HAYES— DETECTION OF SUBMARINES. 47 



marine sound detector and a submarine signal device such that its 

 signals can be distinctly heard at a distance of at least five miles. 

 During fog each boat should periodically signal by code its course 

 and possibly its speed. By picking up such signals on its listening 

 device any boat can avoid collision since it will know the bearing, 

 course, and speed of all ships within a radius of five miles. 



Such an arrangement should not only eliminate all possibility of 

 collisions but should enable our whole Merchant Marine to keep 

 moving at practically full speed at all times, thereby placing it in a 

 better condition for competing with the Merchant Marines of other 

 nations than it otherwise would be. 



U. S. Naval Experimental Station, 

 New London, Conn. 



