Hello and welcome to our community! Is this your first visit?
Just for shits and giggles I might try it on the surface and see how much flushing is needed.
It'll burn less brain cells than the rest of a Friday evening anyway.
As a CCR curious OC diver I've followed these threads with great interest.
Question: why would one *not* plan to carry all the independent bailout your plan needs?
John's plan makes sense in my little brain: carry three separate tins that will definitely get you the hell out of Dodge without getting bent and without relying on the "dead" box. Agreed, failures happen where you can get back on the box later on (I'm thinking of a dil or cell problem) and then run it as an SCR. However, if it's a catastrophic failure, then there's no problems as you've everything you need and you can just chill out whilst blowing bubbles.
As I understand it, as you get much deeper, you can't carry enough bailout. If a bailout rebreather isn't available, then it's down to team bailouts or doing anything to extend your deco time, including chugging the 3ltr O2 even if it's breathing it out of the counterlung.
I don't think anyone is advocating not taking enough gas Paulo is just looking at the other options available that could extend the gas.
From my pov though I looked at SCR but rapidly discounted it as a personal option due to the potential uncertainty of gas content, task loading, physical effort, impact on deco obligation etc.
Maybe if I practised SCR more I may feel more comfortable with it, but oc seems safer and easier.
I am certain I wouldn't want to risk it off a wet scrubber though due to the risk of pharyngeal spasm if the worst happened, and reduction in scrubbing performance.
I'd be a bit nervy already at the very least if I had to bail.
With time it is quite easy to become complacent. I've seen many CCR diver who IMHO carry inadequate bailout but this hasn't been a problem as they've never needed it.
Originally Posted by Wibs
The risk with CCR diving is that, if looked after and dived sensible, rebreathers just work. This can mean preparing for failure can become less important.
I am sure others can claim more but, having just checked, the last time I bailed out in anger was in 2011. Since that bit of sloppy maintenance I have done over 600 hours of uneventful CCR. On most of those dives I've carried at least enough bailout to get home but with hindsight it wasn't actually necessary! (I'll not be changing my ways though)
Last edited by dwhitlow; 18-10-2018 at 05:01 PM.
I think SCR can be useful at some points in a bail out plan ,
fixed depth ie getting back to the shot , id not use it on a falling ambient pressure, it the last tool in the box
main thing for me is you have no need to do this 4 or 5 breaths , id be happy just to turn my 7l in to a 14l or 21l
fixed depth back to shot 3 breaths is feeking loads maybe 2 breaths up to 21m
unless your diving Alpine 4/5 breaths is point less ,
and what the chance of all 3 cell going down , scr is worth a play with , but whats your chance of getting just the right failure,
flood or co2 your off unit , scr is not going to cut it,
no way id try pushing gas round my unit with a feeked up scrubber ,
That,s just flying by the seat of your pants , not a plan
Last edited by gobfish1; 18-10-2018 at 05:39 PM.
None diver as of 2018.
You don't need any sorb to do SCR running 4:1 breaths
Originally Posted by JonG
Its pure 02 so no need to use the ADV just manualy inject 02 via kiss valve
The problem with the KISS is it lacks easy flood recovery so in theory you could have a scrubber full of water which makes it impossible to breath.
The good news is KISS are pretty flood resistant due to the lack of connections in its design.
For the situations where the unit is not viable, I have the drop tank. No boat except Loyal Watcher, had its own drop tank. I always took my own pre rigged and ready to drop
Skipper was told to hook out my SMB, clip the tank to the line and throw it overboard
DropTank by markchase8, on Flickr
Because task loading is a big killer of divers
Originally Posted by Wibs
Kitting up with three tanks and diving with three tanks is increased task loading.
Deep bailout is essential
Intermediate bailout is essential
Shallow bailout? You have the option of Pure 02 CCR Blind, SCR Blind, Buddy with gas, Drop tank
You also have the option to do aggressive deco on available gas, or to empty available gas, get on the boat and get on 02
Two tanks + a small tank would be my last choice just after running 7ltr back tanks with a reg on the 02. or even 3ltr back tanks with 02 blown to 270bar and a reg on it.
But each to their own
On the plus side, when you do have to carry three tanks you have had the practice. But TBH when I have to carry three its three + a drop tank, so you would be on four.
Why the aversion to my genius plan Mark?
Nothing wrong with your perfectly acceptable plan
Originally Posted by JonG
Like you I now would plan 80/80 deco and 100/100 Poo fan interface deco. I also plan deco on a SAC which whilst low by many peoples standards, is still 100% over my deco SAC average for the deep bits and 50% over my deco average for the intermediate and shallow bits.
My only response to your post was RE Pure 02 SCR on the kiss as you mentioned how stiff the ADV was and your comment about the boat not having a drop tank.
Not only do I not expect the boat to have a drop tank, Id much rather use my tank, my regs, my gas. which haven't sat on the boat for two years unused and was fill checked the day before the dive.
I cant fault your computer generated plans nor your enthusiasm to premeditate all the issues relating to bailout. I did the same for many years.
I have also tried most configs and even had a near suicidal attempt at teem bailout.
My highly bias conclusion was for any dive that needed three tanks, I want a deco station
If you have a deco station the drop tank / shared gas thing becomes very very simple.
One of the main reasons I am not doing this stuff much anymore is the loss of my personal group of like minded divers
You may become a competent three + tank diver who can do it without breaking a sweat.
I personally never did and always found it uncomfortable and fiddly. And Fiddly is not a good thing.
A three tank bailout dive was something that took extra care, extra support and better conditions not just in terms of sea conditions but also in terms of kitting up space and deck support pre and post dive.
I did it only when I had to (80m+ 3-4 hour runtimes)
That said dives 60-80m without a deco station? with a skipper I didn't know? Maybe id decide three tanks was the way to go for that dive.
I only offer an opinion, and I am sure better divers than me will have a different one
The only justification I have for my opinion is a lot of dives in that range where three tanks becomes a consideration and my personal feelings as a result of that experience.
I am also against all tanks left. Both Howard and Janos my dive buddies for the last few years doing the deeper stuff dived tanks left.
I really like tanks left....in the water out of it it's a pita to the point where I am now diving left right with the 3l on top of the deep bailout on the left if/when needed.
It is just easier kitting up, getting to the platform, getting back out etc. and physical loading is symmetrical which may count for something as you transition from horizontal and suspended to vertical and under the influence of gravity.
Next wreck trip is remembrance weekend off Eyemouth, fingers crossed for good weather.