Inspiration Fatalities
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1. The placement of the 3 oxygen sensors is ill-considered. Warm moist gas which has left the scrubber unit passes over the sensors. This results in condensation on the cell walls which affects the voltage (and hence the measured ppO2) read. External condensation can be mitigated by blowing cold dry diluent over the sensors, but this must be done regularly. There is nothing that can be done about internal condensation.
The implication of this point is that you cannot be sure what the real ppO2 of the loop is. As the ppO2 is controlled electronically, there is significant risk here.
2. There are 2 computers driving the unit - master and slave. The idea is that should the master fail, the slave would take control. Both units are driven by the same power source - not too smart.
3. Addition of oxygen to the loop is automatic but addition of diluent is not. It requires manual addition and thus the ppO2 in the loop can rise to dangerous levels without any action taking place.
4. Warnings are via a beeper and the displays. There is some
suggestion that users have been unable to hear the beeper underwater and this has been implicated in some deaths on the unit.
There are some other issues more related to CCR's in general. Many Inspiration divers seem to spend an inordinate portion of their dive looking at the handsets to make sure all appears ok. Personally, I think this takes away from the dive. You also have to consider the risk to life-support electronics underwater, how they handle differences in ppO2 registered by the cells etc.
Some users also tend to push their luck in terms of solo diving, not carrying sufficient OC bailout, "improving" the unit with home-made modifications etc.
Bad things about the Inspiration
1/ It uses the same 02 sensors that are used in 02 analysers, anyone who has used an o2 analyser will be familiar with how unreliable these things can be, how often they need recalibrating and how much care you have to treat these with. These things are hardly high tech state of the art electronics, its okay when you can recalibrate and reanalyse your gas in the diveshop, but when you are underwater, its not quite so easy.
2/ The Inspiration does not have a proper voting logic when deciding what the PO2 in the breathing loop is. The unit has three 02 sensors, it makes its decisions on the PO2 on the "best two out of three".
3/ The air in the breathing loop in a rebreather is very moist. The
analysers are in this moist environment on an Inspiration, which is not the best conditions for the analysers to work accurately. The O2 cells get so damp on a dive that often you will see Inspiration divers drying them out between dives. You have to ask why the do this, the answer is "the work better when dry", therefore the cells will give you accurate readings at the begining of the dive, but who knows how good they are after you have been under water for an hour or so.
4/ The electronics in the handsets are unreliable and often fail.
5/ 02 sensors should be calibrated across the range of pressures that they are to be used, you can only calibrate them on the surface, you cant calibrate them at depth.
There are, no-doubt, many other issues, but these are the main ones that I am familiar with.
Some people I know who dive them in the UK call them "The Yellow Peril" (after Cato, the mad servant of Inspector Clouseau in the Pink Panther films), Why? Because you never know when its going to strike.
--another--
I cant see how you can say "lets get some facts here", the issues that have been listed regarding the sensors are factual, not just heresay, go and ask anyone who has dived an Inspiration to see how often they have sensor problems, or handset problems.
The unit is a life support system, it mixes the gas you breath to a
preset po2, the reliability of that po2 is paramount. If there are
"issues" regarding the units ability to accurately measures this and react accordingly, do you think its a good idea to go and dive on one.
If you compare the design of an Inspiration to a CIS Lunar, or a
Biomarine unit, you will begin to see the difference between a badly designed CCR and a well designed CCR.
And thats before you get to the issue of how well trained the people are who are using them.
The implication of this point is that you cannot be sure what the real ppO2 of the loop is. As the ppO2 is controlled electronically, there is significant risk here.
2. There are 2 computers driving the unit - master and slave. The idea is that should the master fail, the slave would take control. Both units are driven by the same power source - not too smart.
3. Addition of oxygen to the loop is automatic but addition of diluent is not. It requires manual addition and thus the ppO2 in the loop can rise to dangerous levels without any action taking place.
4. Warnings are via a beeper and the displays. There is some
suggestion that users have been unable to hear the beeper underwater and this has been implicated in some deaths on the unit.
There are some other issues more related to CCR's in general. Many Inspiration divers seem to spend an inordinate portion of their dive looking at the handsets to make sure all appears ok. Personally, I think this takes away from the dive. You also have to consider the risk to life-support electronics underwater, how they handle differences in ppO2 registered by the cells etc.
Some users also tend to push their luck in terms of solo diving, not carrying sufficient OC bailout, "improving" the unit with home-made modifications etc.
Bad things about the Inspiration
1/ It uses the same 02 sensors that are used in 02 analysers, anyone who has used an o2 analyser will be familiar with how unreliable these things can be, how often they need recalibrating and how much care you have to treat these with. These things are hardly high tech state of the art electronics, its okay when you can recalibrate and reanalyse your gas in the diveshop, but when you are underwater, its not quite so easy.
2/ The Inspiration does not have a proper voting logic when deciding what the PO2 in the breathing loop is. The unit has three 02 sensors, it makes its decisions on the PO2 on the "best two out of three".
3/ The air in the breathing loop in a rebreather is very moist. The
analysers are in this moist environment on an Inspiration, which is not the best conditions for the analysers to work accurately. The O2 cells get so damp on a dive that often you will see Inspiration divers drying them out between dives. You have to ask why the do this, the answer is "the work better when dry", therefore the cells will give you accurate readings at the begining of the dive, but who knows how good they are after you have been under water for an hour or so.
4/ The electronics in the handsets are unreliable and often fail.
5/ 02 sensors should be calibrated across the range of pressures that they are to be used, you can only calibrate them on the surface, you cant calibrate them at depth.
There are, no-doubt, many other issues, but these are the main ones that I am familiar with.
Some people I know who dive them in the UK call them "The Yellow Peril" (after Cato, the mad servant of Inspector Clouseau in the Pink Panther films), Why? Because you never know when its going to strike.
--another--
I cant see how you can say "lets get some facts here", the issues that have been listed regarding the sensors are factual, not just heresay, go and ask anyone who has dived an Inspiration to see how often they have sensor problems, or handset problems.
The unit is a life support system, it mixes the gas you breath to a
preset po2, the reliability of that po2 is paramount. If there are
"issues" regarding the units ability to accurately measures this and react accordingly, do you think its a good idea to go and dive on one.
If you compare the design of an Inspiration to a CIS Lunar, or a
Biomarine unit, you will begin to see the difference between a badly designed CCR and a well designed CCR.
And thats before you get to the issue of how well trained the people are who are using them.
Someone on another board once bubbled...
1. The placement of the 3 oxygen sensors is ill-considered. Warm moist
gas which has left the scrubber unit passes over the sensors. This results in condensation on the cell walls which affects the voltage (and hence the measured ppO2) read. External condensation can be mitigated by blowing cold dry diluent over the sensors, but this must be done regularly. There is nothing that can be done about internal condensation.
Correct. ALL CCR rebreathers suffer the same problem. The reason we dry the head is to stop corrosion of the contacts and connectors. The O2 Cell is coated to stop the water affecting it. The moisture in the CCR gas is one of its benefits (no more dry throat after a dive). The sensors need to be in the loop before you breath the gas and downstream of the O2 injector, WHere would you put them?
The implication of this point is that you cannot be sure what the real ppO2 of the loop is. As the ppO2 is controlled electronically, there is significant risk here.
The sensors are just downstream of the injection point for a reason. They do reflect the O2 content well. I have a 4th sensor inserted a bit further downstream from them for my VR3. It agrees very well. Little risk here. The Royal Navy tested the unit extensively and praised the O2 control of the unit. Fact not rumour
2. There are 2 computers driving the unit - master and slave. The idea is that should the master fail, the slave would take control. Both units are driven by the same power source - not too smart.
Not true. Each controller has its own battery. Each is individually load tested at 6 second intervals throughout the dive. Failure of one unit does NOT effect the other
3. Addition of oxygen to the loop is automatic but addition of diluent is not. It requires manual addition and thus the ppO2 in the loop can rise to dangerous levels without any action taking place.
failure of addition of diluent will NOT raise the O2 in any way shape or form. The only time diluent addition is an issue is on the descent and its pretty obvious that you need to add some (ie you cant breath). Most of us fits Auto Diluent addition valves
4. Warnings are via a beeper and the displays. There is some
suggestion that users have been unable to hear the beeper underwater and this has been implicated in some deaths on the unit.
I'm one of the folks that cant hear the beeper on my unit (can hear it on others), I just had to move the sounder further away from my head. Your buddy will hear your beeper and expect you to do something about it. You can also monitor the gauges
There are some other issues more related to CCR's in general. Many Inspiration divers seem to spend an inordinate portion of their dive looking at the handsets to make sure all appears ok. Personally, I think this takes away from the dive. Peronally I think a once a min look at handset is no different from checking on your buddy at correct intervals, its only an issue on your first few dives before it becomes habit, dont you check your guages? You also have to consider the risk to life-support electronics underwater, how they handle differences in ppO2 registered by the cells etc.Dive computers, lights etc , all electronic and all used by most divers
Some users also tend to push their luck in terms of solo diving, not carrying sufficient OC bailout, "improving" the unit with home-made modifications etc. they get what they deserve, in fact this is the category most Inspiration incidents fall into. Improving the unit is fine within reason, The two most common are the ADV and the VR3 interface. Both are well built commercial products
Bad things about the Inspiration
1/ It uses the same 02 sensors that are used in 02 analysers, anyone who has used an o2 analyser will be familiar with how unreliable these things can be, how often they need recalibrating and how much care you have to treat these with. These things are hardly high tech state of the art electronicsNot high tech?, fluid, electrolite interfaces, temperature compensation etc, its okay when you can recalibrate and reanalyse your gas in the diveshop, but when you are underwater, its not quite so easy.
False. It uses a special O2 cell designed just for the buddy (R22D BUD). It even has a teflon sensor face to dispell water from its face
2/ The Inspiration does not have a proper voting logic when deciding what the PO2 in the breathing loop is. The unit has three 02 sensors, it makes its decisions on the PO2 on the "best two out of three".Dont know what you think voting logic is, but thats a pretty good description of it. The Inspiration will ignore the most out sensor. This is so you still get a functional unit if one sensor fails. There are some 2 sensor failure modes but there are test you do if there is anomalous cell readings to determine this
3/ The air in the breathing loop in a rebreather is very moist. The
analysers are in this moist environment on an Inspiration, which is not the best conditions for the analysers to work accurately. The O2 cells get so damp on a dive that often you will see Inspiration divers drying them out between dives. You have to ask why the do this, the answer is "the work better when dry", therefore the cells will give you accurate readings at the begining of the dive, but who knows how good they are after you have been under water for an hour or so. the Sensors are built for that environment and are sealed from moisture and have hydrophobic coatings. The moist air is a bonus. Dont you dry of your torch and computers when your finished diving. The head of the insp has connectors and a solenoid exposed to the moisture. (its designed to be) dying it out is just sensible to prevent corrosion
4/ The electronics in the handsets are unreliable and often fail.Crap, theyre very reliable and double redundant. They fail when hit, or the turtle os stood on them or during transport. They suffer from being on the end of long hoses
5/ 02 sensors should be calibrated across the range of pressures that they are to be used, you can only calibrate them on the surface, you cant calibrate them at depth.You can calibrate them at 100% O2 down to 21% O2. do you need any other range. You can test that they do react to higher O2 levels while on the dive up to 1.6 PP02. Your also calibrating with 3 (or 4 in my case) sensors
There are, no-doubt, many other issues, but these are the main ones that I am familiar with. or not so familiar with as you obviously are not trained on the unit or actually know any details of it
Some people I know who dive them in the UK call them "The Yellow Peril" (after Cato, the mad servant of Inspector Clouseau in the Pink Panther films), Why? Because you never know when its going to strike.
--another--
I cant see how you can say "lets get some facts here", the issues that have been listed regarding the sensors are factual, not just heresay, go and ask anyone who has dived an Inspiration to see how often they have sensor problems, or handset problems. unlike you I belong to the Closed "Inspiration Owners" forum. We are well aware that a few users have some funnies with their units. this is normally attributable to duff sensors or connections. The fact that they are discussing the problems shows that the voting logoc and multiple redundant electronics work
The unit is a life support system, it mixes the gas you breath to a
preset po2, the reliability of that po2 is paramount. If there are
"issues" regarding the units ability to accurately measures this and react accordingly, do you think its a good idea to go and dive on one. The Royal Navy were very happy after extensive testing with the units ability to do this. Should we believe them or a few rumour mongerers
If you compare the design of an Inspiration to a CIS Lunar, or a
Biomarine unit, you will begin to see the difference between a badly designed CCR and a well designed CCR. Yes, some go out of business after selling about 20 units and one is over subscribed and has sold 5000 units. wonder which one most see as they best solution
And thats before you get to the issue of how well trained the people are who are using them. Agreed there is an issue here. There are only about 3 people who should be training on this unit. and I was lucky to learn from one of them. It seems thge world and his dog are Inspiration Instructors after about 10 hours on the thing. This is the big issue
1. The placement of the 3 oxygen sensors is ill-considered. Warm moist
gas which has left the scrubber unit passes over the sensors. This results in condensation on the cell walls which affects the voltage (and hence the measured ppO2) read. External condensation can be mitigated by blowing cold dry diluent over the sensors, but this must be done regularly. There is nothing that can be done about internal condensation.
Correct. ALL CCR rebreathers suffer the same problem. The reason we dry the head is to stop corrosion of the contacts and connectors. The O2 Cell is coated to stop the water affecting it. The moisture in the CCR gas is one of its benefits (no more dry throat after a dive). The sensors need to be in the loop before you breath the gas and downstream of the O2 injector, WHere would you put them?
The implication of this point is that you cannot be sure what the real ppO2 of the loop is. As the ppO2 is controlled electronically, there is significant risk here.
The sensors are just downstream of the injection point for a reason. They do reflect the O2 content well. I have a 4th sensor inserted a bit further downstream from them for my VR3. It agrees very well. Little risk here. The Royal Navy tested the unit extensively and praised the O2 control of the unit. Fact not rumour
2. There are 2 computers driving the unit - master and slave. The idea is that should the master fail, the slave would take control. Both units are driven by the same power source - not too smart.
Not true. Each controller has its own battery. Each is individually load tested at 6 second intervals throughout the dive. Failure of one unit does NOT effect the other
3. Addition of oxygen to the loop is automatic but addition of diluent is not. It requires manual addition and thus the ppO2 in the loop can rise to dangerous levels without any action taking place.
failure of addition of diluent will NOT raise the O2 in any way shape or form. The only time diluent addition is an issue is on the descent and its pretty obvious that you need to add some (ie you cant breath). Most of us fits Auto Diluent addition valves
4. Warnings are via a beeper and the displays. There is some
suggestion that users have been unable to hear the beeper underwater and this has been implicated in some deaths on the unit.
I'm one of the folks that cant hear the beeper on my unit (can hear it on others), I just had to move the sounder further away from my head. Your buddy will hear your beeper and expect you to do something about it. You can also monitor the gauges
There are some other issues more related to CCR's in general. Many Inspiration divers seem to spend an inordinate portion of their dive looking at the handsets to make sure all appears ok. Personally, I think this takes away from the dive. Peronally I think a once a min look at handset is no different from checking on your buddy at correct intervals, its only an issue on your first few dives before it becomes habit, dont you check your guages? You also have to consider the risk to life-support electronics underwater, how they handle differences in ppO2 registered by the cells etc.Dive computers, lights etc , all electronic and all used by most divers
Some users also tend to push their luck in terms of solo diving, not carrying sufficient OC bailout, "improving" the unit with home-made modifications etc. they get what they deserve, in fact this is the category most Inspiration incidents fall into. Improving the unit is fine within reason, The two most common are the ADV and the VR3 interface. Both are well built commercial products
Bad things about the Inspiration
1/ It uses the same 02 sensors that are used in 02 analysers, anyone who has used an o2 analyser will be familiar with how unreliable these things can be, how often they need recalibrating and how much care you have to treat these with. These things are hardly high tech state of the art electronicsNot high tech?, fluid, electrolite interfaces, temperature compensation etc, its okay when you can recalibrate and reanalyse your gas in the diveshop, but when you are underwater, its not quite so easy.
False. It uses a special O2 cell designed just for the buddy (R22D BUD). It even has a teflon sensor face to dispell water from its face
2/ The Inspiration does not have a proper voting logic when deciding what the PO2 in the breathing loop is. The unit has three 02 sensors, it makes its decisions on the PO2 on the "best two out of three".Dont know what you think voting logic is, but thats a pretty good description of it. The Inspiration will ignore the most out sensor. This is so you still get a functional unit if one sensor fails. There are some 2 sensor failure modes but there are test you do if there is anomalous cell readings to determine this
3/ The air in the breathing loop in a rebreather is very moist. The
analysers are in this moist environment on an Inspiration, which is not the best conditions for the analysers to work accurately. The O2 cells get so damp on a dive that often you will see Inspiration divers drying them out between dives. You have to ask why the do this, the answer is "the work better when dry", therefore the cells will give you accurate readings at the begining of the dive, but who knows how good they are after you have been under water for an hour or so. the Sensors are built for that environment and are sealed from moisture and have hydrophobic coatings. The moist air is a bonus. Dont you dry of your torch and computers when your finished diving. The head of the insp has connectors and a solenoid exposed to the moisture. (its designed to be) dying it out is just sensible to prevent corrosion
4/ The electronics in the handsets are unreliable and often fail.Crap, theyre very reliable and double redundant. They fail when hit, or the turtle os stood on them or during transport. They suffer from being on the end of long hoses
5/ 02 sensors should be calibrated across the range of pressures that they are to be used, you can only calibrate them on the surface, you cant calibrate them at depth.You can calibrate them at 100% O2 down to 21% O2. do you need any other range. You can test that they do react to higher O2 levels while on the dive up to 1.6 PP02. Your also calibrating with 3 (or 4 in my case) sensors
There are, no-doubt, many other issues, but these are the main ones that I am familiar with. or not so familiar with as you obviously are not trained on the unit or actually know any details of it
Some people I know who dive them in the UK call them "The Yellow Peril" (after Cato, the mad servant of Inspector Clouseau in the Pink Panther films), Why? Because you never know when its going to strike.
--another--
I cant see how you can say "lets get some facts here", the issues that have been listed regarding the sensors are factual, not just heresay, go and ask anyone who has dived an Inspiration to see how often they have sensor problems, or handset problems. unlike you I belong to the Closed "Inspiration Owners" forum. We are well aware that a few users have some funnies with their units. this is normally attributable to duff sensors or connections. The fact that they are discussing the problems shows that the voting logoc and multiple redundant electronics work
The unit is a life support system, it mixes the gas you breath to a
preset po2, the reliability of that po2 is paramount. If there are
"issues" regarding the units ability to accurately measures this and react accordingly, do you think its a good idea to go and dive on one. The Royal Navy were very happy after extensive testing with the units ability to do this. Should we believe them or a few rumour mongerers
If you compare the design of an Inspiration to a CIS Lunar, or a
Biomarine unit, you will begin to see the difference between a badly designed CCR and a well designed CCR. Yes, some go out of business after selling about 20 units and one is over subscribed and has sold 5000 units. wonder which one most see as they best solution
And thats before you get to the issue of how well trained the people are who are using them. Agreed there is an issue here. There are only about 3 people who should be training on this unit. and I was lucky to learn from one of them. It seems thge world and his dog are Inspiration Instructors after about 10 hours on the thing. This is the big issue
Just reposting some issues from another list to get discussion started....I don't dive a rebreather and don't see the point in diving one unless your diving necessitates use of an RB. I do not see a fit for them in recreational scuba diving given their current technology and track record.
We can argue the technology all day...and you will win because I am ignorant when it comes to rebreather technology since I do not dive one. What I can point out is that regardless of all that wonderful technology people seem to kill themselves with these things with alarming regularity.
Thanks for the link,
Hopefully the cause of death will be posted so if its an eqpt issue it can be looked into, if not nothing good can come from this trajedy
You make good points, but you are over my head on your rebreather knowledge. You should go straighten those guys out on techdiver...
Would love to , but the place is run over by God Irvine and the DIR bigots. These guys give the DIR configuration a bad name. No point in posting facts there, as George will have gone deeper, longer and better. He's already laid into the Inspiration forums over this incident gloating.
That's sad that gloating over the loss of a diver takes place...really pretty sick actually. Anyway, when the use of an RB is necessitated by the dive, I have no problems with their use and see them as a wonderful tool (just not for me). It is the people that dive them just because they are a neat piece of kit that scare me.
{QUOTE}
And thats before you get to the issue of how well trained the people
are who are using them. Agreed there is an issue here. There are only about 3 people who should be training on this unit. and I was lucky to learn from one of them. It seems thge world and his dog are Inspiration Instructors after about 10 hours on the thing. This is the big issue [/B][/QUOTE]
I can't speak for other training agencies(I also teach TDI but they don't endorse the Inspiration in the US at the current time), but I am An ANDI certified Inspiration instructor. ANDI requires at minimum 75-100 hours on the unit depending on prior rebreather experience, and final certification is at the discression of the IT.
In the US Inspiration instructors are few and far between....At this point I have in the neighborhood of 300 hours on unit(with many of the hours in the difficult conditions of the NE US), at least 50 trimix dives on unit(down to 300 fsw), I can teach the first 2 levels, I'll get oked for the final level sometime later this season.. I'm working for my ratings, noone is giving them to me..
Joe
And thats before you get to the issue of how well trained the people
are who are using them. Agreed there is an issue here. There are only about 3 people who should be training on this unit. and I was lucky to learn from one of them. It seems thge world and his dog are Inspiration Instructors after about 10 hours on the thing. This is the big issue [/B][/QUOTE]
I can't speak for other training agencies(I also teach TDI but they don't endorse the Inspiration in the US at the current time), but I am An ANDI certified Inspiration instructor. ANDI requires at minimum 75-100 hours on the unit depending on prior rebreather experience, and final certification is at the discression of the IT.
In the US Inspiration instructors are few and far between....At this point I have in the neighborhood of 300 hours on unit(with many of the hours in the difficult conditions of the NE US), at least 50 trimix dives on unit(down to 300 fsw), I can teach the first 2 levels, I'll get oked for the final level sometime later this season.. I'm working for my ratings, noone is giving them to me..
Joe
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