Part L— MAGNETIC ADJUSTMENT 



CHAPTER I. PROCEDURES FOR MAGNETIC COMPASS 

 ADJUSTMENT (CHECK-OFF LIST) 



Note. — If the magnetic adjustment necessitates (a) movement of degauss- 

 ing compensating coils, or (6) a change of Flinders bar length, the coil com- 

 pensation must be checked. Refer to ch. X. 



1. A. Dockside tests and adjustments. 



1. Physical checks on the compass and binnacle. 



(a) Remove any bubbles in compass bowl (art. 72). 



(b) Test for moment and sensibility of compass needles 



(art. 73). 



(c) Remove any slack in gimbal arrangement. See (g) 



below. 



(d) Magnetization check of spheres and Flinders bar 



(art. 74). 



(e) Alignment of compass with fore-and-aft line of ship 



(art. 76). 

 (/) Alignment of magnet trays in binnacle. 

 (g) Alignment of heeling magnet tube under pivot point 



of compass. 

 (h) See that corrector magnets are available. 



2. Physical checks of gyro, azimuth circle, and peloruses. 



(a) Alignment of all gyro repeater peloruses or dial 

 peloruses with fore-and-aft line of ship (art. 75). 



(5) Synchronize gyro repeaters with master gyro. 



(c) Make sure azimuth circle and peloruses are in good 

 operating condition. 



3. Necessary data. 



(a) Past history or log data which might establish 

 length of Flinders bar (arts. 77 and 96) . 



(6) Local apparent time and watch setting (arts. 63, 64, 



and 65). 



(c) Azimuths for given date and latitude (ch. VI) . 



(d) Ranges or distant objects in vicinity (local charts). 



(e) Correct variation (local charts). 



(/) Degaussing coil current settings for swing for resid- 

 ual deviations after adjustment and compensation 

 (Ship's degaussing folder). 



