Starting PADI Tec-40 - first Tec course, any advice?
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Kevrumbo
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I don't like delaying the introduction of Trimix or two deco gas mixes (50% & 100% Oxygen) until PADI Tec50 (50m/166'): there are very real issues of Deep Air narcosis & inefficient slow tissue off-gassing resulting in type one DCS despite a seemingly normal "textbook" deco profile on Eanx50 only (i.e. excluding an additional 100% Oxygen deco stop for further more efficient slow tissue off-gassing).
An air/nitrox bottom mix maximizes the highest possible fraction of N2 and thereby the largest potential PPN2 ongassing gradient together with an increased Work-of-Breathing effort at the 30 -40m range. So you potentially have real & serious issues of CO2 retention & narcosis due to increased work of breathing upon hard physical exertion, as well as loading up & satrurating your slow tissues with high PPN2, and finally limting a cleaner more efficient decompression by only using EANx50 for deco. For the newly PADI Tec 40 Certification Graduate, two dives a day on such a profile over several consecutive days would be risking a type one DCS event.
All of which can be mitigated in the first place for the beginning Tech Diver -in my honest opinion- by using a proper Triox or Trimix bottom gas along with both 50% & 100% Oxygen deco gases. . .
Training wise IMO/IME, it's better sense albeit more expensive to start using Recreational Triox through Trimix early in your tech deco course progression. You would then have a reference experience of expected "clear-headed" performance to compare against should you choose later to undergo the nitrogen narcosis of Extended Range Deep Air Decompression Diving. (PADI Tec 40 on the other hand uncomfortably starts you initially with Deep Air instead).
The "clear-headedness" aspect is not just only for better appreciation of the aesthetics of the dive, but more importantly to deal with emergency contingencies at depth. In my opinion it is better to learn and practice these vital skills (valve shutdowns; out-of-gas scenarios; primary light failure etc) early and often with Trimix & cognitive clarity, before electively choosing to deal with the potential handicap of narcosis on Deep Air --especially if going into further or future training in deep overheads such as a wreck or cave. . .
An air/nitrox bottom mix maximizes the highest possible fraction of N2 and thereby the largest potential PPN2 ongassing gradient together with an increased Work-of-Breathing effort at the 30 -40m range. So you potentially have real & serious issues of CO2 retention & narcosis due to increased work of breathing upon hard physical exertion, as well as loading up & satrurating your slow tissues with high PPN2, and finally limting a cleaner more efficient decompression by only using EANx50 for deco. For the newly PADI Tec 40 Certification Graduate, two dives a day on such a profile over several consecutive days would be risking a type one DCS event.
All of which can be mitigated in the first place for the beginning Tech Diver -in my honest opinion- by using a proper Triox or Trimix bottom gas along with both 50% & 100% Oxygen deco gases. . .
Training wise IMO/IME, it's better sense albeit more expensive to start using Recreational Triox through Trimix early in your tech deco course progression. You would then have a reference experience of expected "clear-headed" performance to compare against should you choose later to undergo the nitrogen narcosis of Extended Range Deep Air Decompression Diving. (PADI Tec 40 on the other hand uncomfortably starts you initially with Deep Air instead).
The "clear-headedness" aspect is not just only for better appreciation of the aesthetics of the dive, but more importantly to deal with emergency contingencies at depth. In my opinion it is better to learn and practice these vital skills (valve shutdowns; out-of-gas scenarios; primary light failure etc) early and often with Trimix & cognitive clarity, before electively choosing to deal with the potential handicap of narcosis on Deep Air --especially if going into further or future training in deep overheads such as a wreck or cave. . .
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Thank you. If only more instructors had this mindset.
modustollens
Contributor
I did my tech-40 last summer. I spent many months reading and somewhat interviewing potential instructors before deciding who to train with. So, hopefully you have done your homework on this head. I would never just book a course with a dive shop. I made that mistake once before and will not make it again.
During my training we practiced all the skills but there was also a steady stream of emergency scenarios to deal with.
Being able to hover is, as has been said, super important.
And don't forget to turn the right post back on when doing a valve drill
.
I am waiting on the ferry to Koh Tao now and will be there in a few hours - maybe I will see you on one of the boats!
MT
During my training we practiced all the skills but there was also a steady stream of emergency scenarios to deal with.
Being able to hover is, as has been said, super important.
And don't forget to turn the right post back on when doing a valve drill
.I am waiting on the ferry to Koh Tao now and will be there in a few hours - maybe I will see you on one of the boats!
MT
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I don't see how you can avoid it.
Let's take the simple fact that you have to be able to hold deco stops for extended periods of time. That sounds simple enough until you realize you are doing it in horizontal trim. If you can't hover in that position and if you don't have the kicking skills it takes to make fine adjustments to your position as you do so, those deco stops are going to be a frustrating mess. You'll be swimming in circles trying to stay near a teammate. It makes sense to me to work on those skills first rather than try to force people to do what they are not capable of doing by skipping that important work.
I came a similar argument for cave training. The first step for most people is cavern training, and that assumes you have many of those basic skills. I have heard cave instructors say they can teach those skills while they are teaching the full cavern skills. I haven't seen them try, but I find it hard to believe. It seems to me that cave instructors could benefit by offering a basic skills workshop prior to cave instruction for those who need it.
This discussion is precisely why I push and push the GUE Fundamentals class for people who are considering going on to tech or cave training. Learn the basic skills in shallow open water . . . then you can really focus on what's important in your next phase of training.
I don't think anyone should present for a tech or cave class who can't hover in place and do the Basic 5. But that is not to say that doing that is easy -- it's just that the work to get to that point can be done by anyone, and does not require an instructor, just some background information and some diligent practice.
I don't think anyone should present for a tech or cave class who can't hover in place and do the Basic 5. But that is not to say that doing that is easy -- it's just that the work to get to that point can be done by anyone, and does not require an instructor, just some background information and some diligent practice.
CptTightPants21
Contributor
The sticking point for me is that many people go into tech training, cave, wreck or deco, not knowing if the expectation may be there that they know how to do "basic 5" or equivalent before they get there. And in very few classes is horizontal trim etc taught in OW.
In the normal OW/AOW/Rescue path of scuba training, the instructor teaches you what you need to show or do in each class. There is no assumption the OW student knows how to clear a mask.
The expectation therefore becomes that the tech instructor will do the same thing: introduce the new concepts like basic 5 so students can practice. If the instructor at an introductory tech class like AN/Deco assumes the students already have this, and the students have no idea of this expectation, I believe a disservice is occurring. A student should know ahead of time what will be taught and what they need as a prerequisite. Otherwise it's a cart before a horse kind of thing.
Once you get to more advanced tech courses, certainly the prerequisite of basic 5 should be expected.
It's precisely because most OW/AOW divers are not taught these things in class, as evidenced by many postings on SB, that I suggest the intro to tech or Fundies class may be needed.
In the normal OW/AOW/Rescue path of scuba training, the instructor teaches you what you need to show or do in each class. There is no assumption the OW student knows how to clear a mask.
The expectation therefore becomes that the tech instructor will do the same thing: introduce the new concepts like basic 5 so students can practice. If the instructor at an introductory tech class like AN/Deco assumes the students already have this, and the students have no idea of this expectation, I believe a disservice is occurring. A student should know ahead of time what will be taught and what they need as a prerequisite. Otherwise it's a cart before a horse kind of thing.
Once you get to more advanced tech courses, certainly the prerequisite of basic 5 should be expected.
It's precisely because most OW/AOW divers are not taught these things in class, as evidenced by many postings on SB, that I suggest the intro to tech or Fundies class may be needed.
GUE Fundamentals was created as a class to take prior to taking the cave classes. That was a good idea. I think such classes ought to exist in all agencies. There is a class like that in the PADI set of courses, but it is a Distinctive Specialty only taught by a handful of instructors. My last tech student had taken that class prior to taking his tech program, and he was very solid from the start and breezed through the tech class.
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