Trimix courses

I've just been reading about the DSAT Tec Trimix Course and its thrown up a
question. A prerequisite to the course is the DSAT Tec Diver cert. which takes
you down to 50m on air. Now, given that the basis of trimix philosophy is to
decrease narcosis and given the fact that air is thus seen as an unsuitable gas
to be used at depth, what is the point in forcing people to have a deep air
certification to be able to enrol in the trimix course which tells you air is -
for lack of a better word - unsafe at that depth?!

I, for example, get narced pretty shallow, around 30m. I would love to be able
to enrol in a trimix course to decrease my narcosis at this depth, but there
aren't any trimix courses available for the type of recreational diving I want
to do. I know trimix is considered to be in the realm of technical diving and
for use deeper than recreational limits, but surely it can still be of
application to divers going to 30m? Why do I have to learn how to go to 50m on
air and be able to do deco diving just to enrol in a course that decreases my
narcosis? I fail to see how trimix and deco are inherently linked. I
understand the argument that it takes concentration and practice, etc to use
trimix, and that as such it may pose a danger to those recreational divers who
become complacent, but wasnt that an argument against the spread of nitrox into
the recreational domain? The other argument I guess would be cost of a fill,
but I know that I for one wouldnt mind paying a bit extra (and taking more time
to prepare pre-dive, etc) to ensure I wasn't narced at 30m.

My question then, is this: I don't want to do deco diving. I don't want to
dive to 50m. I don't want to learn how to manage a twinset. I don't want to
learn how to deploy a DSMB. I don't want to get involved in all those other
aspects of technical diving that trimix courses seem to have integrated into
them. All I want is to be able to use a gas which will decrease my narcosis
within recreation limits, within a no-stop dive and in a single cylinder. Why
isn't there a course for me? I appreciate that having all the technical diving
skills within a trimix course makes it a comprehensive technical course, but
surely there is room for a recreation trimix course, just like there is room
for basic and advanced nitrox courses.

Comments?

Rob F

> My question then, is this: I don't want to do deco diving. I
> don't want to dive to 50m. I don't want to learn how to
> manage a twinset. I don't want to learn how to deploy a
> DSMB. I don't want to get involved in all those other
> aspects of technical diving that trimix courses seem to have
> integrated into them. All I want is to be able to use a gas
> which will decrease my narcosis within recreation limits,
> within a no-stop dive and in a single cylinder. Why isn't
> there a course for me?

There is. GUE Recreational Triox.

Iain

Hi Rob

What about a Nitrox course if you only whant to go down to 30 m and decrease
nitrogen narcosis?

;-> gjw

I see 2 options

1: do the normoxic Trimix
2: Do the tech nitrox depending on your plans

I guess the reason fro the deep air experience is to show you are happy at
depth even if your not narked 50-60 m is still a long way from the surface
and requires a different set of planning techniques and an awareness of the
amount of deco you will rack up and how quickly you start getting into large
amounts of deco. At those depths you have to be aware of how quickly you
will run through a set of twin 12s.

HTH

Frank
"Rob Forey -- The Man With No Nails" <rforey@aol.com> wrote in message
news:20031217195626.14309.00001084@mb-m14.aol.com...
> I've just been reading about the DSAT Tec Trimix Course and its thrown up
a
> question. A prerequisite to the course is the DSAT Tec Diver cert. which
takes
> you down to 50m on air. Now, given that the basis of trimix philosophy is
to
> decrease narcosis and given the fact that air is thus seen as an
unsuitable gas
> to be used at depth, what is the point in forcing people to have a deep
air
> certification to be able to enrol in the trimix course which tells you air
is -
> for lack of a better word - unsafe at that depth?!
>
> I, for example, get narced pretty shallow, around 30m. I would love to be
able
> to enrol in a trimix course to decrease my narcosis at this depth, but
there
> aren't any trimix courses available for the type of recreational diving I
want
> to do. I know trimix is considered to be in the realm of technical diving
and
> for use deeper than recreational limits, but surely it can still be of
> application to divers going to 30m? Why do I have to learn how to go to
50m on
> air and be able to do deco diving just to enrol in a course that decreases
my
> narcosis? I fail to see how trimix and deco are inherently linked. I
> understand the argument that it takes concentration and practice, etc to
use
> trimix, and that as such it may pose a danger to those recreational divers
who
> become complacent, but wasnt that an argument against the spread of nitrox
into
> the recreational domain? The other argument I guess would be cost of a
fill,
> but I know that I for one wouldnt mind paying a bit extra (and taking more
time
> to prepare pre-dive, etc) to ensure I wasn't narced at 30m.
>
> My question then, is this: I don't want to do deco diving. I don't want
to
> dive to 50m. I don't want to learn how to manage a twinset. I don't want
to
> learn how to deploy a DSMB. I don't want to get involved in all those
other
> aspects of technical diving that trimix courses seem to have integrated
into
> them. All I want is to be able to use a gas which will decrease my
narcosis
> within recreation limits, within a no-stop dive and in a single cylinder.
Why
> isn't there a course for me? I appreciate that having all the technical
diving
> skills within a trimix course makes it a comprehensive technical course,
but
> surely there is room for a recreation trimix course, just like there is
room
> for basic and advanced nitrox courses.
>
> Comments?
>
> Rob F

> My question then, is this: I don't want to do deco diving. I don't want to
> dive to 50m. I don't want to learn how to manage a twinset.

Then it is probably not trimix that you want.

> I don't want to learn how to deploy a DSMB.

Humm. Not sure that a sensible thing, but each to their own.

> All I want is to be able to use a gas which will decrease my narcosis
> within recreation limits, within a no-stop dive and in a single cylinder.

I think you may have misunderstood the range of gases available to you. The
gas that decreases narcosis at depths in the recreations range (0-30m) is
not trimix, it is nitrox. A nitrox 35 (35% O2, balance N2) gives a narcotic
depth (END) of 23m at 30m. Perfect for your dive, use a single cylinder and
avoid deco by sticking to (a standard Buhlmann table) of 36mins/30m, no
stop.

> Why
> isn't there a course for me?

For that diving then just take the basic EAN course offered by the likes of
PADI or BSAC. No need to spend TDI/IANTD tmx money.

Cheers
Matt.

"Francis Phillips" <Frank@ccr-frank.co.uk> wrote in message
news:brrqd9$q66$1@hercules.btinternet.com...
> I see 2 options
>
> 1: do the normoxic Trimix
> 2: Do the tech nitrox depending on your plans
>
> I guess the reason fro the deep air experience is to show you are happy at
> depth even if your not narked 50-60 m is still a long way from the surface
> and requires a different set of planning techniques and an awareness of
the
> amount of deco you will rack up and how quickly you start getting into
large
> amounts of deco. At those depths you have to be aware of how quickly you
> will run through a set of twin 12s.
>

I didn't do deep air before trimix (well not more than 45m an not a course)
the new TDI normoxic trimix doesn't require extended range (or so I was lead
to believe) allot is dependent on the instructor.

but its still a 60m qualification which means you have to dive to that depth
on the course and to do that depth you have to have a twinset and stages


if you really are only going to 30m don't bother with trimix - will be more
hassle than its worth
just use nitrox and depth progression

my 2p

"Rob Forey -- The Man With No Nails" <rforey@aol.com> wrote in message
news:20031217195626.14309.00001084@mb-m14.aol.com...
> I've just been reading about the DSAT Tec Trimix Course and its thrown up
a
> question. A prerequisite to the course is the DSAT Tec Diver cert. which
takes
> you down to 50m on air. Now, given that the basis of trimix philosophy is
to
> decrease narcosis and given the fact that air is thus seen as an
unsuitable gas
> to be used at depth, what is the point in forcing people to have a deep
air
> certification to be able to enrol in the trimix course which tells you air
is -
> for lack of a better word - unsafe at that depth?!
>
> I, for example, get narced pretty shallow, around 30m. I would love to be
able
> to enrol in a trimix course to decrease my narcosis at this depth, but
there
> aren't any trimix courses available for the type of recreational diving I
want
> to do. I know trimix is considered to be in the realm of technical diving
and
> for use deeper than recreational limits, but surely it can still be of
> application to divers going to 30m? Why do I have to learn how to go to
50m on
> air and be able to do deco diving just to enrol in a course that decreases
my
> narcosis?

I think that the philosophy behind this is that every agency runs their
courses as a progression of education and therefore knowledge gained during
a previous course will be drawn on. I understand that even normoxoic trimix
requires different planning procedures from nitrox and air.



> My question then, is this: I don't want to do deco diving.

Fine

> I don't want to
> dive to 50m. I don't want to learn how to manage a twinset.

Fine too


> I don't want to
> learn how to deploy a DSMB.

So, you only want to do quarry diving then. Better to be a bit narked to
make it more interesting!


>All I want is to be able to use a gas which will decrease my narcosis
> within recreation limits, within a no-stop dive and in a single cylinder.
Why
> isn't there a course for me?

As others have said, Nitrox.



Keith

gjw wrote:
>
> What about a Nitrox course if you only whant to go down to 30 m and
> decrease nitrogen narcosis?

Well I get just as narked on nitrox as air. At 30m I'm dull, at 40m
I'm silly and I can't tell you what I'm like below that as I just don't
remember it.

20/40 is another matter. You'd be amazed how much better the equipment
behaves on 20/40. Reels reel, cameras take photographs and computers
have sensible, even obvious displays and it's amazing that a bit of
helium can effect a brass piston clip but it does.

You do need some sort of extended range/stop holding skills to do
a helium course because it's a less forgiving gas. It gases on fast
and gases off fast so the tables don't look all that much different
but because of the speed you are dealing with more volume of gas so
if it does go wrong you have much bigger bubbles.

Also deep and fast means that there is very little no-stop time and
even short stops are important. This is why the agencies just don't
run no-stop courses and train for accelerated deco to get you off
the helium on the ascent to get the maximum benefit from the speed.

nigelH

> > The
> >gas that decreases narcosis at depths in the recreations range (0-30m) is
> >not trimix, it is nitrox. A nitrox 35 (35% O2, balance N2) gives a
narcotic
> >depth (END) of 23m at 30m.
>
> This assumes that O2 is not narcotic.

Yes. I think most theories ignore that possibility. It also assumes you
are willing to run a 1.4ppO2 bottom.

> Depending on who else you talk
> to, O2 is at least as narcotic as nitrogen and possible more so.

Possibly. Probably varies from person to person. Personally I do notice a
slight difference with EAN mixes (not that I find it easy to tell).

> There
> may be a placebo effect but I believe that's all.

Then again there may be a real effect. Either way, if it makes you feel
better then it's worth while.

May be O2 is more narcotic for the minority of people who suffer serious
narcosis at depths as shallow as 30m?

Cheers
Matt.

Iain is right. I sat in on a Rec Triox class the other week, and I can
assure you, this is exactly what you want. You will have to demonstrate
proficiency with a DSMB, though

Cheers,

Rich

Iain Smith wrote:

>>My question then, is this: I don't want to do deco diving. I
>>don't want to dive to 50m. I don't want to learn how to
>>manage a twinset. I don't want to learn how to deploy a
>>DSMB. I don't want to get involved in all those other
>>aspects of technical diving that trimix courses seem to have
>>integrated into them. All I want is to be able to use a gas
>>which will decrease my narcosis within recreation limits,
>>within a no-stop dive and in a single cylinder. Why isn't
>>there a course for me?
>>
>
> There is. GUE Recreational Triox.
>
> Iain
>
>
>
>