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Post by technidiver on Feb 18, 2019 16:24:33 GMT -8
I've read in numerous places that a DH won't work on triples, and yes it sounds somewhat logical. But a DH will work on triples with a far sided port, and should also work on a manifold with an isolator bar. Here's the proof. It may not look aesthetic and some people prefer the DH being centered, but to each their own. www.flashbackscuba.com/museum/Cousteau%20Experience/CousteauFrameset-1.htmTD
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Post by technidiver on Feb 18, 2019 16:25:41 GMT -8
Link doesn't work (I expected this to happen) I'll get a working one up.
TD
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Post by technidiver on Feb 18, 2019 16:30:25 GMT -8
TD
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Post by nikeajax on Feb 18, 2019 16:50:58 GMT -8
What the... who the... HUH? Not that I really pay attention to such things but, who the (expletive deleted) told you this? Unless I'm missing something completely, an air reservoir, is an air reservoir, is an air reservoir!
An' yeah, if Albert Falco kin do it, by gum, it's doable! Probably THE BEST diver ever to set foot on the deck of the Calypso, an that includes JYC too: he didn't put up with shenanigans!
JB
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Post by vance on Feb 18, 2019 16:52:10 GMT -8
Why not? Unequal hose length? This is also a bit of a problem with a Y valve, but it really doesn't make a difference. You can also use different length hoses, which aren't that hard to find.
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Post by nikeajax on Feb 18, 2019 16:56:33 GMT -8
TD, many, many, many of the earliest set up were triples, do to their low capacity, I believe 1800-psig, so they needed to couple them all together to get a decent dive time.
JB
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Post by technidiver on Feb 18, 2019 17:04:35 GMT -8
What the... who the... HUH? Not that I really pay attention to such things but, who the (expletive deleted) told you this? Unless I'm missing something completely, an air reservoir, is an air reservoir, is an air reservoir! An' yeah, if Albert Falco kin do it, by gum, it's doable! Probably THE BEST diver ever to set foot on the deck of the Calypso, an that includes JYC too: he didn't put up with shenanigans! JB I've read before that using triples with an off c entered post wasn't "safe" "comfortable" or "proper". Some people are more concerned about how they look while diving then getting the dive accomplished! I've just about had enough of this nonsense. TD
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Post by technidiver on Feb 18, 2019 17:06:34 GMT -8
Why not? Unequal hose length? This is also a bit of a problem with a Y valve, but it really doesn't make a difference. You can also use different length hoses, which aren't that hard to find. Couldn't you also use those EDPM stretchy hoses which would stretch to the shape of how the reg was used? There's many different solutions for this problem. Phil, didn't you have a fix for using two regs (one as a DH) on a Y valve? Something about spacing? TD
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Post by SeaRat on Feb 18, 2019 18:07:27 GMT -8
TD, You are right, the myth is busted! If you look closely at the Cousteau use of the triple tanks with the offset valve, you'll probably see a hose extension on the exhalation hose. That gets around the "hose is too short" problem. JB, you are correct, these have been used since the earliest times. Here's a photo I took at the Cousteau exhibit last fall: I did a set of experiments with this a few years back, using separated, independent doubles. Note that I'm using my Mistral regulator, with hoses that are superflex and on a Healthways Hope-Page mouthpiece. There was no problem with the length of the hoses, but there would have been if I had used either my Mistral or Royal Aquamaster with USD length hoses. So, what are the advantages and disadvantages of the asymetrical placement of the demand regulator? Here are a few: --By being on one side, that side can be tilted down to represent the exact center of the diver's lungs during the dive. If you look at the Cousteau Britanica divers, you can actually see them doing this maneuver at times. --You can use the modern USD triple tank valve. --If you are not careful, you can cause a lot harder breathing by swimming the opposite way, and having the demand valve much higher in the water column than your lungs. Now, about the Cousteau use of these tanks. These were extra-large capacity tanks, used for his filming of dives on the Britannic wreck. They were using a breathing mixture of helium, nitrogen and oxygen in those tanks, which were very, very heavy. Here you can see where they extended the exhalation hose about a foot: You can see the string attached to the hose, which is where the extension was made for the exhalation hose. Note that the divers have three incompressible floats attached to the cylinders; this is because they are so heavy in the water that the floats are needed. Here is the film on the Cousteau Britannic dives: John
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Post by SeaRat on Feb 18, 2019 19:21:16 GMT -8
I have just finished watching this video again, and cannot help being struck with the fact that seeing Calypso sailing is a wonderful sight. I was also struck by the attention to detail that these divers used in their planning. Now, I have one further insight into the Calypso team's use of their Aqualung setup. Because of the offset of the valve, and it being on the left side, they made one further adjustment of their LaSpiro Royal Mistral regulators. If you look closely, you can see the change. Remember I said that they extended their exhaust hose above? Well, that's what they did, but their exhaust hose was on the right side, the long side of the hose loop. Their inhalation hose hose is on the left, not on the right as is normal. How did they do this? They reversed the bottom box in relationship to the top box. This doesn't really look bad because the LaSpiro Royal Mistral has a more symmetric label than does the USD regulators, with their rectangular labels. For these deep dives you want the inhalation hose to be the shorter of the two hoses, so the extension had to be on the exhaust hose. But the location of the valve's regulator post necessitated reversing the two hoses. If you look closely at the shots showing the regulator, you can see the label being upside down, with a sidewise royal crown. Note the sidewise Royal Mistral crown and the reversed hoses, and the exhalation hose going over the diver's right shoulder. For breathing resistance, it doesn't matter much how long the exhalation hose is, only that it returns to the diaphragm of the regulator so that there's no free flow of air. John
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Post by SeaRat on Feb 18, 2019 20:02:58 GMT -8
Now, about the use of the Royal Mistral for dives to 370 feet; they were perfect! Why? Well, Navy EDU tests showed the Mistral as having better performance at depth that the Aquamaster. Somewhere I have these graphs, and will post them here. Once flow is initiated, the Venturi effect on the Mistral is better than the Aquamaster, requiring almost no effort to continue the breathing cycle. Here's the Mistral graph (directly below). Note that the inhalation resistance goes down almost to zero the deeper the diver goes. Ignore the exhalation resistance, as these measurements were taken in the 1950s and the USD exhalation valve was a bit different (harder breathing too). Now, here's the Royal Aquamaster, which many consider the epitome of the Aqualung family of double hose regulators. Note that the axes of the two graphs are switched, and inhalation is on the top rather than on the bottom. And, just for perspective, here's a graph of the Dacor model R-3 Dial-A-Breath regulator against an Aquamaster ("competitive regulator"), and why the U.S. Navy did not approve the R-3 Dial-A-Breath regulator for its use: Both the Mistral and the Aquamaster (and Royal Aquamaster) did got U.S. Navy approval. John
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Post by technidiver on Feb 18, 2019 20:15:03 GMT -8
I'm not going to knock the USD Mistral, as I don't have one, but I do have a Spiro Mistral which is internally the same as the Royal. The Royal had redesigned Cans for better air flow. If the USD Mistral is a good perfomer, then I can't imagine how well a Royal Spiro Mistral would've performed!
The Cousteau divers have also used several different regulators during their years prior to the brittanic, such as the Conshelf VI and RAM and DAAM. Why they wouldn't use a RAM for the expedition on the brittanic.
Well, other than the reliability of the Mistral, I can't see why not!
Also, thank you John for getting those screenshots from the brittanic episode and for posting the graphs.
TD
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Post by technidiver on Feb 18, 2019 20:16:54 GMT -8
A chest mounted DH could also work for doubles, triples, etc. As many tanks as you want! TD
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Post by snark3 on Feb 19, 2019 2:18:16 GMT -8
Mike Nelson used to dive with a two hose and triple tanks. Later today I'll go downstairs and take some pix of my triples with 2 hose regs
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Post by nikeajax on Feb 19, 2019 7:24:03 GMT -8
TD, when I was a wee-lad, The Undersea World of Jacques Cousteau came on as TV specials: they weren't on on a regular basis, and you made absolutely-totally-utterly-completely-sure you didn't have anything to do that night, because you couldn't tape them!
I remember the Britannic episode as being a very big deal: imagine something between the final game of the World Series and the moon landing--it was magical! What I remember most is their squeaky voices from the gas mixture they used. All that week that was all my friends and I would talk about and recreate the adventures during school recesses.
JB
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