IV. COMPARISON OF METHODS AND RECOMMENDATIONS 



A. Comparison of Direct and Indirect Methods 



In Table IV-1 we have compared these various devices on the 

 basis of depth capability, measurement accuracy in deep and shallow water, 

 the initial cost, the required time on station for a profile, the speed of 

 readout and the potential for improvement. In Table IV-2 we have outlined 

 some of the Navy's needs for information on sound velocity and the instru- 

 ments which can satisfy them. In both tables we have assumed the existence 

 of a suitable expendable velocimeter. Table IV-2 may be briefly summarized 

 as follows: 



1. For survey needs, existing instruments are adequate in both 

 deep and shallow water. (By "survey" we imply that the ship 

 can be either stationary or proceeding slowly.) The available 

 velocimeters are well suited to any survey work, and their 

 performance is quite adequate when care is taken in their 

 operation. 



2. For tactical needs, expendable instruments are required. 



The question arises as to the potential of the velocimeter to 

 fulfill future needs. 



40 



Arthur ZD.3Uttle.2lnr. 



