Regulator bungie for recreational diver

[TSandM]

Exactly! Which is why we put up with those complex systems, with all their failure points -- they have rescue modes for the vast majority of the failures they can have.

My point was simply to say that the argument that adding failure points reduces the probability of a failure is mathematically invalid. Adding failure points may increase the robustness of a system, though, depending on design.

Adding a 90 degree adapter doesn't add any redundancy or any salvage capability, but does add an infinitesimal amount of increased likelihood of a problem. Bottom line: If you put a 90 degree adapter on your reg, YOU ARE GOING TO DIE!

Happy Thanksgiving, everybody!

 

[SangP]

Sigh.

Two DOES increase the chance of failure. 1/2x1/2=.25, this is correct. What's the balance of that equation? (Hint: It's .75)

Falling back on the toss of the coin model from earlier in this very thread, there are 4 possible outcomes from tossing two coins. HH, HT, TH, TT. If 'H' represents failure, 3/4 (.75, or 75%) of them include a failure (H). 25% do not include a failure (TT). 25% is less than 50%, 75% is more than 50%. Adding a second coin increases your chances of a coin landing on heads, in this case, by 25% (from 50% up to 75%).

You're simply not paying attention to the variables, just the numbers. Gotta watch both. Adding more gear increases your chances of something breaking/failing. I've done more than a handful of dives where there were about 30 (thirty) regulators within the team, not counting the setup guys. 30. You're nuts if you think that having thirty regs decreases the chances of ONE of them failing.

And I think something has been lost in translation over the interwebs regarding the swivels. You mentioned something regarding confusing redundancy with failure points. I am not at all confused on the two. Redundancy gives you options when something fails at the expense of added chance of someTHING failing. I can get down with that. Swivels don't add much to most people's diving kit, yet increase orings and moving parts. I don't get down with that.

In my world I drive in a car with 4 tires I'm sure in your world your car only has one tire cus there no way 1 wheel failing will be less then all 4 wheels failing.

Either you live in a singularity or as you said earlier you got a handle on redundancy...

 

[PfcAJ]

Sense. You're not making any.

 

[SangP]

Sense. You're not making any.

I'm so hoping you are not a safety officer cus according to your theory, more redundancies means more failures so, there is no need for any spares.

Suffice to say I completely disagree with your theory that adding redundancies increases the chances of failures cus you've seem to completely miss the boat about risk analysis.

 

[Hepcat62]

I'm so hoping you are not a safety officer cus according to your theory, more redundancies means more failures so, there is no need for any spares.

Suffice to say I completely disagree with your theory that adding redundancies increases the chances of failures cus you've seem to completely miss the boat about risk analysis.

Alternatively, you're wrong.

To use your tire analogy (with slightly simplified math), for every tire I add to my vehicle I increase the chance of a single tire blowing out. For a four tire passenger car, I have 4 * Pr(blowout). A commercial truck with, say, 4 sets of 2 tires each has 8 * Pr(blowout) chances of experiencing a blowout - double the chances. Adding redundancy has increased the chances of a single failure occurring. What's important is that the added redundancy has significantly reduced the odds of having an immediately catastrophic failure. In the passenger car, a single tire failure results in an undrivable vehicle. In the shipping truck, a single tire failure will never fully disable the truck. Provided that no one tire group is completely wiped out, the truck can potentially sustain up to four individual tire failures before it is completely incapacitated.

 

[PfcAJ]

Again, sigh.

That's NOT my 'theory'. Don't try and put words in my mouth. I never said there is no reason for spares, backups, or redundancy. But having a bunch of scuba stuff laying around increases the chance that SOMETHING is broken. Math.

If you have two regs you are more likely to see one of them fail than having just one. Because you have two. This is evidenced by math. If you have 50, you're more likely to have one of them fail than if you have just 2. Once again, math.

Deciding on if you need a redundant system is determined by the result of having a single failure. A double failure is less likely than a single failure. Math, again.

If you disagree with math, I can't help you.

 

[waterpirate]

I had a swivel on my first stage, I took it off when I purchased a better suited first stage for my hose routing scheme. Easy peasy.

How about this?
all gear needs to be properly maintained in working order.
Less gear to maintain that is essential, is better than maintaining alot of un needed bits

If you strip away the ego and hubris it comes down to the failure of any system comes down to maintanace or human error. Human error is overcome through familiarity and practice add nauseam with said gear. Maintanace of the gear is best addressed through the " less is more" mind set.

The other key componant of any system is the collective workings of the bits of said system. The system bits are related to some other bits if not all the bits. So 14 pages later we learned that bungieing an octo without a long primary is a bad thing, not a good thing. I would add also that just looking like a squared away diver does not imply or confirm that said diver put in the time to become familiar with the gear, thus a complete breakdown of the system based on human error.

That is the non denominational explanation.

p.s. is there a rule of thumb or RD version of all that math?
Eric

 

[markmud]

I had a swivel on my first stage, I took it off when I purchased a better suited first stage for my hose routing scheme. Easy peasy.

How about this?
all gear needs to be properly maintained in working order.
Less gear to maintain that is essential, is better than maintaining alot of un needed bits

If you strip away the ego and hubris it comes down to the failure of any system comes down to maintanace or human error. Human error is overcome through familiarity and practice add nauseam with said gear. Maintanace of the gear is best addressed through the " less is more" mind set.

The other key componant of any system is the collective workings of the bits of said system. The system bits are related to some other bits if not all the bits. So 14 pages later we learned that bungieing an octo without a long primary is a bad thing, not a good thing. I would add also that just looking like a squared away diver does not imply or confirm that said diver put in the time to become familiar with the gear, thus a complete breakdown of the system based on human error.

That is the non denominational explanation.

p.s. is there a rule of thumb or RD version of all that math?
Eric

Hey Eric,

I had a first stage that was factory defective. It was overhauled and given a "clean-bill-of-health" twice in 3 months. It was still defective and the casting flaw was propagating creating a biggger problem everytime I dived. No maintenance issue here.

Sh!t happens. If you want to survive on the ocean, you should have some truly redundant systems.

markm

 

[danvolker]

I had a US divers Conshelf once, a diaphram regulator.....it let go on a 140 foot dive on the Hole in the Wall, while I was spearfishing and not near anyone looking in my direction, meaning a direct free ascent was my only option ( this was in my pre-DIR days around 1992).... The Diaphram design could be said to be inherently more likely to fail than a piston design...and in fact, I have a scubapro mark 2 with an R 190 2nd from around 1992, that works exactly as well today as in 1992, and I do not recall if it has ever even been serviced, beyond getting DIR length hoses put on it.... Different gear will have different liklihoods of failure.

I had a Pontiac Fiero back in the early 80's..it was very prone to electrical failures.... Today I am driving a Ford Raptor....most likely it will go many hundreds of thousands of miles with zero failures.
Some gear is overbuilt, and simple where it counts. Other gear is underbuilt, and has many failure points within it.


For a diver that makes the right gear choices, failure of gear is really not likely. And the chance that your buddy would have a failure of the same type as yourself, at the same time, is retarded to even discuss( unless we are talking an Ice dive and the common failure was a freeze up...and we are NOT talking about this

Failure of a single diver to check on their air pressure, and to then run OOA, is the kind of a failure far more common in diving.

 

[divad]

For a diver that makes the right gear choices, failure of gear is really not likely. And the chance that your buddy would have a failure of the same type as yourself, at the same time, is retarded to even discuss( unless we are talking an Ice dive and the common failure was a freeze up...and we are NOT talking about this

If you're referring to a specific incidence, where could I go to read a discussion of that?