Connect with us


The Economics of Choosing CCR Vs OC

Shortly before this story was posted, the author informed us that helium prices had gone up in British Columbia area, and there was less availability. As a result, the break-even point in terms of number of dives has likely gone down approximately 25% i.e., it would take about 39 deep open circuit dives to pay for the cost of a rebreather, training and experience dives compared to 52 as calculated in his story below! As Shockey explained to us, “ If someone contacted me today and asked for a open circuit trimix fill, I would have to tell them, No, I need everything I have for my teaching commitments through the rest of the year,“ he said. InDEPTH will be reporting on the global helium situation in the tech dive world in the AUGUST issue. Note that the gas industry’s trade magazine, gasworld, calls it, “Helium Shortage 4.0.”



By Guy Shockey. Images by Andrea Petersen unless noted.

Technical divers

I teach both open circuit and closed circuit Global Underwater Explorers (GUE) technical diving courses, and I am frequently emailed or messaged from students who have completed their Technical Diver 1 (Tech 1) course and fulfilled their experience requirement for further training. They ask me for advice as to whether they should move forward with Technical Diver 2 (Tech 2) or start down the CCR pathway with Closed Circuit Rebreather Diver 1 (CCR 1). 

There are several factors to consider when making this choice, but one of the biggest decisions concerns the relative cost of both pathways. The up-front cost of closed circuit rebreather (CCR) training appears considerable on the surface: you need to purchase the CCR and the associated parts and pieces to set it up as a GUE compatible system. I decided to do a little math and see at what point a diver would reach a break even point with their CCR purchase as opposed to conducting OC Tech 2 dives. 

To compare apples to apples, I also needed to include both CCR 1 and Closed Circuit Rebreather Diver 2 (CCR 2). This is important because, while CCR 1 will get you the knowledge and training to do your CCR 1 dives in the T1 range (max depth 51 m/170 ft w/30 minutes of deco), you will need CCR 2 training to move into the Tech 2 range (75m/250 ft with 60 min of deco). 

Costing Out The Options

I started with the actual cost of training, and for me, a Tech 2 class costs $2250. When I calculated the gas costs of a Tech 2 class, I used $1.75 cu ft of 21/35, $1.95 cu ft for 18/45 and $2.15 cu ft for 15/55. This could be much lower than in many places, and these costs are not going down. A typical Tech 2 class with me will see a 45 m/150 ft dive followed by a 60 m/200 ft dive and then a 75 m/250 ft dive. These depths and the times may vary from instructor to instructor, but this is likely a good starting point. 

With the volumes of the various gasses needed, adding three charters for the experience dives, and assuming the class had three students, so the instructor’s charges would be split three ways, I came to an amount just shy of $5,350 for costs needed to complete a T2 class.

In comparison, I then did the same calculations for a CCR 1 class. This included doing some quick math with respect to the cost of the actual CCR unit itself. This is usually the big “Holy Smoke” factor for divers choosing between T2 and CCR 1. The JJ-CCR itself is about $9,000, and then you need to add in the parts and pieces to make it GUE compatible, and by the time the smoke clears, you are looking at about $11,500. [Ed.Note: At the present time, GUE only offers courses on the JJ-CCR in a special GUE configuration.] I assumed you would repurpose your OC regulators that you would have used in your Tech 2 class, so that portion of the costs are a wash. 

Class costs for a GUE CCR 1 class are the same as a Tech 2 class, but associated costs are considerably less. For this reason, the CCR 1 course fee and incidental costs come to $2,970, assuming that the student rents their CCR cylinders, or $2380 less than a Tech 2 class. Thus, your initial outlay to take a GUE CCR 1 class would be in the neighborhood of $14,470.

This means that your choice to take CCR 1 over Tech 2 would require an additional $9120. 

After your CCR 1 course, and 25 experience dives on your JJ-CCR, you will be diving your CCR unit into your original Tech 1 range, with a significant cost savings per dive. One of the biggest benefits of diving a CCR is that gas costs are not that different regardless of whether you chose to dive to 45m/150 ft or 75m/250 ft. This means that, if you wish, every dive can be a technical dive.

In order to compare apples to apples, I wanted to take this one step further and see what the economics were of taking the JJ CCR into the Tech 2 range. Remember that the original choice was CCR 1 or Tech 2, and stopping your CCR training at the CCR 1 level would not give you the knowledge or training to safely dive into the Tech 2 range. There are some significant considerations when moving from the normoxic to the hypoxic range of technical diving, and the CCR 2 class includes much of what was previously taught in Tech 2. 

CCR and OC divers at EDGE 2.0 workshop at Maple Bay, British Columbia.
CCR and OC divers at EDGE 2.0 workshop at Maple Bay, British Columbia. Photo by SJ Alice Bennett

I have written about this before but, in a nutshell, if you have to bail out from a CCR 2 dive, you are then basically an open circuit Tech 2 diver, and you need all the same skills required as a Tech 2 diver, including bottle rotations. Hence the CCR 2 course is considerably more complex because it combines both open circuit and advanced closed circuit hypoxic dive training. 

The prerequisite to CCR 2 training is the requirement to perform at least 50 CCR 1 experience dives with half of them in the Tech 1 range. The good news is that these dives are a lot less costly than an open circuit dive to the same range. Fifty of these dives will cost you about $260 per dive (assuming you need a dive charter and rent cylinders) so at the outside, you will spend $13,000 on these dives. 

Now we need to add back in the cost of the CCR 2 course, and this training— including incidentals—will cost you in the range of $3913. Thus, to take your JJ CCR into the Tech 2 range, you will need the cost of the experience dives and the cost of the CCR 2 course. This will add an additional $16,913 to your initial cost difference of $9120 when you choose the CCR 1 over Tech 1 pathway. In a nutshell: you will need just shy of $26,033 more if you choose to move into the Tech 2 range. However, this would presumably be spent over a year or two.

This seems like quite a significant cost difference at first, and $26,03 is nothing to sneeze at for sure! However, now we need to start looking at what all your future diving is going to look like. 

Using an 18/45 trimix dive to 60 m/200 ft as a baseline “standard T2 dive,” and using all the original costs and volumes I used to calculate the Tech 2 class, I calculated each Tech 2 dive as costing about $731. At the same time, the equivalent CCR 2 dive will cost you about $200, with potentially $60 cylinder rental (ccr and bailout bottles). When the smoke finally clears, you will save about $500 per dive if you do them on your CCR and it would take you only 52 dives to make up your original cost differential! [Ed: Total cost to achieve CCR2 ($31,383) less T2 class cost ($5349)÷ $500/dive] Moreover, since it will really cost you about the same to do a CCR 2 dive than a CCR 1 dive (excluding bailout cylinders), all 52 of these dives can be done exploring some pretty remarkable sites that are outside of the range of the vast majority of divers. 

The assumptions used in the calculations shown above are here:
CCR v OC Calculations

Doing these calculations was quite enlightening. I knew that at some point, it would make sense to choose CCR over OC for technical diving, even given the higher costs to “buy in” to CCR training, but I didn’t honestly realize that the break even point for a diver who chose the CCR 1 and CCR 2 pathway as opposed to the Tech 2 pathway would need only 52 dives to make back their investment!

The assumptions used in the calculations shown above are here: 
CCR v OC Calculations

There are a few other things to consider after your T2 or CCR 1 training also. 

Other Considerations

As I mentioned above, one of the coolest things about CCR diving is understanding that your oxygen use is independent of depth. It is a function of your metabolism, and it doesn’t matter how deep you decide to dive. The only factor that needs to be considered with respect to depth is the amount of diluent you need for your loop volume, the amount of bailout gas you need, and drysuit inflation. What this means when the rubber hits the road, is that every dive can be a tech dive where you are exploring outside the limits of the recreational diving realm! For me, this was a huge consideration: I wanted to see what most divers were not able to see, and this meant diving past the normal recreational limits. Basically then, my de facto technical diving increased substantially because cost was no longer such a limiting factor. All my “fun” dives could be technical dives!

From a logistical point of view, unless you need to use your bailout deco gas, the only gas you will need to use there is what is wasted during gas analysis! This means that your bailout deco gas lasts a longgggg time! This also helps when it comes to, “How many cylinders do you need to carry on the boat?” You can do a lot more diving with fewer cylinders, and this is not something to ignore when talking about T2 level dives!

I live in the Pacific Northwest, and the water temperatures here can be challenging depending on the time of year. There is absolutely no question that I am warmer when diving on my CCR. The air I am breathing is warmer and is not as dry. I most definitely notice this and stay warmer in colder water. 

Is There a CCR In Your Future?

Helium costs continue to rise, and availability is becoming more of a problem every day. This means that the break even point continues to come sooner, and the follow-on costs become more significant. This means that in our current world, for those with a desire to explore in the technical diving range, the decision to choose the CCR 1/CCR 2 pathway versus the T2 pathway becomes more straightforward!

There are several things to consider when deciding whether to choose the CCR or OC pathway past T1. Costs, logistics, helium availability—now and in the future—are just part of this equation. 

I think the CCR 1 pathway is likely the most pragmatic choice, but this requires a healthy initial investment and an understanding that you will likely need to complete CCR 2 down the road to have access to the deeper depths that T2 unlocks. There are a lot of considerations involved when entering the hypoxic gas realm and the associated skills required if things go sideways on these deeper dives. Frankly, I get a little nervous when I see divers moving into these deeper ranges with no CCR training specific to these depths. “You don’t know what you don’t know” is a very real consideration here. 

CCR 1 is likely the way of the future. The benefits are clear, and it unlocks many aspects of technical diving that fit well with our GUE exploration world. I have personally seen an increase in CCR students after T1 and look forward to seeing our technical world grow and evolve!

To Be, or Not to Be a CCR Diver: How I made the Choice

InDEPTH asked new technical or CCR divers to tell us how they went about making the decision as to when and why to make the switch from open circuit. Here’s what they told us: To Be, Or Not To Be

Dive Deeper

InDEPTH: GUE and the Future of Open Circuit Tech Diving by Ashley Stewart

QUEST: CCR LEVEL 2 Enters The World by Guy Shockey

InDEPTH: The Thought Process Behind GUE’s CCR Configuration by Richard Lundgren

InDEPTH: Can Mouthpiece Retaining Straps Improve Rebreather Diving Safety? by Reilly Fogarty

Guy Shockey is a GUE instructor and instructor trainer who is actively involved in mentoring the next generation of GUE divers. He started diving in 1982 in a cold mountain lake in Alberta, Canada. Since then, he has logged somewhere close to 8,000 dives in most of the oceans of the world. He is a passionate technical diver with a particular interest in deeper ocean wreck diving. He is a former military officer and professional hunter with both bachelor’s and master’s degrees in political science. He is also an entrepreneur with several successful startup companies to his credit.

Enjoying InDEPTH? Consider buying us a coffee so we can continue to provide you with insanely great content!


InDepth’s Holiday Rebreather Guide: 2022 Update

Making a list. Checking it twice. Gonna find out which breathers are naughty or nice. That’s right! It’s time again for InDEPTH’s Holiday Rebreather Guide.
This year, the Guide features 28 models of back, chest, and side-mounted rebreathers, including two new entries, for your shopping operation. So, get out your pre-buy checklist, and that gift certificate and start ogling your loop of your fancy. Ho ho ho!




InDepth’s Holiday Rebreather Guide: 2022 Update

by Michael Menduno, Amanda White and Kenzie Potter

Holiday images by Jason Brown, BARDO CREATIVE

A Guide to Backmount, Sidemount and Frontmount Rebreathers

1DEC 2022—Ho ho ho! Once again, we have updated InDEPTH’s Holiday Rebreather Guide adding two new rebreathers; the new Gemini sidemount, needle valve mCCR from Fathom Systems, and the Generic Breathing Machine (GBM) front mounted, needle valve mCCR, with a dive computer-compatible, solid state oxygen sensor from Scubatron. We also updated the features on the Divesoft Liberty sidemount, and the JJ-CCR. This year, Vobster Marine Systems was acquired by UK-based NAMMU Tech, which plans to rename and re-issue a version of the VMS Redbare. See link below.

Finally, Innerspace Systems’ founder Leon Scamahorn agreed to work on getting us the needed information to add the storied Megalodon to the Guide. Scratch last year’s coal, Xmas cookies for you Mr. Scamahorn! Happy holidays shoppers, here is our updated rebreather guide! Mind those PO2s!

17DEC2021: Ho Ho Ho! We have updated our Holiday Rebreather Guide with new rebreathers and updated features. Despite repeated requests, the only major closed circuit rebreather we are missing is Innerspace Systems’ Megalodon and its siblings. Tsk, tsk Leon Scamahorn, you’ve been a naughty boy! Behold, here is our updated guide. Mind those PO2s!

Sport diving rebreathers have come a long way since storied explorer Bill Stone trialed his 80 kg/176lb fully-redundant “Failsafe Rebreather For Exploration Diving” (F.R.E.D.), and spent a cool 24-hours underwater as part of his paradigm-shifting 1987 Wakulla Springs Project. In retrospect, looking back over the last 30-some years, the “Technical Diving Revolution,” which emerged in the late 1980s to late 1990s, was ultimately about the development and adoption of rebreather technology. 

Dr. Bill Stone’s manned trial of F.R.E.D. at Wakulla Springs (1987). Photo courtesy of the US Deep Caving Team

However, it took the fledgling tech community at least a decade to adapt mixed gas technology for open circuit scuba, including establishing the necessary supporting infrastructure, which was the first and necessary step in the move to rebreathers. A little more than a decade after Stone showcased FRED, British diving entrepreneur Martin Parker, managing director of then AP Valves, launched the “Buddy Inspiration,” the first production closed circuit rebreather designed specifically for sport divers, earning him the moniker, the “Henry Ford of Rebreathers.” [The brand name later became AP Diving] KISS Rebreathers followed a little more than a year later with its mechanical, closed circuit unit, now dubbed the KISS Classic. The rest as they say, is history, our history. 

Buddy Inspiration advertisement from 1998. Courtesy of AP Diving.

Today, though open-circuit mixed gas diving is still an important platform, rebreathers have become the tool of choice for deep, and long exploration dives. For good reason, with a greatly extended gas supply, near optimal decompression, thermal and weight advantages, bubble-free silence, and let’s not forget the cool factor, rebreathers enable tech divers to greatly extend their underwater envelope beyond the reach of open circuit technology. 

As a result, divers now have an abundance of rebreather brands to choose from. Accordingly, we thought it fitting this holiday season to offer up this geeky guide for rebreather shoppers. Want to find out whose breathers are naughty or nice? Here is your chance.

Your Geeky Holiday Guide

The idea for this holiday guide was originally proposed to us by Divesoft’s U.S. General Manager Matěj Fischer. Thank you Matěj! Interestingly, it doesn’t appear to have been done before. Our goal was to include all major brands of closed circuit rebreathers in back mount and sidemount configuration in order to enable shoppers to make a detailed comparison. In that we have largely succeeded. We  also included Halcyon Dive Systems’ semi-closed RB80 and more recent RBK sidemount unit, which are both being used successfully as exploration tools. 

Absent are US-based Innerspace Systems, which makes the Megalodon and other models, as well as Submatix, based in Germany, which manufactures the Quantum and sidemount SMS 200, neither of which returned our communications. M3S, which makes the Titan, declined our invitation to participate, as they recently discontinued their TITAN CCR—they will be coming out with a replacement unit, the TITAN Phoenix CCR in the near future. We did not include the MARES Horizon, a semi-closed circuit rebreather that is aimed at recreational divers. No doubt, there may be brands we inadvertently missed. Our apologies. Contact us. We can update.

Update (22JUL2021): French rebreather manufacturer M3S contacted us and sent us the specs for their updated chest-mounted Triton CCR, which are now included in the guide.

Update (9DEC2020): Submatix contacted us and the Guide now contains their Quantum (back mount) and SMS 200 (sidemount) rebreathers. We were also contacted by Open Safety Equipment Ltd. and have added their Apocalypse back mounted mechanical closed circuit rebreather.  We will add other units as they are presented to us by the vendors. 

It’s The Concept, Stupid

The plan was to focus on the feature sets of the various rebreathers to provide an objective means to compare various units. But features by themselves do not a rebreather make. As Pieter Decoene, Operations Manager at rEvo Rebreathers, pointed out to me early on, every rebreather is based on “a concept,” that is more than just the sum of its features. That is to say that the inventors focused on specific problems or issues they deemed important in their designs; think rEvo’s dual scrubbers, Divesoft’s redundant electronics, or integration of open and closed circuit in the case of Dive Rite’s recently launched O2ptima Chest Mount. Shoppers, please consider that as you peruse the various offerings. My thanks to Pieter, who helped us identify and define key features and metrics that should be considered.

Though not every unit on the market has been third-party tested according to Conformitè Europëenne (CE) used for goods sold in the European Union, we decided to use CE test results for some of the common feature benchmarks such as the Work of Breathing (WOB), and scrubber duration. For vendors that do not have CE testing, we suggested that they use the figures that they publicize in their marketing materials and asked that they specify the source of the data if possible. As such, the guide serves as an imperfect comparison, but a comparison nonetheless.

Santa’s Little Helper: Meet Rufus, BARDO’s Chief Muse Officer (CMO)

Also, don’t be misled by single figures, like work of breathing or scrubber duration as they serve only as a kind of benchmark—there is typically a lot more behind them. For example, whether a rebreather is easy to breathe or not is a function of elastance, work of breathing (WOB) and hydrostatic imbalance. In order to pass CE, the unit must meet CE test requirements for all three issues in all positions from head down, to horizontal trim, to being in vertical position (Watch that trim!), to lying on your back looking upwards. It’s more difficult to pass the tests in some positions versus others, and some units do better in some positions than others. 

The result is that some of the feature data, like WOB, is more nuanced than it appears at first glance. “The problem you have is people take one value (work of breathing for instance) and then buy the product based on that, but it just isn’t that simple an issue,” Martin Parker explained to me.  “It’s like people buying a BCD based on the buoyancy; bigger is better, right? Wrong! It’s the ability of the BCD to hold air near your centre of gravity determines how the BC performs. With rebreathers you can have good work of breathing on a breathing machine only to find it completely ruined by it’s hydrostatic imbalance or elastance.”

Due to their design, sidemount rebreathers are generally not able to pass CE requirements in all positions. Consequently, almost all currently do not have CE certification; the T-Reb has a CE certification with exceptions. However, that does not necessarily mean that the units haven’t been third-party tested. 

Note that the guide, which is organized alphabetically by manufacturer, contains the deets for each of their featured models. In addition, there are two master downloadable spreadsheets, one for back mounted units and one for sidemount. Lastly, I’d also like to give a shout out to British photog phenom Jason Brown and the BARDOCreative Team (Thank you Georgina!), for helping us inject a bit of the Xmas cheer into this geeky tech tome [For insiders: this was Rufus and Rey’s modeling debut!]. Ho, ho, hose!

With this background and requisite caveats, we are pleased to offer you our Rebreather Holiday Shoppers’ Guide. Happy Holidays!!

Ed. note: Most prices shown below were specified by manufacturer before tax.

Backmount Rebreathers

* In 2005, AP Diving launched its Vision electronics with In-Plane Switching (IPS) which enhances colour and visibility
**Typical scrubber duration using AP Tempstik increases practical duration to more than double CE test rate figures – as the AP Tempstik shows scrubber life based on actual work rate, water temperature and depth.
*** The work of breathing is the effort required to push gas around the breathing circuit BUT that figure alone is meaningless without knowing two other parameters: Hydrostatic load and elastance. Note that AP Diving rebreathers meet the CE requirements in all diver attitudes for both Hydrostatic Imbalance 0 degrees (horizontal, face down) and Hydrostatic Imbalance +90 degrees (vertical, head up.)
**** APD’s handset offers a “dual display” feature showing data from both controllers on the same handset. The user can also see the gradient factors chosen and the mVolt outputs of the cells by holding a button down.
* Divesoft will offer an upgrade for existing Liberty users

* Note that we plan to re-release our “Intervention CCR” (iCCR) in 2021. The unit was withheld due risk of loop being force dived when unsafe (pending re-release 2021).This enables the diver the option to manually trigger bailout to a known safe OC gas at any time with one finger and/or auto-bailout the diver if loop gas being breathed reaches unsafe level. Either Hi/Lo PPO2 or high End-Tidal CO2.
**For CE certification the recommended Apocalypse Type IV CCR scrubber duration is 2hr 45min to a maximum dive profile surface to surface of 100m in 4’C water to 2.0% SEV (20mb) at the mouth.
***iCCR (2009) 3x digital galvanic coax, iCCR (2021) x2 galvanic 1x solid state
****All performance data near near identical to single scrubber option other than increased scrubber duration of up to 5 hrs to 100 m profile in 4’C water)
Published Testing: .pdf
* CisLunar series, MKVI 2009, SE7EN 2013, SE7EN+ 2019
** 40 m coldwater EN14143
*** Backmounted Trimix 10/70, 40M test: Backmounted Air
**** SE7EN+ Sport EU incl (harness, wing, computer, cylinders and sensors)

NOTE: Vobster Marine Systems were acquired by UK-based NAMMU Tech, which plans to rename and re-issue a version of the VMS Redbare (formerly the Sentinel) at some point in the future. See: Atlas CCR


Rey says he’s sticking to open circuit. What’s a Santa to do?

Sidemount Rebreathers

*Pre 2021 units are upgradebale
* For a tour of KISS rebreathers see:

Frontmount Rebreathers

*Tested with standard DSV, 6l OTS counterlungs, Upright/face forward, 40 m depth, 40.0 lpm RMV, Air diluent
**Tested with standard DSV, 45° head up/feet down orientation, 40 m depth, 40.0 lpm RMV, Air diluent
*** Micropore ExtendAir Cartridge:
180 liters of CO2 @ < 50 deg F [<10 C] (130 minutes @1.35lpm CO2)
240 liters of CO2 @ 50-70 deg F [10-20C] (180 minutes @ 1.35lpm CO2)
300 liters of CO2 @ >70 deg F [>20C] (220 minutes @ 1.35lpm CO2)
Test Parameters: 40 lpm RMV 1.35 lpm CO2130 fsw (40 m) depth Granular duration may be similar, but can vary greatly depending upon the type of granular and packing technique

 Download our two master spreadsheets, one for back mounted units and one for sidemount to compare rebreathers.

Special thanks to Amy LaSalle at GUE HQ for her help assembling the feature spreadsheets.

  • Buddy Dive Bonaire

Michael Menduno is InDepth’s editor-in-chief and an award-winning reporter and technologist who has written about diving and diving technology for 30 years. He coined the term “technical diving.” His magazine aquaCORPS: The Journal for Technical Diving (1990-1996), helped usher tech diving into mainstream sports diving. He also produced the first Tek, EUROTek, and ASIATek conferences, and organized Rebreather Forums 1.0 and 2.0. Michael received the OZTEKMedia Excellence Award in 2011, the EUROTek Lifetime Achievement Award in 2012, and the TEKDive USA Media Award in 2018. In addition to his responsibilities at InDepth, Menduno is a contributing editor for DAN Europe’s Alert Diver magazine and X-Ray Magazine, a staff writer for, and is on the board of the Historical Diving Society (USA)

Amanda White is the managing editor for InDepth. Her main passion in life is protecting the environment. Whether that means working to minimize her own footprint or working on a broader scale to protect wildlife, the oceans, and other bodies of water. She received her GUE Recreational Level 1 certificate in November 2016 and is ecstatic to begin her scuba diving journey. Amanda was a volunteer for Project Baseline for over a year as the communications lead during Baseline Explorer missions. Now she manages communication between Project Baseline and the public and works as the content and marketing manager for GUE. Amanda holds a Bachelor’s degree in Journalism, with an emphasis in Strategic Communications from the University of Nevada, Reno.

Kenzie Potter Stephens is a production artist for InDepth as well as part of the GUE marketing team. She earned her BS degree in Industrial Engineering and Marketing at the Karlsruhe Institute of Technology (KIT) in Germany, which assists her in using her multicultural upbringing to foster international growth within the community. In addition to her activities as a yoga teacher and an underwater rugby trainer, she has completed her GUE Tech 1 and Cave 1 training and is on her way to becoming a GUE instructor. Not letting any grass grow under her feet, she has also taken on a second major in biochemistry in order to create a deeper understanding of our planet’s unique ecosystems as well as the effect of diving on human physiology.

Continue Reading

Thank You to Our Sponsors

  • BuddyDive Bonaire


Education, Conservation, and Exploration articles for the diving obsessed. Subscribe to our monthly blog and get our latest stories and content delivered to your inbox every Thursday.

Latest Features