Drager Dolphin:

[Norm]

I am about to take the plunge. This particular model is available locally, the training for it is available locally, and this seems to be the model of choice for rental at many resorts. Does anyone own or have extensive experience with the Dolphin, that they are willing to share?
Thanks,
Norm

[jepuskar]

I have been researching this product for over a month now...I have obtained training manuals from TDI, ANDI, and have 2 other books about rebreathers in general.

The only reason I am not taking the plunge right now is I don't want to use it where I live..Chicago area. I don't want to rent this equipment, but would feel comfortable owning it so I just cant justify it right now.

I am still thinking about taking the PADI course on it which my instructor can teach me. I might do that this summer just to see if I really like it.

From my research I do find it to be a solid and proven unit for SCR diving. Don't let the CCR guys tell you any different....they are spoiled on their CCR's and rightly so, but when I think of rebreather diving I am only looking at the Dolphin....for now anyways.
:rolleyes:

[BigJetDriver]

jepuskar once bubbled...

From my research I do find it to be a solid and proven unit for SCR diving. Don't let the CCR guys tell you any different....they are spoiled on their CCR's and rightly so, but when I think of rebreather diving I am only looking at the Dolphin....for now anyways.
:rolleyes:

As a self-described rebreather fanatic, I often recommend the Draeger Dolphin, even though I own a modified mixed-gas Inspiration. The choice depends upon the type of diving one plans to do. For recreational, as opposed to technical, diving the Dolphin makes an excellent choice. It is simpler and less expensive. It is well made and dependable. Draeger has, after all, been building rebreathers since 1899. Parts and service are readily available. It is even becoming fairly common to find them as rental units. For all of these reasons, as well as the basic benefits of rebreather use, the Dolphin makes sense! ;)

[KentCe]

Like everything else, no one thing is right for everyone. It wasn't right for me, but others seem happy with it.

I highly recommend reading "Mastering Rebreathers".

Btw, I know someone switching to the Inspiration and selling their Dolphin with extra O2 monitor/computer in the near future. Keep an eye on ebay.

[saturated]

Whats your experience and intended dive profile? for 70' rec dives the dolphin will be fine. other than that I would get a ccr. Personally I dont notice a drastic enough difference between the dolphin and OC to justify it. Also dont dive it blind, make sure you get an oxygauge.

[jetfixrguy]

I myself have also been looking at the Dolphin model. I have been doing alot of research about this specific model. My conclusion is that it should make a great recreational unit but thats about it. My problem is that there is only one person I know who dives it in my area, so It might be a little difficult to dive it as much as I want to do. Unless I become extremely self proficient, which is what I want to do anyways. Just my .02

[compressor]

Nice unbiased discussion. I am too taking the plunge after taking some training.

Can it be used for moderately deep dives (100-130 feet). I know you can't do that with High FIO2, so can you do it with less oxygen? or is this a contradiction?

Thanks

[padiscubapro]

compressor once bubbled...
Nice unbiased discussion. I am too taking the plunge after taking some training.

Can it be used for moderately deep dives (100-130 feet). I know you can't do that with High FIO2, so can you do it with less oxygen? or is this a contradiction?

Thanks

they can be used to 130 without any special mods, although the mix is pretty lean and as you approach the surface the risks increase especially if a jet becomes partially clogged.. A PO2 monitor is a must.. flow rates are pretty high with lean mixes so the gas extension isn't that great but its quiter than OC..

[jepuskar]

I think if you push it to 130 feet with EAX32 you are looking at a PO2 of 1.6 I believe. It will bubble alot more as what PSP mentioned...the flow rate is higher so your bag will venting more gas.

This doesnt attract me....what attracts me is it capabilities on shallow dives. For instance, Colombia Shallows in Cozumel...30 ft max reef......excellent reef and life everywhere.

With a dolphin you could use the EAX60 and with a 28.3ft tank, you could have an air supply of 140 minutes. Max depth would be 44fsw with a PO2 of 1.4 so a 30ft dive..not a problem. Ohh man, your no-deco limit at 30 feet is something waaayyy longer than your air supply. Your other limiting factor is your 24hr exposure to PO2.

Man, I am getting excited just thinking about a 2hr+ dive on that reef..a quiet dive no less.

However, not everyone would be happy with a 30ft dive.....you could find a nice meeting point..maybe EAX50 or 40 that gives you the depth you want.

Anyway, I highly recommend the TDI Manual for the Dolphin. Excellent material..all of the values I used above came straight from that manual. good stuff.

Ok, Im too fricking excited right now...darn you guys.hehe

[bill harvey]

@ 130 feet with eanx32 you would only have 45 mins of O2 exposure time for 24hrs. That is if you are staying withing the rec limits of nitrox, since they give no SI credit for O2 exposure. i would just dive deep with OC and enjoy the dolphin when you can take full advantage of it in the shallower waters. then take an advanced nitrox course and really enjoy it

[compressor]

Thanks for the wonderful replies.
LDS states that setting up and checking the Dolphin is too cumbersome. Kindof discouraged me from taking the course.
Now I don't know what to do??

[madmole]

Thats easy, ignore the local LDS!!, unless they dive the Dolphin themsleves they are as qualified to pass opinions as you are to give medical advice

Go find a store/place that uses and trains on the dolphin and get yourself a try dive organised, then you'll be in a much better position to judge

[saturated]

It may take a little more time to set up than OC but when everyone else on the boat is switching tanks and redoing their gear, you can kick your feet up and get a quite laugh in. If the majority of your time is spent mid level on a reef, then the dolphin will probably be a great add, bump to madmole, get a familiarization dive in.

[jepuskar]

Ofcourse rebreathers take a little more maintenance, prep, cleaning etc......look what you get to do with them.

You really need to evaluate what you want out of it and whether or not you can be thorough with all the pre/post dive setup.

To me, the dolphin doesnt look that bad to set up/tear down. Be very thorough though and dont get complacent....if you think you will..then DONT dive it.

I thing I always think about is the idea of forgettin to turn on your tank. In OC it will be immediately apparent...with your rebreather it will not and you could die.

[BigJetDriver]

jepuskar once bubbled...
You really need to evaluate what you want out of it and whether or not you can be thorough with all the pre/post dive setup.

To me, the dolphin doesn't look that bad to set up/tear down. Be very thorough though, and dont get complacent....if you think you will..then DON'T dive it.

The thing I always think about is the idea of forgetting to turn on your tank. In OC it will be immediately apparent...with your rebreather it will not and you could die. [SIZE=3][FONT=times new roman][COLOR=darkblue]:)

These ideas presented by jepuskar are important and worth repeating.

The Dolphin IS a good, solid recreational diving SCR. You CANNOT, however, treat it just like OC diving. You must be conscientious in your pre-dive checks, and your post-dive clean-up!

If you follow your training, the above-mentioned procedures will become second-nature, and will be easy.;)

[jepuskar]

Thanks BJD69,

To be honest, I am very hesitant about the rebreather world. I am also very very excited. I have researched the dolphin and consider myself very educated in the theory portion of the unit. I have a very good grasp on how it works, but this means nothing until I can apply it.

I guess that is part of the fun of diving in general...the inherient risk involved..with rebreathers your taking that risk a step higher which is both positive and negative.

Either way, I will take the leap soon enough. :)

[caveseeker7]

... where are you, geographically?
No Aqualung/Dräger dealers around?
No instructors for the unit?

Go with the advice given above, find an instructor and do a tryout session.
Gets you a close look at the unit, how it works and how it needs to be prepped for diving. Best of all, you get to experience it. :D

If you ever seriously consider getting one, make sure you get a way to watch the PO2. Either the Oxygauge, Uwatec ZO2/Oxy2 combo, or both. On that kind of unit it's necessarry, even though neither Däger nor OMG install PO2 monitors as standard equipment.

[jepuskar]

To further add to my virtual dolphin price....I have already mentally figured in the cost of the Oxygauge and the Uwatec setup.

The oxygauge connects directly to the new breathing bag, but the Uwatec is inline with the breathing bag and hose....is this correct?

2 PO2 monitors...seems like an excellent idea.

:)

[saturated]

What is your location? I know of a couple of very low use units for sale. Both due to health reasons. PM me if you want the info.

[BigJetDriver]

jepuskar once bubbled...
To be honest, I am very hesitant about the rebreather world. I am also very very excited. I have researched the dolphin and consider myself very educated in the theory portion of the unit. I have a very good grasp on how it works, but this means nothing until I can apply it.



That hesitancy has caused you to do the right thing and research the subject thoroughly.

Now you know that, depite some of the hoodoo that gets passed around about rebreathers, they are basically simple machines in terms of their design philosophy. Yet you already know that you cannot treat them like OC units and expect to survive the experience for long.

Caveseeker7 made an excellent point about getting a try-out run to see if it really is what you want. I would echo that, and suggest that you do just that if you can.

I feel sure that the others who have contributed to this post would agree that you are going to enjoy the continuing rebreather experience a lot! (Some old "geysers" on this list have been doing it for years and years!!!)(...and rebreather diving as well!!):D

[caveseeker7]

jepuskar once bubbled...
To further add to my virtual dolphin price....I have already mentally figured in the cost of the Oxygauge and the Uwatec setup.

The oxygauge connects directly to the new breathing bag, but the Uwatec is inline with the breathing bag and hose....is this correct?

2 PO2 monitors...seems like an excellent idea.
:)

Three sensors, actually, with two readouts. One in the bag for the Oxygauge, two in the Oxy2 hose connector. :)
Of course, you can always use the bag connector to hook up a VR3 or HS Explorer, so you have back-up computing, too. Will leave you with a vacuum in your wallet, though ... :D

[Scuba Chip]

I have about 125 dives now on the Drager SCR units (Atlantis/Dolphin, I have never used a Ray). It might be 123 dives, maybe 128 dives, but my total is in that area. I find the greatest advantage to be when diving in the 60' - 120' range. You get so much more bottom time than with OC. You can easily get a one hour bottom time at these depths and still have plenty of gas for any necessary deco. With SCR, You don't have to worry about staying out of deco, IF You have been properly trained. You can't imagine how much closer You can get to sea life (the big stuff) when You are without sight and sound (bubbles).
I liken the difference between OC and SCR to the difference between driving a car and flying a plane, respectfully. You have to pay attention to the DETAILS with SCR. You have to have enough self discipline to establish a routine for each and every dive. As long as you are willing to do this, then SCR's are safe, effective and fun. But, if you dive with a buddy who is on OC, You lose all the benefits of SCR, 'cept the warm, moist breathing gas. :)

[jepuskar]

Hey ScubaChip,

Very impressive usage..hopefully I'll be there one day.

Without looking at any materials...isnt the dolphin much better closer to the 60 foot range than the 120?

Ok, I'm not trying to tell you anything you dont obviously know, but let me explain what I know....

The deeper you go the leaner the mix you need, which means a higher flow rate which intern means more bubbling of the unit. Your gas will be used up quicker. Another important aspect is your no deco time....using EANx32 your no deco max limit is 20 minutes at 120ft..we know the air in your breathing bag will be less than that so this will be even less. Also your PO2 will be around 1.50 at 120ft.

I'm not sure I agree with you on the deeper aspect.....in my opinion 20-80ft is the prime range to use this unit in....then again, your the one with the experience..not me!

Can you explain how you get 1hr bottom time below 100ft on this unit..even if you went to a larger cylinder, your still going beyond the no-deco limit..I am ofcourse assuming you want to stay within no-deco. Also, I am assuming a goal PO2 of 1.4 - 1.6.

Thanks,

Jason

[Scuba Chip]

Hey Jepuskar (Jason),

With the Drager SCR's (Atlantis/Dolphin) there is no need to fear going into deco. More often than not, I have a deco obligation diving these units. And, I am very comfortable doing so.

I always use the middle of the three orifices for flow rate selection. This simplifies procedures, standardizing pre-dive protocols for me. This easily gives me a one hour bottom time, PLUS any necessary deco, whether I dive to 60' or 100'. You DON'T want a leaner mixture at depth. Nitrogen is still an enemy.

The O2 level actually inspired, in your lungs, is less than what comes out of the EAN tank. Using EAN32 is almost useless in these units, 'cause the actual inspired O2 level, in your lungs, from a tank of EAN32, is about EAN26, which isn't much of an advantage over EAN21 (Air). On the other hand, a tank mix of EAN40, will result in an inspired O2 level, in your lungs, of about EAN32. You ALWAYS have to be mindful of Your MOD (Max Operating Depth) remember. This is a limiting factor.

You plan for "Inspired" O2 levels, not tank EAN levels. Using a richer mix, deco times are reduced as well.

Hope You find this helpful :)

[jepuskar]

I understand everything mentioned, but I am still a little confused on why you dive your unit like this.

The middle of the three orifices is the 50% orifice...if I remember dont they come in 40,50, and 60, with an option for 32?

Ok, lets say you ARE using EANx50 which might turn out to be 40%. Doesn't this put your PO2 value at 120ft to 1.85?

I'm not going to go any further because I am speculating...could you please give me more specifics...I am really trying to understand your methodology and learn something here.

If you could answer these questions for me I would appreciate it.

What is the EANx fill in your tank?
Which orifice do you use..40,50, or 60?
How deep will you go on this combination?
What do you plan your workload to be? Light, moderate, heavy? etc?

Do you dive with a PO2 monitor and if so, what does it say at 120ft?

Thanks in advance for answering these questions....I'm not trying to be a pain, I just think this is good stuff to know and your input would help me and I'm sure others.

Thanks,

Jason

[fins wake]

... Jepuskar! You've actually posted the right questions.
You ALWAYS have to be mindful of Your MOD (Max Operating Depth) remember. This is a limiting factor. It is not the only limiting factor, however. Again, we're talking only about the fear of hyperoxia, and not the fear of hypoxia, which most mass constant flow SCR users should fear more.

Using the inspired oxygen fraction (FO2) equation that you will learn when doing the course (and which all CMF SCR users should know off by heart), and assuming manufacturer's recommended flow rates, we find that Scuba Chip has calculated on a steady oxygen metabolism (VO2) of 1,2 (and a 4 litre Dräger tank).

This metabolism, however, can fluctuate greatly depending on exertion (e.g. currents, CO2 buildup etc)!

Fortunately, Dräger has counted on all of this, and with a metabolism of 1,9 (which I've experienced myself at depth) you'll be closer to EANX27, with a metabolism of 2,5 (very high and unusual but by no means impossible!) you'll still be diving air ...

The risk of hypoxia is very low if you follow manufacturer's guidelines on flow rates - which Scuba Chip has done - but you should NEVER change these rates to a lower value than specified without knowing what you're doing, without using an oxygauge or similar O2 measuring device, and without calculating likely FO2:s beforehand.
You plan for "Inspired" O2 levels, not tank EAN levels. Not entirely correct. You plan for inspired O2 levels as far as decompression is concerned, but with tank pre-mix as far as MOD is concerned.
Using a richer mix, deco times are reduced as well. Don't get too hooked on the 'Nitrogen is still an enemy' way of thinking. As we have seen, if the VO2 changes due to unforeseen circumstances, you will be diving lower FO2:s anyway and therefore you should not attempt minimal decompression times. This is actually easier to calculate on many CCR:s!

Due to other unforeseen circumstances (nose breathing, loss bail-out scenarios etc.) the Dolphin is IN NO WAY an ideal decompression diving scuba device! In fact, Dräger themselves strongly advice against decompression diving on the Dolphin SCR.

If I wanted to dive the Dolphin on decompression dives, I'd rework it to a KISS-Dolphin type CCR (and then it's purely on your own liability!). If - as Scuba Chip is - one is of the opinion that 'Nitrogen is the enemy', it is helpful to know that a KISS-Dolphin is quite easy to keep a constant ppO2 on at depth, actually easier than on the SCR! Or one can get an ECCR such as the Inspiration or Prism Topaz. Of course, a CCR has other risks, a KISS-Dolphin CCR will definitely kill you if you don't know what you're doing.

I would strongly advice against using the Dolphin as Scuba Chip is using it, however. Wrong tool for the job. Sorry, mate!

Now I'll step off my box ... :box:

Oh, and you've made good points, Jepuskar! You're not a pain, you'll make a fine Dräger diver! Keep those questions flowing.

[padiscubapro]

I would also like to add, if the person has a PO2 monitor the loop can be adjusted simply by exhaling out the side of the moutpiece or nose and forcing the demand valve to add fresh gas..
the greatest liklihood of high po2 occurs while the diver is decending while using a gas thad has an MOD deeper than the dive depth or a diver being worked considerably less than planned.. in this case other than a gas switch block or a bailout bottle with a lower fo2, the diver has to endure this higher po2 or ascend to a shallower depth.


The use of non standard gases (with respect to the nozzle) is a simple concept but is not taught in many drager classes..

[fins wake]

The use of non standard gases (with respect to the nozzle) is a simple concept but is not taught in many drager classes..Actually, some Dräger instructors do teach you things that are 'outside the envelope'. Things like shutting off your valves to check the ppO2 drop (gotta have an Oxygauge! Don't try this at home, kids!), or things like diving deep to an absolute setpoint of ppO6 =1,6 (which, remember is always more in real life by a factor of 0,045 per bar, i.e. often close to ppO2 1,8 due to the placement of the sensor, not a lot of people know this ...). :D

I think all these exercises are good under (competent) instructor supervision. Have I ever done them? Well, I had a competent instructor ... :tease:

Also, one can do SCR decompression courses on a Dolphin, e.g. with ANDI ...

Would I ever recommend any of these exercises on an open scuba board to newbies? Nope. It's strictly manufacturer's guidelines only. Besides, I reallydo believe that it's better with a CCR for decompression dives.

[padiscubapro]

fins wake once bubbled...
Actually, some Dräger instructors do teach you things that are 'outside the envelope'. Things like shutting off your valves to check the ppO2 drop (gotta have an Oxygauge! Don't try this at home, kids!), or things like diving deep to an absolute setpoint of ppO6 =1,6 (which, remember is always more in real life by a factor of 0,045 per bar, i.e. often close to ppO2 1,8 due to the placement of the sensor, not a lot of people know this ...). :D

I think all these exercises are good under (competent) instructor supervision. Have I ever done them? Well, I had a competent instructor ... :tease:

Also, one can do SCR decompression courses on a Dolphin, e.g. with ANDI ...

Would I ever recommend any of these exercises on an open scuba board to newbies? Nope. It's strictly manufacturer's guidelines only. Besides, I reallydo believe that it's better with a CCR for decompression dives.

I was trying not to put down the most agencies drager programs.. The ANDI programs do teach alot of other stuff including a decompression class..
What many people don't know is the FIRST non military drager class was written by ANDI and was done in germany many years ago.. this was the basis for most of the programs nowadays, while ANDI continued to add extra material and make the classes longer other agenicoes got involved and did the opposite..

ANDI is just about ready to release its 4th (or 5th dont remember) revision of its text...

but the key thing is the only way to really do deco on a drager is to be overly conservative and have po2 monitoring...

[jepuskar]

This is some really good stuff guys. I think I have pretty much accomplished what I set out to do and that was to really understand the concepts behind this unit. I understand everything being said.....surprises me..hehehe

I just wanted to add that although one can dive the drager to 130 feet, I really think it is just not worth it considering the tradeoffs. I really think 20-80 feet is a real good range to get the most out of this unit.


Than again, I am a reef diver. I'm happy at 20 feet or 80 feet, as long as their is some kind of reef around me. The thought of diving the dolphin at 30 feet using EANX60 is really appealing to me because of the lack of bubbles, really no worries about deco, and a bottom time of 2 hours+ with the right supply tank and scrubber time, plus no dry mouth and your PO2 levels would not be near hypoxia because of the rich blend and not near hyperoxia because your roughly at 2atm which would put your PO2 at 1.20 right after a system flush, but it would most likely be around the 1.00 range most of the dive.

Then again, diving to 80 feet still is appealing because of the bottom time achieved, but you still would have to becareful and plan a little better.

I am not going to question a person who has 125 dives on the unit to my zero.....but I do know how I would feel comfortable diving this unit..so each to their own. :)

Jason

[fins wake]

... a Dräger SCR, right?
which would put your PO2 at 1.20 right after a system flush, If you're on a constant mass flow SCR such as the Dräger, you won't really need to worry about 'flushes' (i.e. releasing loop gas through the nose three times or so in order to activate the bypass valve) unless you're ascending.

I think you might be confusing, say KISS-style CCR:s and a CMF SCR? Easily done on the web and if one hasn't dived them, so I'm not being sarcastic. I had these problems understanding the different concepts in the beginning as well. :sheepish:

But cruising a long at a steady 30 feet (or 60 feet or whatever) the mass flow system itself will take care of holding the ppO2 reasonably steady. (Remember, it will vary if your oxygen metabolism varies, e.g. due to currents). I do 'flush' upon ascending, however. Good practice.
I am not going to question a person who has 125 dives on the unit to my zero Absolutely, not my intention to flame Scuba Chip for his personal diving habits. :embarr: :mgun:

Scuba Chip has more dives on his SCR than I do. However, he is advocating something which is specifically argued against by Dräger themselves (on page 17 of the manual, I think) and which is supported by ANDI only provided you do their course and run a different configuration. If one is non-certified or new to the Dräger series one should be aware of this, that's all.

Anyway, enjoy your diving, Jepuskar!

[Scuba Chip]

Jason

To answer the questions you posed: You wouldn't use EAN50 on a dive to 120 feet. As you point out, your PO2 would be too high for that rich a mix, at this depth. The mix I use depends on the depth I am going to, but I always try to use the richest mix I can - highest O2 level - mindful of the MOD for that mix. I always plan for moderate workload and use the middle orifice. I have used a PO2 monitor on many dives, but not on all my SCR dives, relying on estimates of inspired O2 on these other dives. In my experience, the manual estimates are reliable. Your actual O2 inspired level will vary, and subsequent dives on the same canister of CO2 scrubber affects inspired O2 levels (obviously). Initially, I was fixated to the PO2 monitor, and not enjoying the dives. All divers need to admit to themselves that when it comes to "rates" for gas absorption, and elimination - whether on OC or SCR - it is all about estimates. We can calculate all we want, but the actual absorption / elimination rates are not exactly what the formulae suggest. Formulae can NEVER account for the physiological variables. I always dive with my integrated UWATEC computer. I am a big believer in slow ascents, and never shy about a deco stop. It's like going to confession - it forgives lots of sins. To aid an effective deco stop, you simply cross your arms in front of you. This arches your back into the rebreather bag of the Drager unit, flushing it, increasing Your inspired O2 level at stop. No harm in that.

I wouldn't use a Drager in 20 fsw. I can get plenty of time from OC at this depth, and there are less details to deal with in OC.
In my opinion, the Dragers are most valuable in the 60' -110' or so, foot range.

I was originally trained on the Drager Atlantis. The Atlantis used vinyl rebreather bags, chrome plated brass fittings, and carried a steel tank for the nitrox. My instructor developed this unit with/for Drager. He wrote a manual for this unit in use today. My insructor was selected to introduce the son of a very famous French ocean explorer to this unit. Parenthetically, this very famous French dive group had never used rebreathers before. That revelation really surprised me.

I was one of the very first - on this side of the Atlantic - to use the "new" Dolphin version of the Drager Atlantis. That was 5 years ago. The Dolphin employs a nylon material for its bags. These bags have a handy plug for cleaning and rinsing which the Atlantis lacked. The Dolphin uses polymer fittings - a plastic type material. It came supplied with an aluminum tank for the nitrox. I remember that first Dolphin dive very well. Six of us, all experienced Atlantis divers, jumped in and promptly found ourselves too bouyant. No one was more surprised at the changed bouyancy characteristics of the aluminum tank than the Drager Official diving with us. It was his 1st Dolphin dive as well.
My personal preference is for the nylon bags and a steel tank - 'cause of the bouyancy characteristics.

I was taught to use these units for decompression diving by Drager officials, and Drager representatives. At least 2 of the technical training/certification agencies that I am aware of, teach deco use of these units. Would I put a rookie SCR diver into a decompression dive? No way! Not anymore than I would place a newbie OW certified OC diver in a decompression setting.

I am very comfortable diving the Dolphin with decompression obligations. In my dives on these units, 45-50% were deco dives. But all of them incorporated a safety stop, required or not.

I have heard the response of my Drager dive buddies (who I continue to dive with) to questions posed regarding modifying the units for use as a CCR, and I can quote their top guy, who unequivocally says, "run the other way."

I have offered my experience, and expressed my opinion without taking any unwarranted cheap shots at anybody. I don't have to. I don't need to impress you with what I read somewhere. I have experience with these units. And for that I am not sorry - mate!

I hope this is helpful to You Jason.
Should you come across an 'experienced' Drager unit boldly sporting "UWATEC" labeling (and there are a number of these in circulation) I can explain that apparent discrepancy to you as well!

If You are serious, and willing to spend a couple of bucks, I can connect you with an expedition (forming now) that will get you rebreather certified, give you about 25 rebreather dives, and provide you the diving experience of your life! PM me for details.

May Your dives be long and Your surface intervals short :)

[Tigerscuba]

I have dolphin, well at least an atlantis with dolphin guts. Overall its a pretty good rig. I think what it all boils down to is what do you want out of it. You see there are people who who enjoy reefs and wrecks in the mid ranges, say 50'-100'. If this is your dive profile then the dolphin will indeed be an outstanding unit for you. But if your a trimix diver who likes the wrecks at 150+ then a ccr is the only way to go. I think if you posted your experience level, typical dive profile, and goals you may get better advise from us. The best approach in my opinion is to set down and write down your profiles, intended goals, and what you want out of diving, both now and down the road. Then pick the best tool for the job.

[Jaytor]

Hi folks -

I'm not as experienced a rebreather user as many (most?) on this list, but I'll add my two cents. I owned a Draeger Atlantis (which I think is very similar if not the same as the Dolphin) 4-5 years ago. After diving with it for a while, I decided to sell it and switch back to OC. For me, the advantages didn't outweigh the disadvantages.

I'm a semi-pro underwater photographer (meaning I sell my photos but don't make a living at it) and was hoping that the SCR would allow me to get significantly closer to marine life. The Atlantis has some advantages over OC, but not much. It still generates bubbles, although they are reduced compared to OC and come out of the back of the unit instead of in front of your face. However, unlike OC, you can't hold your breath for a minute while you approach to avoid bubbles. The oriface is open all the time whether you're breathing or not.

My bottom times with OC (Alum 80) are typically 70-90 minutes. I generally don't like to stay down longer even if I have air in my tank and often come up with >1000psi left. I had a hard time finding >EAN40 at most dive locations, so my bottom time with the standard tank on the Draeger was no longer anyway. And my theoretical MOD was reduced compared to my typical EAN32 OC mix.

I was always somewhat paranoid about the scrubber, so changed the scrubber material between almost every dive, particularly if I was down for >60min. This meant that my maintenance time for the rebreather was on the order of 30min during surface intervals. This left relatively little time to work on my cameras, and I often found the other OC divers had to wait for me.

I am quite interested in rebreathers, and would consider getting a CCR unit. A CCR unit would virtually eliminate the bubbles and provide real advantages in stalking marine life. Most have a scrubber and gas capacity that will easily allow 2-3 hour long dives with minimal maintanence between dives.

I don't think the SCR units are significant safer than the better CCR units. Both require considerable training, diligent maintanence, and careful attention while diving.

Once I had the Draeger configured the way I wanted (PO2 sensor, pony bottle on each side to balance weight), my investment wasn't that much less than a CCR rebreather.

So, if you're serious about getting a rebreather, you might want to take a closer look at the CCR units before making a final decision. Hope this helps.

- Jay

[fins wake]

... honest to God, I don't want to start a flame war with a fellow RB user. I enjoy a ruck, but not with someone who has more dives on the specific unit than I do. (Nah, I don't want to impress anybody, I do have experience on the units myself, I do want people to follow manufacturer's recommendations and live long etc etc. Peace!)

Point is, I still think the Dräger's a much worse decompression device than the Inspiration, say, and not just because Dräger themselves say so ...

Anyway, to end on a lighter note, a quick flash-back from memory:
My insructor was selected to introduce the son of a very famous French ocean explorer to this unit. Parenthetically, this very famous French dive group had never used rebreathers before. The father of Jean-Michel, the great Jacques actually did experiment with very early and simple rebreathers before joining up with Emile Gagnan to make the first 'modern' regulator, the aqualung. He describes it at the beginning of his seminal work, Le Monde du Silence. Basically he oxtoxed and almost killed himself, which really ties the knot to the hyperoxia threads on this forum (the 'narrowing white tunnel' etc.). End of experiment. No more rebreather diving for him. The rest is history.

So, if you're serious about getting a rebreather, you might want to take a closer look at the CCR units before making a final decision. Amen! But dive safe. And since the great Jacques has been mentioned, let me briefly cite another of his sayings: Happiness for a bee or for a dolphin is to exist. For Man, it is to know this and ponder upon.

Dive safe, y'all.
K.
(with apologies for my French translation.)

[jepuskar]

A system flush in the Drager is considered by me to be getting rid of the entire contents of the inhalation bag....it is a pretty wise thing to do right before ascending or even throughout the entire ascent. Some people even go as far as saying switching to OC for the ascent.

Maybe a system flush in a CCR is different, but I definetly want to know what I am breathing when ascending...especially for lower mixes.

Jason

[fins wake]

Some people even go as far as saying switching to OC for the ascent. Never! I think - and hope - this is an area where Chip and I will be in complete agreement. I've never switched to OC for ascent on either CC or SC, and never will use it as SOP.

This is typical OC-induced ludditeism. Unless your loop is flooded, or you're really spooked for whatever reason, you never really come off the loop! This goes for both SC and CC.

I do my flushes after ascending, not before. There's really no point in doing it before, you just waste diluent.

Jepuskar, I believe you're ready for the course. Go for it, mate! ;)

/Edit: 'flushes' separated from 'after' in italics.

[saturated]

There alot of Dolphins in closets, mine included. The reason they are in closets is quite simple. A low pressure steel tank with a good fill gives me as much bottom time as the dolphin with half the hassels. Now a ccr on the otherhand is a huge leap forward and is well worth the added setup/teardown time. Dolphins are pretty good units. the problem is most guys I know outgrew them to fast and now have a $3500.00 rb collecting dust(Complete setup). If I had to put my stamp on something it would def be the inspiration. Your not likely to require more than it has to offer.

The flush prior to ascending is taught to provide a known mix prior to ascent. Most guys dive these units with no way of knowing their mix, so having a known mix prior to ascent may not be the worst thing to do. In reality though it is more for sanity than anything else.

[undah20]

I think you'll like the Dolphin a lot, it is a good, reliable unit for most people.

First a re-read of tigerscuba's post seems appropriate to me. It seems a good summary, and then I can post my own rambling here.

Some of the things I've found with my expeirience using the Dolphin: Excellent for the experienced OC diver who wants to try something new and venture into something other than OC (all with PROPER training of course). You 'learn' a new way of diving, and don't rely upon your past OC experience as thinking it will make you good with SCR diving - keeping an open mind of course.
The lack of bubbles do help you get closer to the aquatic animals, but not tremendously so. Both language has a lot to do with it also. And if you are with other OC divers nearby, forget it. (Jaytor have you tried purposely creating an exhaust before approaching the shot ? - this acts similiar to the breath hold technique you employ in OC). But there is a periodic exhaust unlike CCR. You might really like the far more quiet aspect of the SCR versus the minimized bubble aspect (if you can understand the difference)? I think the effect of the better silence is an asthetic that will draw you more into SCR and beyond.

I have always employed BOTH the Drager Oxygauge and Uwatec Oxy2transmitter with XO2 wrist unit for diving on the Dolphin. I cannot see why SOME Drager divers feel they dont need ppO2 monitoring? To me it is like diving without a depth gauge and thinking it doesn't matter as you know the reef like the back of your hand. Things can always change - workloads, comfort levels, ANYTHING). I have the best of both worlds. I may have overkill redundancy, but with 3 monitors - I know both my breathing concentrations and real-time inhalation loop as well (as the two different units are in use in different areas). It you have to choose just one, IMO, the Uwatec combo FAR benefits outweighs the oxygauge - you know real-time actual breathing loop O2 concentration).

I flush the loop (through nose exhalation) at the end of every dive at the shallowest of safety stops). I want the benefits of inspiring the loop prior to exiting the dive. Bailout is there as secondary bailout, not for gas switching to avoid hypoxia.

I find that even after extensive DCR/SCR (depth air consumption/surface air consumption) rate configurations, workloads do end up changing as experience increases. The limiting increase of of ppO2 for dives in and around 115ft +/- 10 feet to be very limiting with the Dolphin or any SCR. Benefits for shallow dives are outweighed by increased comfort and experienced levels as well. Now, at the point where I am able to make 90-120 min dives (irregardless of target depth - considering no-decompression recreational dive profiles) on 80AL single tanks with 75bar/1000 psi reserve upon surfacing, I've outgrown the purpose of the the Dolphin. Making strictly 30-40 ft dives with OC, I can easily match the Dolphin profile with less maintenance and cost.

Being a deep freak, and very comfortable at depth, again I've outgrown the manufacturer's Dolphin intent. I've been looking extensively into restructuring it for KISS, etc, use, but WHY? I mean, for the cost and headaches, there are CCR out there with much better results (ie Prizm Topaz - same size and weight as Dolphin).

My opinion/post is just to say that with a great deal of experience, you can quickly outgrow the Dolphin. Don't get me wrong, I really like the design and functionality of the unitand I'm not talking about you amking the jump to CCR. I think taking the training on the Dolphin, diving it for a while, renting the unit in your area or on vacations for a good many dives, is a better option and save you a great deal of money in the long run. If you end up getting a Dolphin, you'll be all the more experienced and pleased. If you end up passing it by, going CCR, or staying OC, you'll be pleased with the knowledge and experienced gained by the addition of another diving feather in your hood.

[undah20]

ha ha ha ha, that was funny!

I meant "Body language has a lot to do with getting closer to aquatic life also!"

ha ha ha ha....I'm running for my XL Latte now!:D

And all you CCR divers, are you totally enamored by the total love of no bubbles? Must seem strange to think backwards to OC and SCR with all those bubbles in the water...
aahhh, nothing but the wonderful blue and the sounds of the ocean!

[jepuskar]

Great addition to this thread undah.

CCR really does look tempting and all, but I think a jump from OC to SCR makes more sense to me right now..well not even right now, but in the near future.

SCR seems like the most prudent jump for most people thinking about dabbling in the closed world.

If I decide in the future to go with CCR then yes I will be out some money, but the technology will be better.

Anyway, thats how I look at it.

Jason

[Rob Evans]

And all you CCR divers, are you totally enamored by the total love of no bubbles? Must seem strange to think backwards to OC and SCR with all those bubbles in the water...

Ummm... Yeah actually. Tooling around a wreck (or reef, whatever floats your boat) in no particular hurry without any worries about your exhaled gas bothering the surrounding fauna is an incredibly relaxing experience.

Yes you've got heaps of gas duration etc etc but the peace and quiet is something I've learnt to really appreciate over the last 18 months of diving the YBOD, especially as I've started diving OC regularly recently as part of an OW instructor course. The din is just unbelievable, and my bouyancy's gone all to hell:-)

Quick tip for quietening down a Dolphin/Atlantis - stretch a bit of your missus' hose over the exhaust valve. Doesn't reduce the amount of gas vented but diffuses it nicely into a cloud of smaller, less noisy bubbles. Thicker/higher denier hose are best. Or so I'm told. I pulled apart on pair of "the management's" tights to give it a try and got such an ear-bending I still get the shivers thinking about it. Selling the grandparents for a nice quiet Inspiration seemed like a safer bet & I haven't looked back since, though I do miss Gran & Gramps.

[Norm]

You folks have been incredible! I want to thank each and every one of you for your input/questions/feedback. I learned a LOT more than I ever expected. Thanks guys!
Norm