THEORY OF COMPENSATION 



99 



NE./SW. axis. A compensating component may therefore be created 

 by energizing the NE./SW.-M coil until the compass indicates the 

 original heading. This siinply means that the current in the 

 NE./SW.-M coil is adjusted to compensate for any deviation caused 

 hy the M degaussing coil on a NE. or SW. heading. Conversely, with 

 the ship on a NW. or SE. heading any deviation due to the M de- 

 gaussing coil is corrected by use of the NW./SE.-M coil. The full 

 details of all such compass coil compensation are presented in chapter 

 X. These principles of component compensation apply whether the 

 component axes are intercardinally or cardinally arranged. 



NW/SB Axis 



NV/SE Coil 



Figure 52. — Intercardinal axes. 



124. If the deviation from degaussing is greater than 90°, or com- 

 pensation with any degaussing coil energized is difficult, that degauss- 

 ing coil should be energized with reversed polarity in order to facilitate 

 adjustment. Compensation is similarly simplified by always compen- 

 sating the larger of the two horizontal components first. 



After both horizontal components of coil compensation have been 

 adjusted for each effective degaussing coil, it is advisable to check 

 deviations on a compass heading somewhere between those used for 



