When did active underwater sound research begin?

When did work on active underwater sound detection begin?

June 1916 is the date given, following earlier ideas and experiments in detecting submarines.

The date given for the start of active sound-detection work is June 1916. Earlier ideas are placed in 1913, with attempts to find ways of tracking submerged submarines reaching back to 1905. Sound had emerged as a promising method by 1909 in this account. Experiments with bright lights had failed to reveal enough underwater, helping explain the move towards acoustics.