Part II.— DEGAUSSING COMPENSATION 



CHAPTER X. PROCEDURES FOR DEGAUSSING COMPASS 

 COMPENSATION (CHECK-OFF LIST) 



Note. — If the coil installation or compensation necessitates changing any of 

 the magnetic correctors, the magnetic adjustment should be checked. Refer to 

 chapter I. Extreme care is essential in making the coil compensation so as to 

 avoid magnetizing the Flinders bar or spheres. 



107. A. Dockside tests. 



1. Physical checks of binnacle and coils : 



(a) Magnetization check of spheres and Flinders bar (art. 



74). 

 (h) See that spheres are in correct position (art. 78). 

 (g) See that correct length of Flinders bar is in holder 



(arts. 77 and 95 to 99 inclusive). 



(d) Flinders bar coil must be mounted high and securely. 



(e) Sphere coil alignments and mechanical security. 



(/) "O", "K", or "T" coil alignments and mechanical 



security. 

 (g) Watertightness of coil wiring. 

 (h) See that all fittings are nonmagnetic. 



2. Electrical checks on control boxes and compass coils : 



(a) Check each coil for continuity of circuit. 



(6) Check each set of coil leads for identity, and tag, by : 



(1) Visual wiring check. 



(2) Ohmmeter test (art. 129). 



(3) Battery and compass test. (Use flashlight bat- 



tery to energize a coil and explore for effective 

 coil with small compass). 



(<?) Check that series coil windings are not bucking. 



(d) Check each coil for insulation resistance to ground and 



to all other coils. 



(e) Connect proper group of coil windings to each compass 



coil box (art. 120). 

 (/) Check that control boxes are watertight. (Terminal 

 tubes, packing gaskets, etc.; 5 pounds per square 

 inch air pressure may be used.) 



75 



