Free Flow in the Great Lakes Region

I recently move to the Chicago area from Charlotte and am, for the first time, being confronted with the possibility of dealing with (temperature-induced) free flows. I know there are various threads on the subject, but I am curious how people think about free flow in the great lakes. I have not had a problem (yet) and have regularly dove 45 degree water in quarries and now Lake Michigan, but would like to be better educated and prepared for the possibility/eventuallity.

Do you have a rule of thumb as to below what temperature free flow is likely to occur? In the event that your gear is configured to always be prepared for this (whether it be ponies, doubles, etc.) at what temperature are you more aware of the risk?

If you have a free flow on your primary breathing source, first or second stage, is it not likely that the backup would free flow rather soon after use as well?

How much does an environmentally sealed reg (I dive an Apeks XTX50 as my primary) aid in prolonging time until free flow or avoiding entirely?

What is your plan to deal with a free flow when it happens?

Do you wait to check breathe your regs until you are submerged?

How often has this happened to folks and what were the conditions (temperature, demand on first stage, reg environmentally sealed or not)?

Thanks,

Sloan

Due to the cold water up here, I dive doubles almost exclusively. If the water's below 50 F, I always dive doubles.

A high quality, properly maintained, environmentally sealed regulator makes a huge difference. Technique also plays a large part. Three techniques I'll pay attention to include (1) adding air in short puffs to your drysuit and wing vs. hammering the inflator, (2) not inflating drysuit and wing at the same time, and (3) Inflate on an exhale. Now using doubles, especially if you also have a separate inflation bottle, mitigates these issues somewhat.

Plan if it happens? I'd signal my buddy, shut down my right post and go to my backup which is on a necklace under my chin. This is where doubles is very, very nice. I'd wait about 30 seconds, turn primary back on and see if free flow has cleared. If so, I'd continue the dive. If not, I'd end the dive.

Wait to breathe until submerged? If the air temps are cold, absolutely. If the air temps are warm, this isn't much of an issue. Also, if the water above the thermocline is warm (like this time of year), this also makes this a non-issue.

I've never had a free flow (I dive AL Legends), but I've seen it occur to students when I used to DM. Most of the folks that I'll dive with in cold water are diving doubles or have ponies and know how to handle this. However, when I DMed, when taking students on the AOW deep dive, you had to be ready to get on top of them very quickly. The tendency to want to panic is VERY REAL, which is odd since you have plenty of air. The problem is too much. But I've seen students nearly bolt from 65' just because there was uncontrolled bubbles coming out of their regs. The cold water combined with the bubbles is very disturbing for many.

Good questions!

ScubaSloan:

Do you have a rule of thumb as to below what temperature free flow is likely to occur? In the event that your gear is configured to always be prepared for this (whether it be ponies, doubles, etc.) at what temperature are you more aware of the risk?

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It is really dependent on the service of the regulator as well and the brand and design of the regulator. I dive LOTS of cold water and have only had a free flow to date on one regulator and it was a non-enviromentally sealed Aqualung Titan. This was however on an ice dive in January.

ScubaSloan:

If you have a free flow on your primary breathing source, first or second stage, is it not likely that the backup would free flow rather soon after use as well?

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It depends where the freeflow is originating from. A freeflow can start from a frozen first stage (likely both 2nds will both start freeflowing) or it can be frozen in the second stage (only 1 2nd stage will freeflow). Switching to the backup is not something that I would typically do (if on a single tank setup). Instead you should be good at breathing off the freeflowing reg and aborting your dive and ascending to the surface with your buddy close at hand.

ScubaSloan:

How much does an environmentally sealed reg (I dive an Apeks XTX50 as my primary) aid in prolonging time until free flow or avoiding entirely?

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Other than the one incident diving the Aqualung non-sealed reg, I have switched all my gear over to sealed regs. I have not had a freeflow on any of those regs. The environmental seal is important as it stops water from turning to ice inside the regulator that causing the regulator to stick "open".

ScubaSloan:

What is your plan to deal with a free flow when it happens?

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First... Make sure you have practiced breathing off a freeflowing regulator. Make sure you have a good buddy who will be with you on recreational dives. Oh, and make sure you have good service cold water regs.
Second... If level 1 was not comfortable for you, then I would recommend carrying a pony bottle of correct size. The important thing here is to train/practice with it as well so you are comfortable with it.
Third... If doing deep recreational dives or tech dives... Move to doubles so you can isolate problems.

ScubaSloan:

Do you wait to check breathe your regs until you are submerged?

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Only if the surface air temp is below 38 degrees or so.

ScubaSloan:

How often has this happened to folks and what were the conditions (temperature, demand on first stage, reg environmentally sealed or not)?.

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Only once. Ice dive in January with a warm water rated reg.

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Oh, I could add as a preventative measure.... You could move to a rebreather! Even less chance of a freeflow since the work the regulators are doing is so much less..

Just one other point: Besides all of the above, I feel that free flow is also connected on how you breath; how much gas is passing through your first and second stage. When I'm in cold water, I am conscience not to take a breath while I'm inflating my wing or my dry suit. If you place a tank in summer weather and open the valve, it won't take long and you will see frost at the port. I don't exactly know the physics behind it, but air under pressure will drop in temp when it's flowing out; thus a possible ice up if you're "hog" breathing while diving. I'm a long slow breather, and my sac rate is above average, especially for my age. I have yet to experience an accidental free flow, and I have been on regs that some would label as "vintage". I have been with divers who are almost over-breathing their regs either because they are out of shape or exerting themselves, and they tend to go into free flow much faster. What say you BoneCrusher and Divin'Hoosier about that??

Completely agree! The volume of air passing through the regulator (first and second stage) has an effect on a freeze up as well. Good point Barracuda2!

I have had a major free flow in the first stage at about 130' inside a wreck in Superior in cold water. I was too far from my buddy and had to swim very hard to get his assistance. I happened to be videotaping and I was breathing off the free flowing reg for a long time about a minute). However at that depth with a full tank you have about two minutes. I was likely seconds from an empty tank. The very serious lesson learned by me was too stick a little closer to my buddy. I also changed to sidemount and will never dive single back mount for the rest of my days. I also bought new Apeks XTX50 regs. I had a Hog sealed reg and once it was that close I just didn't trust it anymore, warranted or not it was a mental thing for me.

Stano

Man, stano, glad you made it through that experience. I dive with redundancy no matter how cold, or how shallow---peace of mind. I also dive with an H valve with a cutoff on my primary 2nd stage. Just a little added safety.

stano:

I have had a major free flow in the first stage at about 130' inside a wreck in Superior in cold water. I was too far from my buddy and had to swim very hard to get his assistance. I happened to be videotaping and I was breathing off the free flowing reg for a long time about a minute). However at that depth with a full tank you have about two minutes. I was likely seconds from an empty tank. The very serious lesson learned by me was too stick a little closer to my buddy. I also changed to sidemount and will never dive single back mount for the rest of my days. I also bought new Apeks XTX50 regs. I had a Hog sealed reg and once it was that close I just didn't trust it anymore, warranted or not it was a mental thing for me.

Stano

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Great thread with great posts from great divers!
Cold water 40º is where I have seen the majority of free flows.
Wet suits are pretty cold even with short dive times it is easy to over breath a reg if you are very cold.
Over breathing is the #1 cause I have witnessed, #2 is bumping the purge button on your second stage.
I have triggered a few while doing recovery dives under the ice but they really are manageable if you train for them.
Train for them and depending on your configuration singles / doubles etc. master your technique.

Denny if still have that green speedo I think you should do your first Grimace dive in those!
Those were very cool indeed and I think reduce drag so with blue fins you could swim faster than the paddle fish!
Come and join us at the M&G Sloan you can train with us above and below the water!

CamG

CamG:

Denny if still have that green speedo I think you should do your first Grimace dive in those!
Those were very cool indeed and I think reduce drag so with blue fins you could swim faster than the paddle fish!
Come and join us at the M&G Sloan you can train with us above and below the water! CamG

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Wearing Speedos to the Grimace??---Talk about hog breathing and shrinkage!!!! :-O

Thanks all for the responses - they have been very helpful. I need to get to a quarry to practice breathing off of a free flowing reg because *gasp* this was not part of my OW class. I actually remember seeing another glass in shallow water doing this and I thought they were just trying to make a jacuzzi because the water was cold. :classic: I also will likely get a pony, not just for free flow but because I am often diving with instabudies and am, unfortunately, not always in arms reach. Cam I can't make this meet and greet but definitely want to make the next one.