Diver one of sixteen to die using high-tech gear
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03-03-2003, 03:24 AM,
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Re:Diver one of sixteen to die using high-tech gear
I am one of the people who have heavily modified my unit. I admit that but thats me (I've done the same to my car ). This is because that original unit is good but not perfect. PS I modified my DV's (detuned) my backplate and harness (extra D rings) and ost of my other dive gear
DRE: There is a small metal screw inside the oxygen sensor compartment, it is located directly across from sensor number two. Condensation often forms on this metal screw and will allow droplets to fall onto the oxygen sensors. This will happen particularly if the diver moves from side to side as in dumping gas from a drysuit or if they invert from horizontal for any reason. Condensation is inherently found within this area and will form on the oxygen sensors even without this metal catalyst. The O2 sensors are located on the inhalation side of the breathing loop, so you have warm gas that just went through the scrubbing process meeting with cooler gas that you will inhale thus the condensation forming on the cell faces. This condensation causes discrepancies/inaccuracies within the cell readings and they begin to VOTE trying to figure out which one is more than .2 bar out of line with the other. Cell warnings will manifest within this period of time and the diver will begin to get audible and visual alarms ...task loading increases. True there is a screw there. But when you are in a normal position the screw is designed to be at the bottom of the area and hence it doesn't matter unless you do the whole dive upside down. The cells are at 90 degrees to each other so any drops can only go on one (where is would run off the Teflon coating instantly) The screw is fully enclosed inside the unit and will be at internal ambient temperature and hence not a condensation seed point. haveing opened my head after many dives there has NEVER been condesation on that screw. I have recently been doing some Ice diving and cold water diving with my unit. This has produced the highest condensation in my unit that I've ever seen (mainly of the metal fittings that penetrate the head). I have had no moisture on the cell faces or even a blip from any cell while on a dive This paragraph is an old quote from George Irvine and was long ago proven to be not true. If a large drop fell on a cell face it would almost certainly be dispelled before affecting the reading, and even if it did, it would generate a cell warning, the user could then decide if this was transient or permanant and terminate the dive if needed. There is 6L a breath of gas rushing past these sensors, they would soon dry off. After all you have metal bits in OC regulators, maybe these are bad as well Not an issue, never been and issue except for those who listen to rumours spread by non Inspiration trained divers who have a monitary and political interest in putting other makes of rebreathers down DRE: The unit alarms if it senses a PO2 over 1.6, which is a good thing. Problem with this is that many of the divers will run 100% oxygen at 20 ft which is a PO2 of 1.6, if they drop below the 20 ft they get an alarm, fair enough. If you have several Inspiration divers in close proximity with cell warning alarms, and high PO2 alarms it becomes very difficult to know if the alarm is coming from your unit or from another diver. Some will be able to assimilate this to being in an area where several cellular phones begin to ring and everyone pulls out their phone to see if it was theirs. Mix this with CCR divers using wrist computers that alarm and you really have an orchestra playing down there, so much for the peace and tranquility of "no bubbles". I have heard the alarm twice in 100 dives!!! (Both cell failures), My VR3 doesn't make a sound. You are over exagerating. DRE: As the diver descends they must equalize the counter lungs, if this procedure is not adhered to and they begin an uncontrolled descent the lungs collapse and the diver is not able to breath, an automatic diluent add is an aftermarket product which does combat this. But since we are talking factory here the diver is faced with equalizing counter lungs, ears, sinuses, mask drysuit, BCD, monitoring PO2 on handsets, buddy position (as far as they dive with buddies), light and depth in the water column. Seems to me like this might be a busy time in which things could move very fast, especially when going wrong. Your out of date. The Inspiration currently comes from the factory with an ADV (Auto Diluent Valve fitted). Manully flying the unit is a piece of cake and only took any brain power for about the first 3 or 4 dives. Yes, if you are manually flying you do need to do the one extra task but its easy. MOST users have fitted a third party ADV (I have) I have added an auto dump as well, so no extra tasks on way down or way up. I'm so taks loaded on my dives, NOT. In fact on thursday I had to do a controlled bouyant lift on a trainee from 35m, guess what, I didn't have to touch any of my kit on the whole ascent. As I dont use my BC for trim, I had my counter lungs and drysuit on autodumps etc. This whole task loading thing is not true, you do have a little more to do when you first start, but by the time you finish your training this is just not true
Diver Mole
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03-03-2003, 04:00 AM,
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Re:Diver one of sixteen to die using high-tech gear
DRE: And since we're at it: weight must be placed on the top of the rebreather in order to balance the trim.
Dont you need to add weight and get the positions of your tanks right when on OC. This is called trim and ALL divers need to do it. One big advantage of a RB is the buoyancy characteristics stay the same throuout the dive, unlike OC which gets lighter as you burn the air DRE: If divers put to much gas in the counter lungs the upper body is lifted and trim is then off center. Yes, but trained divers dont, just like you dont put too much in your drysuit or BC DRE: Gas in a counter lung is just another source to administrate, along with drysuit, BCD, PO2 on handsets, pressure in O2 and DIL cylinders. Can easily be dealt with and with ADV and autodump can be fully automated. Just take the word of someone who does this regularly, it is NOT an issue at all. DRE: The mouthpiece does not have OC bailout built into it, Mine does! DRE:bailout is a time of increased stress so it is pertinent the transition should be smooth without chance for a mistake. True on OC as well DRE: The bailout procedure on the factory unit uses a device called an Auto Air, this duals as a breathing device and BCD inflator. I couldn't imagine this being an effective tool for gas sharing, nor proper bail out for the user either, as the CCR mouthpiece has to be effectively closed before the transition to OC bailout is performed or it will flood the breathing loop making the diver negatively buoyant. Bailout should be in the form of a combination unit on the mouthpiece to facilitate safe transition. Auto air is an OC device!!! and was on sale way before the Inspiration come about. Its the same as an Air 2 and it works. Personally I hate it and removed it fairly early on, but it does work and gives quick and easy access to OC bailout. The argument here is the usual Air 2 V normal OC reg argument and not particularly relevent to RB's Most folks fit a long hose Reg on their diluent and/or carry side slung stage cylinders for bailout. OC/DSV are easily available and I have one fitted. I can go CC to OC in about 1 second and my buddy can also do the switch for me I agree with you that the loop must be closed and that the Inspriation original mouthpiece could do this better (The dragers, azimuths etc have much nicer mechs for this) DRE: If the O-ring on top of the cartridge lid is dirty or not aligned properly CO2 will take the path of least resistance and bypass the carbon dioxide scrubber therefore breathed back into the loop. Hypercapnia begins and the diver is faced with another problem to solve. You are trained to inspect and lube this O ring at each repack. There is a spacer ring that sits on it to prevent it coming out. You do a 3 min pre-breath before each dive to check for this. Not an issue on a dive if you do you dive checks. DRE: The Inspiration does not have SS backplate and utilizes many plastic fastex clips, which I view as failure points. There are seven quick releases on the soft harness including the crotch strap and handset clips. The clips that hold the yellow casing lid on the unit break frequently so spares are required as well. Old GI3 quote and not true. The harness does have the plastic buckles, and there has NEVER been a reported breaking of one of these. APValves are famouse for producing bomb proof kit. A made up issue that just doesn't exist Personally I hated the harness and swapped it for a SS backplate and webbing, so that it was the same as my OC kit. The Insp uses a standard bolt spacing so the options are yours DRE: Scrubber canister is small (2.45 Kg of 8-12 mesh, 797 diving grade sofnolime) and does not facilitate the use many of the mixed gas Inspiration divers put it through. At depth CO2 breakthrough is rapid even with a resting diver, if breathing resistance is elevated the scrubber is near void. With increased CO2 build up the diver is of course exposing oneself to further malady. Diving high helium concentrations assist with this problem as it is less dense than air, easier to breath therefore less CO2 buildup and the scrubber should last longer but it is playing on the edge. High PPN2 should be ultimately avoided. The scrubber has been extensivly tested by third party government test houses to a standard set in Europe (CE). It has a 3 hour duration. If users choose to use it over that, then its their problem. Note than the Azimuth and Drager units have also undergone these tests and are also 3 hour rated. No other unit has been tested to this standard and so figures quoted by the other manufacturers are estimates and not measured. Folks have done 10 hour dives on the Inspiration scrubber (they are mad!!!) DRE: If the counter lungs are not situated adequately they will float above the divers shoulders and increase breathing resistance. It is taught in the basic course to watch for this ... But they are clipped down with fastex buckles which as we know do fail on occasion. With the diver already quite task loaded on the CCR it is easy not to notice the lung has crept up, CO2 will then increase from breathing resistance. No one has ever reported this buckle breaking. The lung placement on the inspiration is superb and as the harness goes through the bas of the lungs if this buckle where left undone the lung would move about 2" which would not effect breathing at all. A imaginary problem that doesn't exist DRE: The LP hoses which feed the diluent and the oxygen inlets on the counter lungs use a different end than the BCD inflator. The BCD is inflated with diluent gas, the same which you are adding into the counter lung, there is no sound reason not to have the same end on this for diversity. The different fitting was for the Auto Air, a normal schrader suit/bc fitting cannot flow enough air for breathing at depth, thats why its different. I have no Auto air on mine and have a standard inflator here DRE: The reason the end is different on the BCD inflator is to supply a greater amount of gas to the Auto Air regulator used as a bailout/inflation device. This Auto Air is prone to free flow situations and can dump the diluent gas if not tended to quick enough. Most Inspirations divers discard this Auto Air early into their CCR career. 44% have thrown it, so the majority keep it. It free flows if the interstage pressure if to high, which you can easily adjust (covered in training and an IP guage comes with the unit). This is an individual choice argument. I binned mine as I considered I had a better way of doing it DRE: If both handsets shut off in the water the diver is faced with a series of questions in order to "reboot" the system. One of the questions ask if you would like to calibrate "yes or no" if the diver is stressed and chooses "yes" they will effectively be adding 100% oxygen into the breathing loop no matter what depth they are at in the water column. WRONG: it is impossible to recalibrate under water, the handsets wont allow it (only the very early units could do this) Why would you turn off both handsets??? On the early uinits, you can actually calibrate underwater safely, you have to tell the unit the correct percentage of O2 in the mix. at 6m this would be 160% DRE: If the battery is low it will not supply enough EMF for the oxygen solenoid to open the valve and add life sustaining gas. Thats why there are double redundant batteries! You can also do it manually if needed DRE: The control handsets are secured to the canister via rubber hose, the wiring is run through this conduit down to the electronic handsets that are monitoring the dynamics of the oxygen sensors. These rubber conduits enter into the scrubber/O2 sensor compartment where it is humid and if not perfectly sealed will allow condensation to migrate into the hose and wreak havoc with the electronics in the handsets. Many electronic problems with the handsets have involved this scenario. What eletrical problems with the handsets?, none reported!!! There have been handsets smashed and cracked. All the electronics are potted in resin so water is not an issue DRE: If anyone feels that there still is misinformation, bad information, unfounded allegations, backstabbing and drive-by-shootings going on, please take it up personally with me. I am. You have done nothing in this post than quote a very old, out of date and untrue post by George Irvine III (Also not Inspiration trained). You are not trained nor have used or probably even seen an Inspiration yet see yourself as an expert and are spreading half truths and rumours about the units as fact. Please download and read the user manuals for several units from the web (check my site for links) and get some real information instead of taking as gospel what you hear on the web
Diver Mole
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03-03-2003, 08:43 AM,
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Re:Diver one of sixteen to die using high-tech gear
Wow, all the way from the UK. Cool. DiverMole, you said that you have experience on several rebreathers, could you tell us why you choose the Buddy? You didn't say whether you have experience with both SCR and CCR. Could you tell us why you choose CCR? I understand those are personal choices, but if people here could hear WHY you made those choices I think it would add greatly to the thread.
Thanks T
Safety first, ego last, actions speak louder than words or c-cards.
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03-03-2003, 09:08 AM,
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Re:Diver one of sixteen to die using high-tech gear
By law only CE certified rebreather are allowed to be sold in Europe so that limited my choice to Dolphin, Azimuth and Inspiration
Tried Dolphin and it dug in my back!!!, plus the SCR's were too limited in what they could do. I regularly dive beyong their capability in deoth (and now duration) Also when I looked into it the skills on CCR seemed only a little more than SCR Also lots of CCR owners are ex SCR owners, not aware of anyone who's gone the other way. If your going to end up there, might as well start there. I've been helping Dave Thompson teach a few Azimuth and Dolphin classes since. I'm certain I made the right call. Inspiration is almost as simple and easier to set up than azimuth and safer than the jet blocking Dolphin
Diver Mole
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03-03-2003, 09:26 AM,
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Re:Diver one of sixteen to die using high-tech gear
DiverMole- I'm curious: how did you find your way over to a Minnesota scuba forum? If I missed this in an earlier post, just point me in the right direction.
"Treat people as if they were what they ought to be and you help them to become what they are capable of being." - Johann W. von Goethe
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03-03-2003, 09:28 AM,
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Re:Diver one of sixteen to die using high-tech gear
Hi First of all i would like to introduce myself to the group.
My name is Laurence, i live in the UK and i have been diving for 12 years and i am a PADI MSDT and also well experienced in Advanced and Extended range diving, i have no experience of Trimix diving. I have dived for over a year on the Drager Dolphin SCR and from March of last year the Inspiration CCR. I think both units are great and both have good and bad points. I have been following this thread with interest and you all seem to be open minded people with a genuine interest, there are good and bad things with the unit, with every Rebreather. The Inspiration and Rebreathers in general are not for everyone and i dont believe in trying to tell someone that they should get one when there not interested. I notice DRE that you are the Moderator, and you run a great site, i have no problems with people who want to critisise the Inspiration, as long as that critisism is based upon fact and knowledge. Im not talking about whether you have dived one or not, that makes very little difference, but if you are going to make an argument against the unit, which is fine, you should try to use your own words. With almost every statement you have use to reply to Madmole, you have used somebody elses words. Words which were refuted a long time ago and proved inaccurate. How can your argument be given credence when you use other peoples thoughts. Just my 2 cents worth. Right, i have my fire proof trousers on and my Rebreather as my BC set. Flame Away. All the best. |
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03-03-2003, 09:35 AM,
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Re:Diver one of sixteen to die using high-tech gear
I think the worldwide CCR vs. OC debate train just stopped at the mnscuba.com station. Welcome to the forum gents!
--Jason
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03-03-2003, 09:42 AM,
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Re:Diver one of sixteen to die using high-tech gear
So DiverMole do you think that all the problems with the Buddy have been fixed either at the factory or with addons or are there still some problems? This gets back to the original reason of this entire thread. Are some people just being stupid and dying or are there inherent problems and people are dying? The first reason is just Darwinian and fine by me, the second is what I am concerned with.
T
Safety first, ego last, actions speak louder than words or c-cards.
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03-03-2003, 09:43 AM,
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Re:Diver one of sixteen to die using high-tech gear
Divermole,
I asked George if I could use his article and he was fine with that. I'm glad someone finally was able some of the questions I had regarding the Buddy's design, and it seems they changed quite a bit from when the unit first hit the market. I don't have to be a rebreather diver to form an opinion about them - I don't even need to know per se all the technical details involved with the unit (although I did do my homework)to know that they're extremely dangerous to use, the chances something might go wrong a lot higher, and the dives itself a lot more complicated than on OC. What you do in your spare time that's up to you. I've tried to gather as much info as possible - it always seemed though that when I approached certain rebreather divers with critical though warranted questions regarding their units and diving styles, they got so defensive no reasoned arguments either pro or con followed (hence the backstabbing remark, which refered to something going on behind the scenes). At least you took the time to go over everything in detail and explain yourself rationally - must be the distance thing... I thought it was interesting you brought up the fact that in your diving you've come at a point that CCR's are the only way to go in terms of gas management. If you wouldn't mind sharing some of the details of those dives and how you calculate them in terms of gas management that would be very informative. Nobody locally wanted to answer any of my questions regarding gas management, bailout procedures, etc. so maybe you could step up and share your info. I would also like to suggest the administrators to ask you to become the new rebreather section moderator. |
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03-03-2003, 10:22 AM,
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Re:Diver one of sixteen to die using high-tech gear
Hello to list,
I own both a Dolphin SCR and Inspiration CCR. Both have advantages and disadvantages. I would compare them as the SCR is more for recreational diving and the CCR is more for technical diving. That is a generalization and how each is used and how safe they are depends upon your training and how you apply the training. I prefer the Inspiration as it offers more options to emergency situations and can be used with mixed gas technical diving. It is truly a deep diving rig. It is also a technical machine that requires training and discipline. Diving the Dolphin is like driving a car whereas the Inspiration is more like flying an airplane. The Inspiration requires more training and more pre-dive checks. I love rebreathers for the silence, warm moist air and near ambient breathing at depth. I only use open circuit with students or when there is no way to use a rebreather. Traveling with a rebreather does add weight and gas and scrub is not always available but things are improving and will continue to improve. Rebreathers are not for everyone and deciding to move to a rebreather is a personal choice. Personally, I like the challenge and as life itself is a risk, I am willing to do the training and practice that is required to dive a rebreather in a safe method. This choice however should be based on fact and from experience. If you don't like dive planning, equipment maintenance, emergency drills then just stay with open circuit as it is much easier. As for me, I love rebreathers and believe it is the future of diving. For now rebreathers should only be used by people whom are willing to commit to the training and discipline it requires. Once trained diving on a rebreather is a breeze and I really dislike OC in comparison. Dive on! |
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