You are underway on a course of 135° pgc at...

Question 1 of 2707066636eea28f7522a1c51b727

You are underway on a course of 135° pgc at 15 knots, and you sight a lighthouse dead ahead at a range of 12.5 miles at 1145. What course would you steer to leave the lighthouse 3.0 miles off your port beam?

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Question 1 of 27070

🔍 Key Concepts

• relative bearings and beam distance when passing an object abeam • the right triangle formed by your track, the closest point of approach (CPA), and the line from you to the lighthouse • using speed–time–distance to check how long it takes to reach the CPA point

💭 Think About

• Draw a simple sketch: your present position, the lighthouse ahead, and the point where it will be 3 miles on your port beam. What geometric shape does that make? • If the lighthouse will be 3 miles off your port beam, what will be the distance from you to the lighthouse at that beam position? Use Pythagorean theorem. • Once you know that distance, think about how the line of position from the lighthouse must shift relative to your original course. Does your new course need to be more to port or more to starboard than 135° pgc?

✅ Before You Answer

• Make sure you treat 3.0 miles off the port beam as the perpendicular distance from your track to the lighthouse at CPA. • Confirm that you are using nautical miles consistently in your right-triangle calculations. • Before choosing a course, double-check: does that course alteration logically put the lighthouse on your port side at the closest point, not starboard?