Low/No Viz bottle management

[kanonfodr]

I was talking to a local tech diver this weekend when we were diving together and the subject of deco bottle placement came up in relation to low viz/no viz deco bottle management. He told me that he uses Lean Left, Rich Right where he places his 50/50 bottle on his left side and 100% on the right so it's not an issue for him.

Knowing that we place all of our bottles on the left side but not being technically trained, I didn't quite have a snappy DIR comeback for that idea and while it makes sense from a differing standpoint it is not in accordance with DIR practice. So what is the DIR solution to making sure you get the right bottle when the viz is measured in millimeters?

Peace,
Greg

 

[nadwidny]

... when the viz is measured in millimeters?

And when would that happen?

 

[ucfdiver]

I was talking to a local tech diver this weekend when we were diving together and the subject of deco bottle placement came up in relation to low viz/no viz deco bottle management. He told me that he uses Lean Left, Rich Right where he places his 50/50 bottle on his left side and 100% on the right so it's not an issue for him.

Knowing that we place all of our bottles on the left side but not being technically trained, I didn't quite have a snappy DIR comeback for that idea and while it makes sense from a differing standpoint it is not in accordance with DIR practice. So what is the DIR solution to making sure you get the right bottle when the viz is measured in millimeters?

Peace,
Greg

Ask him how that works on a 3 deco gas dive, or a stage dive with 2 deco gases. Such a silly idea just doesn't hold water in the real world.

Here's a video of viz that's a few feet. There's simply no way I would dive in viz worse than this, and by the time you get to your deco bottles, you will have swam out of it.
http://vimeo.com/9265141

You have to remember as well, if you can't see the label on the bottle, you can't read your depth gauge to verify you're at the switch, you can't read the SPG to ensure you've turned on the correct bottle, and you can't watch your buddy to ensure he doesn't have issues after upping the ppo2. It's not a good idea to be switching gases in no viz if you don't need to. Incorrect gases are the #1 killer of tech divers, no need to play around here.

And when would that happen?

Never. Question #2 is if it did happen, why would you dive for recreation in those conditions?

 

[Rainer]

What does your friend do if he put his bottles on wrong?

 

[ucfdiver]

What does your friend do if he put his bottles on wrong?

oxtox or get bent.

 

[PfcAJ]

If you can't see your MOD, you can't see your depth gauge or watch either. Its a made up scenario.

 

[kanonfodr]

Ask him how that works on a 3 deco gas dive, or a stage dive with 2 deco gases. Such a silly idea just doesn't hold water in the real world.

Here's a video of viz that's a few feet. There's simply no way I would dive in viz worse than this, and by the time you get to your deco bottles, you will have swam out of it.
Minor siltout... on Vimeo

You have to remember as well, if you can't see the label on the bottle, you can't read your depth gauge to verify you're at the switch, you can't read the SPG to ensure you've turned on the correct bottle, and you can't watch your buddy to ensure he doesn't have issues after upping the ppo2. It's not a good idea to be switching gases in no viz if you don't need to. Incorrect gases are the #1 killer of tech divers, no need to play around here.

Wow...that video had me breathing hard while I was sitting in front of my computer with pretty much unlimited viz all around me.

He takes the stance that you can always place your depth gauge right up next to your mask and see it, same with the SPG on the pony bottle. As for ensuring that the proper bottle is on the correct side, I hope that is a part of his pre-dive check when doing deco dives. Watching his buddy...it wasn't a part of the conversation at the time. Same thing with multiple stages or deco gasses, did not come up in the conversation. I was mostly in receive mode as I really don't feel like speaking outside of my training.

So ucfdiver mentioned either not diving/aborting the dive if conditions are that bad, or trying to swim out of it. Both are valid options, IMO, and I've not enough experience in silty environments to play devil's advocate without making people angry but would enjoy it if the discussion continued as I will keep checking in. Surely someone has been in a soup that it was probably not possible to swim out of but yet they were at their switch depth. Or possibly a lights-out cave exit??

Peace,
Greg

 

[PfcAJ]

I've done a few low vis gas switches (on stages), and its no biggie. Most silt-outs will settle within a few minutes if you chill out, and a 6-light failure in a cave is well...a rarity.

Spending a minute or two waiting for the vis to clear is time well spent if you have to switch to a deco gas. In all the cave diving I have done (30+ caves), I've never had to do a true zero vis deco gas switch.

 

[Trace Malinowski]

If you can't see your MOD, you can't see your depth gauge or watch either. Its a made up scenario.

There are caves in which you can start a dive in zero visibility and descend in touch contact until you find turbid or clear water. We are exploring something like this now. But, we've yet to require deco gases.

I learned to identify all my reels, spools, arrows, non-directional markers, and bottles by touch in my NACD cave class.

A diver may find himself without a mask and perhaps separated from his team. In that situation, being able to identify a bottle by feel will put you on the right gas. Having a knotted line will allow a diver to send up a DSMB and measure the stops. I use one knot every 10 feet through the deep stops, 2 knots at the 70 foot gas switch, one at 60 feet, one at 50 feet, 4 at 40, 3 at 30, 20 at 20, 1 at 10.

During your descent, you can also look for markers on anchor lines, mooring balls, and in caves that will help you identify depth by touch. These might be anything from a log in a cave to a splice in a line. If you ascend without a mask or buddy, you can use such tools to approximate your depth.

Approximating time is as simple as, "1 Mississippi ... 2 Mississippi ..."

I make all my AOW, deco, trimix and cave students do such an exercise for the confidence-building.

Finding yourself in a no visibility stage situation isn't far-fetched. Finding yourself in a no vis deco situation is less likely. By rights, your team should be with you to see you through, but you never know what might happen. Getting out of a deco situation without being able to see the gauge or the bottle is as easy as typing a few knots, rushing the QB in two-hand touch football, and being able to tell which bottle is which by feel.

This certainly doesn't mean a DIR diver should place bottles on the right, but a DIR diver should be able to deal with all no vis situations effectively.

 

[Sas]

If you can't see your MOD, you can't see your depth gauge or watch either. Its a made up scenario.

Why does training involve dealing with low visibility situations then? It's not a made up scenario, I have been in plenty of low viz situations and a handful of no viz situations (not inches of viz, but zero viz) - there are ways of dealing with them that Trace has summed up well.