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Originally Posted by Jax
How often has /does a regulator actually fail?
Not talking about an out of air situation.
I'm talking a situation where you have plenty of air in your tank and you simply can not breathe off your reg.
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That's exactly what you get with a clogged tank valve.
I think for recreational diving an H valve with 2 firsts and two seconds is adequate redundancy. I sometimes carry a pony of air as well but that is more to hand off to someone needing it. Most of my diving these days is with manifolded twins, which of course offer full redundancy.
No, actually you are not. Simply do a controlled emergency swimming ascent (CESA) to the surface. You still have a lot of air in your lungs (remember Boyle's Law?). This is assuming you are not in an overhead environment, or have a decompression obligation. But that's very advanced diving, and we used to consider that out of the sport diving realm. More gear causes more drag, and gives a sometime false sense of security. We used to teach self-sufficiency through diving skills, rather than dependency on equipment for our safety. This is actually an important concept, because if you say, "...you are really out of air..." you are telling people that they have no alternatives, and that false statement can cause panic.
This can be considered a "failure," but it really is a characteristic of just about all single hose regulators. Dacor used to coat their second stage lever and spring with Teflon to keep ice from adhering to the parts. Dacor also produced the Dial-a-Breath double hose regulator, which was tested to -50 degrees F and under Antarctic ice without failure, and later the R-4 double hose regulator. None of these could be considered "modern" as they had no LP ports and no HP port for an SPG. Dacor led the way in under-ice diving, probably because they were located in the Chicago, Illinois area.
Burhan,
Dive Plan
I want to dive three regulators. The first is my Healthways SCUBA Hybrid, without a duckbill in the exhaust. This has the original Healthways SCUBA case with the innards of a Gold Label, and I have Voit grey hoses on it with a curved mouthpiece right now. I want to find out just how important the duckbill is to the exhalation characteristics. Second, I want to check out my Scubapro Mark VII with the AIR-1 second stage and see whether the added O-ring and new O-ring on the oscillator make a difference. Third, I want to dive my Healthways ScubaAir 300 sonic reserve for the remainder of the dive.
Observations
The Healthways SCUBA hybrid definitely leaked a bit of water into the exhaust hose when I was head-down, which was a lot in the current and being slightly positively buoyant at the shallow depth. When I was horizontal or head-up, it breathed great on the exhalation. Being head-down was not a huge problem, but was noticeable for higher exhalation resistance.
The Scubapro Mark VII did honk initially when I took a breath or two when I was putting the regulator on, but thereafter, it did not. That was even when I got down to noticeable low pressure too. So it still has problems. I think I'll try Bob's advice and put the 109 second stage back on and try it on land. I was diving my twin52s, and started out with 1000 psig in them. I used the SCUBA hybrid using both cylinders, with the reserve up on each one (I am diving a cross-over manifold with J-valves on the tanks). For this dive, I dove only one cylinder "On" with the reserve up.
The Healthways ScubAir 300 performed well, though it is a wet breather when head-down. I used both cylinders with the J-reserve down for the rest of the dive. The reserve came on and the sonic was unmistakable. So I have a good impression of the ScubaAir 300 sonic reserve. When I went on reserve, I surfaced shortly thereafter and swam to the exit using my helmet-tied snorkel. When I tested the tanks, there was about 300 psig left.
Other observations: I watched a crawdad with a lot of worms on its claws, and a couple elsewhere on its body. I read a paper where these little worms are commensal most of the times, when food is abundant, but when the food is taken away they go for the crawdad's gills and become parasitic on the crawdad, but I'm not sure its the same worms I'm observing.
I found another golf ball, and a pair of sunglasses which look new that my wife can use for her bicycling (if I can get her on the bike again). Kids forget to take off their glasses when they jump from High Rocks (about 20 feet) into the Clackamas River. I also saw one tennis shoe, but decided to leave it there.
Special Problems and Ideas
The tank harness is harder to get out of and back into when on a sliding bank of rocks! At one point, I put my arm through the shoulder strap with a twist in the strap, and for a moment thought I might need help getting back out. But after some struggle, was able to make it.
I took my tanks and weight belt down first, then got into my wet suit and took the rest of the gear down. That made for an easier time entering.
I exited at a small park, and there were two women with four small kids playing in the water--all the kids were in life jackets! I got some interesting looks from the kids when I swam in too. I complimented them on that decision, and told the two women about having my kids, when the tubed the river even as swim team members, in life jackets. We've had six drownings locally in the last two or so weeks; this is very, very important even for adults. We had one adult enter the water from a dock when the lake was fairly cold (55 or so degrees F) without a lifejacket to retrieve a hat. He was seen struggling, then went under and was recovered by dive rescue teams the next day. Here's a newspaper ad I took out in 1997 in The News-Review, our Roseburg, Oregon local paper (RHS is Roseburg High School; gosh, that was 17 years ago--time really flies when we're enjoying the diving):
This is a Nikonos II photo, 35 mm lens, probably at 125th second at F-8 or so. Photo by me. Note that this is not copyrighted; if any of you want to use it anywhere, please feel free do to so.
