8 



UNITED STATES COAST GUARD 



What do you mean by "arming" the 

 lead? 



Describe an engine room telegraph. 



What is a taflfrail log? 



How do you mark a fifty-fathom lead 

 line? 



What is a protractor? 



Upon what principle do echo sounders 

 operate? 



Describe the mechanical sounding 

 machine, its parts, and the procedure 

 for taking soundings. 



Why is it necessary to calibrate or 

 compensate radio direction finders? 



How would you examine a sextant for 

 detection of error due to the horizon 

 glass being out of adjustment for per- 

 pendicularity? 



What conditions are likely to cause 

 patent logs to give inaccurate read- 

 ings? 



On 12 June, at 0100 GMT a radio 

 time signal shows chronometer "C" to 

 be lm-42s slow. On 17 June, at 0900 

 GMT a radio time signal shows chro- 



nometer "C" to be lm-50s slow. On 18 

 June, at 0100 GMT an observation 

 was taken. Assuming a constant chro- 

 nometer rate, what correction should 

 be applied to chronometer "C"? 



On 12 December, a radio time signal 

 at 0300 GMT shows chronometer "A" to 

 be 12m-29s slow. On 14 December, a 

 radio time signal at 1200 GMT shows 

 chronometer "A" to be 12m-10s slow. 

 On 16 December, an observation is 

 taken at 2100 GMT. What correction 

 to chronometer "A" is, required, assum- 

 ing there was a constant chronometer 

 rate? 



In taking the time for an observa- 

 tion, how should the chronometer be 

 read; i.e., in what sequence do you note 

 the hours, minutes and seconds of time 

 on the chronometer? 



If your vessel was on the meridian 

 of Greenwich and the sun was on the 

 meridian; i.e., its bearing was due 

 South or due North, would the chronom- 

 eter read 12-00-00 if it had no error? 



18. TIDES AND CURRENTS. 



What is a reference station as used 

 in the tide tables? 



What is meant by the "height of 

 tide"? 



What is meant by the "range of the 

 tides"? 



At Portland, Maine on 16 August 

 1958 : 



(a) What is the tabulated time 

 and height of a.m. low water? 



(b) If your chart for Portland 

 showed a depth of 24 feet for a given 

 area, what would be the depth at low 

 water for that area? 



(c) If your vessel had its clocks 

 set for Eastern Daylight Saving Time, 

 what would be the ship's time at low 

 water? 



At Balboa, Canal Zone, Panama on 

 6 March 1958: 



(a) What is the tabulated time 

 and height of p.m. high water? 



(b) If your chart showed a depth 

 of 20 feet for a given area in this 

 vicinity, what would be the depth at 

 high water at this area? 



NW of Capul Island, San Bernardino 

 Straits, P. I. on 16 November 1958: 



(a) What is the tabulated time 

 and velocity of maximum p.m. flood 

 current? 



(b) In what direction does the 

 flood current flow at this position? 



(c) What time meridian is used in 

 tabulating the times given for the cur- 

 rents? 



19. OCEAN WINDS, WEATHER AND CURRENTS. 



What is "humidity"? 



What is a "psychrometer"? 



Describe the Centigrade scale for 

 measuring temperature. 



Convert 15° Celsius (Centigrade) 

 into the temperature Fahrenheit. 



What is atmospheric pressure and 

 what instruments may be used to meas- 

 ure it? 



What is normal atmospheric pres- 

 sure? 



