A bit of a long read:
This winter at one of the local lakes I dive there was a truck with a trailer and snomobile that broke through the ice and sunk, furtunatly the driver and his dog managed to escape and walk to safety. My dive partner and I have been wanting to locate the truck and dive on it. We finally got the time to take my boat out and try to locate the truck with only a vague area of the accident. There were three of us that would be diving together, my buddy who is an instructor, me a dive master and another diver with less experience who is part of the local fire department dive team and a good diver. We spent about 2 hours with the sidescan but had no luck finding the truck on sonar.
We decided to make a dive in the area so that we could see what conditions we would be diving in if we were able to locate the truck at a different time with hopes of recovering the snomobile if we ever locate it. The bottom was about 120ffw.
The water in this lake is cold with a surface temp of 54 and drops quickly as you descend, my last deep dive in this lake was mid summer last year and the bottom temp was a balmy 37 degrees Fahrenheit. Drysuit and thick undergarments are a must as well as good cold water regs. I normally dive using my aqualung legend regs but on this dive I would be using my new OMS regs with about 5 dives on them.
We both dive similar setups oms backplate dui dry suit and pony bottles. We were near an island with a wall that drops from 15ffw to the bottom at just over 120ffw so the dive plan was to anchor the boat in shallow water then follow the wall down to the bottom check the conditions then work our way back up. The visibility was next to nothing and went black at about 30ft, nothing we haven't dove in before but we usually have better viz in this lake. My buddy was in the lead with the newer diver in the middle and me bringing up the rear we had to stay close due to near zero viz. Everything was going good on the descent and the lead diver stopped to check we were all good to keep going at about 75ffw. At 94ffw and still descending I got a blast of bubbles around my neck and face, damn a free flow, water temp was 43 degrees. I immediately started checking to see where it was coming from and went to a feet down position in case it was my drysuit valve I didn't want it going to my feet. Because it was around my neck my first thought was that my drysuit valve had malfunctioned and I was venting through the neck seal, I opened my shoulder dump all the way and unplugged my drysuit. That didn't stop it. I knew I'd have to abort the dive regardless and knowing that my dive partner had another diver with him I decided not to chase them down but to surface on my own. It took a few seconds to figure out it was coming from my alternate I wear on a necklace around my neck I even took my primary out to make sure it wasn't coming from there. The alternate is the last place I expected a free flow because that's always in predive and detuned with the control knob to be tight to breath through to keep it from free flowing on the surface. The water was black so I kept an eye on my computer so I didn't surface too fast and kept checking my spg to make sure I still had air. My primary was still breathing just fine and I had my pony ready to go just in case I needed it. I made a two minute stop all the while messing with my secondary to try and get it to stop blasting my air out, it didn't stop free flowing until I had been on the surface for at least a minute tank pressure was about 300psi
Luckily it happened on the initial descent and I had a full 100 to start with. Like good divers my buddies were on the surface about 4 minutes later after they made a 3 minute stop.
I have gone over the scenario several times and had a discussion with my dive buddy and I don't think I would have done anything different. In clearer water I could have signaled a problem but due to the black water and knowing I wasn't leaving him alone I decided to abort alone knowing I had redundant gear.
A few takeaways, I have been on a few dives where things have happened and have acted accordingly but was happy with myself when I had an emergency happen to me. I kept cool knowing I had an extra air source if mine completely failed.
OMS had issues and recalled all their regs due to free flow problems a few years back but this was the new and improved regs. You'll never catch me with oms regs in my mouth again, I do love their other gear though.
A pony bottle is a must for me now on deeper dives and I'll always have it by my side, never thought I would need it but certainly glad I had it.
I'm sure there will be divers armchair the heck out of this but I was there and made the decisions I did and would make the same decision in the same situation. Like an airplane pilot will tell you, any landing you can walk away from is a good landing. Any dive you can walk away from is a good dive and this was a good dive. If nothing else it was a good training dive.
