Just tried 3 CCRs (Fathom, rEvo, Choptima)

[sylverbard]

First of all, a huge thanks to Ben Lair from Paragon Dive Group (@DiveTucson ) for helping me test the rEvo and Choptima today!

Keep in mind, I'm still a newb, so take what I write below as just personal notes for myself; which shouldn't be used as any type of authoritative information for comparison, etc.

Yesterday Fathom did a try dive, which I've been looking forward to for months. Charlie, the owner of Fathom, did a complete build from start to finish at which point we had a choice of diving a "cave" or a "tech" setup. Cave setup being lighter, more compact, with the DIL/BO being offboarded (side-mount). While the tech rig (assembly of which is pictured below) has DIL/BO in the form of dual LP50's attached directly to the CCR.

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I wanted to try the tech setup, as that's most likely the configuration I'd choose diving off of a boat, but as I knew I'd be testing other units, I wanted to be fair to Fathom and not unfairly compare such a heavy/loaded rig to lightweight setups.

We were given some instruction on how to dive the CCR and under Charlie's and Jon Bernot (Instructor Trainer and owner of Cave Country Dive Shop) we descended to the 20ft platform at Blue Grotto and swam/experimented at that depth for about 20-minutes, then we went down to the 35ft platform, swam around there for another 12-minutes and then slowly made our way back up. Total dive length was 36 minutes and was my first time ever trying a rebreather. What an experience!! I'll save the details of learning how everything works, but as everything is manual, there were no nannies doing things for me. Had to learn quickly!

The unit instantly trimmed out perfectly and once I figured out how to establish proper loop volume I was able to breathe properly. I also played around with the needle valve and quickly dialed it in for my gas consumption. Our goal was to hold a ppo2 of 1.3 and after initially overshooting it a bit, I dialed it back and found a sweet spot which landed me at 1.3 without touching the O2 MAV. It also took at least 15-minutes to dial in buoyancy to a point where I wasn't constantly kicking to maintain it.

My thoughts are that it's a very nice unit with high quality parts and high degree of craftsmanship. The unit can be configured in a ton of different ways and no detail is overlooked. Up to a 9lb radial scrubber, fully potted electronics, BMCL, BOV w/DILOUT, etc. The Fathom HUD is amazing!! In trim the WOB is phenomenal, but head down it was harder. I thought head movement was a little restricted and wasn't sure if it's because of the BOV (hose) or just being new to CCR. In general, anyone looking for the highest quality manual CCR can't go wrong with this unit.

Here's what I dove:
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Today I met up with Ben Lair (@DiveTucson) in Ginnie Springs, who offered to let me try dive his Optima CM (Choptima) and my buddies rEvo Mini. We started with the rEvo. We replaced the steel tanks with aluminum and I pulled out all the weight from the upper pouch. I didn't need the additional weight with my wetsuit. We set the setpoint to 0.7 (just in case), but my goal was to maintain a 1.0 and fly manually. Similar to the Fathom, the unit instantly trimmed out well, the breathing was very good but slightly different and unlike the Fathom the WOB was more consistent whether I'm pointing straight up or down. There were a lot more noises and just like the Fathom I had to essentially learn how to dive this unit. ADV on it is disabled. The overall package was relatively light on my back and I carried an AL72 for BO.

I really like the overall all-in-one package, super easy to set up, no extraneous hoses, connections, T-pieces, etc. Very clutter free, put on and go. The range of motion seemed better here.

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Last, but not least, we attached Ben's Choptima to my double HP100's.... not quite the standard config, but that's one of the beauties of Choptima... add it to whatever you want. Ran it with just a NERD, no wires or computer on the wrist - felt almost naked for a minute there, but the NERD is super nice!

Choptima had an ADV on/off, so I got to experiment with that. After a few minutes of back/forth I believe I prefer that to be off - allows me to better manage loop volume and doesn't screw up my buoyancy without me knowing. The Choptima breathes well but is the complete opposite of the rEvo. It was harder to exhale and easier to inhale. In fact, I always felt like the gas was rushing into my mouth (chipmunk cheeks), but I'm certain that's just because I don't know how to maintain ideal loop volume, etc. Similar to the rEvo, it was a little more consistent in WOB in various orientations, but obviously going inverted it breathed more like a rEvo. I understand what people mean about chest clutter now, but also believe that's something I'd be used to. I noticed when hovering just a few inches off the bottom at times I'd feel the bottom (not used to the additional equipment there). Didn't have issues with trim with this unit either, but I definitely felt a little pregnant. Was very interesting to feel the lungs expand and contract as I breathed in and out. Last but not least, (I believe) it seemed to give my head the most range of motion.

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So all-in-all, an excellent adventure! I learned a lot. CCR diving is hard!! I spent 1.5-hours in the water on three different units and I still had the reflex to try and inhale to slow descent and exhale to slow ascent, etc. Will have to completely relearn how to breathe and how to maintain buoyancy. I'm able to dial it in just right but you move a couple of feet up or down and everything changes. Much more sensitive than I thought it would be, but it could be just me

Regarding the units, they were all great and it's clear that the unit should be chosen based on the manufacturers philosophy (matching divers') and ultimate mission. I'm very torn about which unit I'll get, but one thing I learned is I definitely prefer eCCR - at least at this stage. When I hot-drop to a deep wreck I really want an ADV and for the computer to maintain my ppo2, at least until I get to the wreck, then I can fly manually if needed. I definitely like the NERD, the information is just all right there without obstructing my vision. I reserve the right to do a complete 180 in the future, after I actually learn how to dive properly

Now I just need to figure out what I value more:
rEvo - an easy to maintain unit with no clutter, easy to don and jump off a boat and separate BO, or
Choptima - easy to travel, can be added to any type of diving I may choose to do in the future, etc

There are many more pros/cons I didn't list... this isn't meant to be a comparison of the three units. As I said before, I'm not qualified to compare anything at this point. I'm sure when I get more experience the things I'll be comparing (or caring about) will be completely different.

great review.

the acid test: which one do you want to put on and dive for 2 hours ?

 

[boriss]

great review.

the acid test: which one do you want to put on and dive for 2 hours ?

Thanks!

Who's paying? Only kidding - I'd dive any one of them for 2-hours. They were all great, but have different philosophies.

I'd also like to stress that this wasn't a review as much as just my opinion/notes. Now that I've spent more time on the loop my opinion has evolved. I don't want to edit the original post, but in hindsight I've learned I'm wrong about certain things.

For example, I said I had "chipmunk cheeks" with Choptima and that was a result of being chest mounted and it being harder to exhale instead of inhale. Well that's just wrong, this was 100% a result of improper loop volume. Now that I know how to maintain proper loop volume, it breathes so naturally.

I also talked about how hard it is to maintain buoyancy; it's actually incredibly simple and the CL's do most of the work. I almost feel like the buoyancy is more stable compared to OC.

I'll be doing more comparisons with my friends CCRs. Something tells me I'm going to end up with.... more than one CCR...

 

[sylverbard]

For example, I said I had "chipmunk cheeks" with Choptima and that was a result of being chest mounted and it being harder to exhale instead of inhale. Well that's just wrong, this was 100% a result of improper loop volume. Now that I know how to maintain proper loop volume, it breathes so naturally.


I'll be doing more comparisons with my friends CCRs. Something tells me I'm going to end up with.... more than one CCR...

heh, yeah, that difficult to inhale didn't make much sense.

tell you what: to ease the burden of choice, I suggest one of the unist be a rEvo and I will happily babysit it and keep it current while you dive another unit

 

[mr_v]

heh, yeah, that difficult to inhale didn't make much sense.

tell you what: to ease the burden of choice, I suggest one of the unist be a rEvo and I will happily babysit it and keep it current while you dive another unit

I think he's counting on mine ;-)

 

[MyBuddy]

Revo is a no go unit for me.

I know this is an old thread, but curious what makes the rEvo a no go for you.

 

[rddvet]

I know this is an old thread, but curious what makes the rEvo a no go for you.

A very short answer, too many proprietary parts.

There are several other reasons but right off the bat the amount of proprietary parts rules it out for me.

 

[broncobowsher]

A very short answer, too many proprietary parts.

There are several other reasons but right off the bat the amount of proprietary parts rules it out for me.

I never thought the rEvo had that many proprietary parts. The 1st stages are common and easy to service. The ADV uses standard 2nd stage guts as well. The solenoid is an off the shelf part. The manual add block is simple and uses off the shelf BC inflator parts. The DSV is Drager, nothing special there. The harness and wing can be swapped out with other stuff without hassle. Electronics are from Shearwater, like most other rebreathers. So the housing, scrubbers, lid, and counterlung are bespoke to rEvo. That really isn't that different than any other rebreather on the market.

As any rebreather, they are not perfect. The rEvo counterlung is very easy to maintain between dives, but replacing it is deep surgery. But being deep it is fairly well protected. And the rEvo is a bit tail heavy, especially when diving a wetsuit. I really like the twin scrubbers and the rotation they can do to keep fresh scrubber and not waste sorb. And it does travel nice as a carry on. They all have hits and misses. There are a lot more rebreathers out there that have a lot more propriety in them than the rEvo has. I remember a sales pitch from one rebreather maker that everything is made by them in-house. Which means that any parts you need, they are the only source. At least rEvo you can get parts through Mares parts distribution network. It is pretty easy to get rEvo parts.

 

[mr_v]

@rddvet , @MyBuddy

rEvo's custom parts that may surpise some divers:

- Apeks DS4 regulators
- Lungs
- Backplate

The rest of the unit is as "proprietary" as any other unit.

rEvo is highly modular becuase it does not have a head. The most expensive part, exluding Shearwater stuff, is the battery box which is ~$500. You can quickly replace everything but the lungs. Most parts will be on your front door within 24 hours, as Mares distribution center in FL and customer support in Belgium are exceptionally awesome.

 

[rddvet]

Y’all don’t have to convince me why revo’s are awesome. It won’t happen. There’s a multitude of reasons I have zero interest in a revo. I only simplified my answer because anytime I give all of my reasons it’s 18 pages of fanboy retorts.

 

[broncobowsher]

Y’all don’t have to convince me why revo’s are awesome. It won’t happen. There’s a multitude of reasons I have zero interest in a revo. I only simplified my answer because anytime I give all of my reasons it’s 18 pages of fanboy retorts.

You may have no interest in a rEvo, but if you are going to call them bad, back it up. The rEvo has faults, every rebreather has faults. At this point you are just bashing for the sake of bashing. As you call people fanboys, you are just the opposite.