Hand-Tight Second Stages

[ucfdiver]

I've been hoping the leaving the 2nd stage finger tight would die along with using the power inflator as an emergency breathing device.

It's a great idea on paper. I did it for about 2 years until I had my second failure.

 

[Rainer]

I keep my second stages tight (to the LP hose), but I do have faceplates that can be (relatively) easily unscrewed underwater (no tools). I've had to do it once, just past the surf zone, in heavy surge, when my wife's primary was leaking after getting full of sand from a pounding surf entry. It wasn't hard to open and clean, and I had it working in about a minute. Sure, we could have exited through the waves, walked across the beach, up a bunch of stairs, back to the car, fixed it there, then come back, and gone again through the surf, but instead we solved the issue in the water.

Having second stages with easy to access faceplates, that also contain few removable parts, made this doable.

 

[Doppler]

I have never subscribed to the practice of having one's life-support system tinkered with so that it can fall apart or leak at the drop of a proverbial hat. There are still divers who feel that only hand-tightening their second stages to the LP hose is a supportable practice, but thank the gods of free-flowing regulators, they are becoming fewer and fewer.

 

[rjack321]

IIRC Joe Steffen died when his 2nd stage came undone and he embolized somewhere in that chain of events. Maybe Doppler knows whether he was a "hand-tightener"?

While I can imagine it was considered a "good idea once upon a time", just like using metal to metal stage connections, times have changed.

I've always used a wrench on mine.

 

[Tegg]

Why do this when there are nice stainless QD options?

All of my second stages are QD to the hoses... I can swap second stages in seconds...

 

[PfcAJ]

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.

 

[karstdvr]

I have never subscribed to the practice of having one's life-support system tinkered with so that it can fall apart or leak at the drop of a proverbial hat..

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?

 

[DA Aquamaster]

Having second stages with easy to access faceplates, that also contain few removable parts, made this doable.

This is the key element here.

Since so many divers still seem to be stuck on the idea of removing the cover to clear a second stage, it's worth shifting the focus to a discussion of the pros, cons and risks involved rather than just a black/white, good/bad approach to the process.

I'd prefer people who might consider it be fully informed and thenbe abel to make a better decision about whether it may or may not be an option for them.

There is a noteable difference between doing it in a low flow cave versus a high flow cave versus mid-water in a deep ocean dive. Doing it in a tight, silty cave in zero viz would add another element that might put it beyond the ability of many divers who would try it, especially if they had not practiced it.

How good an idea it is also depends on the type of failure. If the lever is blocked so the reg has failed closed, you are not losing anything by trying to clear it as you have no way to access gas with that reg in its present condition.

However if the reg has failed open, you have more to lose. If the diaphragm is lost, torn or is not correctly seated, the reg will flood and you have now converted the problem to one where the second stage cannot be used to acces the gas by feathering the tank valve. The concept of "above all else, do no harm" should apply here.

As suggested above, some regs are more amenable to this procedure than others. Many regs with removeable faceplates have two part face plates (usually an inner purge button/cover and an outer ring). That is not a bad thing, unless the cover must be properly indexed before it can be re-assembled.

The second stage may also utilize a friction ring that both holds the diaphragm in place and prevents it from being twisted when the cover is screwed on. That adds a part that can be lost and in some designs it also must be properly indexed adding to the difficulty of doing it in open water or zero viz.

Some covers also use fairly fine threads that are easy to cross thread, and some cheaper second stages have poor dimensional tolerances that increase the cross threading potential.

The Scubapro R295/R380/R390 come to mind as bad choices in terms of indexed friction rings as well as 2 piece indexed purge covers.

The S600 is slightly better as the cover is easier to index.

The G250 and G250V have a one piece faceplate and a non indexing friction ring, that actually works well to hold the diaphragm in position while you screw on the cover.

Some other brands use a friction ring that does not have tabs to hold it and the diaphragm in place. Those are problematic as they are easier to lose in the assembly process and if lost, may not allow the cover to place enough pressure on the diaphragm to keep it sealed.

Some Dive Rites and similar second stage clone designs utilize a non indexed 2 piece cover where the rubber portion serves as a non-indexed frinction ring. They also have a comparatively rigid diaphragm that sits securly in a fairly deep groove in the case. They are, overall, probably the best bet for in water disassembly as the diaphragm is easy to seat, is less likely to improperly seat, and it is easily held in place by the rubber purge cover. And in the event the outer ring is lost, the dipahragm and cover could still be help in place by hand resulting in a useable reg.

So the take way from this needs to be that what second stage you are diving and how it is specifically designed has a big impact on how practical it may be to remove and replace the faceplate under water.

 

[Doppler]

IIRC Joe Steffen died when his 2nd stage came undone and he embolized somewhere in that chain of events. Maybe Doppler knows whether he was a "hand-tightener"?

While I can imagine it was considered a "good idea once upon a time", just like using metal to metal stage connections, times have changed.

I've always used a wrench on mine.

Joe had indeed picked up the habit of diving with his second stages hand tight. The dive operations officer (a cop just like Joe) remarked on this the day Joe passed away. The practice was specifically counter to the expedition's gear guidelines which is why the DOO noticed it.

Cannot say exactly what happened to Joe, but when we recovered him and his kit, there was a second stage missing... however, we are still waiting for the RCMP report. Four years and holding!

Anyhow, like I said, NOT a fan of ****ing around with life support systems in the water... or "fixing" 'em so that underwater tinkering is an option.

 

[DA Aquamaster]

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

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 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?

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.