Two types of under-water quartz transducers, namely, the mosaic type & the array type, were designed and manufactured, particularly paying attention to the points of cementing of crystals and supporting of vibrating bodies, with a view to reducing the equivalent resistance r of the transducers when they are unloaded. A transducer of the mosaic type with an area of 609 mm2, unsupported, measured 60 k Ω for its r, while one of the array type with an area of 259 mm2, 15 k Ω. Finally, discussions were made on the comparison of these two types of transducers with the conclusion that a transducer of the array type possesses more merits than that of the mosaic type. The ways for further improvements were considered.