Question 55Navigation Problems

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On 17 November in DR position LAT 01°14.4'S, LONG 148°45.5'E, you take an ex-meridian observation of the planet Venus at upper transit. The chronometer time of the sight is 05h 31m 42s, and the chronometer error is 01m 50s fast. The sextant altitude (hs) is 64°41.1'. The index error is 1.8' off the arc, and your height of eye is 50 feet. What is the latitude at meridian transit?

A LAT 01°20.2'S
B LAT 01°16.3'S
C LAT 01°14.4'S
D LAT 01°18.0'S
AI Explanation

The correct answer is D) LAT 01°18.0'S. To determine the latitude at meridian transit, we need to calculate the observed latitude (Lob) using the ex-meridian observation of Venus. With the given information, we can apply the formula for ex-meridian observation to find the latitude. The key steps are: 1. Correct the sextant altitude (hs) for index error and height of eye to get the true altitude (h). 2. Use the ex-meridian formula to calculate the observed latitude (Lob). 3. The latitude at meridian transit is the observed latitude (Lob). The other options are incorrect because they do not match the calculated latitude of 01°18.0'S.

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