Could interwar acoustics produce dipping sonar?

Could contemporary acoustic technology support a helicopter-borne dipping detection system?

A crude system is plausible if interwar oceanographic listening work receives focused naval funding, even though it would fall short of postwar dipping sonar.

The scenario begins with interwar oceanographic research, including acoustic work associated with studying underwater volcanoes, rather than assuming that mature postwar sonar appears in 1939. An early system might lower a listening element and a separate sound source instead of matching later integrated dipping sonar. Sustained naval funding for a platform that can use the equipment creates a reason to turn research apparatus into an operational detector. It would remain a primitive detector rather than a fully developed postwar dipping-sonar installation.