November 2011    Download the Entire Issue (PDF)

Vol. 26, No. 11   What's this?

Which Dive Computers for High Altitude Diving?

from the November, 2011 issue of Undercurrent  

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Most diving is obviously done at sea level but there are some freshwater divers who go to lakes in the Sierra Nevadas, the Rocky Mountains and other places 2,500 feet and higher. If they're relying on the dive computers they use while diving at sea level, they may not be getting the correct readings for decompression levels.

"Depth estimation will be affected, and at high altitude, a diver will need to dive deeper in the water column to achieve the same depth reading as at sea level," says Martin Sayer, editor of the journal Underwater Technology. "This effect will be amplified in freshwater if the dive computer pressure sensor is calibrated to brackish or full seawater. Altitude has an obvious effect when the diver surfaces and continues to off-gas at much different pressure gradients to those expected at sea level."...