[Date Prev][Date Next]
[Chronological]
[Thread]
[Top]
Re: [PSUBS-MAILIST] New to PSUB (measurement units)
"At 500 feet are how many fathoms ? miles ? inch ? Which pressure psi is
equal to this deep ?
or which water load in pound - and how long takes it for a person, which
use normaly imperial units,
to figure it out ? "
I meant it shouldn't matter what units one decide to design in. But to
answer the question, as I am forced to usually use imperial units as that
is the type of material that is available here, It doesn't take very long
to get a rough answer. depending on how accurate I want, (ball park I use
/2 or 250 psi) It errors on the conservative side and if things are that
close or important then I take the time to do the proper conversion. The
problem stems from the fact that due to where I was born 15000 kg/m3 means
absolutely nothing to me but 250 psi does. I have to further convert the
15000 into psi to be able to digest it. The metric system IS a better
system, however over here it makes more sense to use inches to design some
things in because everything is available in inch sizes. The beauty of the
metric system disappears in some cases if you can't buy 25 mm plate and
must use 25.4mm plate. In this case 1 is a simpler number than 25.4.
I was agreeing with it not mattering:
"On Sunday, October 19, 2003, at 07:09 PM, NeophyteSG@aol.com wrote:
> Agreed. From an engineering calculations standpoint, I prefer using
> metric though conceptually I have to convert it back to inches, feet,
> pounds (or more accurately "slugs"). The numbers and units just
> crunch easier in metric. From a practical standpoint, sometimes you
> just don't have that option.
I used to be a big, gung-ho, advocate of forcing a big switch to SI.
You know: because it just "makes so much more sense" and is "more
scientific." Also because it was more "PC" as in "the rest of the
industrialized world has converted, why won't the US?" It just turned
out to be impractical for me, because here everything is still sold and
described in inches, feet, miles, etc.
I've had a new thought on this, which seems simple and obvious now but
hadn't occurred to me before. And that's that, for people who use math
and measurement all the time, a system of units constitutes almost a
language -- and expecting somebody to change their system just because
"everyone else is using this other one," is equivalent (in a sense) to
insisting that everybody should ditch the language they grew up with,
and switch to Esperanto.
Besides: I read a great line in a science fiction story, about being
distrustful of anybody designing anything important, who would get hung
up trying to divide by 12."
Jay.
MerlinSub@t-online.de
(Carsten Standfuss) To: personal_submersibles@psubs.org
Sent by: cc:
owner-personal_submersible Subject: Re: [PSUBS-MAILIST] New to PSUB (measurement units)
s@psubs.org
22/10/2003 01:43 PM
Please respond to
personal_submersibles
http://www.psubs.org/mlist/archive/0209/msg00033.html
Coalbunny schrieb:
>
> jbarlow@bjservices.ca wrote:
> >
> > I concur 100%. I don't know why it is such an issue. If you want to
call
> > a 36" OD pressure hull 914.4 mm then thats OK. One of my favorite
> > fractions is 5/127. My next favourite is 127/5
> >
> > Jay.
> >
> 25 2/7?
> Carl
>
> --
> "Without deviation from the norm, progress is not possible" - F. Zappa