PSAI Narcosis Management course - 73m on air

[DevonDiver]

Tortuga.... I don't recall reading any personal attacks on you, so I don't understand why you would take people's objections personally.

I think there are a number of serious issues that rise for debate about level 6 of this course.... and I can understand totally why people are pretty hard-line in their views on the subject.

I don't remember anyone saying you were wrong to do the course. Just that the course parameters seemed excessive and that, with the trimix option available, there was just no real benefit in deep air/narcosis familiarization any more.

It's like driving your new car into a brick wall at high speed, just to prepare yourself for the unlikely event of ever having an accidental collision in the future.

I don't have any arguements against levels 1-5 of the course, except the logic that you would be accomplishing the same thing by taking any regular tech training program; where the depths attained are progressively increased to the 50m range (on air).

 

[Tortuga68]

You must be reading a different thread to me

Sorry, but I do take it personally when people say I & my friends/instructors are stupid etc, or when they make posts in my thread with the sole intention of criticising me (like saying I have bad buoancy from looking at a still photo, ***?). These guys aren't "debating" anything.

Whilst I appreciate your thoughts and input to the thread, and those of the few other people that haven been rational and didn't make up their minds before they even opened the thread, I've already done the course - so telling me it's a bad idea is a little redundant. I also know what I experienced, and that the course teaches good skills and theory. I don't think anyone else here is familiar with the course material, content etc - and I don't see anyone asking about it either.

I'm not here to justify the course or my actions. If you think going beyond PPO2 1.6 is too dangerous, then you obviously wouldn't do level 6. Some people plan dives for 1.2 or even 1.0, or limit their dives to 30m. Does that make people who dive 1.6 and 50m dangerous lunatics? No. Was I apprehensive about doing a 73m dive? Yes. But I decided that the risk was acceptable tome. And the 65m dive went sooo perfectly, every skill remembered and completed, all information and checks recorded and performed, that after that I was really looking forward to 73m.

BTW it's nothing like driving your car into a brick wall ay high speed. If you did that you would certainly injure yourself and damage your car. I sustained no injuries or damage whatsoever. So that's a terrible analogy.

 

[DevonDiver]

If you think going beyond PPO2 1.6 is too dangerous, then you obviously wouldn't do level 6.

Agreed. I think the reason so many people have been hard-line in their responses however, is that the diving industry (including tech agencies) have for a long time established a consensus about max pp02.

Some people plan dives for 1.2 or even 1.0, or limit their dives to 30m. Does that make people who dive 1.6 and 50m dangerous lunatics? No.

Everyone decides their own limitations of risk. The GUE crowd maintain a END of 30m...and for me that sounds like to expensive a proposition given the cost of helium (nice if you are on a funded cave exploration project.... but unrealistic if you are a working scuba instructor in Asia!). However, the line does have to be drawn somewhere, and - other than PSAI - everyone else draws a line at ppo2 1.6.

BTW it's nothing like driving your car into a brick wall ay high speed. If you did that you would certainly injure yourself and damage your car. I sustained no injuries or damage whatsoever. So that's a terrible analogy.

Ha ha...agreed... I am not a master of analogies!

In my mind, for the analogy, was that a deliberate car wreck was not "surely" going to injure you. It is a possibility. In the same way, conducting a dive to 73m on air also presents the increased possibility of injury.

As you say - it is personal choice on what risks you care to impose upon yourself. Everyone has the right to chose their own level of risk.

However, I would merely like to point out that the risks you took by engaging on a 73m air dive were considerably above the limits recommended by the majority of the scuba/tech fraternity, the US Navy, DAN and thethe scuba agencies (excepting PSAI).

Can you explain (I am genuinely interested) what prompted you to take the course?

On a balance of risk vs benefit... do you think the course was so valuable as to justify the chances you took?

Would you have felt happier if the instructor had used trimix, so that you had confidence in his ability to protect you?

Would you have prefered a deco schedule that didn't use 100% o2... thus leaving your essential 'safety gas' at an extremely shallow depth and virtually unaccessable until the end of the dive?

 

[Tortuga68]

Good points, soberly presented; thanks

1. Can you explain (I am genuinely interested) what prompted you to take the course?

2. On a balance of risk vs benefit... do you think the course was so valuable as to justify the chances you took?

3. Would you have felt happier if the instructor had used trimix, so that you had confidence in his ability to protect you?

4. Would you have prefered a deco schedule that didn't use 100% o2... thus leaving your essential 'safety gas' at an extremely shallow depth and virtually unaccessable until the end of the dive?

1. I wanted to do something to further the deep deco skills I learnt during Adv EAN & Deco Proc. Initially I was thinking of Extended Range (which I still intend doing). Mark suggested PSAI NM. He told me a little about it, and I agreed.

2. I'm happy with it, yes. But I don't consider it excessively risky. Obviously that's a judgement call, but if I thought there was a reasonable probability that I would get hurt, I wouldn't have done it

3. Honestly, no. I have 100% confidence in Mark's abilities. I understand your point though. But wouldn't that put them on a different deco schedule to me? It seems like a good idea to me to have the team on the same gasses and dive plan

4. No. The safety gas is not essential. We never used it. All divers carried their own stage bottles for deco. We each had at least twice as much air, EAN50 & O2 as we needed for the dive plan. The support diver at 20m and the safety bottle at 6m were just further contingencies

 

[Blackwood]

We had decompression hangs at 6m on 100% O2 lasting from 5 to 12 minutes, depending on the depth, so going to the surface would be a great way to get bent. As above, we carried our own deco gas. PSAI call it a safety bottle, go argue with the

my mistake. I thought I read the entire runtime was 10 minutes. Given that, in conjunction with your slung bottles, I understand calling it a safety bottle (or redundant deco gas).

Not trying to be too argumentitive here. My honest first impression was that you went to 74m with only an oxygen bottle hung at 6m for redundancy.

I still wouldn't do it myself, but with a more complete picture I'm less puzzled by it.

You would put 100% O2 deeper than 6m? Interesting.

if I need it, I'm bringing it with me. If it's just nice to have, I may do what you guys did and leave it at its MOD (doing that today, in fact).

As for routing the long hose under the stage, it doesn't look too terribly different than under a light canister provided you are cognizent enough to not clip the bottle over the hose (as your s drill confirmed).

 

[Mike Edmonston]

1. I wanted to do something to further the deep deco skills I learnt during Adv EAN & Deco Proc. Initially I was thinking of Extended Range (which I still intend doing). Mark suggested PSAI NM. He told me a little about it, and I agreed.

2. I'm happy with it, yes. But I don't consider it excessively risky. Obviously that's a judgement call, but if I thought there was a reasonable probability that I would get hurt, I wouldn't have done it

3. Honestly, no. I have 100% confidence in Mark's abilities. I understand your point though. But wouldn't that put them on a different deco schedule to me? It seems like a good idea to me to have the team on the same gasses and dive plan

4. No. The safety gas is not essential. We never used it. All divers carried their own stage bottles for deco. We each had at least twice as much air, EAN50 & O2 as we needed for the dive plan. The support diver at 20m and the safety bottle at 6m were just further contingencies

Tortuga,

I have a few questions / concerns about the course. They are not meant as criticism nor are they a personal insult to you or PSAI.

1. I understand that the course is designed to teach you how to deal with Narcosis at depth. But what puzzles me, is the intended use of that knowledge. Let me state an example:

You are diving with a team to 220'. There is another team that went down before you (common on liveaboards, 1 up 1 down). There is a major SNAFU at the bottom and you have to grab the nearest tank (happens to be air) so that you can help out a diver in distress (Let's assume that he's entangled heavily in a net). Everyone else is in extended Deco, and the safety diver got eaten by a seagull, therefore you're this guy's last chance.

You dive in and shoot for the bottom, knowing that it should be a quick bounce dive with a max bottom time of 2 minutes or so. You were trained to manage Narcosis and therefore feel confident that you can save this guy's life.

Here's the problem that I have, YOU WERE CHEATED!! The training you received gave you confidence, but it was under unnatural circumstances. As you descend quickly, the nitrogen levels are climbing... More quickly that your body can adjust to. At 150 to 160, the accelerated breathing rate that you are experiencing (due to the anxiety in having to save a life) hits you like a ton of bricks! Literally!! You are also retaining CO2 and starting to feel air starved. Once you finally get to the bottom, you forgot all about the BC that needed inflating so you hit the sand (or wreck). Now the narcosis really hits you, you're breathing faster, your SAC rate is approaching 2.0 and your PO2 is way above 1.6. If you remember from your Deco class, CO2 retention is a possible trigger for Ox/Tox. Now, you get tunnel vision, and ringing/echoes in your ears. You spot the diver in distress, and try to free him from the net. Unfortunately you cannot manage the coordination to disloge him as your mental capacity is shutting down.

There are only a few outcomes to this scenario:

1: The diver gets free, and now helps YOU get to the surface. You Live!
2: The diver stays entangled and Dies, and You Die!
3. The diver gets free but can't help you, You Die!
4. You Ox/Tox and You Die!

So under the best circumstances, you have a 25% chance of surviving this episode. I don't like those odds. BTW other than the seagull attack, this is an actual event. PM me if you want more details.

2. You stated that the instructors were also diving air. That to me is reckless. There is no reason to do this. If you were to learn how to manage G-Forces in a centrifuge, would you want the instructor CONTROLLING THE EVENT in a separate air conditioned room? or in the other end of the centrifuge with you at 9 G's, just hoping that his training will keep him from passing out, and therefore render him unable to help you / shut down the machine?

Again, I don't like those odds.

3. The PO2 issue. It is widely recognised that the acceptable limits for Po2 are 1.4 MAX and 1.6 as a CONTINGENCY! (20' accelerated deco on 100% O2 not included).
These limits are there for a reason, It's like a slot machine, you may have a winning streak, get a close call or 2, but THE HOUSE ALWAYS WINS! It's not IF you get a hit, but WHEN!

If they really thought out their course, they would make a "Narcosis" mix, without subjecting the divers to a possible O2 Hit. You can lower the O2% and replace it with Helium, and top off with Nitrogen so that you have a 16/5(79) mix. Goofy mix, Yes, Absolutely! Safer that Air? PO2 wise, you Betcha. Narcotic? Oh yeah, you're buzzed!

So, IMHO, the gas selection of the course is poorly designed and not well thought out. Again, this has nothing to do with you, just pointing out the reasons I think you were cheated!

4. Other than the dives, I am truly curious to know what you learned in the classroom that was not taught to you in your Tech Nitrox / Deco Procedures class? I tend to be pretty thorough when I teach those courses, but am quite willing to add data that relates to Narcosis management for my students.

Sorry my post was long winded, congratulations on your dives and remember, we do this for fun. No dive is worth your life!

Safe diving,

 

[DevonDiver]

Nice post Mike. It echos my sentiments and concerns on the course exactly.

I was never clear on the 'benefit' of this training.

I was never why this training was needed on-top of what you get in a normal extended range course.

I was never clear why the instructor concerned thought it more responsible to be on air himself.

I was never clear about the justification for exceeding ppo2 1.4 (and 1.6!) on a training course.

I can show anyone narcosis without going to these extremes..... I do it for recreational aow and deep courses. Just build a little CO2 at an otherwise safe depth.

 

[Tortuga68]

Hi Mike, thanks for sharing your thoughts

1. I understand that the course is designed to teach you how to deal with Narcosis at depth. But what puzzles me, is the intended use of that knowledge. Let me state an example:

You are diving with a team to 220'. There is another team that went down before you (common on liveaboards, 1 up 1 down). There is a major SNAFU at the bottom and you have to grab the nearest tank (happens to be air) so that you can help out a diver in distress (Let's assume that he's entangled heavily in a net). Everyone else is in extended Deco, and the safety diver got eaten by a seagull, therefore you're this guy's last chance.

You dive in and shoot for the bottom, knowing that it should be a quick bounce dive with a max bottom time of 2 minutes or so. You were trained to manage Narcosis and therefore feel confident that you can save this guy's life...

Sorry, going to have to stop you there... As I stated earlier, the course does not certify you to dive to depth, it certainly doesn't train you to rescue people from 220' or from any other depth for that matter. As I'm sure you know, the first rule of Rescue is not to put yourself at risk

2. You stated that the instructors were also diving air. That to me is reckless. There is no reason to do this. If you were to learn how to manage G-Forces in a centrifuge, would you want the instructor CONTROLLING THE EVENT in a separate air conditioned room? or in the other end of the centrifuge with you at 9 G's, just hoping that his training will keep him from passing out, and therefore render him unable to help you / shut down the machine?

I don't know why people feel the need to make analogies to illustrate points; as DD's already shown, making relevant analogies that stand up to analysis can be a difficul task. I understand that people think it's reckless, I already expressed my thoughts on it. I would be interested to hear an answer to my question about having the whole team on the same gasses/deco schedule/dive plan however.

3. The PO2 issue. It is widely recognised that the acceptable limits for Po2 are 1.4 MAX and 1.6 as a CONTINGENCY! (20' accelerated deco on 100% O2 not included).
These limits are there for a reason, It's like a slot machine, you may have a winning streak, get a close call or 2, but THE HOUSE ALWAYS WINS! It's not IF you get a hit, but WHEN!

If they really thought out their course, they would make a "Narcosis" mix, without subjecting the divers to a possible O2 Hit. You can lower the O2% and replace it with Helium, and top off with Nitrogen so that you have a 16/5(79) mix. Goofy mix, Yes, Absolutely! Safer that Air? PO2 wise, you Betcha. Narcotic? Oh yeah, you're buzzed!

So, IMHO, the gas selection of the course is poorly designed and not well thought out

I can't comment on the design of the course, other than sharing my experiences as I already have. While I accept that diving beyond 1.6 is dangerous, to the best of my knowledge noone has been injured completing this course. We all make risk assesments and make personal decisions.

As far as it being not IF you get hit but WHEN, I'm not sure how that relates to a course during which I did 16 dives, only one of which went beyond 1.6. If I was doing repetitive dives over 1.6, or planned to do so in the future, I would be more inclined to share your viewpoint

4. Other than the dives, I am truly curious to know what you learned in the classroom that was not taught to you in your Tech Nitrox / Deco Procedures class? I tend to be pretty thorough when I teach those courses, but am quite willing to add data that relates to Narcosis management for my students

Actually the PSAI course is designed so it can be done in parrallel with other deep and/or deco specialty courses, for example AOW/deep (level 1), Deco Proc (levels 2 & 3) or Extended Range (levels 4 & 5). IMHO and as I have mentioned in earlier posts, it adds techniques and information that weren't, in my experience, covered in the courses that I've done (ie AOW/deep & Deco Proc, since I am yet to do Ext Range), relating to the management of the symptoms of narcosis.

While I understand that level 6 is not going to appeal to a lot of people, and to a lesser extent level 5 and maybe even 4, I honestly think a lot of people (with appropriate intrest and training/experience/certification of course) would benefit from levels 1-3, and feel more confident of their abilities to safely plan and execute a deep and/or deco dive as a result. I know I do

HTH

 

[ucfdiver]

I would be interested to hear an answer to my question about having the whole team on the same gasses/deco schedule/dive plan however.

Not sure what's to comment on. 18/45 and Air have similar deco schedules for this dive (slightly off, 5-7min overall), but in exchange you cut the narcotic depth (almost) in half.

 

[Tortuga68]

Several people have said that the course would be better taught with the instructor/s on trimix. I'm not trimix ceritified so I'm not sure what the implications would be

I understand why people are making these comments - because they see a benefit to the instructor/s being on trimix when the student is (more) narc'd on air - but I'd like to understand it a bit better

Maybe someone could post the runtime for a student on air with EAN 50 and EAN100 deco gas, and the runtime for an instructor on trimix and whatever deco gases they would be using with trimix, for the 73m dive? Thanks

I agree that there are advantages to using trimix over air in regards to narcosis, are there any disadvantages?

I'm also interested in hearing your (ucfdiver) further thoughts on routing the primary regulator hose under the lower stage bottle clip

BTW what's the recommended MOD of 18/45?