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I feel I should really save everyone some valuable time by cutting straight to the point.  Please feel free to read the SCR reviews below, but keep this point in mind

If you are interested in moving into the dark side of diving by getting a rebreather - AVOID AT ALL COSTS any SCR's and espcially and eSCR's.  They are a waste of money, and time.  An SCR is just as time consuming to set up and operate and NO measure of safety.  An SCR is just as dangerous as a closed circuit rebreather, but without the increidble gas savings.

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Rebreather Review by History SCR's

Drager Dolphin SCR

purchased my first Dolphin SCR in 1997 and immediately went to get my Dolphin SCR Instructor rating.  It was at the time the coolest piece of technical diving gear I had ever owned.  It took much manipulation and you needed to violate almost every paragraph in the Drager manual that stated "Warnung!"  .  The first units had no Po2 monitor and it was a simple math formula of nitrox in - flow rate - metabolic rate = FiO2 or fraction of inspired oxygen.  The Drager had 3 choices of gas orifice: 40%, 50%, 60% and this was trouble for the new Tech industry as a basic nitrox diver was certified to use up to 40% nitrox and here was a piece of dive gear that required 60%?  A course that has no merit on its own "Advanced Nitrox" course was born to address divers use of increased fractions of oxygen??  When the Po2 meter (single oxygen sensor) was released, it was immediately hacked so you could dive it to higher Po2.  In early years 1.6 was the sport diving nitrox limit and the depth limit on the Drager was near impossible to enjoy within written standards.  The other bastardization was to switch gasses and put a weaker nitrox mix such as a 40% through a 60% orifice.  In this way you could dive it to the deeper depth of 40% MOD, and essentially you would be breathing something like a 32% FiO2.   Now I won't even discuss how we filled half a scrubber with golf balls to make a half fill adaptor as its too embarrassing to admit... Ooops I wrote that down, didn't I?  Well the Drager was fun if you violated almost every written premise, but it was prone to leaking, flooding, caustic cocktails!  It was time consuming, and the unit was damn heavy on the surface!  Yes you could argue that it was equal to a set of doubles, but damn near the same weight.  In the water you sucked like a whore in shallow water,  but as you went deeper was relatively easy to breath.  The buoyancy characteristics were poor as it was heavy on surface, and buoyant in water?  If there are any rEvo divers out there, all you need to do is look at the Drager dolphin and consider the small exhale lung with OPV/exhaust valve, the larger kidney shaped inhale counter lung, the breathing loop with Drager hoses and Drager P-port connections and you realize that a rEvo is a modified Dolphin with a split scrubber.  Can you say "Farfignugen!"

Drager Ray SCR

Ok, the scrubber was a bit of an improvement to the oval shape of the Dolphin that would flood if you looked at it sideways, up ways, or it just decided that it should flood today as it flooded yesterday!  The scrubber on the Ray was smaller and round can shaped.  The counterlungs were built into a "Jacket" style BCD and was too cutesy to be taken seriously.  It was in essence a toy that never went anywhere?







OMG Aziumth SCR

This is a beast!  It was tall in profile and only to be eclipsed on market by Optima as it shares some concepts.  But the Azimuth was a dual cylinder on butt, with an adjustable orifice, and a top mounted scrubber with breathing loop on top... hummm (Optima).    It featured a "Hatch Back" lid that lifted up to access counter lung.  The exhaust mechanism was a PIA to adjust.  The Drager Dolphin was a much great appeal for smaller size.  I don't really recall selling many, but using it as a tool to show divers different SCR models.

OMG Castor C96 Oxygen CCR

This was a loaner from Tom Mount during a Bahamas Blue Holes ccr cave diving trip and I only had a few dives to understand the operations of a fully closed circuit oxygen rebreather, and a front mounted lung.

* I know some tech divers own a Drager Military Oxygen Rebreather for emergency deco, but I just can't justify that piece of gear as there are several working ccr's on any tech trip if need to go back into water?

Submatix SCR

This was a loner unit that a student on west coast had loaned to me as she got one after I had loaned her all of my SCR's and several CCR's to train on as diver and instructor.  Short memory, nothing stands out as significant to want to buy or continue.

*nothing jumped out to me to say I wanna buy?   

Summary of SCR's

This will be an all inclusive summary of SCR's listed that I have owned and dived


*There is NO value to diving an SCR today market, and the above listed SCR's are out of date.  The new idea to introduce an eSCR into the dive industry is a monumental waste of divers money and time.  The marketing gimmick is to have "Training Wheels Rebreather" and then the diver will later upgrade to a CCR.  


*There is no value in trying to revive an out of date semi closed circuit rebreather( s) like Dolphin, Ray, Azimuth, Submatix as it is cost prohibitive if parts are even available.  These items are fine for a collector who wants a piece of history only.


*Do not attempt to modify an SCR into a CCR as there are better and safer alternatives in new or used CCR marketplace.


*SCR's are just as time consuming to build, and pre dive test and are NOT any safer than a CCR.  Do not waste time messing around with all the work for no return, as an SCR is limited.  You can dive any number of Recreational Closed Circuit Rebreathers and have simplicity and no greater time or risk. 



This next review is based on my 40+ years in the dive industry, my nose and instinct to smell a dog pile when i smell it.  I have extensive experience seeing this product being developed, seeing it being tested in Cayman's, its failures and too many divers who have complained that it never works!  I have not owned this unit as I choose to dodge the bullet and not take a head shot. 

*Do NOT waste time with an eSCR!

I was at Dive Tech Grand Cayman's when this unit was demo tested and saw a group of engineers standing around a table sucking and blowing into different orifices, trying to figure out why it was flooding.  And I was exiting Devils cave system in Florida when I passed a diver on this unit, he was on open circuit bail out, and his unit had fallen apart on the dive and flooded.  There is no point dragging on all the stories on this failure.  My advice is  run not walk and just buy a Recreational CCR.

I only have to click a few keys to go to a CCR forum and find endless experts who blabber incessantly about their personal experiences on rebreathers, as well as industry experts who have fallen into the water apparently while wearing a rebreather and are now rebreather experts. My consternation's for the forums is that over the past 20 years I have dedicated myself to full time teaching of rebreathers, while many of these voices are working real jobs and part time instructing, yet full time typing on the internet forums.  Where do these experts get the time to spend all hours of the day on social media, and find time to actually get into the water and dive the dives?  I do not include the 19 years prior that I have taught OC / and Technical although 41 years of dive industry experience is valuable, I will only focus on the most recent 20+ years of rebreather diving/training.


The information below is then based on the fact that as a full time teaching rebreather instructor, that I have personally owned every rebreather that I review, and when it comes to "other" units that I have not owned is based on my travel to all five corners of the globe over 41 years.  I support every opinion with surround facts of the units and dive industry,  and not simply conjecture.  This is professional experience, that is time tested.


The review and reflections on rebreathers are honest, and from the gut without sugar coating and without any malice.  I know almost every rebreather manufacture, not all, but it is a very tiny dive industry and its either a personal knowledge by diving and traveling with the owners, or spending time at dive show or conferences.  Please remember that each and every rebreather that I discuss, they do work as rebreathers to varying degrees of success.   I will only focus on the most successful rebreathers that have had an impact on the market, and I will not review every homemade unit or bastardized unit.


This is above all NOT a paid advertisement for any rebreather, but harsh and biting truth about what works and what does not.  Yes they all "work" to some degree, but some are on the edge.   


My interest begin in 1984 after I graduate from Divers Institute of Technology and choose to work inland waters of Midwest U.S.   The contractor that I worked for had a small hyperbaric chamber with a lock out transfer hatch and while trained at DIT for operating a chamber, we used the chamber for mostly "advanced diver narcosis" experiences.   Chambers are in essence a semi-closed circuit rebreather, that do NOT contain any Co2 absorbent, but utilize a breathing ratio of time to flushes of chamber atmosphere to maintain safe breathing.  Now at this time my commercial dive contractor had an old military oxygen rebreathers that were a curiosity,  but I never got the chance to test beyond surface play.  When I got out of commercial diving and focused on recreational, then technical diving I was doing a fair amount of deep trimix dives in Lake Superior.  One of my favorite deep sites is the Gunilda shipwreck in Rossport, Ontario and it is an arduous task to undertake a week of diving 260 ffw in remote location of Canada.  All of the gas needed, the exertion of loading/unloading of heavy cylinders, long hours of pumping gasses, repeat daily while doing hours of deco in cold water, hurts the body to an arthritic body ache at end of a dive expedition.  When I learned that two American divers were using former military rebreathers (Mk15) to dive the Gunilda, well I was just plain old fashioned jealous and envious!  During this process from '96 - 2000 I had been diving the Drager Dolphin Semi Closed Circuit rebreather only in sport diving depths, but realized the potential for an eCCR.


In 1995 - 1997 I pursued fully closed circuit by researching available units at the DEMA trade show and ooogling over the CisLunar MkV ($18,000).  But my tech mentor Tom had talked me out of this as he said within 2 regular maintenance schedules the cost of service (all proprietary components; sensors, batteries, etc) was equal to a new Inspiration CCR.  This was a tough decision as I had been diving with Cis divers and it was Top Gun.  Not only the tool of the cool tech divers, but even after 17 years of not being manufactured or services, is still  the rebreather that all other rebreathers are measured by.  The CisLunar set the benchmark for WOB, Scrubber, Deco Integrated Set Point Controller, Buddy Light, etc... So in 1999 I pulled the trigger and purchased two Inspiration Classic CCR's ($7,000 ea.) under a bit of discord from my instructor who insisted that I could only buy one.  If I buy two, then clearly I would be sharing it with an un-certified buddy and that was not right.  Well damnit, I wanted two and I paid for two as I new my next step was to be teaching on these marvels.  The inspiration was the death kneel to the CisLunar as it was less than half the price and built on a platform of "mini" mass production.  I traveled to Seattle to train on the Inspo as I had fallen in love with PNW shore diving after training at DIT in Seattle. 


I met some cool dudes that had also trained on Inspos and one of these guys Dave Hancock (of Ideations Dive Alert) invited me to join the 2001-2002 Rebreather Liveaboard Nautilus Explorer off of Vancouver, BC that he had organized.  At this event I would run into Leon Scamahorn (who was my classmate for IANTD CCR cave course taught by Tom Mount and Mark Medows, and host of back up divers including Jim Lockwood, Will Smithers, Del Motts).   On the liveaboard I had also pleasure of meeting Gordon Smith who invented the KISS line of CCR's, and one of his local divers Dr. Greg Grant who performed a live Hypoxia demo in front of about 12 of us divers on the stern of the Nautilus.  It was a shocking display of seeing a diver sitting on a bench and within moments was unconscious!    Now the Nautilus CCR liveaboard annual trip would deserve an entire article by itself as it holds a number of significant events in the dive industry.  On these trips I would see my first view of the Prism Topaz, that NO did not actually work but the diver tried to operate in manual mode?  And the UT240 which was a money pit that Bob Hollis had dumped tons of money on the quest to market a rebreather worthy of commercial or military use.   Due to the price and availability there were a number of Inspirations, and due to proximity to PNW was split between the ISC Megalodon and the KISS Classic.  I had already purchased two Megs ( Std. Meg, Mini Meg) and they were the last units with integrated depth/deco/set point control as designed by recently deceased Will Smithers.   But it was also influenced by the KISS and soon after purchased my first KISS Classic.   And then soon after Gordon Smith demonstrated the Sport KISS on the Nautilus and I needed one of these as well.


So this is the drug of CCR that is equally as addictive as crack cocaine and nearly as dangerous!   I needed every viable CCR, for the reason as stated: I "need them" and I wanted to teach each of these units.  So I will now list units, and then I will discuss each of these on their merits and some of the dirt that is part of the dive industry.  Inspiration Classic, Inspiration Evolution (mini version), Inspiration Vision (real handset/electronics), Megalodon Classic, Megalodon Mini, Megalodon COPIS, Megaldon Pathfinder, Classic KISS, KISS Sport, KISS GEM, KISS Sidekick, KISS Spirit, Optima, Titan, rEvo Manual & Hybrid,  Poseidon MkVI / Se7en, Prism2 and JJ.  


Bullets that I dodged include, but not limited to: Ororborus &  Explorer eSCR. Phew!


I will show a few pictures of events that are special for me in the development of my experience.

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Ray front 1.jpg
Azimuth Alki.jpg
Ron Alki Submatix.jpg
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