Anyone experienced with either Azimuth or Dolphin; advice appreciated

[MrConclusion]

Caveseeker7 - You have definitely given me something to think about, as I have read about the KISS principle but didn't realize how much cheaper it was compared to something like a Prizm, Megalodon, or Inspiration. I would murder a lot of O2 sensors with age instead of heavy use, but I see that teledynes are available for about $70, so perhaps this is not so completely terrible.

Would I not alse more or less instantly need to get something like a (pricey!) VR3 to calculate my NDL and/or Deco? With the PPO2 not being constant throughout the dive, is pre-planning software even an option?

Yeah, I agree that my current equipment is not perfect, but I am relatively comfortable as I never dive solo deeper than 2x my freedive ability, which seems like an old-school but completely sensible way to go. When I said I had practiced an 80' solo emergency ascent with the dreaded spare air - that was the ONLY time I went down that far alone, and it was only for that test! I generally stay above 50'.

In fact, this whole plan for a rebreather has come about because I was planning on getting a set of doubles, but the airlines are becoming ridiculous about tanks! I was thinking that in the worst case, i could get a "modular" rebreather and use local tanks, or get a rebreather that uses small tanks and ship them ahead of time by DHL if worse comes to worse.

Asking questions trying to make up my mind... and now I have even more decisions to make!

Again THANK YOU EVERYBODY this is a great forum.

 

[MrConclusion]

Do any rebreather divers ever "meet up" in the caribbean, florida, etc. for diving? I will be the only person I know using an RB, so it looks like I'm going to need to make some new friends who have some exerience!

(Hey, I brew beer for a living so at least I'm useful at :59: after-dive parties!)

 

[Pawel]

Hi Stefan,

Let me debate some of your points

The gas addition is not unlike active-addition SCRs you asked about. An orifieced valve bleeds O2 into the loop continiously. The SCRs inject considerably more gas than you need (most of the time, anyway, they can be "overbreathed") ...

"overbreathed" - Do you mean just like a mechanical CCR such as KISS?

I would not dive either active-addition SCR without O2 monitor, so there isn't that much difference in that respect for between SCR and CCR. Other than the O2 monitor the KISSes don't have electronics, so any worries about those don't apply.

Not quite, in a CCR the only way to know PPO2 is to measure it (unless you are on pure O2), whilst a SCR, when operating correctly, will have predictable PPO2 depending on the depth and mix. PPO2 meter is not necessary for SCR operation and there are different designs and features that allow you to verify the unit is functioning correctly (within liveable PPO2). On the other hand, the safety diving a CCR relies 100% on a PPO2 meter. A dead batery, bad sensor = no diving, period. In a SCR a PPO2 meter is "only" an additional safety feature. Therefore, all things being equal, a CCR would offer a significantly higher risk of hypoxia than an SCR. Hyperoxia is not even possible in an SCR within diving limits! A simple single-cell PPO2 meter is more than adequate for an SCR and is optional. A CCR requires (more expensive and complex) multi-cell PPO2 meters. So, I agree to differ with you on that one

The SportKiss also includes an OC second stage integrated into the DSV, a quarter turn to close the loop and you're breathing of the 2nd stage. Beats both Dräger and OMG DSVs.

It certainly does with weight and jaw fatigue :11: . Some people like it, some don't. Errol, Bazza and many other experienced rb divers like integrated OC, like KISS. I am in a camp that hates it. I like tiny, light weight DSVs like in Drager LAR V and in all OMG breathers, of course

I did warn I was going to have subjective opinion on the subject

I have two SCRs and five CCRs that I dive depending on a "task at hand" and the "nicest" and (most expensive) rebreather in my collection is an SCR :07: (unfortunately way too expensive for recreational markets ). And, it does not even have a PPO2 meter.

I think the bottom line is that it largely depends on the individual needs, price, features, type of dives, frequency and compromises that you are willing to make. I think the best way is to try a few rebreathers and see which one you like best :07: .

Cheers,

Pawel

 

[caveseeker7]

Let me debate some of your points

You debating? That's a novel idea. :linkz:

"overbreathed" - Do you mean just like a mechanical CCR such as KISS?

No.

whilst a SCR, when operating correctly, will have predictable PPO2 depending on the depth and mix.

Problem is, they don't always operate correctly. And "predictable" isn't good enough for me, I want to know. But that's just me ... rule #1 when diving a rebreather, always know your pO2.

That aside, I was just stating my opinion. And it's plain and simple: I don't dive an active-addition SCR without pO2 monitor. When I have one I check it, hence there is no difference for me in that respect between SCR and CCR. Which is pretty much exactly as I phrased it before. I never said you can't dive an SCR without, just that I won't.

PPO2 meter is not necessary for SCR operation

You're correct, it isn't. But in my opinion it is necessary for safe active-addition SCR operation.

On the other hand, the safety diving a CCR relies 100% on a PPO2 meter. A dead batery, bad sensor = no diving, period.

Only if your CCR relies on batteries. You can always finish a dive safely with a sensor or two gone bad, I wouldn't start a dive that way, though. No big deal, you carry spares in your safe-a-dive it as you carry O-ring for your tank valves. If one of those goes and you don't have a spare you can't dive, either. Not OC, not SC, not CC.

Yada, yada, yada ... So, I agree to differ with you on that one

On what? You missed my point above, and I never discussed pros and cons of SCR and CCR in regards to hypoxia and hyperoxia.

In regards to DSVs, an OC-integrated one allows you to switch to your bailout without removing the mouthpiece. It also allows your dive buddy to do that for you should you be incapacitated. So I consider it a valueable safety addition. Regarding the weight, UW it shouldn't be an issue considering that both the DSV as well as the attached hoses are filled with gas. Haven't tried the KISS one yet, but the PRISM's with the large brass rings is neutrally bouyant UW. It won't raise over your head when you take it out.

I think the bottom line is that it largely depends on the individual needs, price, features, type of dives, frequency and compromises that you are willing to make. I think the best way is to try a few rebreathers and see which one you like best :07: .

That we can agree on.

Cheers

 

[caveseeker7]

Would I not alse more or less instantly need to get something like a (pricey!) VR3 to calculate my NDL and/or Deco? With the PPO2 not being constant throughout the dive, is pre-planning software even an option?

If you want a deco computer you'll need one that does pO2 calculations in addition to fO2. For nitrox they are available from DeltaP, Cochran and Ambient Pressure. For He mixes they are available from Hydrospace, DeltaP and Cochran. The nitrox computers are in the $500 something to $900 range, the trimix computers between $1,200 and $1,600.

You can get constant pO2 tables from NAUI in RGBM and IANTD in VPM-B.
There are matching computer software for deco planning, GAP for RGBM, V-Planner for VPM-B. The Hydrospace Explorer uses RGBM, the VR3 is supposed to be released with VPM-B sometime soon.

I got NAUI's RGBM constant pO2 tables in my class for different setpoints. Welded them in to keep them in my pocket. Bozanic's "Mastering Rebreathers" also has tables in the appendix

In fact, this whole plan for a rebreather has come about because I was planning on getting a set of doubles

For myself, when I need doubles there's better a rebreather in between.

Do any rebreather divers ever "meet up" in the caribbean, florida, etc. for diving?

There is the big Zero Gravity meeting on Grand Cayman for the last couple of years.
Another one for Inspirations and Evos only I believe. Plenty of RBs in FL, Doug earlier in the thread is your man for Dolphin and Azi. For KISS RBs check Jetsam's website, they have their instructors listed.

As Pawel said, see if you can take an intro on units you're intrested in.
Rebreather intros are give you a good idea of how involved pre-dive and maintainance for a particular unit is, give a you a bit of first hand experience and are fun.

 

[MrConclusion]

Pawel - I'm with you on the SCR/CCR debate, and it's good to hear it from someone with experience on both types. On a SCR a PPO2 monitor verifies that everything is working fine, BUT if the PPo2 monitor fails then theoretically the rebreather will still be working. But a CCR relies on the PPO2 monitor for even basic operation. That's the part I'm not ready to deal with yet.

CaveSeeker7 - I also agree with you that I wouldn't want to dive EITHER TYPE without some type of PPO2 monitor, at least something like a Draeger OxyGauge if not an intergrated system like Uwatec's solution. I also agree that CCR's are more efficient and have an elegance in their operation. Maybe I'll get there someday.

QUOTE: "For myself, when I need doubles there's better a rebreather in between."
MY RESPONSE "That's what I started thinking when I began considering doubles!"

As far as the bail out open circuit being on the DSV or separate, obviously I have no experience with either one, but if I had to make the choice right this minute I think I would prefer a separate bail-out regulator. One reason is that it would be independent from a mouthpiece/valve/physical failure in the DSV. Also I like the look of the smaller, simpler DSV's; they <u>appear</u> cleaner and more comfortable. I also have no problem retrieving/changing regs underwater and won't be diving in heavily silted or restrictive cave environments.

I found a rebreather instructor in my area on the internet. Does anyone know anything about Jeff Johnson of DiveSafety? He teaches the inspiration, megalodon, and azimuth. Not the dolphin, but I think I will contact him for at least an introductore class on the Azimuth and see what happens.

 

[Dr. Doug Ebersole]

I don't know Jeff Johnson but I looked him up on the IANTD website and he appears very well qualified. As a fellow IANTD instructor, I'm sure he is very well trained and could be very helpful to you. If you have any plans to come to Florida this summer, I would be more than happy to work with you as well on the Drager Dlophin and/or the Azimuth. I can't help you with CCRs, though! Best of luck, and welcome to the world of bubble-free diving!

 

[jagfish]

Conclusion...
Why not fill out the rest of your profile so other posters know where you hail from...

 

[MrConclusion]

Debersole - Thanks, I may very well take you up on one of those kind offers.

Jagfish - Ok, good point, I have added more information. Just don't expect it to be very interesting or you'll be disappointed!

 

[jagfish]

Jagfish - Ok, good point, I have added more information. Just don't expect it to be very interesting or you'll be disappointed!

Hey, no worries...

Now everyone know where you are, so other posters can know if they are close to you, or can make suggestions based on your location...

Best wishes with your endeavor...