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Post by SeaRat on Dec 5, 2005 22:18:46 GMT -8
In other threads, there has been a lot of discussion about the need to possibly "drink the water" in order to initiate flow in a flooded double hose regulator. This, I found, came from an entry in Cousteau's The Silent World, where Cousteau describes the very early training that Frederic Dumas gave to divers:
I was not convinced that swallowing the water was necessary, even for a flooded double hose regulator. So last weekend, when I did the work on the scoop fin, I also did several ditch and dons of my twin fifties with my DA Aquamaster regulator attached. The DA Aquamaster did not have a non-return in the mouthpiece's inhalation side.
I first took the rig off over my head in standard fashon, and set it on the bottom. I then removed the mouthpiece, and placed it under the regulator, tucked down so it would not loose its air in the hose, and did my ascent. I got a breath, and went back down, and as normal, allowed the mouthpiece to free flow, then got it back in my mouth without problems.
I then took it out again, and turned off the air, and allowed it to hang vertically and bubble, showing that it was flooding. I surfaced exhaling as normal in a free ascent, got a few breaths on the surface, and went back down. I expected to have a harder time establishing flow than the last time. I turned on the air, and immediately the regulator initiated a free flow, clearing itself of the flood. I then simple put the mouthpiece in my mouth, and began the donning process (again over my head).
This has led me to believe that the need to "swallow a cupful of water" to initiate flow is no longer applicable. Perhaps with the notoriously hard-breathing DA Aqualung, that was a problem. But with more recent regulators (Aquamaster, Royal Aquamaster, Trieste, Mistral, Hydro Twin, etc.), I don't think this is needed.
John
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Post by duckbill on Dec 5, 2005 22:59:23 GMT -8
O.K. Now I'm perplexed.
Good test, but something doesn't add up as far as the freeflow situation.
If the regulator's demand chamber was truly flooded, with ambient pressure equal on both sides of the 2nd stage diaphragm, why would it freeflow? In that case, it should freeflow every time you turn on your tank's valve, even in air.
Maybe try SLOWLY flooding the hose so it floods without freeflowing and having to shut the air supply off and on?
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Post by Captain on Dec 6, 2005 7:12:52 GMT -8
In years past I had read of a method to clear a completely flooded regulator by using both hands to alternatly squeeze the inhalation hose to produce a pumping action that produced enough delta P to start a free flow. This was before the use of the mouthpiece valves.
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Post by SeaRat on Dec 6, 2005 10:06:50 GMT -8
I have been thinking about my test. First, last evening I took my mouthpiece apart to ensure that I was right, and there was no non-return in the intake hose--that was correct, there was no non-return valve there.
I was startled by the immediate flow of air when I turned on the regulator after flooding it. I let the rogulator sit on the pool's bottom for almost a minute. It was regulator-up, meaning that the bottom box (exhalation side) was toward the surface. The hoses were still buoyant, and above the regulator. That would mean thet the mouthpiece was pointed down, toward the regulator. It is therefore possible that there was some air still caught in the mouthpiece.
When I turned on the regulator, there is a quick pressurization of the second stage, which does affect the lever position. This change in lever position, and the possibility that the air pressure in the mouthpiece would cause the regulator to sense the pressure differential between the mouthpiece and the diaphragm (which was at least a foot below), could have initiated the free flow that I experienced. Water is incompressible, so any change would be reflected right onto the diaphragm, and help initiate the free flow.
One other thing that could affect this free flowing is that my regulators are set for an inhalation suction effort of about 1/2 to 3/4 of an inch of water. It doesn't take much at that suction pressure to initiate a free flow. My tests some years ago of the DA Aqualung (which was what Cousteau was using in the late 1940s and early 1950s) showed an inhalation pressure of at least 3 inches of water, without any venturi action; without significant, ongoing suction, there was no air flowing in the old DA Aqualung regulator. Modern regulators (1960s and beyond) have a very good venturi action.
I will continue these tests this winter, and keep posting here. I'll use several different regulators too, as I have those mentioned above to work with, plus a Snark III, Aqualung Overpressure Breathing, and AMF Voit 50 Fathom. By the end of the winter, we should have some excellent data.
Now, a lot of you reading this have double hose regulator too. I would encourage you to do the same test, and purposely try flooding the regulator in shallow water. I don't encourage anyone not familiar with a doff and don to attempt it without training (I don't think it is now in current courses). Doff and don exercises were easier when the scuba was all that was on the tanks (no BC). But that doesn't prevent someone from putting on one scuba set and taking another into the water to test this concept with their regulators.
My overall impression before these tests, and confirmed at least to some degree by my pool tests last Sunday, are that flooding a modern double hose regulator is not the crisis that some think. Further tests will help prove (or disprove) this thought.
John
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Post by nemrod on Dec 6, 2005 11:28:42 GMT -8
Ihave not dived without the mushroom valves but years ago with my Mistral a roten valve fell off into the hose. Yes it was noticeable because the regulator did not breath right when the valve fluttered up momentarily. But, playing around I did get the thing to fully flood. We were diving in a spring near Vortex that had a cave you could swim through breatholding and we were removing our tanks, swimming trhoug and getting another breath and so on--just cuz---the cave was pelnty big to go through with tanks on--lol. Anyways, I had no problem getting the regulator to clear---preventing free flow was more the problem.
My RAMs are tuned for very low effort, they freeflow almost to easy, with good valves havingto drink water sounds like an urban legend to me.
I don't think pumping a hose would work unless there is a valve on the output side and or you covered the mouthpiece opening with your fingers before pumping or squeezing it. Not having that much experience aside from my Mistral until recently I wonder if anyone here has ever actually totally flooded a regulator by accident and could not re-establish flow with out resorting to drinking water or other odd antics?
James
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Post by duckbill on Dec 6, 2005 13:51:10 GMT -8
I did get the thing to fully flood. I had no problem getting the regulator to clear---preventing free flow was more the problem. You didn't mention HOW you were able to clear the hose and regulator. If you mean that it continued to freeflow, then it was not flooded. Flooding the regulator means no air, freeflowing or not, in the regulator box and hoses. I don't think pumping a hose would work unless there is a valve on the output side and or you covered the mouthpiece opening with your fingers before pumping or squeezing it. James The suggested method of which I am aware is to plug the mouthpiece opening with your tongue while milking the hose (sqeezing/compressing, then rapidly releasing and stretching). You are correct about one-ways. With them installed it is very unlikely to flood a reg, even with a leaky hose, but I think this experiment is considering a worst case, non-return valve scenario. Even with one-way valves installed, a badly leaking or separated inhale hose, and no immediate way or time to make a emergency controlled ascent, you would likely be gagging on an air/water mix. In this case I would seriously consider doffing the tank, cutting the hose back past the leakage, and somehow re-establishing an air flow if the reg is flooded. Of course, having the presence of mind to do so in such a situation is a-whole-nother story. But that is why practice and training is SO important (not that I would suggest cutting hoses while practicing! I would try just not using a mouthpiece. Simply leave the inhale hose dangling and attached to the regulator, flood the works, turn on the air and see what it takes to begin a purge), and also why it is beyond me why underwater doffing and donning procedures would be pulled from basic training. Is that really the case!? Thanks for researching this, SeaRat. I am looking forward to hearing the continuing results of your experiments, as usual. If I can get pool access this Winter I'll try things on my own just for fun. The river is all silty from the recent rains. Oh well! |
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Post by nemrodalt on Dec 7, 2005 1:53:23 GMT -8
"You didn't mention HOW you were able to clear the hose and regulator. If you mean that it continued to freeflow, then it was not flooded. Flooding the regulator means no air, freeflowing or not, in the regulator box and hoses."
Oh heck Duckbill, I don't remember, I just know it was full of water. It was in about 1972 which to figure for you was like 33 years ago! Maybe I should go to the pool and reinact the conditions. Who was it that pulled the stems off of several valves? Please send them to me so I can stick one down in my Mistral intake hose to simulate the rotten and detached intake valve. LOL.
Nemrod
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Post by duckbill on Dec 7, 2005 9:46:51 GMT -8
I wasn't trying to be abrasive. I seriously was curious how you purged the reg. I wish you could remember, but that's perfectly fine. I have yet to pull a stem off a mushroom valve, but when I do (notice: "when", not "if"!) you are welcome to it  |
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Post by nemrod on Dec 7, 2005 11:05:06 GMT -8
"I wasn't trying to be abrasive. I seriously was curious how you purged the reg. I wish you could remember, but that's perfectly fine."
It was not you, it was me---sorry---I get testy sometimes---lol!!!
Best I can remember we were laying the rig on the bottom. If I pushed the mouthpiece down since it wanted to float up and free flow--if I did it slowly--pushing it down it would stop bubbling and flood. Maybe it was not really flooded all the way---since what we were really doing was having fun swimming trhough the cave it was not really a concern. Upon returning to the rig, grabbing it and shaking the tank with the boot on the bottom, grabbing the tank by the back pack and Mistral--shake it a few times and it would go into free flow. I think that is the trip that the original yellow hoses also when kaput and was towards the end of the Mistral era until discovery you guys--lol.
I have not pulled a stem off yet either--I figure that will happen on my last set of silicone valves!
Really, has anyone ever had a regulator totally flood and not be able to restart it or clear it? for what ever reason?
James
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Post by Chirs on Dec 8, 2005 20:24:11 GMT -8
Hi everyone;
Never thought I would find a place like this. I just found my old aquamunster that I stashed about 15 years ago. Thought I would use this new fangled technology and see if I could find some rubber spares.
Wow! Had no idea.... Geat place!
Okay so I'll bight. What do you mean by completely flooded?
1) both hoses full of water?
2) water on both sides of the diaphragm?
I bought mine used for $15 bucks in 1967... I think. Yellow hoses and all. No, I'm not that old just a very early bloomer. Dove it hard until 1989 and put it away. Could not find any rubber parts after a while. When I was in southern Oregon a guy in Phoenix,OR had an old school shop. Reese Dive Shop I think it was. He was my soul source for that old stuff.
Never had a problem purging either hose when flooded fully, upside down/inverted, or on 25 degree days when every single hose around froze up and free flowed. Really did not make a diffrence. Just purge and breath.
And swallowing? Whats that all about? I had a girlfriend that would...... but I certainly wouldn't Uckkkk!
So are you saying if water gets behind the diaphragm the whole breathing thing stalls out? Never had it happen to me and its been through the wringer. Just had to purg it if I wanted air. Am I missing somthing?
Chris
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Post by SeaRat on Dec 18, 2005 16:24:37 GMT -8
I was in the pool again today. I wanted to check the flooded regulator concept again. I used my DA Aquamaster (the one with no non-return valve in the intake mouthpiece) at first, then a Mistral (again, no non-return in the intake side of the mouthpiece), and finally a DX (which has no non-returns on either side, and air comes out of a small tube with three holes in it in the mouthpiece).
I wanted to check out several things that were said above about a leaking intake hose for a double hose regulator, and a flooded regulator. Concerning the flooded regulator, I had to turn off the air to the regulator to get it flooded (as determined by my last tests). This is not what really happens in open water, as almost nobody would consciously turn off the air supply to the regulator to ensure that the regulator was fully flooded.
Leaking intake hose[/B]
First, the leaking regulator. I did something I have never done before, as it is not safe and I do not recommend this for anyone else to try. I went into the water without the clamps on my intake hose either at the regulator or mouthpiece. This was so that I could simulate various malfunctions, first for a leaking hose, then for a flooded hose.
I first doffed my scuba (I was using my twin 42s, with a Sherwood Blizzard as a backup, which I didn't need it turned out). I held the unit in front of me, and worked the intake hose until it was nearly off the regulator, and I put about a 1/8 inch opening at the regulator. It simply bubbled, and did nothing to allow water into the hose. I felt no water in the air I was breathing, with this hole bubbling at the regulator. It gapped about 1/8 inch wide, and about half an inch long. The verdict: a small hole will have no effect on breathing, but will allow air to be drained from the scuba quicker.
Flooded DA Aquamaster[/B]
I then turned off the air to the regulator after taking a big breath, and pulled the intake hose completely off the regulator. I brought it up, and emptied air out of it, replaced it, and set the scuba down with the hoses up (the exhaling hose still had air in it). After placing the scuba on the bottom of the pool, I made a free ascent to the surface, stayed there a minute, then went back down to the scuba. I turned on the air, and no flow occurred. I initiated flow by pulling on the hose several times (three or four).
I repeated the above procedure, but before surfacing I ensured that the exhaling hose was completely flooded too. Both hoses now were on the bottom, rather than floating above the regulator. I surfaced, relaxed a bit, then dived to the scuba. I initiated flow this time by placing my fingers over the mouthpiece and shaking the mouthpiece up and down. On all these attempts, the mouthpiece was well above the regulator in the water column. Again, I had no problems with water in the air (there was none).
DA Aquamaster with a cut hose[/B]
At this point, I had one other test of the DA Aquamaster. As I mentioned above, I had no clamps on the intake hose. So once I had donned the unit after the last test, I pulled off the intake hose at the mouthpiece (and spit out the mouthpiece). The end of the hose continued bubbling, and I had no problems at all breathing off it. I experimented with different positions, and found that as long as it was above the regulator, there was no problem with water coming out. But when below, water tended to intrude into the hose, but it was still breathable. So I took a big breath, then worked for almost a minute (took another breath off the hose too) before getting that hose onto the mouthpiece. It was a tight fit, and the hose was a very nice after market hose I bought about 20 years ago from New England Divers, and I think it's made of vinyl rather than rubber or neoprene. So the fit was tight getting it back on the mouthpiece. I also had a water-tight seal on this hose on the regulator side without a clamp.
Flooded Mistral[/B]
I surfaced and put the Mistral onto the scuba. I jumped back into the water, retrieved my fins from the bottom (where I left them when I came up the ladder), and swam out to the middle of the pool. It's 12 feet deep here, as this is under the platform diving area. I doffed the Mistral-equipped scuba, and made sure that the Mistral was completely flooded. I turned it so that air from the exhaust hose also came out of the hose. The hoses were horizontal on the bottom. When I surface dived to the scuba, and turned on the air. It "took a shake to get flow. No water..." I wrote on my slate. I did get some air leaking, which was positional and due to the small duckbill exhaust in the regulator, which was above the center of the regulator. I then surfaced again, and changed regulators.
Flooded DX Overpressure Breathing regulator[/B]
I changed to the DX Overpressure Breathing regulator, USD's first single stage regulator. It has a hose-within-a-hose concept, where venturi air is sent directly to the mouthpiece. The mouthpiece is made of metal, with the tube inside which receives the venturi air, then pushes it out three small holes directly into the diver's mouth. When I turned on the air (the hoses were completely flooded), the regulator "initiated flow almost immediately. More water in lines and air," I wrote. I found that this needed the complete exhaling roll (roll over the left shoulder) to move water into the exhaust line, then exhale it from the regulator through the duckbill exhaust valve. I also lowered the scuba unit so the regulator was right between my shouldber blades, very low on the upper back, and got the most of the regulator's performance through positioning.
Conclusions[/B]
1. A small hole in an intake hose is no problem at all. A medium sized hole will bubble pretty well, but little water will be introduced into the breathing air. Some air supply will be lost due to the bubbling, however. There is no need to "cut a hose" if there is a small hole in it, as this won't be noticed except by your buddy when he/she sees bubbling from the hose.
2. Breathing from a cut hose, or one that has come loose, is easily accomplished. It is best to keep the hose end above the regulator to get flow from the water pressure differential.
3. A flooded double hose regulator, completely flooded, is easy to clear. Initiating flow takes little more than either shaking the mouthpiece, or pulling on the hose. Once some bubbles start, free flow is initiated by the regulator automatically.
4. Water is purged by the free flow, or stays in the bottom of the regulator, and is no factor at all in the breathing. After clearing the completely flooded regulator, there was no water in the incoming air. If there was any in the bottom of the regulator, it must be falling out of the air during the trip up the hose, and staying in the lower convolutions of the intake hose. But none got to the mouthpiece.
5. The regulator is a DX Overpressure Regulator, because of the unique mouthpiece/venturi hose situaton, will initially have a mixture of air and water. Water will have gotten into the small venturi tube, become an aerosol with the air is it posses through the three small holes, and be bothersome. By letting it free flow a bit longer before putting the mouthpiece into your mouth, the air will be removed and the regulator functions normally. You will have to clear the remainder of the water from the exhaust hose though.
6. If there are no non-return valves in the mouthpiece, then the full roll will be needed to clear the whole breathing tube system (roll to the left when the exhalation hose is the left hose).
My regulators, with the exception of the DX Overpressure Breathing Regulator, had a non-return in the exhalation side of the mouthpiece. If there had been one on the inhalation side, it would have been harder to flood the regulators for this test. Also, other tests from years past, and personal experience, shows that the inhalation side non-return valve provides a barrier to the venturi action of the regulator, and impares flow to a small extent.
I hope this little write-up will help those who have thought about a flooded regulator with dread--there is no need for that. Again, I don't recommend anyone try repeating these tests, unless you are very, very comfortable in the water. I used my twin 42s, with the Sherwood manifold and a backup Sherwood Magnum Blizzard regulator on the other post, which I did not need to use.
Well, it's been a blustery day today, with winds gusting above 40 mph, and then sleet and now snow. I'm awaiting my wife returning from work, so I'll close now.
John
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Post by seakrakken on Dec 18, 2005 19:03:19 GMT -8
Great work SeaRat. This only goes to show how overblown all those seahunt episodes were.  I appreciate the reality check on DH regs and flooding and how easy it is to clear them. For those of us that didn't have the pleasure of being around for when DHs were the rule instead of the exception, this is great need to know info for practice before the need arises in the field. It is also confirmation on how well designed our DH regs really are. |
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Post by duckbill on Dec 19, 2005 0:20:30 GMT -8
Thankyou, John, for experimenting on our behalf. I have been eagerly awaiting your results, as I have been fighting a cold and have been unable to get any pool time in lately. Next is holiday traveling, and maybe next month I will do some clearing drills as you did. One thing I'd like to try is seeing just how dificult it is to flood a regulator when the mouthpiece is off the intake hose, then try clearing it without the mouthpiece replaced. Maybe a hand over the open end of the hose and a quick tug might be all it takes. Drinking public pool water doesn't sound good to me with all that sluffed skin, mucus, phlegm, urine, sweat and chlorine. Can't wait! I'm sure that many unspoken viewers of your thread are also benefiting from your hard work. Thanks again!
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Post by SeaRat on Dec 19, 2005 11:37:09 GMT -8
Duckbill,
Flooding the double hose regulator is easier when the mouthpiece is off the hose, but you still have to turn off the air. This is not something that would normally happen during a dive. If you did, it is apparent to me that it would be easy to initiate flow from a flooded regulator by simply putting your fingers over the opening, and either moving it around or pumping it a bit (as you indicated above). I still see no reason to ever drink the water to initiate flow of post 1960s double hose regulators (at least the ones I have, which are USD regulators, Voit regulators, the Sportsways Hydro-Twin and the Nemrod Snark III).
John
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Post by duckbill on Dec 19, 2005 12:11:16 GMT -8
Hi John,
Maybe when I read somewhere about drinking the water to initiate an airflow, it was offering an alternate method, not necessarily a necessity. I wish I could remember where I found that tidbit. I think it may have been Cousteau's article to which you made reference. Anyway, I'm glad to hear drinking isn't necessary- yuk! I still want to try flooding and clearing my DAAM when I get a chance since I suspect your regulator may be more sensitive than mine. Besides, it's good practice. I regularly practice clearing procedures, but nothing as extreme as a disconnected hose.
Thanks again, and happy 60th.
Stay wet this Winter!
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I appreciate the reality check on DH regs and flooding and how easy it is to clear them. For those of us that didn't have the pleasure of being around for when DHs were the rule instead of the exception, this is great need to know info for practice before the need arises in the field. It is also confirmation on how well designed our DH regs really are.