Deep diving advice that goes against conventional thought?

[jadairiii]

I just phoned a friend to apologize. He tried to tell me that some divers were gullible enough to use Trimix at 130'. I vaguely remember some people writing about it but never took them seriously.

2 weeks ago I was diving in 115' on mix, 3 of us all came back with our limit on lobsters, the other 3 divers diving the same reef came back with grand total of 1. Same reef. Wonder why......

 

[tomfcrist]

2 weeks ago I was diving in 115' on mix, 3 of us all came back with our limit on lobsters, the other 3 divers diving the same reef came back with grand total of 1. Same reef. Wonder why......

Because they didnt know what they were doing?

You are reaching pretty far here. Does mix make you a better spear fisherman too? at 115'? I bet they were super narced at that depth. PN2 of 3.4.....Man thats extreme. LOL

 

[DCBC]

For seven years, I was the Diving Operations Officer (Navy) at DCIEM. During this time, I was involved in a number of research projects that involved decompression, IGN, effects of cold water/stress on a diver, equipment operation and design, etc.

The evidence of international research is clear. IGN does affect physical and mental performance of a diver breathing air at depth and this loss of performance is often measurable in 50 FSW. Although an individual's ability is somewhat impaired at this depth, I don't believe that this is the real question to be answered. More to the point, is at what point is this impairment sufficient to reasonably cause a hazard to one's safety?

Quite often IGN is compared with alcohol intoxication. Largely this is an overly simplistic comparison and in-fact the mechanisms are not the same (The Aetology of Compressed Air Intoxication and Inert Gas Narcosis, Bennett, P.B. Postgraduate Medical Journal. Jan 1967; 43(495)68). But as DUI has been used as a comparison, let's look at this.

Most jurisdictions do not prohibit alcohol consumption and driving. They realize that some alcohol consumption (although it impairs physical and mental processes) does not necessarily equate to 'drunkenness,' or make the operation of a motor vehicle unsafe. Blood alcohol levels under 50 mg of alcohol per 100 m/l of blood, or 80mg per 100 ml (.08) are often deemed acceptable. Over these limits (dependent upon jurisdiction) a driver may be found guilty of a criminal offense.

Similarly a diver breathing Air at 50 FSW is also impaired to some degree. At this depth, the degree of impairment is considered acceptable and safe (below .08). So at what depth does a diver become impaired to such a degree that he becomes unsafe to dive? This answer is dependent upon a person's individual tolerance to the effects of IGN.

In one test at DCIEM, six Navy Divers and 14 Medical Students from the University of Toronto acted as subjects. Physical and mental evaluations were completed at the surface and at 100 FSW breathing Air. My personal performance at 100 FSW was higher (faster with fewer errors) than one student's surface results. At 100 FSW performance of physical (reflexes) and mental (problem solving) evaluations indicated better performance than all non-Navy subjects.

A second test was conducted at 200 FSW by the Navy Divers. Although the students did not participate, our performance was compared with their 100 FSW results. These results indicated that my performance at 200 FSW was equal to or better than six of the students at 100 FSW.

I don't know why this was the case. It may have been that I'd undertaken similar testing in the past (experience), that I had been taught how to 'deal with' IGN (training), genetic, or perhaps some combination of each. In any case, on that particular day my performance at 200 FSW indicated that I was not sufficiently impaired to be deemed medically unfit to dive by the Diving Medical Officer (a Hyperbaric Physician).

Regardless of depth, mixture or equipment used, self-evaluation is a crucial part of conducting a safe dive. I have no hesitance in thumbing a dive. The mixture you use is only one consideration in the planning process. The application of reason, sound judgment and good sense are mandatory but are a matter of individual perception.

I know that I'm safe to dive within my safety envelope through countless medical evaluations of my performance at depth, not because of self-evaluation or opinion. After thousands of hours I know enough to thumb a dive at a certain point. I'm aware of what that point that is through experience and independent confirmation through medical evaluation.

If someone tells me that I'm diving drunk and reckless when I'm on Air at 150 FSW, they have no idea what they're talking about! So PfcAJ I appreciate your opinion, but your experience in these matters is very limited and your expertise is non-existent.

 

[kr2y5]

I just phoned a friend to apologize. He tried to tell me that some divers were gullible enough to use Trimix at 130'.

I would be very sorry if someone was compelled to make a dramatic late-evening phone call with apologies based on a hypothetical discussion they witnessed on ScubaBoard, and without evidence that someone actually did the dive in question... speaking of gullible... .

Some posters seem to equate explaining the question with promoting it.

I couldn't agree more... I always greatly appreciate it when someone politely states their opinion and gives their reasoning behind it, the way PfcAJ just did. With this said, you now seem to be implying that there is something wrong diving Trimix below 130, which is more of a radical opinion than those stated earlier in this thread. Could you please elaborate on this, for the benefit of less experienced divers?

 

[LiteHedded]

is suppose I shouldn't tell anyone what mix i breathe regularly on 85~ average depth cave dives

 

[danvolker]

This reminds me of my ranting about Split fins versus freedive fins.... whether with fins/propulsion or with air to 180, versus Mix, we have a the equivalent of a member of one religion, telling a member of another religion that they are wrong --regardless of the miracles they have witnessed.
If there is any topic less likely to change any positions than the fins topic, it has to be the Deep Air topic/rant.

Since my dive buddies and I survived and enjoyed many hundreds of 240 to 280 foot deep air dives in the 90's, and were part of a deep diving sub-population of divers where we personally saw a wide variability in performance among other deep divers ( members of other groups we were friends with), when you went from 200 foot dives to 280....I have to say that I do see truth in DCBC's position that there are certain dive conditions that just have few challenges for certain individuals at some depths over 100 feet.

I think a Training Agency MUST come up with guidelines that are supposed to be applied to all members--and so I do endorse a GUE position that "divers should use Trimix" deeper than 100 feet....I endorse this as an agency position, but I myself , use this much like the 70 mph Speed Limit.
In my case, even though I have taken Fundies, I did not learn scuba from GUE, or deep diving from them.....I had thousands of deep dives long before they existed. I am always fascinated to read new ideas put out by them, and while I know we need a "speed limit" , I will make my decisions on air or mix based on "MY" thousands of deep dives, not on any agency position. What I do...and what DCBC does--and what we have done in the past, is probably as close to COMPLETELY IRRELEVANT as it is possible to get, for 99% of the divers reading this thread.

I think decades ago , prior to a body of knowledge existing on "THE TAO OF TECH DIVING....THE WAY OF TECH DIVING" ....some of us learned what we could reliably do, in any environment, at given depths ( in my case up to 300 feet deep..I can't speak for DCBC who I am sure went much deeper). After more dives at these depths than most of today's instructors will ever have, I don't have any plan to "un-learn" what I "learned" about how to accomplish a deep dive.

On one hand, we keep learning, and from this, I do know that I can be sharper on trimix at 145 than is possible on air.
But for an easy dive, with very good dive buddies, I have knowledge that this 145 foot air dive will be easier for me, than will a 60 foot deep air dive, for a typical OW diver. I know what an easy dive is...and I know what a challenging dive is. Again, we did thousands of these.

My point....is that I think PfcAJ is RIGHT for the general issue...that goiung forward, with the massive population now interested in tech diving, and taking instruction in it....that rules need to be there for them, and this includes SAFE LIMITS for most of them--which equates to all of them for an agency rule.

And I think DCBC and Tom are right, that people that survived the old way of learning, and did a massive number of these dives deep on air, will not suddenly be at risk if they decide NOT to follow the new Agency guidelines.

And I do believe if DCBC or Tom wanted to do a cave penetration in the ocean at 140 feet, into a new system we just found, they would probably be inclined to use Mix. But this is not the same expectation of challenge you get when considering an alternative dive to 140 off of Grand Cayman, in 200 foot vis.

 

[tomfcrist]

This reminds me of my ranting about Split fins versus freedive fins.... whether with fins/propulsion or with air to 180, versus Mix, we have a the equivalent of a member of one religion, telling a member of another religion that they are wrong --regardless of the miracles they have witnessed.
If there is any topic less likely to change any positions than the fins topic, it has to be the Deep Air topic/rant.

Since my dive buddies and I survived and enjoyed many hundreds of 240 to 280 foot deep air dives in the 90's, and were part of a deep diving sub-population of divers where we personally saw a wide variability in performance among other deep divers ( members of other groups we were friends with), when you went from 200 foot dives to 280....I have to say that I do see truth in DCBC's position that there are certain dive conditions that just have few challenges for certain individuals at some depths over 100 feet.

I think a Training Agency MUST come up with guidelines that are supposed to be applied to all members--and so I do endorse a GUE position that "divers should use Trimix" deeper than 100 feet....I endorse this as an agency position, but I myself , use this much like the 70 mph Speed Limit.
In my case, even though I have taken Fundies, I did not learn scuba from GUE, or deep diving from them.....I had thousands of deep dives long before they existed. I am always fascinated to read new ideas put out by them, and while I know we need a "speed limit" , I will make my decisions on air or mix based on "MY" thousands of deep dives, not on any agency position. What I do...and what DCBC does--and what we have done in the past, is probably as close to COMPLETELY IRRELEVANT as it is possible to get, for 99% of the divers reading this thread.

I think decades ago , prior to a body of knowledge existing on "THE TAO OF TECH DIVING....THE WAY OF TECH DIVING" ....some of us learned what we could reliably do, in any environment, at given depths ( in my case up to 300 feet deep..I can't speak for DCBC who I am sure went much deeper). After more dives at these depths than most of today's instructors will ever have, I don't have any plan to "un-learn" what I "learned" about how to accomplish a deep dive.

On one hand, we keep learning, and from this, I do know that I can be sharper on trimix at 145 than is possible on air.
But for an easy dive, with very good dive buddies, I have knowledge that this 145 foot air dive will be easier for me, than will a 60 foot deep air dive, for a typical OW diver. I know what an easy dive is...and I know what a challenging dive is. Again, we did thousands of these.

My point....is that I think PfcAJ is RIGHT for the general issue...that goiung forward, with the massive population now interested in tech diving, and taking instruction in it....that rules need to be there for them, and this includes SAFE LIMITS for most of them--which equates to all of them for an agency rule.

And I think DCBC and Tom are right, that people that survived the old way of learning, and did a massive number of these dives deep on air, will not suddenly be at risk if they decide NOT to follow the new Agency guidelines.

And I do believe if DCBC or Tom wanted to do a cave penetration in the ocean at 140 feet, into a new system we just found, they would probably be inclined to use Mix. But this is not the same expectation of challenge you get when considering an alternative dive to 140 off of Grand Cayman, in 200 foot vis.

Dan that was the most honest and unbiased comment I have ever seen from you.

 

[jadairiii]

.....
If someone tells me that I'm diving drunk and reckless when I'm on Air at 150 FSW, they have no idea what they're talking about! So PfcAJ I appreciate your opinion, but your experience in these matters is very limited and your expertise is non-existent.

Physics tells us that when we increase the partial pressure of N2 there will be in increase of impairment. You can’t get around that. What level of impairment varies but there is impairment. Oxygen and CO2 at depth also can affect the level of impairment. None of us are capable of operating outside the laws of physics, super heroes are just in the movies.

Now, as a criminal defense attorney I have represented 100s of individuals for DUIs and watched 100’s of dash-cam/BAT videos of those people accused of DUI. I have seen clients with a .08 BAL totally fail roadside tests and other with .29 and above actually do pretty good on those tests. But those that had high BAL that performed adequately on the tests are still “drunk” (as those with the low BAL's) and I would not trust any of them in any task-loading situation. The proof of that is that they were all stopped because, although they “felt” good enough to drive, they could not. Ergo, why they were stopped, they could not perform the simplest task of keeping a car on the road.

Let’s look at this from a different standpoint, going back to physics, we know there is impairment at 150, that cannot be disputed. I recently competed in a Sporting Clay tournament. At that tournament the range does not allow ANY impairment of the shooters. Personally I don’t know of any range that allows intoxicants. So ask yourself, if it is not safe to compete in a shooting tournament impaired, how is it “safe” to conduct a dive with much greater task loading at 150?

But the reality is, no one will change your mind that your not “good on air”, the real question is why are you so afraid of those of us that are trying to tell others that mix is better choice deep? Why does that bother your so? How does that affect you?

 

[DCBC]

Dan, I agree that this is a matter of perspective. If you are in a position of establishing Agency policy (as I was with CMAS Canada a few years back), there's merit in establishing depth parameters for your training programs. These are based upon the 'minimum requirements' of the program and in consideration of the likely level of experience a person will possess at that stage.

It's important to note that Agencies do not deal with absolutes. All they can do is issue maximum depth recommendations. This is especially true when there is no onus on the part of a Diver to be certified at all (in most jurisdictions).

I don't however come to this discussion representing any particular agency party-line. Each of us must choose a dive profile that they are comfortable with. I personally don't appreciate anyone telling me how to dress, what to eat, or what my safe depth limitation is (on air or mix). Especially when that individual may not actually know their own limitations and sure as hell have no idea of mine.

 

[captain]

These guys are Helldivers. Louis Rossignol (ROK) or Rock as it's stated in the article does indeed do these types of dives with regularity. Others follow his lead. They are from Louisiana. Louisiana has a culture of "Hold my Beer and Watch This". They consider themselves sportsmen, with a bit of bravado and adventure thrown in. Sometimes they die in pursuit of their sport. They would never come with me, not do I want them on my boat, as my rules and their diving style don't match. We also have a relatively serious personality clash, although I am friends with some of their members. One crews for me, but not on diving charters.

I have a fair amount of respect for them, however. We all talk about pursuing our dreams, they go out and do it. Some folks are physiologically capable of doing these dives, others (including me) are not. Many of them are not certified, because really, why bother. They aren't going to follow the rules anyway, why learn them. They aren't trying to charter, they have their own boats. They aren't buying air fills, they have their own compressors. They aren't hurting anyone else, so why not?

If we were in the Pub I'd make remarks about nanny state, freedoms to die in your own personal chosen way, and who are any of us to judge?

I concur with Wookie, I know Roc and some of the Hell Divers and have dived with some of them but not to the same extremes. It is true there have been fatalities over the years but these guys do this almost every weekend of the year and in some cases it is more than just the depth and dive profile that gets them. Some have been entangled by spearing big fish and dragged down even deeper or slammed into the rig and knocked unconscious. You could compare them to free climbers who use no safety ropes.