A Diving Computer Postscript

On reading Calculating a Healthy Ascent in the August issue of Undercurrent, Jim Reilly was prompted to write to us, raising the specter of the likelihood of pressure sensors being inaccurate. He notes that algorithms may be all very well, but if a diving computer reads a wrong depth, it can lead to problems.

Pressure sensor technology has come a long way since diving computers were first mooted. While the original computer, the EDGE, indeed had pressure sensor problems and several divers were bent using it, over two decades of testing numerous computers side-by- side for comparison purposes, I've never found this to be a problem. If a pressure sensor does fail, it's often because the computer has not been rinsed effectively in fresh, clean water after use. Depth sensors can be obstructed by salt crystals. Those who change the batteries themselves can overlook this.

When a dive store changes the battery of a diving computer, they check it afterwards in a test pressure chamber, both to check for leaks and to observe that the computer depth reading conforms to the calibrated depth gauge of the pressure pot. If it does not, the depth sensor might respond to cleaning or it might need replacing.

-- John Bantin