🔍 Key Concepts

• Relative bearing vs. course and how to sketch the situation from the ship to the light • Using a right triangle / trigonometry to get the distance off at closest point of approach (CPA) • How changing course changes the relative bearing at CPA so that abeam distance = 3.5 miles

💭 Think About

• First, make a clear diagram: draw your present course, mark the light’s position based on its relative bearing (10° on the port bow) and range (8.3 miles). What does that triangle look like? • Ask yourself: if you keep the same course, will you pass inside or outside 3.5 miles? How can you see that from the diagram or by basic trigonometry? • Think about what new relative bearing at the moment of abeam passage (CPA) would give you a lateral separation of 3.5 miles from the light, starting from the known initial position.

✅ Before You Answer

• Be sure to convert relative bearing (10° on the port bow) to a true line from your ship to the light using your course of 283°pgc before you draw or calculate. • Check that the triangle you use has the correct initial range (8.3 miles) and that your chosen course gives a perpendicular distance of 3.5 miles from the track to the light. • Verify that the new course you select makes sense: does the light stay on the port side and will you pass it abeam (roughly 90° relative) at your intended closest distance?