This article is about underwater sound propagation. 1490: a tube inserted into the water was said to be used to detect vessels by placing an ear to the tube. Submarine Signal Company in Boston, built an experimental system beginning in 1912, a system later tested in Boston Harbor, and finally in 1914 from difference between sensor and transducer pdf U. 1915 were equipped with a Fessenden oscillator.
Russian immigrant electrical engineer Constantin Chilowsky, worked on the development of active sound devices for detecting submarines in 1915. This work, for the Anti-Submarine Division of the British Naval Staff, was undertaken in utmost secrecy, and used quartz piezoelectric crystals to produce the world’s first practical underwater active sound detection apparatus. 1920 and started production in 1922. The 6th Destroyer Flotilla had ASDIC-equipped vessels in 1923. Sonar QB set arrived in 1931. This required an attacking vessel to pass over a submerged contact before dropping charges over the stern, resulting in a loss of ASDIC contact in the moments leading up to attack.
The hunter was effectively firing blind, during which time a submarine commander could take evasive action. Developments during the war resulted in British ASDIC sets that used several different shapes of beam, continuously covering blind spots. Research on ASDIC and underwater sound was expanded in the UK and in the US. Many new types of military sound detection were developed. At the end of World War II, this German work was assimilated by Britain and the U. In recent years the major military development has been the increasing interest in low-frequency active sonar.