Living at Altitude Diving at Sea Level

Saudi-Diver · Sep 7, 2003

Hi we are a group of British and American Expats who live and work in Saudi Arabia in a Place called Khamis Mushayt, its at 6700 ft above Sea level. At the weekends a lot of us go diving at the Red Sea which is a two and a half drive away. Me and my friends use the "No fly" facility on our computers to determine when we can go back up the hill. This limits our depth and duration of dive as we aim to arrive at the steep bit of the climb with zero no fly time. Is this too cautious as lots of people dont bother with the no fly time because

A. The ascent is gradual

B. No fly is precautionary just in case the Aircraft has a cabin decompressurisation.

I am a little sick of being called a wuss. Ive also seen no adverse symptoms in people that have driven up the hill with over 12 hours no fly.

Can anyone help.

ABQdiver · Sep 7, 2003

Although it's not as much differential as your situation, to err on cautions side would not be a bad thing. Think of the consequences!

Our local dive spot is at 4680' and we all wait until we're C group divers (or pretty close) before heading out to go over the high spot on the way back to Albuquerque at 7800'.

It's your body, treat it as you see fit.

Check out this for some info, might help you.
http://www.ndc.noaa.gov/pdfs/AscentToAltitudeTable.pdf

boydski · Sep 7, 2003

Stick with your No-fly limit and ignore the "wuss" comments. I personally know 3 different people that have had DCS hits after doing very moderate dives and then ascending into the mountains a few hours later. One of these poor individuals has permanent nerve damage that forces her to walk with a pronounced limp.

All 3 cases involved a pair of rather short, shallow dives ( 1 in cold water, 2 in warm water ) and then an ascent to go through a mountain pass a few hours later. The pass elevations were all much lower than the elevation that you live at and the effects from the DCS hits started appearing at about 4000'. In 2 of the cases, the symptoms were very severe, and involved a lengthly air evactuation, and several trips to a chamber.

I would play it safe, and stay as long as you can.

itziar · Sep 7, 2003

Hi Saudi-Diver,

I also live at altitude (2200m, ~7300ft?) in Central Mexico, and stick to the no-flying rule when going to dive to the Gulf, a 3hr drive away from home. The dive shops here recommend waiting for 18hr after the last dive, so we normaly stay one extra night after our Sunday dives, and head home early Monday morning. I have seen many other divers heading home immediately after finishing their Sunday dives, claiming that they always have done so, and nothing has happened to them, but I would not venture it. Aircrafts are pressurized to the equivalent height of 2000-3000m, after all!

Stay safe,

Itziar

DandyDon · Sep 7, 2003

Saudi-Diver once bubbled...
B. No fly is precautionary just in case the Aircraft has a cabin decompressurisation.

I believe the Wait Before Flying rule is because cabins are pressurized to 8,000 ft equivalent, whatever the pounds per sqaure inch of pressure are?

Call Divers Alert Network, maybe, but I think they'll suggest a 12 hour minimum, 18 after multiple dives. I'd go for the 18 hours, even if I had to take an additional car and follow later.

Sorry I can't talk in metric, but like many Americans, I don't know what feet, pounds, inches, hours are in metric. :dunce:

DON

SubMariner · Sep 7, 2003

Saudi-Diver you are right to use the "Flying After Diving" rule to guide you when returning to your "home altitude" after diving.

DCI doesn't care whether you are flying in a plane, or ascending to altitude in a car; the physics & physiological aspects are the same.

DSDO,

~SubMariner~

cnidae · Sep 8, 2003

boydski once bubbled...
I personally know 3 different people that have had DCS hits after doing very moderate dives and then ascending into the mountains a few hours later. The pass elevations were all much lower than the elevation that you live at and the effects from the DCS hits started appearing at about 4000'.

Come on. These guys did'nt get bent from the alttitude, they were already bent when they came out of the water. 4000' is the same pressure as 4 feet in sea water.

DeepTechScuba · Sep 8, 2003

Gentlemen, if you do not have access to a NOAA DIVING MANUAL then send me privately your fax number and I will fax you a copy of the NOAA re-ascent to altitude tables. It is a one page table that answers your question as to how long you must wait at lower altitude before you can return to XXXX ft.

vicky · Sep 8, 2003

I posted a few weeks ago a link from a Jordanian decompression study of several cases, where people have been diving in Aqaba and got DCS while driving back home to Amman. I don't remember in which thread it was but I think you can search for "decompression and driving" and the forum's search engine should nail it for you.

jbichsel · Sep 8, 2003

cnidae once bubbled...

Come on. These guys did'nt get bent from the alttitude, they were already bent when they came out of the water. 4000' is the same pressure as 4 feet in sea water.

Am I missing something here?

I was alway taught that as you ascend in elevation the pressure decreases, not increases.

To say that "4000' is the same pressure as 4 feet in sea water", kind of upsets the whole nature of physics, eh?

Maybe I'm not understanding.

Living at Altitude Diving at Sea Level

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