Anyone experienced with either Azimuth or Dolphin; advice appreciated

[jptrealty]

Hey caveseeker7, is it possible, we agree on something!!!!!! are pigs flying buddy???

All kiding aside you gave very good and ACCURATE advise

Cheers

The pO2 displays have already been replaced. Don't know where the inspection/pre-dive problems come from, first I've heard of it. Neither what "severly compromised scrubber performance" is supposed to mean. From what I understand the coaxial scrubber has less time to complete exhaustion than other designs once the sorb is used up. Jetsam states that in their literature, and it's the main reason for the conservative duration and depth rating.

In all fairness, I've reviewed data on the Steam Machines and a Dräger, covering three different scrubber designs: Annular-axial, radial and axial. Once the absorbing capacity goes, it goes fast. The time/CO2-content curve gets very steep (i.e. they time from 0% to 0.5% is longer than from 0.5% to 1% which is longet than from 1% to 1.5% etc).

 

[Pawel]

Greetings Stefan,

Don't know where the inspection/pre-dive problems come from, first I've heard of it.

C-lungs are entirely encased and not accesible they are difficult to inspect. As Gordon explained to me, the only test you can do is by observing the corrugated hose collapsing/streatching on positive/negative tests. You can't observe or feel the counterlung.
There is also no easy way to inspect c-lungs for water between dives .

Neither what "severly compromised scrubber performance" is supposed to mean. From what I understand the coaxial scrubber has less time to complete exhaustion than other designs once the sorb is used up. Jetsam states that in their literature, and it's the main reason for the conservative duration and depth rating.

In my view the bi-axial scrubber is a mistake. It looks cool, though. Firstly, the gas travel is very long, which has to increase breathing resistance. Most radial scrubbers have about ~5cm gas travel (or huge surface, like MK15/16) and some nice axial scrubbers, like Colkan have also very short gas path and large surface area. Secondly, the shape is suboptimal: convoluted, with "dead corners", narrow and long. Add to it complete lack of insulation (which is inexcusable, IMO) and you end up with perfect recepie for a problem. I am not saying it will happen on a laisury Sunday dive on a tropical reef, that's all fine and good - it will probably last 5-6h, but if you push yourself hard in cold water this thing will go quick, and I mean well before the scrubber rating is up. I would really like to see a 3h CO2 concentration chart in freezing water at 2L CO2/min flow with peaks up to 5L/min. From my experience, I am almost sure it would break through, probably within the first hour.

As to the exhaustion of scrubber's capacity, you are right. The more efficient the scrubber, it will have quicker failure after a longer period when the capacity was exhausted (when it goes, it goes quick). This is not a problem because the failure happens well after the rated duration. I am interested in the failure well before the rated duration is up. This can happen when your CO2 production rate and ventilation are higher than normal (possibly extreme). The scrubber will have plenty of capacity, but limited efficiency to scrub CO2 quickly enough.

The reason I whinge about it is that there is no good reason (other than to sqeeze cost) for such compromised design. I know you guys are sick and tired of me bagging the unit, but in all fairness, I am not bagging Classic KISS or other brands, which, although far from "state of the art", have more reasonable constructions. There are many very nice breathers out there and most of them do not have OMG sticker

My concern is also that, because of Sport KISS affordability, it is likely that it will sell in large numbers to recreational divers, some of which may not recognise this limitation, and the likelyhood of accidents due to scrubber inefficiency is considerable, in my view.

Anyway, I am off to a bunker now before Sport KISS owners and supporters get me

Cheers,

Pawel

 

[caveseeker7]

C-lungs are entirely encased and not accesible they are difficult to inspect.

The entire loop is secured to the case by a single latch. Open the latch, pull the scrubber cannister out, and 100% of the loop's outside area is accessable. It's the best loop access I've ever seen. Opening the latch isn't anymore time consuming or difficult than opening the latch that holds the Azimuth's cover down.
On every other breather I can think of you either have the parts of the loop running through a case, the BCD semi-permanently held by screws to parts of the loop or case.

... the bi-axial scrubber is a mistake. ... the gas travel is very long, which has to increase breathing resistance.

I haven't had one in the water yet, but breathing resistance is reportedly better than several rear mounted CL designs. The length of the loop is but one factor in WOB. The co-axial (not bi-axial) design has two relatively short gas paths through the scrubber bed, with breathing bags in between. That should certainly lower WOB.

Most radial scrubbers have about ~5cm gas travel (or huge surface, like MK15/16) and some nice axial scrubbers, like Colkan have also very short gas path and large surface area.

The annular-axial cannister of the MK series pretty much a radial design laid out flat, and has much the same properties of a radial design.

... if you push yourself hard in cold water this thing will go quick, and I mean well before the scrubber rating is up.

I have yet to see any testing data on the Sport Kiss' performance, and I wager so do you. That means were both guessing.
To be fair I haven't seen any data on the Meg, Classic Kiss or any OMG rebreather either. So I can either believe the claims, or make educated asumptions on their performance based on the general design. I just don't know enough about co-axial scrubber to make an educated guess.

Is there any testing data for a like design that has been published (or made accessable to you) that allow you to be so certain in your assessment?

Look at other general rules:
Two counterlungs increase dwell time and thus scrubber efficiency
Yet two single counterlung rebreathers, the MK15.5/16 and the RB80 (the inner bellows just expells gas & water) seem to be very efficient having repeatedly allowed extreme dives (both depth and time).

Metal is a bad cannister material due to its heat sink properties
OMG and the MK15 use scrubbers entirely made from metal and still perform quite well. The Meg's cannister is made from metal yet it lasts as long as the plastics of the like Inspiration.

Uninsulated scrubbers yada, yada, yada
The RB80 yada, yada, yada
You get the idea. All factors interact, there no absolute here.

I would really like to see a 3h CO2 concentration chart in freezing water at 2L CO2/min flow with peaks up to 5L/min. From my experience, I am almost sure it would break through, probably within the first hour.

Once you're frozen in you won't go anywhere anymore, the wait for spring will outlast any scrubber.

But seriously, I couldn't care less how a scrubber performs at 2 lpm - 5lpm CO2 addition over 3 hrs since it is impossible to sustain. For a human, anyway. What I want is testing done to parameters that reflect real life but at an increased worse case rate (rather than impossible rate). That will give you usable data. If you test at 2 - 5 lpm as you suggest people just gonna say I can exceed that because it can't be achieved. They have been saying and doing that for years with the Buddy.

I am interested in the failure well before the rated duration is up.

That's the problem with some of your arguments and the reason you get so much flak from people:
You're intrested, but you don't really know, yet make claims and accusations.

The reason I whinge about it is that there is no good reason (other than to sqeeze cost) for such compromised design.

Case in point for my last statement.

There are many very nice breathers out there and most of them do not have OMG sticker

The sticker they all have is a price tag much higher than the Sport Kiss. And outside the military that is usually an issue.

I don't think anyone claims the Sport Kiss is the best or the perfect rebreather. Jetsam certainly doesn't.
But it could very well be that it is the best rebreather for what people want to use it for.
Look at yourself. You use an O2 rebreather for some of your work that would be useless to many of us, no matter how well it is designed and build. And it certainly is both of that.

My concern is also that, because of Sport KISS affordability, it is likely that it will sell in large numbers to recreational divers, some of which may not recognise this limitation, and the likelyhood of accidents due to scrubber inefficiency is considerable, in my view.

The limits are clearly stated by Jetsam, and should be taught during training. If someone doesn't understand or recognize them they shouldn't be diving rebreathers. Probably shouldn't be diving at all.

Anyway, save us all by getting the Castoro Explorer (? the mCCR) at a low price.
That looks like one sweet 'breather.

 

[Pawel]

To be fair I haven't seen any data on the Meg, Classic Kiss or any OMG rebreather either. So I can either believe the claims, or make educated asumptions on their performance based on the general design. I just don't know enough about co-axial scrubber to make an educated guess.

Is there any testing data for a like design that has been published (or made accessable to you) that allow you to be so certain in your assessment?

Yes and no. I'll send you a private copy It is not classified, but not for public consumption either.

OMG and the MK15 use scrubbers entirely made from metal and still perform quite well. The Meg's cannister is made from metal yet it lasts as long as the plastics of the like Inspiration.

I am not measuring how long the scrubber will last. This depends only on the volume of the sorb, not the design or insulation! I am measuring the efficiency of scrubbing with high ventilation rates, peak CO2 production and low temps.

Most of OMG scrubbers are not metal. Those that are, are insulated with rubber (including new Azimuth) in addition to double wall construction and gas flow from inside out assuring good insulation and scrubbing performance. MK15/16 have beefy scrubbers. I can't see how you could break through that, even if they were uninsulated. The only criticism is for the o-ring that, if left out, broken, etc.. can cause bad things.

Once you're frozen in you won't go anywhere anymore, the wait for spring will outlast any scrubber.

Maybe I am looking too much from my own perspective. I mostly dive in Sth Australian waters in winter time :xmas_2: . Often I would spend 3+ hours a day on the loop, most of which is at a considerable exercise rate.

But seriously, I couldn't care less how a scrubber performs at 2 lpm - 5lpm CO2 addition over 3 hrs since it is impossible to sustain. For a human, anyway. What I want is testing done to parameters that reflect real life but at an increased worse case rate (rather than impossible rate). That will give you usable data. If you test at 2 - 5 lpm as you suggest people just gonna say I can exceed that because it can't be achieved. They have been saying and doing that for years with the Buddy.

Yes, I have such test results: both simulated and real-life. The real life tests are well and trully "worst case scenario" with three comandos taking turns trying to kill the scrubber within 3 hours. Instead of the scrubber, they exhausted all three comandos consistently ...But the CO2 concentrations and heart rates are quite interesting to analyse.

Anyway, save us all by getting the Castoro Explorer (? the mCCR) at a low price.
That looks like one sweet 'breather.

Okay, back to work...

Cheers,

Pawel

 

[MrConclusion]

I am also looking forward to seeing the price/availability of the Castory Abyss & Explorer. I really like the simplicity of the single chest-mounted counterlung, and the way that all of the breathing hoses are in fromt of, and therefore visible to the diver.

There are some great CCR-modification possibilities for the C-96, but training and certification would not be as easy for a new Rb diver, would they?

 

[Pawel]

There are some great CCR-modification possibilities for the C-96, but training and certification would not be as easy for a new Rb diver, would they?

OMG works with many instructors and most agencies (TDI, IANTD, SSI, etc..). If those rebreathers are offered to public, we will work with them to provide suitable training. In Australia, the usual suspects: Dive, Dive, Dive and Southern Cross Dives and we have some friendly rb instructors in Melbourne and Perth.
If there is demand, most instructors will be interested in teaching the unit (and we would make some financial incentives to make them even more interested), so I don't see it as a problem. We just need to ensure that the units are safe to use first

Cheers,

Pawel
OMG/Apollo Australia

 

[caveseeker7]

I am also looking forward to seeing the price/availability of the Castory Abyss & Explorer.

There are some great CCR-modification possibilities for the C-96, but training and certification would not be as easy for a new Rb diver, would they?

I wouldn't get my hopes up too high as far as the price is concerned.
OMG builds largely military units (which are always expensive), uses high(est) quality materials and does a lot of engineering and testing. Add to that the very high labor costs in Europe and a very week dollar versus the Euro, and neither mixed gas Castoro will be "cheap".

Here in the US training for the C-96 is available through IANTD, and units can be purchased by civilians afaik (though the feds have taken an intrest will know about it).
Dave Sutton has build a neat mixed gas CCR conversion from the C-96, the Minimum Rebreather .
If you go that eay and get both C-96 and KISS training you should be in decent shape.

Thee Castoro Abyss however is more than just a C-96 with cmf valve and a second tank. Considerable changes have been made, including reversal of the gas path. As I said, lots of engineering and testing.

 

[MrConclusion]

Dave Sutton's minimum rebreather is a really appealing machine, in my opinion.

I wasn't thinking that the Castoro Abyss would be cheap, but it'll be interesting to see what the US price tag comes out to when the units are actually availlable. The sales of $10K YBODs (just a joke I actually like them a lot) prove that there is a market for rebreathers with hefty price tags.

 

[caveseeker7]

Dave Sutton's minimum rebreather is a really appealing machine, in my opinion.

I agree, Dave did a great job as he usually does. The concept is appealing, which is why I look forward to the new Castoros. Also, those will likely be CE certified, so you know they've passed some basic testing requirements, even if the details never get published. Which is a shame really, scrubber testing is impressive. Thanks, Pawel.

I wasn't thinking that the Castoro Abyss would be cheap, but it'll be interesting to see what the US price tag comes out to when the units are actually availlable.

One can only hope ... a few years ago the Nemesis e-CCR was shown and praised as the next big thing in rebreathers. The prototype looked intresting, the aimed $5,000 even more so (at a time when new Buddys sold for around $6,200, PRISMs for $7,800 and the then brand new Meg for $7,500). Unfortunately it never materialized on the recreational market, but before it vanished, the price creep went to $6,500.

I tend to be a bit pessimistic when people are running around hailing they'll build an inexpensive, good CCR. Chances are it will be either or, and possibly neither. I believe it when I see it.

The Dive Rite Oh Tooptima was supposed to be the magic $5K unit last October at DEMA. By the time they had decided on a price it was $6.5K for the initial offering, which since, before the first production unit has been delivered to a customer, has been raised to $6.900 ... without O2 sensors, ADV or complete HH deco software.

The sales of $10K YBODs (just a joke I actually like them a lot) prove that there is a market for rebreathers with hefty price tags.

Well, factory refurbished YBODs go for about $5,800, new YBODs for around $7,800 (both with Classic electronics).
Vision-equiped YBODs and BYBODs go for around $10,000
Backlog 8 months in Europe.

The base Megalodon (APEKS) is offered for $7,500, HUD and ADV another $500.
Shearwater deco integrated controller adds $2,000 ... also $10,000
Delivery time between 2 and 3 months last I heard.

PRISM still costs $7,800 as it has been for years (incl. HUD and ADV), the cowling adds about $225 or so. Deco electronics are not yet available. Backlog around 6 months I believe.

So you can get any of the current models for less than $10K, with the exception of build to order MK15.5s or the Ouroboros.
Both of those are way past the magic $10K line. Both are low volume rigs, as has always been the case with prices in that range. The UT240, the MK-5P and previous productions of MK15/15.5 all went to breather heaven. That's the real pain threshold, and builders know it.

 

[KISS57]

Am I missing somethig about the Castoro Abyss and Explorer? They don't apear on the OMG website and I thought they were just mock ups done by Pawel for Oztek. Did they come from OMG or did Pawel make them himself using OMG parts? If Pawel did make them that is some nice tinkering in the shed mate. Kerry and Dave would no doubt be happy that you followed on from their work.

Why was the Nemesis stoped. It lookd good. Not that you should really go CCR shoping on looks though.