122 SUBMARINE SIGNALING AND A PROPOSED 



This apparatus was tested by the inventor in Boston Bay, and was heard at a 

 distance of 31 knots when suspended in open water from the Boston lightship at a 

 depth of 12 feet. 



The first tests of the oscillator on board the submarines were not successful 

 in reaching more than half a mile, this lack of efficiency being attributed to the 

 fact that the hull was used as a diaphragm by connecting the oscillator thereto in- 

 stead of installing an attuned diaphragm. Afterwards four sets each were installed 

 upon the Delaware and Wyoming, the hull likewise being used as a diaphragm. 

 With these vessels a maximum range of three miles was attained in the final tests 

 as reported in October, 1913. 



In July, 1914, two sets were mounted on submarines K-i and K-2 outside the 

 hull of the vessel, by securing them to the superstructure deck facing forward. 

 The results of the tests made off Newport, R. I., gave a readable maximum range 

 of 6 knots, with a minimum range of 2 knots except when the sound shadow of the 

 conning-tower interfered. 



On the recent tests made by the U. S. S. Arkansas and Utah, the former car- 

 ried a 5-kilowatt oscillator suspended in the water from the boat crane, using 25 

 feet submergence, while another set was mounted with a tuned diaphragm riveted 

 to the hull of the Utah. A maximum range of 10 knots was obtained in this test 

 made on November 7, 1914. 



The oscillators were used both for sending and receiving, and by the use of a 

 Morse key the speed was equal to that of the aerial wireless. 



The difficulties yet to be overcome for an all-round submarine signal system 

 are: — 



1. To attain an equal radius in all directions for sending. All systems using 

 a diaphragm are directed. 



2. To attain an equal audibility in all directions for receiving. 



3. To eliminate the sound shadows caused by the vessel itself and the effect 

 of the wake. 



Unless these deficiencies can be overcome, submarine signals will not be en- 

 tirely satisfactory for naval purposes. 



The same defects are undesirable for fog navigation but not vital, and an arc 

 of audibility somewhat greater than the 20 points of visibility required for the 

 running lights of a vessel would, if necessary, suffice for safety. 



Many who are not skilled in navigating or handling vessels might naturally 

 assume that with a satisfactory means of submarine signaling between vessels 

 under way capable of reaching 3 to 5 miles, the whole problem of safe fog naviga- 

 tion would be solved. This, however, is unfortunately far from being the case. 



Vessels under way equipped with an efficient system of submarine wireless 

 would be able to hear each other's signals farther than the average range of the 

 steam whistle and would be able to signal their speed and course. They would also 

 be enabled to ascertain on which side of the vessel the signals were received by 

 means of the microphones and receiving sets already shown or by analogous 

 methods. 



