between probe and ship permits pulse propagation measurement at low carrier 

 frequencies . 



However, if dispersion can be proven to be a negligible problem, 

 this advantage disappears. On the other hand the XSV has the inherent dis- 

 advantage of its principle of measuring the integral of sound velocity over 

 the full instantaneous depth of the probe and this adds one differentiation 

 to the computation of the velocity profile. 



In summary, it can be said that further study may show that the 

 most cost-effective shipboard routine for ascertaining oceanographic con- 

 ditions for sonar pupposes may include one or more hybrid or special purpose 

 devices in addition to the regular expendable BT. It is thus our finding 

 in this limited study that the Navy should continue the development and de- 

 ployment of the expendable BT, that the development of the XSV should be 

 investigated, and that a hybrid expendable conductivity-temperature device 

 (XCT) be explored as a means of determining the variability of onshore and 

 shallow-water sonar oceanographic conditions, pending the availability of 

 an XSTD. 



50 



Arthur 2D.lLittlc.Ilnr. 



