Examples from the Web for hydrophone
The development of the hydrophone for anti-submarine work, both from ships and from shore stations.The Crisis of the Naval War|John Rushworth Jellicoe
Then came the store rooms and wireless and hydrophone rooms.The Thick of the Fray at Zeebrugge|Percy F. Westerman
The "water noises" were reduced and, greatest improvement of all, the hydrophone was made "directional."
The simple movement of a vessel's hull through the water cannot be heard on a hydrophone.
The Adriatic Sea was an ideal place for the use of the hydrophone.Inventions of the Great War|A. Russell (Alexander Russell) Bond