TRANSIENT DEVIATIONS 73 



justments, if neglected. This same type of error occurs when ships 

 are docked on one heading for long periods of time. A short shake- 

 down with the ship on other headings will tend to remove such errors. 

 A similar sort of residual magnetism is left in many ships if the de- 

 gaussing circuits are not secured by the reversal sequence, as dis- 

 cussed in article 128. 



106. l>epermru(i^ ■fiaHhrng^ oi- mi ping will cliungc the magnetic condi- 

 tion of the vessel and therefore necessitate readjustment of compass 

 errors. The decaying effects of deperming are sometimes very rapid, 

 therefore it is best to delay readjustment for several days after such 

 treatment. Since the magnetic fields used for such treatments are 

 sometimes rather large at the compass locations, the Flinders bar, com- 

 pass, and such related equipment is sometimes removed from the ship 

 during these operations. 



639720—45- 



