My very first rebreather...

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

MikeR once bubbled...
Whoa,

I was a bit slow on that. Your unit assembly should have been a joint effort with very descriptive instructions and verification and re-verification of assembly. You assembled this alone? That should not have happened. Madmole is absolutely correct. After 1 co2 episode the unit should have been stripped down and the problem found and resolved. End of Story.

Hi Mike:

I did not assemble the unit alone. Jeff was always there and whenever something did not make perfect sense, I asked questions. And Jeff checked my work. This one piece did fall through the proverbial crack, and that is unfortunate. All other areas of assembly went correctly (often after a trip to Steam Machines :) ). The carbon dioxide issue will be in my next post.

Thanks for your note.

Todd.
 
pwfletcher once bubbled...


Your fault? It is the instructor's responsibility to make sure that you assemble the rig correctly. After all, that is what you are paying him for. If you had have died and it was later discovered that your rig was put together incorrrectly in a class, I guarantee that he would have been held legally responsible.

Hello:

Thanks. And I do agree. It should not have happened. The real world is far from a perfect place, and things happen from time to time, no matter how diligent the efforts involved, no matter what may be at stake (e.g., NASA). I can look back and understand the exact chain of events that occurred; unfortunately, not everything is foreseeable.

As far as liability is concerned, I signed a waiver which included everything from bathroom breaks (kidding) to gross negligence (which I am *not* implying). I have always believed that you should understand the document that you are signing and if you are not willing to accept the terms therein, you should walk away. Waivers exist for a very specific reason.

Thanks again.

Todd.
 
caveseeker7 once bubbled...

In all fairness, so far I've only heard one side of the story, and not quite as detailed as I would like. Before I decide for or against anyone or -thing I always try to get both sides of it.

Even Todd wasn't entirely unhappy with the training, so the detailed story might come across a bit different. He knows it, after all. You guys paint him like a moron, which I doubt he is, and that's not fair to either him or Jeff. I for one appreciate Todd's report, and hope he clears a few things up and stays here.

These are very well reasoned sentiments, irrespective of my potential level of moronality :) . Is too a word. I have heard Jeff's "side" of the story. I accept it. I did not write about my experiences so that Jeff would come off badly or that I was somehow wronged. In fact, I *tried* to write my class report attempting, and failing, to minimize those exact points while still sharing my actual experiences. I have learned so much at ScubaBoard. I know that there will be some folks who might be interested in rebreathers that read through all of these posts, as I did, to gain some information or insight. I just tried to write what happened to me so that others might take away a few examples of what not to do :) .

caveseeker7 once bubbled...
I'm also a bit suprised that while y'all tearing up Todd and Jeff nobody's mentioned the seller of the rig. You Hammerheads don't wanna upset the big Kahuna? KJ sold the rig, he services MKs, and is an instructor for them.

I wonder why bits and pieces were missing, the rig undivable.
Todd, did the rig come with a list of parts to be replaced? Where you aware how many of them were missing or in unusable condition? Or were you left with the impression that this was a new rig with some dust on it ... ?
Makes wonder how the two other divers and their rigs did. And while I'm usually more intrested in Prisms than MKs, in this case I'm more curious about the 15.5 as it is closer to Todd's.

Kevin gets off unharmed. He sold me the unit and told me about its exact condition. The missing piece is actually a giant rubber band, which was included in with the unit. Kevin told me that many Mk-15 divers used electrical tape instead of the rubber band. I just put the electrical tape in the wrong place :) . Duh. If I had it to do over again, I would have paid Kevin to completely service the rig before shipping it to me. The reality is that it *is* a new rig with some dust on it–some of the parts just sat a bit too long in the case.

The other two divers did great in the class, neither having any problems whatsoever. The Mk-15.5 diver had a completely different scrubber, so he did not face the issues that I did.

caveseeker7 once bubbled...
How long before you noticed, how severe where the symptoms, how long to recover? Where you the only one realizing you got hit while still UW?
Was it caused by the same missing/missassembled/damaged part both times?
So am I. How long before you noticed, how severe where the symptoms, how long to recover? Where you the only one realizing you got hit while still UW?
Was it caused by the same missing/missassembled/damaged part both times?

The general story:

By the time we got to the pool, I was a giant ball of stress. Every, single day was both long and intense. I was delaying the other two students from getting in the pool, and felt quite badly about that. There were parts issues, as in if I, or, more accurately, Peter, could not locate a certain part then I would not be able to participate in the class at all.

Another factor in all this is everything that I have heard and read about the breathing resistance of the Mk-15 (not good). So, I am a stressed diver who thinks his rebreather likely breathes like a pig, especially with the Scott (original) mouthpiece.

Given these two parameters, what happened in the pool could make sense in a way that is unrelated to carbon dioxide buildup. I was stressed in the water. I found the unit hard to breathe. It does make some sense. I was not in any pain nor did I experience any headaches as we were in the pool, and if I got "stressed" or found the unit "hard to breathe," then I just popped up. I typically would stay down about six to eight minutes at a time in the pool.

The first open water dive did not go well, but in a sense it went better than the pool. I stayed down twenty minutes before calling the dive, thanks in large part to that leaky mask :) . I did not feel great coming out of the water but the scrubber, as it would just have to be, was on the last dive before its scheduled change. Hey, things went better, might have had a little break through at the end. I said these things, Given the circumstances, it all made sense.

The next day, a new scrubber, and a very unpleasant dive. I called it. I had a headache. I was angry at everything. At this point carbon dioxide was the obvious culprit. I went back to the dive shop and followed the path of the gas, and realized where bad things were happening.

It was always the same part. The worst headache went away in a little over a hour. And I was the only one who noticed underwater.

By the way, the unit now breathes quite nicely, thank you.

Todd.
 
Hiya Joe:

padiscubapro once bubbled...

EVen new units fail out of the box.. The unit has to be inspected regardless of its age.. Buying a rig like a MK 15 I would have expected atleast a day tearing apart and rebuilding the unit.. I am not a MK 15 diver but I do know the complexity of them.. Rebuild and teardown is part of the class.. Individual days should have been scheduled for both the prims diver and yourself. The actual diving and pool work and most of teh academics can easily be shared. The breakdown really can not..

Everyone seemed to have a different idea of who should be responsible for the large-scale overhaul, or at least I got that impression during the relevant conversations.

padiscubapro once bubbled...

I wasn't trying to criticize your instructor.. You have spoken to me in person and on the phone and you know how I feel about training issues.. Money and time should not be a factor, safe and complete training is the goal..

Joe, I think this is my reality. I really like Jeff. I think that he is a great person. And I have no interest in criticizing Jeff or, for that matter, anyone else. I am a beginner. I have no idea what someone should or should not have noticed. I took the class, I reported what happened, and I have been very interested in what y'all (I try to be pseudo-Texan once a week) have had to say. I just don't know what to say anymore...

padiscubapro once bubbled...

My criticism was that you complianed about being difficult to breathe and you couldn't stay on the loop.. Being told that the breathing resistance is higher than OTS rigs (which is true) wouldn't have made it hard for you to stay on the loop..

It surely was difficult to stay on the loop :) .

padiscubapro once bubbled...
I don't know if you had rapid breathing (you probably did), I wasn't told if you had any chest pains (probably). But this should have been covered in academics about CO2 symptoms..


I don't know if I would say rapid breathing as much as shortness of breath. The difference could very well be my semantics. I didn't have any chest pains, but I did have some general discomfort. And, yep, all this was covered in the academic portion of the show.

padiscubapro once bubbled...

Also once in the water your motor control skills should have been degraded somewhat and is usually visable to other divers, and if they know what to look for its clear as day..

I did feel as though my motor control skills were compromised. I also found it a bit hard to concentrate.

padiscubapro once bubbled...

I am glad you got alot out of this learning experience, but my problem is that CO2 "hits" are serious.. You are lucky you didn't pass out.

I think that I only know what did happen to me, not what could have happened to me...

padiscubapro once bubbled...

I tried to keep my previous responses short and not bash someone where I had only one persons recollection, and just state facts as I was told but now I find myself defending my criticism..
If even one of the above is true its the responsibility of the instructor to prevent when possible and correct it immediately..

Joe, I hope that you did not think that I was being critical of anything that you wrote in any way whatsoever. It simply is not true.

Thank you as always for your comments and insights.

Todd.
 
Hi Todd,

Sorry your getting beat up a bit. Granted we dont know the entire situation, but via your description there are a few issues. As an instructor when a student brings a unit to me for instruction (by all rights your unit should have gone directly to your instructor) it is my responsibility to verify integrity and operation of the unit. Given your circumstances and the age of the unit involved I would have been inclined to repair and refurbish the unit prior to your arrival. I also believe a unit under those circumstances should have been dove by the instructor prior to your arrival to class. Not badmouthing anyone, but the units divability and function shifts from the seller/manufaturer to the instructor once instruction begins. On an older inactive unit alot of flags should have gone up. Anyway be careful and I hope the second trip goes better:).
 
Todd,

All the arguments above are relevant and should be taken to heart. But I wont beat that horse anymore:)

1.) Something to think about. Your unit had never been dove. So at some point in time it was probably prepared for storage. The entire pnematic system must be removed disassembled inspected and cleaned. I've seen them completely disassemled and all parts completely coated in a preservative and reassembled. Any residuals of these chemicals would not have a good effect on your body. Remember if you see any red on the connections it needs to be tightened. For complete disassembly a camera is your friend.

2.) The all cells must be new (your should not have had any if properly stored).

3.) The electronics must me completely gone through and connections verified and reverified. I personally would get an updated set of electronics. You should have 1 anaog and L101H display.

4.)Throw away the naural rubber seal in the scrubber and replace it with a truck tire innertube. Not pretty but works much better than the original. Again while I was not there I suspect this is the peice you were missing "cannister seal" and was causing you grief later on. You should replace this on a contnous basis. I make a new one everymonth, but would do it at least every other month. We all know the effect chemicals have on rubber, better safe than sorry.

5.) the spheres are very fragile. Never hot fill them. The need to be fully submerged in water and filled very, very slowly. I generally never fill mine past 2500. Never drop them! If you do you need to inspect for cracks as this happens often and easily.

6.)Always do your pos/neg tests and prebreathe the unit for at least 5 preferably 10 mins before diving. Not working (sitting on a boat) it takes longer for CO2 to become evident. I generally feel pretty good about my unit with a 10 min breathe. I have had problems in the past and they have showed themselves in this time frame.

7.)Never trust it:) And enjoy diving it:D. It wall always require a fair amount of tinkering but is a good unit. Once you get the bugs out you should be very happy. Take 1 seriously. You can only imagine what a guy who does not dive these when given the task of prepping it for storage may have used.
 
One thing that this thread does bring up is the need for a cost effective C02 monitor for rebreathers. We have at least double and sometimes triple redundancy for everything else such as gas supply (oc bailout on diluent and sling bottles), PO2 monitoring devices (two sets of electronics and three O2 sensors on the inspiration), backup power supply (separate batteries on the inspiration and analog backup on the prism). It seems like CO2 monitoring is the last piece of the puzzle ... especially since CO2 problems are difficult to detect and there is little time to react once you do experience the symptoms.

What can we do?
 
Todd,
thanks for the long and detailed posts.
While I agree with the rest of the board that your fault in this case was not entirely yours, considering you're just starting out, I find it very refreshing that you're willing to take responsibility for it.

In '97 Richard Pyle made a pretty harsh and eye-opening post, that centered around his motto
****************************************************
" WHATEVER happens to you when you willingly go underwater is
COMPLETELY and ENTIRELY your own responsibility!
If you cannot accept that responsibility, stay out of the water!"
****************************************************
I have to agree with him, and it seems you take that responsibility. It says a lot about you and your state of mind.
I wish you good luck with the remainder of your training,
dive safe.


Saturated,
do you use the Tavco steel spheres or the Inconels? Are they equally fragile?
I thought the Tavcos were a bit sturdier.
Which electronics do you have in our MK?


PW,
build 'Twinspirations', or RB Twin80s?
Seems the only thing we can do at the moment ... :(
I still hope that eventually something better than chemical absorbant will be developed ... molecular sieve, something like that. Hydrophobic, non-caustic, smaller in size so we can get redundancy without the bulk and expense ...
Dreeeeeeam, dream, dream, dream ... :rolleyes:
 
Caveseeker,

I have Biomarine electronics. I originally had the "O" but have the revision "G" Electronics. Next time I have even the smallest issue Jurgenson (spelling?) will be getting some business from me . My suggestion is that if Todd is having problems I would consider updating to their setup as well. Might be cheaper than band-aids over the long haul.

I hove both sets of spheres. I asume that by the age of Todd's he has the "more fragile" inconel spheres. I'm also guesing but he probably has a revision "O" electronics. The tavco cylinders are a definate improvement, but I would still be dilligent in my inspections and care. Slooooooow, cool filling should be the standard. No reason to take any chances with either model.
Just MHO.
 
https://www.shearwater.com/products/swift/

Back
Top Bottom