DIR- Generic DIR Standard Gases Logistics

[jadairiii]

G....I ask because I see a lot of tech-trips and destinations being advertised but when you reach out to them, the boats are often loaded with air compressors and banking O2 for repetitive diving. ....

I cant see how this could happen unless the diver is a complete idiot that didn't bother to ask prior to booking the trip; "got mix?", or the capt/boat are fraudulently advertising mix dives and just ripping people off when they show up and don't have it.

Does any one really just show up to do a tech trip without asking the most basic questions before hand?

 

[Matan]

The real issue is Helium.

Not living in the US basically says sometimes helium supply is limited - i.e. the price per liter is higher.
I can only comment as someone who works at a dive shop (i.e. free O2, compresor, booster, air), and have access to local people with their own compressors/boosters, it's still an issue with OC.

I own my own Helium bank - that's 50L cylinder 200Bar (i.e. 10k liters).
for a tech2 dive if the cylinder's weren't empty (i.e. I have ~60Bar in my doubles, and about 100Bar in my 3rd deco gas), neglecting O2price, I have the following issues:

1. takes forever to boost if He pressure in the bank is low.
2. no one refunds you if you get a new He fill and the bank - so you will boost to the death
3. for O2 again this becomes an issue if low pressure - but low cost.

this means that for a single tech2 dive with std. gasses it takes a lot of filling work if you're doing it all by yourself.
+driving around with your cylinders from place to place.

so actually the issue isn't only financial (He cost) but also logistics - you need to be efficient otherwise it starts frustrating.
the real advantage I see in RB80/CCR is the easier logistics - i.e. you need to fill, but not after every dive. this is a game changer when thinking about backgas fills (it's much easier to throw 2-3 small cylinders and fill, rather than carry a steel twinset). but again this type of thinking is suitable for people who dive regularly (GUE divers for example).


what if I'm stuck and can't make 15/55? I'll live with 15/50 in the worst case - although the majority of times I end up diving 15/60
I will not go with the "dive on air to 45m/150ft" as this is simply not how I want to dive.
if no helium available (example is low availability and price bounced up x2) I'll dive recreational depths.
not saying I like it - but diving properly "gas wise" isn't cheap. than again if one paid for GUE classes, equipment, cylinders etc. , should already know this is a hobby you'll put a lot of money into and get back nothing but joy, salt water, and ultra flex condoms

anyone selling used RB80? - call me

Matan.

 

[CAPTAIN SINBAD]

@CAPTAIN SINBAD would it not be better for them as an agency to come out and correct the information that is taken from their leaders youtube channel to correct any errors? He seemed very clear that RD was how UTD trained their divers.

Either way, what @PfcAJ said is best, figure it out if you believe in why standard gases are used and the benefit that they have for you, or don't dive.

True but in order to learn RD you will first have to learn Buhlmann and Bubble models. RD is taught in addition to that.

 

[Jack Hammer]

Greetings everyone. Id like to know that in your journey as DIR centric divers, how hard has it been to arrange for standard gases at various dive locations? I ask because I see a lot of tech-trips and destinations being advertised but when you reach out to them, the boats are often loaded with air compressors and banking O2 for repetitive diving. If you are TDI or mainstream certified, then you can adjust to the dive with whatever logistics the situation throws at you. If you are GUE or UTD then I would like to know how one would go about it. Any stories or true accounts would be greatly appreciated.

Not as difficult as you might think. Networking goes a long way. So does making a reasonable judgement call based upon what is available and the planned dive/depth or deciding to just not dive (thinking diver).

As for planning... if one's unable to plan the dive and/or make reasonable decisions about the dive, they probably shouldn't be making that dive.

 

[rddvet]

Out of curiosity does anyone have a pdf or excel sheet for mixing standard gases. I have multiple gas blender apps, but I'd prefer to have a sheet I can quickly look at for standard gases showing helium amount and amount of 32%

 

[tbone1004]

Out of curiosity does anyone have a pdf or excel sheet for mixing standard gases. I have multiple gas blender apps, but I'd prefer to have a sheet I can quickly look at for standard gases showing helium amount and amount of 32%

The beauty of the standard gases is that you don't need anything like that. The chart would still be very very big to deal with when you're changing gases and if you're not changing gases, it's really simple math.

Mixing 10/70 to 3600psi of an empty tank, so 70% of 3600psi has to be helium. .7*3600=2500psi which is your helium requirement, balance is EAN32

I have 2000psi of 10/70, and want to know what I'll have if I top off with EAN32 to 3600
2000*.7=1400psi of Helium, balance of EAN32
At 3600psi, 1400 of Helium is 39% and .61*.32 is 19.5% so you'll have 19/40 ish when you top off. Not a standard gas, but it's how standard gases are made.

I have 1600psi of 21/35 and I need to make 10/70 at 3600. 35% of 1800psi is 560psi of He that I already have. I need 2500psi of helium to make 10/70. 2500-560=1940psi of He that I have to add. 1600+1940=3540psi for the final pressure when boosting. After that you can choose to add 60ish psi of EAN32 to balance it out, or just leave it as is and call it close enough.

 

[victorzamora]

Out of curiosity does anyone have a pdf or excel sheet for mixing standard gases. I have multiple gas blender apps, but I'd prefer to have a sheet I can quickly look at for standard gases showing helium amount and amount of 32%

What format are you looking for? As in, what are you hoping it to show? If you know what you want it to show, a table should be easy enough to produce.

As tbone alludes to, above, the math is incredibly simple.​

 

[rddvet]

I'm just lazy and hate thinking about math if I don't have to. A couple of years ago a buddy had a table that I think a GUE instructor made that was a quick easy 2 second glance at the chart to confirm your mix. I appreciate the extra time to show the math. I know the math, but it's nice to see it written out to confirm I'm not too dumb. Mainly I was looking for a quicko, no brain use chart for when I haven't woken up at 7AM and I need to fill some tanks.

 

[tbone1004]

@rddvet better off to buy baltic blender or comparable for your phone, especially for changing mixes

 

[rjack321]

Getting helium isn't that hard, you can even get helium in Chuuk but the price will make your eyes water and curl you up into a fetal position.
There's no scuba police, so I would suggest the following "order"
1) For now, pretty early in your tech diving career, plan to go places where a combination of networking and bulk buying makes helium not so ridiculous, prepare to save your vacation and disposable income to do so.
2) Helium is not as hard to get as the internet (especially SB) would have you believe. People like to cite places like Chuuk where its ridiculously expensive - but their motives are mostly to rationalize why they are diving deep air in places like south FL where its probably the cheapest of all. Build your network of sources and mostly just know who to ask. Locals who know can get He.
3) Plan shallower dives or shallower destinations, nobody you care about is going to call you a wimp for saying "we kept it all to <110ft cause we didn't have access to helium" (the macho dudes will call you a wimp, let them, its the best way to find out who you never want to dive with)
4) Dive a high helium mix you brought from home then blend it down to a weaker helium mix for a second dive if you have to, 21/20 at 150ft isn't ideal but its not clearly insane. This is a slippery slope that only you can judge.
5) Get more OC training to the point where it makes sense that you could transition to a CCR. The people that say you should go to CCR sooner because you will "do that eventually" are the same drama llamas that think its a big deal to do an OC bailout from 250ft (it should be casual and easy - cause you have done OC dives/ascents from 250ft)