halcyon rb80

[madmole]

Thanks, what do you call shallow and how warm is the water?

This makes a lot of difference on the scrubber duration

Thats a lot of dives to stage all those tanks, hats off to anyone daft enough to go that far in

 

[padiscubapro]

wetlettuce once bubbled...
Hi

I have looked at rebreathers for a while but don't like the fact the short scrubber life. The halcyon has a ten hour life supposedly. Anyone know whether the Halcyon is any good or not?

The problem is I've never seen published test results, no listing of what temperature or what rate of CO2 production..

For example the Inspiration is rated at 3 hours at 1.6lpm co2 at 6degrees c.

Thats 288 liters of CO2, at a more reasonable production rate of 1.0 lpm thats 288 minutes or 4.8 hours and thats still being concervative for many divers..

I use on average 1.0 lpm of oxygen over an entire dive, assuming .9 liters of co2 for every liter of oxygen consumed gives me a margin of about 32 liters of co2 production or around another half hour of duration(over the rated scubbber duration)..

This corresponds well with my personal observations as well as many others I have spoken to.

 

[SLJ]

We use it in water >75 and shallower than 130 ft. Scrubber duration would definitely be shorter for colder water, but not really for deeper as metabolism remains the same for any depth. It only takes two to three dives to stage all of the OC, but time for us isn't really an issue.

SLJ

 

[madmole]

Be careful as depth IS an important issue for scrubber duration. The numbers of CO2 molecules may be the same but its partial pressure is increased

Inspiration tests clearly show a rapid reduction in duration with depth. In fact the Inspiration recomendations are

Sofnolime Rule No 1 - Dive Planning
The Sofnolime must be replaced after 3 hours of use for CO2 produced at a rate of 1.6 lpm
Sofnolime Rule No 2 - For subsequent dives deeper than 20m, the diver must leave the bottom when
the total time breathed from the unit reaches 140
Sofnolime Rule No 3 - For subsequent dives deeper than 50m the diver must leave the bottom when
the total time breathed from the unit reaches 100

 

[padiscubapro]

I agree with Madmole, Depth Does effect scrubber duration.. besides an acceptable PCO2, the increased density of the gas reduces scrubber efficiency.. There are a few studies done by the US navy back in the 50s and 60s that clearly show this.
I also know of several people who had some problems early in a dive at depth (>250 fsw) when they were working hard trying to set the hook on a wreck.. One case in particular, FLushing the loop solved the problem and The ccr diver was able to tie in, his OC buddy used up all his gas planned gas and was into his reserve and had to abort before the job was complete. These same divers have done some severe workload dives in shallow water without trouble.
On one dive the hypercapnia got so bad his buddies HID light seemed to almost go out as he described it.
On an SCR your loop might be a bit more forgiving for this type of episode since you will be dumping lots of gas.. but it will still be effected..

If you are under the impression depth doesn't effect scrubber duration, the training can't be that complete(are there any classes other than GUE for that unit??), especially since test data IS available.. On the inspiration thats was part of tthe CE certification, and it pertains to all designs.. Dpeth doesn't effect Metabolic needs of O2, but definately will effect the PCO2

 

[wetlettuce]

Hi

Following on from the 'breakthrough' point, it seems obvious that the way the scrubber is packed is important. I have seen on divesafe.net the azimuth and upcoming nemesis rebreathers which are being fitted with the Extendair cartridge.

Has anyone tried these and should I believe the hype ?

 

[Fetch]

I'm not implying that what you write on the boards or on your website (http://www.btinternet.com/~madmole/divemole.htm) is libelous or anything, but what is behind your continue assertion that GI has a commercial interest in the failure of the BI (and the success of the RB80) ?

Are you aware of some GI - Halcyon connection that the rest of us aren't?

Just curious, and I apologize for the topic drift, but your statements do seem a bit peculiar.

jeff

madmole once bubbled...

Remember the person who claims 11 hour durations is also the same persom who claims not to breath, never need decompressing etc while diving and has a vested interest in the RB80's sales

 

[madmole]

Halcyon is one of the leading sponsors of the WKPP project. Halcyon sell the RB80 who's main competitor is the Inspiration

check out

http://www.wkpp.org/sponsors.htm

Are you likely to bite the hand that feeds you?

 

[swimndive]

madmole once bubbled...
Halcyon is one of the leading sponsors of the WKPP project. Halcyon sell the RB80 who's main competitor is the Inspiration

Have no fear mad mole. It’s thorough and insightful research like yours that will insure AP valves or Ambient Pressure Diving or whoever the Manufacturer du jour is will continue to thrive as a producer of quality life support equipment.

check out

http://www.wkpp.org/sponsors.htm

Are you likely to bite the hand that feeds you?

Fret not over the sponsorship issue and the WKPP, you couldn’t pay the divers enough to go into that cave using another rebreather. It’s one of the reasons all of the dives are done by divers using all of their own equipment.

 

[nickjb]

This bit of GI3's seminar (here: http://www.baue.org/library/irvine_baue_talk.html and a load of other places) sprung to mind when I read this thread:

"Audience: Why wouldn't you just use the DS4s, something dry sealed down there?

George: Well we want to use those regs on the bottles and breathe them. Scubapro sold us regs super cheap so we bought a ton of them and we use them on the staged tanks.

Audience: If you had a chance of changing that stuff out for something would you?

George: Well if I had my druthers yeah, I'd get Apeks regulators."

I wonder if he got a good deal on the RB80?