Some Acoustic Properties of Marine Fouling

The fouling of transducers by marine organisms imposes a handicap on the use of underwater-sound equipment, especially in low latitudes. Sensitivity and sound-emitting power are reduced. In order properly to plan countermeasures, quantitative data on the effect that fouling organisms have on the reflection and absorption of sound have been accumulated by measuring a series of test panels which had been exposed to fouling in Florida waters. The test panels were measured periodically, at a frequency of 24 kc. The extent of absorption caused by fouling can reach a magnitude of 3 decibels per inch of thickness. Distortion of transducer patterns is another effect of the fouling. Antifouling methods are described. The acoustic attenuation of certain antifouling paints are found to be negligible.