triox vs. trimix?

[Brian of Aquanauts]

Originally Posted by weazelz

oh purrrlease. you're going to quibble over an END of 31.25m when you dive EANx32 to 30m? & sub-1.4ppO2 is just fine by any tech agency except GUE

yes i am... but i'm not trying to tell people that my way is any better. We each have to choose what risks we are willing to take for ourselves, my choices are mine and i'm just explaining the way that i make them.

You can either take that on board or just read for interest, but you can't tell me that i don't have reasons for my actions. And there's nothing wrong in me trying to educate about why i do things a particular way after all, knowledge is power.


EDIT and you never answered my question... would you really PLAN to stay in the water for nearly double your total runtime for a lost deco gas?

[weazelz]

Originally Posted by Brian of Aquanauts

EDIT and you never answered my question... would you really PLAN to stay in the water for nearly double your total runtime for a lost deco gas?

I think you asked Si that, but I'll answer anyway...

per my caveat earlier, I'm not trimix trained, but that's the way it's taught at AN/DP level. I reckon it would be a 61 minute runtime with 50% deco, & 91 minute for lost deco gas, so half as long again, but not double

[Brian of Aquanauts]

It's a pity you were only taught one solution to that problem.

It makes for a good debate, and gives a good range of problem solving skills if you can have lots of alternatives for problems like a lost deco gas.

Skills that are worth knowing, and often discussed on a GUE Tech courses:
Lost deco gas, share team members gas V back gas solutions
Altering deco profiles / the Oxygen Window
Addition of deeper stops / ascent rate variation
Use of bubble models vs buhlmann
Emergency ascents, re-decents
Use of support divers
Emergency protocols
What deco you really need to do to avoid a fast tissue bend in an emergency

The GUE Tech 1 course is like a combined Advanced Nitrox, deco Procedures, Normoxic Trimix and Advanced Line Laying, so goes into things in quite some depth. Maybe you can get your Trimix instructor to cover some of the above.

[weazelz]

Originally Posted by Brian of Aquanauts

The GUE Tech 1 course is like a combined Advanced Nitrox, deco Procedures, Normoxic Trimix and Advanced Line Laying, so goes into things in quite some depth. Maybe you can get your Trimix instructor to cover some of the above.

I will ask, he's quite good

[big_si]

Think a lot of that should have been covered in the AN & DP course with 'your instructor' ... I guess some of the level of detail may depend on questions asked though?

I can certainly remember covering the bits below in bold below

Originally Posted by Brian of Aquanauts

Skills that are worth knowing, and often discussed on a GUE Tech courses:
Lost deco gas, share team members gas V back gas solutions (yep)
Altering deco profiles / the Oxygen Window (yep)
Addition of deeper stops / ascent rate variation (yep)
Use of bubble models vs buhlmann (yep)
Emergency ascents, re-decents (yep, missed stop protocols)
Use of support divers (yep)
Emergency protocols (missed stop protocols, team solutions to problems)
What deco you really need to do to avoid a fast tissue bend in an emergency.... (Maybe?? My lost deco gas plan would be run at minimal conservativeness)

The GUE Tech 1 course is like a combined Advanced Nitrox, deco Procedures, Normoxic Trimix and Advanced Line Laying (TDI adv. Wreck more, but some covered at AN+DP), so goes into things in quite some depth. Maybe you can get your Trimix instructor to cover some of the above.

Tech 1 sounds like a very thorough course!! Lots to cover indepth in one course!

[IanDennis]

Sorry I come to this a little late in the thread-been on a train.

As somebody who is actively teaching triox courses via IANTD's Advanced recreational course, I am seeing many more divers become interested in having some helium in the mix to reduce levels of narcosis.

Triox is hyperoxic trimix- i.e the o2 percentage is higher than 21%. For IANTD triox then mixtures must contain at least 24% 02 and can range from 32/15 for 30m dives to 25/30 for 45m dives and should have an EAD of no greather than 24m. For a 45m dive then 25/30 would give you an EAD of 21m and a quite acceptable P02 of 1.34 for your target operating depth. For contigencies the mix is acceptable down to 48m - 23m ead and 1.41.

The triox course is designed around divers making the transition from recreational sport diving to taking their first steps on the technical ladder. Limitations for the course are a maximum depth of 48m and a maximum mandatory decompression stop obligation of 15 minutes. Decompression gases maybe upto 100% 02 but personally I would consider 50% to be a more appropriate gas for 40m dives as it provides many more options than trying to use 100% and you can get on it at 21m if required.

From a diver prespective if they were considering doing Advanced Nitrox then I would seriously look at Triox as a viable alternative for diving in the 30-45m zone. The course structure is identical and covers the same skills- kit configuration, propulsion methods, shutdowns, oog, dsmb use, use of a stage and stage handling, deco procedures, emergency procedures etc.

Divers who qualify with Triox have the advantage that they can choose to use either Triox or a weak nitrox mix for their diving. Some divers might reflect that 15minutes of deco is a disadvantage against unlimited deco- bear in mind that the course is aimed at developing the diver and that you need to walk before you can run

I think that the majority of divers would agree that in this range Triox has many advantages of nitrox mixes in terms of levels of narcosis. Whilst Triox does require students to be able to control ascent rates and carry out decompression stops then this is no more onerous that carrying out similar stops on Nitrox.

As intermediate training prior to moving onto trimix then I would recommend the course as the core skills required give an excellent foundation for more advanced training. The course also encourages the divers to think as a team and look at team solutions to problems that might occur underwater- as Brian says there are a number of different options open to you .

Andy - if you want to see how the course works them pm me- always got a need for good safety divers --though you would need a trimix or triox cert .

HTH

Ian

[Garf]

Originally Posted by big_si

Think a lot of that should have been covered in the AN & DP course with 'your instructor' ... I guess some of the level of detail may depend on questions asked though?

I can certainly remember covering the bits below in bold below



Tech 1 sounds like a very thorough course!! Lots to cover indepth in one course!

It's a bloody superb course. There is a lot to cover. When we did it we were on the go from 7am until about midnight for five days, then we did about 25 training sessions to get up to pace,m and then did another two days of it. Well worht it though

[big_si]

Originally Posted by Garf

It's a bloody superb course. Tech2, on the other hand, is looking a bit hard

Sounds like fun! What on earth does Tech 2 cover?? (Sorry for the aside Andy!)

[Garf]

Originally Posted by big_si

Sounds like fun! What on earth does Tech 2 cover?? (Sorry for the aside Andy!)

Course Limits


General Training Limits as outlined in Section 1.4
Student to instructor ratio is not to exceed 3:1 during any in-water training
Maximum depth 240 feet (+/- 10 feet)/70 meters (+/- 3 meters)
No overhead environment diving (excepting decompression)

Course Content


The GUE Tech 2 course is normally conducted over a 5-day period, and cumulatively involves a minimum of forty (40) hours of instruction, designed to instill in divers a working knowledge of extended range diving; including physiology, tables and logistics. Special emphasis is placed on extended exposures and on their associated considerations (gas consumption, DCS, Oxygen toxicity, and thermal concerns).

Academic Topics


GUE organization
Limits of training
Course completion requirements
Review of decompression, gas utilization and risk, diving physiology
Accelerated, omitted, and general decompression strategies
Dive logistics and planning

Land Drills & Topics


Spool, reel, and guideline use
Dive team order and protocols
Gas switching procedures and protocols
Bottom, stage, and decompression bottle use

Required Dive Skills & Drills


All skills and drills as outlined in General Diving Skills, Section 1.5.
Review procedures for gas failures; including valve manipulation, gas-sharing, and regulator switching (as appropriate).
Effectively and comfortably demonstrate the ability to deploy a lift bag/surface marker buoy in less than two minutes while hovering stationary. Participants should not vary in depth more than 5 feet/1.5 meters.
Demonstrate the clean and effective removal and exchange of multiple stages and decompression bottles while hovering horizontal. The participant must be capable of removing and replacing each of at least two bottles in less than one minute, i.e. one minute per bottle.
Be able to comfortably demonstrate at least two propulsion techniques appropriate for delicate and/or silty environments.
Equipment familiarization.
Gas-sharing scenarios to include gas-sharing for at least 200 feet/60 meters.
Demonstrate the effective deployment of a reserve light in less than 30 seconds.
Demonstrate excellent buoyancy control skills, including when conducting stage and decompression gas switches.
Demonstrate effective valve-management.

[big_si]

Originally Posted by Garf

Meh meh meh... tech 2.... meh meh meh... easy stuff... meh meh meh...

Piece of piss!


Good luck with that!