Differences between eCCR’s and mCCR’s design that may effect mortality rates

CharlieT · 5th February 2007, 13:36

Quote: (Originally Posted by moley)

You really are a lovely bloke Mike.

That's not his mother says

Charlie

CharlieT · 5th February 2007, 13:47

Quote: (Originally Posted by dave t)

Awhile ago I had a classic inspo lid with just one handset and a kiss valve attached, I used to set the handset to 0.7 and run my po2 at about 1.2 via the kiss valve. it worked very well, po2 was very stable, if I had to be very lax on ascent for some reason the handset would take over, it could even be easily switched to 1.3 for high po2 ascents in an emergency. Battery life was long cos there was hardly any solenoid action, calibration was easy, and more importantly I had the kiss style mindset right!!! sounds good?

Well actually it isnt so good, I got to worry about is the handset going to work when I really need it, when it does will the solenoid stick open due to little use, will the solenoid stick closed and I wont notice until its too late.

At least on a kiss unit there is no distraction of "will my parachute open"

on a ECCR the electronics are working (and verifing) all the time

In my opinion both systems are very good in the right hands but keep them seperate!!

just my opinion

Dave

The voice of common sense and reason again!

The Vision manual says you should regard your handset as your primary monitor and enjoy the HUD as a very useful extra.

I want to regularly eyeball those 3 PO2 readings so that's the handset on my wrist.

I want the comfort in shit vis or if I'm a bit busy of the HUD.

I want a simple HUD like the Vision's. Solid greens, flashing greens, flashing reds, solid reds. Instant referral to handset for the details.

Works for me

Charlie

**Dave Sutton** · 5th February 2007, 14:09

Quote: (Originally Posted by silentscuba)

I dive a KISS Classic. I have an integrated Shearwater and a HUD from a different manufacturer. They are both independent from each other except for the 3 O2 cells.

Then they are not independant. A flood in one will place battery voltage down the sensor wires and into the other system. This is the *least desirable* system architecture imaginable. Any single point of failure mode that disables all monitoring is suboptimal (to say the very least)

Really, what I see here is a set of ingenious solutions to nonexistant problems. PICK ONE WAY and then get REALLY GOOD AT IT. Get good at DIVING and quit worrying about the nitpicky details of your rig. THEY ALL WORK.... so pick one and learn to use it. "Parachute systems" and "two combined modes" and "an orifice aded to my ECCR" and "redundancy in electonics (except we share cells so it's all really one system anyhow)" schemes are *really* not worth the effort. Higher parts count = more crap to maintain and a LOWER mean time between failures. Ya'll ought to study how *professional* life support engineers (IE: Aerospace and Medical life support system engineers) meet these design requirements. They design ONE system that is ROBUST and WELL DESIGNED and they rely on it. A fellow FIT Alumni just set the record for most logged time in EVA out of the space shuttle... their system is a ECCR *without any nonsense included*. It's a basic ECCR, Lithium Hydroxide scrubber, 3 cell PP02 monitoring mwith voting logic, and manual bypass valves. It works *every time*. Adding a KISS valve to it? Give me a break.

Similarly, the KISS system and it's spinoffs also work *EVERY TIME* as long as the diver is not afflicted with the stupids. So far that's not occured.

What I see generally is a simple insecurity problem..... if "some" system architecure is good, "more" must be better, eh? But this misses the point. If you are CONFIDENT in what you have, then more is not better... it's worse. And if you are not confident in your rig, you ought to either (A) get another rig, or more likely (B)pick another sport, because it's not the *rig* that has the problem, it's the *diver* because he's simply not secure in his skill set. I see this also with aviation... insecure amateur pilots add more and more and *more* crap into their airplanes to get over their *personal* insecurity. Has nothing to do with reliability, as the stuff that they already had was more than adequate. They then typically spend their entire flight *playing with their crap* (because they have way too much of it) and never look outta the window. Overall SA (situational awareness) is actually LOWER than if they had less, used it well, task-desaturated themselves, and *paid attention to what was going on* with the brain cells they free up.

Admiral Gorschkov, the architect of the modern Soviet Navy, had it EXACTLY right when he said:

"Better is the enemy of good enough"

"Improvements" become "dis-improvements" at some discrete point in any technical system. And this is not hypothetical... I'm at this moment workign as a design consultant to a government oriented engineering/manufacturing company for the design of a new ECCR that is a government contract item (50 units to be *delivered* within the next 90 days, actually, so it's not vaporware) and I'm working at the engineering architectural level on the system. We are not going to add complexity to the system, and it's gonna work 100% of the time, every time, with reliability to the 4th decimal place of 9's. We picked one mode of operation. More is not more... more is less.

Closing: I see rebreather systems on the boat here that show obvious lack of involvement with "the real world". I wonder if time would be better spent just taking "any old system" and then diving it a LOT and adapting to it, rather than continuously reinventing the wheel.

Pick a way. Both work. Use it well. Go diving. Enjoy the view outta your mask.

Dave Sutton

(Quite happy with EITHER system....)

Sutty · 5th February 2007, 14:26

Quote: (Originally Posted by Dave Sutton)

Then they are not independant. A flood in one will place battery voltage down the sensor wires and into the other system. This is the *least desirable* system architecture imaginable. Any single point of failure mode that disables all monitoring is suboptimal (to say the very least)

This is a very good point, and one that has been a frustration to me. I dive a Classic Kiss with Uri's HUD added - makes my life easier as I can run the unit without moving my arm to look at displays (good for photography). Uri's design is excellent and as well as having three seperate circuits (one for each cell) has resistors in the head which mean that you could flood/short out the HUD unit and the original Kiss displays carry on working (there is a small risk of effects from battery voltage with a major flood of the potted main electronics of the HUD). Admittedly if you flood the cell itself then that channel at least is screwed.
Unfortunately if you flood a Kiss display it can short out the cell and affect that channel on the HUD, but at least it only affects one cell due to the redundant nature of the Kiss displays.
This is what has stopped me going for a Shearwater instead of the Kiss displays (which I think is what Curt has done) - if I flood the Shearwater all my PO2 monitoring would fail.

What I wanted to get across was that if you do add something to your rig make sure you know how failures of the different parts of the system will affect other parts.

Neil

silentscuba · 5th February 2007, 14:31

Quote: (Originally Posted by Dave Sutton)

Then they are not independant. A flood in one will place battery voltage down the sensor wires and into the other system. This is the *least desirable* system architecture imaginable. Any single point of failure mode that disables all monitoring is suboptimal (to say the very least)

Wrong!!!! Both the Shearwater and the URI HUD will still operate without the other, even when flooded. They were both designed not to screw up the sensors if flooded (good design)!!!!!!. I feel that I have the most desirable combination with the best architecture

.

I actully had my Shearwater flood in the early days because of a bad O-Ring and my URI HUD worked just fine. I did a 100% flush at 20' and all three indicators reading correctly.

Sutty · 5th February 2007, 14:38

Quote: (Originally Posted by silentscuba)

Wrong!!!! Both the Shearwater and the URI HUD will still operate without the other, even when flooded. They were both designed not to screw up the sensors if flooded (good design)!!!!!!. I feel that I have the most desirable combination with the best architecture

.

I actully had my Shearwater flood in the early days because of a bad O-Ring and my URI HUD worked just fine. I did a 100% flush at 20' and all three indicators reading correctly.

Hi Curt. That is very interesting! Can you tell me anything of how the Shearwater prevents a flood shorting the two cables from a cell with seawater? Do you have the hard-wired version or the one with a Fischer connector plugging into the Shearwater?
Thanks

silentscuba · 5th February 2007, 15:45

Quote: (Originally Posted by Sutty)

Hi Curt. That is very interesting! Can you tell me anything of how the Shearwater prevents a flood shorting the two cables from a cell with seawater? Do you have the hard-wired version or the one with a Fischer connector plugging into the Shearwater?
Thanks

Bruce would be better at answereing your question about floods and shorting cables. All I know is that it is a fact that the HUD still worked ok with a flooded Shearwater.

I do have the Fisher Connector on my Shearwater and my URI HUD.

silentscuba · 5th February 2007, 16:01

One thing that seems to be left out here is that when you do have a problem, it is time to bailout. That option is always there and we should not rely on these systems to work properly if something is not looking to good, like a flooded computer housing, a cut wire, a connector that has come loose, etc.

When in doubt, bailout!!!!!!!

Sutty · 5th February 2007, 16:03

Quote: (Originally Posted by silentscuba)

I do have the Fisher Connector on my Shearwater and my URI HUD.

This is one of the things that concerns me. The Fischer into the Shearwater (like all Fischers) relies on a single Oring to protect the electronic connections. If this floods the saltwater can short out the signals from the cells, as these are simple cables to the cell this is the electrical equivalent of shorting out the cell, at which point NO system attached to the cell can be considered reliable.

In my personal experience if you flood the Fischer from the cells to Uri's HUD the HUD will give haywire signals (but the Kiss displays still work) - an easy way to see this is by not plugging the two halves of the Fischers together properly

It would be possible to protect from this as Uri has done by incorporating a high value resistor in the cable at the cell end, but this would very likely require a change to the Shearwater's input circuitry - I presume it has a cell terminating resistor of about 10K across the input - and moving the terminating resistor to inside the head next to the cell.

Sorry I know this is off-topic

silentscuba · 5th February 2007, 16:22

Quote: (Originally Posted by Gill Envy)

So Curt, it sounds like you have effectively created a manual injection eCCR. What you call it is not really important to me, but it sounds like the Sheerwater gives you a nice po2/deco integrated system and i'm guessing you use a second back up constant po2 computer as well...a VR3? The write up on it in the last ADM magazine made it seem very intuitive and streightforward, but i would have to say that it diverges from the notion of simplicity of the usual mCCR line of thinking.

I am fascinated by this evolution of mCCR's. I am very curious to see if the mCCR's continue having such a lack of fatal accidents associated with them, again, good training and vigilance not withstanding. It makes me want to run my eCCR's injection system on a low set point and inject manually even though i concede that it is still not completely comporable in "simplicity" and true mCCR mindset/habit formation. I'm guessing that there will be a trend to further integrate electronics into the mCCR and that the mortality rates will stay about the same and i'm very curious to see if this compells eCCR manufacturers to embrace manual injection at some point.

Oh, BTW, how have you addressed the increased flooding potential of internal counter lungs...have you modified your kit to have front mounted counter lungs like the Copis? If not, please explain your reasoning...this is one of the things that held me back from the KISS after being convinced that the threat of caustic cocktail was higher with the KISS style counter lungs.

And, possibly to clear up some myths, what are the average max depths of the mCCR divers you know of, including yourself.

g

\

I do use a Shearwater set at a constant PO2 as my back up computer. I can also plug this backup computer into my cable and use it as my primary if need be.

I have not found that the back mounted counterlungs are a problem for me. I have enough shit on my chest without having counterlungs there to. The KISS Classic does have a small water trap, and, between the ex-hail lung and the small trap, it can handle a fair amount of water. Anymore than just a small mistake, I would be bailing out anyway.

As far as depths go, I have always felt that I wanted to be comfortable at 250' and the KISS Classic does that just fine. Much deeper and you have to change a few things which is easy to do. I have also plummed for offboard gas. I have had my Classic to 260 ft.

5th February 2007, 13:36	#41 (permalink)
CharlieT Custom Title Allowed! Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Nov 2005 Location: London Posts: 449	Re: Differences between eCCR’s and mCCR’s design that may effect mortality rates Quote: (Originally Posted by moley) You really are a lovely bloke Mike. That's not his mother says Charlie
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5th February 2007, 13:47	#42 (permalink)
CharlieT Custom Title Allowed! Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Nov 2005 Location: London Posts: 449	Re: Differences between eCCR’s and mCCR’s design that may effect mortality rates Quote: (Originally Posted by dave t) Awhile ago I had a classic inspo lid with just one handset and a kiss valve attached, I used to set the handset to 0.7 and run my po2 at about 1.2 via the kiss valve. it worked very well, po2 was very stable, if I had to be very lax on ascent for some reason the handset would take over, it could even be easily switched to 1.3 for high po2 ascents in an emergency. Battery life was long cos there was hardly any solenoid action, calibration was easy, and more importantly I had the kiss style mindset right!!! sounds good? Well actually it isnt so good, I got to worry about is the handset going to work when I really need it, when it does will the solenoid stick open due to little use, will the solenoid stick closed and I wont notice until its too late. At least on a kiss unit there is no distraction of "will my parachute open" on a ECCR the electronics are working (and verifing) all the time In my opinion both systems are very good in the right hands but keep them seperate!! just my opinion Dave The voice of common sense and reason again! The Vision manual says you should regard your handset as your primary monitor and enjoy the HUD as a very useful extra. I want to regularly eyeball those 3 PO2 readings so that's the handset on my wrist. I want the comfort in shit vis or if I'm a bit busy of the HUD. I want a simple HUD like the Vision's. Solid greens, flashing greens, flashing reds, solid reds. Instant referral to handset for the details. Works for me Charlie
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5th February 2007, 14:09	#43 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Evolution Megalodon rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,907	Re: Differences between eCCR’s and mCCR’s design that may effect mortality rates Quote: (Originally Posted by silentscuba) I dive a KISS Classic. I have an integrated Shearwater and a HUD from a different manufacturer. They are both independent from each other except for the 3 O2 cells. Then they are not independant. A flood in one will place battery voltage down the sensor wires and into the other system. This is the least desirable system architecture imaginable. Any single point of failure mode that disables all monitoring is suboptimal (to say the very least) Really, what I see here is a set of ingenious solutions to nonexistant problems. PICK ONE WAY and then get REALLY GOOD AT IT. Get good at DIVING and quit worrying about the nitpicky details of your rig. THEY ALL WORK.... so pick one and learn to use it. "Parachute systems" and "two combined modes" and "an orifice aded to my ECCR" and "redundancy in electonics (except we share cells so it's all really one system anyhow)" schemes are really not worth the effort. Higher parts count = more crap to maintain and a LOWER mean time between failures. Ya'll ought to study how professional life support engineers (IE: Aerospace and Medical life support system engineers) meet these design requirements. They design ONE system that is ROBUST and WELL DESIGNED and they rely on it. A fellow FIT Alumni just set the record for most logged time in EVA out of the space shuttle... their system is a ECCR without any nonsense included. It's a basic ECCR, Lithium Hydroxide scrubber, 3 cell PP02 monitoring mwith voting logic, and manual bypass valves. It works every time. Adding a KISS valve to it? Give me a break. Similarly, the KISS system and it's spinoffs also work EVERY TIME as long as the diver is not afflicted with the stupids. So far that's not occured. What I see generally is a simple insecurity problem..... if "some" system architecure is good, "more" must be better, eh? But this misses the point. If you are CONFIDENT in what you have, then more is not better... it's worse. And if you are not confident in your rig, you ought to either (A) get another rig, or more likely (B)pick another sport, because it's not the rig that has the problem, it's the diver because he's simply not secure in his skill set. I see this also with aviation... insecure amateur pilots add more and more and more crap into their airplanes to get over their personal insecurity. Has nothing to do with reliability, as the stuff that they already had was more than adequate. They then typically spend their entire flight playing with their crap (because they have way too much of it) and never look outta the window. Overall SA (situational awareness) is actually LOWER than if they had less, used it well, task-desaturated themselves, and paid attention to what was going on with the brain cells they free up. Admiral Gorschkov, the architect of the modern Soviet Navy, had it EXACTLY right when he said: "Better is the enemy of good enough" "Improvements" become "dis-improvements" at some discrete point in any technical system. And this is not hypothetical... I'm at this moment workign as a design consultant to a government oriented engineering/manufacturing company for the design of a new ECCR that is a government contract item (50 units to be delivered within the next 90 days, actually, so it's not vaporware) and I'm working at the engineering architectural level on the system. We are not going to add complexity to the system, and it's gonna work 100% of the time, every time, with reliability to the 4th decimal place of 9's. We picked one mode of operation. More is not more... more is less. Closing: I see rebreather systems on the boat here that show obvious lack of involvement with "the real world". I wonder if time would be better spent just taking "any old system" and then diving it a LOT and adapting to it, rather than continuously reinventing the wheel. Pick a way. Both work. Use it well. Go diving. Enjoy the view outta your mask. Dave Sutton (Quite happy with EITHER system....) __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com
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5th February 2007, 14:26	#44 (permalink)
Sutty Classic Kiss diver Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Jun 2005 Location: Glossop, Derbyshire, UK Posts: 834	Re: Differences between eCCR’s and mCCR’s design that may effect mortality rates Quote: (Originally Posted by Dave Sutton) Then they are not independant. A flood in one will place battery voltage down the sensor wires and into the other system. This is the least desirable system architecture imaginable. Any single point of failure mode that disables all monitoring is suboptimal (to say the very least) This is a very good point, and one that has been a frustration to me. I dive a Classic Kiss with Uri's HUD added - makes my life easier as I can run the unit without moving my arm to look at displays (good for photography). Uri's design is excellent and as well as having three seperate circuits (one for each cell) has resistors in the head which mean that you could flood/short out the HUD unit and the original Kiss displays carry on working (there is a small risk of effects from battery voltage with a major flood of the potted main electronics of the HUD). Admittedly if you flood the cell itself then that channel at least is screwed. Unfortunately if you flood a Kiss display it can short out the cell and affect that channel on the HUD, but at least it only affects one cell due to the redundant nature of the Kiss displays. This is what has stopped me going for a Shearwater instead of the Kiss displays (which I think is what Curt has done) - if I flood the Shearwater all my PO2 monitoring would fail. What I wanted to get across was that if you do add something to your rig make sure you know how failures of the different parts of the system will affect other parts. Neil __________________ Never forget that life is a finite resource. Last edited by Sutty : 5th February 2007 at 14:29.
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5th February 2007, 14:31	#45 (permalink)
silentscuba rEvo CCR Driver Current Rebreather/s: Classic Kiss rEvo Other Rebreather/s: Inspiration Classic rEvo Join Date: Jun 2005 Location: Mill Creek, WA USA Posts: 612	Re: Differences between eCCR’s and mCCR’s design that may effect mortality rates Quote: (Originally Posted by Dave Sutton) Then they are not independant. A flood in one will place battery voltage down the sensor wires and into the other system. This is the least desirable system architecture imaginable. Any single point of failure mode that disables all monitoring is suboptimal (to say the very least) Wrong!!!! Both the Shearwater and the URI HUD will still operate without the other, even when flooded. They were both designed not to screw up the sensors if flooded (good design)!!!!!!. I feel that I have the most desirable combination with the best architecture . I actully had my Shearwater flood in the early days because of a bad O-Ring and my URI HUD worked just fine. I did a 100% flush at 20' and all three indicators reading correctly. __________________ Curt McNamee rEvo CCR Diver KISS CCR Diver www.silentscuba.com
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5th February 2007, 14:38	#46 (permalink)
Sutty Classic Kiss diver Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Jun 2005 Location: Glossop, Derbyshire, UK Posts: 834	Re: Differences between eCCR’s and mCCR’s design that may effect mortality rates Quote: (Originally Posted by silentscuba) Wrong!!!! Both the Shearwater and the URI HUD will still operate without the other, even when flooded. They were both designed not to screw up the sensors if flooded (good design)!!!!!!. I feel that I have the most desirable combination with the best architecture . I actully had my Shearwater flood in the early days because of a bad O-Ring and my URI HUD worked just fine. I did a 100% flush at 20' and all three indicators reading correctly. Hi Curt. That is very interesting! Can you tell me anything of how the Shearwater prevents a flood shorting the two cables from a cell with seawater? Do you have the hard-wired version or the one with a Fischer connector plugging into the Shearwater? Thanks __________________ Never forget that life is a finite resource.
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5th February 2007, 15:45	#47 (permalink)
silentscuba rEvo CCR Driver Current Rebreather/s: Classic Kiss rEvo Other Rebreather/s: Inspiration Classic rEvo Join Date: Jun 2005 Location: Mill Creek, WA USA Posts: 612	Re: Differences between eCCR’s and mCCR’s design that may effect mortality rates Quote: (Originally Posted by Sutty) Hi Curt. That is very interesting! Can you tell me anything of how the Shearwater prevents a flood shorting the two cables from a cell with seawater? Do you have the hard-wired version or the one with a Fischer connector plugging into the Shearwater? Thanks Bruce would be better at answereing your question about floods and shorting cables. All I know is that it is a fact that the HUD still worked ok with a flooded Shearwater. I do have the Fisher Connector on my Shearwater and my URI HUD. __________________ Curt McNamee rEvo CCR Diver KISS CCR Diver www.silentscuba.com
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5th February 2007, 16:01	#48 (permalink)
silentscuba rEvo CCR Driver Current Rebreather/s: Classic Kiss rEvo Other Rebreather/s: Inspiration Classic rEvo Join Date: Jun 2005 Location: Mill Creek, WA USA Posts: 612	Re: Differences between eCCR’s and mCCR’s design that may effect mortality rates One thing that seems to be left out here is that when you do have a problem, it is time to bailout. That option is always there and we should not rely on these systems to work properly if something is not looking to good, like a flooded computer housing, a cut wire, a connector that has come loose, etc. When in doubt, bailout!!!!!!! __________________ Curt McNamee rEvo CCR Diver KISS CCR Diver www.silentscuba.com
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5th February 2007, 16:03	#49 (permalink)
Sutty Classic Kiss diver Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Jun 2005 Location: Glossop, Derbyshire, UK Posts: 834	Re: Differences between eCCR’s and mCCR’s design that may effect mortality rates Quote: (Originally Posted by silentscuba) I do have the Fisher Connector on my Shearwater and my URI HUD. This is one of the things that concerns me. The Fischer into the Shearwater (like all Fischers) relies on a single Oring to protect the electronic connections. If this floods the saltwater can short out the signals from the cells, as these are simple cables to the cell this is the electrical equivalent of shorting out the cell, at which point NO system attached to the cell can be considered reliable. In my personal experience if you flood the Fischer from the cells to Uri's HUD the HUD will give haywire signals (but the Kiss displays still work) - an easy way to see this is by not plugging the two halves of the Fischers together properly It would be possible to protect from this as Uri has done by incorporating a high value resistor in the cable at the cell end, but this would very likely require a change to the Shearwater's input circuitry - I presume it has a cell terminating resistor of about 10K across the input - and moving the terminating resistor to inside the head next to the cell. Sorry I know this is off-topic __________________ Never forget that life is a finite resource.
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5th February 2007, 16:22	#50 (permalink)
silentscuba rEvo CCR Driver Current Rebreather/s: Classic Kiss rEvo Other Rebreather/s: Inspiration Classic rEvo Join Date: Jun 2005 Location: Mill Creek, WA USA Posts: 612	Re: Differences between eCCR’s and mCCR’s design that may effect mortality rates Quote: (Originally Posted by Gill Envy) So Curt, it sounds like you have effectively created a manual injection eCCR. What you call it is not really important to me, but it sounds like the Sheerwater gives you a nice po2/deco integrated system and i'm guessing you use a second back up constant po2 computer as well...a VR3? The write up on it in the last ADM magazine made it seem very intuitive and streightforward, but i would have to say that it diverges from the notion of simplicity of the usual mCCR line of thinking. I am fascinated by this evolution of mCCR's. I am very curious to see if the mCCR's continue having such a lack of fatal accidents associated with them, again, good training and vigilance not withstanding. It makes me want to run my eCCR's injection system on a low set point and inject manually even though i concede that it is still not completely comporable in "simplicity" and true mCCR mindset/habit formation. I'm guessing that there will be a trend to further integrate electronics into the mCCR and that the mortality rates will stay about the same and i'm very curious to see if this compells eCCR manufacturers to embrace manual injection at some point. Oh, BTW, how have you addressed the increased flooding potential of internal counter lungs...have you modified your kit to have front mounted counter lungs like the Copis? If not, please explain your reasoning...this is one of the things that held me back from the KISS after being convinced that the threat of caustic cocktail was higher with the KISS style counter lungs. And, possibly to clear up some myths, what are the average max depths of the mCCR divers you know of, including yourself. g \ I do use a Shearwater set at a constant PO2 as my back up computer. I can also plug this backup computer into my cable and use it as my primary if need be. I have not found that the back mounted counterlungs are a problem for me. I have enough shit on my chest without having counterlungs there to. The KISS Classic does have a small water trap, and, between the ex-hail lung and the small trap, it can handle a fair amount of water. Anymore than just a small mistake, I would be bailing out anyway. As far as depths go, I have always felt that I wanted to be comfortable at 250' and the KISS Classic does that just fine. Much deeper and you have to change a few things which is easy to do. I have also plummed for offboard gas. I have had my Classic to 260 ft. __________________ Curt McNamee rEvo CCR Diver KISS CCR Diver www.silentscuba.com Last edited by silentscuba : 5th February 2007 at 16:31.
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