Examination of "mCCR is safer" myth

Gilles · 1st February 2007, 22:28

There are many statements of better mCCR statistics. I have no idea how true this is. The few buddies I have in my part of the world are mCCR'rs and I am continuously reminded to watch out for my eCCR death machine.

ASSUMING these statements are true, what truth can be extracted from these statistics? and what could be done to improve eCCR as a result.

***ScubaDadMiami*** · 1st February 2007, 22:56

Run a search, and you will see that this is already a discussion that is ongoing. In any event, I fly my unit with a lower set point, manually maintaining at the desired level.

People will say: "So what's the purpose of getting the eCCR in the first place?" Well, I will give you a real world example of where using an eCCR this way is good.

Last weekend, while doing a Florida S.C.R.U.B. dive, the seas were high, and we were getting thrown around on the boat. I stepped onto the back platform, ready to hit the water, but the captain had to pull the boat up to the shot line for me to make my jump. One slip, and I would have been thrown into the water at the wrong time. It required holding on with two hands.

I had already added a good shot of oxygen as I approached the platform. However, in the strong wind, the boat was pushed away from the line very quickly, and it took a bit for the captain to get us to the jump point after my buddy and I were aft, set and ready to go. So, my oxygen level started to drop. Again, I observed this and was aware that it was happening.

I decided to allow the computer to fire instead of risking falling into the water by removing a hand to hit the manual add. I entered the water without incident, and I resumed flying above the back up set point for the rest of the dive.

I find that having this type of convenience is a good reason to have an eCCR. Of course, having a backup to the engaged mind, just in case a distraction occurs, is another good reason to have an eCCR. So, there is something to having eCCR even if you elect to fly manually most of the time.

I think that mCCR keeps the mind focused, and there is something to this. However, that does not mean that there is not room for eCCR or flying an eCCR manually. So, I voted for "some other reason."

bgpartri · 1st February 2007, 22:57

I think this is a fascinating subject.

As an alternative to analyzing deaths, why not analyze success?

I think that one of the reasons that mCCRs have a better record is that the divers have a better mental image of what's happening in their rebreather. For example, they know that when they vent or the adv fires, they need to check their ppo2.

The knowledge that you have to check is another.

The habit that usually when you check you do something makes it psycologically more satisfying.

What about some of the other successes? Why are there so few MK 1x deaths. Military training? Checklists?

Why are safe rebreathers safer?

Bruce

**Gill Envy** · 1st February 2007, 23:09

what i'm looking for are some facts to back up the ascertion. i'm inclined to be sympathetic to argument that "flying manually" keeps one more engaged and i'm all for folks articulating that further, but it would be really nice if anyone has some facts to back it up...otherwise it's speculation. Speculation is valuable in the absents of facts, but facts are even better.

there are other factors that could effect the "KISS camp" statistics. I'm very interested if there is anyone who has found a way to isolate these factors and has numbers to point to. For instance, it seems that a BOV is a very common part of the mCCR platform, do we have any way to determine how much a BOV could be influencing the numbers?

bgpartri · 1st February 2007, 23:31

Quote: (Originally Posted by Gill Envy)

..... do we have any way to determine how much a BOV could be influencing the numbers?

That's another good one. There are only two controls on the KISS. BOV or add oxygen. It's hard to get confused about what to do.

***EBT*** · 1st February 2007, 23:50

Guys,

The numbers at the moment are statistically insignificant. Theres certainly not enough robust data to start breaking down individual contributory factors.

My personal opinion/belief is that the majority of the difference will come down to mindset and attitude. Its that that drove the selection of the unit, not the other way around.

You can of course fly an eccr perfectly safely and that doesnt have to mean full manual all the time, it just means having the attitude that you cant trust the unit and to be aware of the nuances of your unit (like how often you should hear the solenoid fire).

So far, mCCR's have a great track record, but dont be fooled into believing its all about the equipment. The kiss is great in as much as the loop is very robust with minimal breaks and the controls are simple/intuitive (reduces confusion), but I know of guys who diligently dive other breather brands safely.

/Z

RAL · 1st February 2007, 23:53

Any machine can & given enough time will fail. The more complex the machine the more things to go wrong & go wrong in more complex subtle ways. This holds true for widgets, cars & life support systems. While many complex machines have advantages over simple machines, being more dependable is not one of them.
Rule #1 know your O2. The manual machine will not tolerate someone who takes that rule lightly, so it is a a bit harder to develope a caviler attitude.
So it comes down to a simpler more reliable machine that will not allow you to become lax. Because you must watch closely you are likely to catch a problem earlier.
That does not mean that the manual is "better" than the E machine. A piper cub is far safer than a Apache attack helicopter but then again it will not be as good a tool for certain jobs.

RAL

Joe · 2nd February 2007, 00:26

They will all kill you. A safe Rebreather is an oxymoron.

My .02....

If you are careless, inattentive, cocky, cavelier or do not fully understand how *your* particular unit functions, odds are it will at least hurt you if not kill you.

Both mCCR and eCCR rely on sensors and the calibration of same. If you calibrate wrong or if you do not understand how your sensors work so you can identify a bad one you will quickly get in trouble with them.

For anyone to say any particular type of CCR is safe or safer is delusional. Fooling oneself into a comfort zone with a denial of reality only compounds the inherent danger.

IMO, the best we can say is that for whatever reason one prefers or is more comfortable with a particular type of unit but they both rely on sensors to track your ppO2 and IMO are equally dangerous.

Russ · 2nd February 2007, 00:57

kind of wish my unit had an constant flow orifice...

Tom Rose · 2nd February 2007, 01:08

Hi guys,

Take a look at the questions....as phrased they are intentionally or unintentionally to provoke arguments or at least heated discussions. And IMHO useless.

Properly built, used, and cared for leaky valve systems and electronic controlled systems work just fine.

All of them can kill us....

Discussed over and over again on this site is why people die and what machine is safer. Again IMHO that depends upon the person using the machine, the depths of intended use, all those little details that side with the hidden flaw (we the users are the hidden flaw)

This damn sport can be dangerous, mountain climbing can be dangerous, sky diving can dangerous...when you tweak the devils tail, you takes your chances....some of the eggs break.

I do not think that many folks would consider diving to 400 feet with a leaky valve system, but some of them are good in the 0 to 200 foot range. ECCRs can certainly go deeper.

Likewise, just look at the versions of how to dive an eccr in the shallows.

Guys there are just too many variables that are usually unstated to have a valuable discussion.

If I have offended anyone, I'm sorry and I really did not intend to. Its late and I am packing and trying to keep the weight on the boxes as low as possible.

I'm heading diving Saturday for a week with my leaky valve system and diving with some guys with eccrs.

I just hope none of us makes a stupid mistake....if things are really good, I may just send you some pictures from Bonaire. Warm, shallow, clear, tropical water...may even have a rebreather in them.

Safe dibing
Tom

View Poll Results: Assuming myth "mCCR's are safer"; what truth can be extracted?
mCCR should rule the universe (ban eCCR)	3	2.91%
mCCR forces better habits	41	39.81%
constant orifice flow is the deciding factor	3	2.91%
Some combination of 2&3	19	18.45%
Some other reason (please state)	6	5.83%
mCCR is safer myth is a load of cr*p	31	30.10%
Voters: 103. You may not vote on this poll

1st February 2007, 22:28	#1 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 762	Examination of "mCCR is safer" myth There are many statements of better mCCR statistics. I have no idea how true this is. The few buddies I have in my part of the world are mCCR'rs and I am continuously reminded to watch out for my eCCR death machine. ASSUMING these statements are true, what truth can be extracted from these statistics? and what could be done to improve eCCR as a result. __________________ Gilles http://www.dirrebreather.com Last edited by Gilles : 1st February 2007 at 22:33.
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1st February 2007, 22:56	#2 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 2,132	Re: Examination of "mCCR is safer" myth Run a search, and you will see that this is already a discussion that is ongoing. In any event, I fly my unit with a lower set point, manually maintaining at the desired level. People will say: "So what's the purpose of getting the eCCR in the first place?" Well, I will give you a real world example of where using an eCCR this way is good. Last weekend, while doing a Florida S.C.R.U.B. dive, the seas were high, and we were getting thrown around on the boat. I stepped onto the back platform, ready to hit the water, but the captain had to pull the boat up to the shot line for me to make my jump. One slip, and I would have been thrown into the water at the wrong time. It required holding on with two hands. I had already added a good shot of oxygen as I approached the platform. However, in the strong wind, the boat was pushed away from the line very quickly, and it took a bit for the captain to get us to the jump point after my buddy and I were aft, set and ready to go. So, my oxygen level started to drop. Again, I observed this and was aware that it was happening. I decided to allow the computer to fire instead of risking falling into the water by removing a hand to hit the manual add. I entered the water without incident, and I resumed flying above the back up set point for the rest of the dive. I find that having this type of convenience is a good reason to have an eCCR. Of course, having a backup to the engaged mind, just in case a distraction occurs, is another good reason to have an eCCR. So, there is something to having eCCR even if you elect to fly manually most of the time. I think that mCCR keeps the mind focused, and there is something to this. However, that does not mean that there is not room for eCCR or flying an eCCR manually. So, I voted for "some other reason." __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com Last edited by ScubaDadMiami : 1st February 2007 at 23:00.
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1st February 2007, 22:57	#3 (permalink)
bgpartri Rebreather Zealot Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Sport Kiss Classic Kiss Titan Join Date: Apr 2005 Location: Vancouver, Canada Posts: 414	Re: Examination of "mCCR is safer" myth I think this is a fascinating subject. As an alternative to analyzing deaths, why not analyze success? I think that one of the reasons that mCCRs have a better record is that the divers have a better mental image of what's happening in their rebreather. For example, they know that when they vent or the adv fires, they need to check their ppo2. The knowledge that you have to check is another. The habit that usually when you check you do something makes it psycologically more satisfying. What about some of the other successes? Why are there so few MK 1x deaths. Military training? Checklists? Why are safe rebreathers safer? Bruce __________________ http://www.shearwaterresearch.com Good judgment comes from experience. Experience comes from bad judgment.
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1st February 2007, 23:09	#4 (permalink)
Gill Envy Shearwater Copis Divers Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,315	Re: Examination of "mCCR is safer" myth what i'm looking for are some facts to back up the ascertion. i'm inclined to be sympathetic to argument that "flying manually" keeps one more engaged and i'm all for folks articulating that further, but it would be really nice if anyone has some facts to back it up...otherwise it's speculation. Speculation is valuable in the absents of facts, but facts are even better. there are other factors that could effect the "KISS camp" statistics. I'm very interested if there is anyone who has found a way to isolate these factors and has numbers to point to. For instance, it seems that a BOV is a very common part of the mCCR platform, do we have any way to determine how much a BOV could be influencing the numbers? __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
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1st February 2007, 23:31	#5 (permalink)
bgpartri Rebreather Zealot Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Sport Kiss Classic Kiss Titan Join Date: Apr 2005 Location: Vancouver, Canada Posts: 414	Re: Examination of "mCCR is safer" myth Quote: (Originally Posted by Gill Envy) ..... do we have any way to determine how much a BOV could be influencing the numbers? That's another good one. There are only two controls on the KISS. BOV or add oxygen. It's hard to get confused about what to do. __________________ http://www.shearwaterresearch.com Good judgment comes from experience. Experience comes from bad judgment.
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1st February 2007, 23:50	#6 (permalink)
*EBT* Apprentice Luddite Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: UK, Brighton Posts: 1,970	Re: Examination of "mCCR is safer" myth Guys, The numbers at the moment are statistically insignificant. Theres certainly not enough robust data to start breaking down individual contributory factors. My personal opinion/belief is that the majority of the difference will come down to mindset and attitude. Its that that drove the selection of the unit, not the other way around. You can of course fly an eccr perfectly safely and that doesnt have to mean full manual all the time, it just means having the attitude that you cant trust the unit and to be aware of the nuances of your unit (like how often you should hear the solenoid fire). So far, mCCR's have a great track record, but dont be fooled into believing its all about the equipment. The kiss is great in as much as the loop is very robust with minimal breaks and the controls are simple/intuitive (reduces confusion), but I know of guys who diligently dive other breather brands safely. /Z __________________ Eagles May Soar, but weasels don't get sucked into jet engines! Rebreather World Terms of service Real diving t-shirts for real divers
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1st February 2007, 23:53	#7 (permalink)
RAL Longbottom Time Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Jan 2006 Location: North Florida Posts: 390	Re: Examination of "mCCR is safer" myth Any machine can & given enough time will fail. The more complex the machine the more things to go wrong & go wrong in more complex subtle ways. This holds true for widgets, cars & life support systems. While many complex machines have advantages over simple machines, being more dependable is not one of them. Rule #1 know your O2. The manual machine will not tolerate someone who takes that rule lightly, so it is a a bit harder to develope a caviler attitude. So it comes down to a simpler more reliable machine that will not allow you to become lax. Because you must watch closely you are likely to catch a problem earlier. That does not mean that the manual is "better" than the E machine. A piper cub is far safer than a Apache attack helicopter but then again it will not be as good a tool for certain jobs. RAL __________________ The sea does not care about you.
(Online)

2nd February 2007, 00:26	#8 (permalink)
Joe Custom Title Allowed! Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Oct 2005 Location: Florida, USA Posts: 273	Re: Examination of "mCCR is safer" myth They will all kill you. A safe Rebreather is an oxymoron. My .02.... If you are careless, inattentive, cocky, cavelier or do not fully understand how your particular unit functions, odds are it will at least hurt you if not kill you. Both mCCR and eCCR rely on sensors and the calibration of same. If you calibrate wrong or if you do not understand how your sensors work so you can identify a bad one you will quickly get in trouble with them. For anyone to say any particular type of CCR is safe or safer is delusional. Fooling oneself into a comfort zone with a denial of reality only compounds the inherent danger. IMO, the best we can say is that for whatever reason one prefers or is more comfortable with a particular type of unit but they both rely on sensors to track your ppO2 and IMO are equally dangerous.
(Offline)

2nd February 2007, 00:57	#9 (permalink)
Russ New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jul 2006 Posts: 88	Re: Examination of "mCCR is safer" myth kind of wish my unit had an constant flow orifice...
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2nd February 2007, 01:08	#10 (permalink)
Tom Rose Still Learning Current Rebreather/s: Other CCR Home Build Other Rebreather/s: Prism Topaz Other CCR Home Build Join Date: Oct 2005 Location: USA,North Carolina Posts: 328	Re: Examination of "mCCR is safer" myth Hi guys, Take a look at the questions....as phrased they are intentionally or unintentionally to provoke arguments or at least heated discussions. And IMHO useless. Properly built, used, and cared for leaky valve systems and electronic controlled systems work just fine. All of them can kill us.... Discussed over and over again on this site is why people die and what machine is safer. Again IMHO that depends upon the person using the machine, the depths of intended use, all those little details that side with the hidden flaw (we the users are the hidden flaw) This damn sport can be dangerous, mountain climbing can be dangerous, sky diving can dangerous...when you tweak the devils tail, you takes your chances....some of the eggs break. I do not think that many folks would consider diving to 400 feet with a leaky valve system, but some of them are good in the 0 to 200 foot range. ECCRs can certainly go deeper. Likewise, just look at the versions of how to dive an eccr in the shallows. Guys there are just too many variables that are usually unstated to have a valuable discussion. If I have offended anyone, I'm sorry and I really did not intend to. Its late and I am packing and trying to keep the weight on the boxes as low as possible. I'm heading diving Saturday for a week with my leaky valve system and diving with some guys with eccrs. I just hope none of us makes a stupid mistake....if things are really good, I may just send you some pictures from Bonaire. Warm, shallow, clear, tropical water...may even have a rebreather in them. Safe dibing Tom __________________ The 50-50-90 rule: Anytime I have a 50-50 chance of getting something right, there's a 90% probability I'll get it wrong the first time. www.atlimp.com
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