My journey towards the three stars (3*)

[Germie]

Please lets go back ontopic. Tell you experiences to become 3* or as instructor if you teach 3*.

 

[Colliam7]

Hardly a personal opinion when anchored in scientifically proven, peer-reviewed fact delivered by experts in the field.

https://www.omao.noaa.gov/sites/default/files/documents/Rebreathers and Scientific Diving Proceedings 2016.pdf
Page 69

So, as I interpret your response, the included citation, and your 'Page 69' reference, your basis for advocating use of helium mixes is based on gas density. Thank you for the explanation of the basis for your opinion.

However, since you also reference my comment, I will re-iterate, that what you presented regarding REQUIRED use in recreational dive instruction represents your personal opinion, based on the proceedings document as you reference it. There is nothing wrong with holding that personal opinion, or guiding your diving practices according to that opinion. Nonetheless, it remains your personal opinion.

As with many things in science, the problem, of course, is translating physiologic data to clinical outcomes. And, a possible basis for your statement in clinical outcomes data was the focus of my question.

Yes, gas density increases with depth (actually, with increasing pressure). Yes, work of breathing increases as gas density increases. Yes, air movement during respiration decreases with increasing air density. Yes, hypercapnia is a not entirely unanticipated consequence of severe reductions in air flow during respiration. And, helium is a less dense gas than either oxygen or nitrogen, and diluting air with helium would presumably produce a mix of lower density. All of that is true.

However, there are no simply data supporting the existence of a meaningful number of untoward events occurring during recreational dive instruction, that would have been mitigated by use of a less dense air mix. Nor, do the papers and discussion in the proceedings document even remotely suggest that such a practice - dilution of the mixture with a less dense gas - is required during recreational dive instruction (i.e. it should be illegal to do otherwise). In fact, while acknowledging that the possibility - that 'a diver might not be capable of moving much more gas in and out of their lungs than during normal breathing sitting at rest' - exists, the authors specifically state, 'Such situations would be unlikely to be encountered in properly planned dives'. So, your opinion, that 'air/nitrox diving to anywhere over, say, the mid-thirties metres on air/nitrox should be illegal for an instructor or agency' is simply NOT anchored in 'scientifically proven, peer-reviewed fact'. Such anchoring requires more than isolated physiologic data, it requires demonstration that a) the physiologic data are aligned with some discernible pattern of untoward 'clinical' outcomes, and b) that banning the practice will have a discernible effect on the incidence of untoward outcomes.

If YOU choose to hold that opinion, fine. I now better understand why you might choose to believe that. If you choose to adopt that as personal practice, fine. That is your personal decision, based on your personal opinion. But, to suggest that anything in the proceedings document supports your statement, above, is unfounded.

Those of us who regularly dive - and work, i.e. instruct - at depths in 'the mid-thirties metres' know that work of breathing is increased. We adjust the pace of activities, and the pace of the requirements we place on students, to compensate for that. That is part of conducting the 'properly planned dives' that the proceedings document references. I will even go so far as to say that, if helium cost no more than air, and was as accessible as air, more instructors and divers would probably use it routinely. But, that is not reality. It is expensive, availability is somewhat limited, and it is not essential to safe, and successful dive instruction 'the mid-thirties metres'.

 

[Storker]

another country boatskills are also part of the course.

Up here, dive boat skills is one of the lessons. If you aren't able to serve as captain/boat tender on a normal club-type dive, I strongly suspect you will be considered to not pass that lesson in the 3* curriculum.

 

[admikar]

If we were talking about another setting than scuba, wouldn't you?
"Welcome to pilot training, let me just wrap this accounts receivables-stuff from my day job, and we can crack at it!" comes to mind.

It seems to me that you do not have any aviation training?
Personally, from experience, I prefer an "amateur" with day job, than some hot shot, with airliner flying goal, teaching me flying. Hot shot is in it just to collect hours, not to give you quality instruction.
Same thing is with scuba. My instructor is an old military diver, trimix, rebreather etc etc. Even if he is an "amateur", I prefer learning from him than from some "zero to hero" professional.
As I was told, 3* diver is an instructor without authorization to teach. You will be hold to instructors standards nevertheless.

 

[Storker]

A question for any tech instructors watching this thread:

If you're teaching an intro tech class, do you take your students into deco? A 3* student would probably not have any experience with diving beyond their NDL, so they most probably wouldn't be able to solve any issue underwater without the option to surface if the excrement really should intersect with the ventilation device. I am - obviously - not a tech instructor, but it seems to me that it would be safer to keep my students out of deco, and only requiring them to perform their training dives as if they were owing a fairly significant deco obligation. While requiring the same performance as they'd need to deliver on a true deco dive.

 

[boulderjohn]

Most technical diving programs have a progression from shallow skill dives to simulated decompression to actual decompression. Different agencies have slightly different approaches. TDI for example, gives the instructor decision-making latitude--it is possible for a TDI student to be certified as a Decompression Procedures diver without ever having gone into deco, but that would be unusual. When I taught TDI, I never even noticed that was a possibility until someone pointed it out later.

With PADI, every tech certification through trimix begins with skills in very shallow water--they can be done in a pool. You then progress through simulations until you do dives at the level for which you will be certified. For Tec 50, the last two dives are deco dives at that level, and the instructor manual states in bold type that the instructor should not do those dives until the student has thoroughly demonstrated mastery of the required skills in previous dives.

Those courses have a required number of dives, but those dives are actually minimum numbers. The real requirements are the skills. If the student cannot do an adequate valve shutdown drill during the required dives, then the student must continue doing the dives until he or she can do it. Can you imagine what it would be like if an instructor learned that a former student had died during a dive because of an inability to to perform a critical skill during an emergency, a skill the student had not done well on in class but the instructor had certified him or her anyway?

 

[Storker]

The real requirements are the skills.

Figures.

We're having a couple of the compulsory dives at least thrice. Apparently, some of us aren't performing adequately.

And I vehemently refuse to answer whether I'm the culprit.

 

[Dan_P]

So, as I interpret your response, the included citation, and your 'Page 69' reference, your basis for advocating use of helium mixes is based on gas density. Thank you for the explanation of the basis for your opinion.

Thank you for your answer.

To be clear, you are correct that the basis of my position, is gas density.

However, since you also reference my comment, I will re-iterate, that what you presented regarding REQUIRED use in recreational dive instruction represents your personal opinion, based on the proceedings document as you reference it. There is nothing wrong with holding that personal opinion, or guiding your diving practices according to that opinion. Nonetheless, it remains your personal opinion.

As with many things in science, the problem, of course, is translating physiologic data to clinical outcomes. And, a possible basis for your statement in clinical outcomes data was the focus of my question.

Allow me to be clearer in my referencing - I went the sloppy way and referenced the proceedings document in total, which may in fairness have contributed to any confusion. The proper reference is listed in the chapter I refered to, with the following accreditation:

Anthony TG, Diving re-breathing apparatus testing and standards UK/EU perspective. In: Vann RD, Mitchell SJ,
Denoble PJ, Anthony TG, eds. Technical Diving Conference Proceedings. Durham, NC: Divers Alert Network;
2009, pg. 218-36.

Peer reviewed, presented by, I'll say, leading experts in the field.

You will certainly find the translation to clinical outcomes you're asking for, there.

About the above, from the proceedings document:
Throughout these tests a standard set of endpoints have been used to define 'dive failure' including: (any of) equipment or monitoring failure, diver unable or unwilling to continue because of dyspnoea (shortness of breath) or exhaustion, and an end-tidal CO2 >8.5 kPa (64 mm Hg) over five consecutive breaths. The latter is indicative of significant CO2 retention to a level associated with sudden incapacitation in the diving setting.

To be clear, these trials were carried out in a controlled setting, which is why they could be as valuable as they were - in a less secured setting, they would without a shred of doubt have violated the Helsinki Declaration.

Yes, gas density increases with depth (actually, with increasing pressure). Yes, work of breathing increases as gas density increases. Yes, air movement during respiration decreases with increasing air density. Yes, hypercapnia is a not entirely unanticipated consequence of severe reductions in air flow during respiration. And, helium is a less dense gas than either oxygen or nitrogen, and diluting air with helium would presumably produce a mix of lower density. All of that is true.

However, there are no simply data supporting the existence of a meaningful number of untoward events occurring during recreational dive instruction, that would have been mitigated by use of a less dense air mix. Nor, do the papers and discussion in the proceedings document even remotely suggest that such a practice - dilution of the mixture with a less dense gas - is required during recreational dive instruction (i.e. it should be illegal to do otherwise). In fact, while acknowledging that the possibility - that 'a diver might not be capable of moving much more gas in and out of their lungs than during normal breathing sitting at rest' - exists, the authors specifically state, 'Such situations would be unlikely to be encountered in properly planned dives'. So, your opinion, that 'air/nitrox diving to anywhere over, say, the mid-thirties metres on air/nitrox should be illegal for an instructor or agency' is simply NOT anchored in 'scientifically proven, peer-reviewed fact'. Such anchoring requires more than isolated physiologic data, it requires demonstration that a) the physiologic data are aligned with some discernible pattern of untoward 'clinical' outcomes, and b) that banning the practice will have a discernible effect on the incidence of untoward outcomes.

For the purposes of planning rebreather dives and in the current absence of more definitive or
contradictory data, it seems prudent to recommend an ideal maximum gas density of 5.2 g·L-1 (equivalent
to air diving at 31 m [102 ft]) and an absolute maximum of 6.2 g·L-1 (equivalent to air diving at 39 m
[128 ft]).

Please keep in mind that the human physiology is the same across rebreather and open cirquit diving.
In the words of the author, diving beyond those limits should not be illegal (those are my words), but it would be difficult to interpret it as anything but unprudent.
I would argue that an instructor should at all times act in a prudent fashion.

If YOU choose to hold that opinion, fine. I now better understand why you might choose to believe that. If you choose to adopt that as personal practice, fine. That is your personal decision, based on your personal opinion. But, to suggest that anything in the proceedings document supports your statement, above, is unfounded.

Disagreed.

It seems to me that you do not have any aviation training?

Closest thing was helicopter control officer in a previous life.

Personally, from experience, I prefer an "amateur" with day job, than some hot shot, with airliner flying goal, teaching me flying. Hot shot is in it just to collect hours, not to give you quality instruction.
Same thing is with scuba. My instructor is an old military diver, trimix, rebreather etc etc. Even if he is an "amateur", I prefer learning from him than from some "zero to hero" professional.
As I was told, 3* diver is an instructor without authorization to teach. You will be hold to instructors standards nevertheless.

Absolutely agree with you that a hot shot with a focus on other matters than your training, is undesirable.
I don't mean to redact, but I hope it's clear from my previous statements (if not, allow me to be clear here), that I think my perception of a "low level" in the industry (the professional domain of it, to be clear) is a bigger problem than the level of any amateur out there.
By that I mean "zero to hero" specifically.

To be certain, I see the hunt for a reduced barrier of entry as the root problem in all this.
And to be absolutely certain, that can't be isolated to any one agency.

 

[Storker]

Ocean diving day 2

Day 2 arrived, this time with clear weather and hardly any breeze. Our planned site was about an hour's drive outside town, so as before the day's program started at 8am. We were a mite set back when we arrived at the site, because while we might well be able to park at the site, it didn't seem as if we would be able to get out from the parking site after doing our thing. Long story short, there was a bit too much snow in the parking space along the road.

So we continued driving, albeit at a noticeably slower pace, tailing the car with the instructors. After some ten-fifteen-ish minutes, they turned off from the road down towards the sea.

We arrived at the local wharf in the local industrial area. Didn't look too bad, decent access on both sides of the wharf and only one person fishing from the wharf. Deciding that it's always a good thing to be friendly with the locals, I walked over to have a chat. No, he didn't speak the indigenous language. No, not English either. Neither German nor French. He was Polish. With a fairly suitable combination of English, German and sign language I was able to somewhat convey that we were planning to dive here, but we'd stay well clear of the area where he was fishing. And if he'd be so kind as to stay within "over there" and "over here" with his lures, that would really be appreciated.

The instructors of course took it as a learning experience: you never know if the planned site will be available, so always be prepared to improvise. Yeah, right. Good try.

Anyways, having found a new and possibly suitable site we researched it. Praise be online marine maps and 4G mobile networks. We got a decent idea of the bottom conditions, and started asessing the approachability. Not too bad, we can dive here. Then establishing the site, deciding where to splash and where to place the O2 kit. Coordinates were noted down in case we'd need to call emergency services (not likely, but better safe etc.). We were lucky enough to have a dive leader who wasn't planning to participate diving, but we had to message a couple other divers who were following us about the change of site.

Then it was time to start kitting up. The program of the day was yet another skills dive, yet another instruction dive, the search dive and some not-so-nice surprises. We descended and did a normal dive, one of the students leading. The instructor just observed. Then we were to demonstrate the normal basic drills, this time with higher expectations on behavior. I messed up somewhat on a few details, but luckily one of my buddies was aware and signalled me what I did wrong. All in all, not too bad. After suitable SI, we descended again to do the search dive. Which was complicated by the fact that the instructor had chosen a strongly sloping bottom site for that exercise. So while doing the circular search pattern, I got a yo-yo profile beyond any expectations. Good thing we were all breathing 32%.

When we ascended, our instructor told us - with a noticeable smirk - that "sorry, guys. The boat tender turned out to be a disaster, and the boat is nowhere to see. You've got a km to swim. See that cabin on the other side of the bay? Swim over there and back here, git!" I was like "you're effing kidding, right?" No, he wasn't. So, make sure your wing and your DS are properly inflated, take out the bearing and start paddling. Find the proper pace and make sure you can make it in a good way. Good thing I had a couple of buddies to shoot some crap with while paddling, otherwise it'd be rather boring.

When we got back, there were grilled - or rather, lightly cremated - hot dogs available. That's one of the many good things with club diving: the social aspect is highly prioritized.

Naturally the weather turned a bit nasty when we were kitting down and packing down. Heavy snow and quite a bit of wind. Many of us didn't bother to get out of the undergarments and just got into the car still wearing them. Just as we'd driven to the site in our undersuits. I really appreciated being (fairly) dry as I was watching a couple of freedivers getting out of their wetsuits in the wind and snow. But everybody was rather soaked when we were done packing down, so I had to run the car a few minutes to clear the windshield for fog before I could start driving. Good thing I have a garage and a block heater, so no matter the humidity in my car, it'll be decently dry next time I need to use it. On the way back, I had a couple extra passengers who had come out just to dive while we were doing our class dives. It was interesting to re-experience how they saw the site. For me, it was quite unexciting. For them, it was a really cool dive. Ah, the enthusiasm of youth.

After rinsing down the gear, we had another feedback session. Finally the instructors were willing to take things personally. We all got personal feedback on where our strong points were, and where we didn't perform adequately. I understand that feedback on that level is a high-risk adventure, but dammit, we were all reasonably experienced and reasonably ambitious to be able to accept that kind of feedback a bit earlier.

Another weekend day going 8am-8pm. I'm really getting a little too old for this crap.

 

[Germie]

To answer the question for instructors:

Here deco is a speciality course within cmas. So in the 3* only 2 simulated decodives with smb are done, max depth 30m. I am quite strict, it must be done horizontal and 12 m is not then 10 and then 14. It is a constant depth and +/- 50 cm is ok .
You see that this is for sportsdivers difficult. For techdivers easy. When a technical diver has adv nitrox or higher done with me, i know they can also do real decodives. So I dont have to do another 2 simulated dives, they are done already in the adv nitrox course.
A techcourse also starts in shallows and simulated deco.

But 3* is different from a decocourse, holding a briefing, organising dives as responsable diver is part of 3*. Guiding also.

Here the decompressiondiving specialty is something I dont completely agree with. You do it with only backgas and single tank is allowed. I will never plan decompression diving with only backgas or with just just single tank. So I only sign it off in conjunction with an adv nitrox including deco from another agency.
The advanced nitrox course is also a little bit strange: po2 of 1.4 instead of 1.6.
They know my opinion in the nob about this.

The 1* is changed in a 7 dives course where others do it in 4.
The 2* has 14 modules, and this doesnt mean 14 dives ( some clubs or instructors think that). You can combine and it can be ready with a good diver ( no time to make mistakes) in 5-6 dives, including the ''' ontop' specialty deep. The new 2* has new things like reelwork. And rescue diver is included in 2* now.