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Would you like to get into CCR diving?

Written by farkasdo

09/12/2021

The best rebreather

The hardest part is the first step: Which unit??

There is a lot of debate, which one is the best rebreather in the market. What I have found: There is no such thing. There are many good and very good units but I can give you a detailed opinion on the one which I am using.

The popularity of rebreathers is growing exponentially between divers. This also means that there is a wide range of units to choose from. It is a big investment, therefore you want to be careful with your decision when picking which unit would you go for.

Well, here is some news for you.

There is no “Best CCR”. It is like which regulator is the best. Or which ski? It depends on many factors. Where you would like to use it. What diving are you doing?

revo rebreathers malta

 

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It also depends on you. How tall/strong are you? Do you travel a lot, or will you dive it more locally? Are you diving in open sea/lake or super tight caves? Do you need an expedition unit if your diving is mainly for photography above 40metres? Where can it be serviced? How long does it take to get spare parts? Are other divers in the area using the same machine, so you can get advice/spare bits? Who is the instructor? Would you like to do the course with that person?

Why did I choose rEvo?

I went through these questions myself, and in the end, I decided on rEvo.

What advantages did I find?

Working as a support diver, I always loved divers with rEvo, the unit is light! (It is very compact, barely any additional weight is needed, so even when it is set up, they are easy to lift and move around.) The square shape also makes it easy to pack in a car/truck.

Then, on to diving. Field of vision. Since the unit and the lungs are behind you, there is no “T-piece” next to your face which would restrict your head movement or how wide is your vision sideways.

revo rebreather malta

What about CO2?

Probably the most discerning feature is the dual scrubber with temperature sensors. One of the biggest dangers with CCR diving is CO2 breakthrough. Packing 2 scrubbers automatically halve what is already a low possibility, making the unit safer even if one of the scrubbers is not perfectly packed. Also, it is easier to pack smaller volumes. On top of that, the unit will tell you if anything is wrong with the scrubber!

revo dual scrubber

Normally, other rebreathers give you 3 hours with 2.6-3 kg sofnolime. With rEvo you can dive at least 3 hours with half of that (1.35 kg lime) and with the advanced rMS (temperature monitoring system) you will likely be able to dive even longer while being completely safe. No stress about how long will your scrubber last because it literally gives you remaining time in minutes (actually hours). I really love that feature!

The number of sensors.

On a rEvo one can run up to 5 sensors. You don’t change them all at once, but in a rotation, so the chance that they fail all at the same time is practically zero. I thought having 5 sensors costs more but literally, I don’t spend more changing them according to factory recommendation one in every 6 months. Tempting much?

The rEvo is a hybrid CCR, enjoying the benefits of both manual and electronic CCRs.

It has a continuous O2 flow which you set to your metabolism, so at constant depth there is nothing to do, your O2 partial pressure remains constant. Meanwhile, the electronics keep the ppO2 at the set level with any changes. This makes the rEvo a very easy to use and relatively simple CCR.

How can one fit for all?

The 3 different sizes give a selection for taller/smaller people, however, I have seen pretty tall people diving comfortably with the micro.

revo rebreathers malta

Backup systems:

The general rule in CCR diving is that you need at least 2 independent systems monitoring your ppO2 at all times. In other units, this is usually solved with a handset controller/computer and a HUD (Head up display) showing the ppO2 readings in parallel.

shearwater Nerd computer for revo shearwater divecan rms controller revo dream

In rEvo, each HUD can show 1 or 2 cells, and if you are running 5 cells, even in case of connection error or failure, the chance that you don’t have at least 2 cells to compare is effectively zero! (unless you flood the unit. Don’t do that. That is expensive.)

Is this unit perfect then?

This is the only disadvantage that I have heard from divers about the unit. The flood tolerance of the unit is quite low, there is no dump valve other than the OPV. True.

However, the amount of parts to be assembled is so small, and if they leak, you will notice it (and fix it) at the predive check.

Hence, the only real way to flood a rEvo is to take the open mouthpiece from your mouth, which in truth will flood any unit. Simply don’t do that.

How can a rEvo save your dive?

Basically, the Expedition versions from the factory come with 3 independent displays with which you operate the machine. The displays will be your choice of handset/ HUD/ Nerd. Finding yourself in a remote area or a liveaboard, if any one of these systems fails, you simply continue diving, while still retaining two independent systems.

Cables, sensors are all accessible, so they are quick and easy to fix locally (Yes, we can do that for you). The only time you would need to send the unit to the main service centres is for the 5 or 10 years’ service.

revo adv and solenoid board

And last is the flexibility: If you don’t like any of the features, you have a choice. It is not simply a hybrid unit. You can easily convert between manual, hybrid, or simple electronic CCR, and your choice of using 3, 4 or 5 sensors.

Summary:

I am not a CCR expert, and neither have I dived all the machines available. When the occasion came along, I took the chance to try the JJ and an expedition grade Hammerhead, however, I am still happy with my choice.

As I said, there is no perfect unit. But the rEvo is very close to it, at least for me.

If you are interested to become a rEvo diver or even a trial dive, send me a message, I would love to hear from you!

Here you can learn more about the CCR course itself.

TDI revo course malta

Instructors saying about rEvo

13 years with rEvo and 3000 dives. Never flooded the unit. Once I had to call the dive on the surface because of the pinched lid o-ring but was easy to fix. Once had to bail out and the reason was that DSV knob was loose and it started to leak water in. Got tired of emptying the loop all the time.
More flood recoverable units usually end up having T pieces on the loop to have a water trap and several more connections with O-rings. In my experience, those are often failure points and the more you have O-rings more leaking points there are. Some engineer once said: “when designing skills end, you put an O-ring”. I rather have a machine with fewer failure points than better flood recovery. Often your electronics are gone at that point anyway and you need to bail out.
Personally, I use Petrel+NERD+BOV and can’t think of anything I would need to be changed. Maybe a more robust lid, it tends to scratch easily when squeezing through restrictions in caves, mines and wrecks.
Jani Santala

Owner of Visit Plura

When I started diving rebreathers, you did all of your checks, then did them again. Before each dive, you text your kids (no Facebook or social media then) and tell them that you loved them. I searched for a reliable rebreather. Inspiration, then Evolution vision. Megladon, Kiss, Sentinel then rEvo. I tried a JJ when they came out but it wasn’t better than the rEvo. I was one of the recipients to receive an Apocalypse and after all of the hype the rEvo still remained the best unit that I’d owned. I’ve seen and tried plenty of the new breed of rebreathers but the rEvo is in my opinion the unit that will not let me down. Sure there have been some issues with the rEvo but minor ones and I’ve always known that I’m coming back. Thousand of dives on different units and I’ve never once had a unit flood. The Sentinel was said to have flood recovery and we tried it. You would be insane to dive that unit after a flood. I’ve seen a rEvo flood, a non CE rEvo 2 with an Apeks drysuit shoulder dump valve installed for flood recovery. It caused floods instead of de-watering a unit.The rMS was a bit flakey at first but has been stable for the past 5 years.

If there was a better unit, I’d own it.

 
Simon Taylor-Watson

Owner Tekdeep.com

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