I'm considering my first CCR whether is it BM or CM (choptima). My question is the scrubber size I see the choptima is 2.2kg and some BM units have bigger size. Does size matters? I can imagine it's related to the duration. What else? Tks
Question First CCR question
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gordonscuba
Contributor
Here’s one way of estimating scrubber duration:
gue.com
A freshly packed 2.2kg scrubber is typically more than enough for any single dive, until you are very advanced. At this level , it’s only a question if you consider repetitive dives.
Estimating Your Scrubber Duration
Global Underwater Explorers (GUE) rebreather divers use the Absorbent Canister Endurance (ACE) method for estimating scrubber duration.
gue.com
A freshly packed 2.2kg scrubber is typically more than enough for any single dive, until you are very advanced. At this level , it’s only a question if you consider repetitive dives.
Thank you Gordon.Here’s one way of estimating scrubber duration:
Estimating Your Scrubber Duration
Global Underwater Explorers (GUE) rebreather divers use the Absorbent Canister Endurance (ACE) method for estimating scrubber duration.
A freshly packed 2.2kg scrubber is typically more than enough for any single dive, until you are very advanced. At this level , it’s only a question if you consider repetitive dives.
Your first rebreather will be a long-ish term commitment as you've got to get to know it really well. Lots of practice and get diving with it.
Backmount is more traditional and is easier to carry around as you walk it from the car to the boat/whatever.
Chestmount is smaller but a lump on your front, but tends to be lighter with less scrubber. Diluent can be backmounted or sidemounted.
Do not underestimate the amount of time and practice you need on a rebreather before you're competent and safe. At least 100 hours in the water, preferably a couple of seasons.
Backmount is more traditional and is easier to carry around as you walk it from the car to the boat/whatever.
Chestmount is smaller but a lump on your front, but tends to be lighter with less scrubber. Diluent can be backmounted or sidemounted.
Do not underestimate the amount of time and practice you need on a rebreather before you're competent and safe. At least 100 hours in the water, preferably a couple of seasons.
Sorry, but diving a CM CCR (Triton), I will agree to disagree. I'd say carrying my rebreather is easier than any BM unit, just like a handbag, even on a inflatable boat, cluttered with diving equipment, I can keep it in my lap, without getting angry stares from buddies (try that with an AP Inspiration or a Revo). As far as clutter is concerned, I find dividing equipment between back and chest is must more convenient and comfortable.
Many readers are probably jumping out of their skin while reading this, I know. This just proves that choosing a CCR is a HIGHLY personal matter. I've been diving my Triton for 3 years now, but I've been diving among CCR buddies for more than 10 years. In my experience, a guy diving an Inspiration won't dive a Revo, or any other rig and the reverse is true also. I'd say there're no bad CCR on the market right now, but all have their advantages and drawbacks. One good example, since that world record in Font Estramar, the XCCR is all the rage on French forums, but I'm not sure it's the right choice for everyone. I fear it's rather complicated to operate and a lack of proficiency with your rig is highly hazardous.
My advice to the original poster :
- try several CCR to make your own opinion (that's not because the Triton is the right one for me, than it's for you. There're plenty of things to consider : spare parts availability, sending it abroad or not to have the rig serviced when needed...)
- make a list of what you need or want to do with your CCR
And before buying one, be sure it's the one fit for you, because considering the price (training + CCR), if you're wrong it's an expansive mistake.
I think beginning rebreather divers should be size limited to 5-6# scrubbers until they've been diving ccr's for awhile. I have seen too many people try and push a 9# scrubber to the point of breakthrough because tossing the unused sorb after 4 hours is "a lot of waste," but most people don't mind binning the remnants of a 5-6# scrubber after 3-4 hours of use.
Remember, copper wire was invented by two tech divers fighting over a penny.
Remember, copper wire was invented by two tech divers fighting over a penny.
I had wanted to go to a rebreather for a long time. There's a big 'joining' cost with expensive equipment and lots of training. Obtaining budgetary approval was not simple!
In the meantime I read a lot about different rebreathers, much like you read about which new car to buy. As part of this I made my shortlist based upon no knowledge nor experience, but based upon talking to other rebreather divers about their specific machines. I quickly realised that received wisdom is to get something pretty standard and stick to that for some time to develop the skills necessary to get the most out of the unit.
It's interesting to think about some of those shortlisted machines now with the benefit of 4 full seasons diving a rebreather and over three hundred hours.
The easy choice machine was the JJ. Very popular on the dive boats and very few people have bad things to say about them. They have a great reputation as solid machines that have been pretty much everywhere.
In the UK the AP Inspiration is a very popular rebreather, easily the most common machine on dive boats. I dislike the cluttered front mounted counterlungs, the very plasticy feel to everything -- especially that minging yellow cover. I don't like the idea of using the home-grown electronics -- Shearwater is almost a must have. Then there's the number of people I've seen diving on these units, some have shocking trim and cylinders all over the place. OK, personal biases and possibly exaggerated, but seeing three divers in full seahorse trim trailing a cloud of silt really does nothing. So that didn't make it to the shortlist.
As an aside, a diving buddy friend bought one that was old but apparently serviceable. He's spent so much on fixing an tweaking that unit that he could have easily bought a new one.
I liked the look of the X-CCR/X-box. Very well made and very shiny. These have a large radial scrubber so expensive to run for sodalime and also take an age to pack. Kind of ended up on the "long list".
The wildcard was the Sidewinder. Liked the idea of one of those, but even in my no knowledge, no experience state I realised that it's not a great unit to learn to dive CCR and especially as there's few caves in the UK. Basically a 'standard' backmount rebreather would be best.
The last one, which was pretty consistently on the top of the list, was the Revo. Loads of things I liked about it -- and still do. Specifically I like that there's only two hoses on the loop, the lungs are fully encased in a metal case (my friend's T-pieces wore holes in his Inspo lungs and leaked); that there's two scrubbers meaning that CO2 breakthroughs don't happen and switching the scrubbers means using small amounts of lime (1.3kg/3lbs); the redundant electronics with separate Petrel controller and a completely separate Nerd with two separate cells, 5 cells in total, means it's easier to understand and handle cell failures; the extremely clean chest area especially if using AI transmitters for gas; that you can get your hand into the lungs and wipe them clean; the "hybrid CCR" with a leaky valve constantly injecting oxygen and a solenoid should you fail to monitor your PPO2 correctly.
I went for the Revo in 2020 and it's been a brilliant unit. There's weaknesses, mainly that it isn't tolerant to flooding, so don't flood it! I've progressed through MOD2+ 70m/230ft and done many dives to that depth. Have also achieved full cave on the Revo, again, great unit for diving in overheads. Have made a few modifications to it which I've posted on here before.
With four years of diving a Revo behind me and 300 hours, I'm now looking at other specialist units for the specific use cases of travelling and caves. The new shortlist includes:
In the meantime I read a lot about different rebreathers, much like you read about which new car to buy. As part of this I made my shortlist based upon no knowledge nor experience, but based upon talking to other rebreather divers about their specific machines. I quickly realised that received wisdom is to get something pretty standard and stick to that for some time to develop the skills necessary to get the most out of the unit.
It's interesting to think about some of those shortlisted machines now with the benefit of 4 full seasons diving a rebreather and over three hundred hours.
The easy choice machine was the JJ. Very popular on the dive boats and very few people have bad things to say about them. They have a great reputation as solid machines that have been pretty much everywhere.
In the UK the AP Inspiration is a very popular rebreather, easily the most common machine on dive boats. I dislike the cluttered front mounted counterlungs, the very plasticy feel to everything -- especially that minging yellow cover. I don't like the idea of using the home-grown electronics -- Shearwater is almost a must have. Then there's the number of people I've seen diving on these units, some have shocking trim and cylinders all over the place. OK, personal biases and possibly exaggerated, but seeing three divers in full seahorse trim trailing a cloud of silt really does nothing. So that didn't make it to the shortlist.
As an aside, a diving buddy friend bought one that was old but apparently serviceable. He's spent so much on fixing an tweaking that unit that he could have easily bought a new one.
I liked the look of the X-CCR/X-box. Very well made and very shiny. These have a large radial scrubber so expensive to run for sodalime and also take an age to pack. Kind of ended up on the "long list".
The wildcard was the Sidewinder. Liked the idea of one of those, but even in my no knowledge, no experience state I realised that it's not a great unit to learn to dive CCR and especially as there's few caves in the UK. Basically a 'standard' backmount rebreather would be best.
The last one, which was pretty consistently on the top of the list, was the Revo. Loads of things I liked about it -- and still do. Specifically I like that there's only two hoses on the loop, the lungs are fully encased in a metal case (my friend's T-pieces wore holes in his Inspo lungs and leaked); that there's two scrubbers meaning that CO2 breakthroughs don't happen and switching the scrubbers means using small amounts of lime (1.3kg/3lbs); the redundant electronics with separate Petrel controller and a completely separate Nerd with two separate cells, 5 cells in total, means it's easier to understand and handle cell failures; the extremely clean chest area especially if using AI transmitters for gas; that you can get your hand into the lungs and wipe them clean; the "hybrid CCR" with a leaky valve constantly injecting oxygen and a solenoid should you fail to monitor your PPO2 correctly.
I went for the Revo in 2020 and it's been a brilliant unit. There's weaknesses, mainly that it isn't tolerant to flooding, so don't flood it! I've progressed through MOD2+ 70m/230ft and done many dives to that depth. Have also achieved full cave on the Revo, again, great unit for diving in overheads. Have made a few modifications to it which I've posted on here before.
With four years of diving a Revo behind me and 300 hours, I'm now looking at other specialist units for the specific use cases of travelling and caves. The new shortlist includes:
- Sidewinder 2 which appears to have some great technical innovations. Sidewinders are great in overhead environments with a low profile and they work well in the sea. I like that it's pretty lightweight so it should work well for travelling. Sidewinder v1 will maybe come up at sensible prices.
- The little Triton is a great unit and would be fantastic for travel diving and overheads. I'm sure that if one came up at the right price I'd jump for it!
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