CCR or not to CCR? Now that is the question.

CCR OR NOT TO CCR, I often get asked the question from technical divers whether they should go the no bubble way.

So should you or not? I thought I’d put down my two cents worth and get some of the pros and cons out of the way.

1) Price Tag of the CCR:

Take it or leave it; a closed circuit rebreather, CCR, is an expensive piece of equipment and it should also be handled like that. Depending on currencies and import duties you are looking at 6,000-15,000US$ for a closed circuit rebreather.

Where does this ridiculous price come from and what’s the difference? You should know that there are 3 types of rebreathers; the semi closed rebreather, SCR, injecting a chosen gas at a set rate into a breathing system. This is a safe choice as mechanics and electronics are limited and so is the price.

Then there are the manual closed circuit rebreathers. These units are just like the semi closed units based on a constant flow (regulated my an injection nozzle, or mass flow orifice) but this time it is pure oxygen instead of your bottom gas.

Oxygen can kill you when levels are too high or too little, hence, a close monitoring is crucial. Monitoring is established through 1-3 oxygen sensors giving a signal to a submersible handset, giving you the partial pressure oxygen readings of what goes actually into your lungs. The diver can then choose to manually inject more oxygen should a higher partial pressure of oxygen be desired. The injection nozzle is just there to keep survivable oxygen content in case the diver forgets to manually add oxygen. These units, or manual CCR’s (MCCR) are a bit more expensive than the semi closed rebreather because of the electronics. Plenty of divers add a second monitoring system as redundancy or an inline decompression computer that adds monitoring redundancy whilst giving on the fly decompression requirements readouts.

The last family is the ECCR or electronic rebreathers. The diver chooses a pre-set oxygen partial pressure and the unit maintains that specific pressure, called a set point. This requires again electronics and a solenoid valve, a small electronic gas valve, which adds small bursts of oxygen to maintain the set point. Because the user now totally relies on electronics, these units always have redundant displays. In case of malfunction, the user can still ‘fly’ the unit manually. Like the MCCR’s , many CCR divers replace the secondary handset with an inline decompression computer which acts as oxygen monitor and decompression computer.

2) Dive Price once you have the CCR:

Once you’ve bitten through the bullet of buying a machine, it won’t dive by itself. Just like an expensive racecar, it needs some ingredients to run.

The ingredients are:

• 1 tank of oxygen
• 1 tank of diluent (bottom gas, can be air or a helium mixture for deeper dives)
• quantity of carbon dioxide absorbent. This is the chemical, which will ‘scrub’ the co2 out of your exhaled breath so it can be re’breathed after the machine added the oxygen you’ve just used.

An oxygen fill can cost anywhere between 5 and 15 dollars. The tanks are small and depending on the type of diving you do you can spent one to 3 dives on one tank. The same goes for the diluent tank. Air is cheap and a fill can cost you between 3-10 dollars. The helium will cost far more (see below)

The chemical, scrubber, is not cheap either; 2pounds or 1kg will cost you around 10$ and most units hold between 2kg and 4 kg (4-8LBS). A rough figure is around 1 hour per kg of scrubber material. So, just like with the tanks, this should be refilled after a day of diving

And then you’re not even on the dive boat yet… most operators will not give you a discount because you’re not breathing as much gas as the open circuit divers. You might as well take full advantage of this and take a bail-out tank with air since it’s paid for anyways and rebreather don’t always function like they should

3) Diving the CCR:

So, adding all the costs up, you’re looking at 65USD for just your CCR supplies on that 5 star liveaboard plus your diving. If you are fortunate and can buy all of those at cost price, this figure can drop to 30$ for your 3-day dive day, still more expensive than open circuit.

Preparing a CCR is not as straightforward as strapping a BCD and a regulator to your scuba tank. Just like a plane, there is an entire checklist a diver needs to go through, setting up his unit. Novice CCR divers will easily spent an hour prepping their unit for the day, while seasoned CCR divers might be able to do this in 20minutes. Prior to every dive, a brief checklist needs to be adhered to as well, taking again 5-10minutes. Failure to do so has resulted multiple times in death, even with experience CCR divers. Complacency kills!

4) Legal issues:

If you are teaching open circuit divers or simply diving alongside open circuit divers, the first thing you need to ask yourself, is if you can help them in case of an out of air emergency. Obviously you have though about your own bail out options should your unit fail. But is there enough of this to help a buddy CCR diver or an open circuit diver?

This is one of the reasons why it is not allowed by many agencies to dive a CCR while guiding or teaching other open circuit divers; simply because they might be confused of what gas source to breathe from when they are hanging all stressed out in front of you, giving the out of air sign.

When diving as a dive professional in European waters, there is the CE tag. Half of the CCR’s today on the market have put the time and money to obtain that CE mark, allowing CCR instructors to wear their unit during their profession. Check it out if that is your scope

5) Trimix and CCR:

Plenty of Trimix divers ask me if it is cheaper to dive a CCR on Trimix rather than on open circuit. Yes it is…

But only in the long run. If you’re a weekend diver and planning on purchasing a CCR just to save on helium costs, then don’t. The training required, the number of dives and the cost of a unit well outweigh the few hundred dollars spent a year on helium.

If you are normally diving a 80’s twinset with a 50% helium mixture, then you would save around 100USD per dive. As a rough figure, you would need a 100 Trimix dives to have a break even. This does not take into account the training (+/-5000USD) and the spare parts, excess weight when traveling and your bail out gasses, which many will dispute that they are re-useable. Try telling the local dive shop in Egypt to keep your stage bail out gas until next year.

So why dive a CCR, rebreather?

Simply because, once you get through the training and the endless adjusting and fine tuning, a CCR gives you a tremendous feeling of freedom; the bubbly noise is gone, you’re breathing warm moist air as opposed to cold dry gas, you have a seemingly endless gas supply and you know that your machine is mixing for you the perfect mix at every depth, allowing for a maximum bottom time with no or limited decompression requirements. The high partial pressure of oxygen in the shallows will leave you feeling les tired and less dehydrated after diving.

The lack of noise from the bubbles and regulator will let marine life get closer to you.

Lastly, if an o-ring blows out of your open circuit scuba tank; you have a few seconds left to either locate your buddy or start heading towards the surface before gulping down your last breath. In case of total gas loss, a CCR will leave you quite a bit of time before the levels in the breathing system drop to a dangerous level. But the again, if you take the loop out of your mouth, it will fill up with water, rendering the unit useless.  Some systems now have a drain valve, so limited amounts of water can be drained in case of a flood.

So, to CCR or not to CCR?

Diving CCR needs serious dedication, on a financial level, training level, bit also afterwards on maintenance and discipline level. The rewards are there, although you might not appreciate them in the beginning, since the first dive on a CCR will leave you feeling as an absolute novice diver with limited buoyancy skills… Still, I believe CCR’s are the way forward into diving and the future of technology will make safer and more reliable humans, sorry CCR’s

Ben Reymenants, Megalodon Air Decompression Instructor Trainer and Trimix Instructor Trainer

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