On 17 March your 0800 zone time DR position...

Question 1 of 2707066636eea28f7522a1c51ab4e

On 17 March your 0800 zone time DR position is LAT 21° 27.0' N, LONG 65° 25.0' W. Your vessel is on course 105° T at a speed of 17.5 knots. What is the zone time of local apparent noon (LAN)?

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Question 1 of 27070

On 17 March your 0800 zone time DR position is LAT 21° 27.0' N, LONG 65° 25.0' W. Your vessel is on course 105° T at a speed of 17.5 knots. What is the zone time of local apparent noon (LAN)?

🔍 Key Concepts

• Local Apparent Noon (LAN) occurs when the Sun is on your local meridian (over your longitude). • The ship’s longitude at LAN, not at 0800, controls the LAN time. • Relationship between longitude and time: 15° of longitude = 1 hour = 60 minutes, or 1° = 4 minutes of time.

💭 Think About

• Start by advancing your 0800 DR position ahead to about 1200 using the given course and speed. How many nautical miles will you travel in 4 hours, and how much of that distance is east–west? • From the east–west distance (departure) and your average latitude, what is the change in longitude between 0800 and LAN? Will your longitude be greater or smaller (farther east or west)? • Once you have the approximate longitude at LAN, convert that longitude to time using 4 minutes per degree. Then adjust that local mean time to zone time using the correct time zone for 65°–70°W.

✅ Before You Answer

• Be sure to compute distance run from 0800 to about noon correctly: Speed × Time (in hours). • Use departure = distance × sin(course) to find the east–west component, then convert that departure to change of longitude using the cosine of your latitude. • Confirm the correct time zone: which integer multiple of 15° of longitude contains your DR longitude (60°–75°W, 75°–90°W, etc.), and is the zone number plus or minus relative to GMT?