Your vessel is underway on a course of 115°...

Question 1 of 2707066636eea28f7522a1c51b830

Your vessel is underway on a course of 115° T at 18 knots. At 1850 a lighthouse bears 137.5° T. At 1920, the same lighthouse bears 160° T. What time will the lighthouse pass abeam to starboard?

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Question 1 of 27070

Your vessel is underway on a course of 115° T at 18 knots. At 1850 a lighthouse bears 137.5° T. At 1920, the same lighthouse bears 160° T. What time will the lighthouse pass abeam to starboard?

🔍 Key Concepts

• Relative bearings and when an object is "abeam" (90° from the bow) • Finding the rate of change of bearing over time to determine when the bearing will reach a certain value • Using proportional (linear) change in bearing over equal time intervals when speed and course are steady

💭 Think About

• From the two given bearings and times, what is the total change in bearing, and over how many minutes did that change occur? • If the vessel keeps the same course and speed, how many more degrees must the bearing change for the lighthouse to be exactly abeam to starboard? • Once you know how many more degrees of bearing change are needed, how many minutes will that take at the rate you calculated, and what clock time does that give you?

✅ Before You Answer

• Confirm what "abeam to starboard" means in terms of true bearing from the ship, given your course of 115° T • Carefully compute the bearing rate in degrees per minute between 1850 and 1920 and check your arithmetic • Make sure to add the extra minutes needed to the correct starting time (1850 or 1920?) based on what your bearing-change calculation represents