Proceedings Of The Marine

WIN 2015

Proceedings magazine is a communication tool for the Coast Guard's Marine Safety & Security Council. Each quarterly magazine focuses on a specific theme of interest to the marine industry.

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90 Proceedings Winter 2014 – 2015 www.uscg.mil/proceedings A nswers Deck 1. A. Two masthead lights forward, a stern light, and a towing light vertically above the stern light. Incorrect answer. B. A masthead light forward, two masthead lights aft, a stern light, and a towing light vertically above the stern light. Correct answer. Reference: International and Inland Rule 23 and Rule 24. Rule 23(a) states "a power driven vessel underway shall exhibit: (i) a masthead light forward; (ii) a second masthead light abaft of and higher than the forward one except that a vessel of less than 50 meters in length shall not be obliged to exhibit such light but may do so;" Rule 24(a) states "A power driven vessel when towing shall exhibit: (i) instead of the light prescribed in Rule 23(a)(i) or 23(a)(ii), two masthead lights in a vertical line. When the length of the tow measuring from the stern of the towing vessel to the after end of the tow exceeds 200 meters, three such lights in a vertical line;(ii) side lights; (iii) a stern light; (iv) a towing light in a vertical line above the stern light;" C. No masthead light forward, two masthead lights aft, a stern light, and a towing light vertically above the stern light. Incorrect answer. D. Three masthead lights forward, one masthead light aft, and two towing lights in a vertical line at the stern. Incorrect answer. 2. A. Three times the circumference of a manila line. Correct answer. Reference: American Merchant Seaman's Manual, Hayler and Keever, Seventh Edition, Page 3-1. "The length of a wooden block in inches should be about three times the circumference of the fber rope to be used with it." B. Five times the diameter of a manila line. Incorrect answer. C. Twice the diameter of its sheaves for manila line. Incorrect answer. D. Twenty times the diameter of a manila line. Incorrect answer. 3. A. allow leeway according to the weather conditions. Incorrect answer. B. proportionally set the number of degrees of rudder response per degree of course error. Incorrect answer. C. set the null band or dead zone signal before actuating the rudder. Correct answer. Reference: Electronic Navigation Sys tems, Tetley and Calcutt, Third Edition, Page 327. D. set the speed at which the rudder responds. Incorrect answer. 4. A. 1.3 ° W GE, 1.3 ° E DEV. Incorrect answer. B. 0.0 ° GE, 0.0 ° DEV. Incorrect answer. C. 1.3 ° W GE, 1.3 ° W DEV. Incorrect answer. D. 1.3 ° E GE, 1.3 ° E DEV. Correct answer. Reference: The American Practical Navigator, Bowditch, 2002 Edition, Page 273 and Table 23. Declination is derived from the daily pages of the Nautical Almanac for the GMT of the observation Declination = 23 ° 26.3'N sin Amp = (sin Dec)/(cos Lat) sin Amp = (sin 23.4383 °)/(cos 52.6483 °) sin Amp = 0.655608031 °; Amp = 40.9658 ° The amplitude is applied north of west because the sun is setting and the declination is north; Amp = 270 ° + 40.9658 ° Amp = 311 ° True A correction from Bowditch Table 23 is applied to the observed gyro bearing because the body's center is on the visible horizon. Table 23 correction = 1.3 ° Observed gyro bearing = 311 ° Observed gyro bearing = 311 ° - 1.3 ° = 309.7 ° Gyro error = the difference between True bearing and Gyro bearing Gyro error = 311 ° – 309.7 ° = 1.3 ° East True Course = Gyro Course +/- Gyro Error True Course = 352 ° + 1.3 ° E True Course = 353.3 ° Compass Deviation Magnetic Variation True 358 ° 1.3 ° East 359.3 ° 6 ° West 353.3

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