142 HANDBOOK OF MAGNETIC COMPASS 



Referring to figure 34 (b) it is noted that the existing Flinders bar (6" for- 

 ward) represents a c correction of (—0.01). The total c of the ship, then, 

 which requires correction is ( -0.01) + (—0.133) or (—0.143). Figure 34 (b) 

 shows that c of (—0.143) requires 24" of Flinders bar forward of the binnacle. 



Figure 32 shows that the existing 6" of Flinders bar is creating 1° of +D 

 error. 24" of Flinders bar from figure 32 will create 3.5° of +D. The 

 spheres must therefore be moved in to correct 2.5° additional + D error after 

 placing the 24" of bar on the binnacle. Referring to figure 31 it is noted that 

 in order to correct for this 2.5° of -fD the existing spheres must be moved 

 in from the present 15" position to approximately 13". 



In summary, the procedure at Canal Zone is as follows : 



1. Add 18" more Flinders bar to make a total of 24". 



2. Move spheres in to 13". 



3. Adjust the heeling magnet, if necessary. 



4. Swing ship and remove all remaining . cardinal heading deviations 



with the fore-and-aft and athwartship magnets and check sphere 

 correction. 



5. If compass is equipped with compensating coils, the adjustment of 



current in these coils should be refined because of the movement of 

 soft iron correctors. In this case, care should be exercised in ener- 

 gizing the degaussing coils because of the increased amount of 

 Flinders bar and, if Type "B" coils are installed, it would be well to 

 remove the jumpers in the Flinders bar circuits. 



6. Swing ship for the two customary deviation curves for degaussed and 



undegaussed conditions. 



