Looks like I will soon be joining the ranks of the bubble-less. I will very soon be getting a Hollis Prism2 CCR rebreather. I realize that it will take a lot of learning & discipline to learn it, but I'm feeling up to the challenge.
Can't wait! A new era of diving for me!
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drrich2
Contributor
I'll be interested to hear what you think of it in practice. I've seen threads on rebreathers, including diver deaths on them. If I understand correctly, it's possible to have a malfunction-related gas abnormality and basically drift off to sleep and drown. I am jealous of the long bottom times I hear about with them, though, and the lack of bubbles to frighten animals.
My question would be, once you're 'up and running' and have some practical experience with it, how does the 'mindfulness level/attention' requirement for diving a rebreather compare to that required in open circuit diving (and I assume technical?)? How much does it start to feel like an exercise in engineering, or at least complex piloting, compared to 'just' diving?
I'm not knocking rebreathers; just curious about the practical real world practical experience of using one (as opposed to just technical spec.s & what they can do).
Richard.
My question would be, once you're 'up and running' and have some practical experience with it, how does the 'mindfulness level/attention' requirement for diving a rebreather compare to that required in open circuit diving (and I assume technical?)? How much does it start to feel like an exercise in engineering, or at least complex piloting, compared to 'just' diving?
I'm not knocking rebreathers; just curious about the practical real world practical experience of using one (as opposed to just technical spec.s & what they can do).
Richard.
OP
I have been around Larry, who has been diving the unit for several months. At first he says I will likely hate the unit, as I learn to adjust to it. A lot of rebreather diving goes against what most divers know, but once used to it, Larry says I'll likely become hooked & wonder why I didn't do it earlier. There is a HUGE learning curve.
As for risks, there are multiple things that can go wrong. Hypoxia & CO2 build- up or breakthrough can cause unconsciousness & loss of airway control. The other is oxygen toxicity that, as you know from Nitrox, causes convulsions. Buoyancy control is totally different,... you can not use breathing control to work your buoyancy. There are also other things that can go wrong & cause breathing issues or uncontrolled ascents/ descents & such. Some Rebreather units aremore complex than others. Of the 2 units we sell out of our shop, the Poseidon MK6 is completely electronically controlled. It does its own system checks & if anything is amiss, it will shut down & not let you dive the unit. The Poseidon is more fore the recreational diver. The Poseidon is limited to about 180ft or so. They are great for photographers, as there are no bubbles to scare the fish. In fact, you can swim into a school of fish & they will not spook the fish. For technical applications there are many modifications that must be made to make it suitable.
The Hollis is more along the lines of what I'm looking for. I want a rebreather that I can use for cave & eventually for trimix. The Hollis is already mostly modified to what is needed for cave & the diver can do full technical trimix on it. However, the operator must manually do the checks (chance for human error). Following checklists are a MUST! The diver must also keep a close eye on what his system is doing. As Larry put it,... You have to keep your head out of your a** when diving one of these, as they can be unforgiving, if one is not attentive. Most rebreather divers refer it to piloting or flying their machine(s).
Until I get into the unit & start learning, I can only go off of what other divers have explained to me.
As for risks, there are multiple things that can go wrong. Hypoxia & CO2 build- up or breakthrough can cause unconsciousness & loss of airway control. The other is oxygen toxicity that, as you know from Nitrox, causes convulsions. Buoyancy control is totally different,... you can not use breathing control to work your buoyancy. There are also other things that can go wrong & cause breathing issues or uncontrolled ascents/ descents & such. Some Rebreather units aremore complex than others. Of the 2 units we sell out of our shop, the Poseidon MK6 is completely electronically controlled. It does its own system checks & if anything is amiss, it will shut down & not let you dive the unit. The Poseidon is more fore the recreational diver. The Poseidon is limited to about 180ft or so. They are great for photographers, as there are no bubbles to scare the fish. In fact, you can swim into a school of fish & they will not spook the fish. For technical applications there are many modifications that must be made to make it suitable.
The Hollis is more along the lines of what I'm looking for. I want a rebreather that I can use for cave & eventually for trimix. The Hollis is already mostly modified to what is needed for cave & the diver can do full technical trimix on it. However, the operator must manually do the checks (chance for human error). Following checklists are a MUST! The diver must also keep a close eye on what his system is doing. As Larry put it,... You have to keep your head out of your a** when diving one of these, as they can be unforgiving, if one is not attentive. Most rebreather divers refer it to piloting or flying their machine(s).
Until I get into the unit & start learning, I can only go off of what other divers have explained to me.
KY_BOB
Contributor
You know that I find rebreathers intriguing. I'm sure that the bouyancy is totally different than anything that I have ever dove but can you explain why you can't use breath for depth control? The rebreather doesn't change it's size, does it?. A person with full lungs displaces more water than if their lungs are empty. I'm not doubting you, just wanting to understand.
OP
It's because of the volume of the counterlungs on the unit.
KY_BOB
Contributor
OK, I wasn't thinking about the counter lung, Duh.
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Tammie,
Good for you! a REBREATHER!
It is certainly encouraging to follow your progress into and through the Underwater World...
The activity is certainly adictive ....will consume your life!
\
It has mine and I suspect it has yours..
SDM
Good for you! a REBREATHER!
It is certainly encouraging to follow your progress into and through the Underwater World...
The activity is certainly adictive ....will consume your life!
\
It has mine and I suspect it has yours..
SDM
AfterDark
Contributor
OP
I will begin training on my unit in the coming weeks. I'm totally looking at it differently than before. Although different, I got very humbled by my Cave DPV course. It really got me to thinking how quickly things can go wrong. Yes, I am still going to learn the unit, but I am now thinking on a more cautionary level, than before. That DPV course was a real eye opener for me. I needed that.....
And IMO this is what separates really good/great divers, and especially instructor's, from the herd. The realization and acceptance that there are things that take time. Time to learn, time to absorb, time to get to know intimately before jumping in with both feet, so to speak. Too bad so many think rushing through class after class is the way to do it.
And even worse that agencies allow people to.
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