Hand-Tight Second Stages

[Capt Jim Wyatt]

I hate it when people subscribe to a certain philosophy,and it can't be altered or changed unless it is done by the leadership of said philosophy.

Can you spell DOGMA.

 

[LiteHedded]

Exactly. Increased mechanical complexity in a system is seldom a move in the right direction. This is especially the case when the increased complexity adds an item that can fail and cause issues on any of you dives when it will only prove useful in the event of a very rare or unlikely event. The cost benefit analysis just does not support that approach.

I had a team mate who had a slight freeflow in a tight, silty tunnel. The viz was just good enough to see the team mate take out the reg, and as they did so I was thinking "don't bang on the reg to fix it!" when they banged on the reg to fix it and got a full on freeflow that then required a valve shutdown and blew the rest of the viz.

As an aside, and related to the "don't add uneccesary complexity on a dive" argument, I am glad the team mate did not try to remove the face plate to fix the reg under water. It probably would have worked, but it was totally not required given that we were exiting and given that we had used proper gas management. There was more than enough gas in the remaining tank to exit the cave safely, so there was zero need to try to "fix" the reg, especially in less than optimal conditions.

In that regard, I just don't see the need for removing a face plate under water. Having a failure on entry should result in the team turning the dive, and assuming you are no where near the turn pressure, you will still be fat on gas in either a BM or SM configuration, so there is again no need.

If the failure occurs at max penetration and you were unwise enough to dive to thirds, you might be potentially short of gas and be tempted to try it, but doing so will burn time and gas you no longer have, and you are delaying your teamate(s) as well. By imposing the delay on the tema while you atemptto fix your reg, you are in effect burning their reserve gas as well. In that case, it makes more sense in the big picture to just start the exit and share gas if needed in bigger portions of the cave where it won't materially delay the exit. If there are no bigger portions of the cave, or if you were choosing to dive solo, then you should have been more conservative in the gas planning in the first place.

And to review a previous post, if the reg failed open, you still have the feathering option and stand to lose that option to access gas if your "fix" is not successful.

Conseuqently, when you look at all of the options, pros, cons and consequences, there is seldom if ever any need to remove the face plate unless you are nearing the end of a list emergency options. At thr risk of getitng flamed, I'll suggest those who have done it were perhaps too quick to jump on that particular option, may not have considered the big picture and may have made a better descision by staying with the planning and emergency optiosn they were trained to use.

Finally, prevention makes a lot more sense. Putting the second stages in a nylon stocking will keep any particles large enough to cause problems out of them, and will still let you breathe off them with no delay if needed. Given that the suggestion came from a diver who has been sidemounting for 35 years in tighter and nastier stuff that I have yet done, I give his advice a lot of weight.

there are points in the dive where you just can't "turn around and go home". I recall a failure at the first gas switch with an hour and a half to go. I think this was one we used the wrench on. but I was glad we had it.

I had a reg get all gunked up at cow in the entry restriction once. we shut down the valve and exited to open water, popped the faceplate off and got the gunk out. then continued the dive.

obviously there are points in dives where you don't want to be disassembling the reg.

but like everything else, it's a tool in the toolbox.

and having a wrench in your pocket or regs that can be disassembled easily and cleared out isn't just useful in the water. it can be handy in the parking lot, or just after you splash when you notice problems at inopportune times

 

[Doppler]

Can you spell DOGMA.

Yes, Jim. It's spelled: CLOSED-MINDED IDIOCY.

But I am not sure if that is the Brit or American spelling!?

 

[Trace Malinowski]

Sometimes by doing these practices we also create our own failures. I was demonstrating to a class how I can easily take my regulator apart during our surface discussion. Underwater, my regulator began breathing more and more wet. I took it apart underwater and reseated the diaphragm. Worked great!

It's good to know that I can fix things, but if I left well enough alone more often I probably wouldn't need to fix them.

 

[Jim Lapenta]

I would add people who will beat on their 2nd stage to get it to stop free flowing. Abusing life support equipment to make it function better-does anybody do this to Grandma's pacemaker?

Of course not. Everybody knows a good rap just above it with her cane will usually do the trick. All of my seconds are tight on the hose. They also have removable face plates. And twice I have seen it come in handy. Once with me when the exhaust diaphragm got twisted under and no matter how hard I exhaled it would not seat correctly. It looked fine but I ended up replacing it any way. Another diver had his octo get clogged with duckweed in catfish hotel.it had worked its way into the vents and was putting extra pressure on the diaphragm. None of these were overhead dives however and the fix was done in clear water. I would not try it in poor vis or in a wreck. I don't do caves so no input there. In one of those cases the dive is over.

 

[DA Aquamaster]

there are points in the dive where you just can't "turn around and go home". I recall a failure at the first gas switch with an hour and a half to go. I think this was one we used the wrench on. but I was glad we had it.

I had a reg get all gunked up at cow in the entry restriction once. we shut down the valve and exited to open water, popped the faceplate off and got the gunk out. then continued the dive.

obviously there are points in dives where you don't want to be disassembling the reg.

but like everything else, it's a tool in the toolbox.

and having a wrench in your pocket or regs that can be disassembled easily and cleared out isn't just useful in the water. it can be handy in the parking lot, or just after you splash when you notice problems at inopportune times

I agree having a wrench along makes sense, and provided you have a third reg available to donate a second stage, swapping the second stage underwater is something I'd consider before taking one apart. It's harder to lose a whole second stage.

A small cresent wrench does not take up much room in a pocket and in addiiton to a second stage swap, it will let you access the gas in a stage or deco bottle in the event you lose or break the knob.

Working on a reg in the parking lot is a different issue entirely. I think at the cave/tech level of diving, the average diver is well served by knowing enough about his or her equipment to perform basic field repairs.

 

[LiteHedded]

your point about the r390 type regs is a good one. I wouldn't want to be disassembling a reg like that underwater. I can barely get that ring back in when i'm sitting in my garage, let alone hovering in the water somewhere.

all my second stages are g250s though now. (and a new hot pink one wating for me at home )

 

[Tegg]

Because you're adding quick disconnects to something that rarely needs to be quickly disconnected. I don't like to add issues to my gearif I can avoid it.

One rarely needs the isolator valve on doubles... yet it still is in place... why?

The benefit of my second stages having QDs on them outweighs the "complexity" of adding it. All of my "air inputs" all use the same QD fitting. As such, when I am diving my RB or OC, I can use the same regs and same configuration at all times. I also have access to all of my gas that I carry no matter it's intended use. I can use bailout bottles as diluent, or use my onboard O2 for deco in OC, I can also use any gas supply I have with me to plug into my BOV quickly should I need to swap from the current diluent supply.

I also carry a spare 2nd stage with me in my drysuit pocket when scootering and going a long ways into a cave since having to "feather" a tank for a 6K ft ride is not fun.

There is no way to repair a ripped 2nd stage diaphram. Since I have had it happen to me in the cave, I know what it does and how it affects access to gas.

 

[Cave Diver]

All of my "air inputs" all use the same QD fitting. As such, when I am diving my RB or OC, I can use the same regs and same configuration at all times. I also have access to all of my gas that I carry no matter it's intended use.

So you have the same QD fitting on your second stage that you use on your wing and drysuit inflation? Any issues with flow delivery?

I could see a value in having a QD second in a drysuit pocket on a long penetration if it could just be plugged into an inflator hose and provide adequate gas. Not sure I'm convinced enough to do it on all of my seconds though.

 

[Tegg]

So you have the same QD fitting on your second stage that you use on your wing and drysuit inflation? Any issues with flow delivery?

I could see a value in having a QD second in a drysuit pocket on a long penetration if it could just be plugged into an inflator hose and provide adequate gas. Not sure I'm convinced enough to do it on all of my seconds though.

I have it on all places that use a gas input.

I have dove in many places with high flow and still could breathe fine. I have not seen a reason to remove them yet.