submarines and who observed these inadequacies in personnel 

 as well as equipment, the widespread use of this simple method 

 of assuring proper operation of vital equipment was extremely 

 important . 



Another kind of assistance was the development of a 

 system of measuring the sound conditions of submarines oper- 

 ating at various depths and speeds The New London Laboratory 

 had collected data at Pearl Harbor on the noise produced by 

 submarines as a direct result of cavitation and had made 

 studies to link the noise with the speed and depth. As a 

 result it was concluded that a definite relation could be 

 established between speed and depth, and cavitation, which 

 would vary only from boat to boat 



Field engineers assigned to ComSubPac evolved field 

 methods of making cavitation measurements,. Procedures were 

 developed for laying out operating schedules and preparing 

 the gear for test runs, Considerable practice was required 

 to distinguish cavitation from other noises . 



The data, or "boat signature , " was compiled for each 

 submarine tested and a chart was prepared showing the record 

 of noise level before and after propeller cavitation at 

 various speeds and depths , These were curves of speed versus 

 depth showing the boundary or threshold between cavitation 

 and the absence of cavitation. These charts were then pre- 

 sented to the submarine skippers 



Since propeller cavitation and other noise sources vary 

 from time to time, particularly in war patrols v\rhen depth 

 charges are dropped or when operating in shallow waters, 

 this method of measurement was extremely important. Skippers 

 were able to operate under certain conditions with at least 

 a greater peace of mind when they had this information,, Thus, 

 field engineers even helped to improve tactical operations, 



This unique cooperative effort of the men from the 

 laboratories, factories, naval commands and forces afloat 

 efficiently accomplished far more than anyone expected in 

 the beginning. Because the engineers had been carefully 

 selected and trained they were able to "grease the wheels" 

 of ASW operations and weld the men and equipment into a 

 single, highly efficient team,, This could not have been 

 done if all hands had not 'worked together. This cooperation, 

 in summary, enabled the field engineers to; 



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