Question 11Navigation Problems
70% to passOn 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.
Related Questions
Q43:On 22 February your 1857 DR position is LAT 23°46.0'S, LONG 93°16.5'E. You obser...
Q77:On 29 July your 1930 zone time DR position is LONG 164°26.0' E. At that time you...
Q61:On 4 September your 1813 zone time DR position is LAT 24°18.0' S, LONG 95°16.0' ...
Q17:On 2 October your 1845 DR position is LAT 28°09.2'S, LONG 167°48.1'E. You observ...
Q23:You observe the lower limb of the Sun at a sextant altitude (hs) of 41°29.8' on ...
Ready to test your knowledge?
Take a Navigation Problems Practice ExamOfficial Resources