CCR Planning a diluent mix

[Garry Whyke]

Planning for an 80 mtr dive off Cornwall in a few weeks time has certainly got me thinking of the advantages and disadvantages of selecting a diluent mix and associated bail out mixes.

Regarding the diluent mix, IANTD recommend keeping the PPO2 of the dil below a PPO2 of 1 bar, the reason being that this would facilitate the impact of the dil flush where there is a high PPO2.

I was talking to a TDI Instructor who prefers higher PPO2's approaching and sometimes just over the 1.3 set point. His view being that it would give him a good PPO2 to minimise deco obligations at 80 mtrs depths, should he need to work his way back to the shot in semi closed mode. Yes it would take longer to dil flush down, but this is something he accepts.

My personal view is the former, but I can see the guys logic.

I'd be interested to hear the views of those who have been there and done it.

Cheers

............. Garry

[Mark Tuttle]

My preference is to use a dil that gives PO2 of 1 at depth.

In my humble opinion, a dil flush at 80m is about survival, it's probably best not to compromise your chances for the relative luxury of shortening your stop times by a few minutes, should you have to SCR it up to the surface.

But I am always open to new ideas...

cheers

[mike etheredge]

Did you not cover this on your course,and do a 80 metre dive. Asking these basic questions on a forum is very worrying. Seek the advice from your instructor, after all you have paid him enough.

[David Walker]

Did you not cover this on your course,and do a 80 metre dive. Asking these basic questions on a forum is very worrying. Seek the advice from your instructor, after all you have paid him enough.

If you read his post he already has the views of both TDI and IANTD instructors - and the advice varies. Since there is no "one right way", he's asking for advice / suggestions / reasons / justification for the various different approaches, which is what this forum is for.

In fact, i'd go as far as saying that i'd be more concerned about people who just take what their instructor says as gospel, and ignores any conflicting information / advice without having fully considered all of the other possible options.

David

[mike etheredge]

Or he read a book and talked to an instructor in the pub.....

[Nigel Hewitt]

Or he read a book and talked to an instructor in the pub.....Works for me.

[Janos]

Did you not cover this on your course,and do a 80 metre dive. Asking these basic questions on a forum is very worrying. Seek the advice from your instructor, after all you have paid him enough.

I don't think it's a basic question.

I know a fair few RB Instructors who favour both routes.

Me? I prefer a high-ish ppO2 as I take plenty of bailout.

Janos

[David Walker]

Works for me.

Yep, me to!

Talking to an instructor in the pub - well thats where I prefer we have most of our discussions, a very good way to spend time learning from instructors. Assuming they haven't had 20 pints at the time, why is an instructor incapable of teaching you something when they're in a pub?

Reading a book - well now, must be terrible, learning from books! Books which, incidentally, are something which come with nearly all courses, so they can't be that bad!

Please Mike, explain what is wrong with learning something from someone you haven't paid? Do you actually advocate that they're only correct if you've paid them money for the information - everyone else is wrong so there's no point asking?

David

[Garry Whyke]

Read books - Yep
Learned from the course - Yep
Talked to CCR Mixed Gas Instructors in the pub - Yep
Listened to alternative viewpoints on forums - Yep
Web surfed for views - Yep
Discussed and debated alternative viewpoints and reasons for the approaches with other CCR mixed gas divers in the pub- Yep.

Mike, suggest you re-read my posting I am not asking how to carry out planning for an 80 mtr dive I am inviting comments on different approaches adopted by some CCR Mixed Gas Instructors which IS the purpose of the forum.

Thanks for all the constructive posts made anyway.

Cheers

.......... Garry

[Nick Kay]

Look he's a YBOD diver

He's just looking for alternate ways of killing himself :p

[Garry Whyke]

It could be worse. I could be diving one of the B&Q jobbies. What do they call them??

Ohh yes, thats it a 'Submatix! lol.

.............. Garry

[Nigel Hewitt]

It could be worse. I could be diving one of the B&Q jobbies. What do they call them??

Ohh yes, thats it a 'Submatix!
<admiration!>

You're a braver man than I am.
And I dive an IDA64...