Abstract: An expendable oceanography probe has a hollow cylindrical housing, a front end element in the form of a weight fitted into the lower end of the cylindrical housing, a sensor, such as a thermistor, mounted on the external surface of the front end element for detecting information relating to the water to be tested, an oscillating circuit the electrical signals of which are changed according to the signal from the thermistor, an electroacoustical disk transducer combined with the oscillating circuit for radiating a sound signal into the water corresponding to the detected temperature of the water, a transducer holder fitted on the upper end of the cylindrical housing and a rear end disk plate on the transducer holder. A center axle, a cylindrical side wall and an end surface of the transducer holder form a cavity for radiating the sound signal. The transducer has a center hole, and it is mounted on the external of the transducer holder on the center axle and is held thereon by the rear end disk plate.