TDI Inspiration Course Report

[Skeletor]

Well, I am now fully qualified to dive an Inspiration Rebreather to a maximum depth of 40m. Will I dive to 40m on it ? Will I b******! well, not for a while anyway.

My partner in crime for the duration of the course was none other than my original PADI open water instructor, Chris. With over 15 years of open circuit experience, he had decided that it was time to find out what these new fangled rebreather thingies were all about.

The course started off easily enough with a brief history of rebreather technology, followed by a review of the various different types of rebreather currently available. This inevitably lead to a discussion on just how the hell a KISS works, followed by a general agreement that none of us really have a scoobies, and that regardless of this, we have made the right decision by buying Inspirations. Lets be honest, after forking out the best part of £4.5K, you wouldn’t really expect us to arrive at any other conclusion would you.

The physics and physiology was simple enough, and little more than a review of the advanced nitrox course. Next came the fault conditions and responses required. Now, for anyone contemplating doing this course, a little tip; if the question begins with What do you do if . . . . . . , the answer is ‘bail out’. There are many other ways of dealing with a problem, but for the purposes of the basic mod 1 course, the emphasis is on bailing out and only then considering sorting the problem. This differs from the mod 2 (trimix) course, where I am reliably informed, bail out should be the last option and you should stay on the loop for as long as is safe.

A bit more detail on dive planning and NDC limits using constant ppO2 and we were then onto the ‘workshop’ session.

Prior to this, my new unit had been sitting in its packing crate having arrived from AP that morning. The theory session had been an exercise in restraint simply because I was desperate to open the box and have a fondle.

After a couple of hours being shown how to dismantle, re-assemble and maintain the units, we were ready for a wet.

The first dive was a bit of an eye opener. Having done a try dive on a unit a few weeks earlier, and having a few OC dives under my belt, I expected that I would be reasonably competent. Any such thoughts were banished after 10 minutes into the dive, I broke the surface following a ‘brisk’ ascent. I wouldn’t exactly call it rapid, but it was quick enough to scare the crap out of the duck that I surfaced under. Now I suppose my first thought should have been to ensure positive buoyancy and then check the handsets. My actual response was to have a quick shufty to make sure no one on the side had noticed, but any hope of going unnoticed were soon dispelled when the aforementioned duck launched a full on assault on my face.

After fending off psycho duck, I waited patiently for my instructor to surface, but after a few moments, the realisation dawned that I was no longer an OW student, and at this level, he was waiting for me at 6m to sort my shit out and rejoin the course.

One thing that I did notice is the very occasional urge to switch to open circuit to get a breath of ‘ fresh air’ I have seen open water students try and head for the surface for this, but thankfully that reaction has long passed, but now the alternative seems, subconsciously, to be to take a breath on an OC reg. Gradually throughout the course this urge seemed to die down, I suspect that this was to do with getting used to breathing warm air, and my subconscious association with this to ‘stale’ air. I don’t think that the fact that it was 29 degrees on the surface, and that even underwater I was hot, helped.

Bouyancy continued to be an issue throughout the first dive, but steadily improved as I began swimming around objects rather than over then, and as I became more proficient at dumping air from the loop.

Any hope that I could make life easier for myself by having the ADV fitted were soon quashed when my instructor fitted his own flowstop upstream of the ADV and turned it off. The first few times that you bottom out the counter lungs is a bit of an unnerving experience and sees you scrabbling for the manual dill injection with whatever hand is nearest. Chris, who after 15 years on OC, tended to associate the experience with emptying a cylinder seemed to have developed the urge to bailout to OC whenever this happened. When I was given back my ADV on dive 4, I had become so used to manually injecting that I actually continued to do this for the remaining dives, manually adding air into the loop just before the ADV kicked in. The ADV is in my opinion, a great addition that means you can draw air if for some bizarre reason you cannot manually inject, and is fine when you have half a lung full, but when you have almost full lungs and then the counterlungs bottom out, due to the cracking pressure, it’s a bit like trying to breathe a McDonalds milkshake.

The emphasis on all of the open water dives is, fairly predictably, practice, practice and a bit more practice. Mouthpiece removals, bailouts and dilluent flushes were carried out several times on each dive until they became instinctive. Of the 6 hours of dives, I must have spent at least 3 hours manually flying the unit, either using the O2 injector to maintain the pO2 simulating a solenoid failing closed, using the O2 cylinder valve manually to simulate failed open solenoid valve, running the unit as a semi closed rebreather or running it as a pure oxygen rebreather above 6m. Other skills included shutting down the O2 valve, purging the loop and then reopening to try and drive a failed solenoid back onto its seat, mask removals without the aid of the ADV and SMB deployment (for which on a CCR, and in my opinion, a crack bottle is the ‘must have’).

During dives 5 and 6, the instructor continually pulled out flashcards indicating spurious cell readouts or other symptoms, such as increased breathing resistance in the loop to assess our response to a random problem.

Halfway through dive 5, my unit appeared to develop a genuine problem. The solenoid was opening, but it did not appear to be injecting O2 quick enough to maintain the required pO2 in the loop. It was never slow enough that the pO2 dropped to a dangerous level, but on a longer or deeper dive, it would have been sufficient to seriously effect your deco requirements. A complete strip down and rebuild could not reveal the cause of the problem, so on dive 6, I swapped electrics with my instructor to see if the problem reoccurred on either his or my unit. This would at least narrow it down to either the head unit, or the O2 first stage. Sods law ruled that the same problem did not happen, so the cause of the problem is still not known, although half way through the O2 creped up well above the set point on my instructors unit to the point where he had to bail out. At this point I had already ripped out my own off board OC reg just in case of the unlikely situation where my instructor might need it, its one thing a student being in the shit, but the instructor is just not on.
A phone call to AP is now in order to try and establish why this is happening.

The events of dives 5 and 6 have left me feeling a little unnerved. Although I have been shown the skills required to deal with the problem, it has acted as an effective reminder of the units ability to f*** up at the least appropriate time. In some respects, I would say that this is a good lesson and will certainly help me not to become complacent during the ’honeymoon period’.
I now work on the presumption that the unit will try and kill me, it is up to me to pay attention to what the unit is doing and thereby realise this before the problem becomes unmanageable. This is not meant to sound all macho, staring in the face of death, type crap by the way, if I really thought the unit was dangerous, I wouldn’t go near it. But whilst the problems on a rebreather, in most cases, tend to give fair warning, they are very insidious, so this attitude is simply about ensuring that I understand the warnings and act in sufficient time. Its no good just glancing at your handsets every once in a while, you must understand what they are telling you. Sounds obvious, but it wasn’t until about dive 5 that I really started to comprehend this. It is very easy to get swept up in the course because there are a lot of practical skills to learn and during the first few dives, you may think that you have listened, and you may be able to carry out the skills when prompted, but there is a huge gulf between this and actually being able to react to real problem.

So, do I feel that I can dive safely on the unit ? Yes. I have sufficient value for my life not to try and kid myself otherwise, but, as I said at the start, there is no way that I am going anywhere near the limits of my qualification for a long while yet. I have so much still to learn and I Intend to leave myself a big margin for error. Its going to be a long time before I can really start to relax and enjoy the dive, at the moment about 80% of my attention is devoted to the unit and the other 20% to where the hell in Stoney / Dosthill I am. I had been planning to dive the JEL and Scylla next weekend, but that’s now binned as I just don’t feel as though I would be able to devote enough of my attention to the wreck to do it justice (even the Scylla).

Am I still happy that I brought an Inspiration ? Well, in the short term, I am going to miss out on some good dives, but in the long term the answer has to be yes, the Inspiration is a great bit of kit, but not without its quirks. The reason I went down this route in the first place was so I could use trimix in the 35 to 60m range, and the inspiration suddenly makes this a viable alternative to OC trimix of deep air (which is really not my bag).
But, I guess the moral of this, for me anyway, is that this is not just a big investment of money, but is also a big investment in time and effort. I have a long, long way to go before mod 2.

ATB,

John

[Crisspy Fiver]

Nice write up John.

It would be nice to read how you progress and grow with the unit as well. So do keep us updated.

Make sure you take care as well. As you say take your time. The wrecks are not going any place.

Iv not done nearly enough dives to be able to think about getting a rebreather, maybe one day........

Jamie

[Juz]

Agree with Jamie - a nice report, especially as I'm thinking of this route myself very very soon.

Cheers
Juz

[Padowan]

Great report. I do my course in 2 weeks, so have read it with particular interest.

[dalegray]

Good Report.

I did my course earlier this year in Menorca, and have just rebuilt my unit to a spec I like, I swoped the wing, put a proper OC bail out on (ditched the Auto Air), added more weight to the unit so I can stay with the same size weight belt I use on OC, added a pony cylinder to the side as I dive quite alot with OC divers and my bail out is for me not them.

I am glad I did it, but as you say it does take alot of getting used to.

Back to Menorca in October to do Mod2

[Andrew H]

The more I read about CCR the more disillusioned I become. They seem to deliver fantastic benefits at fantastic prices but also fantastic risk and complication. I recently read Richard Pyle's comments on his reabreather diving and found much the same story there. Not only does it take you back to square one but it seem to be worse than that. Don't get me worng I still want one, I just feel that the dream is letting me down. Must be a gap in the rebreather market for the product which I thought the inspiration was!

Andrew

[dalegray]

The thing most people forget about the inspiration, is that it is a budget model, the British Navy Re-breathers cost in the region of £50,000 each. I haven't dived on one but at that price I would expect it to work perfectly, As I paid less than 1/10th of that figure, I accept that there will be less than ideal features

As a budget model it features items that people, used to the best OC equipment money can buy, find substanded.

The most obvious item being an AutoAir, followed closley by the wing and harness. These are changable, but it is best to change them after you have had some experiance on the standard unit, so you know why you are changing an item.

If you are not confident enough underwater to accept the problems this method involves, then stay on Open Circuit until you are, no matter how long it may be.

If you are a confident diver, then I would recomend swopping to Closed Circuit, it continues the learning curve, has advantages in gas usage and deco times, and its a shiny new piece of kit. And as an added bonus, it keeps you on your toes by trying to kill you occasionaly.

Yes I do consider that last point an advantage. If you don't then don't buy one.

[Mark Chase]

Top report. I realy enjoyed reading about your experiance and feelings. I am looking into CCR at the moment so this thread on the YBOD and the KISS thread should make very interesting reading.

Please keep the updates coming

ATB

Mark Chase

[BrianG]

A great report, which gets across the dilemma we all have after such a large investment on a single item of kit and the realisation of the higher level of involvement required above and below the water.
You are absolutely right to take things slowly and build up your experience one step at a time. Had my unit developed a fault during the course I would have been thoroughly put out. Well done for staying with it but I can understand how it shakes your confidence. The back up from AP is first rate they will sort out the problem for you I am sure.
I advise strongly that during your work up dives you dive with a buddy using the same unit, if at all possible. As you indicated in your report it is one thing to know the drills but an entirely different matter to diagnose a problem and react accordingly during a dive. Two heads are better than one, and although the unit can bite you hard you normally have a reasonable time to sort out the problem and even confer with your buddy if necessary.
I am sure after 30 to 40 hours on the unit you will be far more relaxed and doing the 40 metre dives with confidence. No air consumption problems, plenty of bottom time to relax and enjoy the dive, and the minimum of deco to complete. Thats when you realise why you invested in the unit and hopefully like me know there is no way back.

Keep us informed of your progress and good diving.

[Andrew H]

Woohoo! An anonymous red dot! Now I feel like I belong!

Come back flame wars all is forgiven!

Andrew