Comprehensive Rebreather comparisons?

schwerve

Hey all,

I'm not an Rebreather diver yet. I'm thinking more and more about it, as the market starts offering decent RB's that I may actually be able to afford within the next decade. I'd love to see an article here on Rebreather World - or, several articles - that lay out the pros and cons of many Rebreather's in wide use, and then rate on the following:

1) Most Value for Money. Yes, you can get a Sport KISS for US $4800. Does that translate into a reasonable "dollar per feature value" compared to an Inspiration, or a Meg, or a Boris?

2) Most User-Serviceable. I'm not big on taking stuff apart, especially when my life depends on putting it back together correctly. I'll swallow my reluctance if I get an Rebreather; still, not everyone is an engineer. An RB is this complex thing with all these parts and I-don't-know-how-to-fix-it! and The-LDS-doesn't-service-it! and What-do-I-do?!? While education goes a long way toward alleviating such concerns, it'd be great to have the article say that Rebreather x is childishly simple to tear down and rebuild, Rebreather's y and z aren't so bad either, but don't even think about an Acme Rebreather.

3) Most Off-the-Shelf (can't think of a better term). Whether you're in Indianapolis (where I live) or in Indonesia, will you be able to run by the LDS for parts - or, hell, Wal-Mart - if your Rebreather craps out? Yes, yes, you'll have a spares kit, but what if you wish to replenish the spares you had to use to fix your RB? Will you need to spend $500 and wait three weeks while proprietary parts ship from the manufacturer?

4) Most Travel-Friendly. As you may know or guess, central Indiana isn't exactly a hotbed of diving activity. Local diving consists of cold quarries with 30ft vis on a good day. The closest interesting diving is four hours away, and it's still farking cold. So, I supplement my two-local-dive-a-month diet with trips to the tropics. If an Rebreather will cause me to pay for overweight baggage all the time, I ain't buying it. Neither will other people in similar situations.

5) Most Friendly to Casual* Divers (speaking of two dives a month). Well, maybe an Rebreather isn't terribly cost-effective for a casual diver such as myself. Price isn't a factor for most divers anyway; diving is definitely not a poor man's sport. Besides, we want warm gas, dangit! Casual divers don't need mixed gas, nor do we need a 600ft rating. Maybe we'll go deco, but it's doubtful.

6) Most User-Friendly. Since I'd like to fiddle with my gear as little as possible during a dive, I wouldn't mind electronics. Or would I? Help me decide.

7) Most Friendly to OC Buddies. My buddy isn't a big fan of Rebreather's at all; the DIR Kool-Aid seems to have gone to his head. Other divers out there have the same problem; they'd like to switch to an Rebreather, but their buddies don't. If you've gone unconscious, can your OC buddy rescue you with a minimum of gauge-reading or futzing with your gear?

8) "Least" in Failure Modes. Most Rebreather's share the same general oh-no factors - hypoxia, hyperoxia, hypercapnia, water in the loop, etc. - but the causes can vary from RB to RB. Is there armor in the breathing hoses? Do the counterlungs have sufficient protection from punctures? Which side is the oxygen injected on, and what implications does that have? Will a solenoid fail open or closed?

Finally, the category I care the most about at this stage:

9) Most Beginner-Friendly. Think of what you would've loved to see in your first Rebreather, then tell us what RB currently on the market comes closest to that ideal.

I'm sure you all can think of other categories to add. Fire away!

* The word "casual" has become a loaded term in some circles. I use it as shorthand for "divers who don't dive all that much, but are smart enough to keep their skills up for when they have a serious stretch of diving, and it hasn't been three years since their last use of SCUBA gear in any setting, they're wearing 50lbs of lead with nothing but a swimsuit, and after their first giant stride off the boat they thunk into the bottom at full speed."

caveseeker7

Welcome to Rebreather World.
That's quite a load in your intro post.

Knowledge falls into two categories, theoretical and practical. There aren't many people who have both on all units, have no personal agenda or vested intrest, have the skill to write well and make the effort to do so. Which makes an article like that hard to come by.

I suggest a fund to get me trained on all units to get some practical experience, I write pretty decently and enjoy it, and I promise to stay as objective as I can.

That depends mostly on what you need and what you want from your rebreather. Obviously for most people the price does play some role, but no matter what it is, if the unit suits your diving you got good value for your money, if not you don't. With diver's profiles, needs and wants spanning a very broad range that is almost impossible to get it right for everyone. Different people value different things.

Probably the Jetsam units. Then again, I never serviced one.
Back to experience ... .

Not a bad term. Some rebreathers use a lot more propriatory parts than others, Dräger comes to mind, as does Steam Machines. I can't think of a rebreather that is sold commercially and build only from off-the-shelf parts.

Propriatory spares for rebreathers tend to be expensive, and most companies have had problems at one point or another getting parts fixed or replaced in a timely manner.

Size and weight. Those numbers are fairly easy to come by.
Also, plenty of info in threads on that subject. The Sport Kiss in the backpack probably takes crown.

That's another tough one, I think. The basic loop tends to be quite simple, and most if not all rebreathers come with check lists for pre- and post dive procedures. The Dive Rite with the scrubber cartridge stands out in that handling it is much easier and more convinient than packing granules. Units that have springloaded compression usually pack easier than units that don't.

Electronics are worth consideration, too. But again, the perception differs from diver to diver. I like them simple (like the PRISM and MK series), without having to scroll through menue after menue to select or unselect a function. Reading through manuals will give you an idea of what to expect and how much fiddling you will have to do. Some units have considerably more options, buttons and menues and hence a higher learning curve (Optima or Boris, for example) and require more practice to be proficient.

Much of the last answer should apply well to this question, too.
I'm not sure if (some) electronics don't translate into more fiddling than not having any. In addition, you need to be proficient in controlling any unit manually, and controlling an eCCR manually is more fiddling than controlling a mCCR manually. A mCCR also translates into staying proficient since you always control the pO2 that way.

Another thought, can you get additional scrubber containers at an affordable price, so you can pack them at home. What does you typical dive day look like? Will you have to pack onboard a rolling boat to do the last dive of the day. That sort of thing.

None of them are unless you have rebreather friendly buddies.
Some may be a bit worse than others due to unit reputation and buddy prejudice. A FFM with BOV is probably the easiest way for a non-Rebreather diving buddy to help. You don't really want people pushing your buttons that don't know what they're doing. If at all.

Not all that much difference, really. Electronic vs. manual gas addition is a main one, enclosed (rear) counterlungs vs. exposed another. So is number of bits and pieces, the more there are, the more can fail. The more connections, the more possible leaks. Pro and cons to all ... take your breathing hose example: Armored provides protection but doesn't allow (easy) crushing, done to check the one way valves during the dive (and making possible to control gas direction in case of failure).

Pretty much the same as in #5 and #6 answers this one.
If the unit is user friendly, it's easier as a beginner to use it.

Anyway, my 3¢ worth ... now lets start the collection.

__________________
Cheers
Stefan



"Political Correctness is a doctrine, fostered by a delusional, illogical minority,
and rabidly promoted by an unscrupulous mainstream media,
which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.!"

Freef

I think a lot depends on what you are going to use the Rebreather for. If you are looking at deep trimix then you will need CCR, if you are looking at a maximum of 40m then you could consider one of the SCR units. I dive a Dolphin and think it's great. The pO2 meter is passive and does not control any part of the loop. The loop %-age is controlled by the % in the tank and the jet size selected [Don't tell Drager that I do this!].

The Dolphin is more versatile than the Ray, and a lot easier to clean. You have the option to turn it mCCR with a bit of fiddling and some parts from narked@90 or similar.

I prefer SCR as it is more like OC diving with less weight. Set up takes about 20 min including packing the scrubber and tests, with 3-5 min of pre dive checks to be done as well. I have dived an Inspiration and found that it was a 'busier' dive than the Dolphin. I was probably monitoring the handsets more than was required, but it was a new experience.

The Dolph has less parts than the Inspiration, and is cheaper. I don't know how it compares to the Sport Kiss in price though.

My Dolphin diving site is on http://dolphindiaries.mysite.wanadoo-members.co.uk/

HTH

__________________
David.

Currently owner of two differently sized ankles.

schwerve

You'll need a second tester, I believe. A beginner such as myself would no doubt be valuable, in terms of perspective. I'd only need... one million dollars. And a pony.
That doesn't prevent Rodale's or Undercurrent from writing gear reviews, does it?

A wide-ranging review wouldn't be terribly detailed, but then the reader could use it to narrow his scope of research down to a manageable level. I'm just sayin'.