The RIGHT thing to do in a blackout.

[Frosty]

The senario is. Lake dive. Actual lake bottom is at 180 feet. There are 3 distinct and sharp thermoclines. at 30 60 and 90 feet.Temps start at 15 degrees but drop sharply at the first thermocline At the 90 foot thermocline the combination of temp/pressure creates a distinct and clear "fake bottom" almost making it look like you are as deep as you can go.
Dip your fin into it and BANG almost instant blackout as the disturbed water/silt mixes with the water above it.
So now you are at 90 feet. Cant see hand in front of your face and can't even see your own bubbles.
First reaction is to look for your dive buddy who although close by instantly disapears.
In looking for your buddy your sense of direction has gone and you can't read your gauges the blackout is that complete.
You have got yourself there. What would YOU do to get yourself out of the situation?

 

[Some X Dry]

Sounds like you dive in the Grotto down the street from my house.. Hudson Grotto, Hudson FL. Assuming the conditions and what-ifs were discussed and proper gear selection made during the pre-dive briefing, I would call the dive, locate and deploy either my lift bag or SMB from depth then begin a slow ascent up the line do safety stop then surface. Buddy should have done the same.

Is the water brackish? Ice-tea colored where all daylight is lost at 40ft and requires lights?

Is the water brackish? Ice-tea colored where all daylight is lost at 40ft and requires lights?

Statement made because water conditions at Grotto require 2 light minimum. I always have 2 lights on all dives.

 

[jar546]

Should have had lights for a freshwater dive that deep. Agree, SMB & slow ascent with safety stop. Dive should have been called.

 

[DevonDiver]

Hopefully (knowing the risks at a particular dive location) my buddy and I will have established a protocol for that eventuality.

Failing that, you've essentially got yourself into a 'lost buddy' scenario. Even if you know your buddy is near - if you can't see them, then they are 'lost'. Standard protocol for that is to search for 1min, then abort and ascend. Chances are, if both divers adhere to that protocol then shortly into the ascent the viz will improve and you'll be able to re-unite and continue the dive.

Zero viz isn't a problem, providing you keep your head. If you have good situational awareness, then a rapid loss of viz isn't catastrophic. You'll know your air pressure, depth, location and direction/distance of buddy... which gives you a starting point towards a quick resolution.

 

[Quero]

I would likely ascend above the silt-out/thermocline and look for my buddy's bubble trail (and, I would hope, light beam, once s/he also ascends) for the requisite one minute. Once reunited with my buddy, either in mid-water or on the surface, we would then decide whether to end the dive or to continue at a shallower depth. It's important to discuss these procedures before the dive, particularly if you know that the dive site is prone to conditions like this.

 

[ianr33]

Follow my line back out. Wouldn't worry about the lost buddy too much as we are both diving redundant gear and he's on the exit side of the reel.

 

[Jaydubya]

I would do the following 4 things: Stop. Breathe. Think. Act.

1. Stop all movement.

2. I'm still breathing and I had plenty of gas when this happened so I have a lot of time.

3. Should I shoot a bag? No way!!! I don't practice this skill with my eyes closed and why should I add entanglement and runaway ascent risk to this equation? I was at 90 ft and bottom is at 180 so I'm not going to use the bottom for reference. Maybe I can ascend above the silt cloud. I bet it doesn't go all the way to the surface, surely not above the first thermocline. I don't want to kick and stir up more crap so I have to become positive but be careful of run-away ascent. That's the plan. Hopefully the silt clears while I am thinking but if not...

4. I become slightly positive by expanding my chest or even adding a small burst of air to my BC if necessary. If I can't see my computer even when backlit against my mask I listen to what my ears (and the pressure in my mask) tell me about how fast I'm ascending. Good. Starting to see some bubbles now. Slow down. I'm above the silt cloud. I re-establish neutral buoyancy and look for signs of my buddy for one minute and then make a normal ascent. If my buddy stays missing for too long I notify emergency services of the missing diver.

Afterwards, I would try to apply my new experience and not dive 90 feet at this location without being prepared for zero vis as a possibility.

 

[TSandM]

What I learned in cave training is that no matter how confused YOU are, your bubbles go up. If you can't see them, you can feel them. They will tell you what orientation you have in the water, and your ears will tell you if you are going down (mine give me no information about going up, although I understand some folks' do). In your scenario, I would stabilize and control my breathing (first imperative). I would check my orientation, and I would fill my lungs and slowly ascend out of the disturbed water. Once out of it, I would, as Quero said, look for my buddy's bubbles (or in my case, his light as well, because I would NEVER be that deep in a place where limited viz was possible, without a good light). If I could not reacquire my buddy, I would execute the "lost buddy" protocol.

The most important thing about zero viz is to remain calm. Control your breathing, and control your buoyancy -- you were neutral when it happened, so if you don't change anything, you should remain neutral. Reflect on the best way to get out of the zero viz situation, and do what's necessary, calmly and methodically.

BTW, I have been in haloclines and thermoclines, and have never found one where I couldn't see my gauges. On the other hand, one can descend INTO the bottom sediments in Lake Washington, and that's real zero viz!

 

[Some X Dry]

Follow my line back out. Wouldn't worry about the lost buddy too much as we are both diving redundant gear and he's on the exit side of the reel.

Um... You would be running a line in a lake at 90ft OW? Do however see a flame.

 

[Some X Dry]

Based on my experience with silt out dive locations in mid water rising up to clear the cloud could cause a collision with an angled overhead. In which case deploying am SMB or lift bag in zero vis IMO as well as others is appropriate. In the case provided with no chance for overhead (In a lake), attempting to rise above such cloud would of course be another alternative. However, it is still of my opinion deploying a SMB or Lift Bag in OW in zero vis presents risks I am willing and aptly trained to deal with. Black-out mask bag deployment is instructed by some even though not required by minimum requirements.