Dual Rebreathers?

[mr_v]

The chop makes a great deco rebreather and I've played with it a little bit for this purpose on cave dives.

I am intrigued by the concept. However, how would operations look like? Would you drop it off right before the location where you'd typically have deco gas and leave it running at a high set point? Or do you take it along with you, but that would make it a BOB.

 

[Dsix36]

Is your BOB posted anywhere? I am interested to see pictures or more information about it.

Not since Rebreather World went down.

 

[GiraffeMarineSalvage]

Not since Rebreather World went down.

Might be able to find it on the Wayback Machine?

 

[kensuf]

What was your other rebreather?

Fathom or Meg.

 

[Fat old english bloke]

I am intrigued by the concept. However, how would operations look like? Would you drop it off right before the location where you'd typically have deco gas and leave it running at a high set point? Or do you take it along with you, but that would make it a BOB.

I’ve thought about doing similar with my CM one day if the number of bottle gets too unruly.

It would seem most logical to stow on the line, as per any deco bailout bottle, with the deco profile being run from my back-up computer - assuming I’ve bailed out and would then bail-on (in..?) when I reached the deco CCR. SP on the back-up would obviously match whatever I’m diving on each unit.

I’d be very keen to know what experienced folk on here actually do in reality.

 

[mr_v]

I’ve thought about doing similar with my CM one day if the number of bottle gets too unruly.

It would seem most logical to stow on the line, as per any deco bailout bottle, with the deco profile being run from my back-up computer - assuming I’ve bailed out and would then bail-on (in..?) when I reached the deco CCR. SP on the back-up would obviously match whatever I’m diving on each unit.

I’d be very keen to know what experienced folk on here actually do in reality.

Is your chestmount unit self-contained? If not, it will probably be useful only to you and divers with the same configuration, unless you want an O2-only unit you can pass around. A self-contained unit like Liberty sidemount may be a better option if you need dil and O2. Also, you could pass it around to other divers, if needed, provided that they know how to clear/open DSV, read PPO2 monitor, and figure out the optimal breathing position.

I am getting to the point where a BO/deco CCR may make sense and looking at Liberty sidemount for that purpose. Will keep you posted.

 

[Fat old english bloke]

Is your chestmount unit self-contained? If not, it will probably be useful only to you and divers with the same configuration, unless you want an O2-only unit you can pass around. A self-contained unit like Liberty sidemount may be a better option if you need dil and O2. Also, you could pass it around to other divers, if needed, provided that they know how to clear/open DSV, read PPO2 monitor, and figure out the optimal breathing position.

I am getting to the point where a BO/deco CCR may make sense and looking at Liberty sidemount for that purpose. Will keep you posted

It is O2 only, off board dil. If mine was for team use we’d ensure everyone has the appropriate fitting to plug in their dil if needed.

Liberty or a Flex would certainly make much more sense for a full on BOB.

Definitely interested in your BOB journey.

 

[justinthedeeps]

The guys in Bali include a very active instructor on several units who are occasionally checking out DPV dives well below 100 metres as a shore dive, which is apparently routine as long as adverse longshore and downslope currents etc can be avoided.

Even with plenty of good help shuttling cylinders etc to and from shore, there would be theoretical and operational benefits to the BOB approach, -if- well practiced/maintained/executed with enough proactive and wary discipline to avoid an error chain

Personally I would be afraid of mismanaging or neglecting the 'always breathable' BOB loop status at all times, especially under stressful or challenging conditions. Perhaps also have an open circuit cylinder of deep bailout mix available at all times on a BOV or necklace reg? Or else some way to get some idiot-proof safe open circuit diluent immediately at any time, should I stuff up something else an need precious survivable minutes to maybe sort out the fancier plan?

 

[alex_nr]

The guys in Bali include a very active instructor on several units who are occasionally checking out DPV dives well below 100 metres as a shore dive, which is apparently routine as long as adverse longshore and downslope currents etc can be avoided.

Even with plenty of good help shuttling cylinders etc to and from shore, there would be theoretical and operational benefits to the BOB approach, -if- well practiced/maintained/executed with enough proactive and wary discipline to avoid an error chain

Personally I would be afraid of mismanaging or neglecting the 'always breathable' BOB loop status at all times, especially under stressful or challenging conditions. Perhaps also have an open circuit cylinder of deep bailout mix available at all times on a BOV or necklace reg? Or else some way to get some idiot-proof safe open circuit diluent immediately at any time, should I stuff up something else an need precious survivable minutes to maybe sort out the fancier plan?

The way I was taught/do is that I have one cylinder of ‘sanity gas’ that I first switch to (BOV or necklace) before going over to BO machine in a real scenario. Which may be so-so, as the normal switch when switching loops is direct/without the OC step.

Could be argued that the fact that you have to switch to BO machine several times during a dive is more practice than most get bailing out to OC, but many other things that can be said against as well. I am fully aware that a propper CO2 hit at 100m with a BO machine has awful odds for example.