Your reaction to this emergency situation.

[Tortuga68]

A quick question relating to the narcosis issue. I have been to a max depth of 30m (100') and did not feel that I was affected by narcosis at all. I realise I probably was and just couldn't tell, but in the case of chasing down a sinking buddy, could you expect to get a sense of "I'm getting badly narced and am about to lose the ability to make decisions" or would you just happily keep swimming to your demise?

Is it something you can feel coming, and manage? Or will you be oblivious to it by the time it's too late?

It depends on a lot of factors... but if you didn't notice it at 30m and the rescue was your first time below 30m then you might just keep going. You'll probably be breathing harder from finning to stress so you'll get some CO2 buildup as DD said, which makes the narcosis worse and can also lead to blackouts

 

[Thalassamania]

Well, not to sound too much like a tool, but because that is what NAUI taught in my cert, and to freelance and do otherwise could make me liable . . .

The ascent rate was stressed to be 30 ft/min, more to protect yourself than anything else, I believe. I tended to want to go a bit faster, and got called on it every time . . .

As far as the swimming ascent, to me, that one is simple - more control. You handle the victims BC to keep more or less neutral, and swim up. If you go positive, it's a lot easier to have the victim take off like a torpedo if you for some reason have to let go, and that ain't good . . . . Frankly, I don't think it would matter which you choose if you can control it . . . we were taught to swim up, and that's the way I normally ascend anyhow, so didn't really take any issue to that . . .

And I hear you about conservatism these days . . . I certed initially in 1979 (computer? That's a big, hot thing in a very large room . . . . divers? We have the US Navy tables . . . ) and the tables now have about half the NDL we used to use, and the 30ft/min is painful compared to what I used to be used to . . . But magically, we didn't get bent back then either . . . I think this is what you get when the certifying agency let's their legal department/risk management group write the specs . . . likely more to keep them from getting sued than the "best" solution for us . . .

But I digress . . .

- Tim

To start: NAUI did not teach you, your instructor taught you. In fact, there are few "facts" that NAUI insists on, and the exact order of things in a rescue doesn't make the list. Yes current USN ascent rates are 30 fpm, but many of did thousands of dives apiece at 60 FPM before the change, and a lot of us still do, at least to 20 feet of so. I'd establish an up with my BC and dump the victims. I'd use my BC to control our ascent. Weightbelt can go at the surface, if need be. The NDLs for the new USN tables are not significantly changed, the NAUI tables are nothing more than one step back from the USN (or a partial step, e.g., 8 @ 130 rather than 10).

 

[knowone]

DCS can be mended, dead cannot.

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No effing arm wrestling here

I Respect DevonDiver

and let no man out of my sight to be left behind

 

[DevonDiver]

Well, not to sound too much like a tool, but because that is what NAUI taught in my cert, and to freelance and do otherwise could make me liable . . .

I'm not sure about the liability issue - that must be a regional thing. However, you do realise that on the course, they won't allow you to do faster ascent rates - because it is a course and a high safety standard must be maintained? You'll be doing multiple ascents in training - and there's no wisdom to pushing ascent limits during a role-play. Training and Real-Life = not the same.

I don't let my rescue students conduct fast ascents in the training environment either. That doesn't mean I encourage them to do leisurely, ultra-conservative, ascents if someone's life was actually on the line.

The ascent rate was stressed to be 30 ft/min, more to protect yourself than anything else, I believe. I tended to want to go a bit faster, and got called on it every time . . .

Yes...in training. As I said, I wouldn't allow a faster ascent rate in a simulated emergency... because nobody is really going to die.

PADI teach 60ft per minute as a standard ascent rate. They hit 2 million certifications this year. That's a lot of divers, doing a lot of dives, over a long space of time. Basically - quite a large sample size that determines a high degree of relative safety for the ascent speed. You really think that 60ft per minute is likely to present an unreasonable risk to your own safety? For recreational dives - especially at shallow depths or for short bottom times - 60ft is still very conservative.

Yes, 30ft per minute is optimal to ensure the maximum conservatism and safety for the diver. But I hardly think that 60ft per minute presents an undue risk - especially when the situation is absolutely time critical.

EXAMPLE

From 100ft... at 30ft per minute, your ascent will take at least 3mins and 20 seconds.
+ 3:20 mins

Add to that any time stopping to "check their releases", "remove their mask" or otherwise diagnose or inspect them... plus allow for some 'panic seconds' as you have to deal with the reality shock of it.
+ 30 secs

Now..did the diver stop breathing just as you reached them? Not likely... so how long was it since they stopped breathing and/or it took you to reach them? How long did you stare at them for, wondering what they were doing before the 'alarm bells' rang? How long did it take to fin down to them and make contact? 2 minutes?
+ 2.00 mins

Now.. add to that some time at the surface.. establish their buoyancy - establish your buoyancy - raise the alarm - check their breathing - remove your mask - remove their mask...then get around to initiating rescue breaths... Another 30 secs to 1 minute?
+ 30 secs

Trust me... that's realistic. It's realistic for a no-stress training scenario - I know because I use a stop-watch to time my students doing rescues. I've seen rescue students take a lot​ longer than that. In a real situation, there's a lot of shock-stress to account for... that can slow things much further.

So.. how long does our rescue take? From observation until the first rescue breath.... about 6 minutes!

Now... a reminder:

PADI RESCUE INSTRUCTOR MANUAL - Basic Life Support for Dive Emergencies.

Time is critical because without oxygen, brain damage can occur in four to six minutes.
After six minutes, brain damage is likely and after 10 minutes it is almost certain.

Of course, I can't tell you what to do - it's your safety and your decision.. BUT... your ultra-conservative ascent is basically condemning the victim to almost certain brain damage, at the minimum. In reality, they'll probably be dead.

Be as leisurely as you want - but if so, just recognise that you're probably doing a body recovery, not a rescue.

 

[shortdivemedic]

I just hope if ever faced with a situation as above, I would make the right decisions and use good sound judgement so we could all talk about it over a beer later.


Cheers
Michael

 

[dumpsterDiver]

I didn't imply to leave them brick heavy - go for neutral. As I said to DevonDiver, I prefer neutral with a little finning to ascend - easier to keep the rate from getting out of hand that way . . . and really not much work. Also, that was our training in rescue . . .

- Tim

I tried to explain why this is not what I would do. Of course rescue training is NEVER going to teach you to do a bouyant ascent unless your own life is at stake. They are not ever going to teach you to dive past 130 feet either.....

I have experience in diving deep and chasing fish down when spearfishing. Believe me, if you sprint at 100% effort for 45 seconds (or even less) at depths below 150 on air, it IS going to kick your assss. You WILL be narced and it is hard to catch your breath at that depth or deeper. The last thing I would want to be doing is more kicking than is needed... The CO2 and narcosis can combine to incapacitate you (although I have never had that happpen).

You want to avoid exertion at depth, that is why I would stop kicking as soon as possible. It is more important to not over-exert. Once you caught the victim, inflate the BC just enough to get the party started and ride them up and dump air as needed.

People seem to think that the diver is going to blow up and float away and get in a run away ascent. This is NOT going to happen at depth. Do you have expereince diving deep (say well below 100 feet)? Look at the physics of it, the air in the BC does NOT expand very fast at depth. For me, I would be much safer resting, catching my breath and manipulating the divers BC.

So lets do the math on the air in their BC.. lets say you add 1.5 gallons of air to their BC at 132 feet and this gives you and them a positive buoyancy of 12 lbs. What will be the bouyant force of that BC when you get to 66 feet (with no dumping)?

I calculate an increase in bouyancy of only 8 lbs. This is not a huge amount. If you were comming up from deeper the expansion is even slower. Of course the wetsuits would be expanding some too, but the idea should be that the air in the BC is not going to explode and drag the victim out of your hands. The expansion of air is not super fast and is manageable.

Also, you may be better able to judge the ascent rate if you are simply holding the victm and dumping their air as needed. If you get them neutral and start kicking, you are going to have to vent air from their BC too (AND modulate your own kicking). Either way, you are going to have to keep dumping air from their BC on ascent.

It would be very easy to dump excessive air from their BC and this would be hard to detect because you are still kicking. How would you manage to keep their BC neutral on ascent while kicking? The only way to check is to stop kicking, and wait and then see if you are sinking or floating.....This is much more exertion and harder to manage than trying to modulate the release of air from the BC, so you maintain a steady and controlled "ride" to the surface.

 

[tadawson]

Be as leisurely as you want - but if so, just recognise that you're probably doing a body recovery, not a rescue.

Frankly, if you find a guy unconscious and not breathing underwater, and you didn't see him nod off, that's likely all you are doing anyway . . . sad but true. It's not this scenario, but in that case, you don't know if it's been 10 seconds or 10 minutes . . .

- Tim