Read and Learn......

jptaylor9 · 18th January 2007, 08:25

Quote: (Originally Posted by UKSteve)

Pete S & Admin / Moderators...

I am very conscious that this thread might be considered by some to be going off topic due to my wittering... though it might also be considered to be going to the core of the tragic loss of Nigel.

.. if you consider it proper, could you perhaps strip out the auto switch-on discussions into a separate thread?

Regards

Steve

I think this is the correct forum to discuss this event, this is not the "Memorial Forum" (IMHO)

JT

decoweenie · 18th January 2007, 08:57

Quote: (Originally Posted by UKSteve)

I personally would prefer to see the handset switching on automatically...

This is only my own opinion...

CCR diving requires that the diver follows a set of rules, but it could be summarized into 2 basic things:

Prebreath the unit (before the dive)
Know your PO2 (at all time)

Either of those 2 things require having the unit fully functional and turned on.

So why does we need the unit to be turned on automatically ?

Even diving OC needs the breathing mechanism to be on - which is the tank. The part that regulates the health of the breathing mechanism on a CCR is the SP controller, so it also need to be on before the dive.

Both are the responsibility of the diver.

However, there could be instances that an automatical-on feature would be useful on an eCCR. Could anyone think of some ?

silent running · 18th January 2007, 09:16

Quote: (Originally Posted by decoweenie)

This is only my own opinion...

CCR diving requires that the diver follows a set of rules, but it could be summarized into 2 basic things:

Prebreath the unit (before the dive)
Know your PO2 (at all time)

Either of those 2 things require having the unit fully functional and turned on.

So why does we need the unit to be turned on automatically ?

Even diving OC needs the breathing mechanism to be on - which is the tank. The part that regulates the health of the breathing mechanism on a CCR is the SP controller, so it also need to be on before the dive.

Both are the responsibility of the diver.

However, there could be instances that an automatical-on feature would be useful on an eCCR. Could anyone think of some ?

Phi, if somebody were to turn a unit off after prebreathing, in order to save the expensive and possibly troublesome to replace batteries and jumps in without turning the power back on. It's happened before and it will almost certainly happen again, right?

And BTW, I was not taught to prebreathe the Prism and I don't think most Prism divers do either, unless maybe if they're diving in the Polar regions and spend a significant time outdoors in extreme cold...

UKSteve · 18th January 2007, 09:23

Quote: (Originally Posted by decoweenie)

However, there could be instances that an automatical-on feature would be useful on an eCCR. Could anyone think of some ?

Phi,

Putting it pretty unsubtly...if the APD units did what I described above then there is a very good possibility that this whole thread would not exist. Nigel could have heard the alarm, looked at his handset and then bailed out. Sadly I believe he is not the first to die in this manner.

Steve

decoweenie · 18th January 2007, 09:23

Quote: (Originally Posted by silent running)

...if somebody were to turn a unit off after prebreathing, in order to save the expensive and possibly troublesome to replace batteries and jumps in without turning the power back on. It's happened before and it will almost certainly happen again, right?

Fair example.

However, it still violates rule (2): Always know your PO2 (at all time).

Quote:

...I was not taught to prebreathe the Prism and I don't think most Prism divers do either, unless maybe if they're diving in the Polar regions and spend a significant time outdoors in extreme cold...

Does that mean that Prism divers only see pre-breath as a possible scrubber start-up procedure rather than a method to test the functionality of the unit (i.e. SP are kept, solenoid firing, O2 tank on, etc) ?

***caveseeker7*** · 18th January 2007, 09:31

Quote: (Originally Posted by silent running)

And BTW, I was not taught to prebreathe the Prism and I don't think most Prism divers do either

I was and I am, both on PRISM and Sport Kiss.

webhead · 18th January 2007, 09:42

Quote: (Originally Posted by PhilSiswick)

Is there a risk that you could end up with a situation where an uncalibrated unit switched on automatically and does more harm than good. You wouldn't know that the calibration wasn't correct. If the unit isn't switched on, you should bailout - the safe option. Also, how would you deal with the self-test routine? Would you skip that if you leapt into the water with the handsets switched off - not a good idea, I'd say, but would a self-test be valid underwater?

You could put a time-out in, that the unit only auto-switches on if the period between self-test and/or calibration was up to x hours before, but that still leaves you with a strong chance that you could hit the water and the unit wouldn't switch on.

I'd love to know why AP have not gone down this route, but I suspect that there is a pretty good reason.

Cheers,

So that has been the debate - is it better to have a unit attempt to maintain PO2 with possibly out of cal sensors or have a unit that must be turned on by the user. This leads into the next debate - how much do you require/depend on the diver and how much is automatic.

Think about this - you depend on the user to do a proper calibration. You can't program a computer to check the quality of your O2 supply (e.g. the computer can't tell it's NX80 vs 99% O2 before cal). So why can't you depend on the diver to turn the unit on? Or, if the unit does have an auto-on feature, what is to prevent the diver from letting the unit turn on automatically and going hypoxic while breathing the unit while waiting on the boat? This is where the debate begins and different methods on different units. I believe there is a set of electronics that does something different in an attempt to cover all these bases yet I'm not aware of one that covers all.

As for your statement "You wouldn't know that the calibration wasn't correct.", I would say that you should know if your cells are calibrated. You should know the last time you dove the unit and how long, the last time you calibrated, and how old your cells are. And if you don't remember any of these then your cells are out of calibration. So you now know.

If you are referring to the predive sequence of the Vision electronics, that unit does sense pressure and will bypass the predive IF it senses the unit has been switched on underwater and thus prevent the user from doing a calibration in dive mode. It also logs that the dive was done without the predive, etc. Other units power on differently (e.g. meg electronics do no have pre-dive sequence).

The Visions and even the older Inspiration electronics do have a calibrate/must calibrate feature essentially telling you that you can or must calibrate before a dive. The classic would let you bypass must cal allowing the user to go into dive mode if the handset was turned on (possible power cycle) underwater.

And you can determine if the cells are correct if you know what the PO2 of your diluent is at the depth you are at (I'll assume we can do this math).

"If the unit isn't switched on, you should bailout - the safe option." Bailing out and aborting a dive has never resulted in an accident that I'm aware of.

webhead · 18th January 2007, 09:47

Quote: (Originally Posted by decoweenie)

However, there could be instances that an automatical-on feature would be useful on an eCCR. Could anyone think of some ?

If you have a unit that has an automatic off feature. If you pre-breath and leave the unit on and it turns itself automatically, I would hope that it would turn itself back on automatically. I also would hope the diver is aware of this and make sure the unit is on before ever breathing on it (i.e. know your PO2).

Sort of like automatic locks on cars. If my car locks the door when I put the car in drive, I think it should unlock at least the driver's door when I put it in park/shut the engine off.

I can't say specifically if there is a unit out there that does this. But that is a situation for you.

webhead · 18th January 2007, 09:49

Quote: (Originally Posted by caveseeker7)

I was and I am, both on PRISM and Sport Kiss.

Curious, were you trained to prereath or not to prebreath the prism? Do you anyways?

UKSteve · 18th January 2007, 09:50

Quote: (Originally Posted by webhead)

So that has been the debate - is it better to have a unit attempt to maintain PO2 with possibly out of cal sensors or have a unit that must be turned on by the user. This leads into the next debate - how much do you require/depend on the diver and how much is automatic. ... snip....

"If the unit isn't switched on, you should bailout - the safe option." Bailing out and aborting a dive has never resulted in an accident that I'm aware of.

The point I am trying to persue is not having the unit switch on automatically under pressure so you can go diving or even so you can remain on the loop... but simply to build into the unit an electronic kick in the arse to snap you out of whatever distraction has caused you to both jump into the water with the unit switched off and also to fail to monitor the handset(s).

The problem is that the process of descending and adding dil to the loop "hides" the fact the unit is not working... you have gas to breath and you feel fine.

Yea ...sure...in an ideal world this could never happen - but circumstances tragically show it does... and if it saved just one life in the future I think it would be worth it.

Steve

18th January 2007, 08:25	#41 (permalink)
jptaylor9 Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: London, UK Posts: 318	Re: Read and Learn...... Quote: (Originally Posted by UKSteve) Pete S & Admin / Moderators... I am very conscious that this thread might be considered by some to be going off topic due to my wittering... though it might also be considered to be going to the core of the tragic loss of Nigel. .. if you consider it proper, could you perhaps strip out the auto switch-on discussions into a separate thread? Regards Steve I think this is the correct forum to discuss this event, this is not the "Memorial Forum" (IMHO) JT
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18th January 2007, 08:57	#42 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,487	Re: Read and Learn...... Quote: (Originally Posted by UKSteve) I personally would prefer to see the handset switching on automatically... This is only my own opinion... CCR diving requires that the diver follows a set of rules, but it could be summarized into 2 basic things: Prebreath the unit (before the dive) Know your PO2 (at all time) Either of those 2 things require having the unit fully functional and turned on. So why does we need the unit to be turned on automatically ? Even diving OC needs the breathing mechanism to be on - which is the tank. The part that regulates the health of the breathing mechanism on a CCR is the SP controller, so it also need to be on before the dive. Both are the responsibility of the diver. However, there could be instances that an automatical-on feature would be useful on an eCCR. Could anyone think of some ? __________________ "...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..." - Rebreather World PM
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18th January 2007, 09:16	#43 (permalink)
silent running Mature mouth breather Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Jun 2005 Location: U.S.A. Brooklyn, New York Posts: 1,832	Re: Read and Learn...... Quote: (Originally Posted by decoweenie) This is only my own opinion... CCR diving requires that the diver follows a set of rules, but it could be summarized into 2 basic things: Prebreath the unit (before the dive) Know your PO2 (at all time) Either of those 2 things require having the unit fully functional and turned on. So why does we need the unit to be turned on automatically ? Even diving OC needs the breathing mechanism to be on - which is the tank. The part that regulates the health of the breathing mechanism on a CCR is the SP controller, so it also need to be on before the dive. Both are the responsibility of the diver. However, there could be instances that an automatical-on feature would be useful on an eCCR. Could anyone think of some ? Phi, if somebody were to turn a unit off after prebreathing, in order to save the expensive and possibly troublesome to replace batteries and jumps in without turning the power back on. It's happened before and it will almost certainly happen again, right? And BTW, I was not taught to prebreathe the Prism and I don't think most Prism divers do either, unless maybe if they're diving in the Polar regions and spend a significant time outdoors in extreme cold...
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18th January 2007, 09:23	#44 (permalink)
UKSteve Steve Collard Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Jul 2005 Location: Weymouth, UK Posts: 598	Re: Read and Learn...... Quote: (Originally Posted by decoweenie) However, there could be instances that an automatical-on feature would be useful on an eCCR. Could anyone think of some ? Phi, Putting it pretty unsubtly...if the APD units did what I described above then there is a very good possibility that this whole thread would not exist. Nigel could have heard the alarm, looked at his handset and then bailed out. Sadly I believe he is not the first to die in this manner. Steve Last edited by UKSteve : 18th January 2007 at 09:26.
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18th January 2007, 09:23	#45 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,487	Re: Read and Learn...... Quote: (Originally Posted by silent running) ...if somebody were to turn a unit off after prebreathing, in order to save the expensive and possibly troublesome to replace batteries and jumps in without turning the power back on. It's happened before and it will almost certainly happen again, right? Fair example. However, it still violates rule (2): Always know your PO2 (at all time). Quote: ...I was not taught to prebreathe the Prism and I don't think most Prism divers do either, unless maybe if they're diving in the Polar regions and spend a significant time outdoors in extreme cold... Does that mean that Prism divers only see pre-breath as a possible scrubber start-up procedure rather than a method to test the functionality of the unit (i.e. SP are kept, solenoid firing, O2 tank on, etc) ? __________________ "...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..." - Rebreather World PM
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18th January 2007, 09:31	#46 (permalink)
*caveseeker7* Who loves ya, baby Current Rebreather/s: Sport Kiss Other Rebreather/s: Prism Topaz Join Date: Jan 2005 Location: Too far from Neverland Posts: 5,451	Re: Read and Learn...... Quote: (Originally Posted by silent running) And BTW, I was not taught to prebreathe the Prism and I don't think most Prism divers do either I was and I am, both on PRISM and Sport Kiss. __________________ Cheers Stefan "Political Correctness is a doctrine, fostered by a delusional, illogical minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"
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18th January 2007, 09:42	#47 (permalink)
webhead Earning the green stuff.. Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Megalodon Join Date: Mar 2006 Location: East central Florida Posts: 284	Re: Read and Learn...... Quote: (Originally Posted by PhilSiswick) Is there a risk that you could end up with a situation where an uncalibrated unit switched on automatically and does more harm than good. You wouldn't know that the calibration wasn't correct. If the unit isn't switched on, you should bailout - the safe option. Also, how would you deal with the self-test routine? Would you skip that if you leapt into the water with the handsets switched off - not a good idea, I'd say, but would a self-test be valid underwater? You could put a time-out in, that the unit only auto-switches on if the period between self-test and/or calibration was up to x hours before, but that still leaves you with a strong chance that you could hit the water and the unit wouldn't switch on. I'd love to know why AP have not gone down this route, but I suspect that there is a pretty good reason. Cheers, So that has been the debate - is it better to have a unit attempt to maintain PO2 with possibly out of cal sensors or have a unit that must be turned on by the user. This leads into the next debate - how much do you require/depend on the diver and how much is automatic. Think about this - you depend on the user to do a proper calibration. You can't program a computer to check the quality of your O2 supply (e.g. the computer can't tell it's NX80 vs 99% O2 before cal). So why can't you depend on the diver to turn the unit on? Or, if the unit does have an auto-on feature, what is to prevent the diver from letting the unit turn on automatically and going hypoxic while breathing the unit while waiting on the boat? This is where the debate begins and different methods on different units. I believe there is a set of electronics that does something different in an attempt to cover all these bases yet I'm not aware of one that covers all. As for your statement "You wouldn't know that the calibration wasn't correct.", I would say that you should know if your cells are calibrated. You should know the last time you dove the unit and how long, the last time you calibrated, and how old your cells are. And if you don't remember any of these then your cells are out of calibration. So you now know. If you are referring to the predive sequence of the Vision electronics, that unit does sense pressure and will bypass the predive IF it senses the unit has been switched on underwater and thus prevent the user from doing a calibration in dive mode. It also logs that the dive was done without the predive, etc. Other units power on differently (e.g. meg electronics do no have pre-dive sequence). The Visions and even the older Inspiration electronics do have a calibrate/must calibrate feature essentially telling you that you can or must calibrate before a dive. The classic would let you bypass must cal allowing the user to go into dive mode if the handset was turned on (possible power cycle) underwater. And you can determine if the cells are correct if you know what the PO2 of your diluent is at the depth you are at (I'll assume we can do this math). "If the unit isn't switched on, you should bailout - the safe option." Bailing out and aborting a dive has never resulted in an accident that I'm aware of. __________________ "These are not the droids you are looking for.... move along" - Obi-Wan Kenobi
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18th January 2007, 09:47	#48 (permalink)
webhead Earning the green stuff.. Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Megalodon Join Date: Mar 2006 Location: East central Florida Posts: 284	Re: Read and Learn...... Quote: (Originally Posted by decoweenie) However, there could be instances that an automatical-on feature would be useful on an eCCR. Could anyone think of some ? If you have a unit that has an automatic off feature. If you pre-breath and leave the unit on and it turns itself automatically, I would hope that it would turn itself back on automatically. I also would hope the diver is aware of this and make sure the unit is on before ever breathing on it (i.e. know your PO2). Sort of like automatic locks on cars. If my car locks the door when I put the car in drive, I think it should unlock at least the driver's door when I put it in park/shut the engine off. I can't say specifically if there is a unit out there that does this. But that is a situation for you. __________________ "These are not the droids you are looking for.... move along" - Obi-Wan Kenobi
(Online)

18th January 2007, 09:49	#49 (permalink)
webhead Earning the green stuff.. Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Inspiration Vision Evolution Megalodon Join Date: Mar 2006 Location: East central Florida Posts: 284	Re: Read and Learn...... Quote: (Originally Posted by caveseeker7) I was and I am, both on PRISM and Sport Kiss. Curious, were you trained to prereath or not to prebreath the prism? Do you anyways? __________________ "These are not the droids you are looking for.... move along" - Obi-Wan Kenobi
(Online)

18th January 2007, 09:50	#50 (permalink)
UKSteve Steve Collard Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Jul 2005 Location: Weymouth, UK Posts: 598	Re: Read and Learn...... Quote: (Originally Posted by webhead) So that has been the debate - is it better to have a unit attempt to maintain PO2 with possibly out of cal sensors or have a unit that must be turned on by the user. This leads into the next debate - how much do you require/depend on the diver and how much is automatic. ... snip.... "If the unit isn't switched on, you should bailout - the safe option." Bailing out and aborting a dive has never resulted in an accident that I'm aware of. The point I am trying to persue is not having the unit switch on automatically under pressure so you can go diving or even so you can remain on the loop... but simply to build into the unit an electronic kick in the arse to snap you out of whatever distraction has caused you to both jump into the water with the unit switched off and also to fail to monitor the handset(s). The problem is that the process of descending and adding dil to the loop "hides" the fact the unit is not working... you have gas to breath and you feel fine. Yea ...sure...in an ideal world this could never happen - but circumstances tragically show it does... and if it saved just one life in the future I think it would be worth it. Steve Last edited by UKSteve : 18th January 2007 at 09:54.
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