Shallow- and Deep-Water Blackouts

[FPDocMatt]

.9% of blackouts are deeper than this, and are this is only seen in high level competitive freedivers who are diving super deep. In these cases we have advanced safety to deal with this.

What is the advanced safety?

In 2009 there were 90 fatalities from freediving combined with spearfishing in the United States. All of them were untrained freedivers. In almost everyone of these cases these three rules were not followed.

Now that's encouraging. So, if you are properly trained, and you follow the rules of safe free diving, you probably won't die.

I've had a regulator malfunction at 100ft before. Because I had a tight safety system in place, it was a non issue. I used my buddy's octo, ascended did a safety stop no big deal. If my buddy was 80 feet away from me that would have ended differently.

Man, that really goes to show, buddies should stay close together.

Here is my current course scheudle, I have 2-3 classes a month here in Fort Lauderdale. Free Diving Classes, Upcoming Free Diving Course Schedule

Thank-you for the excellent information about free diving!

 

[Griffo]

On the original question, i found that the diagram on this wikipedia page made far more sense to me than trying to understand the mechanics of shallow water blackout simply by reading the descriptions.

Shallow water blackout - Wikipedia, the free encyclopedia

 

[dumpsterDiver]

Yes taking a course does not stop accidents, taking a course and following the procedures 100% of the time on every dive does.

Just like taking a scuba course and deciding not to follow the safety procedures taught is clearly unsafe.

It doesn't matter than I can freedive to 200+ ft, have extensive knowledge of freediving safety procedures and thorough experience with freediving rescue techniques. If I wear to have a BO and be by myself I'd be toast. Just like having a regulator malfunction, while diving on wreck at 130 feet, with no buddy and no pony bottle would not turn out well.

Its funny, I occasionally freedive with my girlfriend. She is mostly a scuba diver but has taken the entry level class and can provide me adequate safety when I'm free diving in the 30-60ft range. When she gets tired and wants to get back on the boat my freediving is done. I try to bribe and/or beg her for 15 more minutes because I know once she gets back on the boat I'm done freediving.

Freediving is an amazing sport which unfortunately viewed as crazy and extreme by many. This is because most people's exposure to freediving is competition freediving.

You can scuba dive to 200+ feet, to do so requires tons of training, classes, gear, time, dedication etc.
You can freedive to 200+ feet, to do so requires tons of training, classes, gear, dedication etc.

Most people that scuba dive, are shallow reef divers that just want to enjoy being underwater.
Most people that freedives are shallow reef divers that just want to enjoy being underwater.

Dive safe!

That is interesting to hear you say that you would be unable to ascend (solo) safely from recreational depth scuba diving with a regulator failure, yet you can freedive past 200.

If you stick around SB long enough, you will soon "learn" that free ascents with scuba gear are no big deal, as long as it happens from no more than twice your breath hold depth...

 

[feitr]

What is the advanced safety?


!

Go watch some of the free diving record attempts at blue hole on youtube. Depends but often something in the order of a couple of scuba divers, 2-4 free divers (who will descend down to meet the diver roughly halfway up their ascent and accompany them all the way to the top to be ready to grab them if they BO), O2, medics, etc. with everybody being very well trained.

 

[ImmersionFreediving]

Matt,

The answer to your questions about the advanced safety is quite in involved but I will try to answer briefly. I will be traveling to Cayman for the annual PFI competition in May and they have the best safety system I've ever seen. All of this advanced safety is because the competitors are diving so deep. This is not what typical free divers do, and is not the kind of safety procedures required for typical free diving.

We will have freedivers diving to the 260-280ft range during this upcoming competition.

The backbone of the safety system is the safety freedivers. Because we know most of the issues happen at the surface or near the surface, the safety freedivers are our main line of defense. The safety freedivers will be covering the top 1/3 of the dive. For example on a 150ft dive, safety freediver would be following the athlete up from 50ft to the surface. If there was an underwater blackout there would be someone right there to instantly close the airway bring them to the surface. Once on the surface with proper rescue techniques they would back and breathing in 3-5 seconds.

That covers 99% of what would ever happen, and only rarely ever has anything other this ever been required. But lets take worse case scenario, what if the athlete had a blackout at maximum depth, which by the way has never happened, but hey what if they had a heart attack or something. In this case there are safety tech divers at depth. They have a special attachment that attaches a lift bag to the divers wrist and shoots the athlete up the line. If the safety freedviers waiting at 1/3 the depth have been down too long they go up to the surface and a second safety of safety freedivers go down to replace them. Either way there are safety freedivers waiting for the athlete to swim up on their own or be shot up the line via the lift bag. Once they get to the safety freedivers the safeties would bring them up the surface.

What if the scuba diving safety, and the safety freedivers all got eaten by sharks, and the athlete had a heart attack while at depth. If the athlete is not seen in a pre detmermined time, a counter balance is tripped and this brings up the whole line, and the diver as well. The diver is attached to the line by a lanyard. So if the counter balance is tripped the diver is coming up one way or the other.

Please understand I'm over simplifying all this but the safety system in this particular competition I'm going to is the best I've ever seen.



Also while I can freedive to 200ft, I would prefer not to do a free ascent on scuba from a 130ft because I can't do a safety stop and I would certainly be ascending faster than recommended!

 

[FPDocMatt]

On the original question, i found that the diagram on this wikipedia page made far more sense to me than trying to understand the mechanics of shallow water blackout simply by reading the descriptions.

Shallow water blackout - Wikipedia, the free encyclopedia

Wow, this diagram shows quite clearly that hypercapnia is your friend. When you get the strong urge to breathe, that's the time to surface.

I presume that holding one's breath for longer and longer periods is not so much learning how to ignore the urge to breathe, but by extending the time before you become hypercapneic and/or hypoxic...?

 

[beaverdivers]

Thanks Ted for the Up-to-Date Info.

I'm glad to see Free Diving is Alive and Thriving!

 

[Thalassamania]

...

Also while I can freedive to 200ft, I would prefer not to do a free ascent on scuba from a 130ft because I can't do a safety stop and I would certainly be ascending faster than recommended!

Free ascents at 60 FPM are not that difficult, In the old days we had to do them from each depth bracket (30, 60, 100, 130, 150, 190), safety stops are just that safety stops ... no required.

Wow, this diagram shows quite clearly that hypercapnia is your friend. When you get the strong urge to breathe, that's the time to surface.

I presume that holding one's breath for longer and longer periods is not so much learning how to ignore the urge to breathe, but by extending the time before you become hypercapneic and/or hypoxic...?

Yeah, you sort of "burn out" your CO2 sensors.

 

[ImmersionFreediving]

Wow that's some serious training!

 

[Thalassamania]

That was standard in science diving from the 1950s up until the 1980s when the free ascent requirements were reduced. The last time I had to do a depth qual free ascent was in the early 1990s, that went from 190 up to 20.