HAYES— U. S. NAVY MV TYPE OF HYDROPHONE. 373 



lem of transporting our troops back again arose it was suggested 

 that this device, if installed on transports, might prove to be of 

 value in safeguarding the lives of these men during fog or other 

 conditions of low visibility. This suggestion was strongly backed 

 by Rear Admiral B. C. Decker, U.S.N., then Senior Member of the 

 Special Board on Anti-Submarine Devices, and by Captain J. R. 

 Defrees, U.S.N., Secretary of the Board, and led to the equipping 

 of the U. S. S. Von Steuben with an electrical MV hydrophone for 

 the purpose of ascertaining whether or not such a device could effec- 

 tively serve as an aid and safeguard to navigation. 



Experimental Results Obtained on the U. S. S. Von Steuben. 



The writer was fortunate in having charge of the hydrophone 

 installation on the Von Steuben during the first trip from Hoboken 

 to Brest and return, a trip which in his opinion will come to be re- 

 garded as epoch-making in the annals of navigation. 



The Von Steuben proceeded at one third speed while leaving New- 

 York harbor. During this period neighboring tugboats and ferries 

 were readily located by determining the direction of their propeller 

 sounds. Arrangements had been made to have the lightships along 

 the approach to New York harbor sound their submarine bells and 

 the signals from all these lightships (Ambrose, Fire Island, Cardinal, 

 and Finch) were picked up in turn by the hydrophone and the ves- 

 sels located before they could be seen. Several times signals from 

 two or three of the lightships could be heard and located at the same 

 time and the position of the Von Steuben determined by cross- 

 bearings. 



It was not expected that the bell signals from the Nantucket 

 lightship could be heard as the course of the Von Steuben lay well 

 to the southward of this vessel and the listeners turned in for the 

 night. The writer's assistant. Ensign D. W. McElroy, U.S.N.R.F., 

 having awakened at about i A.M., decided to listen on the hydro- 

 phone and heard the bell signals from this vessel coming in clearly 

 and distinctly. The Von Steuben at this time was steaming at full 

 speed. The bell was followed for two hours, during which time the 

 light on the Nantucket lightship was not sighted. The range and 



PROC. AMER. PHIL. SOC. , VOL. 1 IX., X, DEC. I5, I9 20. 



