THE PROBLEM 
Investigate subsurface hydrodynamic phenomena in the sea; 
specifically, study internal waves by providing a mobile apparatus 
for the measurement of internal waves. 
RESULTS 
1. A submarine-mounted vertical array of thermistors for 
temperature measurements at several levels was designed, con- 
structed, and tested. 
2. The precision (repeatability), using probable error as 
criterion, is +0.0032°C. The accuracy (absolute) is +0.003°C 
over the usable range. 
3. Data output is in digital form. 
4, The digital data are reduced to give depth of isotherms 
(i.e., internal waves) as a function of position along the track. 
Techniques for accomplishing this with a high speed computer 
have been devised and tested. 
RECOMMENDATIONS 
Accord recognition to the importance of the submarine as a 
working platform for the oceanographer. Use a submarine, es- 
pecially during the season of well-developed thermoclines, for 
the study of internal waves. 
ADMINISTRATIVE INFORMATION 
This work was done under S-RO011 01 01, Task 0401 (NEL 
L4-3) by members of the Signal Propagation Division. It com- 
menced in July 1959, and was completed in November 1961. This 
