Swapping regs

This is from another thread:

"... independent backmounted twins. If you lose one regulator, you can't get at the gas in that tank, like you could in sidemount..."

Has anyone ever actually done this? I mean, remove a reg from one sidemounted cylinder, hold your breath, remove the other reg, and install it on the first cylinder.

I'm not asking if you think you can do it. I'm asking if you ever did, either in an actual reg-failure situation or in a pool as an exercise.

(I realize the possibility exists where there is a reg "failure" such that the second stage freeflows and a sidemount diver can "feather" the valve open and closed, but this is not what I'm talking about.)

There are several ways to get gas before going that far. "Valving" a freeflowing reg is the simplest (in sidemount anyway). When I took my basic OW class, we had to do a "broken regulator" drill. You can even breathe directly off the tank valve, if it meant saving your life.

No, I have never tried changing regs underwater, but I just might try it on one that is due for overhaul anyway. As you know, not all regulators have the same mechinism in the 1st stage, and some would be a lot harder than others to clear.

I have read reports of it being part if sidemount classes in Mexico and of people doing it, but I have never seen it done in person.

Scott

Russell,
Sidemount divers can access the gas in the independent cylinder by feathering the valve on and off to breathe. This would be next to impossible with independent backmount. Yes I have practiced this and there is a rhythm that you get into. I can even scooter with left or right hands and feather with the other, but it helps if you know the cave well.
I would hopefully never consider switching regs underwater, but I know Andrew has practiced it in the pool. I will let him comment on how plausible it really is.
Dive Safe,

I've done it during deco when my deco-bottle reg failed. I would exhaust all other possibilities first, especially with DIN - nothing is more frustrating that a din valve that just won't start - imagine that while holding your breath! Oh, and remember to re-build the reg's IMMEDIATELY! Don't forget for a few weeks for it to turn green and remove all the chrome on the inside.

If it was fresh, clean, spring water, wouldn't you be fine simply running it for a bit to dry it out?

I have done it once as a practise (I have 3 cylinders) and it is not as easy as it seems. Some regulators will be very hard to recover from the water entry. The presure gauges will be flood also. As I recall UK divers seems to have done it effectively in the past. I think this is a very desperate technique.

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Originally Posted by Greenwood_60

If it was fresh, clean, spring water, wouldn't you be fine simply running it for a bit to dry it out?

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It depends on the design of the regulator.

1. With a flow thru piston design like the MK 10, Mk 25, etc, it would probably be adequate, with the possible exception of the HP ports, but those are easy for the diver to access on their own.

2. With a flow by piston design like the Mk 3, Mk 2 Plus, etc, there is a small hole that allows air to pass to the compression chamber above the piston. However, ther eis very little exchange of air between the compression chamber and the rest of the reg, so once water got there it would be very unlikely to be removed by flowing gas through the reg, especially in on long purge.

3. Diaphragm regs are also more likely to have dead spaces where water may not be easily purged from the reg.

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Originally Posted by FW

There are several ways to get gas before going that far. "Valving" a freeflowing reg is the simplest (in sidemount anyway). When I took my basic OW class, we had to do a "broken regulator" drill. You can even breathe directly off the tank valve, if it meant saving your life.

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The vast majority of regulator failures are of the "fail open" variety where feathering the valve will work well. I have even seen a MK 5 continue to function with a broken mainspring.

The exception to this would be events where the lever in the second stage is blocked by an object that then prevents the lever form opening the valve, or if for some reason the poppet (or shuttle valve) in the regulator is able to jump past the tabs on the lever. This is realistically only likely to happen on a balanced second stage and again either requires a damaged lever, or a foreign object under an arm of the lever that allows it to be lifted enough to release the poppet. And to be fair I have only seen this occur on a single regulator in about 15 years of servicing regulators.

I am glad I have 200 bar Din Valves on my tanks... 300 Bar valves take too long to screw in when I can breathe!

A dip tube getting plugged in a tank I would think would be more common......Especially if its a resort or rental tank, being they dont seem to be maintained as well. I just read somewhere about this happening on two consecutive dives,,,must of been DAN's Mag.

Well, enough people have tried this, that I don't have to. Like Larry said, regs normally fail open anyway. I have had to valve a reg a couple of times. You tend to hold your breath too long, and end up with a headache.

Didn't Jill H. talk about the thought process in her last adventure?

I have done the feathering on off a few times and in fact I do it sometimes during deco to practice it. I have never swapped out full regulators (never 1 st stage) but have switch out my second stages. I dive the same regs on deco bottles (I have many regs now and group them by type). In the great lakes for awhile we only hand tightened the hose onto the 2 nd stage, we'd turn off the gas purge the reg and swith 2 nd stages. ( now just carry a c-wrench in my OH Sh-t pocket). Feathering works better but during real long decos switch 2nd stages is easier. FYI if I swicth 2 nd stages I have reg overhauled and dried. Should be noted I dive 90% in fresh water and never done this in sea water.

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Originally Posted by Slüdge

This is from another thread:

"... independent backmounted twins. If you lose one regulator, you can't get at the gas in that tank, like you could in sidemount..."

Has anyone ever actually done this? I mean, remove a reg from one sidemounted cylinder, hold your breath, remove the other reg, and install it on the first cylinder.

I'm not asking if you think you can do it. I'm asking if you ever did, either in an actual reg-failure situation or in a pool as an exercise.

(I realize the possibility exists where there is a reg "failure" such that the second stage freeflows and a sidemount diver can "feather" the valve open and closed, but this is not what I'm talking about.)

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I did it in the pool. It's doable, but even the smallest mistake will leave you SOL. I'd hate to depend on it but would consider it if there were no other options.

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Originally Posted by FW

You can even breathe directly off the tank valve, if it meant saving your life.

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I learned this skill from watching Sanctum! The movie website refuses to issue C-Cards though.......

-Jon

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Originally Posted by Slüdge

This is from another thread:

"... independent backmounted twins. If you lose one regulator, you can't get at the gas in that tank, like you could in sidemount..."

Has anyone ever actually done this? I mean, remove a reg from one sidemounted cylinder, hold your breath, remove the other reg, and install it on the first cylinder.

I'm not asking if you think you can do it. I'm asking if you ever did, either in an actual reg-failure situation or in a pool as an exercise.

(I realize the possibility exists where there is a reg "failure" such that the second stage freeflows and a sidemount diver can "feather" the valve open and closed, but this is not what I'm talking about.)

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I did it a few times in training, it is very easy to do and if need be and it takes more time than a single Berwyn hold you can breeth of the valve and continue with the reg swap.
Most probably you will never have to actually do this but why not practice it just in case? I find it important no matter how remote the chances are and these two skills do not involve any extra gear but an extra way to use the gas you have in case of a failure.

Steve Bogaerts has his students practice it in his Advanced Sidemount class.Here is an account by a student, toward the end of the article.

Swapping regs? I am all for it. I have 6 Calpyso IV's that I would gladly swap for Dive Rites, Scubapros, or Apex.

Is that quote from Flipper?

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Originally Posted by Slüdge

Is that quote from Flipper?

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No, Flipper is laughing at us for using regs at all.

I'm talking about his signature line.

Yes, but Flipper don't cave dive...

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Originally Posted by Slüdge

I'm talking about his signature line.

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It's one of Douglas Adam's books in the Hitchhikers Guide to the Galaxy series. I never understood the importance of a towel until I read those books.

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Originally Posted by DA Aquamaster

It's one of Douglas Adam's books in the Hitchhikers Guide to the Galaxy series. I never understood the importance of a towel until I read those books.

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Yes, towels are important.

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Originally Posted by OFG-1

Yes, towels are important.

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I like the one you deleted better ;)

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Originally Posted by FW

I like the one you deleted better ;)

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OK

"If there's anything more important than my ego around, I want it caught and shot now."

... and the answer is 42... I love this book!

This is an interesting thread. It would be neat to see someone video their buddy performing this skill in a pool or in clear open water. Then repeat the drill in zero viz. While the second exercise would not be a video, it could be timed for comparison...

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Originally Posted by Xenia

... and the answer is 42... I love this book!

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For one Glorious Year Marci was proud to be the Answer to the Ultimate Question of Life, the Universe and Everything! Then she turned 43.

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Originally Posted by gasdiver

This is an interesting thread. It would be neat to see someone video their buddy performing this skill in a pool or in clear open water. Then repeat the drill in zero viz. While the second exercise would not be a video, it could be timed for comparison...

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Black out the divers mask by placing tin foil over it and you have instant zero viz, but zero viz you can still video tape in.

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Originally Posted by DA Aquamaster

For one Glorious Year Marci was proud to be the Answer to the Ultimate Question of Life, the Universe and Everything! Then she turned 43.

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umm, no. *this* is the year of my glory, the year i'm 42. 5 lashes with a wet noodle!

Phillip: did you rebuild your regs after practicing this skill? Did your spg's get moisture in them?

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Originally Posted by DA Aquamaster

Black out the divers mask by placing tin foil over it and you have instant zero viz, but zero viz you can still video tape in.

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Good point.

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Originally Posted by BabyDuck

umm, no. *this* is the year of my glory, the year i'm 42. 5 lashes with a wet noodle!

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Edit: for one Glorious Year Marci IS proud to be the answer to the Question of Life, the Universe and Everything.

I on the other hand do not know the answer to such difficult questions, nor even the comparatively easy ones - like how old my girlfriend is.

I have a hard time remembering cuz she does not look a day over 30.

What a post to hit 1000 on!

I have used independent singles in the past, early trimix dives in the 90's. The point of them is to plan your dive to not have the gas available in the lost tank during bail out. More importantly is losing a deco bottle, I think. At least a couple of divers I know of retired after getting bent when they lost a nitrox bottle on a deep dive. I always carry extra deco gas for team use if back gas will not bring you to the oxygen. A few years ago, a failure of a second stage exhaust valve rended a tank of 50% usless. I was able to complete deco because I carried a spare back up tank. Last month on a dive in P2 I had an o ring blow on the 50% after two breaths. My dive buddy was dressed and in the truck before I got out, but the normoxic back gas worked fine on that dive. I don't like the idea of switching regulators under water. If I have trouble I just want to go to another source.

good save, babe. you're back in the will.

I have never swapped regulators underwater as it seems like it would be a recipe for further problems. We have trained to swap cylinders on our air packs while our masks are blacked out. The cylinder has to be shutoff and air bled down from the secondary. Then the cylinder conenction is unscrewed, these are 4500 psi bottles with longer valves versus the 2216 so it takes longer pprobably about the same length as a 300 bar DIN. Thenremove the cylinder retainer strap and remove cylinder. Replace cylinder and repeat all steps and turn on air. We often do this after running a drill so we are winded somewhat. We try to hold our breaths while doing this to have a feel for what the person is going through while we change their cylinder out. It is very hard to do. Luckily we have never had to do it in a real situation and hopefully never will. The newer scba has transfill lines so we can equalize pressure between two cylinders. It might be a little easier doing it in the water especially sidemount where the regulator would be in front of the person and hopefully in full view. Hopefully no one will have to try this underwater. Valving the tank would be easier than swapping I think as I have never had to try it.

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Originally Posted by gasdiver

This is an interesting thread. It would be neat to see someone video their buddy performing this skill in a pool or in clear open water. Then repeat the drill in zero viz. While the second exercise would not be a video, it could be timed for comparison...

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I did it in training with my eyes closed (zero viz sim), and in my pool on occasion for good measure with a sacrificial reg, really it is very easy to do, in fact the hardest thing about this drill is keeping good trim during the swap, the actual swap is easy, and if need be you can take a breath of the valve if you need more time (also very very easy to do) this is were breathing off the valve comes in very handy, you can take as long as needed to do the swap, no need to do it in one breath or if take too long

This would be an extreme last resort solution but still a good skill to have, at least if sh!!t hits the fan you would know it is an option and much better than breathing off the valves (the absolute last resort but also doable too).

I took an advanced OW class many years ago where one of the drills was 10 tanks strewn on the bottom of the pool. You had to swim to each tank without a mask and get gas from the tank, get a breath or two and move on to the next. Each tank had it's own regulator with some sort of problem, ex: free flow, no diaphram, no exhaust mushroom valve, leaking water, no 2nd stage but a LP hose to slurp off of, etc. The last tank had no regulator and required valve breathing. I found it easiest to open the valve and create an air plume to draw a breath from versus wrapping my mouth around the valve and opening it.

I have since had to swap out regs during deco from one tank to another in order to access all the planned mixes due to a failed reg enroute to the surface.

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Originally Posted by OutlawCaver

I have since had to swap out regs during deco from one tank to another in order to access all the planned mixes due to a failed reg enroute to the surface.

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I think i watched you do that...was it at diepolder?

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Originally Posted by OutlawCaver

I took an advanced OW class many years ago where one of the drills was 10 tanks strewn on the bottom of the pool. You had to swim to each tank without a mask and get gas from the tank, get a breath or two and move on to the next. Each tank had it's own regulator with some sort of problem, ex: free flow, no diaphram, no exhaust mushroom valve, leaking water, no 2nd stage but a LP hose to slurp off of, etc. The last tank had no regulator and required valve breathing. I found it easiest to open the valve and create an air plume to draw a breath from versus wrapping my mouth around the valve and opening it.

I have since had to swap out regs during deco from one tank to another in order to access all the planned mixes due to a failed reg enroute to the surface.

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I remember doing a similar circuit, not in an advanced OW course though (I guess yours wasn't PADI ;-) ). Good fun. I swapped regs once in the pool. It works...how happy I would be doing it under real stress remains to be seen (or not hopefully).

Cheers, Marc

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Originally Posted by OutlawCaver

I took an advanced OW class many years ago where one of the drills was 10 tanks strewn on the bottom of the pool. You had to swim to each tank without a mask and get gas from the tank, get a breath or two and move on to the next. Each tank had it's own regulator with some sort of problem, ex: free flow, no diaphram, no exhaust mushroom valve, leaking water, no 2nd stage but a LP hose to slurp off of, etc. The last tank had no regulator and required valve breathing.

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Forrest made us do that in cave dive class. 1977.

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Originally Posted by Slüdge

I mean, remove a reg from one sidemounted cylinder, hold your breath, remove the other reg, and install it on the first cylinder.

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Hi Russell,

Which reason to hold the breath?. At least can re-breath from the inflator/ corrugated hose safely for three or four times. In the other hand, removing a DIN first stage underwater is the best way to lose the o-ring (I always carry one extra DIN oring for each second stage; can upload a pic if useful), but...

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Originally Posted by argyris

I think this is a very desperate technique.

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I agree. As read, it is best recipe for serious problems. What reason to change regs with a proper gas planning?

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Originally Posted by Merlin Rhoda

Phillip: did you rebuild your regs after practicing this skill? Did your spg's get moisture in them?

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Good input!

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Originally Posted by Igor Beades

I agree. As read, it is best recipe for serious problems. What reason to change regs with a proper gas planning?

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This is the point I think many divers here are missing. In order for reg swapping to even show up on the horizon as something you might have to do, you have to have a catatrophic gas loss / reg failure on top of improper gas planning or management. So if you need to do it, you've already seriously screwed up on top of having an unexpected failure.

My concern is that a few divers may decide that proper management of SM cylinders (i.e. maintaining enough reserve in either tank to exit or reach your deco gas in the event the contents of the other are lost) is no longer as important as a reg failure becomes something that is manageable by swapping regs.

Indeed it was Bill.

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Originally Posted by wingman

I think i watched you do that...was it at diepolder?

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Originally Posted by phillip1

I did it in training with my eyes closed (zero viz sim), and in my pool on occasion for good measure with a sacrificial reg, really it is very easy to do, in fact the hardest thing about this drill is keeping good trim during the swap, the actual swap is easy, and if need be you can take a breath of the valve if you need more time (also very very easy to do) this is were breathing off the valve comes in very handy, you can take as long as needed to do the swap, no need to do it in one breath or if take too long

This would be an extreme last resort solution but still a good skill to have, at least if sh!!t hits the fan you would know it is an option and much better than breathing off the valves (the absolute last resort but also doable too).

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Phillip,
The next time you practice this drill, get a buddy to video it. Not that I want to see you get slammed or anything like that, but it would generate some interesting comments I'm sure.

I will and I won't get slammed cause I will do it in style, in fact it might even be part of the Sidemount Tips and Tricks vol.2 video, so there.lol...