32 



UNITED STATES COAST GUARD 



The following 3 sextant altitudes of 

 stars were obtained. The height of eye 



was 22 feet; the sextant index error 

 was 2'.0 on the arc in all observations. 



Given : 



Observation No. 1 



Star Sext. Alt 4°-19'.8 



Bar. Pressure 30.6 in. 



Temperature 92° F. 



Required: The observed altitudes. 



Observation No. S 



14''-05'.1 



980 mb 



(— ) 20° Celsius 



(Centigrade) 



Observation No. S 

 48°-56'.2 

 29.6 in. 

 48° F. 



5. CHART NAVIGATION. 



How would you assess the accuracy 

 of a nautical chart? 



What type pencils and erasers are 

 best for chart work? 



What care should be taken in using 

 pencils and erasers, to keep charts in 

 good condition? 



How is information concerning mag- 

 netic variation shown on Pilot Charts? 



Some foreign charts are published 

 with the depths sho^\^l in meters. Con- 

 vert 10 meters into fathoms. 



How should charts be stowed? 



What is the importance of the issue 

 date shown on charts? 



A vessel steams 27 minutes at 20 

 knots from bearing "1" to bearing "2." 

 Would the position of the vessel at 

 bearing "2" be at point "A," "B" or 

 "C," assuming she sailed along one of 

 the tracks plotted? 



Where may the issue date be found 

 on a chart? 



When Notices to Mariners are re- 

 ceived on board a vessel, how long 

 should they be retained before being 

 discarded? 



What is the vertex of a great circle? 



What is a chain of soundings? 



What is composite sailing, and when 

 is it used? 



How can you determine what charts 

 and publications are to be corrected by 

 the notices listed in the Notices to Mar- 

 iners? 



What government agency prepares 

 light lists for foreign waters? 



What government agency prepares 

 light lists for the United States and 

 its possessions? 



When plotting a fix by means of three 

 cross bearings taken at approximately 

 the same time, what would you assume 

 if the three bearing lines do not inter- 

 sect in a point or in a veiy small tri- 

 angle? 



What branch of the government pre- 

 pares the American Ephemeris, the Air 

 Almanac and the Nautical Almanac? 



Describe briefly the contents of at 

 least two of the three publications men- 

 tioned in the preceding question. 



Why are the backs of pages in "No- 

 tices to Mariners" left blank? 



What government agency publishes 

 the Coast Pilot? 



What government agency publishes 

 the Sailing Directions? 



Describe what is meant by the point 

 of tangcncy on a gnomonic chart. 



What information is contained in H. 

 0. No. 205, "Radio Navigational Aids"? 



