What is the total number of atmospheres of pressure on a scuba diver standing zero buoyancy in 30 meters / 99 feet of water?

COL Private RallyPoint Member — Thu, 22 Oct 2015 07:16:01 -0400

The total pressure on a diver under water is the result of two separate forces which act simultaneously upon him. These are: the weight of the water and the weight of the atmosphere over the surface of the water. For fellow divers; what is the total number of atmospheres of pressure on a scuba diver standing zero buoyancy within 30 meters of water? Trivia for divers!

Response by LTC Private RallyPoint Member made Oct 22 at 2015 8:19 AM

LTC Private RallyPoint Member — Thu, 22 Oct 2015 08:19:12 -0400

my gut says 1, but would have to dig into the old manuals before I'd wager on it.

Response by SPC David S. made Oct 22 at 2015 9:34 AM

SPC David S. — Thu, 22 Oct 2015 09:34:18 -0400

At sea level its 14.7 x 3 (1 ATA for every 10 meters) + 14.7 (1 ATM for the air above) = 58.8lbs or 4 ATA

Response by Cpl Joshua Wehrman made Oct 22 at 2015 10:20 AM

Cpl Joshua Wehrman — Thu, 22 Oct 2015 10:20:00 -0400

4 ata. 1 atmosphere for every 33ft plus the 1 atmosphere you have from the weight of the air at sea level. I knew this off the top of my head but here is a good cheat sheet

Response by SGT Richard H. made Oct 22 at 2015 12:37 PM

SGT Richard H. — Thu, 22 Oct 2015 12:37:14 -0400

Not really trivia, but a good question that every diver should know.
(Depth/33)+1=ATA
(99/3)+1=4 ATA

Response by SPC Lisa Rudikoff made Oct 22 at 2015 3:53 PM

SPC Lisa Rudikoff — Thu, 22 Oct 2015 15:53:35 -0400

Divide by 33 as every 33' you descend adds one, don't forget one at the surface...so 99/33 + 1...

Response by SSG Bradley Peterson made Dec 15 at 2015 12:32 PM

SSG Bradley Peterson — Tue, 15 Dec 2015 12:32:11 -0500

4 +- depending on the math one does

Response by SSG Bradley Peterson made Dec 15 at 2015 12:41 PM

SSG Bradley Peterson — Tue, 15 Dec 2015 12:41:16 -0500

OK So the obvious follow on would be, What is our best mix? Air NOAA I NOAA II. What is the PPO2 of each mix?

Response by SFC Jonathan Bensman made May 16 at 2016 5:46 PM

SFC Jonathan Bensman — Mon, 16 May 2016 17:46:35 -0400

4 ata

Response by LTC Private RallyPoint Member made Jan 31 at 2019 10:52 PM

LTC Private RallyPoint Member — Thu, 31 Jan 2019 22:52:41 -0500

The buoyancy has nothing to do with it. A diver at a depth of 99 feet in salt water has 4 ata, or roughly 60 psi, pressing on them. In fresh water it would be 3.9 ata, or roughly 58 psi.

Response by SPC Robert Coventry made Feb 28 at 2019 5:02 AM

SPC Robert Coventry — Thu, 28 Feb 2019 05:02:45 -0500

4 I believe

Response by CMSgt Dave Clark made Sep 6 at 2019 10:52 AM

CMSgt Dave Clark — Fri, 06 Sep 2019 10:52:04 -0400

3.983 atmospheres