Extreme cold water diving.

[maddghost]

WE had a dive one week ago in 34*F water and all five regs we had along with free-flowed , but I noticed that the short hose i had on froze up faster than the the exact same reg i had my long hose attached to, could that be a co-incidence?, because yesterday was our second dive after one week, and having lowered my IP to 128 i had only one slight but manageable free flow after 45 minutes on our way back to the entry point. The dive was 57 minutes max temp 37F min temp 34F about 1 knot of current from zero to max depth 60ft.

 

[grf88]

I would think it possible that the long hose could provide some heat exchange with the water although this would only impact a 2nd stage freeze-up.

 

[maddghost]

It is pretty hard to tell which of the regs are freezing up, but it's almost always the first stage that feezes up letting too much pressure build up in the hose and finally cracks open the second stage. Regardless, next week-end I will attatch another 7" hose to me left sidemount regulator.

 

[Subcooled]

Did you have one or two first stages?

Typically, moist exhaled air freezes and causes ice crystals to form in all the wrong places Hence, the second stage starts to leak. Shut the tank, switch to the alternate system, and let the reg melt...

If it is the first stage that fails then
- get a better compressor
- pour the water out of your tank
- dry the 1st stage

Your backup reg (short hose) could be less stiff.

 

[lowviz]

It is pretty hard to tell which of the regs are freezing up, but it's almost always the first stage that feezes up ...//...

How did you determine that it is the first stage?

https://divelab.com/download/proced...ubaRegulatorFreezing-ChillingFacts-4-9-14.pdf

 

[shoredivr]

How did you determine that it is the first stage?

https://divelab.com/download/proced...ubaRegulatorFreezing-ChillingFacts-4-9-14.pdf

Which page is the answer on?

 

[АлександрД]

Yes, long hose takes more heat from water, than short.
I sight somewhere special heat exchanger (was try to find it, but fail to find manufacturer). that connecting between 1st and 2nd stages, that looks like fat barrel.

In my opinion - it not so efficient, as just 1-2 feet of metal pipe, just connected in to cutted hose.
but it should be much more efficient than

also you can take hookah hose
Brownie's 50 ft.hookah hose No Tank,No Regulator, & Free Regulator Hose | eBay

Just 50 feet and attach it to the back or turn out your tank it is joke


One our guy use selfmade cut-off valve for 2nd stages:

it is the same as

but more comfortable and cheap
When one regulator goes to freeflow, he`s cut it off, and use another. Meantime first takes heat from water.

Some common rules for that -
- use dry air in tanks
- decrease intermediate pressure (7.5-8.5)

I use contraflow 2nd stages, it works fine in any temperatures. (but require overpressure valve on 1st stage).

BTW: this year some our divers sit 6 hours under the ice
Казанский репортер: 6 часов подо льдом: казанские дайверы победили время на Изумрудном озере

 

[rhwestfall]

or use one of these:

 

[Diver0001]

WE had a dive one week ago in 34*F water and all five regs we had along with free-flowed , but I noticed that the short hose i had on froze up faster than the the exact same reg i had my long hose attached to, could that be a co-incidence?, because yesterday was our second dive after one week, and having lowered my IP to 128 i had only one slight but manageable free flow after 45 minutes on our way back to the entry point. The dive was 57 minutes max temp 37F min temp 34F about 1 knot of current from zero to max depth 60ft.

I think it was coincidence. I dive every year frequently in water at about 2C, sometimes with a technical set with a long hose and a stage with a short hose and I can discern zero difference in the risk of free flow because of hose length.

The worst free flows I've seen have been while ice diving. We did some diving with air temperatures of about -15C + force 3 wind and water temperatures at 0-2C in fresh water.

Every regulator we "tested" before submerging froze until we added teh procedure to assemble the gear indoors and transport it to the dive site already assembled. Every inflator we tested or used under water (BCD's and dry suits) froze until we added to the procedure to lay submerged in the water for 10 minutes before venturing away from the entry point so the gear could warm up.

At 2C the water was MUCH warmer than the air so giving the gear time to warm up needed to be done in the water. Finally, every regulator that was activated while wet after the dive in -15C air temperatures froze.

What we took away from that is (a) assemble your gear in a warmed environment, if it is a tent or indoors before the dive (b) spend time before submerging in shallow water near the surface to allow the gear to "warm up" before leaving the safety of the exit. and (c) do not activate inflators or 2nd stages by entry or exit to the water. You must first exhale into your 2nd stage, for example, before inhaling.

Personally I don't change the IP of my first stage when it's cold because I have never seen any evidence to suggest that it helps. What I *DO* do, however, aside from the above, is that I bought environmentally sealed diaphragm type 1 stages from one of the few regulator designs that are certified and known for good performance in very cold water..... Aqualung, Apeks are the regs I use for very cold water, and I put heat sinks on the LP hose. Piston regulators are simply not good enough for these conditions with water inside the 1st stage. Don't even try that.

R..

 

[АлександрД]

Not agree with you.
Do you know Sherwood?
It has very nice dry camera - bubbles style
Sherwood Blizzard Scuba Regulator
and this is pistone regulator.

Most important for ice diving - never breath from regulator on surface.
You should start to breath just UNDER water.
And do not put 2nd stage in to the water BEFORE dive (it should be dry before)