58 



HANDBOOK OF MAGNETIC COMPASS 



NAVsnirs(i») 

 !^Mi"°3t MAGNETIC COMPASS TABLE 



U.S. s.. 



FLASH 



Nn Af 999 



ST'D 1^ STEERING □ OTHER ' ' 



Binnacle Type: Navy Sfd/«.W./**lMr_MlL_jm 



Comaas s 7^ " Mak e Ritchie No.Ji52Q_ 



Type cc Coils — ICill Daiol .Tnn. 1944 



4— Alni£.aiED**Bi/AFT at average DI STANCE _12*3^—' FROM CARD 

 2 AlnJGC RFD PORT/Sta«>AT AVERAGE DISTANCE— 15^2 1 FROM CARD 



2-7' SPHERES AT T3.5 ' — x«.0,82 n a u a t /GooD/a iAq 



HEELING MAGNET RED/*b«&UP_15*-5 1 FROM COMPASS CARD 



_ — 3^ •- OF BAR F0RWA.RD/AH4. n„_ O.IQO Z«._±Q*_5^ 



Note! 3" gun forward of compass must be 

 Lrained lurt-arid-al I, 





Figure 30. 



INSTRUCTIONS 



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

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



a. After each normal adjustment of the magnetic compasses. 



b. After each degaussing compass compensation coil adjust- 



ment. 



c. 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. 



the form is filled out, a copy is to be sent to 



whether the MFQ coils 

 ) indicate on the form. 



3. Each tir 

 BuShips. 



4. The adjustor should deten 

 should be cycled when securing a 



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

 the following performance data should be included: 



a. Compass gteady /H W Db e ftdy at saa. 



b. ■ Comp ae o Ni l o^w /riaggiri^/ a tiolcy t. 



c. Deviations . o l MW i go Ttremain reliable. 



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



tions. 



e. Degaussed deviationa-dts'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. 6) which has changed from that reported 

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

 netic compass. 



C'£>AcK) 

 -Deviation table — Form NBS 1104. 



Navy Form NBS 1104 is complete and desirable in the interest of im- 

 proved Flinders bar correction and shielding conditions. Navy Form 

 NBS 1105 may be used for posting deviations at the binnacle. Figure 

 30 illustrates both sides of form NBS 1104, with proper instructions 

 and sample deviation and Flinders bar data. Should the ship be 

 equipped with degaussing coils, a swing for residual deviations under 

 degaussed conditions should also be made and data recorded as indi- 

 cated in chapter XI. 



On these swings extreme care should be exercised in taking bearings 

 or azimuths and in steadying down on each heading since this swing 

 is the basis of standard data for that particular compass. If there 

 are any peculiar changeable errors, such as movable guns, listing of 

 the ship, or anticipated decay from deperming, which would effect the 

 reliability of the compass, they should also be noted on the deviation 



