On 16 April your 0200 zone time DR position is LAT 17°18'S, LONG 168°46'E. You are on course 236°T at a speed of 16 knots. You observed 3 celestial bodies. Determine the latitude and longitude of your 0600 running fix.
• Dead reckoning (DR) track and how far you travel from 0200 to 0600 at 16 knots • How a running fix uses LOPs (lines of position) advanced or retarded along the DR track • Converting distance run on a true course into approximate changes in latitude and longitude
• From 0200 to 0600, how many hours have passed, and what total distance have you run at 16 knots? • On course 236°T in this part of the world (S latitude, E longitude), will your latitude number increase or decrease, and will your longitude number increase or decrease? • Compare each choice to the 0200 DR position: which option shows a position shifted roughly the right distance and direction from the DR?
• Compute the run in nautical miles between 0200 and 0600 and check that the change in position between 0200 DR and each option is of the same order of magnitude • Make sure the direction of change in both latitude and longitude matches a course of 236°T in the Southern Hemisphere, Eastern longitude • Check that the option you favor lies reasonably close to where a 16‑knot vessel would be after 4 hours on 236°T from the given DR, not far ahead or behind the expected DR track
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