Your vessel is on a course of 144°T at 20...

Question 1 of 2707066636ee928f7522a1c51a5ac

Your vessel is on a course of 144°T at 20 knots. At 0022 a light bears 117.5°T, and at 0035 the light bears 099°T. At what time and at what distance off will your vessel be when abeam of the light?

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Question 1 of 27070

🔍 Key Concepts

• Relative bearings vs true bearings and how "abeam" is defined • Using Speed = Distance / Time with minutes converted to hours for a 20‑knot vessel • Solving a bearing triangle with two known bearings from the same position line to find the distance at a later bearing

💭 Think About

• How do you convert the two observed true bearings into relative bearings from your vessel’s heading of 144°T? What will the true bearing be when the light is exactly abeam to port? • If you draw your track as a straight line and plot the light’s three bearings (first, second, and abeam), what geometric shape or triangle do you get? Which angles in that triangle are known from the bearing changes? • Once you know the distance run between the first and second bearing, and the included angle in the triangle, how can you use basic trigonometry or geometry to find the perpendicular distance from your track to the light when abeam?

✅ Before You Answer

• Confirm that "abeam" means 90° from your heading (port side in this case), and compute the corresponding true bearing of the light at that moment. • Be sure to convert the 13‑minute interval between 0022 and 0035 into hours before using the speed‑distance‑time formula at 20 knots. • After finding the distance run between the two observed bearings, check that your triangle sides and angles make sense (no angle > 180°, and the closest point occurs when the bearing change is symmetric about the abeam point).