On 24 January your 0700 zone time DR...

Question 1 of 2707066636eea28f7522a1c51ad89

On 24 January your 0700 zone time DR position is LAT 22°25.0'N, LONG 46°10.0'W. Your vessel is on course 110°T at a speed of 12.0 knots. What is the zone time of local apparent noon (LAN)?

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Question 1 of 27070

On 24 January your 0700 zone time DR position is LAT 22°25.0'N, LONG 46°10.0'W. Your vessel is on course 110°T at a speed of 12.0 knots. What is the zone time of local apparent noon (LAN)?

🔍 Key Concepts

• How to compute the time of Local Apparent Noon (LAN) from a DR longitude and estimated longitude at meridian passage • Conversion between difference in longitude and time (degrees to minutes of time) • Effect of the vessel’s east-west movement on the meridian passage time

💭 Think About

• From 0700 to LAN, your longitude will change. In which direction and by how many minutes of longitude per hour based on your course and speed? • How do you convert the total east-west longitude change between 0700 and LAN into a time correction to 1200 zone time? • Is the Sun crossing your DR meridian earlier or later than 1200 local zone time if you are moving east?

✅ Before You Answer

• Compute the east-west component of your speed using the course 110°T to find miles of longitude made good per hour at LAT 22°25.0'N • Use the rule of thumb that 15° of longitude = 1 hour of time to convert the longitude change into minutes of time • Decide if you should add or subtract this time correction from 1200 zone time based on whether you are moving toward or away from the Sun (east or west)