Triggers of Dive Accidents

[InTheDrink]

This is very much an aside:

Diver deaths are really pretty low, in very tolerable numbers. Every death is of course a tragedy for many people.

But no matter how crap or low standard current training is it serves a much more useful macro environmental point.

It is MUCH better that we get as many people in love with the underwater. That is the key point. We need to grow awareness of the underwater habitat.

I, for one, am happy to lose however many divers in the quest for appreciation of this incredible resource. There are, after all, lots of us.

My only real concern with diver training is retention. That's why I think better foundation skills help. The better your basics the more likely you will stay with this gig.

But the fundamental objective, no matter who you are, is to make people buy in to the wonder of the sea.

OOA, LOG, Equipment malfunction or no. These are all small numbers. The rape of the sea involves very large numbers. We need more people to care. It needs to be a political movement and no-one should be excluded. Not even PADI


Especially not PADI!

J

 

[spoolin01]

Can you clarify a bit (DanV)? What is the risk (no, insanely dangerous mistake) at 15-20ft requiring mitigation with >500 psi air that outweighs any benefit of the safety stop? Did you really mean to say that surfacing with 500 psi, or even ascending directly when 500 psi is hit, outweighs any consideration of a slower ascent? I thought the general understanding about off-gassing was that slower was likely to be better. If so, what is it about 500 psi that you consider so acute?

 

[MXGratefulDiver]

I, for one, am happy to lose however many divers in the quest for appreciation of this incredible resource. There are, after all, lots of us.

I'm really sorry to hear that. Personally I'm not happy to lose any divers ... particularly when the loss is completely preventable.

Wonder how you'd feel if the diver you were "happy to lose" turned out to be your spouse or child ...

... Bob (Grateful Diver)

 

[Scott L]

Can you clarify a bit (DanV)? What is the risk (no, insanely dangerous mistake) at 15-20ft requiring mitigation with >500 psi air that outweighs any benefit of the safety stop? Did you really mean to say that surfacing with 500 psi, or even ascending directly when 500 psi is hit, outweighs any consideration of a slower ascent? I thought the general understanding about off-gassing was that slower was likely to be better. If so, what is it about 500 psi that you consider so acute?

Not speaking for Dan but the possibility of a new diver not having sufficient gas to inflate their BCD upon surfacing far out-ways the benefit of a safety stop. Experienced divers? Not, as they would know to orally inflate. Dan did not indicate to accelerate the ascent but to simply to omit the optional (dive tables) SS....

 

[Ayisha]

500 psi is an immediate tell your buddy it's time to slowly ascend and safety stop. It should be taught that you are responsible for knowing how much gas you have 1st and not depend on someone else to check for you. My .02 (FYI I have 17 logged dives)

Hi there, the common saying used to be to "be back on the boat with 500 psi". Of course, we didn't really know what pressure we should start ascending at to achieve that unless we asked or figured it out. Starting your ascent at 500 psi, as you're saying above, is giving you even less reserve if you're deep enough to plan a safety stop. Starting your ascent at 500 psi would be fine on a shallow dive, but you might want to consider beginning your ascent much earlier on deeper dives in case you or your buddy have issues and need more air. You can search "rock bottom" or look at Lamont's signature to figure out how to calculate what your turn pressure and reserve should be depending on the type of dive you're doing and apply it to your own type of diving. My buddy and I usually start ascending from deep dives once the first one hits1000 psi. If we have to get back to an ascent line before that, we will usually start heading to the line at around 1300 - 1500 psi, depending on how far it is. We will then do a deep stop about half way and a slow ascent plus an extended safety stop.

You should plan to do a safety stop for deeper dives. You may want to look into the research on deep stops as well for deeper dives.

Keep reading, keep learning. Most of us probably dive differently than when we first started. I know that I've become more conservative as I go along and with all the info I read on this board and others.

 

[danvolker]

Can you clarify a bit (DanV)? What is the risk (no, insanely dangerous mistake) at 15-20ft requiring mitigation with >500 psi air that outweighs any benefit of the safety stop? Did you really mean to say that surfacing with 500 psi, or even ascending directly when 500 psi is hit, outweighs any consideration of a slower ascent? I thought the general understanding about off-gassing was that slower was likely to be better. If so, what is it about 500 psi that you consider so acute?

Assuming a depth of 50 to 60 feet--most divesites in Florida, common at resorts as well....I should have added the 50 to 60 foot depth....

If they notice they are suddenly at 500 psi, at this depth, the risk is that by the time they get their act together ( buddy team) and ascend, by the time they reach 15 feet they could easily be at 250 psi or less....I do not believe under these conditions, the new diver should do a stop. No Way!.

First, typical new diver on 50 to 60 foot dive, will probably have been down 30 minutes to 35 when this happens....even if they get to 45, this is a NO STOP required depth and duration....this means the stop is a relatively trivial issue, when compared to the REAL danger that they could run out of air at 15 feet, and then screw up in an OOA panic. If they have practiced CESA many , many times, I should think the danger would be tiny, but again, there is no need to stop in this scenario, and why risk running out of air for real?

Regards,
DanV

 

[danvolker]

Not speaking for Dan but the possibility of a new diver not having sufficient gas to inflate their BCD upon surfacing far out-ways the benefit of a safety stop. Experienced divers? Not, as they would know to orally inflate. Dan did not indicate to accelerate the ascent but to simply to omit the optional (dive tables) SS....

Thanks Scott,
And I was not suggesting a rapid or accelerating panic swim to the surface...just an immediate decision to swim up to the surface at controlled speed, inflate BC on surface, and then get to boat.

If a diver runs their tank below a safe reserve level, this means they have eliminated their safety stop unless their buddy has air enough for the both of them to hang without running out of air.

I have seen this on charter boats....new divers actually putting themselves at a real risk, for some fear of DCS crippling them if they dont get this safety stop in....
This perception needs to change....the safety stop needs to be about safety, not about adding risk.

REgards,
DanV

 

[billmosel]

I've read most of the threads on this post (most have been too repetitive) the one thing in common is to READ YOUR SPG!!! PERIOD.

If a diver is in a ooa situation (at depth), their main concern is to get air. While this should be taught, we also have to remember that a safety stop is just that.. A "SAFTEY STOP" which means that it is not necessarily a must do. Ooa (at depth) is a emergency situation and should be handled as such.

These are things that I was never taught but have learned from conversations with other divers, this forum or common sense.

The teaching agencies have to re look at how they teach what ooa really means... DEATH and how do deal with ooa.

 

[Crush]

If they notice they are suddenly at 500 psi, at this depth, the risk is that by the time they get their act together ( buddy team) and ascend, by the time they reach 15 feet they could easily be at 250 psi or less....I do not believe under these conditions, the new diver should do a stop. No Way!.

Dan, I ran into this myself at around dive 20 (perhaps less...). At 70 ft I found that I had under 400 psi (not good, I know). I am likely to endure a DIR-pile-on, but I am happy that I had an air-integrated computer and that I knew how to use it. I aborted the dive (buddy knew that I was a newb and a self-professed hoover, so pre-dive I told him that I would call my dive and ascend solo so as to allow him to finish his dive without me). Using the computer, I ascended at the maximum permissible rate (i.e., I watched the bars on the computer display) according to my computer and my training (60 ft/min below 30 ft), then switched to 30 ft/sec from 30 ft to 20 ft. I held at 20 ft and watched my computer count down both my 3-minute safety and my air pressure, both on the same display. I knew that the safety stop was voluntary, but it soon became clear to me that the (arbitrary) 3-minute safety stop would clear before my pressure hit zero. I hit the surface with 50 psi in reserve.

I can't say that all students should always try to do a safety stop. But in my case, I kept my wits about me and pulled it off (solo) without a hitch. While safety stops aren't necessary, they are good insurance. I believe that teaching students to complete as much of their safety stop as is feasible is a good precaution. A two-minute or one-minute safety is better than no safety. Also, don't forget your second safety stop (at zero feet). Hit the surface, signal that you are OK, inflate you lift bladder, and chill for a few minutes...

 

[gcbryan]

Dan, I ran into this myself at around dive 20 (perhaps less...). At 70 ft I found that I had under 400 psi (not good, I know). I am likely to endure a DIR-pile-on, but I am happy that I had an air-integrated computer and that I knew how to use it. I aborted the dive (buddy knew that I was a newb and a self-professed hoover, so pre-dive I told him that I would call my dive and ascend solo so as to allow him to finish his dive without me). Using the computer, I ascended at the maximum permissible rate (i.e., I watched the bars on the computer display) according to my computer and my training (60 ft/min below 30 ft), then switched to 30 ft/sec from 30 ft to 20 ft. I held at 20 ft and watched my computer count down both my 3-minute safety and my air pressure, both on the same display. I knew that the safety stop was voluntary, but it soon became clear to me that the (arbitrary) 3-minute safety stop would clear before my pressure hit zero. I hit the surface with 50 psi in reserve.

I can't say that all students should always try to do a safety stop. But in my case, I kept my wits about me and pulled it off (solo) without a hitch. While safety stops aren't necessary, they are good insurance. I believe that teaching students to complete as much of their safety stop as is feasible is a good precaution. A two-minute or one-minute safety is better than no safety. Also, don't forget your second safety stop (at zero feet). Hit the surface, signal that you are OK, inflate you lift bladder, and chill for a few minutes...

I think you are proving Dan's point. Ending a dive with 50 psi on the gauge is not a good idea. The gauge isn't even that accurate. Saying that you have an AI computer and know how to use it doesn't make sense when you then say you were at 70 fsw with 400 psi...the AI computer didn't do it's job apparently.