2 UNITED STATES COAST GUARD 



GIVEN: 



No. 1 No. t No. S 



Date IJanuary 1958 2 May 1958 3 September 1958 



GMT 12h-04m-57s 5h-29m-33s 21h-09m-43s 



Long. 57°-32'.0 West 15°-29'.0 East 157 °-18'.0 West 



Required: The meridian angle and cases. Indicate whether the sun is east 



declination of the sun in each of the 3 or west of the meridian in each case. 



5. CHART NAVIGATION. 



What regions of the earth may not 

 be shown by the ordinary Mercator 

 chart projection? 



What would be the appearance of 

 straight lines on a Mercator chart if 

 transferred to a globe? 



What government agency of the 

 United States publishes charts of for- 

 eign waters ? 



What government agency of the 

 United States publishes charts of the 

 United States and its possessions? 



If you wished to measure the distance 

 between point "A" at Latitude 30° 

 and point "B" at Latitude 40° on a 

 Mercator chart with the dividers set to 

 measure 30' at each step, at what two 

 points on the latitude scale would you 

 set each leg of the dividers in order 

 to obtain the most accurate measure- 

 ments ? 



How does a great circle appear when 

 plotted on a gnomonic chart ? 



Name the various instruments or de- 

 vices that may be employed in deter- 

 mining the course on a Mercator chart. 



What chart would you consult to de- 

 termine weather conditions, currents, 

 or locations where ice might be encoun- 

 tered ? 



Distinguish between small scale 

 charts and large scale charts, and state 

 the use of each. 



How are charts kept up to date ? How 

 would you know when a chart was last 

 corrected ? 



Having once determined the course 

 to sail a great circle, can this course 

 be used until the destination is 

 reached ? 



How may the likelihood of encoun- 

 tering gales be determined from a pilot 

 chart? 



How is normal barometric pressure 

 and temperature indicated on the pilot 

 charts? 



What is the true shape of the earth? 



Describe the polyconic projection. 



Describe the tidal current charts pub- 

 lished by the U.S. Coast and Geodetic 

 Survey. 



How is the ship's position deter- 

 mined by means of cross bearings (3 

 bearings) which are taken at different 

 times? 



When observing cross bearings of 

 objects, how much should their bear- 

 ings differ to obtain a good fix? 



When obtaining distance off by two 

 bearings on a single object, how is the 

 distance run between bearings deter- 

 mined? 



Explain the use of the 26%° to 45° 

 bearing, and state how it can be used 

 to predict the time due abeam. 



In taking a vertical sextant angle 

 to determine the distance off an object, 

 where would you find the height of 

 the object? 



Explain the 30-60 case, or % rule, 

 for determining distance off an object 

 by means of two relative bearings on 

 the object and the run between the 

 bearings. 



For what purpose is the "danger 

 bearing" used by the navigator? 



In the vertical danger angle, what 

 is indicated when the sextant angle is 

 found to be greater than that deter- 

 mined by the desired distance off the 

 vertical object? 



By whom are chart catalogues issued, 

 and what information do they contain? 



What is meant by "Doubling the an- 

 gle on the bow," and how is this method 

 used? 



What information is contained in the 

 Coast Guard "List of Lights and other 

 Marine Aids"? 



What Government agency publishes 

 the Tide Tables? 



What publication contains astronom- 

 ical data for use by mariners? 



How may a range provide a bearing? 



Where can detailed information about 

 ocean currents be obtained? 



State the use of the "bow and beam" 

 or "4 point" bearing, and describe how 

 one is obtained. 



State how middle latitude sailing can 

 be used when a vessel's course crosses 

 the equator. 



