OUTLINE OF COURSE OF STUDY 131 



IV. Theory of magnetic compensation ( See ch. XI ) —Continued. 



E. Relation of compass compensation to compass adjustment — Continued. 



3. Degaussing deviation curve is superimposed upon normal curve. 



F. Secure degaussing by reversal, if necessary. 



G. Dockside compensation : 



1. Deflection of compass needles. 



2. Dockside interferences. 



H. Final compensation. Refinement of dockside compensation at sea. 

 I. Deviation curves : 



1. Undegaussed condition. 



2. Degaussed condition. 



V. Ship's heading. (See ch. V) : 



A. Relation between true, magnetic, and compass heading: 



1. Variation and deviation. 



2. Compass heading for adjustment. 



3. Magnetic heading for adjustment. 



4. Napier's diagram for conversion between compass and magnetic 



heading. 



5. Rules for conversion. 



ia) When correcting, apply sign property ( + E, — W). 

 (6) "Compass least, deviation east." "Compass best, deviation 

 west." 



B. Charts and instruments : 



1. Parallel rules, compass roses, variation, annual change, etc. 



2. Use of pelorus. 



3. Use of azimuth circle. 



4. Use of gyro. 



C. Methods of taking bearings : 



1. Azimuths. 



2. Gyro. 



3. Distant object. 



4. Ranges. 



5. Reciprocal bearings. 



VI. Problem session : 



A. Practice problems with variation and deviation. 



B. Practice problems using gyro, pelorus, and azimuth circle. 



C. Study of charts, choosing ranges, distant objects. 



VII. Practice session : 



A. Become familiar with different peloruses and azimuth instruments. 



B. Obtain the magnetic bearing of some distant object from your binnacle 



by averaging compass bearings found with ship on eight different com- 

 pass headings. 

 O. Determine two deviation curves for your ship on eight headings — one 

 each for compass and magnetic headings. 



D. Plot deviations as against both compass and magnetic headings. Study 



differences. 



VIII. Description of the approximate coefficients of deviation and their estima- 



tion (see ch. IV) : 



A. Coefficients A, B, C, D, and E. 



B. Estimate the coefficients for the deviation curve obtained in practice 



session, using compass headings. 



C. Other practice problems. 



