3. Some Modern Updates

So as we approach the end of our Drager Dolphin Project, we have decided to add some final upgrades to our test Dolphin. As we mentioned earlier, the Dolphin is strictly a mechanical rebreather, and there are no on-board electronics. So therefore, there is not much we can modify from the original design, except for the original (and optional) Drager Oxyguage.

Drager Oxyguage

The Oxyguage was designed as a simple P02 display for the rebreather. In fact, it was so primitive at the time that many owners decided not to purchase it or simply didn't use it. The Oxyguage's P-Port contained an oxygen sensor which was connected/inserted to the inhalation counterlung. The P-Port and sensor were connected by a cable to a console with an LED display. The display would show the divers P02 at any given point during the dive, and also provide alarms if the P02 was too low or too high. Simple enough right? Yes, but extremely primitive by today's standards. The problem with the Oxyguage even then was that it didn't have a dive computer integrated into the electronics. The diver could always see his P02, and that was great (Always know your P02), but one still had to have a separate computer to track his nitrogen loading and 02 exposure. The issue there was that the inspired gas from the counterlung, was never the same as the mix contained the the cylinder. All dive planning was done based on the mix in the cylinder, and not what the diver was actually breathing from the counterlung. Enter 2016 and a more modern solution. To solve the problem, we needed to connect our Dolphin to our Shearwater Petrel computer via a cable connected to the P-Port. We contacted Martin our Dolphin expert at Tec Me in Germany, and he made us exactly what we needed. A cable with a P-Port connected to a Fischer plug. We placed an R-22D sensor into it an attached to directly to the Petrel''s Fischer port. Now we have the perfect solution. Real time P02, oxygen exposure, and N2 monitoring, plus the ability to switch the computer to our bail-out gas if needed.

Shearwater Computer and 02 Sensor

Next, although our Dolphin was new in the box, it did not come with the original Drager 27cf cylinder, but we were able to find a suitable replacement. We decided on the Faber 27cf  low pressure steel cylinder. The problem was that it contains a DIN valve, and does not directly connect to the M26 thread on the Dolphin's first stage. The dolphin is a German rebreather, and therefore the thread size is not compatible with the standard DIN connection we use today. Again, we looked to Martin at Tec Me for the solution. He sent us an M26 to DIN adapter, which was a perfect match.

And lastly, we needed to add a bailout system to the rebreather. As with any rebreather, The diver must have the ability to bailout to a known gas. That known gas it most cases is just plain air. We opted for a 13cf Luxfur Cylinder which mounts nicly to the side of the rebreather's cover. As For the bailout regulator, we went with Dive Rite regulators.

As fun as this project has been for me personally, to relive the Dolphin has wonderful. I hope you enjoyed this trip down rebreather memory lane.

Here is the completed Dolphin next to a few of our other rebreathers.

Visit our website at www.eliteprodive.com for more Drager Dolphin information and training

2. Service and First Dives

I spent this past weekend with Course Director John Lachelt at Giglin’ Marlins in Houston. John is a Dolphin expert and one of the original factory trained technicians for the unit. He also previously owned a shop in Juno, Alaska, where he had a fleet of rental Dolphins. John is the man to see if you have questions about the Dolphin, and I’m lucky to have found someone nearby that was familiar with the unit. John and I started out testing and servicing the machine, and we immediately replaced the bypass hose which had split from being crimped in the box for 17 years. After a full going over, we put the unit in Giglin’s 14 foot pool for a test flight. John had one of the factory 100% orifices, and I had to try it. We topped off one of his original Drager 27cf cylinders with 02, and I eagerly jumped in.  I was surprised how slow the flow rate was using 02, vice the other orifices, and it flows at only between 1 and 2 lpm.  In the water, the Dolphin performed flawlessly.  With the exception of a leaky BC LP inflator, all else checked out perfectly. I was amazed how little the unit vents on 100 percent 02.  It truly feels like a CCR, and it’s actually quieter that my CCR’s. Of course there are limitations to the pool orifice, but using it in the pool is as close to a true CCR experience one can get with a SCR. Sunday we headed out to 288 Lake for a few dives. We switched to the 60 percent orifice, and although the gas venting was much faster than using 02, I was generally pleased with how it performed.  I had only dived a Dolphin previously with 32 percent, and switching to 60 percent was quite a noticeable improvement.  Other than the biting perch and the low viz, the dive was quite enjoyable.  It was fun to get back on the unit, and I now look forward to some mods for it, and introducing some other divers to this classic machine. Next up, we will replace the “boat anchor” of an SPG with a more modern one, as well as adding a PO2 monitor connected to a Shearwater computer.

The original Bypass hose was cracked having been crimped in the box.

New Miflex hose and connectors

New hose is attached

Visit our website at www.eliteprodive.com for more Drager Dolphin information and training

1. The New (Old) Drager Dolphin

Welcome to my old school Drager Dolphin Project.  The idea of this project actually began a while back when I was teaching a CCR course, and explaining differences between the modern-day electronic CCR’s and the early recreational SCR’s. The conversation turned to the Drager Dolphin, its simplicity, and how it functioned as an entirely mechanical rebreather. I later found myself reminiscing about my time on the Dolphin, and how far rebreathers had advanced in such a short period of time. I thought how nice it would be to have a functioning Dolphin to use as a teaching tool, and also as an easy way to introduce divers to rebreathers. I've found that a lot of open circuit divers are interested in rebreathers, but many are not ready to make a $10k investment in a CCR. Many just want to try a rebreather, and what a better way to introduce them with a Dolphin.  The benefit to me would lower operating and maintenance costs compared to using my CCR's for discover sessions. Only one problem, Drager stopped making the Dolphin (and parts for it) many years ago. The Atlantis/Dolphin is still listed on the PADI continuing education flow charts, so I figured there must be people around still diving it. But what I learned was that although it is still very popular in Europe, the rebreather has all but vanished from the United States. It seems as though technology has pushed the Dolphin aside. And I get that! Nobody’s carrying around a 1990’s cell phone, and rebreather divers have moved on to more advanced machines, myself included.  I started by searching the internet for any Dolphin clubs or groups for support, but there were none to be found. I figured that if I was going to do this, I was going to be on my own, or so it appeared.  So I began by searching the internet for used machines. I found a few for sale, but all had seen better days and most looked way too scary to dive. I had all but given up on the idea, until one day...there it was...a brand new Dolphin, still in its original packaging. It was at a pawn shop in Minnesota, and I don’t think they really knew what it was or what they had.  A couple of emails, a phone call, and the Dolphin was at my doorstep.  So, this is where we began.  A journey to add some modern updates to the Dolphin, re-live some old experiences, introduce and teach a new generation of divers about our rebreather history, and of course, to bring this 17 year old Dolphin to life. So follow along over the next few months as we
re-explore the Drager Dolphin.

The original Drager case

Like opening a time capsule

Drager BCD

Scrubber canister 

Drager piston first stage. dosing unit with 40, 50, and 60% orifices, and a very
old school SPG. Step one, service the first stage and the bypass.

LP Inflator hose, flow meter, and fill adapter. No cylinder came with the unit, so
one of the first priorities will be adapting the M24x2 connection on the first stage to
a DIN cylinder. 

Dive/Surface Valve

Exhalation Counterlung

Inhalation Counterlung

The original documents for unit certification dated April 1999.

Visit our website at www.eliteprodive.com for more Drager Dolphin information and training