Why isn't DIR universally metric?

[AndyNZ]

Much like how most everything in Aviation is in Imperial measures, it could be risky to change over to another system when peoples lives are at risk. Its why it was setup as a worldwide standard. Both activities evolved here in the states, so the majority of the users used imperial measures. When it was, due to a lack of a better term, exported/used more in other countries, the standard continued.

As someone who lived through metrification of an Imperial country, it's actually not that hard or risky.

You start with the Schools, and introduce it over time. The toughest was things like converting people (engineers) from using British Thermal Units to Joules.

I say this somewhat tongue-in-cheek, but the US only adopted Imperial units because of their English heritage... given that the mother country has been going metric since 1842, and full metric since 1971.... well it's about time that the colonies caught up. Oh it would be great if you could start driving on the correct side of the road as well.....

And whilst the US may have had some influence on the evolution of aviation, don't forget that the first powered flight was achieved by a New Zealander... it's just the Wright brothers had better marketing.

 

[Guy Alcala]

You may find it interesting to know that this debate has also been shared within the GUE Instructor ranks. As instructors we are expected to be able to teach classes in both metric or imperial and when travelling we would adapt to whatever is the local "custom". As students, you may occasionaly have metric/imperial mixed teams and in that case the simplest solution is to agree before hand on what units you wish the class taught in and then ensure all students have the same gauges. We have materials available for both classes and will teach in either. I personally find metric easier even though I was on the tail end of the metric changeover in Canada and went through school with imperial. Like some others have posted, divided by ten is dead simple. However I still think miles per gallon and degrees F.....

Good luck in your class! You will enjoy it in imperial or metric.......

Best,

Guy

Guy (this could get confusing fast), since you've discussed it amongst yourselves, was there any strong sentiment as far as whether or why you'd want to keep both (or go metric)? Did any word filter down from the mountaintop (Mt. Sinai, I presume, judging by the reverence some adherents treat such utterances from on high) as to why standardization wasn't being enforced in this instance?

Thanks for the good wishes for the class; it will be a nice change to not feel as if I was ripped off afterwards, as has been my unfortunate experience with too many other diving "classes" I've taken.

Guy

 

[Anti-Hero]

I'm not talking about the US as a whole, just a very small segment of it, DIR divers. The US won't switch to the metric system for everything until sometime after we are no longer the world's largest market and economy, and other countries aren't willing to cater to us because we're no longer the 800 lb. gorilla; instead, there'll be an 800 lb. panda. As it is, most people in the US are perfectly happy to buy their milk by the quart or gallon but their soft drinks in two liter bottles; their food in pounds/ounces but their drugs in milligrams; their gas in (US) gallons, and their tires with width in millimeters but diameter in inches; indeed, they never think about it.

For most practical purposes, there is no compelling reason (yet) for the US to switch entirely from imperial to metric. I will continue to use miles rather than kilometers and feet rather than meters, will retain my tanks with 3/4" -14 NPSM neck threads (but DIN regulator fittings), and don't even think of asking me to cut a pie into 10 pieces; I'll cut it into eight, thank you very much. No, there's no compelling reason to switch, except in cases like gas and depth calculations. Most of us can mentally divide by 10 a lot faster and more accurately than we can by 33.

But the main reason, for the DIR crowd, is sheer consistency. I mean, I've read innumerable lengthy exchanges on such minutiae as what equipment has to go in which pocket, the 'proper' way to clip off, how to mark your tanks, etc., etc. And yet, in the far more significant case of gas planning and calcs, we have two totally different systems in use, and one of them is unquestionably superior to the other _for this specific use_. Where's the logic?

If DIR divers (at least the tech ones) are expected to be able to master calculating MODs, ENDs, EADs, PO2s, ATAs, SACs, RMVs and so on, then switching from imperial to metric for gas planning/depths etc., which both simplifies the calcs and provides exactly the single, universal system that DIR stresses, is easy. Anybody who can master the above can do it.

So, what do US and them funny furrin' DIR divers do when they buddy up, their tanks and SPGs are marked differently, their gas planning numbers are totally different, as are their depth gauges? Let's do a gas check: do you mean 150 bar or 1500PSI? Oh, and negotiating average depth should be all sorts of fun. Nope, no room for confusion or misunderstandings there, because DIR means it's all _standardized_.

IMO the split is indefensible, given the philosophy of DIR. If you're going to drink the Kool-aid, you should be able to mix it in a two-liter container

Guy

The local Monterey DIR contingent has had this very discussion about switching to metric. Not sure if it will happen or not, but if it does, it will likely be done in phases.

 

[Kern]

The 11 liters is irrelevant. The tank is empty.

.

No Walter, the tanks aren't empty, they'r at 1 atmosphere & therefore contain 11lts.

I made the switch from imperial to metric in my late teens. To this day I still visualise length in feet & inches & weight in lbs & stone. When it comes to doing the maths however I'll take metric over things like furlongs, chains, links, rods, poles or perches (which by the way are not universal just as some US weights & liquid measurements aren't really imperial) & barns.

PS. You chaps can't spell litre properly either (or is it just Walter). :mooner:

 

[Blackwood]

The math is the same. To me it makes no difference whatsoever. I can work equally fluently in either of the two major unit systems.

 

[rjack321]

You're right, Lynne, the heck with this whole standardization nonsense. I want to mark my tanks and figure my depth in fathoms (on a logarithmic scale), and have my SPG marked in Torr

On a related subject, now that there are two (three now, I guess) DIR agencies out there, what happens when you get a UTD and a GUE buddy team, and the planned depth of the dive is between 100' and 130'? AIUI, the UTD diver would be planning on using 25/25, the GUE diver either 30/30 or 21/35 depending on the depth. Has this happened to anyone yet? I ask because we've got quite a few trainees of one or the other (or both) agencies who dive in Monterey, and I know many of them have dived together (maybe they just stayed above 100' and avoided the issue).

Guy

Just specify the gas you want to dive not the actual depth which is generally "on the fly" anyway.

Many GUE people outside of FL don't bother with 30/30 which is essentially high flow cave mix. There's another thread here with a poll I started years ago illustrating how little 30/30 is used. And "officially" its MOD is 100ft now just like with 32%, not the old 120ft although many still use it there (ppO2 1.4).

Many GUE T1 divers just use 25/25 cause it makes sense in certain circumstances. And they might use 21/35 for nearly the same depth (but not the same profile) in other circumstances.

UTD T1 is more limited as their card/cert doesn't technically allow 21/35, they need to be UTD T2 to officially get 21/35. Even then I don't envision many UTD divers using 21/35 for a 120ft dive. Since they "grow up" as tech divers using 25/25 its more natural to them whereas GUE doesn't really support an intermediate helium mix to the same extent. GUE has 32% to 100ft in non-strenuous circumstances, 30/30 to 100ft for high flow caves, and 21/35 for 100-150ft dives.

Basically agree on w t f you're doing and its not a problem. If you can't agree on a gas, you might need to rethink how badly you want to buddy up.

 

[rjack321]

Guy (this could get confusing fast), since you've discussed it amongst yourselves, was there any strong sentiment as far as whether or why you'd want to keep both (or go metric)? Did any word filter down from the mountaintop (Mt. Sinai, I presume, judging by the reverence some adherents treat such utterances from on high) as to why standardization wasn't being enforced in this instance?

Thanks for the good wishes for the class; it will be a nice change to not feel as if I was ripped off afterwards, as has been my unfortunate experience with too many other diving "classes" I've taken.

Guy

Because its NOT important what units you use. If JJ tried to "enforce" (how??) the metric system (in the US? lol), many divers -myself included- would just tell the agency to get real.

 

[Kern]

The math is the same. To me it makes no difference whatsoever. I can work equally fluently in either of the two major unit systems.

Thats all very well for people with big brains like you & your friends. People with small brains like my friends & I, just thank heaven they took our LSD away & gave us metric money. Just like you chaps.

 

[nadwidny]

The local Monterey DIR contingent has had this very discussion about switching to metric. Not sure if it will happen or not, but if it does, it will likely be done in phases.

We tried that. It doesn't work. Jump in with both feet or don't bother jumping at all. It just leads to mistakes.

 

[lamont]

In my Cave 1 class, we had one person from Norway and two of us from the States. We traded off leading the dive, and alternated whether we did things in metric or Imperial, so everybody got a chance to do both quite a few times. I certainly didn't find it that difficult (and I now have a conversion table in my wetnotes).

I can't answer why the "powers that be" have not decided to standardize on one system, but I think they probably figure that people intelligent enough to want to dive this way are capable of learning how to do the math both ways

in cave2, i had two buddies in metric and was the lone imperial...

the only real issue was gas planning in the beginning and it fell into a pretty predicable pattern, and a dual bar/psi SPG can fix that problem...