HAYES— U. S. NAVY MV TYPE OF HYDROPHONE. 393 



On occasions when the radio is temporarily disabled, as for in- 

 stance, when the antenna is carried away by a gale, the use of the 

 hydrophone for communication purposes may be vital indeed. 



The Hydrophone as an Accelerator of Commerce. 



Doubtless, the most fruitful aspect from a financial point of view 

 of the advent of the modern hydrophone is its use in speeding up 

 commerce. When one considers the enormous loss in time and 

 money which is occasioned by vessels being frequently obliged to lie 

 idle when waiting for clear weather in order to enter or leave port 

 or to otherwise navigate in restricted waters, it is at once evident 

 that a device which will eliminate such delays needs little advertis- 

 ing. The aids thus afforded will soon cancel the expense of the 

 installation and will subsequently pay high interest upon the in- 

 vestment. 



The development of the art to date justifies the prediction that 

 harbors and channels will be provided with suitable submarine 

 sound beacons which will enable a vessel fitted with a hydrophone to 

 safely navigate in such waters during thick weather. 



Examples of the Use of the MV Hydrophone. 



Having discussed some of the theoretical details of the MV hy- 

 drophone and having considered certain lines of its future develop- 

 ment and application, it will now be of interest to relate a few 

 actual experiences and results which have been obtained with various 

 installations of this type of hydrophone upon certain ships of the 

 U. S. Navy. These instances will serve to demonstrate the value 

 of this device as an aid and safeguard to navigation. 



U. S. S. VoN Steuben. 



Much use was made of the hydrophone installation on the Von 

 Steuben during her several trips as a transport plying between New 

 York and Brest. A particular instance will be cited. 



Throughout one of her return trips cloudy weather was encoun- 

 tered, so that navigation was of necessity by "dead reckoning" 

 m.ethods without the aid of solar checks. Referring to the chart 



