Stage Dropping

[Trace Malinowski]

Trace, your procedure seems very thorough, but how do you make 100% sure the bottle is yours in zero viz? I've seen comments elsewhere of people dropping bottles on other peoples lines (which is obviously a bad idea for several reasons). If you're coming back in zero vis and expecting to find your bottle, but run across someone else's first do you think they're more prone to mistake it for their own? I think people are more likely to have similar bottles/valves than bottle/valves/regs, so identifying the bottle only still leaves some room for error.

I realize that coming back in zero vis, finding someone else's bottle on your line, etc. is starting to get into LHOTP scenarios and is unlikely for 90% of cavers. But pontificating about worst case behind a keyboard is better than "oh shit, what do I do?" in the water.

John, it is really no different than returning to a jump or gap and feeling for your spool. My spools are notched and my bottles are marked so that I know them by touch. While it is not 100% certain that another diver hasn't marked his bottles in the same manner, the statistics of that being the case at the same time, in the same cave, on the same day, in zero visibility are in my favor. Having something distinctive on a bottle just in case that happens is a lot better than returning to a generic bottle.

Trace,

The HILL400 is an area where even less than 1/3 of normal starting back gas would get a diver to his exit. Can you explain why you teach your students to blindly get on a stage bottle rather than exiting with their existing back gas, then switching to the stage when the (simulated) viz improves?

James, it's a class exercise about being able to identify jumps and bottles by feel and perform switches when seeing them isn't possible. It's more about building confidence in one's ability to return home and deco out without being able to see. I would have the student complete the entire exit in a blackout mask, but I return the mask so that we can prevent undo damage to the cave and unnecessary wear and tear on the line until we are nearing the exit in the gallery. Where this could possibly happen would be a solo night dive with a lights out exit. I have a little trick to prevent me from ever being lights out on a solo night dive. I carry glow sticks in my pocket and activate one prior to the dive.

I've swapped stages while on the line more than a few times. I still think that persistent zero vis is incredibly hard to come by, however. Everyone is in such a rush when waiting a minute or swimming out of the silt cloud would fix everything.

The thing is to CHECK YOUR MOD before you switch, each and every time. Even on stages. I used to think that on stages it was nbd one way or another, but I feel a bit differently now. You've got to look at that sticker and check out your buddy for any shenanigans before hittin the trigger, each and every time. Look at stage drops as natural pauses in your diving, make sure everything is squared away, then continue your dive.

And all this 'by feel' and 'by color' stuff goes out the window the second you have to borrow a tank from your buddy, or swap out a reg.

Color helps, but isn't reliable. When hoses are a different color it does make it easier to visually check that your buddy is on the right bottle because you can see the routing of the hose very readily. You can do it with all black, of course. But, it's pretty easy to see a yellow or green hose coming from a bottle and routing to a diver's mouth. True, relying on this method opens the door to problems as bottles change hands.

If you handed me a bottle it would be very simple for me to attach something to that bottle to allow me to identify it by feel. If you handed me a bottle in the water, I could attach cable ties and hair ties that I keep in my wetnotes in places that no one else would most likely have placed them and remove them after the dive.

 

[LiteHedded]

that's why my braile depth gauge is so great for zero vis gas switches. come on...

 

[Cave Diver]

John, it is really no different than returning to a jump or gap and feeling for your spool. My spools are notched and my bottles are marked so that I know them by touch. While it is not 100% certain that another diver hasn't marked his bottles in the same manner, the statistics of that being the case at the same time, in the same cave, on the same day, in zero visibility are in my favor. Having something distinctive on a bottle just in case that happens is a lot better than returning to a generic bottle.

Thanks for the explanation. I would agree that distinctive features would make it easier to identify bottles by feel, but a certain reg could just as easily be that distinctive feature.

I agree with AJ that most of the "feel" issues would be resolved by just settling down and waiting a few minutes for viz to clear a bit for the stuff most people dive.

 

[Cave Diver]

that's why my braile depth gauge is so great for zero vis gas switches. come on...

Oceanic Data Mask.

 

[rjack321]

At this talk of zero vis switching is crap. I'm sorry, but you are making up **** to justify all these layers of feeling, touch whatever for a situation which does not and has not existed. Nobody has (probably ever) died in a cave or otherwise because they switched to the wrong gas in zero vis from failing to read the bottle.

People have died and will probably continue to die because they take shortcuts with the basics: analyzing the gas, 3" high MOD letters, checking themselves and then having a buddy verify the switch.

 

[CyprusSeb]

At this talk of zero vis switching is crap. I'm sorry, but you are making up **** to justify all these layers of feeling, touch whatever for a situation which does not and has not existed. Nobody has (probably ever) died in a cave or otherwise because they switched to the wrong gas in zero vis from failing to read the bottle.

People have died and will probably continue to die because they take shortcuts with the basics: analyzing the gas, 3" high MOD letters, checking themselves and then having a buddy verify the switch.

I think there is some confusion in this discussion between identifying ones tanks as their own in low/no vis vrs swapping gasses/tanks in low no/vis. No matter how sure I am that this tank is mine, I won't swap gasses unless A. I'm out of gas elsewhere and am about to die B. I visually see that this is the bottle I want to swap to. Even with lights out my shearwater gives me more than enough light to read an MOD label...if silt is the problem I'll just wait.

 

[Dive-aholic]

The HILL400 is an area where even less than 1/3 of normal starting back gas would get a diver to his exit. Can you explain why you teach your students to blindly get on a stage bottle rather than exiting with their existing back gas, then switching to the stage when the (simulated) viz improves?

A buddy team is air sharing because of an air loss by one of them. They are doing a stage dive. When they get back to their stage cylinders, the OOA diver is better off to get on his stage cylinder than to continue to breathe off his buddy's long hose. An OOA situation could result in zero visibility. If you have a 1st stage go, you're not going to be hold perfect buoyancy and rim with 2400+ pounds per square inch blowing out of it in a jet stream. You might just muck things up. I know someone (and I'm sure you do too) who had a 1st stage failure causing a roll through the cave and zero visibility during the valve shut down.

At this talk of zero vis switching is crap. I'm sorry, but you are making up **** to justify all these layers of feeling, touch whatever for a situation which does not and has not existed. Nobody has (probably ever) died in a cave or otherwise because they switched to the wrong gas in zero vis from failing to read the bottle.

I was at Twin a few months ago with a cavern class. We went into the cavern, did some drills, and did an OOA exit. My students stirred things up a little, but that's normal there and it usually clears up enough in less than 5 minutes. As we were about to re-enter the cavern, there was a 3-man scooter team exiting the cavern in a huge cloud of silt. It was so bad 2 of them left their scooters clipped to the line in the cavern. We waited over half an hour and the cavern never cleared up. We couldn't even see the log over the entrance. I finally found the log and followed my student's primary line (I have them run a line back to the stop sign) to the reel to retrieve it. Visibility was zero the entire time. Apparently, they had blown out most of the Subway Tunnel with their poor scootering. Granted I wasn't doing a personal dive at the time and didn't have any decompression cylinders with me, but I easily could have been. My personal dives in Twin usually end up with 20+ minutes of decompression on 100% O2. You calculate how much decompression that would be on 32% (my bottom mix). I would have been doing a zero visibility switch. Call it what you want, but I've seen conditions that justify having tactile identifiers on my decompression cylinders, and that was in a tourist cave!

 

[SuPrBuGmAn]

The last time I did 20+ min of deco in Twin(on 32%), my dive buddies flipped me the bird for telling them we probably didn't need to bring O2 - LOL


I peed myself alot on that deco.

 

[ucfdiver]

A buddy team is air sharing because of an air loss by one of them. They are doing a stage dive. When they get back to their stage cylinders, the OOA diver is better off to get on his stage cylinder than to continue to breathe off his buddy's long hose. An OOA situation could result in zero visibility. If you have a 1st stage go, you're not going to be hold perfect buoyancy and rim with 2400+ pounds per square inch blowing out of it in a jet stream. You might just muck things up. I know someone (and I'm sure you do too) who had a 1st stage failure causing a roll through the cave and zero visibility during the valve shut down.

I'm not sure if you're talking about me or not (I zero'ed a cave, and broke the line while grabbing it) during a 2nd stage failure. If it is, anyone here is more than welcome to discuss it-- I'd rather have someone think I'm an idiot than hear someone died that could have made better decisions after considering my mistakes. Never the less, I exited under my own power and sharing gas was never even a consideration, even with the 5 minute delay looking for the lost line. I could still see 2-3 inches, I just couldn't find a line that had been blown away by the flow and landed in poofy silt. Had we been stage diving, the extra gas in my remaining tank would have gotten me to the point where viz cleared up. The real issue here was that I was diving side mount, which is a dangerous gear configuration from a gas management standpoint, but required for that dive.

Also IMO getting a OOA diver with elevated SAC onto a stage bottle is *not* the right answer unless the cave is shallow and a stage lasts quite a long time. Give the smaller bottle to the diver without a failure, because with the elevated SAC, the OOA diver is going to be OOA again shortly. Putting him on back gas is best, and allow the diver without a failure to manage the stages.

I was at Twin a few months ago with a cavern class. We went into the cavern, did some drills, and did an OOA exit. My students stirred things up a little, but that's normal there and it usually clears up enough in less than 5 minutes. As we were about to re-enter the cavern, there was a 3-man scooter team exiting the cavern in a huge cloud of silt. It was so bad 2 of them left their scooters clipped to the line in the cavern. We waited over half an hour and the cavern never cleared up. We couldn't even see the log over the entrance. I finally found the log and followed my student's primary line (I have them run a line back to the stop sign) to the reel to retrieve it. Visibility was zero the entire time. Apparently, they had blown out most of the Subway Tunnel with their poor scootering. Granted I wasn't doing a personal dive at the time and didn't have any decompression cylinders with me, but I easily could have been. My personal dives in Twin usually end up with 20+ minutes of decompression on 100% O2. You calculate how much decompression that would be on 32% (my bottom mix). I would have been doing a zero visibility switch. Call it what you want, but I've seen conditions that justify having tactile identifiers on my decompression cylinders, and that was in a tourist cave!

How would you verify depth on 1/3in letters from the dive computer if you can't verify 3in letters on the deco bottle?

 

[PfcAJ]

Its a good thing OOG situations don't happen very often. The IUCRR would be very very busy.