Checklists in Rebreather Diving

[Wibble]

AI pressure transmitters on a Nerd. Inject O2 or Dil and you see the pressure change.

With an orifice your O2 will drop to zero if the valve is off. (Also overnight if you left it open!)

 

[rddvet]

Odd how some people like to dive CCR with the O2 & dil valves at the top of the unit. Crunchtastic place to hit the roof or edges.

Do you run into stuff with your doubles valves? It’s no different. The fathom has 1000s of cave dives on them because that’s what they were built for. Fathoms come valves up for onboard tanks. The unit was built by the guy with world record cave dives. If bashing valves into a ceiling is a concern he wouldn’t have built it the way he did. If you’re bashing ccr tanks in he ceiling you would in doubles too and that’s a skills issue.

 

[berndo]

The disadvantage in doing a prebreathe is the time and discomfort ...

And when you read this out loud to yourself, it still makes sense?
In a time consuming hobby to safe a couple of minutes for a safety check? Really?

I get into my unit and go through my predive checklist which is in my wetnotes while sitting down and breathing... not sure what part of this would cause you discomfort.

I'm pretty sure all the people who got in accidents also thought cutting corners wouldn't be an issue. I guess it can't happen to you...

But not checking valves was also a problem with one of the cave accidents last year, and this was on oc.

Which accident was that?

 

[tomfcrist]

If you’re bashing ccr tanks in he ceiling you would in doubles too and that’s a skills issue.

Or a going into tight cave issue in BM vs SM.

 

[Germie]

And when you read this out loud to yourself, it still makes sense?
In a time consuming hobby to safe a couple of minutes for a safety check? Really?

I get into my unit and go through my predive checklist which is in my wetnotes while sitting down and breathing... not sure what part of this would cause you discomfort.

I'm pretty sure all the people who got in accidents also thought cutting corners wouldn't be an issue. I guess it can't happen to you...


Which accident was that?

The one from last year. I cannot tell all details in public. It was a diver with 25 years experience and sadly made more than 1 mistake (together with his ccr teammate). But a lot can be found with google I think.

 

[Germie]

Or a going into tight cave issue in BM vs SM.

True, but most times my Alibox hits the ceiling first then, not the cylinders, haha. There are a lot of scratches on that box, not that much on my cylinders (but on my twinsets a lot).
Getting in the Truffe cave is possible with a twinset, but it is impossible not to hit the ceiling (and your boobs and stomach are going over the floor )

 

[tomfcrist]

True, but most times my Alibox hits the ceiling first then, not the cylinders, haha. There are a lot of scratches on that box, not that much on my cylinders (but on my twinsets a lot).
Getting in the Truffe cave is possible with a twinset, but it is impossible not to hit the ceiling (and your boobs and stomach are going over the floor )

All that said…I’ve picked up plenty of broken valve wheels in pretty large cave. I don’t think I’ve dove Ginnie once without grabbing someone’s broken gear/trash off the floor in passage big enough to drive a truck through.

 

[Marie13]

I’ve been using the standard KISS checklist. I need to tweak it.

 

[rddvet]

Getting in the Truffe cave is possible with a twinset, but it is impossible not to hit the ceiling (and your boobs and stomach are going over the floor )

That’s why the DIR rake is always there. Or should be there if somebody doesn’t steal it. First time I dove truffe was about 11 years ago before sm was very common in France. A guy watched us zip right into truffle and had to stick around till the end of our dive to talk our ear off about how he raked for 3 minutes and still struggled to get in.
Now you see sm everywhere I’m the Lot.

 

[justinthedeeps]

One of the modifications I did to the rEvo checklist was change when the O2 opens up.
Original does
Check ADV
Inflate wing

I once had an issue with those steps. Got on the loop, sucked it down, hit the ADV and got something. On the loop, stay there. Wing inflate, quick connect wasn't connected. Standing in waist deep water to avoid overheating. Weight is on my back, quick connect isn't connecting quickly, what's that flashing red? PPO2? Why is it flashing read at 0.10? Bail! Oh, on the surface. Mouthpiece out, calmly take several deep breaths. WTF? I'm still several steps away from turning the O2 on.

So my new checklist goes from
'Check ADV' directly to 'Open O2'.
Shearwater is already on, so if I had a stumble just after the Check ADV the Shearwater will be firing the solenoid adding O2. The time on the loop without functional O2 is now only a moment to check the ADV function.

Sometime you might need to revise the sequence the steps happen, not just that they are there.

Similarly the JJ-CCR checklist suggests closing the diluent and oxygen valves during the negative check, then re-opening them.

I see no reason to close the close the oxygen valve. I want my negative to be good enough that it is not mysteriously drawing oxygen through the solenoid or MAV.

I modified my negative check to keep both valves open, but close my diluent ADV slider. To end the negative, I re-open the ADV slider. Yay, another component checked 'for free.' Would rather have an ADV mistakenly left closed than one or both cylinders mistakenly left closed.