When I dived the Oriskany, that's what I used. I planned for only 1 deco gas. I ran plans for 50%, 60, 70, 80, 90, and 100% O2. 70% gave me the shortest total runtime.
Tech through PADI or TDI?
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When I dived the Oriskany, that's what I used. I planned for only 1 deco gas. I ran plans for 50%, 60, 70, 80, 90, and 100% O2. 70% gave me the shortest total runtime.
Yes, I remember that. Weird but effective on that dive.
Both RAID and UTD have recreational helitrox/ Trimix.
It's not really surprising. Getting off the bottom gas for the 12m stop can gain more than an extra 10% O2. Similarly for the 9m stop vs 30% extra.
SB posters seem to choose gases for reasons other than minimising stop time.
This subthread 'novice deco divers should have perfect buoyancy' assertion i disagree with. Everyone makes mistakes, especially with new skills and equipment. It is a reasonable mitigation to use a more forgiving gas because some people will actually make the mistake and drop a couple of metres on a stop. Better to risk that with 10 minutes of air stops at 6m on 50% than directly jumping to a gas where it might hurt.
"A gas solution to a skills problem?"
Just kidding, I agree that there needs to be some allowance made for likely student errors when it comes to training and post-cert qualifications. Where to draw that line becomes pretty tricky once you factor in the variables in student performance, instructor performance, course standards etc etc.
Of course, there is then the argument of whether making tech diving more accessible to those of lower skill levels is a desirable thing.
Just kidding, I agree that there needs to be some allowance made for likely student errors when it comes to training and post-cert qualifications. Where to draw that line becomes pretty tricky once you factor in the variables in student performance, instructor performance, course standards etc etc.
Of course, there is then the argument of whether making tech diving more accessible to those of lower skill levels is a desirable thing.
Scuba diving is perhaps the most libertarian thing that we do. "there are no scuba police" speaks loudly to the fact that we enjoy the ability to hurt ourselves through poor judgement to a greater degree than we are used to. I hope that never changes. There is no way to make diving "fool" proof. I see people often thinking that there is some rule based safety protocols that protect people. There aren't, there are only guidelines and suggestions. Rules imply enforcement.
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DevonDiver
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More training = Better Skills.
In a 4 (min) dive course, how much reliability and consistency is able to be achieved?
I'm accounting for the 'human factor', as you gain in experience and training the skills you have become more ingrained... your responses become more reliable and you risk of screwing up declines.
Yes, my courses are significantly longer than the minimum, I put an emphasis on maximising in-water hours with the student... and I push the standards as high as the student can tolerate (with stress causing a barrier to effective learning).
Nonetheless, would I say that every Tec40 student graduates as an INFALLIBLE technical diver? Of course not... that'd be ludicrous.
Yes... ludicrous. That's something you start to appreciate only when you've gained significant (000's or 0000's) of tech diving experience.
Nonetheless, entry-level tech is what it is... and it's not extended range or advanced trimix..
Each step upwards raises the penalties and consequences of getting it wrong.
Tec40 is still very forgiving of errors... and that's very prudent for entry-level tech divers.. who may (with some instructors) have less than 4 dives tech experience, or fewer than 3-4 hours of in-water training.
Why not? What's the rush?
Those capable of doing so can progress directly on to Tec45 (AN/DP equivalent) and further.
Those that need more practice and/or experience have opportunity to do so, before attempting the next course.
I marvel at how some novice tech divers seem to rush into quite unforgiving dives.... there's some severe over-confidence in that attitude.
One characteristic shared by all my tech students is a humility and prudence in their development. You wouldn't hear them complaining about not being allowed to dive deep enough, or with enough decompression, or with X, Y or Z gasses..
The quality of a good tech course is evident when it shows students how fallible they can be.. and how they can easily screw up, especially under realistic and extraordinary pressures...
If a tech course fails to inspire that attitude, or understanding, it was probably a really crappy course...
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DevonDiver
N/A
Because, as an instructor, you are certifying them as competent to carry out a given level of diving.
Does it not seem pretty hypocritical to hand out plastic cards certifying someone at a given level, then desperately plead with them to NOT to conduct dives at that level?
It seems damned hypocritical to me...
But hey... wink wink, nudge nudge... the student is probably just gonna go out and do whatever they want... up to the limitations of their new card and what dive operators sanction.Right?
So everyone wins with TDI.. The instructor hands out shiny cards but has to counsel some students NOT to do those dives (ethical doubts thus alleviated)... and the student gets a card that empowers them to leap onto into very unforgiving, high consequence dives that, sooner or later, Mr Murphy will join upon..... but hey,. . bangs for the bucks.. when it comes to paying for training courses, right?
What protects us as divers are education, guidelines that include limits and the good judgement to follow those guidelines and to know our own limits. We see bad results when divers leave their safety up to someone else or when they allow arrogance to trick them into thinking they know more than they do. My OW instructor left a lot to be desired but the best cliche that he passed along was, "you are your own scuba cop". That is what keeps me from going to 130 feet without further training or diving trimix because "how hard could it be"?
Different agencies break it down in different ways but in the end, there is a body of knowledge and experience that we need to gain. c-cards don't give us those things, they only serve to protect the instructor and the agency. I wouldn't consider them adequate to judge competency, at, all.
Certifications make it appear to be a set of stairs but it isn't really. It is handy to break it up into steps and we can argue about where those step should be and how many there should be but in the end an instructor and a student have a body of knowledge to convey.
I intend to build a relationship with my instructor where he teaches me in the way that makes sense. He will leap ahead and he will fall back based on what makes sense. I will dive based on what I understand and based on a reasonable progression of experience. How that aligns with agency certifications isn't as important as what he has been able to teach me and show me.
There will be certifications but they will simply be a convenient way for me to release him and whichever agency from liability and that is the reason for all the signatures. Which agency we certify me under is not high on the list of things that will make me a better, safer diver. It might not even make the list.
Different agencies break it down in different ways but in the end, there is a body of knowledge and experience that we need to gain. c-cards don't give us those things, they only serve to protect the instructor and the agency. I wouldn't consider them adequate to judge competency, at, all.
Certifications make it appear to be a set of stairs but it isn't really. It is handy to break it up into steps and we can argue about where those step should be and how many there should be but in the end an instructor and a student have a body of knowledge to convey.
I intend to build a relationship with my instructor where he teaches me in the way that makes sense. He will leap ahead and he will fall back based on what makes sense. I will dive based on what I understand and based on a reasonable progression of experience. How that aligns with agency certifications isn't as important as what he has been able to teach me and show me.
There will be certifications but they will simply be a convenient way for me to release him and whichever agency from liability and that is the reason for all the signatures. Which agency we certify me under is not high on the list of things that will make me a better, safer diver. It might not even make the list.
Is not a "rate".
You talk with them, you have discussion with them, etc. Is a useful way to understand the level of competence and knowledge of them.
I'm not tech, but I understand very well what the issues are because I usually study before saying something...
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