ATA vs ATM which is right? Need to know for magazine.

[paperdesk]

Oh no roak, it's just evil to bring that into it

300bar: Wow, I didn't know that the Dutch were such prolific divers! Pretty cool.

 

[300bar]

300bar: Wow, I didn't know that the Dutch were such prolific divers! Pretty cool.

Just come on over,and we'll show you.
Dont know IF you speak or read any Dutch,but just click the link and read the # in the 2nd line.
http://www.natuurlijkoostvoornsemeer.nl/?fId=18
Just have a look at the(round)pics on the right.

 

[Charlie99]

Of course 1 BAR does not equal 1 ATM, adding to the confusion.

Roak

Further adding to the confusion, 10msw (meters saltwater) is usually defined to be equal to 1 bar, not to 1atm. While this means that bar to msw conversion is just moving a decimal point, 10msw is NOT exactly equal to 33 fsw (They differ by 1.325% since 1atm is 1013.25 millibar, not 1000 millibar)

 

[300bar]

(They differ by 1.325% since 1atm is 1013.25 millibar, not 1000 millibar)

As I said not interesting for scuba uses.

 

[paperdesk]

As I said not interesting for scuba uses.

It's a little bit interesting to me, but I work in feet and lbs and now ata anyway . . .

300bar, As far as I know none of my South African (Afrikans) or Dutch family dive. Soo sad. I see your sig says Evert. Is that your given name? That's my family name! Not Everett, or Everet as most Americans want to spell it.

Ted

 

[300bar]

It's a little bit interesting to me, but I work in feet and lbs and now ata anyway . . .

300bar, As far as I know none of my South African (Afrikans) or Dutch family dive. Soo sad. I see your sig says Evert. Is that your given name? That's my family name! Not Everett, or Everet as most Americans want to spell it.

Ted

Ted,

That is my given/first/christian name.So sorry no family.
As for the Americans,most can't even spell my name correct in a PM.
It's Evret or Evart or Everett and then some more.
Most call me ED when we meat.
btw we had/have some family in South Africa somewhere around Cape Town.

Evert.

 

[roakey]

Scientificly you're correct,but for scuba the difference is so small we can ignore it.

In the case we're talking about, yes. But when we start talking about cylinder pressures, it adds up. So I prefer not to muddy the waters to begin with (google "The Law of Primacy" as it relates to education).

Roak

Ps. Personally, I want a depth gauge that reads in atmospheres (or BAR, since for depth as you mention it does't matter) so I can drop all the depth conversions!

 

[Charlie99]

Ps. Personally, I want a depth gauge that reads in atmospheres (or BAR, since for depth as you mention it does't matter) so I can drop all the depth conversions!

Depth in meters comes pretty darn close to being depth in bar --- just drop a decimal place. It's a lot easier to just drop a decimal place than is is to divide by 33.

BTW, the easy way to divide by 33 is to multiply by 3, and then drop 2 decimal places.

For example, 50' x 3 =150. Divide by 10 to get 15 meters, divide by another 10 to get = approx. 1.5atm ....... or 2.5ata or 2.5bar absolute.

 

[paperdesk]

Depth in meters comes pretty darn close to being depth in bar --- just drop a decimal place. It's a lot easier to just drop a decimal place than is is to divide by 33.

BTW, the easy way to divide by 33 is to multiply by 3, and then drop 2 decimal places.

For example, 50' x 3 =150. Divide by 10 to get 15 meters, divide by another 10 to get = approx. 1.5atm ....... or 2.5ata or 2.5bar absolute.

I'm intrigued by all this. Being strictly a recreational diver, and not having even taken a Nitrox course I haven't really thought about things in this light. It's all very interesting though! Thanks for sharing.

Ted