GSmith
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Looking thru the DIR-F Course workbook uses this term to in the calculation for the "Rock Bottom Calculation." I don't see a definition in the book?
What is ATA?
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"Atmospheres Absolute" or Absolute atmospheres. It is the pressure in atmospheres, including the pressure of the air at the surface.
More specific:
1 ATA = 0 depth (surface) = normal air pressure
2 ATA = 10 meters (33ft) depth = 2X normal air airpressure
3 ATA = 20 meters (66ft) depth = 3X normal air pressure
ETC... notice the pattern?
Note: When doing the pattern from memory it's easy to forget when remembering the values that 1" ATA" is 0 in depth. in other words it is NOT 2ATA/20M/ 2 atmosheres. The depth is always one value LESS than the ATA number. i.e if you are at 60meters you are experiencing 7 atmospheres of pressure.
1 ATA = 0 depth (surface) = normal air pressure
2 ATA = 10 meters (33ft) depth = 2X normal air airpressure
3 ATA = 20 meters (66ft) depth = 3X normal air pressure
ETC... notice the pattern?
Note: When doing the pattern from memory it's easy to forget when remembering the values that 1" ATA" is 0 in depth. in other words it is NOT 2ATA/20M/ 2 atmosheres. The depth is always one value LESS than the ATA number. i.e if you are at 60meters you are experiencing 7 atmospheres of pressure.
Slightly more specific,
As Buccaneer posted, starting at 1, add one atmosphere for each 33 feet you descend in salt water. For fresh water calculations, use 34 feet (freshwater being slightly lighter in weight).
And as Buccaneer points out, Atmosphere Absolute (you may sometimes see ambient instead of absolute, but they mean the same thing) differs from gague pressure in that gague pressure reads zero at the surface (so is off by one atmosphere from ATA).
As Buccaneer posted, starting at 1, add one atmosphere for each 33 feet you descend in salt water. For fresh water calculations, use 34 feet (freshwater being slightly lighter in weight).
And as Buccaneer points out, Atmosphere Absolute (you may sometimes see ambient instead of absolute, but they mean the same thing) differs from gague pressure in that gague pressure reads zero at the surface (so is off by one atmosphere from ATA).
diveman 62
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You should have learned that in your OW certification Class.
If you didn't then your instuctor needs a good talking to.
FPG
If you didn't then your instuctor needs a good talking to.
FPG
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GSmith
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Yup,
We covered that! The shame of it all, he really did do a good job.
We covered that! The shame of it all, he really did do a good job.
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