The following blog article from John Clarke made the social media this weekend following the successful TekDive USA the previous weekend where a compressed version of the article was presented
The article describes how close the temperatures get to freezing (or never actually get above in some cases) even when the water temperatures are above freezing. It contains some very relevant information and detail for those who dive in cold waters (most UK divers!)
A recent incident reported to me showed that with a single cylinder and an uncontrolled free flow on the surface, you can empty the cylinder in 3-4 mins. Once the ice has formed, you are not going to be able to shut the free flow down unless you close the valve.
If you have a free flow, signal to your buddy to air share and then shut down the offending valve (either you if you can reach it, or your buddy if you can’t). Whilst you can breathe from the free-flowing regulator, it is a distraction and will make things more task-loaded. If you can’t shut it down, get it away from your field of view for the same reason.
Your gas planning should have covered getting you and your buddy from the max depth at any stage in the dive sharing during the ascent so you should have enough gas to share during ascent. Don’t panic, just ascend as planned in a calm manner.
I have been approached by a manufacturer about free flow incidents and whether I had any data. I said that it is likely to be considered ‘one of those things’ when cold water diving and as such is poorly reported, yet I am sure we have seen plenty over the winter months. Therefore, if you have had an uncontrolled free flow, consider reporting it to DISMS