Which mixes for trimix are better for 330 feet (100 meters)?

[bigken462]

As a reminder here, we should not interfere with natural selection!

Kenny

 

[nereas]

As a reminder here, we should not interfere with natural selection!

Kenny

Well he did ask, and even though he seems to be in over his head, a bright mind will normally figure things out eventually. A bright mind is worth saving.

 

[Mike Edmonston]

Ugh......

In the interest of education and perhaps saving a bright mind.

ASSUMING you are diving between 300' to 330'

Bottom gas - 10/70

Travel gas/first deco gas - 30/40
This mix will minimize ICD

100% O2 for final Deco. (20' and above)

You don't want to spike your nitrogen, hense the 30/40.

You can hang an extra bottle of 30/40 on the line if you want redundant bailout.

DISCLAIMER: I am not telling you how to do this dive, I am only explaining which gasses you COULD use for this dive. Discuss your choices with your team / instructor, before attempting this dive.

Have a nice day.

 

[bigken462]

Lol, I guess you're right. As a Paramedic, we often see folks just begging for a killing. We call these folks "volunteers" Grrrrr, I suppose I should have told the feller it would be a good idea to ask for a refund of his dive instruction, or perhaps in this case......Annie up and pay for some.

I'm not a Trimix diver yet, so I can't, nor would I comment on how to tell this feller how to go about diving his plan, however that said, I would never disgrace my past instructor by posting silly questions like this on Scuba Board. Now on the other hand, if the feller is just curious on what it takes to do a dive like this out of general dive chat, I guess there is no harm in asking. I suppose at some point in time, someone asked what it would take to go to the moon.


Kenny

 

[Blackwood]

Blackwood, if your back-gas on your 150 ft dive is nitrox, then fine, only one bottle of EAN 50, as long as there is enough nitrox (EAN 25) in your twins to deco completely on, should the EAN 50 bottle fail. It would sure be a long deco period.

Backgas deco normally either takes a really long time, and is miserable, or else is not feasible at all, when the backgas is trimix.

Those who teach backgas deco as a backup have often not even considered how much deco time that would take.

Of course they consider it! In fact, they consider it exactly. Otherwise, they would be unable to teach how to handle a lost deco gas.

And I don't see how you got confused on my previous post, regarding EAN 50.

Probably because it was a small discussion you and I had with respect to this post:

Carrying a single bottle of 100% O2 is probably not a very good idea.

When I carry a single bottle, like this, it normally has EAN 50 in it. And then, I am normally wearing my twin tanks, as well.

Makes it seem like you dive with one deco gas regularly enough to necessitate the qualification 'normally'.

Note, the gist I got from that discourse is that you feel oxygen is a dangerous deco gas, which would raise questions about the wisdom of using oxygen as redundancy for 50%. But I may have misinterpreted your intent.

 

[amascuba]

Those who teach backgas deco as a backup have often not even considered how much deco time that would take. For anyone seriously considering doing that, I would suggest hanging a spare deco bottle from the boat, as well.

That's part of the dive planning process. As part of a contigency you figure out how much back gas it would take to complete the dive with out a deco gas. I did it in my class. You didn't do it in yours?

 

[texdiveguy]

That's part of the dive planning process. As part of a contigency you figure out how much back gas it would take to complete the dive with out a deco gas. I did it in my class. You didn't do it in yours?

This thread is concerning a 330ft. trimix dive.......were would a hypoxic back gas figure into a contingency if all deco gas/s were lost?

 

[ucfdiver]

This thread is concerning a 330ft. trimix dive.......were would a hypoxic back gas figure into a contingency if all deco gas/s were lost?

I think it spun off me correcting that one deco gas is *NEVER* enough, as earlier in the thread it was stated out of the context of a 300ft dive. Even without trimix training, I can figure out the obvious dangers using backgas to deco out on a 300+ft dive. Sorry for the confusion that caused.

 

[texdiveguy]

I think it spun off me correcting that one deco gas is *NEVER* enough, as earlier in the thread it was stated out of the context of a 300ft dive. Even without trimix training, I can figure out the obvious dangers using backgas to deco out on a 300+ft dive. Sorry for the confusion that caused.

Hey no problem.....I did not read through all the posts again to see....thanks for the explanation.

 

[amascuba]

This thread is concerning a 330ft. trimix dive.......were would a hypoxic back gas figure into a contingency if all deco gas/s were lost?

Don't get me lying. I obviously haven't been trained in the uses of hypoxic mixes. There would be concerns of breathing hypoxic mixes above a certain depth as well as the logistical night mare of carrying that much back gas. I could probably think up a plan, but you wouldn't catch me diving it at my current level.