Cheaping out on Trimix - travel gas

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IMO, a lot of the ado about 80% comes from an otherwise long-forgotten history. During the DIR wars, the chief spokesperson for DIR, George Irvine III, published many articles about his beliefs, and he frequently used highly inflammatory language that both excited and enthused his followers and enraged his opponents. Here is a 2013 post from one of his most devoted followers, Dan Volker. In it he quotes one of George's tamer articles explaining why DIR divers never use 80%. If you want to get the tone, skip right to the end.

So, just who is George Irvine III?????

I also suggest you read my response to it, which is in the next post.
Brilliant. Absolutely classic! Little wonder certain people and, let’s say, groups of people have wound their necks back in.
 
I think this is a cultural thing.

however, 50% might seem like a good deco gas unless you are using 32 as back gas and then it’s a bit pointless really. Lots of ways to skin the cat.
 
Thanks a lot to all of you for much valued input.
I've already concluded on not bringing another stage.

I just wanted to point out: Much of the idea behind bringing the additional stage was due to hasselt, as earlier pointed out, 400 liters of Helium isn't very expensive, but those 400 liters may very well be the difference between getting 1 Tx dive compare to 2 TX dives out of a fill, which would help logistically.

I guess the second stage will be trained for at a later point:)
 
If and when you get to staging, you can bring multiple stages of trimix and minimally impact your backgas. In other words, start with the stage, switch to backgas when you empty the stage, then complete your deco. On subsequent dives, start with a stage, or if you're out of stages, then start on the backgas.

The backgas could last multiple dives before you drop below min gas requirements. You also get to dive trimix on all dives rather than dealing with a diluted version. If a dive happened to be within nitrox range, you could even stage with nitrox and barely touch your backgas except on gas switches.

I know that may not meet your objective to save on trimix, but you avoid diluting backgas for your second dive and avoid the validated gas switch. This method would also reduce your LDS visits, as a couple of stages and a set of doubles might last 4 dives, requiring 4 trimix cylinder fills, but could be done in one visit. Doing it your proposed way would still require two doubles trimix fills for 4 dives (4 fills), plus your travel stage fill and the doubles top-off fill after each first dive. That would require an LDS visit after the first two dives to fill the doubles with trimix again.

This trimix stage technique is what I use to help extend the trimix fill in my doubles, otherwise I'd end up having to dump the remainder after two dives. Banked trimix is not an option.

However, if you haven't used more than one deco bottle or stage bottle it is more complicated and needs practice - there's more gas switching, clipping on and off, stowing, and deploying with less space.
 
The way I look at it, 50% is good for the 130-150 range and o2 for anything shallower.
Says the DIR practitioner :wink:
 
If and when you get to staging, you can bring multiple stages of trimix and minimally impact your backgas. In other words, start with the stage, switch to backgas when you empty the stage, then complete your deco. On subsequent dives, start with a stage, or if you're out of stages, then start on the backgas.

The backgas could last multiple dives before you drop below min gas requirements. You also get to dive trimix on all dives rather than dealing with a diluted version. If a dive happened to be within nitrox range, you could even stage with nitrox and barely touch your backgas except on gas switches.

I know that may not meet your objective to save on trimix, but you avoid diluting backgas for your second dive and avoid the validated gas switch. This method would also reduce your LDS visits, as a couple of stages and a set of doubles might last 4 dives, requiring 4 trimix cylinder fills, but could be done in one visit. Doing it your proposed way would still require two doubles trimix fills for 4 dives (4 fills), plus your travel stage fill and the doubles top-off fill after each first dive. That would require an LDS visit after the first two dives to fill the doubles with trimix again.

This trimix stage technique is what I use to help extend the trimix fill in my doubles, otherwise I'd end up having to dump the remainder after two dives. Banked trimix is not an option.

However, if you haven't used more than one deco bottle or stage bottle it is more complicated and needs practice - there's more gas switching, clipping on and off, stowing, and deploying with less space.
Plan A - follow your training and pay the money, deal with the hassle, get two twinsets.
Plan B - invent a convoluted solution such as the one above or your own with whichever “travel” gas
Plan C - get a rebreather.

CCR fixes a bunch of logistical issues. A twinset is brilliant for a lot of diving but if the gas is not easily available it becomes hard.
 
Vive la difference!

All hail the gas boosters!
 
Plan A - follow your training and pay the money, deal with the hassle, get two twinsets.
Plan B - invent a convoluted solution such as the one above or your own with whichever “travel” gas
Plan C - get a rebreather.

CCR fixes a bunch of logistical issues. A twinset is brilliant for a lot of diving but if the gas is not easily available it becomes hard.


Adding stage bottles is really not a convoluted solution at all. It’s far more practical than lugging around two twinsets, and I would argue a rebreather is far more convoluted than doubles and a stage.
 
https://www.shearwater.com/products/peregrine/

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