SPECIMEN EXAMINATION FOR SECOND MATE 



35 



12. AIDS TO NAVIGATION. 



What is the meaning of a red nun 

 marked with a yellow triangle as illus- 

 trated? 



lELLOW 

 RED 



What is the meaning of the "class" 

 of a buoy as specified in the U.S. Coast 

 Guard Light List? 



When a buoy is in position during a 

 certain period of the year only, how 

 may the dates when the buoy is avail- 

 able be determined? 



Describe the use of a range (or lead- 

 ing lights) in entering or leaving a 

 harbor. What precautions must be ob- 

 served in the use of such ranges? 



What is the significance of the shape 

 of unlighted buoys as used in the lat- 

 eral system in United States waters? 



On a clear, dark night, a light is 

 sighted just breaking clear of the hori- 

 zon. If your height of eye is 50 feet and 

 the charted visibility of the light is 12.5 

 miles, what is your distance from the 

 light? 



Define exactly what is meant by a 

 group occulting light. (Candidates may 

 submit a sketch such as that contained 

 in the light list to help demonstrate 

 complete comprehension of the term). 



Name the different types of buoys 

 sketched. 



Where it is desired to show the need 

 for particular caution, at important 

 turns, etc., what light period is given 

 buoys? 



What is indicated by the white buoy 

 with green top as sketched? 



GREEN 



NHITB 



How would you identify a lighthouse 

 in the daytime? 



Where are station buoys found and 

 what is their function? 



How far could you see a powerful 

 navigational light whose height is 100 

 feet from the bridge of a vessel where 

 your height of eye would be 80 feet 

 above the water? 



What word indicates color variations 

 in the characteristics of a light? 



Define exactly what is meant by an 

 interrupted quick flashing light. (Can- 

 didates may submit a sketch such as 

 that contained in the light list to demon- 

 strate their complete comprehension of 

 the term) . 



A 



