Metric versus Imperial System for Diving?

[Tigerman]

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That depends on how you approach it. An overnight replacement of everything imperial with metric counterparts would certainly be expensive. It would also be stupid. A slow and steady transition makes much more sense and wouldn't cost a lot. Either way would have prevented wasting $500+ million of tax money due to a mixup of Newtons with pounds...

$500 million is probably a piss in the ocean in this regard though. One thing is all the gauges and wrenches everyone has in their sheds.. Imagine the cost of replacing manufacturing equipment and design processes, cost of reprinting and replacing roadsigns etc..
Hell, 300 million americans replacing two dollars worth of tools exceed $500 million. And then you have the whole issue of "what to do with the discarded stuff" which is both a financial and an economic question.
Yeah, it sure better happen slow or the process would be overwhelming in the first place..

 

[tomfcrist]

You're gonna have to elaborate on that. In what way(s) is the imperial system better than SI? How do the benefits of sticking to imperial units outweigh the benefits of switching to metric?

I don't have to elaborate at all. I for one never said either system is "better" than the other. The contention that because it isn't conforming with the rest of the world America should change to metric, quite frankly is hilarious. America will do what, when and if it wants to to....and doesn't give 2psi about what anyone thinks about it.

Do any US cars still have inch fasteners and fittings? I believe that global companies like Ford and GM are 100% metric now. What US (i.e. non-global) companies are there left?

Yes they still have imperial fittings and parts in the US. Lug nuts come to mind right off the bat...as well as spark plugs.

 

[dfx]

$500 million is probably a piss in the ocean in this regard though. One thing is all the gauges and wrenches everyone has in their sheds.. Imagine the cost of replacing manufacturing equipment and design processes, cost of reprinting and replacing roadsigns etc..
Hell, 300 million americans replacing two dollars worth of tools exceed $500 million. And then you have the whole issue of "what to do with the discarded stuff" which is both a financial and an economic question.
Yeah, it sure better happen slow or the process would be overwhelming in the first place..

Australia's government has spent $15m during the conversion. Their population is a little less than 10% of the USA's population. Be generous and double that estimate and it's still way less than what was lost in the Mars Orbiter.

The cost to the private sector is a different thing but in the big picture I think it would be minimal. Metric is already in wide spread use on a technical level so for most people it would a matter of simply getting used to it. Manufacturing won't go metric over night, which means that whatever is in place stays in place, and when it's time to replace it, replace it with something metric. As for personal uses, you can choose whichever units you like best.

In fact, since SI is a fact that can barely be avoided for many US businesses, there's a certain cost associated with the requirement to work in a dual system even in the private sector, which could be eliminated through complete metrication. Win win.

 

[agilis]

OK, I'm convinced that there appear to be clear benefits to diving metric. So, I guess I will have to replace my 10 +/- imperial SPGs, my 2 imperial IP gauges, my 2 imperial tank pressure checkers, and my 5 imperial only dive computers. I can probably just retire the 6 depth gauges I still have.

Well, maybe I'll wait a while longer.

Don't be in too much of a hurry. Reading through some of the comments in this discussion and trying my humble best to follow the logic produced the expectation that metric depth gauges will soon abandon the measurement of depth in meters and substitute measurement in atmospheres so that they will be consistent with metric pressure gauges. A metric depth gauge would start at "1" for surface or zero depth, but also allowing for less than one for diving at altitude. At about 33 feet sw the depth gauge would show"2", at 66 feet "3", and so on, with lots of little lines on the gauge face to indicate gradations: "1.5", for example, would be the equivalent of 16.5 feet, or 5.03 meters. etc. Just think of the possibilities when atmospheres of compressed gas could in some clever manner be linked to atmospheres of depth. Oh brave new world!

 

[Kevrumbo]

Don't be in too much of a hurry. Reading through some of the comments in this discussion and trying my humble best to follow the logic produced the expectation that metric depth gauges will soon abandon the measurement of depth in meters and substitute measurement in atmospheres so that they will be consistent with metric pressure gauges. A metric depth gauge would start at "1" for surface or zero depth, but also allowing for less than one for diving at altitude. At about 33 feet sw the depth gauge would show"2", at 66 feet "3", and so on, with lots of little lines on the gauge face to indicate gradations: "1.5", for example, would be the equivalent of 16.5 feet, or 5.03 meters. etc. Just think of the possibilities when atmospheres of compressed gas could in some clever manner be linked to atmospheres of depth. Oh brave new world!

What for? As digital depth gauges are now together with double AL80's (the most common single & doubles set cylinders for rent at Dive-ops worldwide), depth in meters also directly translates to bar consumption rate per 10 minutes i.g. 30 meters constant depth for 10 minutes is 30 bar consumed.


Diving the wrecks here in Truk Lagoon for nearly three weeks on double 11L (AL80's), all I need to do is look at my depth in meters and I know how much my SPG reads for every 10 min interval before even looking at it. . .

 

[agilis]

Diving the wrecks here in Truk Lagoon for nearly three weeks on double 11L (AL80's), all I need to do is look at my depth in meters and I know how much my SPG reads for every 10 min interval before even looking at it. . .

Swimming against a strong current or floating effortlessly with that same current makes no difference and will produce the same predictable SPG reading? If all you need to know is depth (in meters, of course) to know in advance what your SPG read will be at 10 minute intervals without reference to changing activity levels or sudden drops or increases in temperature then metric systems are truly amazing. Just time and depth. Almost like diving in a silo.

 

[redacted]

Do any US cars still have inch fasteners and fittings? I believe that global companies like Ford and GM are 100% metric now. What US (i.e. non-global) companies are there left?

US manufacturer cars in then US have SAE nuts & bolts, even when they are assembled in MEX or Canada. Foreign manufacturer cars assembled in the US are metric.

Seems to be a bit mixed with scuba regulators. Most scuba o-rings are SAE; making them inch fraction measures (mostly multiples of 1/16th inch). But a few use metric o-rings for selected applications. It just isn't going away very soon.

 

[Aguablanco1]

It seems that pretty much everyone here agrees that metric is the better system and that it has benefits, even those who still use imperial. Yet nobody (save Kevrumbo perhaps) makes an effort to actually switch. This not only makes no sense, it also makes things more difficult for everybody else.

I will admit that metric is easier. Now what? How does the way in which my gauges show pressure and depth effect the way your gauges show pressure and depth? Are you on a mission to convert everybody in the world to metric? Good luck. Here's a better idea, you do what you want and so will the rest of us. Just because something may be seen as easier doesn't mean everyone is going to do it. Even if you're the one extolling those virtues. I suggest you learn to accept the things you can't change and move on. Or just dive where the metric system is currently in use.
RichH

 

[Kevrumbo]

Swimming against a strong current or floating effortlessly with that same current makes no difference and will produce the same predictable SPG reading? If all you need to know is depth (in meters, of course) to know in advance what your SPG read will be at 10 minute intervals without reference to changing activity levels or sudden drops or increases in temperature then metric systems are truly amazing. Just time and depth. Almost like diving in a silo.

If your SPG indicates 30% or more than your estimate in that 10 min interval, then you're exerting more physically than expected or have a leak somewhere . . . you should simply thumb & abort the dive.

 

[dfx]

Nobody cares that Liberia is using imperial system.

Yet, Liberia is on its way to metrication...