REC TriMix

[mempilot]

I don't think this is correct. The tech diver course and the normoxic course may be combined. Even leaving rec trimix out of it you can get through the entire IANTD progression without diving air/nitrox beyond recreational depths.

Mike, you may be right, but that is what I was told when I went through the courses. I even pulled up IANTD's Standards and Procedures documents yesterday to make sure before I posted. They are somewhat ambiguous in their wording, which may leave the door open for instructor interpretation. That may allow some combination and credit not specifically lined out in the S&P.

 

[badgers]

Agreed 100%.

Helium is expensive, but, for recreational dives, you don't need that much.

Example:

Steel 95cf tank at 2640psi

Dive depth(MOD): 120
Target END: 80
Target PO2: 1.4

Best Mix would be 30/12/58

385 psi of O2
317 psi of He
1938 psi of Air

Assuming cost of gas is $0.22 for O2, $0.55 for He, and $3.00 for an airfill, then the cost of this fill would be approximately:

$15.00

Not that much more than an ean30 fill.

this is exactly what I am looking for, not a lot of helium, just enough for an extra margin of safety. I am not even looking to extend my bottom time since I dive an AL 80 and I will usually run low on "air" before I hit my no decompression limit.
I think my diving is different from the "mainstream" member of scubaboard. I am not looking to go deeper, extend my bottom time, or get into a different equipment rig. I want to take a light BC with an AL 80 and go down with a group of people. I want to add 10-15% he for a greater margin of safety. I am still going to come up with the rest of the group. I would say that most of my trips the group has some divers on AIR. Even with Nitrox I am not staying down longer then what the air tables indicate, because of the group. I have only been on 3 trips where all of us were on Nitrox.
Just adding 10% helium is not a huge expense, and it seems like the best insurance money I could spend.

I have sent an email out to the shipwrekadventures to see what they have to say.
thank you for your time and have a good day

 

[diverbrian]

Mike, you may be right, but that is what I was told when I went through the courses. I even pulled up IANTD's Standards and Procedures documents yesterday to make sure before I posted. They are somewhat ambiguous in their wording, which may leave the door open for instructor interpretation. That may allow some combination and credit not specifically lined out in the S&P.

My Normoxic and Tech course is combined. All my dives are on helium mixes for the course, but I was given the option of doing the primary skills dives on nitrox. I declined and ponied up for the mix.

I would have had the option of just taking a technical diver course which involved straight air, but neither my instructor nor believe in that.

PS, the cost of a helium fill...

2 x 130 cu. ft. tanks,

30 to 40 percent helium

78 cu. ft. to 104 cu. ft

(.5 cu. ft. for He) means

$39.00 to $54.00 for He.

$25.00 for nitrox topoff to desired mix (dive shop has EAN36 premix which means that O2 does not need to be added).

We are looking at $64 to $79.00 a fill for my double 130's for what I am doing.

 

[MikeFerrara]

Mike, you may be right, but that is what I was told when I went through the courses. I even pulled up IANTD's Standards and Procedures documents yesterday to make sure before I posted. They are somewhat ambiguous in their wording, which may leave the door open for instructor interpretation. That may allow some combination and credit not specifically lined out in the S&P.

There are lots of instructors teaching the tech diver class who aren't trimix instructors so they can't combine it with normoxic trimix. I know several instructors who just don't like the idea...there are those still around that think 1, that you should learn deepish diving on air and 2, that 170 just isn't too deep for air in the first place.

The two courses were designed to go together though and even use the same text book. It's before my time with IANTD but the course that the tech diver course replaced was I believe the course commonly refered to as "deep air" and I think the actual name was "technical nitrox".

I went through it like lots of others though and was out doing 170 ft dives on air.

40 fathom grotto at about 170ish I see my wife looking at her SPG. Then I see her counting on her fingers. Then she drops the SPG and just seems to be facinated with studying her fingers...front, back, inbetween and how they can wiggle. Then I take her by the hand and lead her up. There are narcosis stories about me too but I'm not telling those.

 

[mempilot]

Mike,

Totally agree. For the last couple of years, I have been logging dives in the 150 to 180 range on air/nitrox, with one stupid dive to 202 fsw.

When I started using mix, I started remembering dives. That really scared me. I'm a believer. Can air dives be done past 170? Sure. Is it safe? It's all relative. Would I do it again now? Heck no. I just thank the guy upstairs that I didn't have a real emergency while narc'd.

I did a mix dive to 140 today that I used to dive on nitrox. The wreck looks completely different and a lot smaller now. I can actually write up a nice dive report this time.

As for IANTD, their S&P is a bit messy as it relates to all the courses and their prereq's. They need one of those nifty multi-color charts like PADI has to lay it all out.

Anyway, my recommendation to anyone looking to go deep, or even spend a lot of time in the moderate depths, is to look into Adv. Recreational Trimix. If tech is the route, then move on to Normoxic and Hypoxic.

 

[Tom Yerian]

how well does say rec trimix from iantd cross over to another agency if you wanted to get qualified later for deeper diving?

If you are not going to dive below 200fsw take the normoxic course,but if you will be diving over 200fsw, skip the normoxic course and take the full trimix course. If I was in your position, I would go FULL TRIMIX,save yourself time and a lot of money!!!That way you are covered for any depth of diving weather you limit yourself to 200fsw or not , at least you will be ready for any up coming adventures and not be caught with your drysuit down!!!

yid: Capt. Tom Yerian

 

[mempilot]

If you are not going to dive below 200fsw take the normoxic course,but if you will be diving over 200fsw, skip the normoxic course and take the full trimix course. If I was in your position, I would go FULL TRIMIX,save yourself time and a lot of money!!!That way you are covered for any depth of diving weather you limit yourself to 200fsw or not , at least you will be ready for any up coming adventures and not be caught with your drysuit down!!!

yid: Capt. Tom Yerian

Tom,

What agency lets you skip normoxic for full trimix? The curriculems I'm aware of either require it as a prereq or combine the two.

 

[Tom Yerian]

Tom,

What agency lets you skip normoxic for full trimix? The curriculems I'm aware of either require it as a prereq or combine the two.

I guess I am an old timer, when trimix was first offered, it was full gas, using Hypoxic mixes for deep diving. And I guess as usual someone figured,to make more money lets split up and create all kinds of new name certifications for an increased profit margin!When I was with Billy Deans in key west he taught full gas trimix in the beginning. The certs, normoxic trmx.,or intermediate trmx wasn't around, it was a later development. There basically the same! So rather than get the interested explorer at that time paying for one cert that covered everything anyway, powers that be said ,''split the course into two separate courses,and we can get twice as much money!'' The same as all the courses that have been developed over time. They are there to make more money and have a whole bunch of fancy c-cards to offer. Well, I guess I reveal my age somewhat! Remember, Billy instituted the first tmix course in the country as an accepted tech. course. His Idea of a tech course was ''oxygen management'' as a definition tech. dive ops.....Ok?

yid: Capt. Tom

 

[diverbrian]

I guess I am an old timer, when trimix was first offered, it was full gas, using Hypoxic mixes for deep diving. And I guess as usual someone figured,to make more money lets split up and create all kinds of new name certifications for an increased profit margin!When I was with Billy Deans in key west he taught full gas trimix in the beginning. The certs, normoxic trmx.,or intermediate trmx wasn't around, it was a later development. There basically the same! So rather than get the interested explorer at that time paying for one cert that covered everything anyway, powers that be said ,''split the course into two separate courses,and we can get twice as much money!'' The same as all the courses that have been developed over time. They are there to make more money and have a whole bunch of fancy c-cards to offer. Well, I guess I reveal my age somewhat! Remember, Billy instituted the first tmix course in the country as an accepted tech. course. His Idea of a tech course was ''oxygen management'' as a definition tech. dive ops.....Ok?

yid: Capt. Tom

Actually, I have noticed one major difference. The normoxic or "intermediate" doesn't require a travel gas. I am using a travel gas because I like to get off that helium on my ascent and start my deco, but the extra stage bottle does add some complexity to operating different parts of one's rig in heavy exposure protection and gloves.

But, as I am doing things this way, I don't see many issues in a couple of years when I get the money to pony up for the full tri-mix course.

PS... I noticed that IANTD's full tri-mix is good to 330 ft. They now have something called an "Exploratory Tri-mix" for an actual "no more C-Card's to earn trimix cert".

 

[grazie42]

I think it was Mike Ferrara who was talking about IANTD technical diver and how it is a deep air course if you dont do recreational/adv. rec trimix first...

My question is:
Why would you want the techdiver cert in the first place?
- I took Technical Wreck Diver & Trimix Diver together (after having done adv. rec. trimix and advanced wreck diver, also taken together with the same instructor). All this seems cosher with regards to IANTD standards, p.79...

If your interest is wrecks, why not go for a combined wreck/trimix course (at the appropriate level according to your backround) and get both for, what I´d guess, is the same money as trimix+techdiver?

Am I missing something?