Abstract: A radio buoy which can be jettisoned from an aircraft by a cable and which is intended to float on the surface of the ocean connected to a submerged hydrophone. During the drop a balloon is inflated by a forced intake of air through holes as a result of articulated openings in the form of scoops, the scoops unlocking by a bar the protective casing of the balloon and the safety device of the container, which is detached after impact with the water, the submerged container being linked with the electronics by a cable. The buoy can be used for underwater monitoring at depths up to 2,000 meters.