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Thinking of a rebreather

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For some reason, the units that come to mind are the Evolution, rEVO and KISS. I know that Ryan moved from the KISS to the rEVO, and I'm dying to know why. It could influence my decision a great deal!

 

The Evolution is a great rebreather, but it is sometimes difficult to get hold of the small tanks in remote locations. You can fix this by buying a travelframe from Decoweenie, then you can mount any size tank. The profile in the water is also a bit bigger because of the OTS (over the shoulder) lungs. And if the electronics go, you could miss a dive or even a trip. The latter never happened so far. If you are interested in deep diving; the Evo is certified to 150 meters.

 

With the rEvo you have BMCL (back mounted counter lungs). This keeps your chest free and reduces the profile. The rEvo has probably one of the smallest profiles due to the dual scrubber setup. If the electronics go, you just use it as an mCCR. It has been taken down to 150 meters recently on a wreck dive in Egypt but I'm not sure what depth the rEvo is certified for.

 

I have no personal experience about the KISS so I'm not going to comment on that unit.

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With the rEvo you have BMCL (back mounted counter lungs). This keeps your chest free and reduces the profile. The rEvo has probably one of the smallest profiles due to the dual scrubber setup. If the electronics go, you just use it as an mCCR. It has been taken down to 150 meters recently on a wreck dive in Egypt but I'm not sure what depth the rEvo is certified for.

 

hi all,

for the eCCR version we did not yet advise a max depth, but that will probably be linked to what WOB you will allow, and what temperature you will dive:

 

in the near future we will release different WOB options, or kits that can be added to the standard rEvo.

 

with the lowest WOB option, and using the dual radial scrubbers, I suppose 160m is no problem in +10° celcius water.

 

paul

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hi all,

for the eCCR version we did not yet advise a max depth, but that will probably be linked to what WOB you will allow, and what temperature you will dive:

 

in the near future we will release different WOB options, or kits that can be added to the standard rEvo.

 

with the lowest WOB option, and using the dual radial scrubbers, I suppose 160m is no problem in +10° celcius water.

 

paul

 

Hi Paul,

 

thanks for participating in this thread.

I have a question. I find WOB one of the most important aspects on a rebreather because it can and has caused CO2 retention problems. Can you give us an idea how the WOB of the rEvo compares to the WOB on the KISS and the Evolution/Inspiration?

 

Also is there a big benefit from the radial scrubbers compared to the axial scrubbers?

 

Peter

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As Matthew pointed out with eCCR’s and divers that are more prone to be distracted during a dive, relying on a computer flying the system for you may buy you some time should you be momentarily distracted from monitoring your PO2, but it should never be a replacement for the central processor between your ears. To me, running a electronic set point for PO2 is the same as putting your car in cruise control. Just because its on doesn’t mean you shouldn’t be watching both the dash and road while you are driving.

 

It’s that type of complacency - rely too heavily on the electronics that has gotten people killed on eCCR’s. What it boils down to is your training, mindset and above all diligence.

 

Taking it from Tom Mount, master rebreather instructor and former underwater photographer back in the 70’s and early 80’s has this to say about CCR’s "For the diligent diver, closed circuit rebreathers are actually safer than open circuit scuba."

 

Now when it comes to choices between eCCR’s and mCCR’s, I am little bias towards mCCR’s. My own evolution with rebreathers began, like many with the Drager Dolphin SCR back in 2001. In 2003 I wanted to go fully closed so I got trained and certified on the Inspiration Classic. For the next year, and 25 hours (you log your underwater hours like a pilot logs their flight time) later, as wonderful as it was to be totally silent, not to mention having more time to do what ever underwater, the electronics in that system reaffirmed by belief about electronics in the marine environment. As any here knows electrical systems are deathly allergic to saltwater. To say the least I had a few dives aborted, missed or near missed from fussing with the unit during setup to just having something in wiring go south requiring me to either bailout or resort to flying it manual.

 

Eric, I don’t know fully why Ryan switched from the KISS Sport to the Pelagian to a eRVO, but you are welcomed to call me for more info on the various systems.

 

As for the KISS Sport, I will say this. Since picking up one year ago I have been very pleased with it. Not missed a single dive (more than 100 hours on it now) do to something going wrong with the unit, nor have I found it difficult to use. On the contrary, compared the Inspiration it has been a joy for same reasons as cited by Dave Hicks.

 

1. They are easy set up (20 minutes tops), and break down and clean.

 

2. Simple unit, easy to service. ith the exception of the units two regulator first stages, you can pretty strip down and repair/replace anything on it with a small Phillips and standard flat screwdriver, cresitwrench, and needle nose pliers. One leatherman in the toolbox and you’re ¾ there.

 

3. Being predominately mechanical, with the only electronics being three independent PO2 readouts, problems have been almost non-existent so far. Manual CCR’s have the best track record for safety in CCR’s. I particularly love the fact that once it set up, I rarely need to touch or fuss with the unit between dives.

 

4. WOB - I have experience with both backmounted and over the shoulder (OTS) counter lung models to make some comparisons. Yes OTS are somewhat better for WOB, but they also ad clutter to your neck and chest, where as back mount does not. Everything is a compromise.

 

5. For travel, if you don’t need to bring the tanks, the entire unit can be compressed down to fit easily in carrying on.

 

6. Cylinder requirements (for air and O2) - pair of 13’s, 14’s, 17’s or 19’s, steel or aluminum.

 

7. Sorb – The Sport KISS can use just about anything out there from the stuff used in Drager Dolphins to the finer mesh required for the Inspirations and evolutions.

 

8. Onboard electonics – only three, basic PO2 monitors. To dive it in a recreational capacity (10 to 130 feet) and any two gas programmable nitrox computer will do.

 

9. And finally, in addition to the fish being a little more cooperative, you have time. Last summer me Doug Ebersole pulled an 84-minute dive with sandtigers (see photo below) in 90 feet of water with no deco obligations, other than a three minute safety stop, at the end.

 

In addition to myself, Doug Ebersole, and Dave Hicks on this thread. Here are a few more photographer/videographers currently dive KISS rebreathers.

Alan Studly

Mar Shargel – who just published the California book Wonders of the Sea.

Berkly White – owner of Backscatter.

Norbert Wu – I think most everyone knows who Norb is.

 

If you are still in the tire kicking phase of your decision on going CCR, it really helps to go back those three back issues of the Underwater Journal. Me Doug have put a lot of work into this subject with still more to come.

 

And should you do, welcome to the Dark Side.

post-4290-1215268588_thumb.jpg

Edited by Walt Stearns

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As Matthew pointed out with eCCR’s and divers that are more prone to be distracted during a dive, relying on a computer flying the system for you may buy you some time should you be momentarily distracted from monitoring your PO2, but it should never be a replacement for the central processor between your ears. To me, running a electronic set point for PO2 is the same as putting your car in cruise control. Just because its on doesn’t mean you shouldn’t be watching both the dash and road while you are driving.

 

Walt,

 

Heads up displays (HUDs) make diving an ECCR easier and safer. I wouldn't dive one without. With the HUD wou don't need to have your eyes glued to your handsets all the time like you had to do on your Inspiration Classic. The HUD sits in your vision. And you have also your ears. You can hear the solenoid firing what gives a good indication that your computer is working.

 

At the important waypoints during the dive like jumping in, changing setpoint, reaching the bottom, .. I use my handsets. Most of the time I rely on my ears and the HUD.

 

The big benefit for me as videographer is that I can keep my hands on my camera all the time. I don't have to push a button every X-minutes/seconds. There are shots that are difficult if not impossible to make on an mCCR. As an example ascending and filming at the same time. You need three hands to do that :P.

 

There are some people that dive an eCCR (without leaky valve) but control the setpoint manually. That is something that I really don't understand. If you want an mCCR, buy an mCCR or a hybrid like the rEvo.

 

Take care,

Peter

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Hi Paul,

 

thanks for participating in this thread.

I have a question. I find WOB one of the most important aspects on a rebreather because it can and has caused CO2 retention problems. Can you give us an idea how the WOB of the rEvo compares to the WOB on the KISS and the Evolution/Inspiration?

 

Also is there a big benefit from the radial scrubbers compared to the axial scrubbers?

 

Peter

 

Peter, depending what WOB you want, because you can choose.. (the smaller the unit, small hoses, small mouthpiece (less dragg), using big grain sorb in stead of small grain in warm water etc etc)

 

next week I'm again at ANSTI to test 4 different new low WOB kits, and our new dual radial (yes radial makes a hell of a difference when using small grain sorb)

 

will publish the results then, but it is clear that the rEvo outperforms both (w're aiming below 2 j/liter at CE testing standards...)

 

paul

Edited by paulraymaekers

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Agreed, HUDs (heads up display) make monitoring your PO2 easier and possibly safer, particularly in situations where your hands are full, or as cave divers have pointed out, when the environment has gotten so dark and silty that you can’t read your hand sets. But HUD’s are not exclusive to only eCCR’s. They are also adapted to mCCR’s. Both Shearwater and Subsea Systems provide the hardware to do it to both eRVO’s and KISS.

 

Peter, I am sure you remember all those drills you had to perform during your rebreather training – dil flushes, open circuit bailout, flying your system manually, etc., are there for a reason. That your system’s controlling electronics are not infallible. They can at any time, and they all do – saying this from personal experience, go wrong on you, by either taking a time out (CPU crash) or telling you everything is still all right when its not.

 

KISS rebreathers are not fancy, but they do work with the least amount of problems, and almost ZERO fatalities. eRVO’s, I seen the system, could no find anything that I didn’t like about system. And yes, in addition to manual, it also comes in hybrid version, which many are in the opinion (me included), offers the best of both worlds.

 

As for WOB, as Paul has outlined above, there are a lot of factors that influence breathing resistance on a rebreather. Outside of what can be measured mechanically in gas flow resistance tests, the rest is mostly subjective in nature as delivered by the person(s) actually wearing/testing the unit in the water. There again influencing factors that come into play include how hydrodynamic drag that that person has on them, work load, water temp, to the individual’s physical fitness.

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If the diver can't exercise the disipline to monitor their intruments, then they should not be diving a CCR at all. (And probablly not Scuba either!) One on the KEY safety benefits to mCCR is that you do have to monitor and adjust your mix yourself. It's like I used to treat the Table Saw in shop class. If you don't have a health respect for the blade, it WILL bite you!

Dave. You must have missed the words "momentarily distracted" in my post. Which reminds me that a rebreather diver should also have the ability to pay close attention to detail, from setup to post-dive regardless of mechanical or electronic control . Too many near misses can be directly attributed to lackadaisical adherence to details & procedures.

 

I am surprised no one has talked about the other, and equally important part of my post... the need for third party published verification of safety and performance. Rebreathers in any other field, such as mine rescue, firefighting, etc., must be tested and certified to a minimum standard. Not so in diving... so buyer beware.

 

Here is a clip regarding work of breathing, counterlung design and placement which may be helpful to readers. It was originally posted in the Prism II section of Scubaboard by the Hollis group. It is probably one of the clearest explanations of fairly complex principals.

 

"The new method of counterlung evaluation that Dr. Dan Warkander (US Navy NEDU) presented at the DAN tech conference in Raleigh deals with 3 breathing factors that must be evaluated for closed circuit systems. Resistive effort is one; this is the difficulty of pushing or pulling gas in the breathing loop, the difference between a soda straw and a snorkel. Hydrostatic Loading is another; this is the relative difference between the pressure center of the diver’s lungs and the maximum and minimum pressure differentials when the counterlung is fully inflated and fully emptied. The last is Elastance; this refers to the change in shape of the counterlung as its volume changes during a breath.

 

Each of these 3 elements causes the diver to do work when breathing. You can have a mix of theses 3 kinds of work but at some point the diver will become fatigued just from the work needed to breathe. Lower work of breathing is a design objective.

 

In a normal swimming position the hydrostatic load of back mounted counterlungs produces negative lung loading, and chest mounted counterlungs produces positive lung loading. The hydrostatic load of over the shoulder counterlungs comes very close to reducing lung loading to zero. Less lung loading is less work to breathe.

 

Small diameter air passages have higher resistance to flow, or resistive effort. So do elbows, long tubes, flow direction mushroom valves, and thick scrubber beds. Using a sufficiently large diameter throughout the breathing loop, avoiding bends and elbows, using low durometer mushroom valves, and a radial scrubber all reduce resistive effort. Lower resistive effort is less work to breathe.

 

Elastance is related to hydrostatic load changes during breathing. A large flat counterlung (flat side down) would have lower elastance than a long narrow tube (tube vertical in the water column). Over the shoulder counterlungs seem to be a good shape tradeoff for low elastance. Lower elastance is less work to breathe."

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The debate over the benefits and safety considerations when selecting either mccr or eccr has been ongoing within the forums of Rebreather World and Scubaboard for quite some time now. Within each of the different threads pertaining to this subject, I've read valid points on each side of the discussion, which leads me to the opinion that being able to run your unit either manually or electronically, depending on the particular situation a diver is faced with at any particular point in time, is probably the right solution.

 

Personally, I run my Optima electronically, but there are situations during a dive where I feel as though running my unit manually is beneficial. For example, yesterday, during the decompression hang on the third dive of an all day three dive trip, my handset signaled that my battery power was not as high as I would of liked it to be. Consequently, even though I had plenty of battery power to finish that dive and then some, and I have backup alternatives to deal with a battery failure, were that to have happenned, I opted to instead drop my setpoint well below the point I was flying it at during my decompression, and maintain my PO2 manually, which aided in conserving my battery power and ensured that my battery never got to a point where it might have affected my handset. That's just one example of many, but the bottom line is that it's good to have the option to switch between either mccr or eccr.

 

Therefore, I'd have to side with the eccr side of the debate, because unlike mccr's, eccr's give you the flexibility of switching between mccr or eccr, at any given moment, either before, during or after the diver.

 

Adrian

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Peter, depending what WOB you want, because you can choose.. (the smaller the unit, small hoses, small mouthpiece (less dragg), using big grain sorb in stead of small grain in warm water etc etc)

 

next week I'm again at ANSTI to test 4 different new low WOB kits, and our new dual radial (yes radial makes a hell of a difference when using small grain sorb)

 

will publish the results then, but it is clear that the rEvo outperforms both (w're aiming below 2 j/liter at CE testing standards...)

 

paul

 

just as extra info:

 

rEvo rebreathers announces:

 

Because of the excellent cooperation with Shearwater Research Inc, and the belief and confidence in their products, rEvo rebreathers will start supplying their rebreathers with a wide range of Shearwater electronics.

 

Besides the current mCCR rEvo with dual rEvodream and HUD's (package 1), the newly available electronic packages on the basic rEvo rebreather will be:

 

Package 2: hardwired triple PPO2 display with depth/time function combined with one rEvodream/HUD

(can be upgraded to package 4 and package 6)

 

Package 3: triple PPO2 display with depth/time function with fisher connector combined with one rEvodream/HUD

(can be upgraded to package 5, but not to set-point controller)

 

Package 4: hardwired full trimix OC/CC computer with real-time PPO2 tracking combined with one rEvodream/HUD

(can be upgraded to package 6)

 

Package 5: full trimix OC/CC computer with real-time PPO2 tracking with fisher connector combined with one rEvodream/HUD

(no upgrade to set-point controller possible)

 

Package 6: set-point controller for complete e/hCCR function, with full trimix OC/CC computer with real-time PPO2 tracking combined with one rEvodream/HUD

 

To each package an extra rEvodream/HUD can be added, for triple electronic redundancy.

 

rEvo rebreathers believes that this new range of electronic packages allows the user to compose their rebreather the way he prefers, at the least cost.

 

Paul Raymaekers

 

ps: more about new WOB upgrades will follow end of the week

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Great discussion and some very useful info, thanks all!

 

I have a few more questions, which hopefully will help others in the same boat as we me:

 

1/ Walt, you wrote:

" To dive it in a recreational capacity (10 to 130 feet) and any two gas programmable nitrox computer will do. "

 

Does this mean that the KISS provides a fixed fO2, as opposed to a fixed PPO2?

 

2/ Matthew, you wrote:

"Each of these 3 elements causes the diver to do work when breathing..<snip>.. but at some point the diver will become fatigued just from the work needed to breathe. Lower work of breathing is a design objective."

 

Now, is CO2 buildup due to WOB a real issue with most rebreathers, or a theoretical risk to be avoided?

 

3/ Peter, you wrote:

"There are shots that are difficult if not impossible to make on an mCCR. As an example ascending and filming at the same time. You need three hands to do that"

 

Ok, now I am a little confused. I was under the impression that even with mCCRs using fixed mass systems, you didn't have to actually adjust the dliuent/O2 every time you changed depth.. only if there was a significant change in breathing rate. I can often see myself moving up and down a significant bit (eg, when trying to photograph barracudas in mid-water) while taking photos. If I need to be fiddling with the O2 mix every time I go up and down, then yeah, perhaps eCCRs may be the way to go.

 

4/ Paul, we've been on email discussing the rEVO as well. I've sent you a separate email with a few questions as well.

 

Walt, I am on the islands on a hamster-powered internet. Downloading a 6MB file is about as likely as Angeline Jolie coming to give me a full body (her's) massage. I'll be downloading those issues when I have access to a faster connection starting a week or so from today.

 

I am indeed converting to the Dark Side - plan is Nov to the Red Sea to get certed. The only question is, what sort of scubasaber will I carry :lol:

 

Cheers,

Vandit

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Now, is CO2 buildup due to WOB a real issue with most rebreathers, or a theoretical risk to be avoided?

 

A high WOB WILL cause CO2 retention. This is a real danger, not a theorethical one. Combine any rebreather with excercise, like swimming with a camera against a current and you risk CO2 retention. Any rebreather breathes more difficult than a normal regulator.

 

I had two issues with CO2 retention. The first one caused me to bailout at 50 meters with a good half hour of deco. That one was no fun at all. And my RMV was through the roof for a couple of minutes. The second one happened a year ago when finning against the current at 60 meters with a large video housing. I managed to stay on the loop that time, but it came close. So I take CO2 retention very seriously.

 

3/ Peter, you wrote:

"There are shots that are difficult if not impossible to make on an mCCR. As an example ascending and filming at the same time. You need three hands to do that"

 

Ok, now I am a little confused. I was under the impression that even with mCCRs using fixed mass systems, you didn't have to actually adjust the dliuent/O2 every time you changed depth.. only if there was a significant change in breathing rate. I can often see myself moving up and down a significant bit (eg, when trying to photograph barracudas in mid-water) while taking photos. If I need to be fiddling with the O2 mix every time I go up and down, then yeah, perhaps eCCRs may be the way to go.

 

An MCCR injects O2 slightly below you O2 metabolism rate. So if you stay a the same depth you have to press the manual o2 injection button every x minutes. If you rise in the water column the volume of the counter lungs will expand. This cuases a PPO2 drop, so you will have to add O2 manually to compensate. You will also have to vent the extra volume to keep the loop at minimal loop volume, but that can easily be done via the nose or by loosening the grip of your lips on the mouth piece.

There used to be a valve for the KISS that allowed the diver to add O2 with his tong, but that is not available any more.

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2/ Matthew, you wrote:

"Each of these 3 elements causes the diver to do work when breathing..<snip>.. but at some point the diver will become fatigued just from the work needed to breathe. Lower work of breathing is a design objective."

 

Now, is CO2 buildup due to WOB a real issue with most rebreathers, or a theoretical risk to be avoided?

 

 

Cheers,

Vandit

Hello Vandit.

 

Co2 buildup/ breakthrough is one of the most critical issues in rebreather diving today. It can and does affect all rebreathers, regardless of design. There are ways to minimize the potential for critical buildup, which should be covered in any RB class.

There is no direct measurement of CO2 concentrations being done in any "sport" rebreather on the market today and this ability to measure CO2 in the breathing loop could be considered the holy grail of safe rebreather design (along with accurate gas delivery and control). Several ideas are floating out there of how to do such measurements accurately, and some industrial applications already do such measurements. Now we just have to find a way to make these measurements in the humid environment of the breathing loop in a consistent, cost effective way that does not require complex maintenance to assure accuracy.

There are thermistors (temp sensors) on the market which can to some degree measure CO2 scrubbing activity but I have not yet seen any peer reviewed, credible source white papers which show with certainty that they are an accurate gauge. They must not be confused with measuring CO2 concentrations inside the loop at any given point in time. They do not.

Work of breathing has direct and indirect effects on CO2 buildup and can be minimized through rigorous design and testing.

Again, independent testing is the #1 benchmark I would use at this time when deciding on which rebreather to purchase. One of the most deplorable issues in this market today is that known, critical design flaws which come to light are not immediately broadcast to the RB manufacturers customer base, and several designs presently on the market have known, critical design flaws yet are still being marketed as is.

Remember, they are simply tools, not an extension of your ego, so don't get caught up in the "mine is better than yours" debates. Choose the tool which has independent laboratory testing behind it and a company which is responsive to, and protects their customer base.

Design flaws can and do happen in any industry but not alerting your customers when they become known is inexcusable.

Automotive hard & soft recalls come to mind here.

Edited by MatthewAddison

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I have dived many different rebreathers - all while using a camera - and whilst the WOB on paper may be vastly different, I have never found it to be an issue underwater.

 

The best solution to CO2 build-up is to start any high work or deep dive on a clean scrubber, and to get out of the habit (that all us photographers have) of holding our breath while taking a picture.

 

eCCR are fine on deep dives, but can be a hassle when working on fine positioning for macro pics on shallow dives. A slight rise can lead to a runaway O2 injection and runaway buoyancy. If you have to resort to flying an eCCR manually in such situations, mCCR is a much smoother solution. Inspiration/Evolution rebreathers are particularly aggressive on O2 injection for this type of work.

 

My latest toy is a rEvo with the hybrid mCCR/eCCR and I confess it is the nicest rebreather I have ever dived and extremely well engineered. I can shift between manual and electronic control as suits the job. My only caution is that whilst it is very light out of the water, it is also very negative in the water. Fine with a thick wetsuit or drysuit, but it could be an issue if I tried to dive it wearing anything less than 5mm of neoprene. My second choice would be a Megalodon, which I understand is now also available in hybrid mCCR/eCCR form.

 

Get an integrated dive computer and maintaining a stable PO2 for those ascending chase shots is not an issue, just let it wander and let the computer work out the deco, though as a diver you still have to make sure the PO2 does not drop below danger levels. An eCCR in such situations can again lead to runaway O2 injection while chasing the set point.

 

John

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My latest toy is a rEvo with the hybrid mCCR/eCCR and I confess it is the nicest rebreather I have ever dived and extremely well engineered. I can shift between manual and electronic control as suits the job. My only caution is that whilst it is very light out of the water, it is also very negative in the water.

 

John,

how is your trim with the rEvo. Do you need extra weights at the top?

Peter

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John,

how is your trim with the rEvo. Do you need extra weights at the top?

Peter

 

I like to be a bit top heavy - a photographer’s habit to get my nose closer to the critters. 6 to 8 lb attached to the grid at the top works about right for me. Those using a rEvo who are just diving it seem to go for 4lb or 2kg.

 

John

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I recently switched from an Inspiration rebreather to the rEvo. Finally a small unit that can be handled while I take my camera with me.

 

I took a look at the new Boris Sentinel the other day. It seems a very well engineered piece of kit with bags of redundancy. No one's saying anything bad about them and a lot of them are being trialed at NDAC - one of the UK's deepest inland sites. For me, the choice would probably come down to an Evo Vision or a Sentinel...

I believe the Sentinel is too big and too heavy. I don't see any point in getting a Sentinel and not the rEvo. The Sentinel is new and has not proven to be a stable platform for photographers yet.

 

For some reason, the units that come to mind are the Evolution, rEVO and KISS. I know that Ryan moved from the KISS to the rEVO, and I'm dying to know why. It could influence my decision a great deal!

Get the rEvo. I don't like the over the shoulder lungs of the Evolution or the Inspiration. That was maybe my main issue to switch over.

 

I just installed the Shearwater Pursuit computer on my unit (well Paul dit that). It's connected with three cells, so I have another PPO2 display. I have decided not to move to the fully eCCR package right now because I want to learn how the handle the rEvo manually. The solenoid will be added next year. I will hopefully do my first story in the Red Sea later this year on the rEvo.

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I have moved around a lot, so maybe I'm not the best test case. A bit of a gear head I guess.

 

While I can't believe I'm saying this, I think Sentinel is probably the best rebreather available for keeping an idiot alive. The electronics package is very well designed. It is far too big, heavy, and has too high of a loop volume for my needs.

 

I can't stand over the shoulder counter lungs. Pelagian was the best, as they curve under my arms, bu they are still enough in the way to be a bother. rEvo breathes so well that I don't miss them, and the 2008 rEvos breathe significantly better (on a machine at least) than the one I have.

 

The rEvo is much faster to tear down, clean, and prepare for the next day's diving than anything else I've used. The build quality far exceeds every other mCCR on the market. The huds are a requirement for my diving, and they are integrated extremely well. The integration with the Shearwater Pursuit adds a very solid setpoint controller package which I have purchased, but not installed yet. I've used the Shearwater Pursuit as my deco computer for almost a year, and am extremely impressed with its simplicity and reliability. I wanted a bit more scrubber capacity for big dives than the stock revo has, but that has been solved with the new radial scrubbers as an option. I may only use them once or twice a year, but I am glad to have the safety margin when I do.

 

As is the unit is pretty heavy in the water. I wish I had purchased the titanium case. I have carbon fiber tanks which make the in water weight a lot better, but the rig is very negative with 3l steels. I also wish the rebreather were lighter for travel. Other than that I'm very satisfied.

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As is the unit is pretty heavy in the water. I wish I had purchased the titanium case. I have carbon fiber tanks which make the in water weight a lot better, but the rig is very negative with 3l steels. I also wish the rebreather were lighter for travel. Other than that I'm very satisfied.

 

I own the titanium (mini) version and it's great. Not too heavy at all and suitable for traveling.

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I own the titanium (mini) version and it's great. Not too heavy at all and suitable for traveling.

 

How much does the titanium version weigh (without tanks & sorb, fully loaded)?

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How much does the titanium version weigh (without tanks & sorb, fully loaded)?

 

I thought it's around 17kg with carbon tanks. Is Paul still active in this thread?

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Aloha-

 

Both my husband and I are rebreather certified and own the Sport KISS, have been for about 2.5 years now.

 

As for the machine itself, it works great, is the most simple I have seen to put together, and is designed exactly for recreational diving.

 

We have another point of view on the subject:

 

-the learning curve is very different and it takes awhile to get used to the entire process

-you have to check your PO2 every minute so get used to looking away from your subject often

-we find the setup and testing to be cumbersome and each time requires a tweak/fix of some kind. The rebreather doesn't break, it just seems to be the nature of rebreather systems.

-we do not see a HUGE difference when filming animals by not having bubbles (I know people will argue this) but weighed against the setup and cost, I am not convinced it's worth it.

-I personally prefer to focus my money and attention on my camera versus the rebreather

-If you want to travel with it, get ready for setbacks. We went with a group out of the country and the O2 compressor broke so they each only got 1/2 02 fills for the day. In addition, absorbent isn't always available and multiple members of our traveling party have had their bottles confiscated by TSA.

 

 

I just wanted to give you another POV since we are considering selling ours after a huge investment. You have to really really want it and know if will make a big difference for you.

 

One of the guys we met during our cert process told us to go buy a corvette instead, he was on to something.

 

Good Luck!

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Diva

Rebreathers do work but the cost/benefits must be weighed in with the type of shooting. In Vandit's case, he wants to get close to fish in the Andamans. A CCR will allow him to swim into schools of fish without bubbles interfering with the shot (aesthetics) and get a little closer to skittish fish (there is still the whole big hulky diver to consider, so the proximity to subject isn't going to be suddenly in your face close). Obviously the difference wasn't enough for you to justify the costs involved, but a corvette?!? ;)

My own experience with CCR and SCR is that it works amazingly well for certain marine life, especially the bigger ones like sharks and cetaceans. In fact, I'd say for a few projects I've been involved with, the CCR were invaluable and the whole shoot would've failed without them.

That said, they are a pain to travel with. I usually fedex the rebreather ahead. The ever inconsistent TSA is unfortunately solely a US problem. The airlines also set up their own rules so it's best to have something in writing to show TSA. That said, the few times I've seen TSA confiscate tanks is when the passengers try not to declare it and/or pack it with valve inserted.

You are absolutely right in saying that rebreathers are not simple plug and play toys. I would hope anyone contemplating getting into it will understand the technical and rigorous maintenance it requires.

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Vinnie,

 

Hi there, hope all is well out in the Andamans

 

At the moment the consensus at non expedition level, for all round performance, reliability, and sustainability would appear to be the Sentinel (albeit that it is a new kid on the block), especially when the travel/OSCL version becomes available probably early in the 1st quarter 2009. The rEvo (at least in Europe) is also gathering a considerable following but they are quite different units.

 

There appear to be few (very few), professional instructors or experienced RB divers of its closest competition, that cannot compliment its superior performance range and reliability overall.

 

The quality of support from CCRB Ltd is already legendary, and the lineage of the Ouroboros as a foremost expedition RB in the recreational market speaks for itself.

 

If you are going to have to suffer the normal distractions of underwater photography, the Sentinel probably provides some of the best electrical support to enable you to do this with the quality of the HUD and the computer function.

 

I think I've lost your email, if you can email me I've got a lot of stuff on the Sentinel (but there's also a whole load on the CCRB and other Websites) I'll send you

 

The "high" capital cost of rebreathers is an alien concept to most OC divers, and of course 99.9% of divers come from OC, but it begins to show comparable economic sense when you actually evaluate the real costs at most scales and scopes of mixed gas OC technical diving operations.

 

Gas production cost, availablility, transportability, with related containment costs, plant and machinery etc are all costs/facilities that need to be satisfied one way or the other. I think you know more than most that the compressed gas part of the equation can become the most involved.

 

I think someone needs to work up a good graphical cost comparison model

"cost-v-function/capital-v-expendable/small maintenance-v-large maintenance/portability-v-destination sustainability"

 

As a technical diver (with cameras) yourself, you know that some of the above costs can invert when you think of air travel - an oc diver won't take bottles, just his regs, a RB diver has to look at baggage weight allowances seriously even with some of the bare bones RB travel rigs, and of course doesn't want to carry the extra weight of sofnalime weight if they can get it at destination.

 

I think recreational diving has actually been operating at a technical level far longer than we realise in terms of simplistic decompression diving before the advent of PADI etc. However we all know that mixed gas has become more and more available in OC, and that CCRB diving has become incredibly more sophisticated as computer and sensory electronics have advanced. Neither market has really matured yet but doubtless the eCCR market will now ride and climb the fast moving IT wave.

 

 

There is definitely an emerging demand for try diving rebreathers both in the UK and in the Red Sea. Many organisations are rising to this challenge in order to close on purchasers doubts and worries. Nearly all the prominent UK RB outlets offer these, as in the Red Sea do Tekstreme(Emperor) Sharm and Hurghada, and Orca need a mention as well. (There are others!)

 

 

I'm sure all of this is deliberately sent to try us, and make us value it or hate it, all the more!

 

 

 

Best Regards

 

 

 

Gordon Theo & Ben

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