Installation under floating beacons and beacons of the bells shipped in water was the earliest use of an underwater sound. In the period of poor visibility the sound of these bells could be found at long distances by means of the hydrophones installed in the vessel case.
profilings by method of the reflected waves that allowed to study character of the structures and formations lying under a surface of an oceanic bottom. This method investigated many continental slopes on the globe; uncountable profiles crossed all oceans that provided receipt of a huge flow of information.
The centuries-old history of human society, all its way to progress are closely connected with the ocean — with navigation, with development its huge food, raw, and later and fuel and energy resources. "Soon with the Ocean, perhaps, the problem of the existence of mankind will be connected," — the famous researcher of sea depths Jacques-Yves Cousteau claimed.