2 buddies on different gas OK?

[Mark Chase]

Many moons ago I was diving a wall in the red sea using 36% Nitrox. My buddy was on air. An eagle ray was spotted below us and he dropped down to 45m to get a closer look. He couldn’t understand why I was hovering at 35m and waving at him to come back up. Back on the boat it was a dohhh moment for the very embarrassed dive buddy. We had dropped to 50 on previous dives so he didn’t understand my problem. I had told him I was on nitrox and we had a max 30m plan but he was apparently a big fan of eagle rays and forgot in the excitement.  

In UK conditions that would have ended in a couple of solo divers

As far as 02 tox is concerned you would rely have to take the piss to get a tox hit on 32 or 36%Nitrox Even staying at 35 for 10mins and doing 40mins at 30m I would only just tip over the 100% CNS figure.

ATB

Mark Chase

[Finless]

Don't forget the ox tox does not happen immediately - you would have plenty of time to do a quick bounce to retrieve someone.

Due to my complete cock up a few years ago (explained previously) I was breathing 80% O2 on descent to and at 30 mtrs for a few minutes = ppO2 at 30m of 3.2b    .

[And]

Originally Posted by [b

Quote[/b] (Timing @ Mar. 17 2004,16:48)]The long and short of it is that Andy is plain wrong.

<font color='#000080'>Hi

How can Andy possibly be 'wrong'? There is no right and wrong. He just chooses to do it that way. If it is down to him when given the responsibility of pairing divers up thats the way he would do it. BSAC, although not having specific 'rules' do have separate log sheets for nitrox divers and it is discussed on the nitrox courses or it was at mine.

I don't really understand what the fuss is about. There are good reasons for not pairing a nitrox diver with an inexperienced diver who is on air.

There is also no reason why a nitrox diver cannot dive with an air diver if they both plan the dive and dive the plan and both divers plan accordingly.

If you are saying that you do not consider the gasses used when pairing buddies then that is plain nonsense. It must be considered and then a decision made as well as considering experience, qualifications, air consumption, equipment and all the other stuff that a Dive Leader considers when marshalling a branch dive.

I would consider the gasses and, although I would never say never, it would definitely be a factor in pairing divers off.

Kindest Regards

Andy

[Tim Ingmire]

OK, Andy NYE wrote (and I quote) - A Dive Marshall would NEVER pair off a air and nitrox diver together

Thats fairly absolute stuff.

Andy Wetlettuce then writes  
&quot;How can Andy be possibly 'Wrong'.&quot; quickly followed by &quot;There is also no reason why a nitrox diver cannot dive with an air diver if they both plan the dive and dive the plan and both divers plan accordingly.&quot;.

So, Andy you've answered your own question - and it seems we agree.

I don't care what Andy Nye chooses to do but he wasn't saying anything about what he chooses to do - by laying down a 'law' like this is the kind of BS that turns people off BSAC - its not even a position that the BSAC take.

Yes there are good reasons for not pairing a Nitrox and Air divers in some circumstance but certainly not all.  That's what makes a good DM, knowing the right decisions to make in a given situation, not blindly following some made up rule - we agree again.

Oh, and where did I say that I wouldn't consider a buddy pair's gasses?

I would imagine that the log sheet thing is just one of simplicity and convenience and actually reflects nothing much in particular.  There's nothing to say that buddy pairs have to be logged on the same sheet.

[Andy the Coastie]

<font color='#0000FF'>Thats me MATT,,,,,,, I'm Andy NYE ,,,,,, and i'm trying my hardest to get hold of a mate who has my BSAC books, it clearly states in there somewhere , that AIR and NITROX divers should never be paired off , same as a diver on tables and diver on computer....

Andy

[Andy the Coastie]

<font color='#0000FF'>Timing

Originally Posted by [b

Quote[/b] ]I don't care what Andy Nye chooses to do but he wasn't saying anything about what he chooses to do - by laying down a 'law' like this is the kind of BS that turns people off BSAC - its not even a position that the BSAC take.

When BSAC took the in-house training of advanced diver away from a lot of clubs that didn't have instructors to teach most of the new sdc's...... one of our divers went and did the DIVE MARSHALL PLANNING COURSE a whole weekend thing.

When he came back to the club , there was a big ruck as D/O put an air diver with a diver on nitrox,,,,,,, OUT came the paperwork on the following club night , and n clear BLACK &amp; WHITE it stated &quot; Air divers will not be paired off with a nitrox diver &quot;.....

Now the reason i had put that on the instructor forum is , that some of the sports diver exam papers are giving question , and when a student is marking his paper and is wrong , from the multi guess answers , it is a totally different wording in the books that bsac hand out ....

Andy

[Tim Ingmire]

New Student notes from Sport Diver level ST6 pg 94.

I quote

&quot;Dive Planning

If diving on air buddied by a Nitrox diver:
The decompression schedule is dictated by the air diver
The maximum operating depth (MOD) is dictated by the Nitrox diver's gas mix
This obviously needs to be incorporated within dive planning.&quot;

Also, AIUI when diver with a computer dives with a computerless buddy, the plan is dictated by the table not the computer.

Andy N, sorry mate didn't mean to be disrespectful I hope it didn't come across like that. &nbsp;Apologies if it did.

Personally, I would DEMAND AN APOLOGY. &nbsp;We haven't have one of these for ages.

[Tim Ingmire]

Andy, our posts seem to have crossed.

I have to agree on the difference in the BSAC training materials. &nbsp;I too was caught out by the ppO2 of 1.44 thing during my exam - there was another question and answer combo which was nonsense (can't remember which now). &nbsp;I can easily see where this confusion would arise given the different versions of the instructor material that's probably out there.

Interestingly, &nbsp;I don't recall any mention of OxTox in any of the DL student notes - ok it maybe covered in the Nitrox course but a student could easily get to do DL without having done the nitrox course. &nbsp;How the hell are you supposed to be able to confidently DM nitrox divers when you don't even know that OxTox exists or is a risk?

[Fiona]

Originally Posted by [b

Quote[/b] (Andy the Commie 2 @ Mar. 17 2004,18:37)]&quot; Air divers will not be paired off with a nitrox diver &quot;.....

Andy

<font color='#0000FF'>Well in that case I can't dive with anyone from my club, as I am the only person who ALWAYS dives nitrox. &nbsp;

To answer a previous question, establish the depth first and then do the mix. &nbsp;More often than that, I use 36% as this suits most of my diving, there will be very few exceptions, most recently last week in Mull, diving the Rhondo depth to bottom about 50 metres plan no more than 35 metres, actual depth reached 34.1 mix 28%

[MATTBIN]

Andy (NYE) I said at the beginning I wasnt having a pop at Bsac, by inference that also means those that posted. I was interested to know why a Nitrox/Air buddy pair was a no-no. I dont post on the Bsac forum anymore as I'm no longer a member of Bsac. I hope you understand the question was raised (on here) in search of an answer we could all use. I dive Nitrox often, so wanted to know why I shouldnt dive with an Air buddy, generally I would say my question has been answered. If I decide to dive with an Air buddy I now appreciate the information he needs from me to make the plan safe.
Fiona good point about planning the dive mix to the bottom depth, just in case.

Rgds
Matt