Pony as regular equipment for all dives?

[shoredivr]

OK I should have expanded my post a little - a diver with a pony is equipped as a solo diver. Without knowing any more about them (i.e. I just met the guy on the boat) I am going to assume they are a solo diver, because I am also someone that can and does dive solo. I don't want to dive with this person because I don't want to return to the surface half way through my enjoyable dive when they have lost contact with me. I will make my dive on my own (assuming no one else is available and I am using doubles) and let the "solo" diver dive on their own too.

Missing from this assumption, that divers with a slung redundant tank are solo divers who just drift Inattentively away on you, is location: the concept of cold water diving.

In cold water diving free-flows are not uncommon. Many Great Lakes non-doubles, non-sidemount recreational divers have redundant smaller slung tanks. It's a safety issue.

They may be good buddies or they may not be, but a slung redundant tank is no indication of this. In fact I'd rather dive in cold water with someone, including an instabuddy, who has a redundant tank than not.

And I've dived with plenty of instabuddies who just drift away, too. A person can be a solo diver and also an attentive buddy when they are not solo diving, it's not mutually exclusive.

 

[chrisch]

...
In cold water diving free-flows are not uncommon. ...

I have seen this written a large number of times and want to explore it. Firstly let us agree what is "cold". I dive UK sea and French caves. The latter I would suggest as "cold" with ambient of about 6-8C. I have also dived the Italian lakes a fair bit down to 4C. So my diving is to 4C (40F).

There are parts of the world that are colder for sure. That is outside my experience.

I read that cold (whatever that is) water can freeze regulators. I used to ice dive the lake a few years ago and being in an overhead environment I would agree that the combination of cold water and overhead it is a good idea to have a backup.

In some 30 years diving I have never had a freeflow. I have never had a buddy have a freeflow. I guess I must be at 2,500-3,000 dives now. As a guess. I stopped logging them 20 plus years ago. Maybe 10% of these in "cold" (sub 10C).

So my personal experience (not seeking to challenge or query that of others) is that a freeflow is very uncommon in water that I would describe as "cold" (sub 10C). In fact not just uncommon, but rare to the point of being non existent. So clearly I am missing something. Either the definition of cold or the absence of badly tuned, poorly serviced equipment. Nevertheless I go with the crowd - I take my bailout ice diving with me. I even tell other people they should have one. (Mainly as it is an overhead environment)

But - in all honesty - I wonder if freeflows are genuinely "common" anywhere and if they are whether they are just a bad choice of reg for the conditions or badly maintained equipment?

 

[shoredivr]

Dorset is not quite the same as The Great Lakes weather wise, mate. In the winter here water temp is as low as 33F - 34F. Then it freezes most years.

In the summer below the thermocline it's 40F - 42F.

First charter boat of the season in May in Tobermory you are looking at 39F.

I have seen well maintained regs freeze while ice diving. Nice slushy ice crystals in the mouthpiece.

I have seen well maintained regs free flow at 130ft at 39F.

Probably seen ten free flows happen to buddies. Had one almost free flow myself while ice diving. A well maintained cold water reg too,
I may add.

It's not only the cold water that makes the problem. When the air temperature being below freezing means that the equipment is already cold. Experienced divers up here do not breathe from a regulator above the water when it is warmer than the air, rather you put the reg in your mouth under water. That way you reduce the risk of reg freeze.

A diver somewhat over breathing a reg while at the same time hitting the inflator on a wing/BCD or drysuit can also set up the conditions, had a buddy do that once. So I took notice of these things when diving Great Lakes cold water and avoided inflating wing or drysuit while inhaling using a single tank set up. Then I got a redundant tank, and now I dive sidemount mostly.

A secondary problem in very cold water is drysuit inflator freeze up. A number of years ago an accomplished local tech diver died when his wing inflator froze open, he was unable to detach the inflator, and went from 80 ft to striking the undersurface of the ice in an uncontrolled ascent.

I dive what makes sense to me given the conditions, and I speak from my experience over a decade of winter diving.

 

[chrisch]

...
I have seen well maintained regs free flow at 130ft at 39F....

As I said the majority of my cold water diving is in continental Europe including cave diving. 39F is 4C and this is not an unusual temperature as far as I am aware.

Again I would like to explore the issue without wanting to get into an argument if possible. Let me share my view with you and I hope your experiences can shed some more light on the matter.

Firstly, it is my opinion that a regulator free flow is a fault and should never happen. I do not accept that a "well maintained" regulator should fail and certainly not ever fail at 40m. The first thought is that many people do not understand the issue very well and mistakenly buy high flow regulators. The main culprit (that I read about) is the ScubaPro Mk25. The manufacturer of this unit recommends that it is de-tuned for cold. So it is not the matter of maintenance but of correct tuning that is relevant. It is (as you well know) the expansion of the compressed gas that causes cooling. The ambient water temperature is used to "heat" the reg and prevent freezing.

I have dived with a mixture of regs over the years, my current setup is a mix of SP Mk17 and Apeks. I have used Mk11 and Mk17 for years and never had a freeze up or a free flow.

You are right that breathing on the surface is a bad idea and that air temperature is a big issue. The last time we dived lake Iseo in Italy the air temp was about -5C how does that compare with your air temperature?

Humankind is capable of travel to the moon. Are we really incapable of building a scuba regulator that can cope with diving in cold water? I think not. I think thousands of cave divers around the world would find another hobby if free flows were anything other than something we read about happening to other people on the Internet.

 

[halocline]

But - in all honesty - I wonder if freeflows are genuinely "common" anywhere and if they are whether they are just a bad choice of reg for the conditions or badly maintained equipment?

I'm not a cold water diver, but I do have a theory as to why we read about lots of freeflows in cold water. It has to do with unfortunate trends in regulator design; less metal, more venturi assist, smaller 2nd stages that offer less heat sink properties, and regs tuned to impress test machines. I guess this is to satisfy a market in which the vast majority of buyers are A) new divers primarily diving on vacation and/or in warm water and B) shops and individual buyers focusing on comparative breathing numbers (which do not present an accurate picture) and travel-worthiness.

Just a thought.

As to the topic of this thread, I do find my 13 cft pony very useful for inflating tires and soaking/leak testing regulators. I've used it on exactly one dive in the 10 years I've owned it. For me, if I dive in situations that I feel require redundancy, I use doubles. I would like to see some statistical proof that a small bailout bottle has actually saved lives, I seriously doubt that it exists. But people sure feel better using them.....

I'm sure that opinion will be less-than-popular on this thread, sorry about that!

 

[shoredivr]

You are right that breathing on the surface is a bad idea and that air temperature is a big issue. The last time we dived lake Iseo in Italy the air temp was about -5C how does that compare with your air temperature?

Humankind is capable of travel to the moon. Are we really incapable of building a scuba regulator that can cope with diving in cold water? I think not. I think thousands of cave divers around the world would find another hobby if free flows were anything other than something we read about happening to other people on the Internet.

The coldest air temp in my log book is -9C with wind chill.

I would agree with Halocline about the lack of heat sink on modern regulators being part of the cause.

I know what I've seen diving here in regards to free flows. You can believe whatever floats your boat. Have a scintillating day.

 

[drbill]

For years I always carried a pony since the vast majority of my diving is solo. Then I had surgery a few years ago and risked going it without the pony due to the added weight. I've had several surgeries since then (and another one coming up in two weeks) and haven't put the pony back on. I realize I'm taking a risk and really should get used to carrying the pony again. I don't worry about OOA issues, and my reg set-up is pretty near bullet proof (but not 100%), but...

 

[chrisch]

...
I know what I've seen diving here in regards to free flows. You can believe whatever floats your boat. ...

I like to believe whatever the data proves is the truth. Your anecdotal data is that you have seen (I note you have not had personally) a lot of freeflows. However, you have not given us any real figures or further information to go on. So I believe that a free flow is a regulator failure and something we need to prevent rather than accommodate.

Carrying a bailout in a cold water environment is great - no debate - but why will the regulator not fail on the bailout if it is of the same poor design or whatever problem it is that the primary regulator has got? I read a lot of folk recommending a "better" or "just as good" reg on the pony. For me that means the same make and spec. of reg on the bailout as on the backgas. If that is failing so commonplace as you report I would personally be very worried that my bailout would fail too. Hence my view about high performance regs being too highly tuned.

I have seen (well heard more exactly) a lot of freeflows at the surface in UK quarries. Training divers, poor kit, all sorts of reasons. But I have no hard data on it. I've never gone up and asked anyone why their regulator is malfunctioning. I guess a lot of the schools wouldn't appreciate that.

My guess is that the cracking pressure is set up too low. Rookie error for the service outfit. That and people dropping the 2nd stage into the water. None of it problematical (although in very cold water you will get 2nd stage icing). My concern is 1st stage freezing underwater. With doubles you can turn the valve off and hopefully the reg will thaw out. That's the theory anyway. I have never had any experience of it actually happening.

So I really would appreciate any more data from anyone. I'm afraid my only input is my direct experience and I have never had a freeflow.

 

[Coztick]

May I ask, what IP should I set my dst and fst for near freezing temps?
And would you leave them detuned for Carib. rec. trips?

Thanks

 

[chrisch]

May I ask, what IP should I set my dst and fst for near freezing temps?
And would you leave them detuned for Carib. rec. trips?

Thanks

I'm not a service technician but I do own a DST. I have never asked for it to be specially tuned for cold and it has never free flowed. The "problem" (from reading forums) seems to be mainly the SP Mk25. The solution to that reg (from reading forums) is a de tune. It would appear that piston regs are more an issue than diaphragm.

I bought and read the Vince Harlow regulator book and this seems to back up my hypothesis. As mentioned earlier in the thread the fashion for adjustable venturi and the ability for the diver to influence the 2nd stage might be an issue. Again I use the cheaper, non-adjustable 2nd stages and have no issues, nor have I ever felt the need (or desire) to adjust the 2nd stage before during or after a dive.

Personally I would leave your Apeks just as they are and expect no problems. Why should such a quality regulator be unable to cope with cold water?