Which rebreather and why?

A Place for Discussions On All The Various mCCRs, eCCRs, SCRs & Diving Profiles.

Which rebreather and why?

Postby Andy » Thu Mar 01, 2007 1:00 pm

Just curious, for those who have already bought a rebreather or for those (like me) who would like one sometime... which rebreather and why?

It was a post of chickdivers, where she said that the Megladon had about 5 hours scrubber life, that made me start thinking about it again.

So what features of rebreathers would you want, and why?

I'm mostly looking at the Inspriation, the KISS or the Meg - and all seem to have some virtue.
Andy
Serial Poster
 
Posts: 4628
Joined: Thu Feb 01, 2007 1:29 pm
Location: Auckland

Postby chickdiver » Thu Mar 01, 2007 2:43 pm

There were several reasons behind our choice of the Meg. ("our" pertaining to the group I dive with- 6 of us bought them at the same time).

- it is a very robust machine, yet it breaks down small enough to fit in a rollaboard suitcase, so traveling with it is quite simple.

- the modular design also aids in travel, you can literally use any size cylinders with it.

- it can use virtually any scrubber material, including the ExtendAir cartridge (with an adapter)

- it can be fitted with a radial scrubber for extended scrubber duration.

- it is field serviceable

- one of our group has been diving one for a number of years, and his experience with service and repair has been quite good.

Personally, the only other unit currently on the market that I would be interested in would be the Classic Kiss.
User avatar
chickdiver
Member
 
Posts: 72
Joined: Wed Feb 28, 2007 9:51 am
Location: Pensacola, FL USA

Postby Andy » Thu Mar 01, 2007 3:07 pm

What's the cost of a megalodon in the US? About $9k? I would guess somewhat cheaper than an Inspiration anyway.

Am I right in thinking that the big difference between the Meg and the KISS is that the Meg is a solenoid operated unit, with a ppO2 set point. Whereas the KISS is more like an SCR, in that it has a trickle feed of gas that is below the rate of use - and the adding of O2 is done manually?
Andy
Serial Poster
 
Posts: 4628
Joined: Thu Feb 01, 2007 1:29 pm
Location: Auckland

Postby chickdiver » Thu Mar 01, 2007 3:18 pm

Andy wrote:What's the cost of a megalodon in the US? About $9k? I would guess somewhat cheaper than an Inspiration anyway.

Am I right in thinking that the big difference between the Meg and the KISS is that the Meg is a solenoid operated unit, with a ppO2 set point. Whereas the KISS is more like an SCR, in that it has a trickle feed of gas that is below the rate of use - and the adding of O2 is done manually?


The "stripped" Meg (no backplate, first stages or cylinders) ran about $8500 USD in Dec. '05. I think they may have changed the pricing since then.

Yes, the biggest difference int he Meg and the CK is the the Meg is an ECCR- it has an electronic controller. The user sets the PO2 setpoint, and then the computer will cause the solenoid to fire periodically injecting O2 into the unit to maintain the desired setpoint. It can also be used manually, with the user controlling the setpoint via the manual O2 add valve, and using the computer controller as a "backup" (this is how I run mine). The CK is an MCCR, and has an orifice valve which is designed to maintain a minimal setpoint (enough to maintain consciousness), and the user manually adds O2 to maintain the desired dive setpoint. Interestingly enough, there is a new version of the Meg on the market, known as the COPIS Meg. The COPIS Meg works just like the CK.
User avatar
chickdiver
Member
 
Posts: 72
Joined: Wed Feb 28, 2007 9:51 am
Location: Pensacola, FL USA

Postby Andy » Thu Mar 01, 2007 7:47 pm

So the Meg is basically half way between the KISS and the Inspiration? Not fully manual, but not having the fancy fancy electronics/own deco model etc?

With the way you run your Meg, is it a different "mode"? Or is it simply that if you control the ppO2 manually then the solenoid should never have to do anything?
Andy
Serial Poster
 
Posts: 4628
Joined: Thu Feb 01, 2007 1:29 pm
Location: Auckland

Postby chickdiver » Fri Mar 02, 2007 1:59 am

That's a pretty good description. The Meg's next version of software (Apecs 3.0) will incorporate real time decompression info. I doubt I will upgrade, however. GIven the plethora of decompression algo\rythms on the market, the fact that manufacturers routinely "pad" algorythms to reduce liability, and my own personal experience with various algorythms- I prefer having the option of running whatever I please (in my case it's VPlanner).

That is exactly how I run my Meg. I set a setpoint, and run the unit manually, so that should I get distracted or have to deal with soemthing else, the solenoid will fire as a "failsafe".
User avatar
chickdiver
Member
 
Posts: 72
Joined: Wed Feb 28, 2007 9:51 am
Location: Pensacola, FL USA

Postby Azza » Fri Mar 02, 2007 7:01 am

If Andy buys a breather will he get cookies? :D
Azza
Member
 
Posts: 1911
Joined: Mon Dec 18, 2006 3:39 pm
Location: Auckland

Postby chickdiver » Fri Mar 02, 2007 8:12 am

LOL, if I drag any of you guys to "the dark side" I will happily bake the cookies (hopefully they will still be edible by the time they make it over there)!
User avatar
chickdiver
Member
 
Posts: 72
Joined: Wed Feb 28, 2007 9:51 am
Location: Pensacola, FL USA

Postby Azza » Fri Mar 02, 2007 9:40 am

Hear that Andy....No Excuses now!

I would actually be interested in coming to the Dark Side, especially given He prices here...I dont think KtL would let me spend that much money to buy more diving kit tho...
Azza
Member
 
Posts: 1911
Joined: Mon Dec 18, 2006 3:39 pm
Location: Auckland

Postby Andy » Fri Mar 02, 2007 9:46 am

Azza wrote:Hear that Andy....No Excuses now!


Other than the complete lack of cash.... :(

I'll just talk about it, plan which one to buy.... and then change my mind at the last minute because something new has come on the market.

See, I made that mistake last night - I looked at the specs of the Optima!

I'd definitely tend towards a solenoid based unit, I think.


Presumably with using Vplanner, CD, your redundancy comes in with multiple profiles - e.g. one assuming that your ppO2 set point is stuck to through the dive, with a higher set point for deco. Then your back up would be a deco schedule assuming that you have to switch to OC bailout?
Andy
Serial Poster
 
Posts: 4628
Joined: Thu Feb 01, 2007 1:29 pm
Location: Auckland

Postby chickdiver » Fri Mar 02, 2007 10:15 am

Andy wrote:

Presumably with using Vplanner, CD, your redundancy comes in with multiple profiles - e.g. one assuming that your ppO2 set point is stuck to through the dive, with a higher set point for deco. Then your back up would be a deco schedule assuming that you have to switch to OC bailout?


Correct. Also bear in mind that once I am in the deco phase of the dive I can bump the setpoint up appropriately. For example, I run a stepoint of 1.0 - 1.2 for the dive, and then bump up to 1.4-1.6 for deco. The tables are actually the same. The idea that a constant setpoint buys you a whole bunch of time off deco is really a myth unless you are talking about extremely long dives. Running the profile with a constant PPO2 vs. OC buys you typically >5 minutes. Since I have tables run for lots of depth ranges that I have tweaked over the years and am happy with- I dive them rather than running new ones.

I trained with a guy on an Optima. I wasn't impressed with it. The electronics eat batteries (the guy was advised to take them out of the handsets at night) and the ExtendAir cartridges are expensive and bulky. Once you open one, it is dead whether you use it or not. The unit itself is also bulky and it puts significant weight in the lower back, which throws your trim all to hell.
User avatar
chickdiver
Member
 
Posts: 72
Joined: Wed Feb 28, 2007 9:51 am
Location: Pensacola, FL USA

Postby Andy » Fri Mar 02, 2007 11:47 am

chickdiver wrote:The idea that a constant setpoint buys you a whole bunch of time off deco is really a myth unless you are talking about extremely long dives. Running the profile with a constant PPO2 vs. OC buys you typically >5 minutes.


Sorry, you're going to have to run this one past me again....

What I think you're saying is that if you dived a perfectly square profile, where on OC you've got the same bottom ppO2 as on the breather - then you you've essentially got the same actual deco time on the two, give or take a few minutes.

The difference, I guess, comes in that if you're multilevelling the dive (like I can afford a VR3 right now...!), that the fO2 is increased to keep the ppO2 on the breather constant as you come shallower then it's making a huge difference on your NDL as the ppO2 is always 1.2-1.4, whereas on OC it's dropping as you ascend.

I trained with a guy on an Optima. I wasn't impressed with it. The electronics eat batteries (the guy was advised to take them out of the handsets at night) <snip>


Well, that's enough for me... thanks for that. Scratch that one off the list.
Andy
Serial Poster
 
Posts: 4628
Joined: Thu Feb 01, 2007 1:29 pm
Location: Auckland

Postby Smiler » Fri Mar 02, 2007 1:53 pm

Not sure if you guys have access to poseidon kit at a reasonable price but this may be of intrest to you.

http://www.poseidon.se/index.asp?LangID=4

the SIS Lunar has been re-invented and will be on the market very soon at a nice price
User avatar
Smiler
Member
 
Posts: 21
Joined: Wed Feb 28, 2007 3:01 pm
Location: Milton Keynes, UK

Postby Smiler » Fri Mar 02, 2007 1:56 pm

sorry that should be CIS LUNAR and follow the link to the mk5
User avatar
Smiler
Member
 
Posts: 21
Joined: Wed Feb 28, 2007 3:01 pm
Location: Milton Keynes, UK

Postby DiveDiva » Fri Mar 02, 2007 3:06 pm

Do you have a rebreather Smiler?

DD
DiveDiva
Forum Administrator
User avatar
DiveDiva
Forum Administrator
 
Posts: 3062
Joined: Sat Nov 11, 2006 4:23 pm
Location: Pommieland

Next

Return to Rebreather Diving

Who is online

Users browsing this forum: No registered users and 1 guest