Cross over courses - fact or fiction?

Mike

Must say I have never understood the emphasis on shallow dives for a new CCR diver - yes they are good for practicing skills, but unless you run as an O2 rebreather, are they any safer?

OC, it makes sense to do stuff shallow early on, because if you are ooa, you can do the bolt for the big free air supply. But on a CCR, a OOA is not a likely failure mode... Neither hypoxia, hyperoxia or hypercapnia are going to be solved by bolting to the surface, so why is shallow safer?

Again, I'm interested (honestly, as I'm a newish rebreather diver) why a new rebreather diver is safer at 10m than at 50m? Either way, if things go badly enough wrong, I'm getting off the loop, and once on OC I'm pretty happy at either depth - I don't feel one is safer than the other. What makes someone safer at 10m on air than at 50m on normoxic trimix? Deco is not an issue, as bolting to the surface isn't going to happen regardless, so I'll deco out OC, no problem.

I'd also add that the shallow dives I do are mostly with AOW types, whereas the deeper dives are generally with other CCR divers, or at least experienced OC types, so to be honest if I did pass out, there is more chance that I'd make it back to the surface on a deep dive.

I still don't see any logical reason why you think a CCR diver you have certified is safe at 10m, but not at 50m on a normoxic mix?

BTW - I mean this as a general question, not just directed at Phi.

Mike

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decoweenie

Shallow doesn't necessary mean in the O2 CCR range (6m max), I was referring to the no-deco zone (whatever that means to different people) as shallow.

Another thing to remember that not all new CCR divers are experienced OC divers, or OC trimix divers. So when making guidelines/policy/etc, it is the lowest common denominator. For some people, even 60ft/20m is deep.

Also, not everyone diving in the no-deco zone will have more OC-bail-out than the on-board diluent tank. Different beliefs about this issue aside, this is just the fact.

So OOA is still a real issue if someone who is new making a mistake and flood their unit.

IMHO, there are so many little subtleties to be learned as a new CCR divers as far as trim, buoyancy, condensation, gear optimization, etc. that only time on the unit will help. Even just the general comfortable feeling of trusting the unit on a long dives.

There is nothing to be gained by rushing, IMHO.

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rogeringebo

I am looking in to doing a Meg course (crossover) I am already certified to trimix level on CK and hold a Pelagian diver cert...the school claims that the Meg instructor has been told by Leon not to do minimum skills/dives crossovers and they claim that I have to do the full course but with 10% discount.... what do you guys think about that?
Like DrMike, I have nothing against training but is it really something that iI should have to do?
Rodge

Decodiver

Well I charge 550 sterling for a crossover and 850 sterling for a complete Mod 1 on the Meg.

Cheers,

Dave Cooper.

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CCR Training to Mixed Gas in Switzerland, France, UK & Germany on
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Rebreather World Terms & Conditions

JonnyB

I have been talking to different Meg instructors and got prices all of them tell me that Leon has told them that the price will be the same. So all of them charge somewhere arounf 600GBP, now (observe my next statement is probably wrong), i did talk to Leon about doing a crossover and the price i remember was 500USD. So imagine my chock when hearing all the other prices. I will call Leon again and verify, cause i am probably wrong, or outdated, cause i also have an email from the Man, mr. Mount, where he also stated 500USD but that was a while ago. I have invested quite alot of money into my Meg, and all the things around, new computer etc etc and i just cant afford the class right now...

kind regards
Jonny

nigelh

That's rather how I took it.

I confess I ignored the "Air" part of my mod 1 but felt that in sticking to no significant deco I was staying within the 'spirit' of the qualification. I nark badly and I really did not want to be facing a fault on my new rebreather with half my brain off-line due to lack of helium. "No mandatory deco" effectively capped my depth to less than the 40m on the card as short dives aren't my thing but, unless somebody really feels the need to toe the party line, I doubt I will get many complaints.

I think a diver is less safe at 50m than 10m simply because of the decompression implications. As a novice rebreather diver running into a stop without the benefit of a blob or a shot line was a much more complex business than it ever had been before. I confess a lot of my safety stops from those days were a lot more bumpy than I would expect to do now. I am not sure this current fascination with 100 hours is reasonable though. I don't do that in two years. That is just making trimix rebreathers elitist when they are the sensible option.

Anybody got a crossover from YBOD to IDA64 on their books?
Heck an IDA64 manual would be a thing - English a bonus.

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nigelh

dantheman

As you point out, the safety can be debated.

But the buoyancy control development cannot.
As we all know, it takes time, and the more time shallow,
the faster it will come. This will be especially useful later
in maintaining deco stops...
(just had to use him, now that he lives here!!)

Not really an argument for spending all your time shallow,
just a good portion of it.

--dan

decoweenie

Just curious... from which agency is this cert issued ?

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"...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..."

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decoweenie

Jonny,

Does this mean that you have not had your Meg training ?

And have you taken delivery on your Meg yet (looking at your avatar) ?

__________________
"...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..."

- Rebreather World PM

JonnyB

Unfortunatelly yes...

YEAH!!!

/Jonny