Teach me about free flow

[skinnydogdives]

why not just start with cold water regs ????????????????????????????? i know that when most people start to dine they dont spend too much on equipment but if your going to start diving in cold water (my last dive was 4 c adout 39f) please get the right equipment. my regs are the most expensive part of my kit they have been tested at 120 ft at 40f with 2 divers breathing of them as if in a panicked state and performered every time (diver mag 04 05)

 

[jbd]

why not just start with cold water regs ????????????????????????????? i know that when most people start to dine they dont spend too much on equipment but if your going to start diving in cold water (my last dive was 4 c adout 39f) please get the right equipment. my regs are the most expensive part of my kit they have been tested at 120 ft at 40f with 2 divers breathing of them as if in a panicked state and performered every time (diver mag 04 05)

Read the second sentence of the OP. Your answer is completely sidestepping his question.

 

[spectrum]

why not just start with cold water regs ????????????????????????????? i know that when most people start to dine they dont spend too much on equipment but if your going to start diving in cold water (my last dive was 4 c adout 39f) please get the right equipment. my regs are the most expensive part of my kit they have been tested at 120 ft at 40f with 2 divers breathing of them as if in a panicked state and performered every time (diver mag 04 05)

I'm happy to hear that your regulators have not let you down. However being a cold water regulator is not a guarantee, only an increased tolerance.

 

[Rainer]

Read the second sentence of the OP. Your answer is completely sidestepping his question.

Not really. He's just offering advice on how to HELP avoid the situation in the first place. If I post: "How do I avoid being eaten by the Great White after chumming the waters for six hours, then jumping in and trying to ride him", hearing that there are ways of avoiding this situation all together might serve me better in my future planning.

 

[jbd]

So, if I were in the same situation. Free flowing reg, 40 degree 100 ft deep water, my buddy next to me, what should I do.

Here is the situation the OP is asking about. At this point in the scenario, how is he to start out with a cold water regulator set???

Certainly using a cold water reg set could prevent the free flow scenario(see spectrum's post above) but this does not solve the question at hand.

All diving problems or risks could be simply avoided by not diving at all, which does not address what to do if someone does go diving and has a problem.

 

[Buoyant1]

First of all environmentally sealed regs have to be a starting point for cold water diving..that should be a must..as someone said not totally failesafe, but better odds.

If you are using a single tank, use an "H" valve configuration. Shut down the primary and breathe off of the secondary.

Using a pony, why wouldn't you switch to that and shut down your back gas immediately?

 

[Rainer]

:shakehead The only purpose the question could have is for future planning. Why not start by PLANNING to have appropriate regs? It won't solve the problem, but it'll help avoid it to a good degree. Silly to mention not diving at all. :shakehead

 

[1_T_Submariner]

I'm going to Lurk and watch more experienced answers.

My initial thought would be use all of the air possible from the free flowing reg when ascending then if around 20ish feet stop and use your buddies air for a safety stop. If it is later in the year above 20 feet you are probably in warmer water (Above Thermocline) and the chances of you buddies reg freezing are probably slimmer. If your buddies starts to free flow go to the surface.

Edit: I would like to add a question about gas planning. Do you add a specific safety margin for Temps below 40 degrees (or a specific temp)? An example might be how much more gas would you require for a 40 vs 80 degree dive to 100 feet? Redundancy?

 

[Buoyant1]

I'm going to Lurk and watch more experienced answers.

My initial thought would be use all of the air possible from the free flowing reg when ascending then if around 20ish feet stop and use your buddies air for a safety stop. If it is later in the year above 20 feet you are probably in warmer water (Above Thermocline) and the chances of you buddies reg freezing are probably slimmer. If your buddies starts to free flow go to the surface.

Only problem right now (well from what some of my friends who have been diving already have stated) it's cold top to bottom, and the thermocline is pretty much non-existant (except for maybe a few odd degrees)

I've heard my local quarry was about 41 top to close to the bottom and 38 at the very bottom.

 

[captndale]

I have been diving the Midwest for more than thirty years and have dived the deep cold water of the Great Lakes and done many under ice dives in the smaller lakes and quarries. I certainly have had my share of iced-up free-flowing regulators. As a charter captain I have seen many cases of free-flowing regulators in others.

In the initial stage, the regulator just does not quite shut off during the exhalation part of the breathing cycle. The factors that cause icing include cold water, heavy breathing and higher air density (depth). It slowly increases as ice forms in the first stage pushing on the spring and forcing the first stage valve completely open. A fully open valve can empty a full 80 CF tank in 20 to 30 seconds.

I have seen some divers advocating kinking the low pressure hose to shut down a free-flow. Although I have never tried this, if you could king the hose the hose would explode, since their burst pressure is in the range of 450 psi. I did see a hose explode once when a diver had a first stage frozen open and a second stage frozen closed. (This was not during the dive but on the surface after the dive when the diver went back to his equipment and turned the air back on.)

The real key to handling a free flow is to recognize the problem early. A free-flow, in my experience takes about two to four minutes to progress from the point where it is just noticeable to the point at which it causes a fully open valve. If a diver recognizes that a freeflow is starting early it is quite easily managed merely by terminating the dive. I have actually continued to work on a task at a 100 ft+ depth while my regulator had already begun to free-flow, knowing that I still had plenty of time to finish what I was working on and still make a normal ascent. The bottom line is that this kind of equipment problem is perfectly manageable and should not be an emergency for an experienced diver.