AUDIOGAUGE SURVEYS
An audiogauge is an electronic device used to measure the thickness of metal or other homogenous materials. The audiogauge works by means of injecting a sound wave of a specific frequency into one side of the piece to be measured, and determining length of time it takes the signal to bounce back off the other side. The unit is adjustable for the different sound wave transmission characteristics of different materials, such as steel and aluminum. Once properly set and calibrated, the audiogauge can give a very accurate readout of the thickness.
The most common use is to determine the overall thickness of metal hulls, decks or bulkheads, thereby establishing the degree of loss, if any, due to corrosion. Since the probe is of small size, roughly the size of a nickel, an audiogauge is not as useful in trying to detect localized corrosion, such as pitting, since the probe would have to be placed directly over a hidden defect in order to detect it.
Use of an audiogauge requires a trained operator, since there are certain conditions which require interpretation of the results of the test.