102 



HANDBOOK OF MAGNETIC COMPASS 



128. Occasionally it will be noticed that the compass deviates con- 

 siderably when the degaussing coils are changed rapidly. It should, 

 if correctly compensated, settle back to the proper reading after a 

 few seconds. This condition is due to the difference in the rate of 

 saturation of the degaussing coil and the compensating coil, and 

 should not be alarming since in actual 'usage degaussing is never 

 changed rapidly. 



NAVSaiPS (2S0) 



itof(iM3) MAGNETIC COMPASS TABLE 



FLASH 



U. S. S._ 



ST'D [2 STEERING n OTHER_ 



Nn AP 999 



icIeType: Now Sfd /.»»^/.=.lU. MK. VTT ' 



Compass 7i " Mal<e_Ritchie No._352£L__ 



Type CC Coils liG!i _ Date T -T^j t ^ . 10/, /^ 



ei 'CLC/DO HOT cycle dg coils when securing 



U AlnieC^ED ronl/ AFT AT AVERAGE DlSTANCE___li»i FROM CARD 



2 AlnlcOfiED port;»b»at average distance \5J1 • from card 



2 ~ 7 • SPHERES AT 13.5 — '- — X- 0,R2 «e««ft/GOOD/S»(*ef 

 heeling magnet RED;«fcBS UP 15»5 : FROM COMPASS CARD 



JL2_ 



1 OF BAR FORWARD/' 



H=. 0.19Q z-.±ajaa 



Ilote; 3 " gun fo rward of compass must be 

 trainea rore-and-al't, 



SIGNED \ n f\ 



SUBMinED gtr ■ )Vd-tCvN- oMvg-^ 



INSTRUCTIONS 



1. This form shall be filled out by the adjuster (if available) 

 or the navigator, one for each magiietic compass, as follows: 



a. After each normal adjustment of the magnetic compasses. 



i. After each degaussing compass compensation coil adjust- 

 ment. 



0. Each time the vessel crosses the magnetic equator. 



d. As of 30 June each year if it has not already been submit- 

 ted, as above, during the previous 12 months. 



2. When the "DG ON" curve is taken, the degaussing coils 

 must be set to the proper value for latitude and heading as speci- 

 fied in DGP, 40 series in the Degaussing Folder. 



( Charts dated 10 Dec, 19/t3) 



3. Each time the form is filled out, a copy is to be sent to 

 BuShips. 



4. The adjuster should determine whether the MPQ coils 

 should be cycled when securing and so indicate on the form. ' 



5. The first time this report is filled out for a given compass, 

 the following performance data should be included: 



a. Compass steady /urpfr e n d s' at sea. 

 h. Cnn i piM-g i low/ fl lnaoinTij^ntinlr^r , 



c. Deviations nhnngB/remain reliable. 



d. Sweeping operations do/do not create unreliable devia^ 



tions. 



e. Degaussed deviations ^aj^do not vary. 



/. Overhauls, gunfire, flashing, wiping, deperming, with 

 dates and effect on magnetic compass. 



6. On subsequent submissions of this report enter only per- 

 formance data (par. 5) which has changed from that reported 

 on the previous report, or which is seriously afltecting the mag- 

 netic compass. 



Figure 54. — Deviation table — Form NBS 1104. 



Under certain, conditions of deperming^ flashing.^ or wiping it may 

 be necessary to remove the Flinders bar, spheres, compass, and other 

 compass equipment from the ship in order to avoid their becoming 

 adversely affected by the strong magnetic fields which are employed 

 in the process. Under some conditions the removal of equipment is 



