Question Have you (or anyone you know) ever seen a yoke regulator dislodged while diving?

[Vitesse2l]

I dislodged a yoke from my pony on a shore dive, banged it on a rock and then happened to notice the first stage dangling. Unpressurised, and I was experimenting with rigging and position so no intention of using it.

Cost me a reg service. Scubapro Mk2 and r190.

These days I always pressurise a pony or stage as part of my setup checks, then again at the buddy check!

 

[James79]

While I would have thought it would be a highly unlikely event, 7/54=12.9% of the respondents (to date) have either seen a yoke reg dislodged from a charged tank while diving or have had it happen to them directly. While this is just a small dataset I know, that is an unacceptably high percentage IMO for such an extreme equipment issue. I remain a believer in using DIN regs exclusively.

While that is correct on the face of it, through the comments most of the that 12.9% seem to be blown O-rings, not dislodged or bent/broken yoke. This poll is of limited utility when the answers are conflated with a separate issue.... combine that with people seeming to think the poll is whether yoke or DIN is better (not the purpose here), and the results seem to be a little skewed. Of those 7, only 2 or 3 have listed comments that show it may be more than a O-ring or valve maintenance issue (actually an impact dislodged issue) and none have been in water actual damage to the yoke assembly.
I don't care if people prefer one or the other, I'm just trying to drill down into the specific failure mode.

 

[Angelo Farina]

Are yoke regs an American thing? I don't know who came up with the design but I thought it was french since they build the fist regs, didn't they?

Yes, the Yoke fitting was the original design of Cousteau-Gagnan.
The DIN fitting instead comes from Germany.
None of them comes from US.

 

[johndiver999]

Extrusion of an oring could be caused by any of the following or more likely a combination of these factors.
worn oring
improper oring
bent yoke
yoke screw not tightened sufficiently (especially if yoke is bent).
Worn or out of round or damaged valve face/groove
impact to yoke causing movement and or bending of yoke
worn threads on yoke and/or screw

probably others I am not thinking of, so underwater impact that bends or shears the yoke versus all the other failure modes would be hard to distinguish unless there was obvious catastrophic failure.

I've seen orings extrude due to zero impact, just time under pressure.

 

[billgraham]

I remember being a new-ish wreck diver and I pulled out my deco gas reg and the first stage was just hanging from the hose! It was a yoke and I had pressurized it and shut it, and probably checked it a couple of times during the dive.

 

[TylerG.]

So, as I will not be diving any time soon I've decided to conduct a preliminary test on land. I will preface the results by saying two things, firstly it did take more force than I had anticipated, I didn't expect it to turn to mush but it took more than I originally thought, so I sort of accept fault on that part. Secondly, although in previous threads I may have used words like shear etc., I was obviously, or maybe not so obviously exaggerating. The purpose of the test was to try and dislodge, shift, the yoke assembly to a point where it would develop a moderate leak, not a trickle. see the leak here: The regulator was a brass mares mr12dfc


This was after it was struck 2 or so times with a metal tool, on the yoke handwheel, with a force equivalent of 5 newtons, or, wait for it, 1 pound force. Now when I saw this I had the same reaction that your having right now. It didn't make any sense to me either. So here is a good explanation of pound-force I found on quora.

The pound-force (lbf) is defined a bit differently than the Newton. One pound-force is defined. as the force required to accelerate an object with a mass of 1 pound-mass at a rate of 32.174 ft/s2. The number 32.174 comes from the acceleration due to gravity on Earth The pound-force (lbf) is defined a bit differently than the Newton. One pound-force is defined. as the force required to accelerate an object with a mass of 1 pound-mass at a rate of 32.174 ft/s2. The number 32.174 comes from the acceleration due to gravity on Earth A pound is a unit measurement of weight used in systems of measurement. ... An lbf, or a pound force, is the gravitational force exerted by a matter on the surface of the Earth. Thus, it is the force exerted by the mass of one avoirdupois pound. Thus, 1 lbf, or one pound force, can be measured or converted in Newtons.


An lbf, or a pound force, is the gravitational force exerted by a matter on the surface of the Earth. Thus, it is the force exerted by the mass of one avoirdupois pound. Thus, 1 lbf, or one pound force, can be measured or converted in Newtons. For example, 1 lbf = 0.45359237 kg × 9.80665 m/s² = 4.448 N, or one pound force is equivalent to the product of 1 avoirdupois pound and the force which is equivalent to the mass multiplied by the acceleration due to gravity.

I lied, this explanation didn't really help me. Now I tried calculating applied force, impact force, everything you can think of, and they all gave me a similar result. Now I imagine that I hit the yoke with 40-60 pounds of "weight".?.? I don't know anymore this whole physics thing messed me up. If you are a physicist and want to help here are some of the measurements:
Metal tool weighed 3.3lbs, swung with an acceleration of 9 ft/s^2, final impact speed of 3.5 mph, if you want more lmk.

After examining the yoke and valve, it appears the actual sealing surfaces were not significantly damaged, but the whole clamp assembly was bent in such a way that the sealing surfaces could not sit flush together anymore, thus the leak.
I don't know if or when ill do an in-water test, so I'll end on this. Every piece of modern equipment available will work, yoke, bcds, ffms, split fins (that one hurts to say), whatever, it all works. If I can find a better lbf explanation i'll post that, but for now im done, gn.

 

[Angelo Farina]

So, as I will not be diving any time soon I've decided to conduct a preliminary test on land. I will preface the results by saying two things, firstly it did take more force than I had anticipated, I didn't expect it to turn to mush but it took more than I originally thought, so I sort of accept fault on that part. Secondly, although in previous threads I may have used words like shear etc., I was obviously, or maybe not so obviously exaggerating. The purpose of the test was to try and dislodge, shift, the yoke assembly to a point where it would develop a moderate leak, not a trickle. see the leak here: The regulator was a brass mares mr12dfc


This was after it was struck 2 or so times with a metal tool, on the yoke handwheel, with a force equivalent of 5 newtons, or, wait for it, 1 pound force. Now when I saw this I had the same reaction that your having right now. It didn't make any sense to me either. So here is a good explanation of pound-force I found on quora.

The pound-force (lbf) is defined a bit differently than the Newton. One pound-force is defined. as the force required to accelerate an object with a mass of 1 pound-mass at a rate of 32.174 ft/s2. The number 32.174 comes from the acceleration due to gravity on Earth The pound-force (lbf) is defined a bit differently than the Newton. One pound-force is defined. as the force required to accelerate an object with a mass of 1 pound-mass at a rate of 32.174 ft/s2. The number 32.174 comes from the acceleration due to gravity on Earth A pound is a unit measurement of weight used in systems of measurement. ... An lbf, or a pound force, is the gravitational force exerted by a matter on the surface of the Earth. Thus, it is the force exerted by the mass of one avoirdupois pound. Thus, 1 lbf, or one pound force, can be measured or converted in Newtons.


An lbf, or a pound force, is the gravitational force exerted by a matter on the surface of the Earth. Thus, it is the force exerted by the mass of one avoirdupois pound. Thus, 1 lbf, or one pound force, can be measured or converted in Newtons. For example, 1 lbf = 0.45359237 kg × 9.80665 m/s² = 4.448 N, or one pound force is equivalent to the product of 1 avoirdupois pound and the force which is equivalent to the mass multiplied by the acceleration due to gravity.

I lied, this explanation didn't really help me. Now I tried calculating applied force, impact force, everything you can think of, and they all gave me a similar result. Now I imagine that I hit the yoke with 40-60 pounds of "weight".?.? I don't know anymore this whole physics thing messed me up. If you are a physicist and want to help here are some of the measurements:
Metal tool weighed 3.3lbs, swung with an acceleration of 9 ft/s^2, final impact speed of 3.5 mph, if you want more lmk.

After examining the yoke and valve, it appears the actual sealing surfaces were not significantly damaged, but the whole clamp assembly was bent in such a way that the sealing surfaces could not sit flush together anymore, thus the leak.
I don't know if or when ill do an in-water test, so I'll end on this. Every piece of modern equipment available will work, yoke, bcds, ffms, split fins (that one hurts to say), whatever, it all works. If I can find a better lbf explanation i'll post that, but for now im done, gn.

The physical quantity relevant for damaging a structure is the momentus Q (mass x velocity), which is measured in kg×m/s, not the force (either in N or lbf).
The force exerted by an hammer hitting a body is given by Q/dt, where dt is the time of contact between the hammer and the body.
The time of contact depends by the hardness of the two bodies. If they are really hard, the time of contact can be just a couple of ms, making the impulsive force to be very large.
This can be measured using an impact hammer, which has a load cell on its tip.
I have a couple of them in my lab. Here one of them, by Bruel & Kjaer:

Impact Hammer | B&K Type 8206 | Brüel & Kjær

Impact Hammer type 8206 is designed for exciting impact forces on small/medium structures such as engine blocks, car frames and vehicle components.

www.bksv.com

 

[Rich1280]

Just seen this thread. I saw one failure of a pressurised yoke set up, single 15 on a bcd. It fell from bench to deck due to rolling dive boat in a mild cross swell. Impact was onto the floor with the body of the first stage and the boot of the cylinder on the bench still. I guess it could be described as rotational, but the first stage effectively lifted on the face of the valve and leaked. Was loud enough to make most of us jump, and I'm not sure if it was fixable as the diver sat out the dive.
Rich

 

[Moerae]

If the majority of people doing the types of dives where dislodging the reg is a concern are diving din (e.g. advanced penetrations), then we wouldn't expect to see many instances of anyone seeing regs get dislodged.

I appreciate the sentiment behind the poll but it likely won't be too insightful due to this problem. Banging and wrenching your regs against things around you really only happens to a very small minority of divers and we aren't diving yoke (generally).

 

[John Bantin]

Saw a fully rigged tank take a fall out of a vehicle into a grassy (but vehicle stable) area. It fell directly on the first stage. It bent the yoke (actually may have cracked it), and it was a modern heavy yoke, not one of the vintage skinny yokes. Don't recall if the retainer stem bent too...

As to happening while diving, if something caused that much damage, and where it is situated, I'd likely think the divers head would be removed too... Not much to worry about in terms of air delivery with that happening...

Similarly, I took my own tank with DIN valve on a liveaboard in the days when they were fairly rare and the tank fell off the rack in rough weather, distorting the thread and making it nigh on impossible to unscrew the valve. Moral of the story - look after your tank regardless of the valve connection. Brass is soft.