Ice diving/Winter diving - freeze ups and free flows

[off the grid]

We recently had an ice dive training which had multiple freeze ups and free flows mostly related to BC valves and one full face mask. Temperatures were in the 20's (F) with a slight wind. Water temps in the mid 30s. Most of the free flows happened after divers were under for a short while so the equipment was working on entry and not already frozen. Have other teams had similar problems, and if so, have you come up with any solutions besides moving your team to Costa Rica?

We did have hot water ready to go and were able to thaw out equipment fairly quickly but you wouldn't want to be doing this during a mission continuously. Also, for a call where we might still be in rescue mode, I would prefer to dive with my normal regulator (Sherwood Blizzard) and mask rather than a FFM and risk the freeze up and the hassle of the FFM in cold weather. Any opinions on that?

Thanks,

Randy

 

[rhwestfall]

Regs need to be above the water or below the water, not both. Same with the lpi. Once it has been wet, it needs to stay in the "warm water". Put the reg in your mouth as you descend. Yeah, FFM seems like such a good idea until it gets wet and freezes in the air...

My first ice class was with air at -25F. We only had one free flow/freeze flow.

 

[rhwestfall]

I will ask too, what regs were bring used?

 

[rhwestfall]

Most of the free flows happened after divers were under for a short while so the equipment was working on entry and not already frozen.

Ice inside the regulator can exist and the regulator can function. It is the growth of the ice to a size it fails the regulator that will get you.

 

[shurite7]

It is curious as to which regs you were using. Using FFM under the ice is rather nice. I’ve never seen a FFM let go in cold water, unless it wasn’t serviced properly. It is hard to answer your question, since there isn’t a lot of background information, without sounding condescending. Be sure not to breathe the regs while on the surface or let the second stages drop into the snow. Try avoiding letting any water in the second stage before entering the water. If possible, set the equipment up and test it before departing home. It is recommended the hose protectors be removed to allow the water to flow over the hoses and first stage rather than remaining stagnant inside becoming colder as air flows through the hoses.

 

[rhwestfall]

Be sure not to breathe the regs while on the surface

And here lies the challenge of a FFM... Exhale moist air while on the surface through the regulator can lead to ice forming. The surface valve is a must, but you still need to really be cautious as to breathing the reg....

 

[shurite7]

And here lies the challenge of a FFM... Exhale moist air while on the surface through the regulator can lead to ice forming. The surface valve is a must, but you still need to really be cautious as to breathing the reg....

All one has to do is put the reg in the mouth or the FFM on with the surface valve open, then put their face into the water and breathe. If all is good, descend.

 

[Bowers]

Getting moisture in the regs is the big problem. Breathing on them before going underwater can be problematic. It’s also very important to keep breathing rates controlled. The faster you breath, the more the expanding air cools and at some point it will cool faster than the water (wich is cold but obviously above freezing) can warm things back up.

On the ffm vs blizzard note, during an emergency you may be jumping into water that has toxins such as gas, blood or sewage and a fully incapsulating suit (which includes using a ffm) is a must for your health.

 

[off the grid]

Thanks for the replies. We use Deviators but only one mask free flowed. The other free flows were from inflator valves. The first two people in the water did not have free flow problems. People later in the line up had issues and after seeing your replies I think that was for two reasons. First, their gear was out on the ice longer and at times lying on the ice which also had puddles of water from the hole. Second, there were weighting issues that required resurfacing for each of these later groups. It was on the second descent where the free flows happened. We'll concentrate on those issues next practice.

Also the points about using the FFM for protection from contaminants and just to avoid the face freeze on entry are points well made.

Thanks again for all who responded.

 

[Jim Lapenta]

Inflator valve freeze ups can be due to water in the LP line, poorly maintained inflators, and inflators that have very high flow rates. They are not all the same. The other issue is improper technique with the inflator. This is a skill/training issue that can sometimes be traced to overweighting.
I've had a few PSD divers take buoyancy and trim workshops with me just for recreational diving and it becomes clear pretty quick that overweighting is a major factor in their problems. This translates into icing inflator issues in cold water because they have to use it so much once they start to drop.
They'll have spent tens of thousands of grant dollars for sonar, custom drysuits, ice boats, etc. But rarely train and when they do, it's a reinforcement of bad basic diving habits.