At 1800 zone time, on 7 December, your DR position is LAT 22°48'S, LONG 91°26'W. You are steering 320°T at a speed of 14.0 knots. What is the zone time of sunset?
• Use of the Nautical Almanac daily pages to find sunset for a given date and latitude • Understanding how to apply DR (dead reckoning) track from the given time to approximate the vessel’s position at sunset • Relationship between longitude, time zones, and zone time when converting from GMT to local zone time
• From 1800 zone time until around sunset, how far will the vessel move along the DR track, and will that change the latitude enough to matter for sunset? • Once you find the approximate UTC (GMT) of sunset from the almanac, how do you convert that to zone time using your longitude? • Are you selecting the correct sunset value for south latitude and the correct column on the daily page?
• Verify you used the correct latitude band and date (7 December) on the Nautical Almanac daily page for sunset • Confirm your time zone based on the longitude 91°26'W (what is the nearest standard meridian, and what is its zone description?) • Double-check that any interpolation for latitude (if needed) and any DR run between 1800 and sunset are reasonable and correctly applied
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