Deep dive / Free flow regulator

[elan]

Just to support the claim about the best cold water reg I once had my RAM's second stage slowly leaking (the reg was rebuilt, was resting on a shelf and the seat broke in letting the air leak) in 37F water in Fabruary for about 40mins. It never started a full blown free flow. If this happened on a mordern super performance regs my bet the regs would launch a free flow in less than a minute

 

[TSandM]

You have an advantage, in Monterey, in that your air temperatures are almost never going to be low enough to run a risk of starting ice if you test regs on the surface. And it's not all that often that the water temperatures drop into the low 40's, but they can. The risk of icing up depends on the type of regulator you have -- environmentally sealed regs are less likely to experience the problem.

What you do if you have a freeflow depends on where you are and how you are diving. A full-on freeflow will empty an 80 cf tank in 90 seconds (Curt Bowen did the study). You don't have much time to play around with the reg and see if you can get it to stop, but you certainly have time to get to your buddy and initiate an air-share. Be prepared for the fact that the freeflowing regulator will create a cloud of bubbles that impair vision, and will be HORRIBLY noisy. (The first time I had a freeflow, both came as a surprise, and made the experience much more stressful.) Sharing gas and immediately beginning a controlled ascent is the BEST solution to a freeflow, assuming both of you have maintained rock bottom reserves, so your buddy has enough gas to get you to the surface. If you aren't sure what rock bottom is, read the gas management article at nwgratefuldiver.com.

There is significant controversy on how to handle the freeflowing tank. If you have a solid buddy and you have practiced air-sharing ascents to the point where you can do them smoothly, then I think it helps a great deal to turn off the freeflowing tank valve. It removes the impediment to vision and gets rid of the noise, and lets everybody relax. However, that means that, if you lose the donated regulator, you are without a source of breathing gas, unless you have arranged your equipment so that you can reach back and turn your tank on yourself, and most people don't ever even try to do that. If you allow the tank to continue to empty, you may get a breath or two on the way up, even if you lose the donated reg, but you will end up with an empty tank at best, and water in your tank/regulator at worst.

 

[daz88]

Chuck,
Just an added note to what everybody else has said.....the water temp in Monterey doesn't really change throughout the year. the outside temp changes, but the water pretty mch stays the same all year round. If you're really worried about a reg free-flowing becuase of icing up, just get one rated for the temps you will be diving.

 

[ianr33]

Correct me if I'm wrong, but I don't think there would be time to safely ascend from 130' breathing from a free flowing regulator if you had already consumed a significant amount of gas.

With a full on freeflow a FULL Al 80 will empty in under 2 minutes. (Search around to find some teste done by Curt Bowen) So you are correct, you would not have enough gas to make it to the surface at anything like a normal rate of ascent.

Also bear in mind you and your buddy will most likely be doing a free ascent ,with no visual reference, in the dark. Bad time to find your Buddy's buoyancy sucks, as he either rockets to the surface, or overcompensates and sinks back into the depths with your gas supply!

Our local lake is probably similar to Monterray at depth (cold,dark) You won't find me at 130 with a single tank.

 

[tdtaylor]

DA Aquamaster has it right- carefully read what he wrote. Another way to test it out. Open a tank valve on the surface and let it run for 10 seconds- it really cools down. Do it for longer, and frost will form on the valve. Why short bursts are better than one long, short burst.

I was diving on a 95 degree day in a quarry north of us, and at 90 feet, 41 degrees, low viz and torches needed, my buddy's reg froze. With torches, low viz, it is like a white Christmas. Fortunately, cool heads prevailed, I immediately got him the reg off my pony, and all ended well (at least until 15 seconds later when he decided to bolt to the surface, but that is another story). On deep cold dives, I always carry my pony. If we had both been breathing off my main tanks primary, in a very stressful, high air demand situation, with a high flow through the primary from both of us breathing, there is a good chance it would likewise freeze.

With that said, because of where I dive, I do have regulators that are oriented to cold water diving that have never failed me. Understanding the dynamics of cold water diving goes a long way to wards prevention.

Needless to say, I haven't had these concerns during deep tropical dives at 82 degrees

 

[FinnMom]

It always seemed to me that if you are going to be spending much of your dive at 28-30m or more, a single tank is an unreasonably short dive. Doubles are really nice to balance & they hug your back in a completely different way than a single tank, even a single noticably smaller than the total volume of your doubles. The redundancy is just a bonus, and it's great for your concern.
Oh yeah, cold water also means your will probably have more thermal protection and more bouyancy. The extra weight you need to carry is much nicer on your back than on your waist.

 

[fnfalman]

I hope to get input on the risks and response to a free flow regulator during recreational deep dives.

As I expand my dive skills/knowledge, I've heard of free flow regulator dangers during deep and/or cold dives. I'm curious how significant a risk that is and what triggers it. What depths/temperatures cause those problems? The deepest I'd ever go is 130 feet and the coldest place would likely be Monterrey California. I'm not sure what the temperature is combining possible extremes of 130', in the winter, in Monterrey. If anyone knows, that would be helpful.

What is the appropriate response(s) to a free flow regulator for a recreational diver at depth? I want to take the PADI deep diver specialty but after searching here, it appears that class provides mostly deep diving experience rather than answer this question.

The reason I ask is as I expand my knowledge of recreational limits, I want to learn the most likely risks/dangers and their appropriate responses. This is not something I've heard discussed in PADI training other than breathing from a free flow regulator. Correct me if I'm wrong, but I don't think there would be time to safely ascend from 130' breathing from a free flowing regulator if you had already consumed a significant amount of gas.

I don't think that you will have to worry about free flowing regulator in California water. At least not from the cold anyway. It's simply not cold enough, not even at 130-ft.

They may freeflow from something else like an ill-maintained regular whose parts decide to give up the ghost, or sand caught in second stage.

If you're on a single tank and your buddy isn't going to be able to help much, then you better go to the surface as fast as you can without killing yourself. At that point, I think that I'd risk the bend instead of drowning.

 

[DaleC]

I've linked to this video before but I'm a shameless self promoter so what the heck.

[video=youtube;BKKpuHxGENY]http://www.youtube.com/watch?v=BKKpuHxGENY&list=UU5zvhnU0XYpf_cadpYJYkhQ& index=5&feature=plcp[/video]

This free flow occurred in Pavillion Lake with a water temp below the thermocline of 46F. Because I was diving a reserve air source, in this case sidemount, it was not much of an event - in fact I decided to video it because this topic comes up so often and swapped my GoPro on a stick to my left hand so I could do the reg swap and tank shutdown with my right. A couple of minutes later I switched back to the right tank.
The video shows that one can breath with a free flowing reg in ones mouth and that, if you have the right resources, there's no need to panic or bolt for the surface. There is also no need to have ones safety dependent upon the proximity and reactions of someone else. That's nutty stuff.

I believe strongly in appropriately sized alternate air sources.