118 



DPG arm was taken as the average of the corrected values found from 

 the digital and wrist compass measurements. The values of each 

 correspond to the heading towards which the end of each arm points 

 with respect to magnetic north. The values were corrected to true 

 north using the 1982 value of the variation for Cape Hatteras, N.C. 



This investigation indicates the importance of careful 

 redundant checks of instrument orientation when working near a steel 

 structure. The analysis technique outlined here requires at least 

 one pair of compass measurements made on opposite sides and 

 equidistant from the appoximate center of the metal structure. The 

 investigation suggests that simple wrist compasses may be adequate 

 for determining instrument orientation if special care is taken during 

 the measurement and interpretation of the results. 



C. First Month's Inspection 



The instrument was re-inspected on June 15, 1982 — one month 

 after installation. The cradle and instrument had settled into the 

 seafloor only four or five inches with minimal disturbance to the bed 

 around the gauge. The cable had buried itself deeply immediately 

 outside of the service box. The system's anti-fouling agents had 

 thus far worked excellently. 



