reducing trimix costs

[Kevrumbo]

(Destroyer USS Aaron Ward is still on my bucket list, but sadly may not get there any time soon before total collapse of the superstructure).

That 12L stage filled with 18/45 Trimix to 230bar would cost $260 USD in Truk -->Oxygen: $1 per 28 liters, and Helium: $5.75 per 28 liters.

Unless you don't have a DPV/Scooter and expect physical exertion finning hard against a current, or penetrating inside the destroyer at 65m depth where you need Trimix for a clear head -in 28 deg C tropical waters (looking at the YouTube videos), just dive it nice and slow on Air.

For reference, the most bottom time at 60m on a single Alu 11L stage cylinder of Air I ever got was 20 minutes (15 liters/min RMV) on HIJMS Oite Destroyer in Truk.

 

[lermontov]

What Tmx will you be using? How rich a He mix do you need? What deco gasses? Will air be of any use for deco, or will it be an extra bottle to carry, adding complication and risk, not to mention encumbrance? As mentioned above, how much gas will you use on descent and ascent to first deco switch?

Deep diving costs what it costs, and, with all due respect, the sort of planning that you are mentioning indicates to me inexperience and unfamiliarity of the risks associated with multiple bottles and dive planning. KISS is a great review to apply to any procedure.

-Mark

agreed but you dont get experience without at some point starting and as already mentioned im already carrying 3 bottles - not because its necessarily required but because Im training for when it is required. If theres a suitable method that wont overtax me I'll find it. If not Ill adjust or train for it.
Thanks and no disrespect taken

 

[AJ]

good points will need to calculate this and may indeed change things

This concerns me. Did you calculate this dive plan or are you just looking for opinions? Did speak to your buddy about this idea? How well thought trough is this idea?

To be honest, I'am not a Trimix diver yet, but I plan even a 40 meter dive with care. And to be honest, I would rather do these dives on Trimix no matter the cost based on my personal experience at that depth.

 

[DevonDiver]

A stage tank is 'extra' bottom gas. It isn't your sole supply of bottom gas.

This isn't how your were taught to trimix dive (you were taught, right?). And you have nowhere near the necessary experience to start second-guessing the practices and procedures you were taught.

It's no great secret that helium is expensive.

You knew that before you enrolled on the basic trimix course... it was reinforced on the course.... and, no surprises, you're learning it again now you're qualified.

One of the first things tech divers are taught is NOT TO CUT CORNERS.

That's what you're suggesting... cutting a great big corner... because, shock - horror, helium bills are big.

Your suggestion... no redundancy at depth... no gas to share at depth.... it's the antithesis of everything that typifies a prudent, capable technical diver.

Slow down... do some more dives in the air range... you have plenty of experience to still gain in those depths... and save your money to afford the proper use of helium... as you were taught... when you can afford it....and build up your depth experience patiently and progressively.

Tech diving isn't cheap. That's hardly a revelation. Cutting corners and abandoning the very essentials of your training is NOT the answer.

Two factors drive people to cut corners... inexperience and complacency. Recognize that in yourself....and adjust your mindset.

 

[kensuf]

A stage tank is 'extra' bottom gas. It isn't your sole supply of bottom gas.

This isn't how your were taught to trimix dive (you were taught, right?). And you have nowhere near the necessary experience to start second-guessing the practices and procedures you were taught.

It's no great secret that helium is expensive.

You knew that before you enrolled on the basic trimix course... it was reinforced on the course.... and, no surprises, you're learning it again now you're qualified.

One of the first things tech divers are taught is NOT TO CUT CORNERS.

That's what you're suggesting... cutting a great big corner... because, shock - horror, helium bills are big.

Your suggestion... no redundancy at depth... no gas to share at depth.... it's the antithesis of everything that typifies a prudent, capable technical diver.

Slow down... do some more dives in the air range... you have plenty of experience to still gain in those depths... and save your money to afford the proper use of helium... as you were taught... when you can afford it....and build up your depth experience patiently and progressively.

Tech diving isn't cheap. That's hardly a revelation. Cutting corners and abandoning the very essentials of your training is NOT the answer.

Two factors drive people to cut corners... inexperience and complacency. Recognize that in yourself....and adjust your mindset.

^^ this.

 

[northernone]

thanks cameron

yes I appreciate the relative lack of experience and on face value id agree - but to give some extra background I've been a professional mountaineer and problem, solving under pressure is a given to succeed at a professional level. Im reluctant to blow my trumpet but in all honestly I've relished the exactness of technical diving and have found it a pretty easy transition
I did my ADV wreck in 2016 so over a year ago and have since done over 100 or so wreck dives some considerably challenging
bearing in mind the Aaron ward is in tropical warm water with excellent vis ( compared to what im used to)
Just to add more information 99% of my dives over 30m have been no light penetration dives

Ive done my solo dive course and have started an EX-range course that hopefully will be completed soon. Gas planning is of course mandatory and gathering views and ideas is why im posting

there are 6 of us going on the trip (august) my buddy is a very experienced TDI instructor diver with over 7000 dives - in fact we often dive together -knowing how cautious he is is reassuring for me

The plan is to undertake a few dives in the solomons to get all out configurations sorted and assess as we go before taking on the Aaron Ward

I'll make a few more points.

1. I don't doubt your thought processing and problem solving under pressure minset from your profession helps in your learning particularly in the shallow diving you've been doing now. That said, many of us have careers in professions which prepare is mentally for learning and problem solving. (Medics, soldiers, surgeons, pilots etc etc etc) and we know that experience doesn't do us any good to allowing us shortcuts or making us immune to the physiological and physical effects of deep diving.

2. Extended range still doesn't get you anywhere near the depth, taskloading and knowledge needed for a trimix dive.

3. Tdi trimix still only trains you down to 60m and upon completion you STILL won't have the training and certification to safely to plan the dive your currently guessing at taking shortcuts and inventing ways of conducting the dive that don't meet the basic minimum standards to plan such a dive according to the agency you train with.

4. Decompression obligations, gas densities etc don't care how clear the water is. It's way easier to underestimate the dangers in 'safe' looking conditions. A sunny day doesn't make an unexpected rockslide any less risky, so to speak.

5. A few dives, or a few dozen wouldn't prepare for a 64m dive like you describe.

If you're going the TDI training progression and respecting certification limits you are far from being able to plan and execute this dive.

As a side note, with gradual progression, mentorship and EXPERIENCE it could be an air dive but that's not the training route you're pursuing.

Regards,
Cameron

 

[lermontov]

A stage tank is 'extra' bottom gas. It isn't your sole supply of bottom gas.

This isn't how your were taught to trimix dive (you were taught, right?). And you have nowhere near the necessary experience to start second-guessing the practices and procedures you were taught.

It's no great secret that helium is expensive.

You knew that before you enrolled on the basic trimix course... it was reinforced on the course.... and, no surprises, you're learning it again now you're qualified.

One of the first things tech divers are taught is NOT TO CUT CORNERS.

That's what you're suggesting... cutting a great big corner... because, shock - horror, helium bills are big.

Your suggestion... no redundancy at depth... no gas to share at depth.... it's the antithesis of everything that typifies a prudent, capable technical diver.

Slow down... do some more dives in the air range... you have plenty of experience to still gain in those depths... and save your money to afford the proper use of helium... as you were taught... when you can afford it....and build up your depth experience patiently and progressively.

Tech diving isn't cheap. That's hardly a revelation. Cutting corners and abandoning the very essentials of your training is NOT the answer.

Two factors drive people to cut corners... inexperience and complacency. Recognize that in yourself....and adjust your mindset.

all good points and received -thanks

 

[Kevrumbo]

OC Backmount manifolded doubles with Air or 18/45 bottom mix, you're gonna need to handle at least two deco bottles (Eanx50 and O2), and optionally another intermediate deco gas (Eanx36 or Triox 35/25) and/or an additional stage of Air or 18/45 bottom mix, depending on how long of a bottom time you want at 65m.

On OC sidemount then, you will have to "manipulate" at minimum four cylinders: your two bottom mix tanks and two deco gas bottles. Do you have the experience and practice skill to perform this possibly under the narcotic handicap of Deep Air?

 

[TrimixToo]

You don't show the entire dive plan. Have you considered ICD from a switch to air at depth?

 

[lermontov]

OC Backmount manifolded doubles with Air or 18/45 bottom mix, you're gonna need to handle at least two deco bottles (Eanx50 and O2), and optionally another intermediate deco gas (Eanx36 or Triox 35/25) and/or an additional stage of Air or 18/45 bottom mix, depending on how long of a bottom time you want at 65m.

On OC sidemount then, you will have to "manipulate" at minimum four cylinders: your two bottom mix tanks and two deco gas bottles. Do you have the experience and practice skill to perform this possibly under the narcotic handicap of Deep Air?

For 3 yes for 4 not so sure- thats why im heading away to do some practice dives to assess using 4- if it's too much i can adjust my goals or just go to a depth thats within my capability .
@DevonDiver has a good response and as he correctly says no need to rush