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Captain Hutchinson I. Cone, Commander, United States Naval Aviation Forces, Foreign Service, to Admiral William S. Benson, Chief of Naval Operations


U.S. Naval Aviation Forces, Foreign Service.

4 Place d’Iona,


January 2, 1918.   

From:     Commander,

To:       Chief of Naval Operations, Navy Department, Washington, D. C. (Aviation).

Subject: Hydrophones or C Tubes for use from Seaplanes.

1.   The following is an extract from a Royal Naval Air Service publication of November 7, 1917, on “Methods of Carrying Out Anti-Submarine Patrols.”

Use of hydrophones from seaplanes.

“On July 21st a hydrophone was used for the first time from a seaplane by a 160 H.P. Short machine operating from Dundee. Although a heavy swell was running, the machine landed on the water four miles northeast of Bell Rock. The hydrophone was lowered and the sound of the electric motors was immediately heard, judged to be within a radius of four miles. Listening was continued for five minutes, after which a pigeon message was sent off, and the seaplane returned to base as quickly as possible to report.”

     2.   Information is requested as to the degree of development and success obtained in experiments with hydrophones or C tubes.1 This information is necessary in order that definite recommendations can be made as to whether or not they should be installed on seaplanes operating in Europe.

(SIGNED) H. I. CONE.         

Source Note: TCy, DNA, RG 45, Entry 520, Box 339.

Footnote 1: See: Williams Sims to Office of Naval Operations, 9 January 1918.

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