Free Flow Incidents

[rx7diver]

Try not to be these guys:

[video=youtube;rT4E61DaytU]http://www.youtube.com/watch?v=rT4E61DaytU#t=133[/video]

Very frightening video (to me). Kudos to the diver for not panicking. But I would have assumed that one's natural tendency toward self-preservation would have urged the diver, as all his gas was being dumped, to "get outta Dodge" NOW! He demonstrated absolutely no urgency. I'm surprised by this. This is not as violent a free-flow as I've personally experienced through my Scubapro Mk 10+D400, or especially through my Poseidon Odin+Scubapro D400. Still, he was losing gas at an alarming (to me) rate!

Thanks, DaleC, for linking this video.

Safe Diving,

rx7diver

 

[DaleC]

I don't know about not panicking though. To me it appears they are either in a form of passive panic, experiencing extreme tunnel vision, or completely oblivious as to how to deal with a free flow. It looks like the person would have stood on the bottom until they went OOA.

At 1:17 the diver behind attempts to turn off the first stage then realizes the diver needs a reg donation. They signal the diver in front (who appears to be the primary buddy) but that diver does not understand or attempt to donate. Finally at 1:30 the diver behind takes control and signals to ascend.

We first see the free flow at :19 which means the diver and their primary buddy stood and did nothing for 1:10. They are fortunate the second team arrived when it did.
Wake up call!

 

[fjpatrum]

I thought he was just trying to tap the guy's shoulder and let him know there's a leak at the first stage as well. Either way, I don't understand why the guy with the freeflow is breathing off of his air2 instead of just breathing from the freeflow. He's just using up air that much faster breathing off of both. Clearly they need to do some skills practice.

 

[rhwestfall]

must have not done that specialty....

although he "aced" the silt out specialty...

 

[RVBldr]

I'm assuming he swapped to backup to trouble shoot the primary free flow. When that happens, depending on the reg exhaust, you can't see S#$% when the free-flow is in your mouth. Re: the delay..when reviewing all the threads on sizing a pony, all the consumption models seem to take into consideration 1-2 minutes at depth to figure out what's going on, so seeing this isn't surprising, however, even with a big HP tank almost full, you've got a max of about 3 minutes at 95 FFW before you're sucking air out of the tank. We've all gone through the training, but until it happens to you, I don't think free-flow emergencies get the attention they should, especially for those of us diving the colder waters.

 

[DaleC]

1-2 minutes to resolve an issue yes but when watching the video, the diver is not resolving anything (and doesn't have a pony). They watch the free flow, check pressure, half attempt to remove the neck bungee.. none of these actions resolve anything. If I saw them trying to block the mouthpiece, reach for the valve or otherwise restrict flow I might think otherwise.

Regardless, a free flow is one of the simplest failures to respond to and in rec diving should never be a cause for undue concern if one is prepared. At shallow depths and within NDL's you will have time to swim to the surface. At depth you will have a buddy to share air with while shutting down or adequate redundancy. The response is either restrict flow, shutdown and retry while on another air source, or surface.

 

[rx7diver]

I don't know about not panicking though. To me it appears they are either in a form of passive panic, experiencing extreme tunnel vision, or completely oblivious as to how to deal with a free flow. It looks like the person would have stood on the bottom until they went OOA.

Yes, and narcosis probably played a part here, too. During one of my early Great Lakes dives, an experienced diver I was with experienced a mild free-flow. He approached me and, as he told me later, pointed several times over his shoulder to his H-valve intending for me to shut down his free-flowing primary. He was wearing those big honkin' bright orange dry mitts (I think [-]Poseidon[/-] Viking made/makes them), so you couldn't miss his hand signals. Except I was sure he was simply asking the "okay" question. It was on one of my very early Great Lakes dives, and we were at recreational depth in Lake Huron in early spring, but deep. Of course, I kept responding "okay" and was getting a bit annoyed by his persistence. (Patronizing SOB!) I was completely oblivious to the bubbles all around him.

Of course, he could shut down his own valve, and he did, and all's well that ends well. Except I was the butt of some serious ribbing for the rest of that weekend.

Safe Diving,

rx7diver

 

[rhwestfall]

cost you a bunch of beers, didn't it?????

 

[rx7diver]

To the newer divers here, this is another view of a free-flow. Taken from my air-integrated computer after an actual recreational dive in Lake Huron on June 28, 1996. First graph shows depth and temp over time. Cold at the surface, and even colder at depth (colder than 39 F, as my tank was still cooling when I began my expeditious ascent). Second graph shows depth and tank pressure over time. Tank, a single HP 80 (82 cu ft at 3,500 psig), was partially spent at start of the dive and contained ~2,500 psig. Regulator was a single Poseidon Odin (1st stage) + Scubapro D400 (2nd stage).

Although my ascent was begun almost immediately when the free-flow started (with tank pressure ~1,800 psig), and although "creative" measures were taken near the end, I arrived at the surface with a virtually empty tank!

This illustrates just how quickly a free-flow through a high-performance regulator can empty a tank at depth!

Safe Diving,

rx7diver