Have you ever dove ZERO viz?

[Nemrod]

You can read the pressure guage if it is placed directly against the mask and is luminous. Place a light on the guage and then after charging it then hold the guage directly to the glass. A compass, a small bubble type can be sliconed INSIDE the mask. You have to have good eyes to read that close, when I was young I could of course, now, not.

Yes, I have dove in absolute zero visibility many times, mostly various rivers in Louisiana to recover this and that, outboard motors, sunken boats, lost fishing gear etc. Not only zero viz but currents, swirling currents, barge/boat traffic, and often quite deep, got run over by a tug pushing a chemical barge, I was 40 or more feet down and it sucked me off the bottom and spit me up behind the tug--this despite my stabbing my SeaHawk into the bottom to anchor me. Lights generally are of no use in such conditions other than it is comforting being able to see the glow of a powerful dive lamp from two inches away--lol. I always used a J valve, always checked constantly that it was still up in case I could not read my spg, watch or depth guage. No big deal. Made a few bucks which was OK for a college kid on a budget, solo of course so I did not have to split my cash.

N

 

[drivsea]

If you are on the bottom looking for something in the muck there is no real point to being neutral, your not concerned with protecting precious sealife or preventing a silt out and neutral buoyancy will only disorient your sweep pattern. IMO it would be best to get negative and crawl your sweep pattern (perhaps using a downline/sweepline fastened on surface to the top of fountain). Thatsaid you would need to protect your feet w. boots (walmart $10 specials-w steel toes) and hands with gloves that are thin enough to identify the object by feel while protecting your hands from who knows what got chucked in that mire....
At end of dive (w precious fountain spicket tucked securely in biohazard suit) in zero viz it would be best to ascend slightly negative hand over hand on downline so you can reference your 30ft p minute.
Again for such conditions a surface supply (umbilical) would be best because getting caught on some junk on scuba would suck....

 

[Abbo]

Some dive associations require candidates to swim with a blacked out mask as part of the basic O/W tests: BSAC put me through that in '81, though I don't know if it's still required. It's easy to relax when there is somebody tasked to lead you around the pool, and where you can take off the mask anytime things go pear-shaped. For IANTD training my buddy and I had to locate each other in a pool with blacked-out masks. That was trickier, but still reasonably trivial. I also did lost line drills in the dark of the engine room of a wreck for tech wreck: I was oddly calm, becauuse I knew the location of 2-3 torches. Recently I have had viz of 2-3 feet on a number of occasions, with brief periods of zero: I know where all my equipment is by touch, so that's not a problem.

What you describe, though, requires specialist training and equipment, because a silt-out doesn't go away by turning on a light, and you are planning on staying in those conditions to complete a search pattern. As has been mentioned, you need surface-supplied air, a tender rope with a buddy on the surface on the rope; fins off; thorn-proof gloves at the least. Don't think of going down there without a tender rope and someone watching out for you at the surface if it really is zero viz. The situation is significantly different if you have 2-3 feet viz.

 

[Gary D.]

If you are on the bottom looking for something in the muck there is no real point to being neutral, your not concerned with protecting precious sealife or preventing a silt out and neutral buoyancy will only disorient your sweep pattern. IMO it would be best to get negative and crawl your sweep pattern (perhaps using a downline/sweepline fastened on surface to the top of fountain). Thatsaid you would need to protect your feet w. boots (walmart $10 specials-w steel toes) and hands with gloves that are thin enough to identify the object by feel while protecting your hands from who knows what got chucked in that mire....
At end of dive (w precious fountain spicket tucked securely in biohazard suit) in zero viz it would be best to ascend slightly negative hand over hand on downline so you can reference your 30ft p minute.
Again for such conditions a surface supply (umbilical) would be best because getting caught on some junk on scuba would suck....

I have found that it is much more effective using fins on a search than trying to walk it. In heavy silting conditions the bottom can be so soft that trying to walk in soupy oatmeal doesn’t work very well. Just because you’re using fins doesn’t mean you need to be neutral.

If you’re diving dry the majority of dry suit boots aren’t going to fit into the majority of steel toe boots unless you use the latex booties which aren’t a good choice for PSD work.

Why Kevlar gloves?

Gary D.

 

[drivsea]

Agree w. abbo ... 3+ man team is the standard, comms etc. and dont want your rack operator choking hose if you jump your 2nd diver...

 

[Kbear]

The situation is significantly different if you have 2-3 feet viz.

If I had had 2-3 foot viz, it would've been no problem at all. I've done those dives many times before.

But after reading all these responses, I'm really glad I called the dive. Surface supplied air...steel toe boots...blacked out masks...being way negative....way out of my experience range.

 

[Doc Harry]

I dove in zero viz solo last week on Summersville Lake.

A boater came by while I was taking a break on shore between dives. He told me that he accidentally dropped the ladder off his boat and asked me find it for him. He took me over to the cove by boat and said, "Somewhere around here."

The water was only 20 feet deep. Normal viz was about 15-20 feet. But in this area the viz was ZERO! They had stirred up the muddy bottom dredging for the ladder. I tried to methodically search the area but I couldn't even see the compass pressed up to my mask. So I just sank to the bottom and finger-walked around randomly.

After about 10 minutes I ran right into the ladder. Hooked up a lift bag and sent it to the surface!

On the boat ride back to my truck we enjoyed a beautiful sunset on the lake. Until we ran out gas......

 

[Tigerman]

I can say one thing for walking/crawling your search pattern.. In the lake here, many places that could very well mean you couldnt get back up.. NOT something I want to test, especially on SCUBA with no lifeline that can pull me up if I give the signal..

 

[Scuba-Jay]

As a matter of fact I ran into this on Saturday morning. Had been drinking with some friends on a buddies boat Friday night when i managed to fall over the side and into the water (we were tied up to a dock.) Out popped my wallet from my shorts, and with it sunk $200 cash, credit cards. all my IDs, my military clearance card and all kinds of other stuff. I tried diving down and feeling around in the sea grass for a few min but decided it would be better to wait until the next day. That morning i returned to the dock (a commercial fueling dock) with mask and fins and gave it another shot. The second I decended i knew it was a bad idea to be down there without air. no vis (even lost all the ambient light) and lots of nasty stuff on the bottom. All it would have taken was for me to slip my wrist through a disgarded piece of rope in the darkness and id have died. Anyway i got out, ran home, picked up my scuba gear and gave it another try. I never did find the wallet but im sure glad i decided to continue with air on my back.

J

 

[tonka97]

KBEAR,
....Part of the training that we put perspective public safety divers (law enforcement and fire fighters) through, involves dives with thier mask blacked out with tape. Not all can handle it. We call it diving by brail or using "The Force".
trtldvr www.divealive.com

How do you monitor your depth? Other than the new 'heads up display' masks that are coming to the market (already?), seems like you would have to be in touch with the bottom or guide line.