Question 11Navigation Problems

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On 28 October at 1754 ZT, your vessel's DR position is LAT 28°30' N, LONG 63°24' W. At this time, you obtain a sextant altitude (hs) of Polaris reading 28°42.6', with an index error of 2.4' on the arc. Your chronometer reads 09h 50m 00s, and is 4m 14s slow. What is your latitude by Polaris, given a height of eye of 28 feet (8.5 meters)?

A 28°30.6'N
B 28°25.2'N
C 28°34.9'N
D 28°41.3'N
AI Explanation

The correct answer is C) 28°34.9'N. To determine the latitude by Polaris, we need to use the formula: Latitude = Polaris Altitude + Refraction Correction - Index Error. Given the information provided: - Polaris Altitude (hs) = 28°42.6' - Index Error = 2.4' (on the arc) - Height of Eye = 28 feet (8.5 meters) Applying the formula, we get: Latitude = 28°42.6' + Refraction Correction - 2.4' Refraction Correction for a height of eye of 28 feet is approximately 0.6'. Therefore, the final latitude is 28°42.6' - 2.4' + 0.6' = 28°34.9'N. The other options are incorrect because they do not accurately account for the given information and the proper calculation of latitude by Polaris.

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Official Resources
USCG Navigation Rules (COLREGS) 33 CFR Navigation Rules USCG National Maritime Center
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