Trimix Qualifications on YBOD? Should I?

[MaryS]

hi everyone, I'm a new YD member, but you'd better add me to that RB list.

I'm OC normoxic trimix qualified (IANTD) and TDI CCR Mod 1.

I'm thinking of using trimix in my YBOD shortly, as I've just started doing 40m+ deco dives, and I'm feeling the narcosis. I just wondered what peoples' views are on bothering to get CCR Trimix qualified if you already hold an OC trimix ticket?

Mary S

[wreckweasel]

I've always liked the whole cat/pigeon combo.

1. Do you have any dependents, who would rely on your insurance? (Diving outside training will invalidate this)
2. Does your personal travel/medical insurance cover any gas mix

Other than that, its your lookout. If you're the sort who's capable of self training and are able to be commited enough to do this including ALL your research, then go for it. Theres more than one way to skin a cat.

You need to be able to answer the following though, before attempting a committing mix dive;

You're diving to 70m for 30 mins.

- Whats the ideal drive gas
- What are the ideal bailout gases (Mix and free gas volume)
- Whats your SCR and OC deco schedule
- How will you handle breakthrough at depth
- Your drive gas is 10/52, whats your loop running at a SP of 1.3

Theres loads more, but this is a good starting point The reality is that the in water skills probably represent more of a challenge.

For the record, I've no axe to grind either way. I think theres merit in both options.


/Zak

[Drmike]

Originally Posted by wreckweasel

I've always liked the whole cat/pigeon combo.

1. Do you have any dependents, who would rely on your insurance? (Diving outside training will invalidate this)
2. Does your personal travel/medical insurance cover any gas mix

Other than that, its your lookout. If you're the sort who's capable of self training and are able to be commited enough to do this including ALL your research, then go for it. Theres more than one way to skin a cat.

You need to be able to answer the following though, before attempting a committing mix dive;

You're diving to 70m for 30 mins.

- Whats the ideal drive gas
- What are the ideal bailout gases (Mix and free gas volume)
- Whats your SCR and OC deco schedule
- How will you handle breakthrough at depth
- Your drive gas is 10/52, whats your loop running at a SP of 1.3

Theres loads more, but this is a good starting point The reality is that the in water skills probably represent more of a challenge.

For the record, I've no axe to grind either way. I think theres merit in both options.


/Zak

Good answer!

I had a new Inspiration instructor with a handful of dives on the unit bolt to the surface on OC when his O2 solenoid stuck open on a 25m reef dive!

He was talking about shoving trimix in it and diving the Prince of Wales (68m) cos he didn't see the need to do a mod2 or build up experience.....he doesn't dive the unit anymore - thank god!

(he also didn't reach the no. dives needed to activate instructor status)

It is possible to self teach and that suits some people - but not others.

Personally I would always do the training because whats saved my life on a few occasions was the extras and personal experience sharing that my instructors gave me more than the course material. Plus its a good way to make a new dive buddy! But that's me, others go a different route.

[Mdemon]

This has come up a couple of times recently, here and on the list. I guess there is a group of newbies like me coming through and wondering why all our mix tickets are now useless.

If helium is our friend and narcosis is a bad thing then logic says use the appropriate gas for the depth. So, as you say, it seems sensible to use mix 40+. But, as pointed out, if you have insurance it won't pay out as you don't have the ticket. Don't use mix, die and your dependants get cash. Maybe I/you/we prefer "use mix and live"?

I wonder if TDI could allow combining of courses like you can do Adv Nitrox and Deco Procs together? If I am Adv Trimix OC then I do an extra module at the end of the Basic CCR and go straight onto Normoxic depth certification. Get some dives done and come back for an Advanced CCR Mix course. TDI don't lose out - they get the same number of courses per student. We as divers don't lose out as we get to use trimix safely out of the box, and insured, with our OC mix experience counting for something.

I can't see many people leaping straight past 40m on Dive 1.

[Drmike]

Originally Posted by Mdemon

. I guess there is a group of newbies like me coming through and wondering why all our mix tickets are now useless.
.

Because the OC mix course doesnt teach what is taught on these courses.

The mistake is calling it a CCR trimix course. Yes its trimix but what most of the course is about is how to handle RB specific problems that may be fatal if encountered at diving at trimix depths. The rest of the course is RB specific trimix stuff such as bail out gas planning etc.

They should maybe rename the course Advanced CCR or something, that would stop confusion.

[wreckweasel]

The difference with running mix through the unit isnt really about the breathing mix, its more about failure management, since a failure now is likely to be in a place where you can't just press the off button and go home.

Its a pretty tired debate, if truth be known. Personaly, I feel theres merit to making MOD 1 a course that includes a squirt of helium. The problem is, frankly, theres a lot of CCR divers out there with all the bouyancy control of a brick and minimal understanding of both their rigs and their bailout options.

<shrugs> as I said before, each to their own Some of the better divers I've seen, never did a CCR course.....



/Zak

[MaryS]

Thanks for the answers so far. I think that has a cleared up a few questions for me - that there is value in going on to an "Advanced CCR" course for more practical experience and bail out options, after more experience, but I'm likely to have played around the edges of it on trimix already.

At present, I'm not that interested in real serious deco dives yet. So far, with slow ascents, and some deep stops, my nitrox computer has cleared of deco obligation on the way back up, but it did want me to go straight to 3m initially????

I'm definitely more of the "use the right gas mix and live" ilk. I'm waiting to see what DAN insurance thinks of this approach.

I also have the benefit of probably more theoretical knowledge than most, and access to manufacturers & test houses, as I look after the UK navy's rebreathers for a living. It makes self teaching somewhat easier - i just need the diving experience to apply the knowledge.

happy new year, and may be see you diving sometime
Mary S

[nigelH]

Originally Posted by wreckweasel

The difference with running mix through the unit isnt really about the breathing mix, its more about failure management, since a failure now is likely to be in a place where you can't just press the off button and go home.

Yup. I did mod 2 and I learnt a lot on the course about managing faults on the YBOD. Basically it was about how to save my neck whatever I'm breathing. There were a whole lot of get-out-of-jail free cards to be played running variants of semiclosed mode and the like that I didn't know from any OC course. A bit of maths for helium is easy, it's looking at blank handsets or gauges that shouldn't read zero contents by the dive plan but do that are the hard bits. As it was I went into CELL ERROR on the course 25 minutes into an hour and a half run time at 59.6m (that number is engraved on my memory as it was my deepest dive ever at the time). I learnt a lot on that dive and having the class and an instructor around me helped.

nigelH

[Phoenix]

I've been pondering this one too, my YBOD will be arriving "soon" and I'm basically stuck with doing the IART course due to Instructor/unit availability, this is fine but IART insist in dragging the training out to 3 courses. I really don't see the point in their "extended range" course, 60m with no He but it will be a prerequisite for their trimix course. I expect I'll put He in when I'm ready as already OC trained and just not push the depth until I feel comfortable.

Ian

[daz]

Originally Posted by MaryS

hi everyone, I'm a new YD member, but you'd better add me to that RB list.

I'm OC normoxic trimix qualified (IANTD) and TDI CCR Mod 1.

I'm thinking of using trimix in my YBOD shortly, as I've just started doing 40m+ deco dives, and I'm feeling the narcosis. I just wondered what peoples' views are on bothering to get CCR Trimix qualified if you already hold an OC trimix ticket?

Mary S

Don't be such a bloody tart

I'd be willing to risk buddying with you as a narcosis benchmark but I seem to give the impression of being narked on anything over 5m

Daz

P.S I reckon with your enquiring mind and background you will be pretty much ok on the self learning route.