspect do they just want a long hose octopus and not primary donate?

Also unless its changed dont BSAC limit ppo2 1.6 to using 100% oxygen at 6m (thereby not using 50% at 21m or 80% at 10m and so on) ?

Those were the only "BSACy quirks" i was aware of before that made me do it with another agency - are these still an issue ?

(genuine question not trolling here)

Paul Duckworth

29-11-2007, 17:39

OK rephrase a bit.

Have BSAC got over its rabid phobia of primary donation with a long hose ?

Or as i suspect do they just want a long hose octopus and not primary donate?

Don't know but doubt it - rabidly as paranoid as a rabily paranoid thing probably.

Also unless its changed dont BSAC limit ppo2 1.6 to using 100% oxygen at 6m (thereby not using 50% at 21m or 80% at 10m and so on) ?

Those were the only "BSACy quirks" i was aware of before that made me do it with another agency - are these still an issue ?

(genuine question not trolling here)

From the Members section, BSAC website (http://www.bsac.org/page/736/safe-diving-o.htm#partial)

Oxygen partial pressure (Technical diving)

When mixed gases and nitrox are being used the partial pressure of oxygen (pO2) should not exceed 1.4 bar for each mix used for either travel (descent and ascent) or bottom phases.
For divers holding recognised qualifications, the pO2 for a depth less than or equal to 6m during the decompression phase must not exceed 1.6 bar. All divers who do not hold a suitable qualification should not exceed a pO2 of 1.4 bar for any chosen gas mix.

Mike Rowley

29-11-2007, 20:07

Have BSAC got over its rabid phobia of primary donation with a long hose ?

Or as i suspect do they just want a long hose octopus and not primary donate?

Not a phobia and certainly not rabid, rather evidence based and logical policy.
Long hose is fine, primary take is fraught with a number of difficulties which have been picked over numerous times. It is just a system that does not work readily and easily in all circumstances, furthermore it requires retraining whereas AAS with long hose works in all circumstances reasonably well whether OC or rebreather and requires no retraining. It makes sense to choose the one that works in all circumstances and that people already know.

Also unless its changed dont BSAC limit ppo2 1.6 to using 100% oxygen at 6m (thereby not using 50% at 21m or 80% at 10m and so on) ?

Again, evidence based policy, why ignore the evidence? The incidence of CNS symptoms is statistically greatly increased when the PO2 increases above 1.6bar. All agencies with the exception of GUE quite sensibly teach the practice of reducing PO2 progressively when adverse factors are involved such as cold water, exercise, lower visibility levels and other stress risers. In addition at 1.6bar a relatively small change of depth may increase the PO2 significantly above 1.6bar. Incidently, the correct SI term is PO2 not ppo2.

Mike

Richard Whitcombe

30-11-2007, 00:07

So basically then no.

Without starting the long hose debate again (suffice to say i strongly disagree with the bsac view here),BSACs position hasn't changed.

As for the pO2 1.6, i wasn't on about using higher values but simply BSAC ONLY allow it at 6m depth (therefore 100% O2) and don't allow the same for other gases deeper (21m/50% and so on) thereby limiting somewhat the choice of decompression gas and profile.
Im not aware of any evidence about an increased risk with this practice and certainly other agencies aren't changing their policies over it.

Anyway, thanks for answering my questions so at least i know where BSAC stand - my reasons for doing an equivalent course elsewhere are to me at least, still valid as a result.

PeteM

30-11-2007, 07:19

Not a phobia and certainly not rabid, rather evidence based and logical policy.
Long hose is fine, primary take is fraught with a number of difficulties which have been picked over numerous times. It is just a system that does not work readily and easily in all circumstances, furthermore it requires retraining whereas AAS with long hose works in all circumstances reasonably well whether OC or rebreather and requires no retraining. It makes sense to choose the one that works in all circumstances and that people already know.

But ignoring which is better long hose debate, BSAC is out of step with just about all the other technical agencies who are either happy or positively encourage the use of Hogathian configuration (despite BSAC being quiet happy with AIR2s etc). Therefore it is a quirk of the BSAC system (one of the definitions of quirk being "aspect of personality").

Ultimately all training agencies have their own quirks (one reason I have had training from three agencies). I think it behoves anyone getting advanced training to be aware of these quirks and to make their own informed judgement on the issues and dive in the way they think best

Chris Cherrington

30-11-2007, 09:42

... do you think I could get the equivalent buoyancy assessment/training from a good instructor when I do a twinset familiarisation? ....

Yes, but with a few caveats.

The GUE courses are pretty intensive and you get videoed and a lot of attention. That costs money. TBH you can get the buoyancy element from a PADI PPB course (and you can do it with twins and a HOG setup).

The GUE course will give you lots of other stuff for your 300 quid or so. Fining techniques, ratio deco etc. If you want them too do it. Many of us cherry-pick the best ideas from DIR without doing the whole thing (much I think to their annoyance).

Chris

Chris Cherrington

30-11-2007, 09:46

Sounds fair enough. Can you give examples of what you consider outmoded in other courses? ..

Things like PADI's irrational snorkel use or FFESSM still doing buddy breathing. I've only done cave stuff with TDI so I can't comment on their course content TBH.

Chris

Chris Cherrington

30-11-2007, 09:54

Mike Rowley

30-11-2007, 12:43

But ignoring which is better long hose debate, BSAC is out of step with just about all the other technical agencies who are either happy or positively encourage the use of Hogathian configuration (despite BSAC being quiet happy with AIR2s etc). Therefore it is a quirk of the BSAC system (one of the definitions of quirk being "aspect of personality").

Actually most training agencies do not specify Hogathian rig or any other rig come to that, most leave it entirely to the instructors preference. Most instructors find Hogathian rig convenient since it is easy to re-stow after deployment for demonstartion. Even I have been known to loop it after a demo, even whilst using a rebreather. Re-stowing isn't a major issue for non-instructors.

BSAC might be happy with AIR2s and octopus rigs at recreational level but I can assure you that Tech Group was never happy with these configurations. Neither would be acceptable on BSAC Technical courses. Even where a rebreather has an AutoAir fitted to comply with BS EN 14141 BSAC Technical courses insist on an adequate off-board bailout system.

Most training agencies are just that, training agencies. They are not responsible for the subsequent diving whereas a members club is, therefore the members club has a right and duty to specify some base standards for it's diving operations.

Amongst BSAC Tech Group there were considerable discussions about which technique to adopt as a standard. The issue was not cut and dried or a matter of dogma, some favoured one approach, others dissagreed. In the end it came down to an evidence based descision. We looked at the evidence as understood by each of us, as put forward by various people and publications, we considered views from this and other forums and carried out some water based trials then endevoured to reach a logical, evidence based solution.

I apologise in advance that this is a long post but I would like to lay out the reasons that led to the reccommendations.

There are a number of facts that cannot be ignored when considering the efficacy of configuration and technique. These are the facts that were considered by BSAC Tech Group when they evaluated the evidence before making a reccomendation on which technique to adopt. I am not making an argument here, merely explaining the basis on which the reccommendation was made.

Fact. Hogathian rig with primary take will work adequately in straight forward scenarios and does have the benefit of ensuring that the gas the recipient receives is breatheable and the regulator can be conveniently re-stowed when no longer required.

Fact. Hogathian rig is a neat and convenient method of stowing a long hose when used by divers conditioned to primary take. It has minimum drag and small potential for snag.

Fact. Since we now have some divers who are conditioned to primary take procedure all divers must be trained to cope with a panicking diver taking a primary regulator from their mouth.

Fact. Hogathian rig with primary take does not work at all and is potentially dangerous to both divers when a rebreather is involved, either as the donor or the casualty. I am informed that there has been an incident this year where a diver attempted to take a rebreather divers mouthpiece in an out of gas situation, an inevitable eventuality I'm afraid.

Fact. Rebreathers cannot be ignored when considering technical diving techniques since they are increasingly prevalent amongst technical divers and are now the equipment of choice for serious technical divers. A technical diver can no longer assume that he/she will never be in the same bit of water as a rebreather diver. This is becoming a fact of life for recreational divers too.

Fact. Hogathian rig with primary take requires a significant element of retraining since all agencies bar one teach AAS at recreational level.

Fact. Hogathian rig with primary take is less convenient and requires some donor input to make it work in less straight forward scenarios. When the casualty approaches from the left, from below or from behind the donor has to make modifications to his/her position to make the procedure work. This necessarily involves some significant retraining and practice to make this efficient and autonomous. It is not impossible but does require considerable retraining and practice.

Fact. It is a sensible precaution if using Hogathian rig with primary take to wear the mask strap under the hood to ensure mask is not dragged off in deployment. No one suggests that this is an innevitable consequence or even a significant risk but it is a potential problem.

Fact. AAS with bungied long hose works with all configurations, including rebreathers. It is necessary to ensure that the AAS is conspicuously and conveniently positioned and other innapropriate gases are not positioned as to be mistaken. However, as most technical divers (including rebreather divers) use side mounted stages with regs bungied to the stages this should not be a problem or involve any modifications to already learned techniques. With back mounted stages this issue becomes more complex.
With independent twins (a perfectly valid equipment choice as long as rule of thirds discipline is observed) the logical solution is to utilise long hoses on both back gas regs with the out of use reg at any given time positioned in a convenient and conspicuous place. With isolation manifold twins two long hoses cover all eventualities but if one is preferred then the logic is to breathe the short hose with the long hose available as redundant or AAS.

Fact. AAS with bungied long hose does not require any significant retraining, just careful configuration. Divers coming to technical diving will already be familiar with this technique.

Fact. AAS with bungied long hose does not require the donor to modify his/her position to make the procedure work efficiently. The hose should deploy reasonably efficiently regardless of direction of approach.

Fact. Long hose with AAS does not require the mask strap to be worn under the hood as a precaution to prevent it being dragged off in deployment.

Fact. AAS with bungied long hose has minimal drag and snag potential, similar to Hogathian rig. However, re-stowing after use is not convenient or easy.

An additional consideration was that if BSAC adopted Hogathian rig with primary take then the logic is that this technique should be adopted from entry level recreational diver and taught throughout to establish a common technique in what is an emergency skill set that must be common, autonomous and efficient. It was generally accepted that there could be significant risks with teaching this technique at entry level.

The concensus of opinion after much discussion and some water trials was that the facts that AAS worked reasonably efficiently with all equipment types, in all circumstances, did not require any significant donor technique modification in unique circumstances and did not require any significant retraining outweighed the advantages of Hogathian rig with primary take.

My personal view is that this is the logical conclusion. You may dissagree and are entitled to do so but there it is. My purpose with this post was to show that we gave this matter careful consideration and set out the salient factors that were considered, not to re-open old debates. Evidence based evaluations can hardly be called a "quirk" and something is not necessarily the most efficaceous technique just because many adopt it. Many drivers hog the middle lane on a motorway, that doesn't make it the best technique.

I have explained the issue of PO2 and the reasons we came to the recommendation we adopted in detail previously on this forum. To be brief we took note of statistical evidence provided by the chief diving scientist at QuinetiQ and this informed our conclusions. We do allow a PO2 of 1.6bar at depths deeper than 6m where used as a bailout gas for rebreathers to facilitate the widest possible depth range for each gas and use in a variable semi-closed mode emergency ascent. In these circumstances the diver will be exposed to 1.6bar PO2 for minimal time.

Mike

tootricky

30-11-2007, 17:28

Fact. Hogathian rig with primary take does not work at all and is potentially dangerous to both divers when a rebreather is involved, either as the donor or the casualty. I am informed that there has been an incident this year where a diver attempted to take a rebreather divers mouthpiece in an out of gas situation, an inevitable eventuality I'm afraid.

Fact. Hogathian rig with primary take requires a significant element of retraining since all agencies bar one teach AAS at recreational level.

My personal view is that this is the logical conclusion. You may dissagree and are entitled to do so but there it is. My purpose with this post was to show that we gave this matter careful consideration and set out the salient factors that were considered, not to re-open old debates. Evidence based evaluations can hardly be called a "quirk" and something is not necessarily the most efficaceous technique just because many adopt it. Many drivers hog the middle lane on a motorway, that doesn't make it the best technique.
Thanks, I will :) In the first fact I have highlighted above you state that primary donate is potentially dangerous for both divers if a rebreather is involved. I agree if an OC diver goes for a RB divers primary but in the other case it is no more risk than primary donate on OC. RB diver comes off loop and takes/receives primary reg. The second fact is misleading. Whilst I can believe that, in some cases, significant retraining is required, in many cases it is not. I would be interested to know if you have any figures to back up this claim?

Still, disregarding those points, I am sure you would still reach the same conclusion based on the others. It is refreshing to see that a great deal of thought has been put in to these matters :)

Mike Rowley

30-11-2007, 17:56

I agree if an OC diver goes for a RB divers primary but in the other case it is no more risk than primary donate on OC. RB diver comes off loop and takes/receives primary reg.

Good point and you are quite right however, I would suggest that this is an unlikely scenario since a rebreather diver would have his/her own bailout (unless he/she dives alpinist) therefore would be self sufficient. Two problems would need to occur simultaneously for this to arise, not impossible but unlikely I would suggest.

The second fact is misleading. Whilst I can believe that, in some cases, significant retraining is required, in many cases it is not. I would be interested to know if you have any figures to back up this claim?

This assumption is based on the fact that all bar one recreational training agency teaches AAS at entry level therfore retraining is required to teach the new skills related to primary take with Hogathian rig. To do this thoroughly the instructor would need to teach coping which scenarios where the casualty approaches from the left, below or behind and where the donor must act quickly to make the procedure work. Once taught these skills will need to be practiced regulary to become automatic.

I would also add that my experience and that of some other instructors is of students mostly being familiar with AAS but not that many have been conversant with Hogathian rig and primary take. It depends whether the student has received training from a previous instructor who teaches this skill set or if they come direct as a recreational diver. However, I concede that I haven't pressed the point since I don't teach this unless the student is adamant that they prefer it.

Mike

PeteM

30-11-2007, 18:40

Actually most training agencies do not specify Hogathian rig or any other rig come to that, most leave it entirely to the instructors preference. Most instructors find Hogathian rig convenient since it is easy to re-stow after deployment for demonstartion. Even I have been known to loop it after a demo, even whilst using a rebreather. Re-stowing isn't a major issue for non-instructors.

Mike I am not arguing for or against primary donation all I am saying is that it is a quirk of the BSAC technical courses that this is banned whereas I believe every other agency doing technical training allows it. No where on this thread have I said that is a good thing or a bad thing just that it is something we do differently

Mike Rowley

30-11-2007, 20:21

Mike I am not arguing for or against primary donation all I am saying is that it is a quirk of the BSAC technical courses that this is banned whereas I believe every other agency doing technical training allows it. No where on this thread have I said that is a good thing or a bad thing just that it is something we do differently

Agreed Pete although I would not call it a quirk, rather a considered recommendation.

Things may change though as NDC Technical Group has been reconfigured under Sean Gribben. It now has a new leader and there is a new Tech Chief Examiner and Tech Chief Instructor. They might decide to change the recommendation although I haven't heard anything to that effect.

Mike

Chris Cherrington

01-12-2007, 08:15

Mike I am not arguing for or against primary donation all I am saying is that it is a quirk of the BSAC technical courses that this is banned .....

I've had long discussions on this and I don't agree that primary donation is banned. BSAC simply takes the view that their instructors should not teach it. They may do it, explain it and even demonstrate it, but not teach it.

Chris

TerryH

01-12-2007, 13:20

An additional consideration was that if BSAC adopted Hogathian rig with primary take then the logic is that this technique should be adopted from entry level recreational diver and taught throughout to establish a common technique in what is an emergency skill set that must be common, autonomous and efficient. It was generally accepted that there could be significant risks with teaching this technique at entry level.

I work on a more simplistic, number crunching reason.

How many lives have been saved worldwide by using a long hose/primary
donate, in bog standard recreational diving. Not caves, not inside wrecks,
nothing special, just ordinary diving. I bet you'd struggle to even get into
two figures in a decade, let alone a year.

Now imagine the number of certs per annum. One million would be an
underestimate. Bear in mind that each course would need about 8 primary
donates to become even remotely confident.

So you have an absolute certanty of 8 million primary donates and a
percentage where dispite an Instructor being present, there will be a
serious problem vs an extremely small (and unknown) number that this
technique would save.

I've got no probs with long-hose/primary donate as set out in Mikes post,
but we really do need to be realistic and make it relevant to who is going
to use it. It's an absolute fact that 95% of the worlds divers average 20-30m
stuff on a warm-water holiday, being towed round by a DM.

No matter how better the system is in a cave etc. it will never be the 5%
who can dictate to the 95%.

When you also consider that unless you are psychic, when starting you dont
know that you will be in that 5%.

The real danger IMO is senior divers/Instructors promoting this system at
entry level when they cant possibly gauge if that student is going to do cave,
wreck etc. Ok if they stay in there club, but what happens if they do
become a holiday diver? Not too difficult to imagine them in the Red Sea
with a problem and ripping out the reg of a standard occi diver.

Recreational = Keep it simple.
Once past that, do what you want.

Steve in Sharm

01-12-2007, 13:29

Mike Rowley

01-12-2007, 15:26

Scary, I agree with him......

On another point.

Have just checked the depth limits in the SDP book and forund 80m as the absolute maximum for technical dives - has this been upgraded since the introduction of the AMG course - cos I can se a lot of dissolusioned bunnies hopping over to TDI to get that magic 100m...

Sports Mixed Gas (recreational) = 50m
Sports Mixed Gas (Technical) = 60m
Advanced Mixed Gas = 80m

The 80m depth rating was arrived at because this was felt to be the limit at which a diver could participate as a self sufficient diver carrying all his/her gas and equipment with them. Beyond this depth we considered in-water support and more complex surface support is required.

The plan was to introduce a further level of Expedition Mixed Gas which would not have any depth limit. This course would involve all of the support strategies necessary for the extended decompression schedules of deeper dives.

I don't know what the progress is on this latter course since I am no longer involved, it was scheduled to be introduced at DOC this year but Tech Group has changed considerably since the change of NDO.

Mike

MattS

01-12-2007, 16:43

Chris Cherrington

01-12-2007, 18:42

........

Recreational = Keep it simple.
Once past that, do what you want.

Its hard to think of anything more simple than primary donation. I will however concede its the minority. The arguments against it are largely flawed IMO and certainly not reason enough to have it in the new BSAC technical courses.

I'm very happy to follow the herd in early training though and Terry is right 90% or so of divers are 20m divers under tow from a DM. So standardisation is the way to go and makes sense. So get that AAS on the right please..... ;)

Chris

Steve in Sharm

01-12-2007, 19:29

So get that AAS on the right please..... ;)

Chris

left, Left, LEFT,

if we achieve nothing but this, please let us educate the masses that AS (AAS) should be on the left......

Steve

TerryH

01-12-2007, 19:45

So get that AAS on the right please..... ;)

I get the smiley which should mean left, but shame on you Chris,
we all should know it's an AS not an AAS :rolleyes:

Mike Rowley

02-12-2007, 14:27

I've had long discussions on this and I don't agree that primary donation is banned. BSAC simply takes the view that their instructors should not teach it. They may do it, explain it and even demonstrate it, but not teach it.

Chris

I would be interested to know who gave you this advice and when Chris? Up to July of 2007 the Technical Chief Examiner (Person responsible for instructor standards) would definately not have taken this view. The view taken would be that explaining and demonstrating constitutes teaching and therefore would not be an acceptable thing for a BSAC instructor to do. It specificaly states in the mixed gas instructor manuals that primary take may not be taught.

Mike

Nigel Hewitt

02-12-2007, 15:10

It specificaly states in the mixed gas instructor manuals that primary take may not be taught.Fair enough.

I would still be upset if a mixed gas course didn't make you aware of it and prepared for it as it is a common enough procedure. If you are diving with a non-BSAC trained diver who has a gas problem you can expect them to act as they were trained rather than, in a moment of crisis, remember that you are BSAC trained and adjust their desperate grab for something to breathe to the right one of your secondary and two stage regulators.

Mike Rowley

02-12-2007, 16:01

Fair enough.

I would still be upset if a mixed gas course didn't make you aware of it and prepared for it as it is a common enough procedure. If you are diving with a non-BSAC trained diver who has a gas problem you can expect them to act as they were trained rather than, in a moment of crisis, remember that you are BSAC trained and adjust their desperate grab for something to breathe to the right one of your secondary and two stage regulators.

I would agree Nigel. I think BSAC teaches how to cope with a diver taking ones primary reg in DTP now does it not?

I'm not quite sure how you teach people to cope with someone taking your rebreather mouthpiece other than fight em off and give them your OC bailout. It comes to something if we have to teach people to cope with innapropriate emergency techniques though.

Something I have often thought since the mixed gas courses were written, given an OC diver ran out or had insufficient travel or deco gas and none was available from surface or in-water support and few divers would have a AAS on their stages, gas sharing becomes the only alternative to an inacurate ascent. Given that gas sharing is no longer taught at DTP level we should consider including this skill at technical level.

Mike

Mike

Nigel Hewitt

02-12-2007, 18:26

I'm not quite sure how you teach people to cope with someone taking your rebreather mouthpiece other than fight em off and give them your OC bailout. It comes to something if we have to teach people to cope with innapropriate emergency techniques though.I think that one is less of a problem as the differences between a twinset and a rebreather are more impressed on their minds. I have heard this has happened but I'd love to hear details from the parties involved.

I have, for an experiment, tried an ascent using an Inspiration equipped buddy's Auto-Air and it was not fun. After a couple of glitches he dumped his wing via the 'pull to dump' system and did drysuit buoyancy from then as the dump button just connected me to the wing.

Something I have often thought since the mixed gas courses were written, given an OC diver ran out or had insufficient travel or deco gas and none was available from surface or in-water support and few divers would have a AAS on their stages, gas sharing becomes the only alternative to an inacurate ascent. Given that gas sharing is no longer taught at DTP level we should consider including this skill at technical level.Admittedly the only time I have ever done a buddy breath was on the wonderfully DM kit swap exercise. Conversely that is one of the nice things about the CCR. You can have all my bailout gas. It is calculated to get me out from any dive I will undertake and statistically your chances of getting it are good as I have never needed it yet. It's that moment when you are heading for me having just exhaled and got nothing (or worse water) that we have to get over first. Psychologically it must be very bad. I do quite a bit of freediving but I'll bet a mouthful of sea would make my relaxed breath hold time go from minutes to seconds.

Mike Rowley

02-12-2007, 18:52

I have, for an experiment, tried an ascent using an Inspiration equipped buddy's Auto-Air and it was not fun. After a couple of glitches he dumped his wing via the 'pull to dump' system and did drysuit buoyancy from then as the dump button just connected me to the wing.

So have I, it wasn't impossible but it was extremely difficult. In a distress situation it would be well nigh impossible, certainly very prone to fail. That is why there is not one fitted to my rebreather.

Mike

Michael Purcell

02-12-2007, 21:53

Fact. Since we now have some divers who are conditioned to primary take procedure all divers must be trained to cope with a panicking diver taking a primary regulator from their mouth.

Is it primary take or primary give? I know in my GUE course I was taught to donate not to take. (and there is a big difference) Having said that...

In our club one of our AD/AI got in a very serious circumstance. Even though she is BSAC all the way and (at that point) had never been exposed to primary donate, guess which one of her buddy's regulators ended up in her mouth? And guess what she is diving today.

(Isolated cases don't get us anywhere, but neither does mis-information.)

Chris Cherrington

03-12-2007, 08:43

I would be interested to know who gave you this advice and when Chris? Up to July of 2007 the Technical Chief Examiner (Person responsible for instructor standards) would definately not have taken this view. The view taken would be that explaining and demonstrating constitutes teaching and therefore would not be an acceptable thing for a BSAC instructor to do. It specificaly states in the mixed gas instructor manuals that primary take may not be taught.

Mike

Well I would take the view demonstration is not teaching. I've had the argument for/against with you Mike, on here and gained the impression its OK to do but don't teach it. The instructor manual states "Primary donation is not a recommended practice for BSAC mixed gas diving" (p 157) - not it is banned (nor even you can't teach it if I were to be pedantic). The only other person I've spoken to is Jeff Reed and again my chat with him reinforces my view.

I think we can all agree that primary donate is not a suitable method for 90% of divers, this is no reason to ban it any more than banning the crazy christmas tree multiple regulators pony and AIR2 set ups you see on a good many club divers...

Chris

Mike Rowley

03-12-2007, 10:36

[QUOTE=
(Isolated cases don't get us anywhere, but neither does mis-information.)[/QUOTE]

What exactly are you suggesting here, that I have been giving mis-information which is usually a euphomism for mendacity?

If this is the case and I hope it isn't, I find your comment offensive. I have no problem with anyone dissagreeing with me but I do not appreciate insults and inuendo as a form of debate.

Mike

Michael Purcell

03-12-2007, 11:22

Sorry I wasn't taking issue with what you had said. (It was good to see a rational even if I don't agree with it.)

When I referred to isolated incident I was referring to MY example. And when I was taking issue with primary TAKE, I don't believe you were the only one using that term. It was the term primary TAKE that I had issue with.

(and if primary TAKE was a decision factor for discarding primary donation I TAKE issue with that.) :)

And since BSAC is far less presecriptive than GUE we are left to make our own decisions about what to keep and what to discard.

Mike Rowley

03-12-2007, 11:29

Well I would take the view demonstration is not teaching. I've had the argument for/against with you Mike, on here and gained the impression its OK to do but don't teach it. The instructor manual states "Primary donation is not a recommended practice for BSAC mixed gas diving" (p 157) - not it is banned (nor even you can't teach it if I were to be pedantic). The only other person I've spoken to is Jeff Reed and again my chat with him reinforces my view.
Chris
The actual wording under the heading of Kit Configuration and kit up is:

Primary donations is not a recommended practice for BSAC mixed gas diving since it is not compatible with:
The basic training and methods taught throughout the BSAC Diver Training programme.
Some equipment configurations and types.
Rebreather diversThe BSAC believes that it is advantageous to stick with a system that works for all equipment types and configuration, doesn't require any significant training or adaptation to be compatible with mixed gas diving, is compatible with divers previous training at recreational level and so keeps things simple.

Hogarthian rigging (Hog wrapping) has the benefit of ease of re-stowing, however, it is designed for primary donation which does not work for all equipment types. There is a danger of fouling the donor diver's regulator when "hog wrapping" is not used in conjuction with primary donate. It clearly does not work when an out of gas diver approaches from the rear or from the wrong side.

The regulator which the diver wishes to make available to an out of gas diver should be stowed prominentlyand identified in the buddy check, have a long (approximately 2 metres) hose which is best stowed either under cord or rubber banding on a cylinder or in the wing ties.

That seems pretty clear on what instructors should teach and the policy of BSAC to this issue and in this course. I agree that it doesn't actually state "do not teach primary donate" but neither do we state "do not teach negative buoyancy deep rescue technique" or "air sharing" any more but both techniques are no longer part of BSAC training. It does clearly state the techniques a BSAC Mixed Gas instructor should teach.

I would have taken the view that explaining followed by demonstartion is teaching, not the most complete teaching experience but never the less teaching. The current Tech Chief Examiner may take a different view, I don't know.

Mike

Mike Rowley

03-12-2007, 11:33

IainC

03-12-2007, 11:45

Michael Purcell

03-12-2007, 11:48

Michael Purcell

03-12-2007, 11:56

I'm interested in this don't teach thing..

If a student asked me (on the boat, in the car park, wherever) what primary donate was for example (and it has happened) - I can't just say 'we don't teach it', that doesn't help them. I would to explain (& maybe demonstrate, 75% visual and all that) it to them so thay can see what it was. Towing the official line and my personal prefernce, I'd follow that with 'I don't use it,BSAC don't recommend it ..blah blah... cave diving ...blah blah .. but it is useful to know in case you come across it somewhere'

I have just explained and demonstrated something (hence taught it) - is it only the nature of the explanation (basically, 'don't do this..') that makes the difference?

Iain.

Perhaps it has to do with what "hat" you are wearing. *shrug*

It's tough because if I am not an instructor then there is no question I can demonstrate as I like. But if I am an instructor am I able to step out of the role of instructor and give the benefit of my knowledge or am I bound by a "teacher" persona.

Mike Rowley

03-12-2007, 12:15

I'm interested in this don't teach thing..

If a student asked me (on the boat, in the car park, wherever) what primary donate was for example (and it has happened) - I can't just say 'we don't teach it', that doesn't help them. I would to explain (& maybe demonstrate, 75% visual and all that) it to them so thay can see what it was. Towing the official line and my personal prefernce, I'd follow that with 'I don't use it,BSAC don't recommend it ..blah blah... cave diving ...blah blah .. but it is useful to know in case you come across it somewhere'

I have just explained and demonstrated something (hence taught it) - is it only the nature of the explanation (basically, 'don't do this..') that makes the difference?

Iain.

Ian

Don't take my view as gospel, I have no official position now and the new Cheif Examiner may take an entrely different view.

The position I took was that this technique may not be taught by a BSAC Technical instructor whilst teaching a BSAC mixed gas course. The techniques to be taught are those stated in the instructor manual.

Outside of the course an individual can discuss or demonstrate what he/she wants. However, I would expect a BSAC instructor discussing such a technique with a diver as an individual to put the pros and cons in an impartial way and point out the club policy with the reasons for it.

Mike

IainC

03-12-2007, 12:21

Outside of the course an individual can discuss or demonstrate what he/she wants. However, I would expect a BSAC instructor discussing such a technique with a diver as an individual to put the pros and cons in an impartial way and point out the club policy with the reasons for it.

That sounds sensible to me.

Iain.

Chris Cherrington

03-12-2007, 12:47

Chris,

I think you are stretching the limit to meet your argument. They have discounted "hog wrap" as incompatable with BSAC standards you can't turn around and then use "demonstrate" as a back door.

(IMO)Hopefully there will be some pressure to change this but ignoring or substituting our better judgement isn't a way forward.

Personally, I have seen the (IMO) *irrational* venom from a certain NI instructor towards the "hog wrap"...

I think TBH we are arguing about semantics. Hogarthian is not incompatible with BSAC standards. It's not the start point for training (nor should it be).

The set up is named after Bill (Hogarth) Main and relates to cave diving.

As someone who occasionally cave dives its my usual set up. Its a primary donation set up. I would expect to have to demonstrate it to anyone with whom I was doing a buddy check. Is that teaching it? Does my status as a just a buddy or as an instructor make the difference?

Mike is primarily a RB diver and lucky enough to have some wonderful diving on his doorstep that isn't caves. Grabbing a RB loop and flooding it isn't going to get an OOG diver the gas they need but it will spoil the RB diver's day. I understand that and the reticence of many folk to accept primary donation. It makes sense. There is no implied criticism on my part - each to their own. What works, works - that's the best of BSAC tradition.

I am not putting it forward as the way to go or the preferred option or better or any such thing.

It worries me that I see here (and elsewhere) the view that primary donation is not allowed. It is. I think that is now the consensus position of everyone on this thread. Demonstrate vs teach is still up for debate.

Chris

Michael Purcell

03-12-2007, 13:43

I think TBH we are arguing about semantics. Hogarthian is not incompatible with BSAC standards. It's not the start point for training (nor should it be).

I would like clarification on this. It definitely is a grey area in our club. There are those that argue that it is in fact not compatible with BSAC standards. Just as we cannot teach buddy breathing.

The set up is named after Bill (Hogarth) Main and relates to cave diving.

Nice history lesson :)

As someone who occasionally cave dives its my usual set up. Its a primary donation set up. I would expect to have to demonstrate it to anyone with whom I was doing a buddy check. Is that teaching it? Does my status as a just a buddy or as an instructor make the difference?

I also do a bit of cave diving and maintain my configuration in the open water. For me I believe it is the most productive configuration (for me). And the bolded part really is the point isn't it. There are those of us that dive it in the BSAC model then BSAC divers need to be aware of it if they are going to dive with us. It seems incompatable to say the instructor cannot teach the method, even if it is only taught as an alternative that is not supported in the BSAC implementation but they will encounter in many technical environments.

Mike is primarily a RB diver and lucky enough to have some wonderful diving on his doorstep that isn't caves. Grabbing a RB loop and flooding it isn't going to get an OOG diver the gas they need but it will spoil the RB diver's day. I understand that and the reticence of many folk to accept primary donation. It makes sense. There is no implied criticism on my part - each to their own. What works, works - that's the best of BSAC tradition.

I really think this rebreather argument is a red-herring. I dive with MCCR divers regularly and the only way I would rip the loop (even in my first dive with them) would be in blind panic. As I have suggested in my example earlier I am not sure that when fear turns to panic that training and muscle memory really overcome the knowledge that the reg in the mouth is the one supplying breathable gas.

It worries me that I see here (and elsewhere) the view that primary donation is not allowed. It is. I think that is now the consensus position of everyone on this thread. Demonstrate vs teach is still up for debate.

Chris

While many of our club members are diving a DIR configuration the feeling really is that the primary donation is a problem for BSAC. (Not that we are turned away of course...) Anyway, interested to seehow the debate pans out...

Janos

03-12-2007, 18:06

I emailed HQ about this two years ago.

I asked:

I was has having a discussion with someone the other day about BSAC's policy towards donating the primary regulator in an Out Of Air Situation - ie the one that the donor is breathing from.

My understanding is that BSAC have forbidden teaching "donate the primary" to trainee divers (a view I agree with) but that there is no reason why experienced divers should not breath the long hose on a club trip.

Is my understanding correct?

The response I received was:

You are right in your assumption, that in all BSAC training for AAS out of air scenarios, the Instructor Manual recommendations should be followed.

Alternative techniques as you describe are not forbidden, however the BSAC view is that this is an advanced technique that should only be considered for adoption for say dive leaders with suitable confidence and experience. A thorough buddy pre-dive brief is obviously essential for this.

Using the method with BSAC divers still under training may cause confusion.

I think that explains it very clearly to me, and I have not seen any updates since (my email was originally in September 2005), so I continue not to have any issue with people breathing the long hose.

I think it's also silly to use a technique that is not practiced, so when I breathed the primary, I would practice with my experienced buddies grabbing it unexpectedly (in shallow water). I would be uncomfortable doing this with inexperienced divers.

When teaching OD or SD divers, I would thread the (stuffed, long hosed) octopus through a loop of surgical tubing on my right-chest d-ring, and breathe the short hose.

Janos

Michael Purcell

03-12-2007, 19:47

Thanks that was helpful...

Of course I have issue with the:

I think it's also silly to use a technique that is not practiced, so when I breathed the primary, I would practice with my experienced buddies grabbing it unexpectedly (in shallow water).

not that you practice it but I still feel that a panicked diver is (just as likely)going for the known good regulator regardless of the donation method so one should expect (practice) losing their primary regulator regardless of configuration.

Janos

03-12-2007, 22:21

not that you practice it but I still feel that a panicked diver is (just as likely)going for the known good regulator regardless of the donation method so one should expect (practice) losing their primary regulator regardless of configuration.

I agree (I think :D). IMHO most of the raison d'etre for breathing the long hose is "that's the one they'll go for anyway" so it makes sense to practice for that event. I have issues with teaching "primary grab" to trainees, but for experienced divers I think it's ok.

Janos

Mike Rowley

04-12-2007, 15:14

I agree (I think :D). IMHO most of the raison d'etre for breathing the long hose is "that's the one they'll go for anyway" so it makes sense to practice for that event. I have issues with teaching "primary grab" to trainees, but for experienced divers I think it's ok.

Janos

Apart from the logical arguments surrounding this issue which many of its adherents prefer to ignore, choosing to follow anecdotal "evidence" over logic, has anyone actually looked at the statistics relating to out of gas incidents to see how frequently people in this situation go for the regulator in the donors mouth?

If the facts confirm that this is indeed the case It would certainly justify a review of the policy on this issue. To date I have seen no statistics to support this view and on ballance the logic is against the practice.

Mike

Michael Purcell

04-12-2007, 16:03

As I said I only have anecdotal evidence and gut feeling. Neither of which should dictate policy. Of course it isn't clear cut and perhaps BSAC does in fact have it right. Mind you it seems to me primary donate does seem to be coming a bit of a defacto standard with the tech agencies.

As for the re-teaching that would be required I called my GUE instructor on the lack of an intro to scuba course put on by GUE. Why allow another agency to teach them only to "teach them the GUE way" afterwards. (cost, development, instructors, etc) Having said that if you look at their safety record and what they accomplish (exploration-wise) they seem to be doing something well.

It doesn't mean that BSAC does it any less well but as a "newer" entry in defining "what tech means to us" I feel they should try to gather data to support a decision that was heavily biased in favour of the choice they made.

I'm really not criticizing just trying to talk it through to get myself in some sort of "buy-in" frame of mind.

Mike Rowley

04-12-2007, 16:46

As for the re-teaching that would be required I called my GUE instructor on the lack of an intro to scuba course put on by GUE. Why allow another agency to teach them only to "teach them the GUE way" afterwards. (cost, development, instructors, etc) Having said that if you look at their safety record and what they accomplish (exploration-wise) they seem to be doing something well.

GUE is a relatively minor player even in the technical diving world which is in itself a minority activity. In the UK there are probably lass than 250 true technical divers and they have moved to rebreathers long ago. I am currently putting together an exped to dive a wreck with a max depth of 145m and every one of the potential divers is a rebeather diver.

If you look at how many of the original WKPP group are still diving and how many are still healthy I think you might want to rethink their safety record. Few of the early mix divers have got away without resididual health problems due to to both syptomatic or aesymptomatic DCI. Many of the early decompression models used we would now consider extremely aggressive.

It doesn't mean that BSAC does it any less well but as a "newer" entry in defining "what tech means to us" I feel they should try to gather data to support a decision that was heavily biased in favour of the choice they made.

I recall that the incident reports were looked at when we considered this matter but can't remember the figures. However, since in the general diving world primary donate is in a small minority and is a divergence from standard practice overall I would have thought that the proponents of this technique are the ones who need to provide solid evidence to justify it. If it is the better technique then it should be adopted universaly as a common standard. What we have at the moment is a campaign by a group of adherents to impose it by stealth and without providing evidence to justify it that can be challanged.

In a utopian world all the agencies would get together and agree a common policy based on logic and evidence then all teach similar techniques such that all divers know what to expect when things go wrong. To some extent this has happened with recreational training. Most technical agencies do not specify the techniques to be used with the exception of GUE and BSAC, the others have very poor instructor manuals or non at all in some cases and leave it to the instructor. Generally it is not a good situation in my view.

Mike

Janos

04-12-2007, 18:05

Hi Mike,

I think you and I can debate the long-hose or not for hours. I always find it funny that in some debates I'm seen as pro-long hose (I'm in favour of giving advanced divers the option) and in others anti (I'm very much against teaching it from scratch).

However, for me, this is not about debating which is the optimum way of storing your octopus, it's about whether we as a club want to be prescriptive or not. To me, one of the great things about BSAC is that generally we don't insist on one particular way. Instead we generally teach people all the different ways that are commonly used, explaining the pros and cons of each, and we train THINKING divers who can assess the evidence in front of them and come up with their own decision that is appropriate to them and the diving they do.

Janos

Mike Rowley

04-12-2007, 18:29

However, for me, this is not about debating which is the optimum way of storing your octopus, it's about whether we as a club want to be prescriptive or not. To me, one of the great things about BSAC is that generally we don't insist on one particular way. Instead we generally teach people all the different ways that are commonly used, explaining the pros and cons of each, and we train THINKING divers who can assess the evidence in front of them and come up with their own decision that is appropriate to them and the diving they do.

Generaly speaking I would agree with you Janos and I have always followed this priciple as a technical instructor. However, I have also taken the view that there needs to be some commonality in emergency techniques and I think this is such an issue. In an ideal world the diving community would look at the available evidence, look at the logical efficacy of various emergency techniques then adopt techniques that work the best for all eventalities where that is possible. What this debate usually ends up with is various people taking polarised positions based upon personal preference, agency allegence or anecdotal "evidence". My view is that we should always take a pragmatic view of these matters and look at the logic and the evidence.

When we discussed this technique we did debate it long and hard. Some were for it, some against and some ambivilent. After looking at all of the available evidence the ballance of opinion came down in favour of AAS. It certainly wasn't a descision based on dogma, paranoia and it wasn't rabid as some have tried to label it.

It may be that evidence will emerge that will change peoples views, if solid evidence did emerge I would certainly be prepared to change my views. I haven't seen any yet but like I said, it is not a matter for me now and new people might take a different view to me. As long as any stance is backed by logic and evidence I will be content.

Mike

Mike

clivethediver2

05-12-2007, 11:01

Hi all.
With reference to Mike's Exped Trimix Course,this was mentioned at DOC by Nick Jewson-but as work in progress-and I didn't hear him say of a date for the course to go live.
Clive

Mike Rowley

05-12-2007, 14:10

Hi all.
With reference to Mike's Exped Trimix Course,this was mentioned at DOC by Nick Jewson-but as work in progress-and I didn't hear him say of a date for the course to go live.
Clive

It was announced at last years DOC by the then Tech Group Leader that the Expedition Mixed Gas Course would be launched at this years DOC along with the revised ERD and the revised Mixer Blender course. Things have changed a lot since then.

The revised Advanced Nitrox course is pending the writing of accelerated decompression tables for the BSAC 88 tables by Tom Hennesey.

Mike

IainC

05-12-2007, 14:33

The revised Advanced Nitrox course is pending the writing of accelerated decompression tables for the BSAC 88 tables by Tom Hennesey.

Mike

I hope these revised nitrox tables are going to include a wider/different range of mixes than 27, 32 and 36? Otherwise they won't offer much?

I would think they need 30% for bottom gas at least (35m MOD on deco dives) and probably 35% as well (30m MOD)

I've seen some relatively neat IANTD printed tables for accelerated deco, I am sure the data would fit into nitrox 88's (by adding extra rows on the deco stop bits - one for deco on bottom mix, another row for deco on 50% 80% etc.).

Iain.

Nigel Hewitt

05-12-2007, 15:19

The revised Advanced Nitrox course is pending the writing of accelerated decompression tables for the BSAC 88 tables by Tom Hennesey.Just when we thought BSAC was moving out of the dark ages BSAC 88s reassert their grip on our throats.

Oh well... When you sell your soul it really stays sold doesn't it?

Mike Rowley

05-12-2007, 16:06

I hope these revised nitrox tables are going to include a wider/different range of mixes than 27, 32 and 36? Otherwise they won't offer much?

Don't know Ian.

I've seen some relatively neat IANTD printed tables for accelerated deco, I am sure the data would fit into nitrox 88's (by adding extra rows on the deco stop bits - one for deco on bottom mix, another row for deco on 50% 80% etc.).

As I understand it, you can't mix the two since they are based on entirely different models. 88s are based on critical volume model I think whereas IANTD is based on an arterial bubble algorithm, not absolutely sure about this but the 88 tables are the only tables I am aware of based on critical volume model.

Mike

Mike Rowley

05-12-2007, 16:14

Hewitt]Just when we thought BSAC was moving out of the dark ages BSAC 88s reassert their grip on our throats.

I think it is a matter of cost. commissioning new tables was looked at but discarded as too expensive. Similar for licensing agreements on existing tables. Cheaper to commission an accelerated table to use in conjunction with 88s. Doesn't really matter since most people will use a nitrox computer and it only applies to Adv. Nitrox which was still regarded as recreational diving. ERD was planned to utilise Pro-dive Planner or any other proprietry software for the course as are the mixed gas courses.

We will have to wait and see what transpires.

Oh well... When you sell your soul it really stays sold doesn't it?

A bit harsh Nigel!:(

Mike

Janos

05-12-2007, 16:16

There's always Deco on the Pie:

Using Air and 50%, I came up with some rules that sort of mimic Bulhman with 20/80 Gradient Factors. Well I think they do. Have a look at see if I'm right.I could be wrong. Indeed I probably am.

Remember, this is for Air and 50%, in the range 20m to 40m.

Rule 1) Always do a three minute stop at 6m
Rule 2) Always do a 1 minute stop at 18m (the Pye stop) and switch to 50%
Rule 3) The "Pie time" at 30m is 20mins
Rule 4) For every 5 minutes above this, do 5 mins of deco
Rule 5) For every 3m deeper (shallower) add (subtract) 5 mins to the pie time.
Rule 6) If you're deeper than 30m, and staying longer than 30mins, then add on a couple of minutes extra "for luck" deco
Rule 7) Roughly 3/4 of your deco is at 6m
Rule 8) Roughly 2/3 of the rest is at 9m
Rule 9) If you're doing more than 20mins of deco, then do 1min stops every 3m from the Pye stop up.
Rule 10) If you're diving below Sports Diver depths (ie 36m plus) then you will need to add in super-Pye stops at 21m.
Rule 11) If you calculate that you need more 25mins of deco, or so, then you're out of the range of rules 1 to 10.

Example: 35mins at 33m

Pie time at 30m is 20mins
So pie time at 33m is 15mins.

Therefore (35mins - 15mins) = 20mins of stops.
Add a couple "for luck"
Gives 22mins of stops.
3/4 of this is at 6m; so 16ish.
Remainder is 6mins. 2/3 of this is 4mins so 9m stop is 4mins
1 min at 18m (the Pye stop) leaves 1min left so...

1 min at 18m
1 min at 12m
4 mins at 9m
16mins at 6m

Whereas Bulhman 20/80 gives 1@18, 2@12, 3@9, 15@6 so we're there or thereabouts.

Janos

[1] - Named after Richard Pye, a lover [2] of fish pie.
[2] - Yes. That sort of fish pie. Allegedly.

Janos

IainC

05-12-2007, 17:19

As I understand it, you can't mix the two since they are based on entirely different models

Ooops, ambiguous post, sorry.

I didn't mean insert the iantd tables into the 88s - I know they are based on different models!

I meant I thought the extra deco data for accelerated deco as calculated in these new tables would fit neatly into the '88format.

The IANTD? ones are the only plastic, 'stick in your pocket' accelerated deco tables I have seen.

Still don't think the tables as they stand are much use for accelerated deco though, so why bother revising them? Why not just promote computer based tables (as the ERD course did) and have done?

Iain.

Michael Purcell

05-12-2007, 17:47

I think the frustration of the 88 tables (aside from age {vs new developments in deco thinking}) is the black-box nature of them. I know if I was doing the following dive I would like to follow the BSAC tables (and be drinking tea on the surface) but would be a little concerned about why everyone else were nowhere to be seen for quite a while. (did I screw something up?)

Dive 51m
26min

BSAC 88
21mins deco (+3min)

Buhlmann (20/85)
75 mins deco

Buhlmann (10/90)
68 mins deco

VPM
102 mins deco

Mike Rowley

05-12-2007, 19:43

Still don't think the tables as they stand are much use for accelerated deco though, so why bother revising them? Why not just promote computer based tables (as the ERD course did) and have done?

Iain.

I believe it is because they didn't want to have to spend time teaching the use of software derived tables and complex run time discipline on what is a course for recreational divers. This is not tech nitrox and is not designed as a feeder for technical courses, it is aimed at recreational divers who wish to use nitrox for its benefits and to accelerate deco.

Mike

Chris Cherrington

06-12-2007, 09:02

My understanding was that the 88s are used (as opposed say to Buhlmann which are free) for insurance liability issues. They (88s) have a great layout and are easy to understand. The new accelerated deco 88s (08s ??) should follow in that tradition. Like the PADI RDP they are a great teaching tool. It makes sense to me to show accelerated deco on the same tables use to teach basic diving.

I'm all for it. (Just don't use them for diving)

Chris

IainC

06-12-2007, 09:33

I believe it is because they didn't want to have to spend time teaching the use of software derived tables and complex run time discipline on what is a course for recreational divers. This is not tech nitrox and is not designed as a feeder for technical courses, it is aimed at recreational divers who wish to use nitrox for its benefits and to accelerate deco.

Mike

Fair enough, simple tables are needed then (and a word of caution for when they all go out and buy gas-switching nitrox computers).

I just hope they come up with a nice, useable solution.

Iain.

Michael Purcell

06-12-2007, 15:02