Halcyon Rebreather

[markosis]

How do rebreather people.

I'm interested in finding out a bit more about various Be reavers and I wanted to start with the one I understand the least about.

I'm thinking about moving to a rebreather sometime over the next three - four years as I believe its the way forward for me for the diving that I'm beginning to do more of.

Now, I've had a good gander at the Halcyon site and I've got a few questions about the RB80.

1. How does it work. It seems like a cross between an SCR and a CCR. Does it have any electronics and how do the alarms work. I know some of them work by changing the breathing cycle so you notice fairly obviously.

2. Has anyone here used one?

3. How would you go about getting training, would you do it via GUE or would independent centres run modular courses on it like all the other units

4. Any idea on cost?

5. Is it safer than Electronic CCR (one of the problems I have with CCR is the electronics issue) and is the ppO2 monitered by cells or does it stay constant. Is the system more a way to eke out your chosen back gas rather than give all the benefits of a full CCR?

6. Being made by Halcyon, how likely is it to fall apart underwater?

I hope that someone has some answers as I'm really quite interested in the system.

(Edited because I can't proof read)

[Janos]

Originally Posted by markosis

How do rebreather people.

I'm interested in finding out a bit more about various Be reavers and I wanted to start with the one I understand the least about.

I'm thinking about moving to a rebreather sometime over the next three - four years as I believe its the way forward for me for the diving that I'm beginning to do more of.

Now, I've had a good gander at the Halcyon site and I've got a few questions about the RB80.

1. How does it work. It seems like a cross between an SCR and a CCR. Does it have any electronics and how do the alarms work. I know some of them work by changing the breathing cycle so you notice fairly obviously.

It is an SCR. It dumps about 10% of the counterlungs each breath.

Originally Posted by markosis

2. Has anyone here used one?

You need to be GUE trained to buy an RB80. The EDO-4 is a clone, which is meant to be very similar (although DIR people say there are significant differences)

Originally Posted by markosis

3. How would you go about getting training, would you do it via GUE or would independent centres run modular courses on it like all the other units

I think you need to be GUE Tech 2 to take the GUE RB80 course.

Originally Posted by markosis

4. Any idea on cost?

10k?

Originally Posted by markosis

5. Is it safer than Electronic CCR (one of the problems I have with CCR is the electronics issue) and is the ppO2 monitered by cells or does it stay constant. Is the system more a way to eke out your chosen back gas rather than give all the benefits of a full CCR?

I don't think it is safer. It is designed for long penetrations at constant depth and so there are no cells. Think of it as being a way to get 10 times as many breaths from one cylinder.

Originally Posted by markosis

6. Being made by Halcyon, how likely is it to fall apart underwater?

Well there have been no fatalities on the RB80 (but sadly a few on the ED04).

I'm not sure that the RB80 is ideally suited for Ocean Diving. However others will disagree. I think Richard Lundgren on the boards dives one. Also have a read of RebreatherWorld, and "Mastering Rebreathers" by Bozniak, which, although a little dated, explains how one works.

Janos

[Finless]

I didn't even know Halcyon did/sold a rebreather ....... I thought DIR philosophy was against RBs??

Oh well!

[markw]

I've not used (or even seen) a RB80, but my understanding is that it is a mechanically operated SCR, with no electronics or alarm.

Being a SCR, your MOD is based on the choice of gas that you are using with the unit, so I think there are no monitoring options as standard.

Being a SCR also, it's "more a way to eke out your chosen back gas rather than give all the benefits of a full CCR"

I think training is only via GUE, and that you would need Tech2 as a pre-requisite.

There is another rebreather orientated website which would probably answer all your questions on the RB80. I'm not sure if it's acceptable practice to link to potentially competing websites, so I'll pm you with the URL of the other site.

[Freeflow]

1] the Halcyon is keyed to the O2 you use rather than a continual flow rate. It's a bit complex and I'm not sure I fully understand the ins and outs of it myself, I think Sean69 is still active on here he has a clone the EDO-4 that works on the same principle

3] I think you have to be fairly well up the ladder of GUE/DIR courses before you are allowed to use one.

5] As well as eCCR you have mCCR units such as the KISS. SCR electronics are passive and do not control the addition of O2 to the unit.

6] I don't think Halcyon stuff does fall apart under water.

The RB80 is a BIG unit, pretty much anything else is smaller.

Rather than decide on a unit and then the type of diving you want to do with it, you need to see where your diving is going and then get the type of rebreather to match. Although I dive trimix I do it OC and have a Dolphin that I use for most of my other diving. If you have any questions about the Dolphin PM me.

[Freeflow]

Have a look on RebreatherWorld.com too!

[markosis]

Thanks guys.

That answers most of the questions.

Shame you need GUE certs for it as that's not something I'm particularly interested in doing.

[wreckweasel]

Its a nested bellows design, theres plenty of info on these on the net. Try browsing;

www.ron-ger.de/

www.stde.ch/

EDO-04 RMV Keyed Semi-Closed Rebreather - Rebreather World Forums

Essentially its a gas extender, usually in 8:1 but sometimes 10:1 ratio. It'll extend whatever gas you plug into it. There are many clones, some claimed to be worse some better than the RB80 (try the links above).

There are NO electronics so all your alarms are OC intuitive (ie if you cant hear bubbles, its not venting so the loop isnt being replenished.. bail out).

The big criticisms of these units are;

1. Poor choice for ocean diving, they're designed to work best for long depth stable dives.
2. Poor WOB in any orientation other than slightly ass up.

Like any breather, its a tool...... but unlikely to suit diving for a UK ocean diver. A bit like bringing a banana to a knife fight (always a bad idea, unless the banana is to bribe king kong into squashing your opponents).

[W Wilberforce]

Hello Mark,
not surpised you have been considering it.
I have been having exactly the same thoughts in my spare time!

It seems that, from what I have seen and read (never actually used one) that an Ambient Pressure unit (Inspiration) is the way forward.
The Halcyon unit gives out bubbles, just fewer (it is a mostly mechanical unit, not software-controlled) and makes a bit of a breathing noise. Also the gas mix control isn't very sophisticated as it adds oxygen/ diluent at a set rate instead of monitoring the pO2 (ie mechanical not computer-controlled).
If it's cheaper then that's allways good.
The Ouroboros is extremely good but extremely expensive (£10,000 acccording to diver)
The KISS is a good one but comes all the way from the States, as do the parts, and is doesn't have a CE rating and all that entails.

I like the Inspiration because it is made and serviced in Cornwall, every single part is replaceable and better models (Inspiration Vision) have onboard decompression modelling up to 100metres in depth (CE rating apples to 100m also). Also I think (probably) the gas control software (ie best mix) is very sophisticated and can be run manually ( i heard the instructor say this sometime)
Also there are a few second hand models around
This sounds a bit biased but I would go for a CCR rather than an SCR, as you get better mix control (ie setpoint control so longer bottom times etc ) and montoring software.
also GUE training is apparently hard and somewhat arbitrary in procedures.

And yes, it is odd that I am spouting all this when I have never even used tried a rebreather !

Christ i'm a nerd !


Accept this information at your own peril
Will

[Clare Gledhill]

Originally Posted by spunkmire

also GUE training is apparently hard and somewhat arbitrary in procedures.

An interesting throw away line - care to elaborate?

In what way arbitary?